TW202110776A - Copper/ceramic joined body, insulating circuit substrate, copper/ceramic joined body production method, and insulating circuit substrate production method - Google Patents

Abstract

The copper/ceramic joined body (10) is obtained by joining a copper member (12, 13) comprising copper or a copper alloy and a ceramic member (11) comprising silicon nitride, an Mg-N compound phase (41) extending from the ceramic member (11) side toward the copper member (12, 13) side is present at the joining interface between the copper member (12, 13) and the ceramic member (11), and at least a portion of the Mg-N compound phase (41) penetrates the copper member (12, 13).

Description

Copper/ceramic joint body, insulated circuit board, and copper/ceramic joint body manufacturing method, insulated circuit board manufacturing method

This invention relates to an insulated circuit board formed by bonding a copper member made of copper or copper alloy, a copper/ceramic bonding body for bonding a ceramic member, and a copper plate made by bonding copper or a copper alloy on the surface of a ceramic substrate, and, copper/ Manufacturing method of ceramic joint body, manufacturing method of insulated circuit board. The present invention claims priority based on Japanese Patent Application No. 2019-151143 filed in Japan on August 21, 2019 and Japanese Patent Application No. 2020-134035 filed in Japan on August 6, 2020, and this content is used for this.

In power modules, LED modules, and thermoelectric modules, on one side of the insulating layer, an insulating circuit substrate with a circuit layer made of conductive material is formed to join power semiconductor components, LED components, and thermoelectric components. For example, the power semiconductor components used to control the large power control used in wind power generation, electric vehicles, and hybrid vehicles have a large amount of heat during operation. As the substrate on which this is mounted, a ceramic substrate is provided. An insulated circuit board in which a circuit layer is formed by bonding metal plates with excellent conductivity on one side of a ceramic board has been widely used in the past. As an insulated circuit substrate, there are also those formed by joining metal plates on the other side of the ceramic substrate.

For example, Patent Document 1 proposes an insulated circuit board in which a circuit layer and a metal layer are formed by bonding copper plates on one surface and the other surface of a ceramic substrate. In this Patent Document 1, a copper plate is arranged on one surface and the other surface of a ceramic substrate via an Ag-Cu-Ti-based solder material, and the copper plates are joined by heat treatment (so-called active metal brazing method). In this active metal brazing method, the active metal containing Ti-containing welding material is used, which can improve the wettability of the molten welding material and the ceramic substrate, and can well join the ceramic substrate and the copper plate.

In addition, Patent Document 2 proposes an insulated circuit board that uses a Cu-Mg-Ti-based solder to join a ceramic substrate and a copper plate. In this patent document 2, it is formed by heating and bonding at 560-800°C in a nitrogen atmosphere. The Mg in the Cu-Mg-Ti alloy is sublimated and does not remain at the bonding interface, and titanium nitride (TiN) is essentially It will not be formed. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3211856 [Patent Document 2] Japanese Patent No. 4375730

[The problem to be solved by the invention]

However, in the circuit layer of the above-mentioned insulated circuit board, terminal materials and the like are sometimes bonded by ultrasonic waves. The insulated circuit boards described in Patent Documents 1 and 2 are for bonding terminal materials and the like. When ultrasonic waves are applied, cracks may occur at the bonding interface and the circuit layer may be peeled off.

This invention is made in view of the foregoing circumstances, and provides a copper/ceramic bonded body, an insulated circuit board, and, even when ultrasonic bonding is performed, which can suppress the peeling of the ceramic member and the copper member or the generation of cracks in the ceramic member The purpose is the manufacturing method of the copper/ceramic junction and the manufacturing method of the insulated circuit board. [Means to solve the problem]

In order to solve the aforementioned problems, the copper/ceramic joint body of one aspect of the present invention (hereinafter referred to as "the copper/ceramic joint body of the present invention") is a copper member formed by joining copper or a copper alloy, and a combination of silicon nitride In the copper/ceramic joined body formed into a ceramic member, at the bonding interface between the copper member and the ceramic member, there is a Mg-N compound phase extending from the ceramic member side to the copper member side, and the Mg-N compound At least a part of the phase is incorporated into the aforementioned copper member.

According to the copper/ceramic joint body of the present invention, at the joint interface between the copper member and the ceramic member, there is a Mg-N compound phase extending from the ceramic member side to the copper member side, and the Mg-N compound Since at least a part of the phase enters the aforementioned copper member, the Mg as the bonding material and the nitrogen of the ceramic member fully react, and the copper member and the ceramic member are strongly bonded. Then, through the anchoring effect of the Mg-N compound phase entering the copper component, even under the condition of ultrasonic loading, the separation of the ceramic component and the copper component can be suppressed, or the generation of cracks in the ceramic component can be suppressed.

In the copper/ceramic joint of the present invention, the number density of the Mg-N compound phase having a length of 100 nm or more in the longitudinal direction along the unit length of the joint interface is preferably 8 pieces/μm or more. At this time, ensure that the number of Mg-N compound phases fully grown from the ceramic member side to the copper member side can surely obtain the anchoring effect of the Mg-N compound phase entering the copper member, even in the case of ultrasonic loading Next, it can also suppress the peeling of the ceramic component and the copper component, or suppress the generation of cracks in the ceramic component.

In the copper/ceramic joint of the present invention, the Si concentration of the aforementioned Mg-N compound phase is preferably 25 atomic% or less. At this time, the Si single phase can be prevented from being locally precipitated in the Mg-N compound phase, and the strength of the Mg-N compound phase can be sufficiently ensured, and the anchoring effect of the Mg-N compound phase entering the copper member can be reliably obtained. Even in the case of ultrasonic loading, it can suppress the peeling of the ceramic component and the copper component, or suppress the generation of cracks in the ceramic component.

Another form of the insulated circuit board of the present invention (hereinafter referred to as "the insulated circuit board of the present invention") is an insulated circuit board formed by joining a copper plate made of copper or copper alloy on the surface of a ceramic substrate made of silicon nitride, At the bonding interface between the copper plate and the ceramic substrate, there is a Mg-N compound phase extending from the ceramic substrate side to the copper plate side, and at least a part of the Mg-N compound phase enters the copper plate.

According to the insulated circuit board of the present invention, at the bonding interface between the copper plate and the ceramic substrate, there is a Mg-N compound phase extending from the ceramic substrate side to the copper plate side, and at least a part of the Mg-N compound phase When entering the aforementioned copper plate, the Mg used as the bonding material and the nitrogen of the ceramic member fully react, and the copper plate and the ceramic substrate are strongly bonded. Then, through the anchoring effect of the Mg-N compound phase entering the copper plate, even under the condition of ultrasonic waves, the peeling of the ceramic substrate and the copper plate can be suppressed, or the generation of cracks of the ceramic substrate can be suppressed.

In the insulated circuit board of the present invention, the number density of the Mg-N compound phase having a length of 100 nm or more in the longitudinal direction along the unit length of the bonding interface is preferably 8 pieces/μm or more. At this time, ensure the number of Mg-N compound phases fully grown from the ceramic substrate side to the copper plate side, and the anchoring effect of the Mg-N compound phase entering the copper plate can be obtained reliably, even under ultrasonic loading. It can also inhibit the peeling of the ceramic substrate and the copper plate, or inhibit the generation of cracks in the ceramic substrate.

In the insulated circuit board of the present invention, the Si concentration of the aforementioned Mg-N compound phase is preferably 25 atomic% or less. At this time, the Si single phase can be prevented from being partially precipitated in the aforementioned Mg-N compound phase, and the strength of the aforementioned Mg-N compound phase can be fully ensured, and the anchoring effect of the Mg-N compound phase entering the aforementioned copper plate can be reliably obtained. In the case of loading ultrasonic waves, it can also suppress the peeling of the ceramic substrate and the copper plate, or suppress the generation of cracks in the ceramic substrate.

The method of manufacturing a copper/ceramic joint of another form of the present invention (hereinafter referred to as "the method of manufacturing a copper/ceramic joint of the present invention") is in the method of manufacturing the copper/ceramic joint of the above-mentioned copper/ceramic joint , Equipped with: a Mg arrangement process of arranging Mg between the copper member and the ceramic member, a lamination process of laminating the copper member and the ceramic member through Mg, and a process of laminating the Mg The above-mentioned copper component and the above-mentioned ceramic component are heated in a vacuum environment under pressure in the lamination direction. In the above-mentioned Mg arrangement process, the amount of Mg should be 0.34mg/cm ² or more and 4.35mg/ Within the range of cm ² or less, in the aforementioned joining process, the temperature rise rate in the temperature range from 480°C to 650°C is 5°C/min or higher, and the temperature is maintained at 650°C or higher for 30 minutes or more.

According to the manufacturing method of the copper/ceramic junction body with this structure, the amount of Mg in the aforementioned Mg placement process is within the range of 0.34 mg/cm ² or more and 4.35 mg/cm ² or less, so that the interface reaction can sufficiently obtain Cu- Mg liquid phase. Therefore, it is possible to surely join the copper member and the ceramic member. In the joining process, the temperature rise rate in the temperature range above 480°C and less than 650°C is 5°C/min or more, and the temperature above 650°C is maintained for 30 minutes or more. Therefore, the interface reaction can be maintained for a certain period of time or more. The required Cu-Mg liquid phase promotes uniform interfacial reaction and can surely form the Mg-N compound phase extending from the ceramic member side to the copper member side.

A method of manufacturing an insulated circuit board of another aspect of the present invention (hereinafter referred to as "the method of manufacturing an insulated circuit board of the present invention") is a method of manufacturing an insulated circuit board for manufacturing the above-mentioned insulated circuit board, including: the aforementioned copper plate and the aforementioned Between the ceramic substrates, the Mg arrangement process of arranging Mg, the lamination process of laminating the copper plate and the ceramic substrate with Mg interposed therebetween, and the copper plate and the ceramic substrate laminated with the Mg interposed, and pressing In the state of the lamination direction, heat treatment of the bonding process in a vacuum environment; in the foregoing Mg configuration process, the amount of Mg is ^{within the range of 0.34 mg/cm 2 to} 4.35 mg/cm ² and the foregoing bonding process , The temperature rise rate in the temperature range above 480°C and less than 650°C is 5°C/min or higher, and the temperature is maintained at 650°C or higher for 30 minutes or more.

When this configuration according to the manufacturing method of the insulating circuit board, the Mg configuration works, so that it becomes the amount of Mg in the range of ² or less of 0.34mg / cm ² or more 4.35 mg / cm, the interface reaction can be sufficiently obtained in the Cu-Mg solution phase. Therefore, the copper plate and the ceramic substrate can be reliably joined. In the joining process, the temperature rise rate in the temperature range above 480°C and less than 650°C is 5°C/min or more, and the temperature above 650°C is maintained for 30 minutes or more. Therefore, the interface reaction can be maintained for a certain period of time or more. The required Cu-Mg liquid phase promotes uniform interfacial reaction and can surely form the Mg-N compound phase extending from the ceramic substrate side to the copper plate side. [Effects of the invention]

According to the present invention, it is possible to provide a copper/ceramic joint body, an insulated circuit board, and a copper/ceramic joint body, which can suppress the peeling of the ceramic member and the copper member or the generation of cracks in the ceramic member even when ultrasonic bonding is performed. Manufacturing method, manufacturing method of insulated circuit board.

Hereinafter, the embodiments of the present invention will be described with reference to the attached drawings. Regarding the copper/ceramic bonding system of this embodiment, the ceramic substrate 11 as a ceramic member made of ceramics, and the copper plate 22 (circuit layer 12) and copper plate 23 (metal layer 13) as copper members made of copper or copper alloy are joined The insulated circuit board 10 made. In FIG. 1, a power module 1 equipped with an insulated circuit board 10 of this embodiment is shown.

This power module 1 includes an insulated circuit board 10 on which a circuit layer 12 and a metal layer 13 are arranged, and a semiconductor element 3 bonded to one side of the circuit layer 12 (upper side in FIG. 1) via a bonding layer 2 , And a heat sink 30 arranged on the other side of the metal layer 13 (the lower side in FIG. 1).

The semiconductor element 3 is made of a semiconductor material such as Si. The semiconductor element 3 and the circuit layer 12 are bonded via the bonding layer 2. The bonding layer 2 is composed of, for example, a Sn-Ag-based, Sn-In-based, or Sn-Ag-Cu-based solder material.

The heat sink 30 radiates heat from the aforementioned insulated circuit board 10. The heat sink 30 is made of copper or copper alloy. In this embodiment, it is made of phosphorous deoxidized copper. The heat sink 30 is provided with a flow path 31 for flowing a cooling fluid. In this embodiment, the heat sink 30 and the metal layer 13 are joined via a solder layer 32 made of a solder material. The solder layer 32 is formed of, for example, Sn-Ag-based, Sn-In-based, or Sn-Ag-Cu-based solder materials.

The insulated circuit board 10 of this embodiment is shown in FIG. 1, and includes a ceramic substrate 11, a circuit layer 12 disposed on one side of the ceramic substrate 11 (upper surface in FIG. 1), and a circuit layer 12 disposed on the ceramic substrate The metal layer 13 on the other side of 11 (bottom in FIG. 1).

The ceramic substrate 11 is made of silicon nitride (Si ₃ N ₄ ) with excellent insulation and heat dissipation properties. The thickness of the ceramic substrate 11 is, for example, set within a range of 0.2 mm or more and 1.5 mm or less. In this embodiment, it is set to 0.32 mm.

The circuit layer 12 is shown in FIG. 4, and one side of the ceramic substrate 11 (upper side in FIG. 4) is formed by bonding a copper plate 22 made of copper or copper alloy. In this embodiment, the circuit layer 12 is formed by bonding a copper plate 22 made of a rolled sheet of oxygen-free copper to a ceramic substrate 11. The thickness of the copper plate 22 used as the circuit layer 12 is set within the range of 0.1 mm or more and 2.0 mm or less, for example, and in this embodiment, it is set to 0.6 mm. As the copper plate 22, toughened copper can be used.

As shown in FIG. 4, the metal layer 13 is formed on the other surface of the ceramic substrate 11 (lower surface in FIG. 4) by bonding a copper plate 23 made of copper or copper alloy. In this embodiment, the metal layer 13 is formed by bonding a copper plate 23 made of a rolled sheet of oxygen-free copper to the ceramic substrate 11. The thickness of the copper plate 23 that becomes the metal layer 13 is set within a range of 0.1 mm or more and 2.0 mm or less, for example, and in this embodiment, it is set to 0.6 mm. As the copper plate 23, toughened copper can be used.

At the bonding interface between the ceramic substrate 11 and the circuit layer 12 (metal layer 13), as shown in FIG. 2A, there is a Mg-N compound phase 41 extending from the ceramic substrate 11 side toward the circuit layer 12 (metal layer 13) side . At least a part of the Mg-N compound phase 41 enters the circuit layer 12 (metal layer 13). The Mg-N compound phase 41 is formed by reacting magnesium (Mg) used as a bonding material with nitrogen (N) contained in the ceramic substrate 11. The Mg-N compound phase 41 is the area where Mg and N coexist. Let the total of Mg, N, and Si be 100 at%, the concentration of Mg is 40 at% to 65 at%, and the aspect ratio of the area (long The length in the side direction/length in the short side direction) is 1.2 or more.

In this embodiment, the number density of the aforementioned Mg-N compound phase 41 having a length of 100 nm or more in the longitudinal direction per unit length along the bonding interface is preferably 8 pieces/μm or more. The auxiliary line L in Fig. 2A shows the joining interface. In this embodiment, the detection position of the visual oxygen is the bonding interface (refer to FIG. 2B). The number density of the aforementioned Mg-N compound phase 41 having a length of 100 nm or more in the longitudinal direction is preferably 10 pieces/μm or more, more preferably 12 pieces/μm or more.

Hereinafter, the manufacturing method of the insulated circuit board 10 of this embodiment is demonstrated with reference to FIG. 3 and FIG. 4. FIG.

(Mg placement process S01) First, prepare _{a ceramic substrate 11 made of silicon nitride (Si 3} N ₄ ), as shown in FIG. 4, between the copper plate 22 that becomes the circuit layer 12 and the ceramic substrate 11, and becomes the metal layer 13 Between the copper plate 23 and the ceramic substrate 11, Mg is arranged separately. In this embodiment, the Mg foil 25 is arranged between the copper plate 22 used as the circuit layer 12 and the ceramic substrate 11 and between the copper plate 23 used as the metal layer 13 and the ceramic substrate 11. In the Mg placement process S01, the amount of Mg placed is within the range of ^{0.34 mg/cm 2} or more and 4.35 mg/cm ^{2 or less.} However, Mg-based amount or more preferably ² to 0.52mg / cm, more preferably 0.69 mg / cm ² or more. On the other hand, the amount of Mg arranged is ^{preferably 3.48 mg/cm 2} or less, more preferably 2.61 mg/cm ² or less.

(Laminated Engineering S02) Next, the copper plate 22 and the ceramic substrate 11 are laminated with the Mg foil 25 interposed therebetween, and the ceramic substrate 11 and the copper plate 23 are laminated with the Mg foil 25 interposed therebetween.

(Joining process S03) Next, the laminated copper plate 22, Mg foil 25, ceramic substrate 11, Mg foil 25, and copper plate 23 are pressurized in the lamination direction, and are heated in a vacuum furnace to join the copper plate 22 and the ceramic substrate 11 and the copper plate 23. . Here, the heat treatment conditions of the bonding process S03 are such that the temperature increase rate in the temperature range of 480°C or higher but less than 650°C is 5°C/min or higher, and the temperature is maintained at a temperature of 650°C or higher for 30 minutes or more. By specifying such heat treatment conditions, the Cu-Mg liquid phase can be maintained at a high temperature, promote the interface reaction, and form the Mg-N compound phase 41.

The temperature increase rate in the temperature range above 480°C but less than 650°C is preferably 7°C/min or more, more preferably 9°C/min or more. On the other hand, as the temperature increase rate in the temperature range above 480°C but less than 650°C, 15°C/min or less is preferable, and 12°C/min or less is more preferable. In addition, the holding temperature is preferably 700°C or higher, more preferably 750°C or higher. On the other hand, the holding temperature is preferably 850°C or lower, more preferably 830°C or lower. The holding time is preferably 45 minutes or more, more preferably 60 minutes or more. On the other hand, the holding time is preferably 180 minutes or less, more preferably 150 minutes or less.

The pressurized load of the joining process S03 should preferably be within the range of 0.049MPa or more and 3.4MPa or less. The vacuum degree of the bonding process S03 is preferably within the range of ^{1×10 -6} Pa or more and 5×10 ^{-2 Pa or less.}

As described above, the insulated circuit board 10 of this embodiment is manufactured through the Mg placement process S01, the lamination process S02, and the bonding process S03.

(Heat sink bonding process S04) Next, the heat sink 30 is joined to the other surface side of the metal layer 13 of the insulated circuit board 10. The insulated circuit board 10 and the heat sink 30 are laminated with a solder material interposed therebetween, and the insulated circuit board 10 and the heat sink 30 are solder-bonded to the heating furnace through the solder layer 32.

(Semiconductor Element Bonding Process S05) Next, on one surface of the circuit layer 12 of the insulated circuit board 10, the semiconductor element 3 is joined via solder. Through the above-mentioned project, the power module 1 shown in Fig. 1 is produced.

According to the insulated circuit board 10 (copper/ceramic bonded body) of this embodiment constructed as described above, at the bonding interface between the circuit layer 12 (and the metal layer 13) and the ceramic substrate 11, there is an extension extending from the ceramic substrate 11 side The Mg-N compound phase 41 facing the circuit layer 12 (and the metal layer 13) side. At least a part of this Mg-N compound phase 41 enters the circuit layer 12 (and the metal layer 13). Mg and ceramics as the bonding material The nitrogen of the substrate 11 is fully reacted, and the circuit layer 12 (and the metal layer 13) and the ceramic substrate 11 are strongly bonded. Then, through the anchoring effect of the Mg-N compound phase 41 entering the circuit layer 12 (and the metal layer 13), for example, in order to ultrasonically bond copper and other terminal materials to the circuit layer 12 (metal layer 13), even if it is insulated The circuit substrate 10 (copper/ceramic joint body) can still suppress the peeling of the circuit layer 12 (metal layer 13) and the ceramic substrate 11, or suppress the generation of cracks in the ceramic substrate 11 under the condition of ultrasonic loading.

In the insulated circuit board 10 of this embodiment, when the number density of the Mg-N compound phase 41 having a length of 100 nm or more along the unit length of the joint interface becomes 8 pieces/μm or more, it is secured from the ceramic substrate 11 side The number of fully grown Mg-N compound phases 41 toward the circuit layer 12 (and metal layer 13) can reliably obtain the anchoring effect of the Mg-N compound phase 41 entering the circuit layer 12 (and metal layer 13), even if In the case of ultrasonic loading, the separation of the ceramic substrate 11 and the circuit layer 12 (and the metal layer 13) can be suppressed, or the generation of cracks in the ceramic substrate 11 can be suppressed.

In the insulated circuit board 10 of this embodiment, the Si concentration of the Mg-N compound phase 41 is preferably 25 atomic% or less. The Si concentration system may be 9.7 atomic% or more, for example. At this time, the Si single phase can be prevented from being locally precipitated in the Mg-N compound phase 41, and the strength of the Mg-N compound phase 41 can be fully ensured, and the Mg- that enters the circuit layer 12 (and/or the metal layer 13) can be obtained reliably. The anchoring effect of the N compound phase 41 can inhibit the peeling of the ceramic substrate and the copper plate, or the generation of cracks in the ceramic substrate, even under ultrasonic loading.

According to the manufacturing method of the insulated circuit board 10 (copper/ceramic joint) of this embodiment, in the Mg placement process S01, the amount of Mg placed between the copper plate 22 (copper plate 23) and the ceramic substrate 11 is 0.34 mg/cm ² Within the range of above 4.35mg/cm ^{2 and} below, the necessary Cu-Mg liquid phase can be obtained by the interface reaction. Therefore, the copper plate 22 (copper plate 23) and the ceramic substrate 11 can be reliably bonded, and the bonding strength of the circuit layer 12 (and the metal layer 13) and the ceramic substrate 11 can be ensured.

In the bonding process S03, the temperature rise rate in the temperature range from 480°C to 650°C is 5°C/min or higher, and the temperature is maintained at a temperature of 650°C or higher for 30 minutes or more. Therefore, it can be used on copper plate 22 (copper plate 23) The Cu-Mg liquid phase required to maintain the interface reaction with the ceramic substrate 11 for more than a certain period of time promotes uniform interface reaction. Mg can be reliably formed at the bonding interface of the circuit layer 12 (and the metal layer 13) of the ceramic substrate 11 -N compound phase 41.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and can be appropriately changed without departing from the scope of the technical idea of the invention. For example, in the present embodiment, although a power module is constructed by mounting a semiconductor element on an insulated circuit board, it is described, but it is not limited thereto. For example, LED elements may be mounted on the circuit layer of the insulated circuit substrate to form an LED module, or thermoelectric elements may be mounted on the circuit layer of the insulated circuit substrate to form a thermoelectric module.

In the insulated circuit board of the present embodiment, it has been described that the circuit layer and the metal layer are made of a copper plate made of copper or a copper alloy, but it is not limited to this. For example, as long as the circuit layer and the ceramic substrate are composed of the copper/ceramic junction of the present invention, the material or bonding method of the metal layer is not limited. There may be no metal layer, or the metal layer may be made of aluminum or aluminum alloy. It is composed of a laminate of copper and aluminum. On the other hand, when the metal layer and the ceramic substrate are composed of the copper/ceramic junction of the present invention, the material or bonding method of the circuit layer is not limited. The circuit layer can be composed of aluminum or aluminum alloy, or it can be composed of copper and aluminum. The layered body is constituted.

In this embodiment, the structure of the Mg foil layered between the copper plate and the ceramic substrate in the Mg placement process is explained, but it is not limited to this. The Mg film is formed on the joint surface of the ceramic substrate and the copper plate. It is also possible to form a film by sputtering or vapor deposition. The coating material can also be coated with electropaste _{using Mg or MgH 2.} [Example]

Hereinafter, the results of confirmation experiments performed to confirm the effects of the present invention will be described.

(Example 1) First, a ceramic substrate (40 mm × 40 mm × 0.32 mm) made of _{silicon nitride (Si 3} N _{4) was prepared.} On both sides of the ceramic substrate, a copper plate (37mm×37mm×thickness 0.5mm) made of oxygen-free copper was combined with the copper plate and the ceramic substrate under the conditions shown in Table 1, to obtain the insulation of Examples 1-9 of the present invention and Comparative Example 1. Circuit board (copper/ceramic junction). The vacuum degree of the vacuum furnace at the time of joining is 2×10 ^-3 Pa.

For the resulting insulated circuit board (copper/ceramic joint), the presence or absence of the Mg-N compound phase at the joint interface, the number density of the Mg-N compound phase with a length of 100 nm or more in the longitudinal direction, the initial bonding rate, and ultrasonic bonding The evaluation is as follows.

(Mg-N compound phase) Observation samples were taken from the center of the obtained insulated circuit board (copper/ceramic joint), and the bonding interface between the copper plate and the ceramic substrate was used with a transmission electron microscope (Titan ChemiSTEM manufactured by FEI) at an acceleration voltage of 200 kV and a magnification of 20,000 When observing the 2μm×2μm area, there is a field where Mg and N coexist. In this field, let the total of Mg, N, and Si be 100 at%, and the concentration of Mg is 40 at% to 65 at%, and When the aspect ratio (length in the long-side direction/length in the short-side direction) of the area is 1.2 or more, it is judged that there is a Mg-N compound phase. In addition, under the same measurement field of view, the number density of the Mg-N compound phase with a length of 100 nm or more in the longitudinal direction was calculated along the unit length of the joint interface. In the measurement of the number density of the Mg-N compound phase with a length of 100 nm or more in the longitudinal direction, the oxidation detection position is the bonding interface between the copper plate and the ceramic substrate. The number density is calculated by the following formula. (Number Density) = (The total number of Mg-N compound phases with a length of 100 nm or more in the longitudinal direction of the measurement field)/(The length of the joint interface of the measurement field) The Mg-N compound phase system that exists in the boundary part of the measurement field and cannot be grasped as a whole is excluded from the number. The number density was measured in 5 fields of view, and the average value is shown in the table.

(Initial bonding rate) Evaluate the bonding rate between the copper board and the ceramic substrate. Specifically, on the insulated circuit board, the bonding rate of the interface between the copper board and the ceramic board was evaluated using an ultrasonic flaw detection device (FineSAT200 manufactured by Hitachi Power Solutions Co., Ltd.) and calculated from the following formula. The initial bonding area is the area to be bonded before bonding, that is, the area of the circuit layer. In the image of the ultrasonic flaw detection image binarization processing, the peeling is displayed as the white part in the joint part, so the area of this white part is the peeling area. (Joining rate)=((Initial joining area)-(Non-joining area))/(Initial joining area)×100

(Evaluation of Ultrasonic Joint) For the obtained insulated circuit board (copper/ceramic joint), an ultrasonic metal bonding machine (manufactured by Ultrasonic Industry Co., Ltd.: 60C-904) was used, and the copper terminal (10mm×5mm×1mm thickness) was KOPLUS 0.3mm Condition, perform ultrasonic welding. The copper terminals are joined in units of 10 each. After bonding, use an ultrasonic flaw detection device (FineSAT200 manufactured by Hitachi Power Solutions Co., Ltd.) to inspect the bonding interface between the copper plate and the ceramic substrate. Evaluate as "C" if there are more than 3 out of 10 peelings between the copper plate and the ceramic substrate or ceramic cracking, and those observing more than 1 out of 10 copper plates and the ceramic base plate or ceramic cracking. As "B", all 10 cases where no peeling of the copper plate and the ceramic substrate or ceramic cracking were observed were evaluated as "A". The evaluation results are shown in Table 1.

In Comparative Example 1 in which the temperature increase rate in the temperature range from 480°C to 650°C was 2°C/min, no Mg-N compound phase was formed at the joint interface. For this reason, the initial bonding rate is low. In addition, when ultrasonic bonding was performed, it was confirmed that there were many peelings between the copper plate and the ceramic substrate or ceramic cracks.

In contrast, in Examples 1 to 9 of the present invention in which the Mg-N compound phase is formed at the bonding interface, the initial bonding rate is high, and the ceramic substrate and the copper plate can be strongly bonded. Then, when ultrasonic bonding is implemented, there is little peeling between the copper plate and the ceramic substrate or the occurrence of ceramic cracking.

(Example 2) In the same manner as in Example 1, a ceramic substrate (40 mm × 40 mm × 0.32 mm) made of _{silicon nitride (Si 3} N _{4) was prepared.} On both sides of the ceramic substrate, a copper plate (37mm×37 mm×0.5mm thick) made of oxygen-free copper was joined to the copper plate and the ceramic substrate under the conditions shown in Table 2 to obtain the insulated circuit substrates of Examples 11-19 of the present invention ( Copper/ceramic junction). The vacuum degree of the vacuum furnace at the time of joining is 2×10 ^-3 Pa.

For the obtained insulated circuit board (copper/ceramic joint), the number density of the Mg-N compound phase with a length of 100nm or more in the longitudinal direction, the initial bonding rate, and the examples are shown for the presence or absence of the Mg-N compound phase at the bonding interface 1Evaluate in the same way. Furthermore, the Si concentration and the number of defects in the Mg-N compound phase are evaluated as follows.

(Si concentration of Mg-N compound phase) Observation samples were taken from the center of the obtained insulated circuit board (copper/ceramic joint), and the bonding interface between the copper plate and the ceramic substrate was used with a transmission electron microscope (Titan ChemiSTEM manufactured by FEI) at an acceleration voltage of 200 kV and a magnification of 20,000 Observe the area of 2μm×2μm, and there is an area where Mg and N coexist. In this area, the total of Mg, N, and Si is taken as 100 atomic%, and the Si concentration is measured. The Si concentration was measured in 5 fields of view, and the average value is shown in Table 2.

(Number of bad) For the obtained insulated circuit board (copper/ceramic joint), an ultrasonic metal bonding machine (manufactured by Ultrasonic Industry Co., Ltd.: 60C-904) was used, and the copper terminal (10mm×5mm×1.5mm thickness) was measured by KOPLUS 0.5mm Under the conditions, ultrasonic bonding is carried out. The copper terminals are joined in units of 10 each. After bonding, use an ultrasonic flaw detection device (FineSAT200 manufactured by Hitachi Power Solutions Co., Ltd.) to inspect the bonding interface between the copper plate and the ceramic substrate. If peeling or ceramic cracking is observed, it is regarded as "bad", and the number is shown in the table. 2.

Inventive examples 11-18 in which the Si concentration of the Mg-N compound phase is less than 25 at% are compared with the present invention example 19 in which the Si concentration of the Mg-N compound phase is more than 25 at%. The number of defects during ultrasonic bonding is less. Presumably, the reason is that the precipitation of the single Si phase is suppressed and the strength of the Mg-N compound phase is ensured.

As a result of the above, according to the present invention, it can be confirmed to provide a copper/ceramic bonded body, an insulated circuit board, and, even when ultrasonic bonding is performed, which prevents peeling of the ceramic member and the copper member or the generation of cracks in the ceramic member Manufacturing method of copper/ceramic junction, manufacturing method of insulated circuit board. [Industrial availability]

According to the system of the present invention, it is possible to provide a copper/ceramic joint body, an insulated circuit board, and a copper/ceramic joint body that suppress the generation of peeling of the ceramic member and the copper member or the generation of cracks in the ceramic member even when ultrasonic bonding is performed The manufacturing method, the manufacturing method of the insulated circuit board.

10: Insulated circuit board (copper/ceramic joint) 11: Ceramic substrate (ceramic component) 12: Circuit layer (copper component) 13: Metal layer (copper member) 41: Mg-N compound phase

[Fig. 1] A schematic explanatory diagram of a power module using an insulated circuit board according to an embodiment of the present invention. [FIG. 2A] Observation results (BF STEM image) of the bonding interface between the circuit layer (metal layer) of the insulated circuit substrate and the ceramic substrate of the embodiment of the present invention. [FIG. 2B] Observation results (oxygen distribution diagram) of the bonding interface between the circuit layer (metal layer) of the insulated circuit substrate and the ceramic substrate according to the embodiment of the present invention. [Fig. 3] A flowchart of a manufacturing method of an insulated circuit board related to an embodiment of the present invention. [Fig. 4] A schematic explanatory diagram of a method of manufacturing an insulated circuit board according to an embodiment of the present invention.

10: Insulated circuit board (copper/ceramic joint)

11: Ceramic substrate (ceramic component)

12: Circuit layer (copper component)

13: Metal layer (copper member)

41: Mg-N compound phase

L: Subsidy line

Claims (8)

A copper/ceramic joint body, a copper/ceramic joint body formed by joining a copper component made of copper or copper alloy and a ceramic component made of silicon nitride, and its characteristics are At the bonding interface between the copper member and the ceramic member, there is a Mg-N compound phase extending from the ceramic member side to the copper member side, and at least a part of the Mg-N compound phase enters the copper member. The copper/ceramic bonded body according to claim 1, wherein the number density of the Mg-N compound phase having a length of 100 nm or more in the longitudinal direction along the unit length of the bonding interface is 8 pieces/μm or more. The copper/ceramic joined body according to claim 1 or 2, wherein the Si concentration of the Mg-N compound phase is 25 atomic% or less. An insulated circuit substrate, an insulated circuit substrate formed by joining a copper plate made of copper or copper alloy on the surface of a ceramic substrate made of silicon nitride, and its characteristics are At the bonding interface between the copper plate and the ceramic substrate, there is a Mg-N compound phase extending from the ceramic substrate side to the copper plate side, and at least a part of the Mg-N compound phase enters the copper plate. The insulated circuit board according to claim 4, wherein the number density of the Mg-N compound phase having a length of 100 nm or more in the longitudinal direction along the unit length of the bonding interface is 8 pieces/μm or more. The insulated circuit board according to claim 4 or 5, wherein the Si concentration of the Mg-N compound phase is 25 atomic% or less. A method for manufacturing a copper/ceramic joint body, which is a method for manufacturing a copper/ceramic joint body of a copper/ceramic joint body as described in any one of claims 1 to 3, characterized by: The Mg arrangement process of arranging Mg between the ceramic members, the lamination process of laminating the copper member and the ceramic member with Mg interposed therebetween, and the copper member and the ceramic member laminated with the Mg interposed therebetween. The bonding process in which the pressure is applied to the lamination direction, and the heat treatment is performed in a vacuum environment; in the aforementioned Mg arrangement process, the amount of Mg should be within the range of ^{0.34 mg/cm 2} or more and 4.35 mg/cm ^{2 or less.} In the joining process, the temperature rise rate in the temperature range above 480°C but less than 650°C is 5°C/min or more, and the temperature above 650°C is maintained for more than 30 minutes. A method for manufacturing an insulated circuit board is the method for manufacturing an insulated circuit board as described in any one of claims 4 to 6, characterized by comprising: a Mg arrangement process of arranging Mg between the aforementioned copper plate and the aforementioned ceramic substrate, And a lamination process in which the copper plate and the ceramic substrate are laminated via Mg, and the copper plate and the ceramic substrate are laminated with Mg in the stacking direction under pressure in a vacuum environment , Heat treatment and bonding process; In the aforementioned Mg placement process, the amount of Mg should be ^{within the range of 0.34 mg/cm 2 to} 4.35 mg/cm ² and in the aforementioned bonding process, the temperature range between 480°C and less than 650°C While the heating rate is above 5℃/min, keep the temperature above 650℃ for more than 30min.

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