JP2023044755A - Method for producing joint body and method for producing insulated circuit board - Google Patents

Abstract

To uniformly pressurize a laminate of different plate members and producing an excellent joint body when joining them in a pressurized and heated state, and prevent foreign matter from depositing on the surface of the laminate.SOLUTION: The present invention provides a method for producing a joint body by pressurizing and heating a laminate, which comprises a first plate member and a second plate member, with a spacer brought into contact with the surface of the first plate member. The first plate member is a metal plate. In the spacer, at least a contact part with the first plate member is composed of a stainless plate comprising molybdenum of 2.0 mass% or more. The stainless plate has a thickness of 0.2 mm or more and 1.0 mm or less.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a bonded body composed of a plurality of different plate members, such as a power module substrate, and in particular, a manufacturing method suitable for bonding metal plates together by solid phase diffusion bonding, and a bonded body thereof. It relates to a method for manufacturing an insulated circuit board using the manufacturing method of

Power module substrates (insulated circuit substrates) generally have a structure in which a circuit layer is formed on one side of a ceramic substrate that serves as an insulating layer, and a heat dissipation layer is formed on the other side for heat dissipation. be done.

As this power module substrate, for example, Patent Document 1 discloses a power module substrate. This power module substrate has a circuit layer on one side of the ceramic substrate and a circuit layer on the other side by bonding metal plates made of aluminum, aluminum alloy, copper, or copper alloy to both surfaces of the ceramic substrate via brazing filler metal. A heat dissipation layer is formed on the surface of A heat dissipation plate made of aluminum or an aluminum alloy, or copper or a copper alloy is joined to the heat dissipation layer.

In this power module substrate, the ceramic substrate and the metal plate are joined together by applying pressure and heat to the laminate using a pressure device. At this time, a spacer formed by stacking a carbon layer and a graphite layer is interposed between the laminate and the pressure device. In this case, the carbon layer is arranged on the laminate side.

JP 2016-63145 A

In some power module substrates of this type, the circuit layer has a two-layer structure of aluminum and copper. In order to manufacture a bonded body composed of a plurality of different metal plates, a copper layer is formed by bonding a copper plate to an aluminum layer formed on a ceramic substrate by the method described in Patent Document 1. Solid-phase diffusion bonding, in which pressure and heat are applied without using a brazing material, may be used for bonding.

In this case, it is required to apply pressure more uniformly than bonding via a brazing material. If there is little displacement due to the application of a load, and if the surface of the laminate has minute unevenness or the flatness is large, these cannot be absorbed and pressure is not applied uniformly, which may result in poor bonding. be.

Furthermore, when the surface of the spacer in contact with the laminate is formed of a carbon layer, when this carbon layer is pressed while being heated together with the laminate, grain shedding occurs locally, and the carbon layer is formed on the surface of the laminate. part of may adhere. Even if a soft etching process is performed on the surface of the bonded body to remove the foreign matter, the foreign matter cannot be completely removed, resulting in a problem that a semiconductor element or the like cannot be mounted on the laminated body (on the circuit layer) after bonding.

On the other hand, if a strong etching treatment is applied to remove foreign matter, the surface of the laminated body after bonding becomes rough, and in this case also a semiconductor element or the like cannot be mounted on the circuit layer.

The present invention has been made in view of such circumstances, and when a laminate of a plurality of different plate members is joined under pressure and heat, the laminate is uniformly pressurized to produce a good joined body. It is also intended to prevent foreign matter from adhering to the surface of the laminate.

In the method for producing a joined body of the present invention, the laminated body is joined by pressing and heating the laminated body of the first plate member and the second plate member while the spacer is in contact with the surface of the first plate member. In the method for manufacturing a bonded body for manufacturing a body, the first plate member is a metal plate, and the spacer contains 2.0% by mass or more of molybdenum at least at a contact portion with the first plate member. It is made of a stainless steel plate, and the thickness of the stainless steel plate is 0.2 mm or more and 1.0 mm or less.

Since the contact portion of the spacer with the first plate member is made of a stainless steel plate containing 2.0% by mass or more of molybdenum (Mo), when the laminate is pressurized and heated through this spacer, the contact of the spacer can be suppressed from adhering to the surface of the first plate member of the laminate.

Further, when the thickness of the stainless steel plate of the spacer exceeds 1.0 mm, if the thermal expansion coefficient differs from that of the first plate member of the laminate, the spacer and the first plate member may be separated from each other during heating and cooling due to the difference in thermal expansion coefficient. A stress along the surface direction is generated between the first plate member and the first plate member. . Further, if the thickness of the stainless steel plate is less than 0.15 mm, the stainless steel plate will be deformed when the laminate is pressurized, making it difficult to reuse.
By setting the thickness of the stainless steel plate to 0.2 mm or more and 1.0 mm or less, the stainless steel plate follows the thermal expansion and contraction of the first plate member of the laminate during pressurization and heating, and the first plate member and the second plate are separated. It can be reused without destroying the joint interface with the member and suppressing deformation of itself.

In the method for manufacturing a joined body of the present invention, the stainless steel plate forming the contact portion is preferably JIS SUS316.
SUS316 has an appropriate molybdenum content and is widely used for various purposes, so it is easy to obtain and is advantageous in terms of cost.

In the present invention, one of the first plate member and the second plate member can be made of copper or a copper alloy, and the other can be made of aluminum or an aluminum alloy.

Aluminum and copper are generally bonded by solid-phase diffusion bonding, and the present invention is particularly effective for such solid-phase bonding. However, liquid phase bonding using a brazing material is not excluded. For example, the present invention can be applied to a case where the first plate member is made of a metal plate and the second plate member is made of a ceramic substrate and these are joined together using a brazing material.

A method for manufacturing an insulated circuit board according to the present invention is a method for manufacturing an insulated circuit board using the above-described method for manufacturing a joined body, wherein the first plate member is a first metal plate made of copper or a copper alloy. The second plate member comprises a ceramic substrate and a second metal plate made of aluminum or an aluminum alloy bonded to one surface of the ceramic substrate, and the second metal plate bonded to the ceramic substrate The first metal plate is laminated to form the laminate, and the first metal plate and the second metal plate are solid-phase diffusion-bonded while the stainless steel plate is in contact with the first metal plate.

Another method for manufacturing an insulated circuit board is a method for manufacturing an insulated circuit board using the above-described method for manufacturing a joined body, wherein two sets of the spacers are used, and the first plate member is made of copper or a copper alloy. and an AlSiC composite material obtained by impregnating a porous silicon carbide body with a metal containing aluminum as a main component, and the second plate member is a ceramic substrate and the ceramic substrate and the first metal plate laminated on one of the second metal plates, the second metal on the other of the second plate members The laminate is formed by laminating the first plate member and the second plate member by bringing the plate and the first metal plate of the first plate member into contact with each other, and the AlSiC composite material is provided with one of the With the stainless plate of the spacer in contact and the stainless steel plate of the other spacer in contact with the surface of the first metal plate of the second plate member, the first metal plate and the second metal The plate, and the first metal plate and the AlSiC composite material are simultaneously solid phase diffusion bonded.

According to the method for manufacturing a joined body of the present invention, when a laminated body of a plurality of different plate members is pressurized and joined in a heated state, a uniform pressure is applied to the laminated body to produce a good joined body. At the same time, it is possible to prevent foreign matter from adhering to the surface of the laminate.

1 is a sectional view showing a power module substrate as an embodiment of a bonded body (insulated circuit substrate) of the present invention; FIG. 2 is a cross-sectional view showing a state before joining a metal plate to a ceramic substrate of the power module substrate in FIG. 1; FIG. FIG. 3 is a cross-sectional view showing a state before joining a second metal plate to the metal layer after joining from FIG. 2 ; FIG. 4 is a front view of a pressurizing device used for joining of FIGS. 2 and 3; FIG. 5 is a cross-sectional view of a spacer used in the pressure device of FIG. 4; FIG. 11 is a cross-sectional view showing a state before bonding when manufacturing another power module substrate.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
This embodiment is a power module board 1 as an example of an insulated circuit board (bonded body). As shown in FIG. 1, the power module substrate 1 includes a ceramic substrate 10, a circuit layer 20 bonded to one surface of the ceramic substrate 10, and a heat dissipation layer bonded to the other surface of the ceramic substrate 10. 30.

For the ceramic substrate ₁₀ , for example, nitride ceramics such as AlN (aluminum nitride) and _Si3N4 (silicon nitride), or oxide ceramics such _{as Al2O3} (alumina) can be used. Moreover, the thickness of the ceramics substrate 10 is set to 0.2 mm or more and 1.5 mm or less.

The circuit layer 20 and the heat dissipation layer 30 each have a two-layer structure of a second metal layer 41 made of aluminum or an aluminum alloy and a first metal layer 42 made of copper or a copper alloy. In other words, in the power module substrate 1 , the second metal layer 41 is formed on both surfaces of the ceramic substrate 10 , and the first metal layer 42 is formed on the second metal layer 41 .

The second metal layer 41 is made of pure aluminum with a purity of 99% by mass or more (for example, pure aluminum in the 1000s according to JIS standards, particularly 1N90 (purity of 99.9% by mass or more: so-called 3N aluminum) or 1N99 (purity of 99.99 mass % or more: so-called 4N aluminum), aluminum alloys such as A6063 series, etc. In order to buffer the difference in thermal expansion and contraction between the first metal layer 42 and the ceramic substrate 10, the second metal layer 41 It is preferred to use pure aluminum.

The first metal layer 42 is preferably made of copper (oxygen-free copper) with a purity of 99.96% by mass or more or copper (tough pitch copper) with a purity of 99.90% by mass or more, for example.

Although the thicknesses of the second metal layer 41 and the first metal layer 42 are not limited, for example, the thickness of the second metal layer 41 is 0.1 mm or more and 2.0 mm or less, and the thickness of the first metal layer 42 is 0.2 mm or more and 5.0 mm. It is assumed that: The second metal layer 41 and the first metal layer 42 having the same thickness may be used for the circuit layer 20 and the heat dissipation layer 30, or a combination of different thicknesses may be used. In the illustrated example, the second metal layer 41 and the first metal layer 42 are denoted by the same reference numerals without distinction between the circuit layer 20 and the heat dissipation layer 30 .

A method of manufacturing the power module substrate 1 configured in this way will be described.

First, as shown in FIG. 2, a second metal plate 41a made of aluminum or an aluminum alloy is laminated on both sides of the ceramic substrate 10 via a brazing material 50, and the laminate is heated under pressure to form the ceramic substrate 10. and the second metal plate 41a are joined to form the second metal layer 41 on both surfaces of the ceramic substrate 10 (first joining step).

Next, as shown in FIG. 3, a first metal plate 42a made of copper or a copper alloy is laminated on the second metal layer 41, and the laminate is heated under pressure to solidify aluminum and copper. Phase diffusion bonding is performed to form the first metal layer 42 on the second metal layer 41 (second bonding step).

The present invention is applied to both of these joining processes.
In the first bonding step, the second metal plate 41a corresponds to the first plate member of the invention, and the ceramic substrate 10 corresponds to the second plate member of the invention. On the other hand, in the second bonding step, the first metal plate 42a corresponds to the first plate member of the present invention, and the ceramic substrate 10 and the second metal plate 41a (second metal plate 41a) bonded to one surface of the ceramic substrate 10 The metal layer 41) corresponds to the second plate member of the present invention.

In this manufacturing method, a pressurizing device 110 shown in FIG. 4 is used to pressurize the laminate in the first bonding step and the laminate in the second bonding step. In the following, the laminate in the first bonding step (laminate consisting of the ceramic substrate 10 and both second metal plates 41a) and the laminate in the second bonding step (ceramic substrate 10 on which both second metal layers 41 are formed and , and the first metal plate 42a) will be described as a laminate S without distinction.

The pressure device 110 includes a base plate 111, guide posts 112 vertically attached to the four corners of the upper surface of the base plate 111, fixed plates 113 fixed to the upper ends of the guide posts 112, and the base plate 111. A pressing plate 114 supported by the guide post 112 so as to be vertically movable between the fixing plate 113 and a spring or the like provided between the fixing plate 113 and the pressing plate 114 to bias the pressing plate 114 downward. A force portion 115 is provided.

The fixing plate 113 and the pressing plate 114 are arranged parallel to the base plate 111 , and the laminate S is arranged between the base plate 111 and the pressing plate 114 .
Spacers 60 are provided on the sides of the base plate 111 and the pressing plate 114 that are in contact with the laminate S for uniform pressure application.

Each spacer 60 has a structure in which a graphite sheet 61 and a stainless steel plate 62 are laminated, as shown in FIG.
The graphite sheet 61 is made of a flexible graphite material having cushioning properties and is constructed by laminating a plurality of scale-like graphite thin films like mica. It is made by roll rolling. The graphite sheet 61 has a bulk density of 0.5 Mg/m ³ or more and 1.3 Mg/m ³ or less and is soft. For example, T-5 manufactured by Asahi Graphite Co., Ltd. (thermal conductivity: 75.4 W / mK, elastic modulus: 11.4 GPa), graphite sheet PF manufactured by Toyo Tanso Co., Ltd. (compression rate 47%, recovery rate 14%), etc. can be used.

The stainless steel plate 62 is selected to contain at least 2.0% by mass of molybdenum (Mo), preferably JIS (Japanese Industrial Standard) SUS316.
The stainless plate 62 containing 2.0% by mass or more of molybdenum does not react with the surface of the laminate S when heated. "No reaction" means that there is no peeling when cooling from the bonding temperature to room temperature and no intermetallic compound is formed between the metal plate and the surface of the laminate. If the content of molybdenum is less than 2.0% by mass, it may react with the metal plate on the surface of the laminate due to heat during bonding.

The thickness of this stainless steel plate 62 is set to 0.2 mm or more and 1.0 mm or less. By setting the thickness within this range, the stainless steel plate 62 follows the thermal expansion and contraction of the second metal plate 41a or the first metal plate 42a of the laminate S during pressurization and heating in the bonding process. It can be reused without destroying the joint with the two metal plates 41a or the joint interface between the second metal layer 41 and the first metal plate 42a, and suppressing deformation of itself.
Although the thickness of the graphite sheet 61 is not particularly limited, it is, for example, 0.5 mm or more and 5.0 mm or less.

A first bonding process and a second bonding process using the pressure device 110 will be described in order below.

(First joining step)
As shown in FIG. 2, a laminate S is formed by laminating a second metal plate 41a made of aluminum or an aluminum alloy on both surfaces of the ceramic substrate 10 with brazing material 50 interposed therebetween. As the brazing material 50, an alloy such as Al--Si system, Al--Ge system, Al--Cu system, Al--Mg system or Al--Mn system is used.

The second metal plate 41a is bonded to the ceramic substrate 10 by pressing the laminate S in the stacking direction using the pressure device 110 shown in FIG. A second metal layer 41 is formed on both surfaces of the ceramic substrate 10 . At this time, the spacer is arranged so that the metal plate contacts the second metal plate.

At this time, the pressure is, for example, 0.1 MPa or more and 3.4 MPa or less, the bonding temperature is 600° C. or more and 655° C. or less, and the heating time is 15 minutes or more and 120 minutes or less.

(Second joining step)
As shown in FIG. 3, a laminate S is formed by laminating first metal plates 42a made of copper or a copper alloy on the second metal layers 41 formed on both surfaces of the ceramic substrate 10, respectively.

While the laminate S is pressurized in the stacking direction using the pressurizing device 110 shown in FIG. are respectively solid phase diffusion bonded to form the first metal layer 42 on the second metal layer 41 .

In this case, the pressure is 0.3 MPa or more and 3.5 MPa or less, and the heating temperature is 400° C. or more and less than 548° C., for example. By maintaining this pressurized and heated state for 5 minutes or more and 240 minutes or less, the second metal layer 41 and the first metal plate 42a are solid phase diffusion bonded, and the first metal layer 42 is formed on the second metal layer 41. is formed.

As described above, in the pressurizing device 110 of this embodiment, the spacer 60 is provided between the laminate S in which the first metal plate 42a is laminated on the second metal layer 41, the base plate 111, and the pressing plate 114. , and a stainless steel plate 62 is arranged on the side of the contact surface of the spacer 60 with the laminate S. As shown in FIG.

Since the stainless plate 62 is made of a ductile material, even if the surface of the laminate S is uneven or the flatness thereof is low, the stainless plate 62 is deformed so as to follow the shape of the surface. Therefore, a uniform pressure can be applied to the entire surface of the laminate S, and the entire surface can be evenly bonded. In addition, since it is not a brittle material like a carbon sheet, it is not damaged by pressure and does not react with the first metal plate 42a provided on the surface of the laminate S, so it adheres to the first metal plate 42a. I don't even have to.

Further, since the thickness of the stainless steel plate 62 of the spacer 60 is formed to be 0.2 mm or more and 1.0 mm or less, the stainless steel plate 62 of the spacer 60 and the metal plates 41a, 42a of the laminate S are crimped during bonding. is suppressed.
That is, the stainless steel plate 62 forming the contact portion of the spacer 60 and the metal plates 41a and 42a of the laminate S have different coefficients of thermal expansion. , the stainless steel plate 62 of the spacer 60 and the metal plates 41a, 42a of the laminate S are in close contact with each other. A large stress along the surface direction is generated between the laminate S and the metal plates 41 a and 42 a , and this stress may destroy the bonding interface with the ceramic substrate 10 to be bonded and the second metal layer 41 .

In this respect, by setting the thickness of the stainless plate 62 of the spacer 60 to 1.0 mm or less, the stainless plate 62 is deformed so as to follow the difference in thermal expansion coefficient between the metal plates 41a and 42a of the laminate S. , it is possible to suppress the state of being crimped with the laminated body S, and to perform good bonding.
Moreover, if the thickness of the stainless steel plate 62 is 1.0 mm or less, there is no possibility that the graphite sheet 61 will be crushed.

However, if the stainless steel plate 62 is too thin, the carbon sheet 61 has a cushioning property, and is easily deformed by being pressed by the laminate S during pressurization. In particular, since the stainless plate 62 is wider than the laminate S, the stainless steel plate 62 is bent by the periphery of the laminate S, and the portion protruding from the laminate S is inclined with respect to the portion pressed against the laminate S. There is a risk of deformation. This spacer 60 is used repeatedly when manufacturing a plurality of joined bodies, and if large deformation occurs, the laminated body S cannot be uniformly pressurized the next time it is used. In order to suppress the deformation of the stainless plate 62, the thickness of the stainless plate 62 is preferably 0.2 mm or more.

As described above, by using the pressure device 110 provided with the spacer 60, it is possible to manufacture a high-quality power module substrate (insulated circuit substrate) 1 free from poor bonding.

The present invention is not limited to the configurations of the above embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, the manufacturing method of the present invention can be applied to the case of forming a circuit layer having a two-layer structure of an aluminum layer and a copper layer on one side of a ceramic substrate, and on the other side of the ceramic substrate, as in the embodiment. It is not necessary to have a two-layered heat dissipation layer. In this case, the spacer in contact with the ceramic substrate 10 does not have to have the stainless steel plate 62 .

The production method of the present invention may be applied not only to joining a metal plate made of copper or a copper alloy and a metal plate made of aluminum or an aluminum alloy, but also to joining an AlSiC composite material and copper or a copper alloy.

The AlSiC composite is a composite of aluminum and silicon carbide formed by impregnating a porous body made of silicon carbide (SiC) with a metal containing aluminum (Al: pure aluminum or an aluminum alloy) as a main component. A coating layer of aluminum is formed on the surface of .

When using this AlSiC composite material, as shown in FIG. 6, on each second metal layer 41 formed on both sides of the ceramic substrate 10, a first metal plate 42a made of copper or a copper alloy is laminated. , a plate-like AlSiC composite material 70 is laminated on one of the first metal plates 42a to form a laminate.

With respect to this laminate, the stainless steel plate 62 of the spacer 60 is in contact with the surface of the AlSiC composite material 70, and the stainless steel plate 62 of the spacer 60 is in contact with the surface of the first metal plate 42a. are pressed in the stacking direction and heated in a vacuum atmosphere, the second metal layer 41 and the first metal plate 42a, and the first metal plate 42a and the AlSiC composite material 70 are simultaneously solid-phase diffused. Can be spliced.

In this case, a circuit layer and a heat dissipation layer each comprising a first metal layer and a second metal layer are formed on a ceramic substrate by the method described in the above embodiment, and an AlSiC composite material is applied to the first metal layer of the heat dissipation layer as a heat sink. It can be an insulated circuit board that is bonded as an insulated circuit board.

That is, a second metal layer is formed on both sides of the ceramic substrate (by the first bonding step), each first metal plate is laminated on each second metal layer, and one of the first metal plates is AlSiC composite It is preferable that the materials are laminated and the laminated body is pressurized and heated for solid-phase diffusion bonding (second bonding step).

In addition, the present invention is not limited to the circuit layer and the heat dissipation layer of the power module substrate, and can be applied to a combination of metals that can be bonded in a liquid phase and a solid phase. Effective for combinations. The present invention can also be applied to bonding between a metal plate and a plate member other than the metal plate (for example, a ceramic substrate).

An evaluation test was conducted to confirm the effects of the present invention. In this test, a metal plate made of aluminum alloy (A6063) and a metal plate made of pure copper (C1020) were laminated and joined. The metal plate on the side in contact with the spacer was used as an adherend.

The spacer had a laminate structure of a graphite sheet (PF-100 manufactured by Toyo Tanso Co., Ltd.) and a stainless steel plate as a contact portion. Any one of SUS304, SUS316, SUS316L, SUS317L, and SUS430 was used for the stainless steel plate. As a conventional example, a test was also conducted using a SUS304 foil (thickness: 0.15 mm). The molybdenum (Mo) content and thickness were as shown in Table 1.

A laminate of both metal plates was heated under pressure of 1.0 MPa at a temperature of 500° C. for a holding time of 30 minutes, and the deformation, adhesion and bondability (followability) of the metal plates of the spacer were evaluated.

(Evaluation of spacer deformation)
When the spacer is peeled off from the adherend after bonding, cracking or deformation (deformation to the extent that it cannot be reused, such as being bent at the edge of the adherend) occurs in the spacer. A case where no deformation occurred was rated as "A".

(Evaluation of Spacer Adhesion)
Regarding the adhesion of the spacer, it was confirmed that the metal plate was cooled to room temperature after bonding, the metal plate could be manually peeled off from the laminate, and the cross section of the metal plate and the laminate surface was observed with an SEM, and the metal plate and the laminate surface were examined. A case where no intercalation compound was produced was evaluated as "A", and a case other than that was evaluated as "B".

(Evaluation of bondability)
Bondability is determined by observing the interface between both metal layers using an ultrasonic flaw detector (FINESAT manufactured by Hitachi Power Solutions Co., Ltd.), measuring the area to be bonded, and determining the area to be bonded before bonding (area of metal layer). The bonding rate was determined, and the bonding rate was 95% or more as "A", and less than 95% as "B".
These results are shown in Table 1. Any evaluation also sets "A" as a pass.

As shown in Table 1, in the examples using a stainless steel plate containing 2% by mass or more of molybdenum as the contact portion of the spacer, there was no deformation of the spacer or pressure bonding with the adherend after bonding, and the bondability was good. Met.
On the other hand, in Comparative Examples 1 and 2, since the molybdenum content of the stainless steel plate was 0% by mass, the stainless steel plate was crimped to the adherend during bonding. Also in Comparative Example 2, since the molybdenum content of the stainless steel plate was 0% by mass, pressure bonding with the adherend was observed during bonding. In Comparative Example 3, the molybdenum content of the stainless steel plate was 2.5% by mass, but because the thickness was as thin as 0.15 mm, deformation due to pressurization was observed. In Comparative Example 4, on the contrary, the thickness of the stainless steel plate was as large as 1.2 mm, resulting in poor bondability. In the conventional example, both deformation and crimping due to pressurization were observed.

1 Substrate for power module (joint) (insulated circuit substrate)
10 ceramic substrate (second plate member)
20 circuit layer 30 heat dissipation layer 41 second metal layer (second plate member)
41a second metal plate (first plate member/second plate member)
42 first metal layer 42a first metal plate (first plate member)
50 Brazing material 60 Spacer 61 Graphite sheet 62 Stainless steel plate 70 AlSiC composite material 110 Pressure device

Claims (5)

A method for manufacturing a joined body, wherein the laminated body of a first plate member and a second plate member is pressurized and heated while a spacer is in contact with the surface of the first plate member to produce a joined body. The first plate member is a metal plate, and the spacer is made of a stainless steel plate containing 2.0% by mass or more of molybdenum at least at a contact portion with the first plate member, and the thickness of the stainless steel plate is A method for producing a joined body, characterized in that the thickness is 0.2 mm or more and 1.0 mm or less. 2. The method of manufacturing a joined body according to claim 1, wherein the stainless steel plate forming said contact portion is JIS SUS316. 3. The manufacturing of the joined body according to claim 1, wherein one of the first plate member and the second plate member is made of copper or a copper alloy, and the other is made of aluminum or an aluminum alloy. Method. A method for manufacturing an insulated circuit board using the method for manufacturing a joined body according to any one of claims 1 to 3,
The first plate member is made of a first metal plate made of copper or a copper alloy,
The second plate member comprises a ceramic substrate and a second metal plate made of aluminum or an aluminum alloy bonded to one surface of the ceramic substrate,
The first metal plate is laminated on the second metal plate bonded to the ceramic substrate to form the laminate, and the first metal plate and the stainless steel plate are in contact with the first metal plate. A method for manufacturing an insulated circuit board, characterized in that solid-phase diffusion bonding is performed to the second metal plate. A method for manufacturing an insulated circuit board using the method for manufacturing a joined body according to any one of claims 1 to 3,
Using two pairs of the spacers,
The first plate member is formed by laminating a first metal plate made of copper or a copper alloy and an AlSiC composite material obtained by impregnating a porous body of silicon carbide with a metal containing aluminum as a main component,
The second plate member comprises a ceramic substrate, a second metal plate made of aluminum or an aluminum alloy bonded to both surfaces of the ceramic substrate, and the first metal plate laminated on one of the second metal plates. become,
The laminate by laminating the first plate member and the second plate member by bringing the other second metal plate of the second plate member and the first metal plate of the first plate member into contact with each other to form
With the stainless steel plate of one spacer in contact with the AlSiC composite material and the stainless steel plate of the other spacer in contact with the surface of the first metal plate of the second plate member, the second A method for manufacturing an insulated circuit board, characterized in that the first metal plate and the second metal plate, and the first metal plate and the AlSiC composite material are simultaneously solid-phase diffusion-bonded.

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