JP6105437B2 - Heat dissipation device - Google Patents

Description

  The present invention relates to a heat dissipation device in which a circuit board on which an electronic element is mounted and a heat sink are integrated.

  In the present specification and claims, the term “aluminum” is used to include both aluminum and its alloys.

  As a method for dissipating the heat generated by an electronic element, a heat radiating device is known in which a circuit board on which the electronic element is mounted is brazed to a heat sink and these are integrated (see Patent Document 1).

  In the heat dissipation device described in Patent Document 1, a circuit layer is laminated on one surface of an insulating layer made of ceramic, a metal heat sink is laminated on the other surface via an aluminum layer, and each layer is brazed. It is an integrated one. In such a heat dissipation device having a laminated structure, the heat dissipation device is temporarily assembled with a brazing material sandwiched between the layers, and the temporary assembly is heated to be brazed together.

JP 2004-153075 A

  In general, brazing ceramic and metal is more difficult than metal-to-metal brazing and is less likely to be joined.

  The heat dissipation device has a ceramic insulating layer and an aluminum layer, and an aluminum layer and a metal heat sink, which have joint portions that are difficult to be brazed. The brazing material between the aluminum layer and the aluminum layer tends to flow toward the heat sink, and the brazing material may be insufficient.

  When the amount of the brazing material is increased in order to eliminate the shortage of the brazing material between the insulating layer and the aluminum layer, there is a risk that erosion by the brazing material may increase at these joint interfaces. Since the outflow amount to the heat sink side also increases, there is a possibility that the erosion to the heat sink by the outflow brazing material may occur. In addition, the aluminum layer is a stress relaxation layer between the insulating layer and the heat sink, and a punching metal with a large stress absorption capacity may be used. However, in the heat dissipation device using the punching metal, the hole is blocked by the leaked brazing material. There is. If the hole in the punching metal is blocked with a brazing material, the stress absorption capacity decreases. As described above, if the brazing property between the insulating layer and the aluminum layer is improved by increasing the amount of the brazing material, the harmful effect due to the surplus brazing material also increases.

  In view of the above-described technical background, the present invention provides a technique for brazing a heat dissipation device having a plurality of joints having difficulty in brazing without increasing the adverse effects caused by excess brazing material. With the goal.

  That is, the present invention has the configurations described in [1] to [9] below.

[1] A heat dissipation device in which a circuit layer for mounting an electronic element is laminated on one surface side of an insulating layer, and a heat sink is laminated on the other surface side through an aluminum layer, and these are integrated,
The insulating layer and the aluminum layer are joined by a first brazing material, and the aluminum layer and the heat sink are joined by a second brazing material,
A heat dissipation device, wherein the solidus temperature X ° C. of the first brazing material and the solidus temperature Y ° C. of the second brazing material satisfy a relationship of X <Y.

  [2] The heat radiation according to item 1, wherein the solidus temperature X ° C. of the first brazing material and the solidus temperature Y ° C. of the second brazing material satisfy a relationship of 0.5 <Y−X <30. apparatus.

  [3] The heat dissipating device according to item 1 or 2, wherein the solidus temperature X of the first brazing material is 500 to 565 ° C., and the solidus temperature Y of the second brazing material is 520 to 577 ° C.

  [4] The first brazing material is one selected from the group of an Al—Si—Zn alloy brazing material, an Al—Si—Cu based alloy brazing material, and an Al—Si—Cu—Zn based alloy brazing material. 4. The heat dissipation device according to any one of items 1 to 3.

  [5] The second brazing material is made of an Al—Si based alloy brazing material, an Al—Si—Zn based alloy brazing material, an Al—Si—Cu based alloy brazing material and an Al—Si—Cu—Zn based alloy brazing material. 5. The heat dissipation device according to any one of the preceding items 1 to 4, which is one type selected from the group.

  [6] The heat dissipation device according to item 4 or 5, wherein a Zn concentration in the Al—Si—Zn alloy brazing material and the Al—Si—Cu—Zn alloy brazing material is 1.5 to 20% by mass.

  [7] The heat radiating device according to item 4 or 5, wherein a Cu concentration in the Al—Si—Cu-based alloy brazing material and the Al—Si—Cu—Zn-based alloy brazing material is 0.3 to 15% by mass.

[8] A heat dissipation device in which an insulating layer, a first brazing material, an aluminum layer, a second brazing material, and a heat sink are temporarily stacked and temporarily assembled, and the temporary assembly is heated to braze the insulating layer, the aluminum layer, and the heat sink. A manufacturing method comprising:
The solidus temperature X ° C. of the first brazing material and the solidus temperature Y ° C. of the second brazing material satisfy the relationship X <Y,
In the brazing temperature profile, the temporary assembly is held in an intermediate temperature range not lower than the solidus temperature XC of the first brazing material and lower than the solidus temperature YC of the second brazing material. Manufacturing method of heat dissipation device.

  [9] The method for manufacturing a heat radiating device according to [8], wherein the holding time in the intermediate temperature range is 0.5 to 10 minutes.

  In the invention described in [1], the solidus temperature X ° C. of the first brazing material that joins the insulating layer and the aluminum layer that are difficult to be joined, and the second brazing material that joins the aluminum layer and the heat sink that are easy to join. The solidus temperature Y ° C. satisfies the relationship X <Y. Because of the relationship X <Y, the first brazing material is melted first in the initial stage of the brazing process, and only the first brazing material is melted until the solidus temperature Y ° C. of the second brazing material is reached. The first brazing material protruding from the joint interface is not connected to the second brazing material on the side surface of the aluminum layer. Since the second brazing material does not promote the outflow of the first brazing material unless it is connected to the first brazing material, the first brazing material is consumed for joining the insulating layer and the aluminum layer without being lost from the joining interface. When the brazing process proceeds and the solidus temperature YC of the second brazing material is reached, the second brazing material also starts to melt, and the first brazing material that has been melted flows toward the heat sink, or the first brazing material The brazing material is connected to the second brazing material, but at that time, an amount of brazing material necessary for joining the insulating layer and the aluminum layer is held at the joining interface, so that there is no shortage of the brazing material.

  In this way, since the two joints having a difficulty difference in brazability are well joined together, it is not necessary to supply an excessive amount of brazing material in anticipation of outflow, and erosion due to surplus brazing material can be suppressed. . Moreover, when a through-hole is provided in the aluminum layer, the through-hole is not blocked with an excess brazing material, and the stress absorption capacity is not reduced.

  According to the invention described in [2], the above-described effects can be obtained without requiring strict brazing temperature control.

  According to each invention described in [3], [4], [5], [6], and [7], two joints having a difference in difficulty in brazing are preferable in view of the materials of the insulating layer, the aluminum layer, and the heat sink. Can be joined.

  According to the invention described in [8], in the brazing temperature profile, the intermediate temperature of the temporary assembly is not less than the solidus temperature X ° C. of the first brazing material and less than the solidus temperature Y ° C. of the second brazing material. The first brazing material is melted before the second brazing material by being held in the region, and the joining of the insulating layer and the aluminum layer proceeds prior to the joining of the aluminum layer and the heat sink. Does not promote the outflow of the first brazing filler metal. For this reason, the first brazing material is consumed for joining the insulating layer and the aluminum layer without being lost from the joining interface. When the brazing process proceeds and the solidus temperature YC of the second brazing material is reached, the second brazing material also starts to melt, and the first brazing material that has been melted flows toward the heat sink, or the first brazing material The brazing material is connected to the second brazing material, but at that time, an amount of brazing material necessary for joining the insulating layer and the aluminum layer is held at the joining interface, so that there is no shortage of the brazing material.

  According to the invention described in [9], the second brazing material can be melted after sufficiently joining the insulating layer and the aluminum layer by the first brazing material.

It is sectional drawing of one Embodiment of the thermal radiation apparatus concerning this invention.

[Configuration of heat dissipation device]
FIG. 1 shows an embodiment of a heat dissipation device of the present invention in a cross section cut in a direction in which constituent members are laminated.

  In the heat dissipation device (1), a circuit layer (12) on which an electronic element (14) is mounted is laminated on one surface side of an insulating layer (11), and a heat sink is disposed on the other surface side via an aluminum layer (13). (20) are stacked and joined together. The circuit layer (12), the insulating layer (11), and the heat sink (13) are thermally coupled via the aluminum layer (13), and the heat generated by the electronic element (14) mounted on the circuit layer (12). Is exhausted by the heat sink (20).

  The heat dissipating device (1) includes a circuit layer (12), an insulating layer (11), an aluminum layer (13), and a heat sink (20), which are temporarily assembled with a brazing material disposed between the members. It is soldered together and then soldered with the electronic element (14). In the following description, the junction between the insulating layer (11) and the aluminum layer (13) is the first junction (31), and the junction between the aluminum layer (13) and the heat sink (20) is the second junction. (32), a joint between the insulating layer (11) and the circuit layer (12) is abbreviated as a third joint (33), and the first joint (31), the second joint (32), and the third The brazing materials for joining the joint portions (33) are referred to as a first brazing material (41), a second brazing material (42) and a third brazing material (43), respectively.

  Preferred materials for each layer constituting the heat dissipation device (1) are as follows.

  Examples of the material constituting the insulating layer (11) include ceramics such as aluminum nitride, aluminum oxide, silicon nitride, silicon carbide, and zirconium oxide. These ceramics are recommended not only because of their excellent electrical insulation, but also because they have good thermal conductivity and excellent heat dissipation.

  As the metal constituting the circuit layer (12), a metal having high conductivity and capable of being brazed or soldered to the insulating layer (11) is used, and particularly high-purity aluminum can be recommended.

  Since the aluminum layer (13) is a layer for relieving thermal stress generated at the bonding interface between the ceramic insulating layer (11) having high rigidity and the heat sink (20), a soft metal is used. High purity aluminum is particularly preferable. It is also preferable to use a punching metal having a plurality of circular through holes (13a) as a stress absorbing space, like the aluminum layer (13) in the illustrated example.

  As the metal constituting the heat sink (20), it is preferable to use a material excellent in lightness, strength maintenance, formability, and corrosion resistance. Al-Mn based alloys, Al-Fe based alloys and the like have these characteristics. Aluminum alloy can be recommended. If the heat sink (20) has a flat outer surface on the aluminum layer (13) side, it can be brazed in a large area with the aluminum layer (20) to obtain high heat dissipation performance. There is no limitation on the shape or internal shape. The heat sink (20) in the example shown in the figure is a refrigerant chamber (23) formed by combining an upper plate (21) having a bulging portion and a bottom plate (22) consisting of a flat plate, and an inner fin (24) is fitted and joined. It is. Other shapes of the heat sink include a flat plate, a heat sink in which fins are brazed to the other surface of the flat plate, a tube heat sink formed of a shape member having a hollow portion, and the like.

[Brazing of heat dissipation device]
The present invention is defined with respect to the solidus temperature of the first brazing material (41) and the second brazing material (42) of the three brazing materials described above.

  The first joint portion (31) and the second joint portion (32) are located on both sides of the aluminum layer (13), which are separated by the aluminum layer (13), and the distance is the thickness of the aluminum layer (13). Minutes. Since the side surface of the aluminum layer (13) is flat, the molten brazing material protruding from the bonding interface is in a state where it can travel along the side surface of the aluminum layer (13) without being blocked. In addition, the molten brazing material that protrudes from the joint interface into the through hole (13a) can also travel along the wall surface of the through hole (13a).

  Since the first joining portion (31) is a joining of different materials of ceramic and metal, it is less likely to be joined than the second joining portion (32) between the metals, and the joining takes time. For this reason, when the same brazing material is used for the first joint portion (31) and the second joint portion (32), the melted second brazing material (41) is consumed for joining in the brazing process. However, there is a time when the melted first brazing material (41) is in a state where it easily flows out from the joining interface because the holding power at the joining interface is weaker than that of the second brazing material (42). If such a state occurs in the initial stage of the brazing process, the first brazing material (41) is likely to flow out from the joining interface to the side surface of the aluminum layer (13) and the through hole (13a) without being consumed for joining. At this time, if the second brazing material (42) protrudes into the side surface of the aluminum layer (13) and the through hole (13a), the protruding second brazing material (42) and the first brazing material (41) May be connected on the side surface of the aluminum layer (13) and on the wall surface of the through hole (13a). In addition, as the amount of the second brazing material (42) protruding from the joining interface of the second joining portion (32) increases, the second brazing material (42) causes the side surface of the aluminum layer (13) to face the first joining portion (31). The amount that flows to the side increases, approaches the first joint (31), the second brazing material (42) is picked up by the first brazing material (41), and is connected to the first brazing material (41). It becomes easy. When both brazing filler metals are connected to form a braided streak, the first brazing filler metal (41), which has a weak holding power at the bonding interface, becomes the second brazing filler metal (42) as the priming water and the The outflow is promoted, and a larger amount of brazing material flows out from the joining interface than the first brazing material (41) flows out alone. As a result, the first joint portion (31) has insufficient brazing material, resulting in poor bonding.

  In the present invention, in order to prevent the second brazing material (42) from becoming the priming water flowing out of the first brazing material (41) at the initial stage of the brazing process, the solidus temperature X ° C. of the first brazing material (41) It is a requirement that the solidus temperature Y ° C. of the material (42) satisfies the relationship X <Y.

  In the brazing temperature profile, the actual temperature of the temporary assembly is increased until the brazing set temperature is reached. In this temperature profile, the first brazing material (41) having a low solidus temperature is melted first, and the joining of the first joining part (31), which is difficult to join, starts earlier than the second joining part (32). . Until the solidus temperature Y 2 C of the second brazing material (42) is reached, only the first brazing material (31) is melted and the second brazing material (42) is not melted. ) Even if the first brazing material (41) protrudes from the side surface of the aluminum layer (13) from the joining interface, the second brazing material (42) is not connected to the side surface. Since the second brazing filler metal (42) will not be the priming water for the first brazing filler metal (41) outflow unless it is connected to the first brazing filler metal (41), the first brazing filler metal (41) is lost from the joint interface. Without spending on joining. When the brazing process proceeds to reach the solidus temperature Y ° C. of the second brazing material (42), the second brazing material (42) also begins to melt. In the temperature range of the solidus temperature Y ° C. or higher of the second brazing material (42), the first brazing material (41) that has started melting and has proceeded to the melting flows to the second joint (32) side, or The first brazing material (41) may be connected to the second brazing material (42) protruding from the joining interface to the side surface of the aluminum layer (13), but at that time, it is necessary for joining the first joining portion (31). Since the amount of brazing material is held at the joining interface, there is no shortage of brazing material. In addition, since the melting of the second brazing material (42) is delayed, the amount of protrusion of the second brazing material (42) to the side surface of the aluminum layer (13) is small, and it is difficult to connect to the first brazing material (41). It is a factor. Also, the brazing property is good as well as the second joint portion (32), and the first brazing material (41) flowing to the second joint portion (32) side enters the joint interface of the second joint portion (32). Since it is used for joining, a sufficient amount of brazing material is supplied to the second joint portion (32) and brazed well.

  The aluminum layer (13) in the illustrated example has a through hole (13a) as a stress absorbing space, and the same phenomenon as that on the side surface occurs on the wall surface of the through hole (13a). That is, the priming action by the second brazing material (42) is performed in the temperature range where the solidus temperature of the first brazing material (41) is equal to or higher than the solidus temperature X ° C and lower than the solidus temperature Y ° C of the second brazing material (42). The first brazing material (41) required for joining is held at the joining interface of the first joining part (31) to prevent the first brazing through the through hole (13a) in the second joining part (32) as the brazing process proceeds. The material (41) is supplied.

  As described above, in the brazing temperature profile, the temperature range of the first brazing material (41) above the solidus temperature X ° C. and lower than the solidus temperature Y (° C.) of the second brazing material (42) is It is an intermediate temperature range in which only one brazing material (41) is melted. In the intermediate temperature range, the first joining portion (31) is joined prior to the second joining portion (32), and the second brazing material (42) serves as a priming water for the outflow of the first brazing material (41). There is no. In other words, before the second brazing material (42) starts to melt, the first joining portion (31) is joined until the first brazing material (41) flows out from the joining interface until no brazing material shortage occurs. If it advances, both the 1st junction part (31) and the 2nd junction part (32) can be joined favorably.

  According to the present invention, the first joint portion (31) that is difficult to be joined is brazed well because the first brazing material (41) is held at the joining interface at the initial stage of the brazing process. The second joint portion (31) is easily joined as well as the first brazing material (41) is supplied with the progress of the brazing process, so that the second joint portion (31) is brazed well. In this way, the two joint portions having a difficulty difference in brazability are well joined together. Further, since it is not necessary to supply an excessive amount of brazing material in anticipation of outflow to the first joint portion (31), erosion due to the surplus brazing material can be suppressed. Further, the through hole (13a) of the aluminum layer (13) is not blocked by the excess brazing material, and the stress absorption capacity is not reduced.

  In the third joint (33), the insulating layer (11) and the circuit layer (12) are joints of different materials, and are the joints that are difficult to be joined like the first joint (31). However, since the dimension of the insulating layer (11) is set larger than that of the circuit layer (12) in order to prevent a short circuit of the circuit layer (12), the third junction (33) has a large insulating layer (11). Thus, the communication between the first joint (31) and the second joint (32) is completely cut off. For this reason, even if it takes time to join the third joint portion (33), the third brazing material (43) is not lost from the joint interface. Therefore, it is not necessary to set the third brazing material (43) based on the relationship between the solidus temperature of the first brazing material (41) and the second brazing material (42), and the third brazing material (43) The selection should be made considering only the brazability between the insulating layer (11) and the circuit layer (12). In addition, the present invention does not limit the joining method of the insulating layer (11) and the circuit layer (12) to brazing, and includes the case of joining by soldering.

[Brazing materials and brazing conditions]
As described above, the condition for preventing the second brazing material (42) from being the priming water of the first brazing material (41) is that the first brazing material (41) starts to melt in the brazing temperature profile. The second brazing material (42) is in an unmelted state. Therefore, in the present invention, the condition of the first brazing material (41) and the second brazing material (42) is that the solidus temperature satisfies the relationship of X <Y. As long as the relationship of X <Y is satisfied, the composition and form of the brazing material are not limited.

  In the brazing temperature profile, the first brazing material (41) is the only temperature range where the solidus temperature of the first brazing material (41) is not lower than X ° C and lower than the solidus temperature of the second brazing material (42). Is an intermediate temperature range where melting begins. In the intermediate temperature range, the first joining portion (31) is joined prior to the second joining portion (32), and the second brazing material (42) serves as a priming water for the outflow of the first brazing material (41). There is no. In other words, before the second brazing material (42) starts to melt, the first joining portion (31) is joined until the first brazing material (41) flows out from the joining interface until no brazing material shortage occurs. If it advances, both the 1st junction part (31) and the 2nd junction part (32) can be joined favorably. From this viewpoint, preferable brazing materials and brazing conditions are as follows.

  The solidus temperature X ° C. of the first brazing material (41) and the solidus temperature Y ° C. of the second brazing material (42) satisfy the relationship of 0.5 <Y-X <30. preferable. When the solidus temperature difference (Y-X) is 0.5 ° C. or less, a temporary assembly is required to sufficiently advance the joining of the first joint (31) before the second brazing material (42) starts to melt. Must be maintained in a narrow temperature range. For this reason, since strict brazing temperature control is required, it is not preferable. On the other hand, when the solidus temperature difference (Y-X) is 30 ° C. or higher, the first brazing material (41) is excessively melted and eroded when the second brazing material (42) is melted. Absent. A particularly preferred solidus temperature relationship is 0.5 <Y-X <20.

  In view of the materials of the insulating layer (11), the aluminum layer (13), and the heat sink (20) described above, the solidus temperature X of the first brazing material (41) is 500 to 565 ° C. The solidus temperature Y of the material (42) is preferably 520 to 577 ° C. The solidus temperature X of the first brazing material (41) is more preferably 510 to 565 ° C, and the solidus temperature Y of the second brazing material (42) is more preferably 530 to 577 ° C.

  As the first brazing filler metal (41) and the second brazing filler metal (42) that satisfy the above-mentioned solidus temperature conditions, Zn and / or Al is added to the Al—Si based alloy brazing material or the Al—Si based alloy to lower the melting point. Examples include an Al—Si—Zn alloy brazing material to which Cu is added, an Al—Si—Cu alloy brazing material, and an Al—Si—Cu—Zn alloy brazing material. Of these brazing materials, preferable brazing materials as the first brazing material (41) having a low solidus temperature are Al-Si-Zn alloy brazing material, Al-Si-Cu alloy brazing material and Al-Si. -It is 1 type chosen from the group of a Cu-Zn type alloy brazing material. Also, brazing materials preferable as the second brazing material (421) having a high solidus temperature are Al—Si based alloy brazing material, Al—Si—Zn based brazing material, Al—Si—Cu based brazing material and Al—. This is one selected from the group of Si—Cu—Zn alloy brazing materials.

  Further, the Si concentration, Zn concentration, and Cu concentration in the brazing material are not limited, and can be set as appropriate so as to obtain a desired solidus temperature. A preferable Si concentration in the brazing material is 8 to 14% by mass, and a particularly preferable Si concentration is 9 to 12% by mass. Moreover, preferable Zn density | concentration is 1.5-20 mass%, and preferable Cu density | concentration is 0.3-15 mass%. However, since the workability decreases when the Zn concentration and the Cu concentration become high, when processing into a brazing material foil, it is preferable to set the Zn concentration to 10% by mass or less and the Cu concentration to 5% by mass or less. For vacuum brazing, it is preferable to use a brazing material in which Mg is added to the above composition. In order to enhance the fluidity of the brazing material, it is also preferable to use a brazing material in which Bi or Sr is added to the above composition.

  Moreover, the following composition can be illustrated as an example of the brazing filler metal having a solidus temperature of 500 ° C., 520 ° C., 565 ° C., and 577 ° C.

Solidus temperature 500 ° C: Al-10 mass% Si-15 mass% Cu-20 mass% Zn alloy Solidus temperature 520 ° C: Al-10 mass% Si-10 mass% Cu-15 mass% Zn alloy Solid phase Linear temperature 565 ° C .: Al-10 mass% Si-8 mass% Cu alloy, Al-10 mass% Si-6 mass% Zn alloy Solidus temperature 577 ° C .: Al-10 mass% Si alloy The first brazing material ( 41) and the shape of the second brazing material (42) are not limited in any way, they may be arranged at the joint as brazing material foil or brazing material powder, and the aluminum layer (13) may be composed of a brazing sheet. .

  In the brazing temperature profile, the intermediate temperature range, that is, holding in the temperature range of the first brazing material (41) above the solidus temperature X ° C and below the solidus temperature Y ° C of the second brazing material (42). The time is preferably 0.5 to 10 minutes. If it is less than 0.5 minutes, the joining of the first joint portion (31) is not sufficiently advanced, and the melting of the second brazing material (42) starts when the joining of the first joint portion (31) is insufficient. 1 There is a risk that the brazing filler metal (31) will flow out. On the other hand, if it is held for 10 minutes, the first joint portion (31) proceeds sufficiently, so even if it is held longer than 10 minutes, it does not contribute to further improvement of brazing. Holding times longer than necessary will increase the brazing time. A particularly preferable holding time is 1 to 8 minutes. Since the holding time may be X ° C. or more and less than Y ° C., the holding time may be fixed and held at a certain temperature within this temperature range, or held while raising the temperature so as not to exceed the temperature range. May be.

  The heat radiating device (1) shown in FIG. 1 was temporarily assembled by changing the brazing material, and a brazing test was performed.

[Components and brazing materials for heat dissipation devices]
The temporary assembly of the heat dissipating device (1) is composed of a common circuit layer (12), insulating layer (11), aluminum layer (13) and heat sink (20) in each example, and different brazing materials in each example.

  The circuit layer (12) is a flat plate of 28.3 mm × 28.3 mm × thickness 0.6 mm made of high-purity aluminum of 99.99% or more.

  The insulating layer (11) is a flat plate made of aluminum nitride and having a size of 30 mm × 30 mm × thickness 0.6 mm.

  The aluminum layer (13) is made of high-purity aluminum of 99.99% or more, and 13 through holes (13a) having a diameter of 2 mm are drilled on a flat plate of 28.3 mm × 28.3 mm × thickness 1.6 mm. Punched metal.

  The material of the top plate (21) and the bottom plate (22) of the heat sink (20) is a single-sided brazing sheet in which a brazing material made of an Al-10 mass% Si-1 mass% Zn alloy is clad on a core material made of A3003. The brazing sheet has a thickness of 1.0 mm and the brazing material has a cladding ratio of 5%. The upper plate (21) is formed by forming a bulging portion having a plan view of 50 mm × 50 mm on the brazing sheet by pressing and using the peripheral edge of the opening of the bulging portion as a joint portion for joining. The bottom plate (22) is a flat plate obtained by cutting the brazing sheet in accordance with the dimensions of the joint portion of the upper plate (21). The inner fin (24) is formed by bending a bare material made of A1100 having a thickness of 0.3 mm into a corrugated shape. The heat sink (20) is assembled by placing the upper plate (21) and the bottom plate (22) with the brazing material-side surfaces facing each other and loading the inner fin (24) in the refrigerant chamber (23).

  Table 1 shows a first brazing material (41) for joining the insulating layer (11) and the aluminum layer (13), and a second brazing material (42) for joining the aluminum layer (13) and the heat sink (20). A brazing material foil having a thickness of 20 μm was used. Table 1 shows the solidus temperature X, Y and the solidus temperature difference Y-X of the first brazing material (41) and the second brazing material (42). Further, the third brazing material (33) for joining the insulating layer (11) and the circuit layer (12) is common in each example, and an Al-10 mass% Si-1 mass% Mg alloy having a thickness of 40 μm. A brazing foil was used.

[Brazing test]
Circuit layer (12), third brazing material (43), insulating layer (11), first brazing material (41), aluminum layer (13), first brazing material (42), heat sink (20) in this order The heat dissipating device (1) was temporarily assembled, and then brazed by heating at 600 ° C. for 20 minutes in a vacuum. In this brazing temperature profile, it took 50 minutes for the actual temperature of the temporary assembly to rise from room temperature to 600 ° C., and 20 minutes after reaching 600 ° C. was maintained at 600 ° C. In the brazing temperature profile, the solid temperature was maintained in an intermediate temperature range that is not lower than the solidus temperature X ° C. of the first brazing material (41) and lower than the solidus temperature Y ° C. of the second brazing material (42). The time was the time shown in Table 1.

  For the brazed heat dissipation device (1), the first joint (31) between the insulating layer (11) and the aluminum layer (13) and the second joint (32) between the aluminum layer (13) and the heat sink (20). The joining state was examined by ultrasonic flaw detection to examine the joining area ratio, and evaluated according to the following criteria.

○: Joining area ratio is 95% or more Δ: Joining area ratio is 85% or more and less than 95% ×: Joining area ratio is less than 85%

Moreover, the 1st junction part (31) and the 2nd junction part (32) were observed, the excess degree (erosion) of brazing material was investigated, and the following reference | standard evaluated.
◯: Almost no erosion is observed. X: The erosion is intense. These evaluation results are also shown in Table 1.

  As shown in Table 1, it was confirmed that by selecting a brazing material based on the solidus temperature of the brazing material, it is possible to satisfactorily braze a heat radiating device having a difficulty in brazing.

  INDUSTRIAL APPLICATION This invention can be utilized for manufacture of the heat sink which laminated | stacked the insulating layer and the heat sink via the aluminum layer, and integrated these by brazing collectively.

1 ... Heat dissipation device
11… Insulating layer
12 ... Circuit layer
13 ... Aluminum layer
14 ... Electronic elements
20 ... heat sink
41 ... 1st brazing filler metal
42 ... Second brazing material
43 ... Third brazing material

Claims (9)

A circuit layer for mounting an electronic element is laminated on one surface side of the insulating layer, and a heat sink is laminated on the other surface side through an aluminum layer.
The insulating layer and the aluminum layer are joined by a first brazing material, and the aluminum layer and the heat sink are joined by a second brazing material,
A heat dissipation device, wherein the solidus temperature X ° C. of the first brazing material and the solidus temperature Y ° C. of the second brazing material satisfy a relationship of X <Y.   2. The heat dissipation device according to claim 1, wherein the solidus temperature X ° C. of the first brazing material and the solidus temperature Y ° C. of the second brazing material satisfy a relationship of 0.5 <Y−X <30.   The heat dissipation device according to claim 1 or 2, wherein the solidus temperature X of the first brazing material is 500 to 565 ° C, and the solidus temperature Y of the second brazing material is 520 to 577 ° C.   The first brazing material is one selected from the group consisting of an Al-Si-Zn alloy brazing material, an Al-Si-Cu alloy brazing material, and an Al-Si-Cu-Zn alloy brazing material. The heat radiating device according to any one of?   The second brazing material is selected from the group consisting of an Al—Si based brazing material, an Al—Si—Zn based brazing material, an Al—Si—Cu based brazing material, and an Al—Si—Cu—Zn based brazing material. The heat dissipating device according to claim 1, wherein the heat dissipating device is one type.   The heat dissipation device according to claim 4 or 5, wherein a Zn concentration in the Al-Si-Zn-based alloy brazing material and the Al-Si-Cu-Zn-based alloy brazing material is 1.5 to 20% by mass.   The heat dissipation device according to claim 4 or 5, wherein a Cu concentration in the Al-Si-Cu-based alloy brazing material and the Al-Si-Cu-Zn-based alloy brazing material is 0.3 to 15% by mass. In the method of manufacturing a heat dissipation device, the insulating layer, the first brazing material, the aluminum layer, the second brazing material, and the heat sink are stacked and temporarily assembled, and the temporary assembly is heated to braze the insulating layer, the aluminum layer, and the heat sink. There,
The solidus temperature X ° C. of the first brazing material and the solidus temperature Y ° C. of the second brazing material satisfy the relationship X <Y,
In the brazing temperature profile, the temporary assembly is held in an intermediate temperature range not lower than the solidus temperature XC of the first brazing material and lower than the solidus temperature YC of the second brazing material. Manufacturing method of heat dissipation device.   The method for manufacturing a heat dissipation device according to claim 8, wherein a holding time of the intermediate temperature range is 0.5 to 10 minutes.

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