阅读说明：本技术 接合体、带散热器的绝缘电路基板及散热器 (Joined body, insulated circuit board with heat sink, and heat sink ) 是由 寺崎伸幸 于 2019-11-27 设计创作，主要内容包括：本发明提供一种接合体,该接合体通过固相扩散接合由铝合金构成的铝合金部件与由铜或铜合金构成的铜部件而成,冷热循环可靠性优异,且散热特性及强度优异。一种接合体,通过接合铜部件(13B)与铝合金部件(31)而成,其中,铝合金部件(31)的Si浓度在1.5质量％以上且12.5质量％以下的范围内,Fe浓度为0.15质量％以下,Cu浓度为0.05质量％以下,铝合金部件(31)与铜部件(13B)固相扩散接合,位于铝合金部件(31)侧并且由θ相构成的第一金属间化合物层(41)的厚度t1与位于铜部件(13B)侧并且由θ相以外的非θ相构成的第二金属间化合物层(42)的厚度t2的比t2/t1在1.2以上且2.0以下的范围内。(The invention provides a joined body, which is formed by solid phase diffusion bonding of an aluminum alloy component composed of an aluminum alloy and a copper component composed of copper or a copper alloy, and has excellent cold and hot circulation reliability, heat dissipation characteristics and strength. A joined body is formed by joining a copper member (13B) and an aluminum alloy member (31), wherein the aluminum alloy member (31) has an Si concentration in the range of 1.5 to 12.5 mass%, an Fe concentration of 0.15 mass%, and a Cu concentration of 0.05 mass%, the aluminum alloy member (31) and the copper member (13B) are joined by solid phase diffusion, and the ratio t2/t1 of the thickness t1 of a first intermetallic compound layer (41) located on the aluminum alloy member (31) side and composed of a theta phase to the thickness t2 of a second intermetallic compound layer (42) located on the copper member (13B) side and composed of a non-theta phase other than the theta phase is in the range of 1.2 to 2.0.)

1. A joined body obtained by joining a copper member composed of copper or a copper alloy and an aluminum alloy member composed of an aluminum alloy containing Si,

in the aluminum alloy, the Si concentration is within the range of 1.5-12.5 mass%, the Fe concentration is below 0.15 mass%, the Cu concentration is below 0.05 mass%,

the aluminum alloy member is solid-phase diffusion bonded to the copper member,

an intermetallic compound layer formed of an intermetallic compound containing Cu and Al is provided at a bonding interface between the aluminum alloy member and the copper member,

in the intermetallic compound layer, a first intermetallic compound layer and a second intermetallic compound layer are stacked, the first intermetallic compound layer being located on the aluminum alloy member side and being composed of a theta phase, the second intermetallic compound layer being located on the copper member side and being composed of a non-theta phase other than the theta phase,

the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer composed of the theta phase to the thickness t2 of the second intermetallic compound layer composed of the non-theta phase is in the range of 1.2 to 2.0.

2. An insulated circuit board with a heat sink, comprising: an insulating layer; a circuit layer formed on one surface of the insulating layer; a metal layer formed on the other surface of the insulating layer; and a heat sink disposed on a surface of the metal layer opposite to the insulating layer, wherein the insulating circuit board with the heat sink is characterized in that,

the bonding surface of the metal layer to the heat sink is composed of copper or a copper alloy,

wherein a bonding surface with the metal layer in the heat spreader is formed of an aluminum alloy having an Si concentration of 1.5 to 12.5 mass%, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less,

the heat sink is in solid-phase diffusion bonding with the metal layer,

an intermetallic compound layer made of an intermetallic compound containing Cu and Al is provided at a bonding interface between the heat spreader and the metal layer,

in the intermetallic compound layer, a first intermetallic compound layer and a second intermetallic compound layer are stacked, the first intermetallic compound layer being located on the heat sink side and being composed of a theta phase, the second intermetallic compound layer being located on the metal layer side and being composed of a non-theta phase other than the theta phase,

the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer composed of the theta phase to the thickness t2 of the second intermetallic compound layer composed of the non-theta phase is in the range of 1.2 to 2.0.

3. A heat sink is provided with: a heat sink body; and a copper component layer composed of copper or a copper alloy bonded to the heat sink main body, the heat sink being characterized in that,

the heat sink body is composed of an aluminum alloy having an Si concentration of 1.5 to 12.5 mass%, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less,

the heat sink body is solid phase diffusion bonded to the copper component layer,

an intermetallic compound layer formed of an intermetallic compound containing Cu and Al is provided at a bonding interface between the heat sink body and the copper member layer,

in the intermetallic compound layer, a first intermetallic compound layer and a second intermetallic compound layer are stacked, the first intermetallic compound layer being located on the radiator main body side and being composed of a theta phase, the second intermetallic compound layer being located on the copper member layer side and being composed of a non-theta phase other than the theta phase,

the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer composed of the theta phase to the thickness t2 of the second intermetallic compound layer composed of the non-theta phase is in the range of 1.2 to 2.0.

Technical Field

The present invention relates to a joined body formed by joining an aluminum alloy member made of an aluminum alloy and a copper member made of copper or a copper alloy, an insulating circuit board with a heat sink in which a heat sink is joined to an insulating circuit board in which a circuit layer is formed on one surface of an insulating layer, and a heat sink in which a copper member layer is formed on a heat sink main body.

The present application claims priority based on patent application No. 2018-222347, filed in japanese application on 11/28/2018, and the content is incorporated herein by reference.

Background

Semiconductor devices such as LEDs and power modules have a structure in which a semiconductor element is bonded to a circuit layer made of a conductive material.

In a power semiconductor device for high power control used for controlling wind power generation, electric vehicles, hybrid vehicles, and the like, an insulating circuit board having, for example, aluminum nitride (AlN) or aluminum oxide (Al) has been widely used as a substrate on which the power semiconductor device is mounted, because of a large amount of heat generation₂O₃) And a circuit layer formed by bonding a metal plate having excellent conductivity to one surface of the ceramic substrate. Further, as a power module substrate, there is also provided a power module substrate in which a metal layer is formed on the other surface of a ceramic substrate.

For example, a power module disclosed in patent document 1 includes an insulating circuit board having a circuit layer made of aluminum or an aluminum alloy and a metal layer formed on one surface and the other surface of a ceramic substrate, and a semiconductor element bonded to the circuit layer with a solder material.

In addition, the power module has a structure in which a heat sink is joined to the metal layer side of the insulating circuit board, and the heat transmitted from the semiconductor element to the insulating circuit board is dissipated to the outside through the heat sink.

However, when the circuit layer and the metal layer are made of aluminum or an aluminum alloy as in the power module described in patent document 1, an oxide film of Al is formed on the surface thereof, and thus there is a problem that the semiconductor element and the heat sink cannot be bonded by a solder material.

Therefore, patent document 2 proposes an insulated circuit board having a laminated structure in which a circuit layer and a metal layer are an Al layer and a Cu layer. In this insulated circuit board, since the Cu layer is disposed on the surfaces of the circuit layer and the metal layer, the semiconductor element and the heat sink can be bonded well using a solder material. Therefore, the thermal resistance in the stacking direction is reduced, and the heat generated from the semiconductor element can be efficiently transferred to the heat sink side.

As shown in patent document 2, a structure has also been proposed in which a heat sink is used as a heat radiation plate, and the heat radiation plate is screwed to a cooling unit by fastening screws.

Further, patent document 3 proposes an insulated circuit board with a heat sink, in which one of a metal layer and a heat sink is made of aluminum or an aluminum alloy and the other is made of copper or a copper alloy, and the metal layer and the heat sink are solid-phase diffusion bonded. In the insulated circuit board with a heat sink, since the metal layer is solid-phase diffusion bonded to the heat sink, the heat resistance is small and the heat dissipation characteristic is excellent.

Patent document 4 proposes an insulated circuit board with a heat sink in which a heat sink made of an aluminum alloy containing a large amount of Si such as ADC12 and a metal layer made of copper are bonded by solid-phase diffusion. Further, a heat sink in which a heat sink main body made of an aluminum alloy containing a large amount of Si such as ADC12 and a metal component layer made of copper are bonded by solid-phase diffusion has been proposed.

Aluminum alloys such as ADC12, which contain a large amount of Si, can be formed into various shapes because of their high strength and low melting point, and can constitute heat sinks having excellent heat dissipation characteristics.

Patent document 1: japanese patent No. 3171234

Patent document 2: japanese patent laid-open No. 2014-160799

Patent document 3: japanese patent laid-open publication No. 2014-099596

Patent document 4: japanese patent laid-open publication No. 2016-208010

However, aluminum alloys such as ADC12 tend to have low thermal conductivity because of a large amount of additive elements. Therefore, when a semiconductor element or the like generating a large amount of heat is mounted, the heat dissipation characteristics may be insufficient.

On the other hand, pure aluminum has high thermal conductivity and excellent heat dissipation characteristics. However, pure aluminum softens significantly at high temperature, and thus it is difficult to perform screw fastening. Further, since the coefficient of linear thermal expansion is relatively large, the warpage becomes large, and the bonding with another member may be insufficient.

As described in patent documents 3 and 4, when an aluminum alloy member made of an aluminum alloy and a copper member made of copper or a copper alloy are solid-phase diffusion bonded, an intermetallic compound layer made of copper and aluminum is formed at the bonding interface between the aluminum alloy member and the copper member. Here, as shown in fig. 1, the intermetallic compound composed of copper and aluminum has a plurality of phases. Therefore, the intermetallic compound layer formed at the joint interface between the aluminum alloy member and the copper member forms θ phase and η phase₂Phase, ζ₂Phase, delta phase, gamma₂Phases such as facies.

Here, since the intermetallic compound layer is relatively hard and brittle, the intermetallic compound layer may be broken during a load cooling and heating cycle, and the bonding ratio may be lowered.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a joined body in which an aluminum alloy member made of an aluminum alloy and a copper member made of copper or a copper alloy are joined by solid-phase diffusion, and which has excellent cooling-heating cycle reliability, and excellent heat dissipation characteristics and strength, and a heat sink and an insulated circuit board with a heat sink provided with the joined body.

In order to solve the above-described problems, a joined body of the present invention is a joined body obtained by joining a copper member made of copper or a copper alloy and an aluminum alloy member made of an aluminum alloy containing Si, wherein the aluminum alloy has an Si concentration in a range of 1.5 mass% or more and 12.5 mass% or less, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less, the aluminum alloy member and the copper member are solid-phase diffusion joined, an intermetallic compound layer made of an intermetallic compound including Cu and Al is provided at a joining interface between the aluminum alloy member and the copper member, a first intermetallic compound layer and a second intermetallic compound layer are stacked in the intermetallic compound layer, the first intermetallic compound layer is located on the aluminum alloy member side and is made of a θ phase, the second intermetallic compound layer is located on the copper member side and is made of a non- θ phase other than the θ phase, the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer composed of the theta phase to the thickness t2 of the second intermetallic compound layer composed of the non-theta phase is in the range of 1.2 to 2.0.

According to the joined body having such a structure, since the aluminum alloy has an Si concentration in a range of 1.5 mass% or more and 12.5 mass% or less, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less, the aluminum alloy member has high strength and relatively high thermal conductivity. Therefore, the heat diffused in the copper member can be efficiently transferred to the aluminum alloy member side.

Further, in the present invention, since the aluminum alloy constituting the aluminum alloy member has an Si concentration in a range of 1.5 mass% or more and 12.5 mass% or less, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less, and a ratio t2/t1 of a thickness t1 of a first intermetallic compound layer located on the aluminum alloy member side and composed of a θ phase to a thickness t2 of a second intermetallic compound layer located on the copper member side and composed of a non- θ phase other than the θ phase in an intermetallic compound layer formed at a joint interface between the aluminum alloy member and the copper member is 1.2 or more, the thickness of the first intermetallic compound layer composed of the θ phase does not have to be excessively thick, and occurrence of cracking due to the θ phase can be suppressed. Further, by securing the thickness of the second intermetallic compound layer made of a non- θ phase on the copper member side, the deformation resistance of the copper member is large, and even when an external force is applied by fastening or the like, the copper member is not easily deformed, and the occurrence of cracking in the intermetallic compound layer can be suppressed.

Further, since the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer to the thickness t2 of the second intermetallic compound layer is 2.0 or less, the thickness of the first intermetallic compound layer composed of the θ phase on the aluminum alloy member side is ensured, the deformation resistance of the aluminum alloy member is large, and even when an external force is applied by fastening or the like, the aluminum alloy member is not easily deformed, and the occurrence of cracking of the intermetallic compound layer can be suppressed.

The insulated circuit board with a heat sink of the present invention is an insulated circuit board with a heat sink comprising an insulating layer, a circuit layer formed on one surface of the insulating layer, a metal layer formed on the other surface of the insulating layer, and a heat sink disposed on a surface of the metal layer opposite to the insulating layer, wherein a bonding surface of the metal layer to the heat sink is made of copper or a copper alloy, the bonding surface of the heat sink to the metal layer is made of an aluminum alloy having an Si concentration of 1.5 mass% or more and 12.5 mass% or less, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less, the heat sink is solid-phase diffusion bonded to the metal layer, an intermetallic compound layer made of an intermetallic compound including an intermetallic compound of Cu and Al is provided at a bonding interface between the heat sink and the metal layer, and the intermetallic compound layer, a first intermetallic compound layer and a second intermetallic compound layer are stacked, the first intermetallic compound layer being located on the heat sink side and being composed of a theta phase, the second intermetallic compound layer being located on the metal layer side and being composed of a non-theta phase other than the theta phase, a ratio t2/t1 of a thickness t1 of the first intermetallic compound layer composed of the theta phase to a thickness t2 of the second intermetallic compound layer composed of the non-theta phase being in a range of 1.2 to 2.0.

According to the insulated circuit board with a heat sink having this configuration, since the heat sink is made of an aluminum alloy having an Si concentration in a range of 1.5 mass% or more and 12.5 mass% or less, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less, the heat sink has high strength, can be screwed, can suppress the occurrence of warpage, and can be brought into close contact with a cooler or the like. Further, since the heat sink has a high thermal conductivity, the heat sink has excellent heat dissipation characteristics.

In the intermetallic compound layer formed at the junction interface between the heat spreader and the metal layer, the ratio t2/t1 between the thickness t1 of the first intermetallic compound layer located on the heat spreader side and composed of the θ phase and the thickness t2 of the second intermetallic compound layer located on the metal layer side and composed of a non- θ phase other than the θ phase is 1.2 or more, and therefore the thickness of the first intermetallic compound layer composed of the θ phase does not need to be excessively thick, and the occurrence of cracking due to the θ phase can be suppressed. Further, by securing the thickness of the second intermetallic compound layer made of a non- θ phase on the side of the metal layer, the deformation resistance of the metal layer is large, and even when an external force is applied by fastening or the like, the metal layer is not easily deformed, and the occurrence of cracking in the intermetallic compound layer can be suppressed.

Further, since the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer to the thickness t2 of the second intermetallic compound layer is 2.0 or less, the thickness of the first intermetallic compound layer made of the θ phase on the radiator side is ensured, the deformation resistance of the radiator is large, and the radiator is not easily deformed even when an external force is applied by fastening or the like, and the occurrence of cracking of the intermetallic compound layer can be suppressed.

The heat sink of the present invention is a heat sink including a heat sink main body and a copper component layer made of copper or a copper alloy bonded to the heat sink main body, the heat sink main body being made of an aluminum alloy having an Si concentration in a range of 1.5 mass% or more and 12.5 mass% or less, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less, the heat sink main body being solid-phase diffusion bonded to the copper component layer, an intermetallic compound layer made of an intermetallic compound including Cu and Al being provided at a bonding interface between the heat sink main body and the copper component layer, a first intermetallic compound layer and a second intermetallic compound layer being stacked in the intermetallic compound layer, the first intermetallic compound layer being located on the heat sink main body side and made of a theta phase, the second intermetallic compound layer being located on the copper component layer side and made of a non-theta phase other than the theta phase, the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer composed of the theta phase to the thickness t2 of the second intermetallic compound layer composed of the non-theta phase is in the range of 1.2 to 2.0.

According to the heat sink of this configuration, since the heat sink main body is made of the aluminum alloy having the Si concentration in the range of 1.5 mass% or more and 12.5 mass% or less, the Fe concentration of 0.15 mass% or less, and the Cu concentration of 0.05 mass% or less, the heat sink main body has high strength, can be screwed, can suppress the occurrence of warpage, and can be brought into close contact with a cooler or the like. Further, since the heat sink body has a high thermal conductivity, the heat sink body has excellent heat dissipation properties.

In the intermetallic compound layer formed at the junction interface between the heat sink body and the copper member layer, the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer located on the heat sink body side and composed of the θ phase to the thickness t2 of the second intermetallic compound layer located on the copper member layer side and composed of a non- θ phase other than the θ phase is 1.2 or more, and therefore the thickness of the first intermetallic compound layer composed of the θ phase does not have to be excessively thick, and the occurrence of cracking due to the θ phase can be suppressed. Further, by securing the thickness of the second intermetallic compound layer made of a non- θ phase on the copper member layer side, the deformation resistance of the copper member layer is large, and even if an external force is applied by fastening or the like, the copper member layer is not easily deformed, and the occurrence of cracking in the intermetallic compound layer can be suppressed.

Further, since the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer to the thickness t2 of the second intermetallic compound layer is 2.0 or less, the thickness of the first intermetallic compound layer made of the θ phase located on the radiator main body side is secured, the deformation resistance of the radiator main body is large, and the radiator main body is not easily deformed even when an external force is applied by fastening or the like, and the occurrence of cracking of the intermetallic compound layer can be suppressed.

According to the present invention, there can be provided a joined body in which an aluminum alloy member made of an aluminum alloy and a copper member made of copper or a copper alloy are joined by solid-phase diffusion, and which is excellent in cooling-heating cycle reliability, heat dissipation characteristics, and strength, and an insulated circuit board with a heat sink and a heat sink provided with the joined body.

Drawings

FIG. 1 is a two-dimensional state diagram of Cu and Al.

Fig. 2 is a schematic explanatory view of a power module including the insulated circuit board with a heat sink according to the first embodiment of the present invention.

Fig. 3 is an enlarged cross-sectional explanatory view of a bonding interface between the heat sink and the metal layer (Cu layer) of the insulated circuit board with a heat sink shown in fig. 2.

Fig. 4 is a flowchart illustrating a method for manufacturing the insulated circuit board with a heat sink according to the first embodiment.

Fig. 5 is a schematic explanatory view of a method for manufacturing the insulated circuit board with a heat sink according to the first embodiment.

Fig. 6 is a schematic explanatory view of a heat sink according to a second embodiment of the present invention.

Fig. 7 is an enlarged cross-sectional explanatory view of a joint interface between the heat sink main body and the copper component layer of the heat sink shown in fig. 6.

Fig. 8 is a flowchart illustrating a method of manufacturing a heat sink according to a second embodiment.

Fig. 9 is a schematic explanatory view of a method for manufacturing a heat sink according to a second embodiment.

Fig. 10 is a schematic explanatory view of a power module including an insulated circuit board with a heat sink according to another embodiment of the present invention.

Fig. 11 is a schematic explanatory view showing a state of solid-phase diffusion bonding by an energization heating method.

Detailed Description

(first embodiment)

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 2 shows a power module 1 using an insulated circuit board with a heat sink 30 according to a first embodiment of the present invention.

The power module 1 includes a heat sink-equipped insulating circuit board 30 and a semiconductor element 3, and the semiconductor element 3 is bonded to one surface (upper surface in fig. 2) of the heat sink-equipped insulating circuit board 30 by a solder layer 2.

The insulated circuit board with a heat sink 30 includes the insulated circuit board 10 and a heat sink 31 bonded to the insulated circuit board 10.

The insulated circuit board 10 includes a ceramic substrate 11 constituting an insulating layer, a circuit layer 12 disposed on one surface (upper surface in fig. 2) of the ceramic substrate 11, and a metal layer 13 disposed on the other surface of the ceramic substrate 11.

The ceramic substrate 11 is made of silicon nitride (Si) having excellent insulating properties and heat dissipation properties₃N₄) Aluminum nitride (AlN) and aluminum oxide (Al)₂O₃) And the like. In the present embodiment, the ceramic substrate 11 is made of aluminum nitride (AlN) having particularly excellent heat dissipation properties. The thickness of the ceramic substrate 11 is set to be, for example, 0.2 to 1.5mm, and in the present embodiment, 0.635 mm.

As shown in fig. 5, the circuit layer 12 is formed by bonding an aluminum plate 22 made of aluminum or an aluminum alloy to one surface of the ceramic substrate 11. In the present embodiment, the circuit layer 12 is formed by joining a rolled sheet (aluminum sheet 22) of aluminum (2N aluminum) having a purity of 99 mass% or more or aluminum (4N aluminum) having a purity of 99.99 mass% or more to the ceramic substrate 11. The thickness of the aluminum plate 22 to be the circuit layer 12 is set to be in the range of 0.1mm to 1.0mm, and in the present embodiment, 0.6 mm.

As shown in fig. 2, the metal layer 13 includes an Al layer 13A disposed on the other surface of the ceramic substrate 11 and a Cu layer 13B laminated on the surface of the Al layer 13A opposite to the surface to which the ceramic substrate 11 is bonded.

As shown in fig. 5, the Al layer 13A is formed by bonding an aluminum plate 23A made of aluminum or an aluminum alloy to the other surface of the ceramic substrate 11. In the present embodiment, the Al layer 13A is formed by joining a rolled sheet (aluminum sheet 23A) of aluminum (2N aluminum) having a purity of 99 mass% or more or aluminum (4N aluminum) having a purity of 99.99 mass% or more to the ceramic substrate 11. The thickness of the aluminum plate 23A to be joined is set to be in the range of 0.1mm to 3.0mm, and in the present embodiment, 0.6 mm.

As shown in fig. 5, the Cu layer 13B is formed by bonding a copper plate 23B made of copper or a copper alloy to the other surface of the Al layer 13A. In the present embodiment, the Cu layer 13B is formed by joining rolled plates (copper plates 23B) of oxygen-free copper. The thickness of the Cu layer 13B is set to be in the range of 0.1mm to 6mm, and in the present embodiment, 1 mm.

The heat sink 31 is for dissipating heat on the side of the insulating circuit board 10, and in the present embodiment, as shown in fig. 2, a circulation path 32 through which a cooling medium flows is provided. The heat spreader 31 is made of an aluminum alloy having an Si concentration in the range of 1.5 mass% to 12.5 mass%, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less. In addition, in the heat spreader 31 (aluminum alloy), Si precipitates are finely dispersed.

Here, the heat spreader 31 is solid-phase diffusion bonded to the metal layer 13(Cu layer 13B).

As shown in fig. 3, an intermetallic compound layer 40 is formed at the bonding interface between the metal layer 13(Cu layer 13B) and the heat spreader 31. The intermetallic compound layer 40 is formed by interdiffusing Al atoms of the heat spreader 31 and Cu atoms of the metal layer 13(Cu layer 13B).

As shown in fig. 3, the intermetallic compound layer 40 is composed of a first intermetallic compound layer 41 and a second intermetallic compound layer 42, the first intermetallic compound layer 41 being disposed on the heat sink 31 side and composed of the θ phase of the intermetallic compound of Cu and Al, and the second intermetallic compound layer 42 being disposed on the metal layer 13 side and composed of η other than the θ phase₂Phase, ζ₂Phase, delta phase, gamma₂Equal non-theta phase composition.

Here, the thickness of the intermetallic compound layer 40 is set in the range of 10 μm to 80 μm, preferably 20 μm to 50 μm.

Then, the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer 41 composed of the θ phase to the thickness t2 of the second intermetallic compound layer 42 composed of the non- θ phase is in the range of 1.2 or more and 2.0 or less.

The lower limit of the thickness ratio t2/t1 is preferably 1.4 or more, and more preferably 1.5 or more. The upper limit of the thickness ratio t2/t1 is preferably 1.8 or less, and more preferably 1.6 or less.

The lower limit of the thickness t1 of the first intermetallic compound layer 41 composed of the θ phase is preferably 5 μm or more, and more preferably 10 μm or more. On the other hand, the upper limit of the thickness t1 of the first intermetallic compound layer 41 composed of the θ phase is preferably 20 μm or less, and more preferably 15 μm or less.

Next, a method for manufacturing the insulated circuit board with a heat sink 30 according to the present embodiment will be described with reference to fig. 4 and 5.

(Circuit layer and Al layer Forming Process S01)

First, as shown in fig. 5, aluminum sheet 22 to be circuit layer 12 is laminated on one surface of ceramic substrate 11 via Al — Si-based brazing filler metal foil 26.

On the other surface of the ceramic substrate 11, an aluminum plate 23A to be an Al layer 13A is laminated via an Al — Si-based brazing filler metal foil 26. In the present embodiment, an Al-8 mass% Si alloy foil with a thickness of 10 μm was used as the Al-Si based brazing filler metal foil 26.

Then, pressing (pressure 1-35 kgf/cm) in the laminating direction²(0.1 to 3.5MPa)) and joining aluminum plate 22 and ceramic substrate 11 to form circuit layer 12. Further, the ceramic substrate 11 and the aluminum plate 23A are joined to form an Al layer 13A.

Here, it is preferable that the pressure in the vacuum heating furnace is set to 10^-6Pa is 10 or more^-3Pa or lower, the heating temperature is set to 600 ℃ to 650 ℃, and the holding time at the heating temperature is set to 15 minutes to 180 minutes.

(Cu layer (Metal layer) Forming Process S02)

Next, on the other surface side of the Al layer 13A, a copper plate 23B to be a Cu layer 13B is laminated.

Then, pressing the laminated substrate in the laminating direction (pressure of 3 to 35 kgf/cm)²(0.3 to 3.5MPa)) and the Al layer 13A and the copper plate 23B are solid-phase diffusion bonded to each other by heating the aluminum alloy sheet in a vacuum heating furnace to form the metal layer 13.

Here, it is preferable that the pressure in the vacuum heating furnace is set to 10^-6Pa is 10 or more^-3Pa or lower, the heating temperature is set to 400 ℃ to 548 ℃, and the holding time at the heating temperature is set to 5 minutes to 240 minutes.

In addition, the respective bonding surfaces of the Al layer 13A and the copper plate 23B to be solid-phase diffusion bonded are previously scratched to be smooth.

In this manner, the insulating circuit substrate 10 is manufactured.

(Heat sink preparation step S11)

On the other hand, a heat sink 31 is prepared. First, an aluminum alloy sheet to be a raw material of the heat sink 31 is manufactured. Specifically, an aluminum alloy melt is melted, the composition of which is adjusted so that the Si concentration is in the range of 1.5 mass% to 12.5 mass%, the Fe concentration is 0.15 mass% or less, and the Cu concentration is 0.05 mass% or less. Then, an aluminum alloy sheet is produced by a twin roll method using the aluminum alloy melt. In the twin roll method, since the cooling rate is high, Si precipitates are finely dispersed.

Then, the aluminum alloy sheet is processed to form the heat sink 31.

(Metal layer and Heat sink bonding step S03)

Next, the metal layer 13(Cu layer 13B) of the insulated circuit board 10 and the heat sink 31 are laminated, and pressure is applied in the laminating direction (pressure is 5 to 35 kgf/cm)²(0.5 to 3.5MPa)) and is placed in a vacuum heating furnace and heated, thereby solid-phase diffusion bonding the metal layer 13(Cu layer 13B) and the heat sink 31. In addition, the bonding surfaces of the metal layer 13(Cu layer 13B) and the heat spreader 31 to be solid-phase diffusion bonded are removed in advanceThe face is scratched to achieve smoothness.

Here, it is preferable that the pressure in the vacuum heating furnace is set to 10^-6Pa is 10 or more^-3Pa or less, the heating temperature is set to 400 ℃ to 520 ℃ inclusive, and the holding time at the heating temperature is set to 15 minutes to 300 minutes inclusive.

In the metal layer and heat sink bonding step S03, Cu atoms in the Cu layer 13B and Al atoms in the heat sink 31 diffuse into each other, and as shown in fig. 3, an intermetallic compound layer 40 is formed by stacking a first intermetallic compound layer 41 composed of a θ phase and a second intermetallic compound layer 42 composed of a non- θ phase.

In this manner, the insulated circuit board with a heat sink 30 of the present embodiment is manufactured.

Here, in the present embodiment, since the heat spreader 31 is formed using the aluminum alloy sheet manufactured by the twin roll method as described above, Si precipitates are finely dispersed in the heat spreader 31. Since Si diffuses at a higher rate than Al, diffusion of Cu is promoted by the dispersion of Si precipitates, and the θ phase grows largely. Thus, the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer 41 composed of the θ phase to the thickness t2 of the second intermetallic compound layer 42 composed of the non- θ phase is in the range of 1.2 to 2.0. Further, since coarse Si precipitates are not present in the heat spreader 31, excessive formation of kirkendall cavities can be suppressed.

(semiconductor element bonding step S04)

Next, the semiconductor element 3 is laminated on one surface (front surface) of the circuit layer 12 with a solder material, and solder bonding is performed in a reducing furnace.

In this manner, the power module 1 of the present embodiment is manufactured.

According to the insulated circuit board with a heat sink 30 of the present embodiment configured as described above, since the heat sink 31 is made of an aluminum alloy having an Si concentration in a range of 1.5 mass% or more and 12.5 mass% or less, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less, the heat sink 31 has high strength, can be screwed, and can suppress the occurrence of warpage. Further, the heat sink 31 has high thermal conductivity, and thus has excellent heat dissipation properties.

In the present embodiment, in the intermetallic compound layer 40 formed at the bonding interface between the heat spreader 31 and the metal layer 13, the ratio t2/t1 between the thickness t1 of the first intermetallic compound layer 41 located on the heat spreader 31 side and composed of the θ phase and the thickness t2 of the second intermetallic compound layer 42 located on the metal layer 13 side and composed of a non- θ phase other than the θ phase is 1.2 or more. Thus, the thickness of the first intermetallic compound layer 41 formed of the θ phase does not need to be excessively thick, and the occurrence of cracking due to the first intermetallic compound layer 41 can be suppressed. Further, by securing the thickness of the second intermetallic compound layer 42 made of a non- θ phase on the metal layer 13 side, the deformation resistance of the metal layer 13 is large, and even if an external force is applied, the metal layer 13 is not easily deformed, and the occurrence of cracking of the intermetallic compound layer 40 can be suppressed.

Further, since the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer 41 to the thickness t2 of the second intermetallic compound layer 42 is 2.0 or less, the thickness of the first intermetallic compound layer 41 composed of the θ phase located on the heat sink 31 side is secured, and the deformation resistance of the heat sink 31 is large, and even when an external force is applied, the heat sink 31 is not easily deformed, and the occurrence of cracking of the intermetallic compound layer 40 can be suppressed.

(second embodiment)

Next, a heat sink according to a second embodiment of the present invention will be described. Fig. 6 shows a heat sink 101 according to a second embodiment of the present invention.

The heat sink 101 includes a heat sink body 110 and a copper member layer 117 made of copper or a copper alloy laminated on one surface (upper side in fig. 6) of the heat sink body 110. In the present embodiment, as shown in fig. 9, the copper member layer 117 is formed by joining a copper plate 127 formed of a rolled sheet of oxygen-free copper.

The radiator main body 110 is provided with a flow path 111 through which a cooling medium flows. The heat sink body 110 is made of an aluminum alloy having an Si concentration in the range of 1.5 mass% to 12.5 mass%, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less. In addition, Si precipitates are finely dispersed in the heat sink body 110 (aluminum alloy).

Here, the heat sink body 110 and the copper member layer 117 are solid-phase diffusion bonded.

As shown in fig. 7, an intermetallic compound layer 140 containing Al and Cu is formed at the bonding interface between the heat sink body 110 and the copper member layer 117. The intermetallic compound layer 140 is formed by interdiffusion of Al atoms of the heat sink main body 110 and Cu atoms of the copper member layer 117.

As shown in fig. 7, the intermetallic compound layer 140 includes a first intermetallic compound layer 141 made of a θ phase of an intermetallic compound of Cu and Al disposed on the heat sink body 110 side, and η other than the θ phase disposed on the copper member layer 117 side₂Phase, ζ₂Phase, delta phase, gamma₂And a second intermetallic compound layer 142 composed of equal non-theta phases.

Here, the thickness of the intermetallic compound layer 140 is set in the range of 10 μm to 80 μm, preferably 20 μm to 50 μm.

Further, the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer 141 composed of the θ phase to the thickness t2 of the second intermetallic compound layer 142 composed of the non- θ phase is in the range of 1.2 to 2.0.

The lower limit of the thickness ratio t2/t1 is preferably 1.4 or more, and more preferably 1.5 or more. The upper limit of the thickness ratio t2/t1 is preferably 1.8 or less, and more preferably 1.6 or less.

The lower limit of the thickness t1 of the first intermetallic compound layer 141 composed of the θ phase is preferably 5 μm or more, and more preferably 10 μm or more. On the other hand, the upper limit of the thickness t1 of the first intermetallic compound layer 141 composed of the θ phase is preferably 20 μm or less, and more preferably 15 μm or less.

Next, a method for manufacturing the heat sink 101 according to the present embodiment will be described with reference to fig. 8 and 9.

(radiator main body preparation step S101)

The bonded heat sink body 110 is prepared. First, an aluminum alloy plate to be a raw material of the heat sink main body 110 is manufactured. Specifically, an aluminum alloy melt is melted, the composition of which is adjusted so that the Si concentration is in the range of 1.5 mass% to 12.5 mass%, the Fe concentration is 0.15 mass% or less, and the Cu concentration is 0.05 mass% or less. Then, an aluminum alloy sheet is produced by a twin roll method using the aluminum alloy melt.

In the twin roll method, since the cooling rate is high, Si precipitates are finely dispersed.

Then, the aluminum alloy plate is processed to mold the heat sink body 110.

(Heat sink body and copper component layer joining step S102)

Next, as shown in FIG. 9, the heat sink body 110 and the copper plate 127 to be the copper member layer 117 are laminated, and pressure (pressure 5 to 35 kgf/cm) is applied in the laminating direction²(0.5 to 3.5MPa)) in a vacuum furnace, and the copper plate 127 and the heat sink main body 110 are solid-phase diffusion bonded by heating. In addition, the respective bonding surfaces of the copper plate 127 and the heat sink main body 110 to which the solid-phase diffusion bonding is applied are previously scratched to be smooth.

Here, it is preferable that the pressure in the vacuum heating furnace is set to 10^-6Pa is 10 or more^-3Pa or less, a heating temperature of 450 to 520 ℃ inclusive, and a holding time at the heating temperature of 15 to 300 minutes inclusive.

In the heat sink main body and copper member layer bonding step S102, Cu atoms in the copper member layer 117 (copper plate 127) and Al atoms in the heat sink main body 110 are diffused into each other, and as shown in fig. 7, an intermetallic compound layer 140 in which a first intermetallic compound layer 141 composed of a θ phase and a second intermetallic compound layer 142 composed of a non- θ phase are stacked is formed.

In this manner, the heat sink 101 of the present embodiment is manufactured.

Here, in the present embodiment, since the heat sink main body 110 is molded using the aluminum alloy plate manufactured by the twin roll method as described above, Si precipitates are finely dispersed in the heat sink main body 110. Since Si diffuses at a higher rate than Al, diffusion of Cu is promoted by the dispersion of Si precipitates, and the θ phase grows largely. Thus, the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer 141 composed of the θ phase to the thickness t2 of the second intermetallic compound layer 142 composed of the non- θ phase is in the range of 1.2 to 2.0. In addition, since coarse Si precipitates are not present in the heat sink main body 110, excessive formation of kirkendall cavities can be suppressed.

According to the heat sink 101 of the present embodiment configured as described above, since the copper member layer 117 is formed by joining the copper plate 127 made of a rolled plate of oxygen-free copper to one surface side of the heat sink main body 110, heat can be diffused in the planar direction by the copper member layer 117, and the heat radiation characteristics can be greatly improved. Further, other components can be bonded to the heat sink 101 with solder or the like.

In the present embodiment, the heat sink body 110 is made of an aluminum alloy having an Si concentration in the range of 1.5 mass% to 12.5 mass%, an Fe concentration of 0.15 mass% or less, and a Cu concentration of 0.05 mass% or less, and therefore the heat sink body 110 has high strength, can be screwed, can suppress the occurrence of warpage, and can be brought into close contact with a cooler or the like. Further, since the heat sink body 110 has high thermal conductivity, the heat dissipation property is excellent.

Further, in the intermetallic compound layer 140 formed at the joining interface between the heat sink main body 110 and the copper component layer 117, the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer 141 located on the heat sink main body 110 side and composed of the θ phase to the thickness t2 of the second intermetallic compound layer 142 located on the copper component layer 117 side and composed of a non- θ phase other than the θ phase is 1.2 or more, and therefore the thickness of the first intermetallic compound layer 141 composed of the θ phase does not have to be excessively thick, and the occurrence of cracking due to the first intermetallic compound layer 141 can be suppressed. Further, by securing the thickness of the second intermetallic compound layer 142 made of a non- θ phase on the copper member layer 117 side, the deformation resistance of the copper member layer 117 is large, and even when an external force is applied by fastening or the like, the copper member layer 117 is not easily deformed, and the occurrence of cracking of the intermetallic compound layer 140 can be suppressed.

Further, since the ratio t2/t1 of the thickness t1 of the first intermetallic compound layer 141 to the thickness t2 of the second intermetallic compound layer 142 is 2.0 or less, the thickness of the first intermetallic compound layer 141 made of the θ phase located on the heat sink main body 110 side is secured, and the deformation resistance of the heat sink main body 110 is large, and even when an external force is applied by fastening or the like, the heat sink main body 110 is not easily deformed, and the occurrence of cracking of the intermetallic compound layer 140 can be suppressed.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can be modified as appropriate without departing from the scope of the technical idea of the present invention.

For example, in the first embodiment, the metal layer 13 is described as a layer having the Al layer 13A and the Cu layer 13B, but the present invention is not limited thereto, and the entire metal layer may be made of copper or a copper alloy as shown in fig. 10. In the insulated circuit board with a heat sink 230 shown in fig. 10, a copper plate is bonded to the other surface (lower side in fig. 10) of the ceramic substrate 11 by a DBC method or an active metal brazing method, and a metal layer 213 made of copper or a copper alloy is formed. Then, the metal layer 213 is solid-phase diffusion bonded to the heat spreader 31. In the insulating circuit board 210 shown in fig. 10, the circuit layer 212 is also made of copper or a copper alloy.

In the first embodiment, the circuit layer is described as a layer formed by bonding aluminum plates having a purity of 99 mass%, but the circuit layer is not limited to this, and may be formed of pure aluminum having a purity of 99.99 mass% or more, another aluminum or aluminum alloy, or another metal such as copper or copper alloy. The circuit layer may have a two-layer structure of an Al layer and a Cu layer. This is also true of the insulating circuit board 210 shown in fig. 10.

In the metal layer and heat sink bonding step S03 of the first embodiment, the metal layer 13(Cu layer 13B) and the heat sink 31 are stacked and placed in a vacuum heating furnace under pressure in the stacking direction to be heated. In the step S102 of bonding the heat sink body and the copper member layer according to the second embodiment, the copper member layer is bonded to the copper member layerLaminating the heat sink main body 110 and the copper plate 127 to be the copper member layer 117, and pressing the laminated heat sink main body and the copper plate in a laminating direction (pressure of 5 to 35 kgf/cm)²(0.5 to 3.5MPa)) in a vacuum heating furnace, and heating the resultant. However, the present invention is not limited to the first embodiment or the second embodiment, and as shown in fig. 11, an energization heating method may be applied to the solid-phase diffusion bonding of aluminum alloy member 301 (heat sink 31, heat sink body 110) and copper member 302 (metal layer 13, copper member layer 117).

When the energization heating is performed, as shown in fig. 11, the aluminum alloy member 301 and the copper member 302 are stacked, and the stacked body is pressed in the stacking direction by the pair of electrodes 312 and 312 through the carbon plates 311 and 311, and the aluminum alloy member 301 and the copper member 302 are energized. Then, the carbon plates 311 and the aluminum alloy member 301 and the copper member 302 are heated by joule heat, and the aluminum alloy member 301 and the copper member 302 are solid-phase diffusion bonded.

In the above-described energization heating method, since the aluminum alloy member 301 and the copper member 302 are directly energized and heated, the temperature rise can be relatively fast and, for example, 30 to 100 ℃/min, and solid-phase diffusion bonding can be performed in a short time. This makes it possible to bond the bonding surfaces with less influence of oxidation, for example, even in an atmospheric atmosphere. Further, depending on the resistance values and specific heats of the aluminum alloy member 301 and the copper member 302, the aluminum alloy member 301 and the copper member 302 can be joined even in a state where a temperature difference is generated between them, and the difference in thermal expansion can be reduced and the thermal stress can be reduced.

In the above-mentioned energization heating method, the pressurizing load generated by the pair of electrodes 312 and 312 is preferably 30kgf/cm²Above and 100kgf/cm²In the following range (3MPa to 10 MPa).

When the energization heating method is applied, the surface roughness of the aluminum alloy member 301 and the copper member 302 is preferably in the range of 0.3 μm or more and 0.6 μm or less in terms of arithmetic average roughness Ra (JIS B0601: 2001), or in the range of 1.3 μm or more and 2.3 μm or less in terms of maximum height Rz (JIS B0601: 2001). In the case of the electric current heating method, if the surface roughness of the bonding surface is too small, the interface contact resistance decreases, and it is difficult to locally heat the bonding interface, so that it is preferable that the surface roughness of the bonding surface is within the above range.

In addition, the above-described energization heating method may be used in the metal layer and heat sink bonding step S03 of the first embodiment, but in this case, since the ceramic substrate 11 is an insulator, it is necessary to short-circuit the carbon plates 311, 311 with a jig made of carbon, for example. The bonding conditions were the same as those for the above-described aluminum alloy member 301 and copper member 302.

The surface roughness of the metal layer 13(Cu layer 13B) and the heat sink 31 is the same as that of the aluminum alloy member 301 and the copper member 302 described above.

Examples

The results of the confirmation experiment performed to confirm the effects of the present invention will be described below.

(preparation of test piece)

On one surface of the aluminum alloy sheet (50mm × 50mm, thickness 5mm) shown in table 1, a copper sheet (40mm × 40mm, thickness 5mm) made of oxygen-free copper was solid-phase diffusion bonded by the method described in the above embodiment. In addition, in the present example, the aluminum alloy sheet was manufactured by a twin roll method. In the comparative example, an aluminum alloy sheet was produced by producing an ingot in a block shape, and hot rolling and cold rolling the ingot.

Then, in the present invention examples and comparative examples, the aluminum alloy sheet and the copper sheet were laminated in the lamination direction at 15kgf/cm²The solid-phase diffusion bonding was performed at 500 ℃ for the holding time shown in Table 1 by a vacuum heating furnace by pressing with a load of (1.5 MPa).

(hardness of aluminum alloy plate)

Indentation hardness was measured by nano indentation method (measuring apparatus: ENT-1100a (ELIONIX INC.)) for the aluminum alloy sheet of the joined body. The measurement was performed at 10 points in the central portion in the thickness direction of the aluminum alloy plate, and the average value was obtained. In addition, as for the indentation hardness, a triangular pyramid diamond indenter called a kirchki indenter having a water chestnut angle of 114.8 ° or more and 115.1 ° or less was used, and the test load was measured as5000mgf, load-displacement correlation when load is applied, and indentation hardness of 37.926 × 10^-3X (load [ mgf)]Division by displacement [ mu m]²) The equation (c) is obtained.

(evaluation of intermetallic Compound layer)

In the cross-sectional view of the joined body of the aluminum alloy plate and the copper plate subjected to the solid-phase diffusion bonding, the thickness t1 of the θ phase and the thickness t2 of the non- θ phase were measured in the intermetallic compound layer formed at the bonding interface.

A linear analysis was performed in the thickness direction of the position including the intermetallic compound layer using EPMA (JXA-8530F: JEOL Ltd.). The total amount of Cu and Al is 100 atomic%, the region with Cu concentration of 30-35 atomic% is theta phase, and the region with Cu concentration of 46-72 atomic% is non-theta phase. In addition, a site having a local peak due to Si precipitates was excluded.

Then, the above observation was performed in five fields, and the average value of the θ -phase thickness t1 and the average value of the non- θ -phase thickness t2 were calculated. The measurement results are shown in table 1.

(Cold and Heat cycle test)

Next, a cooling-heating cycle test was performed on the joined body thus produced. The test piece (power module with heat sink) was subjected to 2500 cycles of cooling and heating at-50 ℃ for 45 minutes and 175 ℃ for 45 minutes in an air bath using an ESPEC CORP, manufactured by TSA-72 ES.

Then, the thermal resistance and the bonding rate of the bonded body before the cold-heat cycle test in the stacking direction and the thermal resistance and the bonding rate of the bonded body after the cold-heat cycle test in the stacking direction were evaluated as follows.

(evaluation of bonding Rate)

The joint ratio of the joint portion between the aluminum alloy plate and the metal plate of the joined body was evaluated using an ultrasonic flaw detector (FineSAT 200: Hitachi Power Solutions co., Ltd.), and was calculated according to the following equation. Here, the initial joining area is an area to be joined before joining, that is, an area of the aluminum alloy sheet. In the ultrasonic flaw detection image, since the peeling is indicated by a white portion, the area of the white portion is defined as the peeled area. The evaluation results are shown in table 1.

Bonding ratio (%) { (initial bonding area) - (peeling area) }/(initial bonding area) × 100

(measurement of thermal resistance)

A heating piece (13 mm. times.10 mm. times.0.25 mm) was welded to the surface of the metal plate, and the aluminum alloy plate was joined to the cooler by brazing. Next, the heating chip was heated at a power of 100W, and the temperature of the heating chip was actually measured using a thermocouple (K thermocouple, level 1). Then, the temperature of the cooling medium (ethylene glycol: water: 9:1) flowing through the cooler was actually measured. Then, the value obtained by dividing the power by the temperature difference between the heating fin and the cooling medium is set as the thermal resistance.

The thermal resistance before the cold-heat cycle test of comparative example 1 was set to 1, and the thermal resistance was evaluated by a ratio to that of comparative example 1. The evaluation results are shown in table 1.

[ Table 1]

In comparative example 1, the Si concentration of the aluminum alloy sheet was 0.2 mass%, which is less than the range of the present invention, and the ratio t2/t1 of the theta phase thickness t1 to the non-theta phase thickness t2 was 2.8, which is more than the range of the present invention, the joint ratio decreased after the cooling-heating cycle load, and the thermal resistance increased greatly.

In comparative example 2, the Si concentration of the aluminum alloy sheet was 18.5 mass%, which is larger than the range of the present invention, and the ratio t2/t1 of the theta phase thickness t1 to the non-theta phase thickness t2 was 1.0, which is smaller than the range of the present invention, the joint ratio decreased after the cooling-heating cycle load, and the thermal resistance increased greatly.

In comparative example 3, the Fe concentration of the aluminum alloy sheet was 0.42 mass% which is larger than the range of the present invention, and the bonding ratio was decreased and the thermal resistance was greatly increased after the cooling-heating cycle load.

In comparative example 4, the Cu concentration of the aluminum alloy sheet was 0.26 mass%, which is larger than the range of the present invention, and the bonding ratio was greatly decreased and the thermal resistance was greatly increased after the cooling-heating cycle load.

On the other hand, in inventive examples 1 to 8 in which the Si concentration, Fe concentration, Cu concentration, and the ratio t2/t1 of the θ phase thickness t1 to the non- θ phase thickness t2 of the aluminum alloy sheet were within the range of the present invention, respectively, the thermal resistance was lower than that of comparative example 1. Also, after the cooling-heating cycle load, the bonding rate does not decrease significantly, and the thermal resistance does not increase significantly.

As described above, according to examples 1 to 8 of the present invention, it was confirmed that a joined body in which an aluminum alloy member made of an aluminum alloy and a copper member made of copper or a copper alloy are joined by solid-phase diffusion, and which is excellent in cooling-heating cycle reliability and heat dissipation characteristics and strength, can be provided.

Industrial applicability

The joined body of the present invention, and the insulated circuit board with a heat sink and the heat sink provided with the joined body can be suitably used for devices (for example, wind power generation devices, electric vehicles, hybrid vehicles, and the like) having a control circuit provided with a power semiconductor element for high-power control having a large amount of heat generation.

Description of the symbols

10. 210 insulating circuit board

11 ceramic substrate

13. 213 Metal layer

13B Cu layer (copper parts)

31 Heat radiating plate (aluminium alloy parts)

40 intermetallic compound layer

41 first intermetallic compound

42 second intermetallic compound

101 radiator

110 heating panel main body (aluminium alloy parts)

117 copper component layer

140 intermetallic compound layer

141 first intermetallic compound

142 second intermetallic compound