JP2002026199A - Forming method of heat dissipating member for electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the forming method of a heat dissipation member for an electronic component, which can properly process the planarity of a metal, plate if the plate thickness of the metal plate is of comparatively thick. SOLUTION: This method is a method for forming a heat dissipation member 1, which is bonded to a package body 100, is protuberantly formed with a projected stand part 2 for providing an electronic component S on the side of the surface on one side of its surfaces and consists of a metal having thermal conductivity, and the member 1 is formed by the method, where a recessed place 3 of a dimension shallower than the plate thickness of a metal plate 10 is formed pressingly by a press or the like from the side of the surface on one side of the surfaces of the plate 10 and at the same time, the metal of the recessed plate 3 is made to transfer to the side of the other surface of the plate 10 to protuberantly form the projected stand part 2, and thereafter, the side of the surface on one side of the plate 10 is cut until the side of the surface on one side reaches the bottom of the plate 3 to form the surface of the plate 10 into a flat surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipating member for dissipating heat by bringing an electronic component such as an integrated circuit, which generates heat, into contact with a metal plate. To a heat dissipating member for electronic components.

[0002]

2. Description of the Related Art As shown in FIG. 8, a package for an electronic component called a heat slug type is mainly composed of a ceramic package body 100 and a heat radiation member 101. The ceramic package body 100 is formed in a substantially square frame shape obtained by laminating a plurality of predetermined green sheets (not shown), thermocompression bonding, and firing. Further, on the upper surface, a metallization layer 10 on which a bonding pad for bonding to the electrode of the electronic component S with the wire W is formed.
2 are formed. In the center of the package body 100, a through hole 10 penetrating through the upper and lower surfaces in a substantially square shape is provided.
3 are formed.

On the other hand, the heat radiating member 101 is made of a metal plate made of, for example, oxygen-free copper. A slightly small, substantially square protruding base 101a is formed so as to protrude in a convex shape in cross section.

The through hole 1 of the package body 100
03, the projecting part 101a of the heat radiation member 101 is positioned at the center from the lower surface side and inserted.
01b is fixed to the lower surface of the package body 100 by, for example, silver brazing (foil). Note that a metallized layer for brazing and fixing the heat radiating member 101 is formed on the lower surface side of the package body 100.

[0005] Further, the protrusion 101a of the heat radiation member 101
The electronic component S is mounted on the upper surface of the metallization layer 102, and the electrodes of the electronic component S and the bonding pads of the metallization layer 102 are electrically connected by bonding with a wire W. Thus, the protruding part 101a of the heat radiation member 101
And the through hole 103 of the package body 100, a cavity is formed, and the electronic component S is housed inside the cavity.

With this configuration, when the electronic component S generates heat, it is transmitted to the protruding portion 101a of the heat radiating member 101 and radiated. However, since the heat radiation by the heat radiation member 101 is usually insufficient, the heat radiator 105 is used as an auxiliary. As is generally known, the radiator 105 has a large number of radiating fins 105a integrally formed on one side and a flat surface on the other side. Then, by joining the other surface of the radiator 105 to the radiating member 101, heat generated from the electronic component S transmitted to the radiating member 101 is transmitted to the radiator 105, and a large radiating area by the radiating fin 105a is provided. Dissipates heat to the outside.

[0007]

In the above-mentioned conventional heat radiating member 101, generally, a protruding portion 101a is formed by pressing a metal plate having a predetermined thickness into a sheet metal. For this reason, the cavity 10 is provided on the lower surface side of the abutment 101a.
6 are formed. However, when the radiator 105 is surface-bonded to the heat radiating member 101 in order to supplement the heat radiation of the heat radiating member 101, the bonding area is reduced by the cavity 106. As is well known, air has the lowest thermal conductivity,
Due to the existence of such a cavity 106, the heat radiation member 101
There is a problem that the transmission efficiency from the heat sink to the radiator 105 is significantly reduced.

Further, in order to improve the heat radiation of the electronic component S, it is necessary to join the electronic component S to the protruding portion 101a with a large joining area. Furthermore, in order to increase the heat radiation efficiency of the heat radiation member 101, it is necessary to increase the mass of the heat radiation member 101 itself. For this reason, it is necessary to increase the plate thickness of the heat radiation member 101 itself.

However, when the protruding portion 101a is formed from a thick metal plate by sheet metal working, the protruding portion 101a is formed.
Is curved and the flatness deteriorates. As a result, there is a problem that the bonding area with the electronic component S decreases and the transmission efficiency decreases. Accordingly, in order to obtain a certain degree of flatness on the upper surface of the protruding portion 101a, the thickness of the metal plate must be reduced, and there is a problem that the heat radiation efficiency of the heat radiation member 101 is limited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional method, and is intended to provide a heat radiating member for electronic parts which can be processed with good flatness even with a relatively large thickness. It is an object to provide a forming method.

[0011]

In order to achieve the above object, according to the first aspect of the present invention, a projecting base for projecting an electronic component on one surface side is formed so as to be joined to a package body. A method of forming a heat dissipating member made of metal having thermal conductivity, wherein the heat dissipating member is formed by pressing a recess having a dimension smaller than the thickness of the metal plate by pressing or the like from one side of the metal plate. After shifting the metal of the recess to the other surface side and projecting the protrusion, the one side of the metal plate is cut to the bottom surface of the recess to form a flat surface. And features.

According to a second aspect of the present invention, the recess formed on one side of the metal plate is formed in a substantially similar shape to the base having a predetermined shape slightly larger than the protruding base formed on the other side. It is characterized by doing.

According to a third aspect of the present invention, a recess is formed by pressing one side of the metal plate to transfer the metal of the recess to the other side, so that the metal plate has a protrusion on the other surface. The pressing step of projecting and forming the portion and the cutting step of cutting one surface side of the metal plate to the bottom surface of the recess to form a flat surface are repeated a plurality of times, and the one surface side of the metal plate is small. It is characterized in that, while being cut by a cutting allowance, a protruding portion formed to project from the other surface of the metal plate is gradually raised to a predetermined height.

Further, according to the present invention, the recess is formed by pressing one side of the metal plate and the metal of the recess is shifted to the other side of the metal plate to thereby provide a predetermined surface on the other side of the metal plate. A protruding protruding portion having a height is formed, and one surface side of the metal plate is cut a plurality of times to reach the bottom surface of the recess, thereby forming a flat surface.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for forming a heat radiating member for an electronic component according to the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 and FIG. 2 show a heat slug type package to which a heat radiating member for an electronic component according to the present invention is applied. The basic configuration of this package is the same as that of the electronic component package shown in FIG. 8, and the same reference numerals as those in FIG. 8 denote components, and a detailed description thereof will be omitted.

The electronic component package shown in FIG. 1 mainly includes a package body 100 made of ceramic and a heat radiating member 1. On the upper surface of the package body 100, a metallization layer 1 on which a bonding pad BP for bonding with an electrode TP formed on an electronic component S made of, for example, a semiconductor integrated circuit or the like by a wire W is formed.
02 is formed. A substantially square through hole 103 is formed in the center of the package body 100.

The heat dissipating member 1 is made of a metal plate made of, for example, oxygen-free copper, and a central portion of the heat dissipating member 1 formed in a flat plate shape has a through hole 1 of the package body 100.
A substantially square protruding base portion 2 smaller than the planar shape of No. 03 is formed so as to protrude in a convex cross section. And the package body 1
The projecting portion 2 of the heat radiating member 1 is positioned and inserted into the through hole 103 of the central portion 00 from the lower surface side, and the flat plate portion 4 of the heat radiating member 1 is fixed to the lower surface side of the package body 100.

Further, an electronic component S is mounted on the upper surface of the protruding portion 2 of the heat radiating member 1, and a wire W is provided between the electrode of the electronic component S and the bonding pad BP formed on the upper surface of the package body 100. Bonding and electrical connection. With the above configuration, a cavity is formed by the upper surface of the protruding portion 2 of the heat radiation member 1 and the through hole 103 of the package body 100, and the electronic component S is formed inside the cavity.
Is stored. Further, a heat radiator 105 is auxiliaryly joined to the lower surface side of the heat radiating member 1 as necessary, and the heat of the electronic component S transmitted to the heat radiating member 1 is transmitted to the heat radiator 105 to radiate heat to the outside. are doing.

Next, a method for forming the heat dissipating member 1 for electronic components will be described with reference to FIG. FIG. 3A shows a metal plate 10 serving as a material of the heat radiation member 1 and is selected from metal materials such as oxygen-free copper, copper alloy, stainless steel, and aluminum. FIG.
(B) shows the protruding step. After the metal plate 10 is placed in a state of being positioned with respect to the die 11 having a substantially square hole 11a installed in a press (not shown), the metal plate 10 is mounted on the press from one surface 10a side of the metal plate 10. The punch 12 is pressed. As a result, the recess 3 is formed on the one surface 10a side of the metal plate 10 and the metal plate 1
On the other surface 10b side of the die 11, the metal of the recess 3
By shifting into 1a, a substantially square protruding base 2 having a desired height h as the heat radiating member 1 is formed to protrude.

The external dimension w1 of the protruding portion 2 is a similar shape that is slightly smaller than the dimension w2 of the recess 3 on the opening side. Such a dimensional relationship is for always maintaining the connected state without cutting the protruding part 2 from the metal plate 10.

FIGS. 3C and 3D show a cutting process.
The cutter 13 is brought into contact with an end surface of the metal plate 10 by the cutter 13 so that the one surface 10a side of the metal plate 10 in which the recess 3 is formed by the above-described projecting process is substantially flush with the bottom surface of the recess 3. , One surface 10a of the metal plate 10
Move parallel to the side and cut. The cutter 13 used in this cutting step has, for example, a substantially arrow-shaped tooth portion 13a protruding from the center of the tip, and advances the cutter 13 in the direction of the arrow shown in the drawing, as shown in FIG. By moving to the position, the entire surface of the metal plate 10 on the one surface 10a side is cut.

Through the cutting step, the thickness of the flat plate portion 4 of the heat radiating member 1 is reduced, and the heat radiating member 1 is formed to have a predetermined thickness. As described above, in order to obtain the required thickness as the flat plate portion 4 of the heat radiating member 1, the metal plate 1 as a material is used.
The plate thickness of 0 may be a thickness obtained by adding the plate thickness of the flat plate portion 4 to the height of the protruding portion 2.

In this cutting step, in order to prevent the metal plate 10 from being displaced in the direction of the protruding portion 2 by the pressing force of the cutter 13, the pressing tool 14 is brought into contact with the other surface 10 b of the metal plate 10. It is desirable to keep. Thus, by performing the cutting process, the heat radiation member 1 shown in FIG. 3E is completed.

According to the above forming method, the metal plate 10
Is formed on the other surface 10b side of the
Is formed by cutting one surface 1 of the metal plate 10 having the recess 3 formed over the entire surface, so that the one surface 10a of the metal plate 10 has a uniform flatness over the entire surface. Further, by making the outer dimensions of the abutment 2 a similar shape slightly smaller than the opening side dimension of the recess 3, the punch 12 presses the periphery of the abutment 2 when the abutment 2 is formed to project. be able to. As a result, since the meat moves to the edge of the abutment 2, the upper surface of the abutment 2 can be formed with good flatness and high quality.

[Other Embodiments] FIG.
The protruding step shown in FIG.
The cutting step shown in (D) is repeated a plurality of times to cut the one side 10a of the metal plate 10 with a small cutting margin, and to fix the protruding part 2 projecting from the other surface 10b of the metal plate 10 to a predetermined position. The formation method of gradually increasing the height to the height is shown.

FIG. 4B-1 shows the first projecting step. This first protruding step is the same as the protruding step shown in FIG. 3B, except that the first recess 3 having a shallow depth is formed on one side 10 a of the metal plate 10. , Metal plate 1
0, the protruding portion 5 having a low height is formed on the other surface 10b side. That is, the punch 12 shown in FIG. 3B is pressed against the one side 10a of the metal plate 10 and the first depth 10a having a small depth is pressed.
Of the first recess 3 is transferred to the other surface 10b side of the metal plate 10 to reduce the height h.
A projection 5 is formed.

Thereafter, the process proceeds to the first cutting step shown in FIG. This first cutting step is the same as the cutting step shown in FIG.
Is flattened by cutting until one surface 10a is substantially flush with the bottom surface of the first recess 4.

FIG. 4B-2 shows the second projecting step.
By pressing the punch 12 from the one surface 10a side of the metal plate 10 formed flat by the first cutting step, and forming the second recess 6 having a further shallow depth, the second recess 6 is formed. 6 is transferred to the other surface 10b side of the metal plate 10,
A substantially square protruding base 2 having a desired height h is formed as the heat dissipating member 1 so as to protrude.

Thereafter, the process shifts to the second cutting step shown in FIG. 4C-2, and the one surface 10a side of the metal plate 10 is made substantially flush with the bottom surface of the second recess 6 by the cutter 13. Until it is flat. By repeating the first and second protruding steps and the cutting step in this way, the heat dissipating member 1 shown in FIG. 3E is completed.

Also in the first cutting step, the cutter 1
3 to prevent the metal plate 10 from being displaced in the direction of the protruding portion 5 by the pressing force of
It is desirable that the presser 15 shown in FIG. 3C also be in contact with the other side 10b of the metal plate 10 in the second cutting step.

In the second cutting step, the cutter 1
In the step 3, the cutting may be performed in a direction opposite to the first cutting step described above. That is, the cutter 131 is cut from the left side to the right side as shown by the two-dot line in FIG. As described above, by performing cutting in the opposite direction, the stress concentration applied to one side in the first cutting step can be returned to the opposite side, thereby preventing the occurrence of processing distortion due to the cutting.

According to the above other forming method, the first projecting step is followed by the first cutting step, and then the second projecting step is carried out by the second cutting step.
The cutting step and the step are repeated to gradually increase the height of the protruding portion 2 and to cut the one surface 1 of the metal plate 10 into thin portions, so that the punch for forming the protruding portion 2 protrudes. Since the pressing force of No. 12 is reduced and the cutting allowance is small, the stress on the metal plate 10 is reduced, and the processing distortion in each step can be suppressed. In particular, when forming the heat radiating member 1 having a large thickness, such a forming method is effective. The number of repetitions of the projecting step and the cutting step is appropriately set according to the thickness of the heat radiation member 1 or an appropriate cutting allowance according to the material.

FIG. 5 shows another embodiment in which one side 10a of the metal plate 10 is cut in a plurality of times in the cutting step shown in FIGS. 3 (C) and 3 (D). I have. In FIG. 5A, after the protruding step shown in FIG. 3B, the one surface 10a side of the metal plate 10 is divided into a plurality of times by the cutter 13 to be substantially flush with the bottom surface of the recess 3. An example is shown in which cutting is performed up to. That is, FIG.
In the example shown in (A), the one surface 10a side of the metal plate 10 is divided into two parts by the cutter 13 as shown by two two-dotted lines, and cut so that each cutting margin is reduced. I have. As a result, one cutting allowance can be reduced,
There is a feature that stress and stress on the metal plate 10 can be reduced and processing distortion can be suppressed.

FIG. 5B shows an example in which after being cut by a cutter, finishing is performed by sandpaper or the like. That is, after the protruding step shown in FIG. 3B, one side 10a of the metal plate 10 is
3 cuts to the vicinity of the bottom surface of the recess 3. Then, it is thinly cut as a finishing process by the endless sandpaper 16. As a result, the one surface 10a side of the metal plate 10 can be formed to have a better surface roughness than the cutting marks formed by the cutter 13.

FIG. 6 shows cutting means other than the cutter.
FIG. 6A shows an example in which the rotating blade 17 of the milling machine is moved to cut the one surface 10a side of the metal plate 10 so as to be substantially flush with the bottom surface of the recess 3. FIG.
(B) shows an example in which the one surface 10a side of the metal plate 10 is cut so as to be substantially flush with the bottom surface of the recess 3 by moving the glider 18 to the left in the drawing. Of course, other than the above example, the one surface 10a side of the metal plate 10 may be cut by an arbitrary cutting method. 5 and 6, the cutter 13, the endless sandpaper 16, and the rotary blade 1 of the milling machine are used.
7 and the metal plate 10 by the pressing force of the glider 18.
In order to prevent the metal plate 10 from being displaced in the direction of the protruding portion 2, it is desirable that the pressing tool 14 abut on the other surface 10 b of the metal plate 10.

FIG. 7 shows a unit U having four to five intermediate products as one unit. The unit U includes a metal plate as a raw material, for example, a hoop-shaped metal plate material 30 made of oxygen-free copper, a copper alloy, stainless steel, or aluminum.
From the heat dissipating member 1 by a progressive processing machine (not shown).
Is formed.

In the unit U, a slot 32 is formed around the adjacent heat radiating member intermediate products 31 and between them, and the unit U is connected to the hoop-shaped metal plate 30 via a connecting piece 33. This slot 32 is desirably formed at a drilling process stage in which a pilot hole 34 is drilled in the hoop-shaped metal plate 30 in the progressive processing machine described above. As described above, when the individual intermediate products 31 are connected to the hoop-shaped metal plate 30 via the connecting pieces 33, the warp and the flatness can be obtained independently without being affected by the metal plate 30 or the adjacent intermediate product. The connecting piece 33
In the final step, as shown in FIGS. 1 and 2, the package body 100 is fixed, and after the electronic component S is mounted on the upper surface of the protruding portion 2 of the heat radiating member 1, bonding is performed to perform electrical connection. Disconnected after connecting to

Further, the heat radiation member intermediate product 31 shown in FIG.
FIG. 3B shows a state after the protruding step described with reference to FIG. That is, the protruding portion 2 is formed on the other surface side of the intermediate heat radiating member 31, and the recess 3 is formed on one surface side. Furthermore, a connecting piece 3 for connecting the individual intermediate products 31
The bottom surface of the recess 3 and the bottom surface of the recess 3 are substantially flush with each other.

Thereafter, in a cutting step, one side of each of the heat radiating member intermediate products 31 formed in the unit U is sequentially adjusted to a thickness d so as to be substantially flush with the bottom surface of the recess 3 by a cutter (not shown). To cut. As a result, a plurality of heat radiation members 1 are formed in the unit U. After connecting the package body 100 and the electronic component S to the heat radiating members 1 in the mounting process, the connecting pieces 33 are cut. Since the connecting piece 33 is formed to be thin enough, the impact can be minimized even if it is cut after mounting.
And other adverse effects can be prevented.

In the embodiment described above, the lower surface of the heat dissipating member is formed as a flat surface by cutting one surface side of the metal plate to the vicinity of the bottom surface of the recess. For positioning with a component such as a radiator to be attached to the lower surface, or for attaching to an electronic device, a positioning projection or the like may be partially formed to protrude. Also, as an example of the use of the heat dissipating member, it has been described that the electronic component is mounted on the projecting portion. It may be joined to a container or the like, and various changes can be made without departing from the present invention.

[0041]

As described above, according to the method for forming a heat radiating member for an electronic component according to the present invention, after forming a projection on the other surface of the metal plate in advance, it is necessary to form the projection. Since one surface of the metal plate having the recess is cut, one surface of the metal plate can be formed with a uniform flatness. Also,
By making the external dimensions of the abutment part a similar shape slightly smaller than the opening side dimension of the recess, the abutment part is pressed to the periphery, so that the meat moves to the edge of the abutment part, Can be formed with good flatness. Furthermore, even a heat radiating member having a large thickness can be easily formed, and the heat radiating efficiency required as a heat radiating member can be increased.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a package using a heat dissipation member according to the present invention.

FIG. 2 is a cross-sectional view showing a state in which electronic components are mounted on a package using the heat dissipation member according to the present invention.

FIGS. 3A to 3E are process explanatory views showing a method for forming a heat dissipation member according to the present invention.

FIG. 4 (B-1) (B-2) (C-1) (C-2)
FIG. 4 is an explanatory view showing another method of forming a heat dissipation member according to the present invention.

FIGS. 5A and 5B are explanatory views showing a modification of the cutting step in the method for forming a heat radiating member according to the present invention.

FIGS. 6A and 6B are explanatory views showing another cutting step in the method for forming a heat radiating member according to the present invention.

FIG. 7 is a perspective view showing a unit of a heat radiating member according to the present invention.

FIG. 8 is a cross-sectional view showing a package using a conventional heat dissipation member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat radiating member 2 Projection part 3 Concave part 4 Flat plate part 10 Metal plate 10a One surface 10b The other surface 12 Punch 13 Cutter 100 Package body S Electronic components

Claims (4)

[Claims] 1. A method for forming a heat-dissipating member made of a metal having thermal conductivity, which is joined to a package body and protrudes a projecting portion for disposing an electronic component on one surface side. The member presses and forms a recess having a dimension smaller than the thickness of the metal plate from one side of the metal plate by pressing or the like, and shifts the metal of the recess to the other side to form the protrusion. And forming a flat surface by cutting one side of the metal plate to the bottom surface of the recess. 2. The electronic component according to claim 1, wherein the recess formed on one side of the metal plate has a substantially similar shape to that of the base having a predetermined shape formed on the other side. For forming a heat dissipating member for use. A pressing step of pressing and forming a recess from one surface side of the metal plate and shifting the metal of the recess to the other surface side to form a projecting portion on the other surface of the metal plate; The cutting step of cutting one side of the metal plate to the bottom surface of the recess and forming a flat surface is repeated a plurality of times, and cutting one side of the metal plate with a small cutting allowance,
The method for forming a heat radiating member for an electronic component according to claim 1, wherein a protruding portion formed on the other surface of the metal plate is gradually raised to a predetermined height. 4. A recess having a predetermined height is formed on the other surface of the metal plate by pressing a recess from one surface of the metal plate and transferring the metal of the recess to the other surface. 2. The method for forming a heat radiating member for an electronic component according to claim 1, wherein the one side of the metal plate is cut a plurality of times and cut to reach the bottom surface of the recess to form a flat surface.