JP2008141154A - Composite heat dissipation plate, its manufacturing method, and thermal stress relaxation plate used for it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide means for effectively absorbing thermal stress based on a thermal expansion difference between ceramic and a heat dissipation plate and improving brazing property between a thermal stress relaxation plate, a heat dissipation plate, and ceramic in a composite heat dissipation plate for dissipating heat of a heater such as a power IC joined with the ceramic through the heat dissipation plate. <P>SOLUTION: A stress relaxation plate 4 is disposed between ceramic and a heat dissipation plate 2. The stress relaxation plate 4 includes many arc-shaped slits 5 concentrically from the center on its flat plane. On the same concentric circle, a bridge part 6 is disposed between opposite ends of the arc-shaped slit 5 as a non-slit part to easily integrally manufacture the stress relaxation plate 4 with press processing. an opening is formed between each arc-shaped slit 5 of the thermal stress relaxation plate 4 and a peripheral edge of the thermal stress relaxation plate 4 via a degassing slit 16. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a composite heat radiating plate for radiating heat generated from a semiconductor such as a power IC and a thermal stress relaxation plate used therefor. Furthermore, it is related with the improvement of the brazing property.

  Power ICs, power module packages, etc. are heat generating elements that generate a large amount of heat, and their back side is connected to a ceramic insulating layer, and the ceramic insulating layer is joined to a metal heat dissipating plate via the heat dissipating plate. The heat generated from a power IC or the like is dissipated. In such a composite heat sink, the temperature cycle may be repeated thousands of times with repeated ON-OFF operation of the power IC, and at that time, due to the difference between the thermal expansion coefficient of the ceramic and the thermal expansion coefficient of the heat sink, There is a risk of cracking in the ceramic. In the case where the ceramic and the heat radiating plate are brazed and fixed at a high temperature, the ceramic may be cracked due to the difference in thermal expansion coefficient in the cooling step after brazing.

Then, in order to prevent the crack, invention of the following patent document 1 and patent document 2 is proposed.
In the former, a ceramic insulating layer is bonded to a heat sink made of metal via an insert layer, and the first layer on the ceramic side of the heat sink and a second layer bonded to the first layer are provided. The coefficient of thermal expansion is greater than that of the second layer.
In the latter, a metal layer is laminated on the surface of a ceramic substrate via a brazing material such as Al-Si, and the relationship between the hardness and thickness of the metal layer and the thickness and bending strength of the ceramic substrate is a specific value. It is a thing.

JP 2004-241567 A JP 2001-144234 A

  The proposals described in the above patent documents may lack both mechanical strength and reliability.

Further, when brazing and fixing a composite heat sink made of aluminum by vacuum brazing, the internal brazing property tends to be lower than that of the outer peripheral portion. This is based on the fact that, in vacuum brazing of aluminum, aluminum plates are bonded well by securing good wettability while destroying the oxide film on the surface of the material by Mg added to the brazing material. When joining flat plates having a relatively large brazing surface, such as a composite heat dissipation plate, the evaporation of Mg inside is worse than the outer periphery, and there is a possibility that the internal brazing may not be performed sufficiently.
When such a brazing defect occurs, there is a possibility that heat generated from the electronic component cannot be quickly dissipated. Therefore, an object of the present invention is to solve the various problems.

The present invention described in claim 1 is a composite heat radiating plate in which a ceramic (1) and a metal heat radiating plate (2) are joined in the thickness direction, and a heating element (3) is attached to the ceramic (1).
Between the ceramic (1) and the heat sink (2), a metal thermal stress relaxation plate (4) is interposed by brazing,
In the plane of the thermal stress relaxation plate (4), a large number of arc-shaped slits (5) are formed radially concentrically from the central portion,
Each arcuate slit (5) is provided with a bridge (6) as a non-slit part between both ends, and each bridge (6) attached to each arcuate slit (5) adjacent in the radial direction is It is a composite heat sink characterized by being arrange | positioned in the mutually different position in the circumferential direction.

The present invention according to claim 2 is the method according to claim 1,
A plurality of arc-shaped slits (5) of the thermal stress relaxation plate (4) are present on the same circumference, and the same number of the bridge portions (6) are composite heat sinks between the slits (5). is there.
According to a third aspect of the present invention, in the first or second aspect,
An arcuate member (7) having a width smaller than the width of the slit (5) and having the same thickness as the plate (4) is provided in each arcuate slit (5) of the thermal stress relaxation plate (4). It is an internal composite heat sink.

The present invention as set forth in claim 4 is characterized in that, in claim 3,
The thermal stress relaxation plate (4) is provided with a connecting slit (9) that connects between each arc-shaped slit (5) adjacent in the radial direction,
A plurality of the arcuate members (7) are each formed in a plane C shape, and the arcuate members (7) are connected to each other in the radial direction by connecting portions (8) to form a heat transfer plate (10).
The width of each connection portion (8) of the heat transfer plate (10) is narrower than the width of the connection slit (9),
The heat transfer plate (10) is a composite heat radiating plate built in the thermal stress relaxation plate (4) so that the connection portion (8) is disposed in the connecting slit (9).

The present invention according to claim 5 is the invention according to claim 4,
A positioning projection (11) is provided on the inner peripheral surface of each arc-shaped slit (5) of the thermal stress relaxation plate (4),
The projection (11) is a composite heat radiating plate configured so as to come into contact with the peripheral surface of the arcuate material (7) of the heat transfer plate (10).
The invention according to claim 6 is any one of claims 1 to 5,
The ceramic (1) is a composite heat radiating plate in which a flat metal plate (15) is bonded to the entire surface of both sides or one side.

A seventh aspect of the present invention provides the method according to any one of the first to sixth aspects,
Each of the arc-shaped slits (5) of the thermal stress relaxation plate (4) is opened at the outer peripheral edge of the plane of the thermal stress relaxation plate (4) through a venting slit (16). It is a heat sink.
The present invention described in claim 8 provides the method according to claim 7,
The thermal radiation relaxation plate (4) is a composite heat radiating plate formed in a planar square shape, and the gas vent slit (16) is opened on one or more sides thereof.

The present invention according to claim 9 is the invention according to claim 8,
It is a composite heat radiating plate in which the gas vent slits (16) are opened around the four sides of the thermal stress relaxation plate (4).
A tenth aspect of the present invention provides the method according to any one of the seventh to ninth aspects,
The heat sink (2) and the thermal stress relaxation plate (4) are made of aluminum,
The brazing is a composite heat radiating plate formed by vacuum brazing using a brazing material made of an aluminum alloy containing Mg.

  The present invention according to claim 11 is a thermal stress relaxation plate used for the composite heat sink according to any one of claims 1 to 10.

The present invention described in claim 12 is a method of manufacturing a composite heat sink according to claim 4,
The plate is cut or punched to form the thermal stress relaxation plate (4) having the arc slits (5) and the connection slits (9), and the arc slits (5) and the connection slits (9) are formed. A method of manufacturing a composite heat radiating plate, characterized in that the falling pieces that fall off from the plate at the time of use are used as the heat transfer plate (10), and the heat transfer plate (10) is disposed in the thermal stress relaxation plate (4). It is.
The present invention according to claim 13 is the invention according to claim 12,
Each of the arc-shaped slits (5) of the thermal stress relaxation plate (4) is manufactured by a method of manufacturing a composite heat radiating plate opened to the outer peripheral edge of the plane of the thermal stress relaxation plate (4) through a venting slit (16). is there.

  The composite heat sink of the present invention has a stress relaxation plate 4 interposed by brazing between the ceramic 1 and the heat sink 2, and a number of arc-shaped slits 5 are formed concentrically on the stress relaxation plate 4. Therefore, thermal stress based on the difference in thermal expansion coefficient between the ceramic 1 and the heat radiating plate 2 can be effectively absorbed by the stress relaxation plate 4. At the same time, the heat transfer of the ceramic 1 can be efficiently transmitted to the heat radiating plate 2 and radiated by the metal stress relaxation plate 4. Moreover, since the bridge | bridging part 6 as a non-slit part is attached between the both ends of the arc-shaped slit 5 on the same periphery, the stress relaxation plate 4 can be integrally formed with a press molding body. Further, since the bridge portions 6 of the arc-shaped slits 5 adjacent to each other in the radial direction are different from each other in the circumferential direction, the elongation of the portion due to the presence of the bridge portions 6 can be reliably absorbed by the adjacent arc-shaped slits 5. . The stress relaxation plate is made of a metal material, and is brazed and fixed to a ceramic and metallic heat dissipation plate at a large number of portions between the arc-shaped slits 5, so that a composite heat dissipation plate with high mechanical strength is obtained.

In the above configuration, a plurality of arc-shaped slits 5 of the stress relaxation plate 4 can exist on the same circumference, and the same number of bridge portions 6 can exist between the arc-shaped slits 5. By doing so, thermal stress can be effectively absorbed.
In the above-described configuration, the arc-shaped material 7 having a width smaller than the width of the arc-shaped slit 5 and having the same thickness as the stress-relaxing plate 4 is provided in each arc-shaped slit 5 of the stress relaxation plate 4. it can. In this case, due to the presence of the arcuate material 7, the heat transfer area is widened, and the heat transfer properties of the ceramic 1 and the heat sink 2 can be further improved.

  In the above-described configuration, the stress relaxation plate 4 is provided with the connecting slit 9 for connecting the arc-shaped slits 5 adjacent in the radial direction, and a plurality of arc-shaped members 7 each formed in a plane C shape are connected by the connecting portion 8 in the radial direction. The heat transfer plate 10 can be connected to form the heat transfer plate 10 in the arc-shaped slit 5 of the stress relaxation plate 4. In this case, the stress relief plate 4 and the heat transfer plate 10 are each formed of a press-molded body, and by combining them, a composite heat radiating plate that is easy to manufacture, has good heat transfer, and can effectively absorb thermal stress is provided. it can.

In the above configuration, the positioning protrusion 11 is provided on the inner peripheral surface of the arc-shaped slit 5 of the stress relaxation plate 4, and the protrusion 11 can be configured to contact the peripheral surface of the arc-shaped member 7 of the heat transfer plate 10. . In this case, the assembly of the stress relaxation plate 4 and the heat transfer plate 10 can be facilitated and the mass productivity can be increased.
In the above configuration, a flat metal plate 15 can be bonded to both sides or one side of the ceramic over the entire surface. In this case, the strength of the composite heat sink is increased and the appearance is improved.

In the above configuration, when each arc-shaped slit 5 provided concentrically on the thermal stress relaxation plate 4 is opened at the edge of the thermal stress relaxation plate 4 through a gas venting slit 16, an arc shape is formed when brazing. The gas in the slit 5 is discharged to the outside, and brazing is reliably performed to the inside, whereby the heat transfer between the ceramic 1 and the heat radiating plate 2 can be kept good.
Further, due to the presence of the gas vent slit 16 opened at the edge of the thermal stress relaxation plate 4, the thermal stress relaxation plate 4 is easily deformed in the circumferential direction, and between the ceramic 1 and the thermal stress relaxation plate 4. The generated thermal stress can be effectively absorbed and the ceramic 1 can be prevented from cracking.

  In the above configuration, when the gas vent slits 16 are opened on the four circumferences of the thermal stress relaxation plate 4, the gas vents are more effectively vented at the time of brazing, and the gas vent slits 16 existing on the four circumferences are used in the circumferential direction. Can be absorbed more effectively.

  In any of the above-described configurations, when the heat sink 2 and the thermal stress relaxation plate 4 are made of aluminum and the brazing material is made of an aluminum alloy containing Mg and brazed by vacuum brazing, This facilitates evaporation of Mg, sufficiently destroys the oxide films on the surfaces of the heat radiating plate 2 and the thermal stress relaxation plate 4 to the inside of the plate, and allows good brazing to the inside. Thereby, the heat transfer property in the composite heat sink made of aluminum can be improved.

  Conversely, in vacuum brazing of aluminum, if there is no degassing slit 16 in the thermal stress relaxation plate 4, the evaporation of Mg in the interior will be less than the outer periphery of the thermal stress relaxation plate 4. An oxide film formed on the surface of the thermal stress relaxation plate 4 or the like cannot be sufficiently destroyed during the brazing, and a brazing failure occurs in that portion. However, according to the present invention, the presence of the gas vent slit 16 promotes the evaporation of Mg to the inside of the thermal stress relaxation plate 4, destroys the oxide film, and can maintain a good brazing property.

  In the above configuration, the stress relaxation plate 4 used for the composite heat sink can effectively absorb the thermal stress of the composite heat sink.

In the method of manufacturing the composite heat sink according to claim 12, the thermal stress relaxation plate 4 having the arc-shaped slits 5 and the connecting slits (9) is formed by cutting or punching the plate. In addition, the piece that has fallen off from the plate when the connecting slit (9) is formed is used as the heat transfer plate 10, and the heat transfer plate 10 is disposed in the thermal stress relaxation plate 4. According to this, there is no waste of material, and the composite heat sink can be manufactured quickly and easily.
In the above manufacturing method, when each arc-shaped slit 5 of the thermal stress relaxation plate 4 is opened to the outer peripheral edge of the plane of the thermal stress relaxation plate 4 through the gas vent slit 16, the gas vent slit 16. This facilitates the evaporation of Mg to the inside of the thermal stress relaxation plate 4, breaks the oxide film, and maintains good brazing properties.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view of a stress relaxation plate 4 used in the composite heat sink of the present invention and a cross-sectional view taken along the lines B-B and C-C thereof. FIG. 2 is a schematic sectional view of the composite heat sink.
As shown in FIG. 2, the composite heat radiating plate 14 has the heating element 3 joined to the surface of the ceramic 1 via a brazing material 13. As the heating element 3, for example, a power IC, a power module package, or other electric parts are attached.
The ceramic 1 is formed of Si ₃ N ₄ , Al ₂ O ₃ or the like. A heat radiating plate 2 is joined to the ceramic 1 through a stress relaxation plate 4 by a brazing material 13. That is, the brazing material 13 is disposed on both surfaces of the stress relaxation plate 4 and they are brazed together.
In addition, the heat sink 2 may be provided with fins for promoting heat dissipation. Then, cooling air is blown to the heat radiating plate 2 by a fan (not shown) to cool it.

In this example, the stress relaxation plate 4 has a large number of arc-shaped slits 5 shown in FIG. 1 spaced apart from each other in the radial direction and formed in the circumferential direction. In this example, the arcuate slits 5 are formed in an arcuate shape, and a plurality of arcuate slits 5 (four in this example) are arranged on the same circumference, and a bridge portion 6 is provided between the arcuate slits 5. It has been. The bridge portions 6 of the arcuate slits 5 adjacent in the radial direction are displaced so as not to overlap each other. Thereby, the stress relaxation plate 4 can be press-molded integrally, and the thermal stress in the plane direction based on the difference in thermal expansion between the ceramic 1 and the heat radiating plate 2 is effectively absorbed.
In this example, the stress relieving plate 4 has a rectangular outer periphery, and a large number of arc-shaped slits 5 are arranged outside the center thereof. Such a stress relieving plate 4 is formed by press-forming a metal plate to form the arc-shaped slit 5. It can be manufactured by punching out the part. As an example of the material of the stress relaxation plate 4, an aluminum plate, a stainless steel plate, a steel plate, or the like can be used.

Next, FIG. 3 is a plan view showing another example of the stress relaxation plate 4 and sectional views taken along the lines BB and CC.
The stress relaxation plate 4 of this example incorporates the heat transfer plate 10 of FIG. 4 and is used as a combination plate 12 as shown in FIG. Such a combination of the combination plates 12 increases the heat transfer area between the ceramic 1 and the heat radiating plate 2 by increasing the heat transfer area due to the presence of the heat transfer plate 10 while having a large number of slits.
The stress relaxation plate 4 includes arc-shaped slits 5 each formed in a C shape, and connecting slits 9 that connect between the C-shaped intermediate portions. A plurality of positioning projections 11 protrude from the inner peripheral surface of the arc-shaped slit 5. Further, arc-shaped slits 5 are provided at the four corners of the stress relaxation plate 4, and the arc-shaped slit 5 and the C-shaped arc-shaped slit 5 are also communicated with each other by a connecting slit 9.

  Next, in the heat transfer plate 10 shown in FIG. 4, arc-shaped members 7 each formed in a C shape are arranged on a concentric circle, and the arc-shaped members 7 are connected by the connecting portions 8. Furthermore, four short arc-shaped members 7 are provided at positions matching the arc-shaped slits 5 arranged at the four corners of the stress relaxation plate 4. The short arc-shaped material 7 and the C-shaped arc-shaped material 7 are connected by a connecting portion 8. The width of each arc-shaped member 7 is smaller than the width of the arc-shaped slit 5 of the stress relaxation plate 4 and equal to the width between the opposing protrusions 11. Further, the width of the connecting portion 8 is formed to be narrower than the width of the connecting slit 9 of the stress relaxation plate 4. Further, the thickness of the heat transfer plate 10 is formed to be equal to the thickness of the stress relaxation plate 4, and each is formed of a metal plate. Preferably, an aluminum clad material in which a brazing material is coated on both surfaces of the stress relaxation plate 4 and the heat transfer plate 10 is used.

Then, as shown in FIG. 5, the two are combined, and in FIG. 2, the brazing material 13 is integrally brazed and fixed between the ceramic 1 and the heat radiating plate 2. The stress relaxation plate 4 and the heat transfer plate 10 are each formed of a press-formed body.
By constructing the composite heat sink 14 with such a combination plate 12 composed of the heat transfer plate 10 and the stress relaxation plate 4, the heat transfer between the ceramic 1 and the heat sink 2 can be improved and a large number of them can be arranged in the radial direction. Thinner arc-shaped grooves can be formed on the concentric circles to effectively absorb thermal stress based on the difference in thermal expansion.

Next, FIG. 6 shows an absorption state of thermal stress when the combination plate 12 has a ceramic and a heat radiating plate (not shown) on the front side and the back side, respectively, and the heating element 3 is arranged on the front side of the ceramic 1. FIG.
The heat generated by the heating element 3 is transferred to the heat radiating plate 2 through the ceramic 1 in FIG. 2, the stress relaxation plate 4 and the heat transfer plate 10 in FIG. The thermal stress based on the difference in thermal expansion between the ceramic 1 and the heat sink 2 at this time is absorbed by the change in the interval between the arcuate thin grooves.

  Next, FIG. 7 shows still another embodiment of the present invention. In this example, the composite heat sink has a flat metal plate 15 bonded to both surfaces of the ceramic. The metal plate 15 does not have a slit like the thermal stress relaxation plate 4. As an example of the metal plate 15, an aluminum plate having a rust-preventive plating film on its surface can be used. The composite heat radiating plate having such a structure has high strength and good appearance. The metal plate 15 may be attached only to one side of the ceramic.

FIG. 8 shows another thermal stress relaxation plate 4 used for the composite heat sink of the present invention, (A) is a plan view thereof, (B) is a cross-sectional view taken along the line BB of (A), and (C) is ( It is CC sectional view taken on the line of A). FIG. 9 is a cross-sectional view of the composite heat radiating plate 14 using the thermal stress relaxation plate 4, and is a cross-sectional view taken along the line BB of FIG.
As shown in FIG. 9, the composite heat sink 14 is brazed and joined with an insulating ceramic 1 and a metal heat sink 2 via a thermal stress relaxation plate 4 in the thickness direction. It can be attached.

  As shown in FIG. 8, the thermal stress relaxation plate 4 has a large number of arc-shaped slits 5 formed concentrically from the central portion on the plane thereof so as to be spaced apart from each other in the circumferential direction and the radial direction. In this example, each pair of the inner arcuate slit 5 and the outer arcuate slit 5 is arranged 90 ° apart from each other in the circumferential direction. The inner arc-shaped slit 5 and the outer arc-shaped slit 5 communicate with each side of the rectangular thermal stress relaxation plate 4 via a venting slit 16, and the venting slit 16 is formed on the outer periphery of the thermal stress relaxation plate 4. It is open. In this example, the thermal stress relaxation plate 4 and the heat radiating plate 2 are made of an aluminum material or an alloy material thereof, and the surface thereof is clad with a brazing material.

  Then, the thermal stress relaxation plate 4 and the ceramic 1 are sequentially laminated on the aluminum radiator plate 2, and the three members are integrally brazed and fixed in a vacuum furnace. At this time, the air present in the arc-shaped slit 5 is completely discharged to the outside through the respective gas vent slits 16. Thus, since each inner arc-shaped slit 5 is also opened to the outer periphery through the gas venting slit 16, Mg in the brazing material evaporates to the center of the thermal stress relaxation plate 4, and an oxide film on the surface of the material Can be destroyed, the wettability of the brazing material can be improved, and reliable brazing can be performed.

  Next, FIG. 10 shows another example of the thermal stress relaxation plate 4. In the thermal stress relaxation plate 4 of this example, the inner pair of arc-shaped slits 5 and the outer arc-shaped slits 5 form the communication portions 9. The pair of arc-shaped slits 5 on the outside and the outer periphery of the thermal stress relaxation plate 4 are opened to the outer periphery by a pair of venting slits 16.

Further, in the example of FIG. 11, only one arcuate slit 5 on the center side is opened to the outer periphery of the thermal stress relaxation plate 4 through the gas venting slit 16, and the communicating portions 9 are respectively connected to the arcuate slits 5 on the inner side. The arc-shaped slits 5 are communicated with each other.
In addition, by making each arc-shaped slit 5 communicate with the gas vent slit 16, the air in the arc-shaped slit 5 is completely discharged in the vacuum furnace, improving the vacuum degree of the vacuum furnace, and the reliability of vacuum brazing. Can be further improved.

  Next, FIG. 12 is a plan view of another thermal stress relaxation plate 4 and heat transfer plate 10 used in the method for manufacturing a composite heat sink of the present invention, and FIG. 13 is a plan view showing the combined state. In the present invention, the thermal stress relaxation plate 4 having the arc-shaped slits 5 and the connecting slits 9 is formed by cutting the plate with a laser or the like or punching with a press machine. Then, the falling pieces that have fallen out of the plate when the arc-shaped slits 5 and the connecting slits 9 of the thermal stress relaxation plate 4 are formed are used as the heat transfer plate 10, and the heat transfer plate 10 is placed in the thermal stress relaxation plate 4. The composite heat radiating plate is manufactured by arranging them.

  Thereby, manufacture becomes easy and waste of material can be eliminated. In the laser cutting process, the portion irradiated with the laser is melted down, so that the width of the heat transfer plate 10 dropped from the plate is narrower than the widths of the arc-shaped slits 5 and the connecting slits 9 of the thermal stress relaxation plate 4. Therefore, when the heat transfer plate 10 is disposed in the thermal stress relaxation plate 4, a slight gap is generated between the two. In the case of press molding, the mold can be formed in advance so that a gap is formed. Each of the arc-shaped slits 5 of the thermal stress relaxation plate 4 is opened at the outer peripheral edge of the plane of the thermal stress relaxation plate 4 through a venting slit 16. Corresponding to the degassing slit 16, a convex portion 17 is formed on the heat transfer plate 10.

The top view of the stress relaxation plate 4 which comprises a part of composite heat sink of this invention, its BB, and CC sectional view taken on the line. The cross-sectional schematic of the composite heat sink. The top view of the stress relaxation plate 4 which comprises a part of 2nd composite heat sink of this invention, its BB, and CC sectional drawing. The top view of the heat-transfer plate 10 which comprises the composite heat sink.

The top view of the combination plate 12 which has arrange | positioned the heat-transfer plate 10 in each arc-shaped slit 5 of FIG. Explanatory drawing which shows the state of absorption of a thermal stress when the heat generating body 3 is arrange | positioned through the ceramic which is not illustrated in the combination plate 12. FIG. The cross-sectional schematic of the other composite heat sink of this invention. The thermal stress relaxation plate 4 used for the other composite heat sink of this invention is shown, (A) is a top view, (B) is BB arrow sectional drawing of (A), (C) is C of (A). -C arrow sectional drawing.

It is a cross-sectional view of the composite heat sink of the present invention, and is a cross-sectional view taken along line BB in FIG. The top view of the other thermal stress relaxation plate 4 used for the composite heat sink of this invention. The top view of the further another thermal stress relaxation plate 4 used for the composite heat sink of this invention. The top view of the other thermal stress relaxation plate 4 and the heat-transfer plate 10 used for the composite heat sink of this invention. The top view of the composite heat sink.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic 2 Heat sink 3 Heat generating body 4 Stress relaxation plate 5 Arc-shaped slit 6 Bridge part 7 Arc-shaped material

8 Connection 9 Link slit
10 Heat transfer plate
11 Protrusion
12 Combination plate
13 Brazing material
14 Composite heat sink
15 Metal plate
16 Gas vent slit
17 Convex

Claims (13)

In a composite heat sink where a ceramic (1) and a metal heat sink (2) are joined in the thickness direction, and a heating element (3) is attached to the ceramic (1),
Between the ceramic (1) and the heat sink (2), a metal thermal stress relaxation plate (4) is interposed by brazing,
In the plane of the thermal stress relaxation plate (4), a large number of arc-shaped slits (5) are formed radially concentrically from the central portion,
Each arcuate slit (5) is provided with a bridge (6) as a non-slit part between both ends thereof, and each bridge (6) attached to each arcuate slit (5) adjacent in the radial direction is A composite heat radiating plate, wherein the composite heat radiating plate is disposed at different positions in the circumferential direction. In claim 1,
A composite heat radiating plate in which a plurality of arc-shaped slits (5) of the thermal stress relaxation plate (4) are present on the same circumference, and the same number of the bridge portions (6) are present between the slits (5). In claim 1 or claim 2,
An arcuate member (7) having a width smaller than the width of the slit (5) and having the same thickness as the plate (4) is provided in each arcuate slit (5) of the thermal stress relaxation plate (4). Built-in composite heat sink. In claim 3,
The thermal stress relaxation plate (4) is provided with a connecting slit (9) that connects between each arc-shaped slit (5) adjacent in the radial direction,
A plurality of the arcuate members (7) are each formed in a plane C shape, and the arcuate members (7) are connected to each other in the radial direction by connecting portions (8) to form a heat transfer plate (10).
The width of each connection portion (8) of the heat transfer plate (10) is narrower than the width of the connection slit (9),
A composite heat radiating plate in which the heat transfer plate (10) is housed in a thermal stress relaxation plate (4) so that the connecting portion (8) is disposed in the connecting slit (9). In claim 4,
A positioning projection (11) is provided on the inner peripheral surface of each arc-shaped slit (5) of the thermal stress relaxation plate (4),
A composite heat radiating plate configured such that the protrusion (11) is in contact with the peripheral surface of the arcuate member (7) of the heat transfer plate (10). In any one of Claims 1-5,
The ceramic (1) is a composite heat radiating plate in which a flat metal plate (15) is bonded to the entire surface of both sides or one side. In any one of Claims 1-6,
Each of the arc-shaped slits (5) of the thermal stress relaxation plate (4) is opened at the outer peripheral edge of the plane of the thermal stress relaxation plate (4) through a venting slit (16). Heat sink. In claim 7,
A composite heat radiating plate in which the thermal stress relaxation plate (4) is formed in a flat rectangular shape, and the gas vent slit (16) is opened on one or more sides thereof. In claim 8,
A composite heat radiating plate in which the degassing slits (16) are opened around the circumference of the thermal stress relaxation plate (4). In any one of Claims 7-9,
The heat sink (2) and the thermal stress relaxation plate (4) are made of aluminum,
A composite heat radiating plate in which the brazing is performed by vacuum brazing using a brazing material made of an aluminum alloy containing Mg.   The thermal-stress relaxation plate used for the composite heat sink in any one of Claims 1-10. In the manufacturing method of the composite heat sink of Claim 4,
The plate is cut or punched to form the thermal stress relaxation plate (4) having the arc slits (5) and the connection slits (9), and the arc slits (5) and the connection slits (9) are formed. A method of manufacturing a composite heat radiating plate, characterized in that the falling pieces that fall off from the plate at the time of use are used as the heat transfer plate (10), and the heat transfer plate (10) is disposed in the thermal stress relaxation plate (4). . In claim 12,
A method of manufacturing a composite heat radiating plate in which each arc-shaped slit (5) of the thermal stress relaxation plate (4) is opened at the outer peripheral edge of the plane of the thermal stress relaxation plate (4) through a gas venting slit (16).

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