JP7338440B2 - Insulated circuit board with heat sink and electronic equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to an insulated circuit board with a heat sink and an electronic device using the same.

As an insulating circuit board, a circuit layer is formed on one surface of an insulating layer made of a ceramic substrate such as aluminum nitride, and a heat sink is bonded to the other surface via a metal layer. Are known.
For example, the insulated circuit board with a heat sink disclosed in Patent Document 1 has a circuit layer formed on one surface of a ceramic substrate and a heat sink bonded to the other surface of the ceramic substrate via a heat dissipation layer. , the heat sink is formed with a housing recess in which the insulated circuit board is housed.

JP 2016-181549 A

By the way, when the insulating circuit board disclosed in Patent Document 1 is joined to the heat sink, a brazing material is sandwiched between the insulating circuit board and the heat sink and heated while being pressed. As such a brazing material, an aluminum-based brazing material is used. In particular, when an aluminum alloy clad material containing magnesium (Mg) is used for joining, joining can be performed at a relatively low temperature.

However, when an aluminum alloy clad material containing Mg is used, surplus molten solder creeps up from the bottom of the accommodation recess in the heat sink to the inner side surface of the accommodation recess and reaches the top surface of the peripheral wall portion located on the outer periphery of the accommodation recess. Sometimes. The molten brazing filler metal crawling up on the inner side surface and the top surface of the peripheral wall solidifies on these surfaces. In this case, the solidified molten brazing filler metal (hereinafter referred to as residual brazing filler metal) becomes an Al—Mg alloy, Mg diffuses on the surface, and the oxide coating becomes a porous coating containing MgO. , epoxy resin, etc.), the adhesion between the resin material and the peripheral wall is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an insulating circuit board with a heatsink and an electronic device that can improve resin adhesion of the peripheral wall of the heatsink in the insulating circuit board with a heatsink.

The insulated circuit board with a heat sink of the present invention includes a circuit layer formed on one surface of a ceramic substrate and a metal layer formed on the other surface of the ceramic substrate; An insulated circuit board with a heat sink in which a housing recess for housing at least a part of the insulated circuit board is formed in a central portion thereof, and the bottom surface of the housing recess is brazed to the heat sink, the peripheral wall of the housing recess A solder reservoir recess is formed in at least a part of the inner side surface, and the solder reservoir recess is located closer to the bottom surface of the housing recess than the ceramic substrate.

On the inner side surface of the peripheral wall portion, if the solder reservoir recess is formed on the opposite side of the ceramic substrate to the bottom surface of the accommodation recess (upper side of the ceramic substrate), the area where molten solder creeps up in the peripheral wall portion (remaining solder is fixed area) becomes wider, resulting in lower resin adhesion.
In general, the peripheral edge of the ceramic substrate is formed so as to protrude outward from the peripheral edge of the circuit layer or the metal layer. Therefore, when the housing recess is molded with a resin material, the stress on the resin material is the highest at the periphery of the ceramic substrate during thermal cycles. In addition, since the area where the residual solder is fixed in the peripheral wall has lower resin adhesion than the area where the residual solder is not fixed, the solder pool recess is opposed to the peripheral edge of the ceramic substrate on the inner side surface of the peripheral wall. If it is formed at the position where the resin adhesion is low, the part where the stress is most applied is close to the part where the resin adhesion is low, so that the molded resin material is easily peeled off.

In the present invention, since the molten solder is accumulated in the brazing reservoir recess located closer to the bottom surface of the housing recess than the ceramic substrate, the region on the inner side surface of the peripheral wall portion in which the molten solder creeps up can be reduced. Therefore, it is possible to improve resin adhesion when the housing recess is molded with a resin material. In particular, it is useful when the solidified molten wax (residual wax) contains an element such as magnesium that reduces resin adhesion. In addition, since the accommodation recess is not formed at the same height as the peripheral portion of the ceramic substrate, the portion where the stress to the resin is the highest and the portion where the resin adhesion is low do not come close to each other. It can suppress peeling.

As a preferred aspect of the insulated circuit board with a heat sink of the present invention, the bottom surface of the solder reservoir recess is preferably aligned with the bottom surface of the accommodation recess.
In the above aspect, surplus molten solder generated when the insulated circuit board and the heat sink are joined flows along the bottom surface of the accommodation recess and directly flows into the solder reservoir recess, and is accumulated in the solder reservoir recess. Therefore, it is possible to reliably suppress the molten brazing filler metal from creeping up to the inner side surface of the peripheral wall portion. Further, since the remaining brazing filler metal is fixed only to a part of the inner side surface of the peripheral wall portion, it is possible to further improve resin adhesion when the housing recess is molded with a resin material.

As a preferred aspect of the insulated circuit board with a heat sink of the present invention, the solder reservoir recess may be formed along the entire circumference of the inner side surface of the peripheral wall portion.
In the above-described aspect, since the brazing reservoir recess is formed along the entire circumference of the inner side surface of the peripheral wall portion, excess brazing material generated when the bottom surface of the accommodation recess in the heat sink and the metal layer of the insulated circuit board are joined using a brazing material. Molten brazing can be reliably accumulated in the brazing reservoir concave portion, and the resin adhesion of the peripheral wall portion of the heat sink can be further enhanced.

An electronic device according to the present invention includes the insulating circuit board with a heat sink, an electronic component provided on the circuit layer of the insulating circuit board, and a resin material molded on the electronic component and in the housing recess. .

In the present invention, by reducing the area where the remaining solder is fixed on the inner side surface of the peripheral wall of the heat sink, it is possible to improve the adhesion between the inner side surface of the housing recess and the resin, thereby providing a highly reliable electronic device. can.

ADVANTAGE OF THE INVENTION According to this invention, the resin adhesion property of the peripheral wall part of a heat sink in an insulated circuit board with a heat sink can be improved, and an electronic device with high reliability can be provided.

1 is a cross-sectional view showing a power module using an insulated circuit board with a heat sink according to a first embodiment of the present invention; FIG. It is an enlarged view which expands and shows a part of insulation circuit board with a heat sink shown in FIG. FIG. 3 is a cross-sectional view for explaining the method of manufacturing the insulating circuit board with a heat sink shown in FIG. 1, and shows a state before bonding the insulating circuit board and the heat sink. FIG. 3 is a cross-sectional view for explaining the method of manufacturing the insulating circuit board with the heat sink shown in FIG. 1, and shows a state after bonding the insulating circuit board and the heat sink. FIG. 2 is a plan view of an insulating circuit board with a heat sink according to the embodiment; It is an exploded perspective view showing an example of attachment to a case of a power module in the above-mentioned embodiment. FIG. 4 is a cross-sectional view showing a power module using an insulated circuit board with a heat sink according to a second embodiment of the present invention; It is a figure which expands and shows a part of insulation circuit board with a heat sink which concerns on 3rd Embodiment of this invention. FIG. 11 is a side view showing a side surface of the insulated circuit board with a heat sink according to the third embodiment; It is a figure which expands and shows a part of insulation circuit board with a heat sink which concerns on 4th Embodiment of this invention. It is a side view which shows the side surface of the insulated circuit board with a heat sink which concerns on the said 4th Embodiment.

[First embodiment]
A first embodiment of the present invention will be described below with reference to the drawings.

[Schematic Configuration of Insulated Circuit Board with Heat Sink]
As shown in FIG. 1, an insulating circuit board 1 with a heatsink according to the present invention is formed by joining a fin-integrated heat sink 20 having a plurality of fins erected to an insulating circuit board 10 .

[Configuration of power module]
Then, an electronic component 30 such as a semiconductor chip is mounted on the surface of the insulating circuit board 1 with a heat sink, and a resin material 60 is molded thereon to manufacture the power module 100 (electronic device).
The power module 100 including the fin-integrated heat sink 20 is used while attached to a case 40 as shown in FIG. 5, for example. The case 40 is formed with an opening 41 for mounting the plurality of pin-shaped fins 25 in an inserted state, and a packing accommodating groove 42 is formed so as to surround the opening 41 . A threaded hole 43 is formed outside the packing receiving groove 42 , and the heat sink 20 is inserted into the opening 41 by arranging the heat sink 20 so that the pin-shaped fins 25 face downward. 50, and fixed by screwing.
In the example shown in FIG. 5, two insulated circuit boards 1 (power modules 100) with heat sinks are attached, and as indicated by white arrows, a cooling medium is circulated and inserted inside the case 40. The pin-like fins 25 in the state are cooled.

[Configuration of insulation circuit board]
An insulating circuit board 10 constituting an insulating circuit board with a heat sink includes a ceramic substrate 11, a circuit layer 12 formed on one surface of the ceramic substrate 11, and a metal layer 13 formed on the other surface of the ceramic substrate 11. Prepare.
The ceramic substrate 11 is an insulating material that prevents electrical connection between the circuit layer 12 and the metal layer 13, and is made of, for example, aluminum nitride (AlN), silicon nitride ( _Si3N4 ), or the like _. is formed in The ceramic substrate 11 is formed slightly larger than the circuit layer 12 and the metal layer 13, and has a plate thickness of 0.2 mm to 1.2 mm.

[Configuration of circuit layer]
The circuit layer 12 is formed in a rectangular plate shape slightly smaller than the ceramic substrate 11 . In the example shown in FIG. 1, the circuit layer 12 is composed of two sub-circuit layers, on which electronic components 30 are respectively arranged. The circuit layer 12 is not limited to two small circuit layers, and may be composed of three or more small circuit layers, or may be composed of one circuit layer.
Such a circuit layer 12 includes a first circuit layer 121 bonded to the ceramic substrate 11 and a second circuit layer 122 bonded to the top surface of the first circuit layer 121 .

Of these, the first circuit layer 121 is made of pure aluminum with a purity of 99% by mass or more, and according to the JIS standard, pure aluminum in the 1000s, especially 1N90 (purity of 99.9% by mass or more: so-called 3N aluminum) or 1N99 (purity 99.99% by mass or more: so-called 4N aluminum) can be used. On the other hand, for the second circuit layer 122, an aluminum alloy such as A6063 series is used. For example, the thickness of the first circuit layer 121 is set to 0.4 mm to 1.6 mm, and the thickness of the second circuit layer 122 is set to 0.5 mm to 1.5 mm.

[Structure of metal layer]
The metal layer 13 is formed in a rectangular shape slightly smaller than the ceramic substrate 11 . Pure aluminum or an aluminum alloy with a purity of 99% by mass or more is used for the metal layer 13, and aluminum in the 1000s according to the JIS standard, particularly 1N99 (purity of 99.99% by mass or more: so-called 4N aluminum) can be used. . For example, the thickness of the metal layer 13 is set to 0.4 mm to 1.6 mm.

[Heat sink configuration]
The heat sink 20 joined to the insulating circuit board 10 is made of a plate material made of an aluminum alloy such as A6063 series. A housing recess 22 that houses at least a portion of the insulating circuit board 10 is formed in the central portion 21 of the heat sink that is joined to the metal layer 13, and a thick portion is left on the outer peripheral side of the housing recess 22. A peripheral wall portion 23 is formed. The metal layer 13 of the insulating circuit board 10 is laminated on the bottom surface of the housing recess 22 via an aluminum-based brazing filler metal foil 14 (see FIG. 3). A heat sink 20 is bonded to 10 .
For example, the central portion 21 of the heat sink 20 is 77 mm×67 mm in plan view, the outer diameter of the peripheral wall portion 23 is 100 mm×80 mm in plan view, and the insulation circuit board 10 is 75 mm×65 mm in plan view. .

Also, the heat sink 20 is formed so that the thickness dimension of the central portion 21 (the thickness dimension of the bottom portion of the accommodation recess 22 ) is thinner than the thickness dimension of the peripheral wall portion 23 . In this embodiment, the heat sink 20 is formed of a plate material made of an A6063 series aluminum alloy and has a total thickness of 2.1 mm to 6.8 mm, the peripheral wall portion 23 has a thickness of 2.1 mm to 6.8 mm, and the bottom surface of the housing recess 22 is 2.1 mm to 6.8 mm. The thickness dimension of the portion is set to 0.5 mm to 1.5 mm. A plurality of pin-shaped fins 25 are erected on the lower surface 21b of the central portion 21 of the heat sink 20. The tip positions of the pin-shaped fins 25 are aligned on the horizontal plane, and the standing height from the surface of the lower surface 21b is substantially equal. It is formed to be

Furthermore, a brazing reservoir recess 231 is formed in the inner side surface 230 of the peripheral wall portion 23 of the housing recess 22 of the heat sink 20 . As shown in FIGS. 1 and 2, the brazing reservoir recess 231 is positioned below the ceramic substrate 11 on the inner side surface 230 (on the bottom surface side of the accommodation recess 22 relative to the ceramic substrate 11).

Further, as shown in FIG. 5, the brazing reservoir recess 231 is formed by a groove formed over the entire circumference of the inner side surface 230 of the peripheral wall portion 23 . Further, the vertical width w1 of the brazing reservoir recess 231 is formed larger than the thickness of the brazing material foil 14 (see FIG. 3) used when joining the insulated circuit board 10 and the heat sink 20. For example, the thickness is It is set to 0.05 mm to 0.5 mm. If the vertical width w1 of the brazing pool recess 231 is smaller than the thickness of the brazing filler metal foil 14, there is a possibility that the surplus brazing filler metal cannot be held.
In addition, since the brazing reservoir recess 231 needs to store surplus molten solder generated when brazing the insulating circuit board 10 to the heat sink 20, its depth h1 is set to, for example, 0.05 mm to 10 mm. It is

For example, the brazing foil 14 shown in FIG. 01 mm, the volume of the brazing foil 14 required for the above joining is 0.01·X·Y mm ³ . In this case, when the thickness of the brazing filler metal foil 14 is 0.03 mm, the volume of the surplus brazing filler metal is 0.02·X·Y mm ³ . Therefore, it is preferable that the volume of the brazing pool recess 231 is 0.02·X·Y mm ³ or more.
In this case, if the brazing foil 14 with a thickness of 0.03 mm, which is larger than the thickness of the brazing foil required for joining, is used, the minimum required thickness of 0.01 mm is used. This is because the bonding between the insulating circuit board 10 and the heat sink 20 may not be stable due to misalignment or the like, and the bonding rate may decrease.
Since the volume of the brazing pool recess 231 is set as described above, as shown in FIG. The wax reliably flows and solidifies.

In addition, as shown in FIG. 6, for example, fastening holes 26 are formed in the outer peripheral edge of the heat sink 20 for screwing when attaching the heat sink 20 to various devices such as a case 40 .
Further, the shape of the fins erected on the heat sink 20 is not particularly limited, and in addition to the pin-shaped fins 25 as in the present embodiment, diamond-shaped fins, strip-shaped fins, or the like can be formed.

The electronic component 30 that constitutes the power module 100 is not necessarily limited, but is formed on the Ni plating (not shown) formed on the surface of the circuit layer 12. It is joined using a solder material such as a system, Sn--Ag system, Sn--Cu system, Sn--Sb system, or Pb--Sn system. Further, the electronic component 30 and the terminal portion of the circuit layer 12 are connected by a bonding wire (not shown) made of aluminum.

[Manufacturing method of insulated circuit board with heat sink]
Next, a method for manufacturing the insulating circuit board 1 with a heat sink according to this embodiment will be described.
The manufacturing method includes an insulating circuit board forming step of joining a circuit layer 12 and a metal layer 13 to a ceramic substrate 11 to form an insulating circuit board 10, and a heat sink joining step of joining a heat sink 20 to the insulating circuit board 10. . The order of steps will be described below.

(Insulated circuit board forming process)
The first circuit layer 121, the ceramic substrate 11, and the metal layer 13 are respectively made of Al--Si-based, Al--Ge-based, Al--Cu-based, Al--Mg-based, Al--Mn-based, or Al--Si--Mg-based brazing filler metals. By laminating the laminate via foil, heating the laminate while pressurizing it in the laminating direction, and then cooling it, the first circuit layer 121 is formed on one surface 11a of the ceramic substrate 11, and the metal layer is formed on the other surface 11b. 13 are joined.
The bonding conditions at this time are not necessarily limited. A minute or less is preferred.

Then, the first circuit layer 121 and the second circuit are laminated on the first circuit layer 121 via an aluminum-based brazing filler metal foil, heated while being pressed in the lamination direction, and then cooled. It strongly bonds with the layer 122 . Al-Si-based or Al-Si-Mg-based brazing filler metal foils, for example, can be used as this brazing filler metal foil. Preferably, Al-Si-Mg-based brazing filler metal ( As an example, it is preferable to use an aluminum alloy clad material in which Al-10.5 mass % Si-1.5 mass % Mg) is formed. By using such a clad material, the second circuit layer 122 made of an aluminum alloy having a relatively low solidus temperature can be joined at a relatively low temperature. The pressure in the stacking direction is preferably 0.1 MPa to 0.5 MPa, and the heating temperature is maintained at 590° C. or higher and 615° C. or lower for 3 minutes or longer and 20 minutes or shorter.
As a result, the circuit layer 12 (the first circuit layer 121 and the second circuit layer 122) is formed on one surface of the ceramic substrate 11, and the insulating circuit board 10 having the metal layer 13 formed on the other surface is formed. .

(Heat-sink bonding process)
Then, as shown in FIG. 3, an aluminum-based brazing filler metal foil 14 is interposed between the lower surface of the metal layer 13 of the insulated circuit board 10 and the bottom surface (central portion 21) of the housing recess 22 of the heat sink 20, and The metal layer 13 and the heat sink 20 are joined by heating while being pressurized to . As the aluminum-based brazing filler metal foil 14, for example, an Al-Si-based or Al-Si-Mg-based brazing foil can be used. Therefore, it is preferable to use an aluminum alloy clad material in which Al--Si--Mg brazing filler metal is formed on both sides of an aluminum alloy such as A3003.
Thereby, the heat sink 20 is joined to the insulating circuit board 10, and the insulating circuit board 1 with the heat sink shown in FIG. 4 is formed.
The pressure in the stacking direction is preferably 0.1 MPa to 0.5 MPa, and the heating temperature is maintained at 590° C. or higher and 615° C. or lower for 3 minutes or longer and 20 minutes or shorter.

Note that the bonding of the first circuit layer 121 and the second circuit layer 122 and the heat sink bonding process can be performed at the same time. In this case, it is preferable to use the same aluminum-based brazing filler metal foil 14 . That is, the second circuit layer 122 is laminated on the first circuit layer 121 via the aluminum-based brazing filler metal foil 14 for the joined body of the first circuit layer 121, the ceramic substrate 11, and the metal layer 13, and The first circuit layer 121 and the second circuit layer 122 are joined by heating while applying pressure to the laminate in the lamination direction. At the same time, the heat sink 20 and the metal layer 13 can be joined to manufacture the insulated circuit board 1 with the heat sink. The pressure in the stacking direction is preferably 0.1 MPa to 0.5 MPa, and the heating temperature is maintained at 590° C. or higher and 615° C. or lower for 3 minutes or longer and 20 minutes or shorter.

Then, an electronic component 30 such as a semiconductor chip is mounted on the surface of the circuit layer 12 of the insulating circuit board 1 with a heat sink manufactured by the manufacturing method described above, and a resin material 60 is molded thereon, whereby the power module 100 is formed. manufactured.

Here, in the heat sink bonding step, when the insulating circuit board 10 is bonded to the heat sink 20 using the aluminum-based brazing filler metal foil 14 , surplus molten solder flows from the bottom surface of the accommodation recess 22 in the heat sink 20 to the inner side surface 230 of the peripheral wall portion 23 . crawl up. In particular, when the aluminum-based brazing filler metal foil contains Mg, or when the above-mentioned aluminum alloy clad material such as A3003, in which Al-Si-Mg-based brazing filler metal is formed on both sides, is used, the brazing filler metal is likely to melt, such creeping up occurs remarkably.
In the inner side surface 230 of the peripheral wall portion 23, the resin material 60 is injected into the housing recess 22 because the area to which the remaining solder 14a is fixed has lower resin adhesion than the area to which the remaining solder 14a is not fixed. If they are molded together, the adhesion between the resin material 60 and the peripheral wall portion 23 is lowered. In particular, when the aluminum-based brazing filler metal foil 14 contains a large amount of Mg, the Mg diffuses on the surface of the remaining brazing filler metal 14a, and the oxide film becomes a porous film containing MgO. is injected and molded, the adhesion between the resin material 60 and the peripheral wall portion 23 is further reduced.

In this embodiment, since the brazing reservoir recess 231 is formed on the inner side surface 230, as shown in FIG. Excess molten brazing material generated during joining using 14 accumulates in the brazing reservoir recess 231 . Then, when the heating of the laminate is completed and it is cooled, the molten solder solidifies to become residual solder 14a. It is fixed within the recess 231 .

In this regard, if the brazing reservoir recess 231 is formed on the inner side surface 230 of the peripheral wall 23 on the opposite side of the ceramic substrate 11 to the bottom surface of the accommodation recess 22 (above the ceramic substrate 11), the melting of the peripheral wall 23 will occur. Since the region where the solder creeps up becomes wider, the resin adhesion is lowered.
In addition, in this embodiment, the peripheral edge of the ceramic substrate 11 is formed to protrude outward from the peripheral edge of the circuit layer 12 and the metal layer 13 . Therefore, when the accommodation recess 22 is molded with the resin material 60, the stress on the resin material 60 is the highest at the peripheral edge of the ceramics substrate 11 during the cooling/heating cycle. In addition, since the region of the peripheral wall portion 23 to which the remaining brazing filler metal 14 a is fixed has lower resin adhesion than the region to which the remaining brazing filler metal 14 a is not fixed, the solder reservoir recess 231 is formed by the ceramics on the inner side surface 230 of the peripheral wall portion 23 . If it is formed at a position facing the peripheral portion of the substrate 11, the portion with low resin adhesion and the portion where the stress is most applied are close to each other, so that the molded resin material 60 is easily peeled off.
For this reason, in this embodiment, a brazing reservoir recess 231 is formed below the ceramic substrate 11 in the inner side surface 230 of the peripheral wall portion 23 .

In the insulated circuit board 1 with a heat sink of the present embodiment, the molten solder accumulates in the brazing reservoir recess 231 located closer to the bottom surface of the accommodating recess 22 than the ceramic substrate 11 on the inner side surface 230 of the peripheral wall 23 . The area on the inner side surface 230 where the molten solder creeps up can be made smaller. Therefore, even if the remaining brazing filler metal 14 a contains magnesium, which reduces the resin adhesion, the resin adhesion can be improved when the housing recess 22 is molded with the resin material 60 . In addition, since the solder reservoir recess 231 is not formed at the same height as the peripheral portion of the ceramic substrate 11, the residual solder 14a is fixed at a position away from the portion of the ceramic substrate 11 where the stress on the resin material 60 is the highest. Therefore, it is possible to suppress peeling of the resin material from the accommodation recess 22 . Furthermore, since the brazing filler metal pooling recess 231 is formed along the entire circumference of the inner side surface 230 of the peripheral wall portion 23 , surplus molten solder can be reliably stored in the brazing filler metal pooling recess 231 .
Further, in the power module 100 using the insulated circuit board 1 with a heat sink, the area where the remaining solder 14a is fixed on the inner side surface 230 of the peripheral wall portion 23 is reduced, so that the inner side surface 230 of the peripheral wall portion 23 and the resin are in close contact with each other. Therefore, it is possible to provide a highly reliable power module.
In addition, since the solder reservoir recess 231 is formed on the inner side surface 230 of the peripheral wall portion 23, the melted solder does not crawl up to the upper surface 24 of the peripheral wall portion 23, so that the external appearance can also be improved.

[Second embodiment]
FIG. 7 is a cross-sectional view showing an insulating circuit board 1A with a heat sink according to the second embodiment. In the following description, the same or substantially the same configurations as those of the first embodiment are assigned the same numbers, and descriptions thereof are omitted or simplified.
In the present embodiment, the solder reservoir recess 231A is formed at the end of the housing recess 22 on the inner side surface 230 of the peripheral wall 23 on the bottom side. Specifically, the bottom surface of the accommodation recess 22 and the bottom surface of the solder pool recess 231A are aligned. Therefore, excess molten solder generated when the insulating circuit board 10 and the heat sink 20 are joined flows along the bottom surface of the housing recess 22 and directly flows into the solder reservoir recess 231A, and is accumulated in the solder reservoir recess 231A. will be

Here, when the solder reservoir recess 231 is formed in the intermediate portion of the inner side surface 230 of the peripheral wall portion 23 (the intermediate portion below the ceramic substrate 11) as in the first embodiment, the solder in the inner side surface 230 The remaining solder 14a is fixed in the region until reaching the reservoir recess 231. As shown in FIG.
On the other hand, in the present embodiment, the brazing filler metal pooling recess 231A is formed at the bottom-side end portion of the inner side surface 230 of the peripheral wall portion 23, so that it is possible to reliably suppress the molten solder from creeping up the inner side surface 230. Further, since the remaining solder 14a is not fixed to most of the inner side surface 230, the resin adhesion when the resin material 60 is molded inside the housing recess 22 can be further improved.

[Third Embodiment]
FIG. 8 is a cross-sectional view showing an enlarged part of an insulating circuit board 1B with a heatsink according to the third embodiment, and FIG. 9 is a side view showing a side of the insulating circuit board 1B with a heatsink according to the third embodiment. It is a diagram.
In this embodiment, as shown in FIG. 8, the brazing reservoir recess 231B is formed closer to the bottom surface of the accommodation recess 22 than the ceramic substrate 11 in the inner side surface 230 of the peripheral wall 23, as in the first embodiment. . As shown in FIG. 9, the solder reservoir recess 231B is composed of a plurality of (for example, 20) elongated grooves. h1 is set to 5 mm. Each of these plurality of grooves is intermittently arranged at predetermined intervals, and the interval w3 between adjacent grooves is, for example, 0.05 mm to 10 mm. In addition, the total volume of the plurality of grooves forming the brazing pool recess 231B is set larger than the volume of surplus molten brazing solder generated when the insulated circuit board 10 and the heat sink 20 are joined together.

For this reason, in this embodiment as well, surplus molten solder generated when bonding the insulated circuit board 10 and the heat sink 20 flows along the bottom surface and the peripheral wall portion 23 of the housing recess 22 and flows through the solder reservoir recess 231B (a plurality of grooves). ) and is accumulated in the brazing reservoir recess 231B, the region on the inner side surface 230 of the peripheral wall portion 23 where the molten brazing material creeps up can be reduced.

[Fourth Embodiment]
FIG. 10 is a cross-sectional view showing an enlarged part of an insulating circuit board 1C with a heatsink according to the fourth embodiment, and FIG. 11 is a side view showing a side of the insulating circuit board 1C with a heatsink according to the fourth embodiment. It is a diagram.
In this embodiment, as shown in FIG. 10, the brazing reservoir recess 232 is formed closer to the bottom surface of the accommodation recess 22 than the ceramic substrate 11 in the inner side surface 230 of the peripheral wall portion 23 . As shown in FIG. 11, the solder reservoir recess 232 is composed of a plurality of (for example, 32) through-holes, and the diameter w1 of one through-hole is set to 0.2 mm, for example. Each of the plurality of through-holes is intermittently arranged at predetermined intervals, and the interval w4 between adjacent through-holes is, for example, 0.05 mm to 10 mm.
In the present embodiment, since the brazing reservoir recess 232 is composed of a plurality of through holes, the sum of the volumes of the plurality of through holes is equal to the surplus generated when the insulated circuit board 1 and the heat sink 20 are joined together. It need not be larger than the volume of molten braze.

For this reason, in the present embodiment, surplus molten solder generated when bonding the insulated circuit board 10 and the heat sink 20 flows along the bottom surface and the peripheral wall portion 23 of the housing recess 22 and flows through the solder reservoir recess 232 (a plurality of through-holes). ) and accumulates in the brazing reservoir recess 232, or flows out to the outer peripheral surface side of the peripheral wall portion 23, so that the region on the inner side surface 230 of the peripheral wall portion 23 where the molten solder creeps up can be reduced.

In addition, detailed configurations are not limited to those of the embodiments, and various modifications can be made without departing from the scope of the present invention.
For example, in each of the above-described embodiments, the second circuit layer 122 is made of an aluminum alloy such as A6063 series. Moreover, although the circuit layer 12 is provided with the first circuit layer 121 and the second circuit layer 122, the circuit layer 12 is not limited to this, and may have a single-layer structure made of pure aluminum or an aluminum alloy.

Further, in the above embodiment, the metal layer 13 has a one-layer structure made of pure aluminum or an aluminum alloy. may In this case, the first metal layer and the second metal layer may have the same composition as the first circuit layer 121 and the second circuit layer 122, or the first metal layer may be formed of pure aluminum or an aluminum alloy, and the second metal layer may be made of copper or a copper alloy.

In the third and fourth embodiments, the solder pool recesses 231B and 232 are formed at the same positions as in the first embodiment. and the bottom surface of the housing recess 22 may be formed to coincide with each other.

In the above-described embodiments, the power module 100 is illustrated as an electronic device using the insulated circuit boards 1, 1A, 1B, 1C with heat sinks. For example, it can also be applied to other electronic devices such as LED modules.

1 1A 1B 1C Insulated circuit board with heat sink 10 Insulated circuit board 11 Ceramics board 12 Circuit layer 121 First circuit layer 122 Second circuit layer 13 Metal layer 14 Aluminum-based brazing filler metal foil 14a Remaining brazing filler metal 20 Heat sink 21 Center part 22 Accommodating recess 23 Peripheral wall portion 230 Inner side surface 231 231A 231B Solder pool recess 232 Solder pool recess 24 Upper surface 25 Pin-shaped fin 26 Fastening hole 30 Electronic component 40 Case 41 Opening 42 Packing accommodation groove 43 Screw hole 50 Packing 60 Resin material 100 Power module (electronic device )

Claims (4)

An insulated circuit board comprising a circuit layer formed on one side of a ceramic substrate and a metal layer formed on the other side of the ceramics substrate, and at least one of the metal layer and the insulated circuit board in the center. An insulated circuit board with a heat sink in which a bottom surface of the housing recess in a heat sink formed with a housing recess for housing a part is brazed,
A solder reservoir recess is formed in at least a part of an inner side surface of a peripheral wall portion of the accommodation recess, and the solder reservoir recess is positioned closer to the bottom surface of the accommodation recess than the ceramic substrate. Insulated circuit board with heatsink. 2. The insulated circuit board with a heat sink according to claim 1, wherein the bottom surface of said solder reservoir recess matches the bottom surface of said accommodation recess. 3. The insulated circuit board with a heat sink according to claim 1, wherein the solder reservoir recess is formed along the entire circumference of the inner side surface of the peripheral wall. an insulating circuit board with a heat sink according to any one of claims 1 to 3;
an electronic component provided on the circuit layer of the insulated circuit board;
and a resin material molded on the electronic component and in the housing recess.

Images