JP2022027647A - Bonding agent and use thereof - Google Patents

Abstract

To provide a bonding material (active metal wax material or metal paste) which can effectively bond even a thick copper plate to a ceramic substrate at a low temperature, and can form a joint layer (or copper-pasted board) which has excellent durable reliability (thermal shock resistance) and good appearance, a copper-pasted board formed by use of this bonding material, and a method for manufacture of the same.SOLUTION: A bonding agent contains: an inactive metal component (1) containing at least one kind selected from Ag and Cu, and Sn; and an active metal component (2) containing an active metal; and an organic vehicle (3). A composition ratio [unit: atm%] of Ag, Cu and Sn prepares a metal paste existing in an area surrounded by (Ag,Cu,Sn)=(74,0,26), (67,12,21), (58,25,17), (47,40,13), (43,46,11), (33,54,13), (23,62,15), (15,65,20), (0,59,41), (0,13,87), (35,13,52), (32,6,62) and (29,0,71) on triangular coordinates or at an outer edge thereof.SELECTED DRAWING: Figure 1

Description

INDUSTRIAL APPLICABILITY The present invention relates to a metal paste (bonding agent (bonding composition) or a bonding agent (bonding composition)) that can be used for bonding a bonding portion such as a circuit board used for a power module or the like (particularly, a copper-coated substrate (or a copper-coated circuit board)). Wax composition) and its uses.

Power modules such as IGBTs (Insulated Gate Bipolar Transistors) play a role in power conversion and control in various fields such as power generation equipment, automobiles (hybrid cars (HEV), etc.), railway vehicles, home appliances (air conditioners, etc.). As a circuit board for a power module, a circuit board (copper-pasted substrate or copper-pasted circuit board) in which a copper plate is bonded to an insulating substrate (ceramic substrate) is often used.

The ceramic substrate is made of alumina, aluminum nitride, silicon nitride, etc., and is used properly according to the requirements such as thermal conductivity and mechanical strength. A thick copper plate of about 0.1 to 0.5 mm is used as the copper plate bonded to the ceramic substrate, and is used as a copper circuit for connecting to a semiconductor element, a copper heat sink for radiating heat generated by the semiconductor element, and the like. It is joined.

The active metal method is generally adopted as a method for joining the ceramic substrate and the copper plate, and the copper-clad substrate by the active metal method is called an AMC (Active Metal Brazed Copper) substrate. The active metal method is a method of joining a ceramic substrate and a copper plate by brazing using a brazing material (active metal brazing material) in which an active metal such as Ti or Zr is added to a main component such as Ag. As a mechanism, the active metal in the brazing material preferentially diffuses to the bonding interface with the ceramic substrate and reacts with N, O, Si, etc. in the ceramic substrate to form an active metal compound, and this active metal compound is formed. A brazing metal layer mainly containing a brazing material main component (Ag or the like) is interposed between the active metal compound layer mainly containing the above and the copper plate, and both of the different materials are bonded to each other. That is, the bonding layer interposed between the ceramic substrate and the copper plate is formed by a two-layer structure consisting of an active metal compound layer located on the ceramic substrate side and a brazing material layer located on the copper plate side. As an active metal brazing material for forming such a bonding layer, a brazing material containing Ag, Cu, Sn and Ti and the like are known.

For example, Japanese Patent Application Laid-Open No. 2002-137974 (Patent Document 1) states that at least one selected from silver 75 to 89%, copper 1 to 23%, tin 1 to 5%, titanium, zirconium and hafnium as metal components. Disclosed is a method of joining a predetermined ceramic body and an oxygen-free copper plate at 800 to 830 ° C. using a bonding brazing material containing 1 to 6% of the active metal component of the above.

Further, in Japanese Patent Application Laid-Open No. 2014-90144 (Patent Document 2), a specific brazing material containing Ag and Cu as a brazing metal component and TiH ₂ as an active metal component is used, and the bonding temperature is 780 to 810 ° C. Disclosed is a method of joining a predetermined ceramic substrate to a copper circuit and a copper heat sink under specific conditions. In Examples 1, 2 and 5-10 of this document, Sn is further used as the brazing metal component.

Japanese Patent Application Laid-Open No. 2017-130686 (Patent Document 3) contains Ag, Cu, Sn or In, and Ti, and the content of Sn or In is 1% by mass or more and 15% by mass or less. A ceramic copper circuit board in which a predetermined ceramic substrate and a copper plate are bonded by a bonding layer and has a specific cross-sectional shape and characteristics is disclosed.

In International Publication No. 2019/022133 (Patent Document 4), Ag is 85.0 to 95.0 parts by mass, Cu is 5.0 to 13.0 parts by mass, and Sn or In is 0.4 to 2.0. Using a brazing material containing 1.5 to 5.0 parts by mass of parts by mass and 1.5 to 5.0 parts by mass of Ti with respect to a total of 100 parts by mass of Ag, Cu, and Sn or In, the bonding temperature is 770 to 900 ° C. under predetermined conditions. Discloses a method for manufacturing a ceramic circuit substrate, which comprises a step of joining a copper plate to the ceramic substrate.

International Publication No. 2018/199060 (Patent Document 5) discloses a predetermined ceramic circuit board in which a ceramic substrate and a copper plate are bonded via a brazing material containing Ag, Cu and an active metal, and the brazing material is disclosed. It is also stated that Sn is included.

Japanese Patent Application Laid-Open No. 2019-64865 (Patent Document 6) is characterized in that a brazing material is applied to at least one surface of a ceramic substrate so as to form a specific coated region and a non-coated region. A method for producing a bonded substrate is disclosed, and in the examples of this document, a paste-like active metal containing 85% by mass of silver, 7% by mass of copper, 5% by mass of tin, and 3% by mass of titanium. It is described that the contained brazing material was used.

As described above, the active metal brazing material is generally a paste-like composition in which an organic vehicle such as an organic solvent is mixed and dispersed in a powder such as metal particles or a metal compound containing a metal component in the brazing material (a paste-like composition). Often used in the form of metal paste).

On the other hand, power modules in recent years tend to be smaller (higher density) and higher in output, and higher heat dissipation characteristics are required in order to suppress the temperature rise of the mounted chip. Therefore, it is required to improve the heat dissipation property of the copper-coated circuit board as the circuit board for the power module, and it is considered to increase the heat radiation amount by making the bonded copper plate thicker.

However, thick copper causes problems in terms of bondability and reliability (durability reliability or heat impact resistance) such as peeling of the copper plate and cracking of the ceramic substrate. That is, since there is a large difference in the thermal expansion coefficient between the copper plate, which is a different material, and the ceramic substrate, thermal stress (thermal expansion difference) occurs due to the thermal cycle due to the switching (on / off) operation during operation. This thermal stress causes the above-mentioned malfunction. This thermal stress becomes even greater due to the thickening of copper, and a particularly large thermal stress is applied to the joint layer (joint portion) that joins the two, so it is difficult to satisfy high heat dissipation, high bondability, and reliability. be.

In order to cope with such thickening of copper, International Publication No. 2017/213207 (Patent Document 7) describes that it is important to control the morphology of the active metal compound layer, which is the key to the bonding force in the bonding layer. ing. In Patent Documents 1 to 6, a paste-like active metal brazing material is used, but in Patent Document 7, since there is a limit to the paste-like brazing material, an alloyed bulk-like active metal brazing material is used. A method of joining to a ceramic substrate by a clad composite material is disclosed. This document describes Ag—Cu—Ti—Sn alloys as active metal brazing materials to be clad.

Japanese Unexamined Patent Publication No. 2002-137974 Japanese Unexamined Patent Publication No. 2014-90144 JP-A-2017-130686 International Publication No. 2019/022133 International Publication No. 2018/199060 JP-A-2019-64865 International Publication No. 2017/213207

However, the bulk-shaped active metal brazing material of Patent Document 7 is difficult to prepare and inferior in terms of handleability as compared with the paste-shaped brazing material, so that the productivity is low and the copper-coated substrate cannot be efficiently manufactured.

Further, as a specific thickness of the copper plate when thick copper is applied, for example, a SiC power semiconductor element needs to have a thickness of 0.5 mm or more (for example, 1 mm or 3 mm). However, in an AMC substrate that is usually bonded at a high temperature of about 900 ° C., the thicker the copper plate, the greater the thermal stress generated during cooling. Even if it could be joined, it was unreliable due to residual stress. Therefore, the present inventors have focused on joining the ceramic substrate and the copper plate at a lower temperature from the viewpoint of reducing the thermal stress at the time of joining, which may cause a load larger than the operating temperature, and ensuring the bondability. did.

As an example of bonding at a relatively low bonding temperature, in Example 6 of Patent Document 5, an oxygen-free copper plate having a thickness of 0.8 mm is bonded to a silicon nitride substrate at a bonding temperature of 725 ° C., but the bonding temperature is set to 710 ° C. In Comparative Examples 5 to 6 in which the copper plate was lowered, it was described that the copper plate was peeled off, and there was a limit in ensuring good bondability at a low temperature.

Therefore, an object of the present invention is a bonding layer (or a copper-coated substrate) that can be effectively bonded to a ceramic substrate even at a thick copper plate at a low temperature, has excellent durability and reliability (heat impact resistance), and has a good appearance. It is an object of the present invention to provide a bonding agent (bonding material, active metal brazing material or metal paste) capable of forming the bonding material, and a copper-coated substrate formed using the bonding material and a method for producing the same.

As a result of diligent studies to achieve the above-mentioned problems, the present inventors adjusted the ratio (or atomic (element) ratio) of Ag, Cu and Sn to a specific range and combined it with an active metal to obtain a thick copper plate. However, we have found that it can be effectively bonded to a ceramic substrate at a low temperature, and completed the present invention.

That is, the paste-like composition (bonding agent (bonding composition) or active metal brazing material) of the present invention is an inactive metal component (1) [or containing Sn and at least one selected from Ag and Cu. Alloy forming component (1)]; A metal paste containing an active metal component (2) containing an active metal; and an organic vehicle (3);
The composition ratio of Ag, Cu and Sn in the non-active metal component (1) is defined as (Ag, Cu, Sn) on triangular coordinates as the ratio of each atom to the total amount of Ag, Cu and Sn [unit: atm%]. When expressed, the composition ratio is (Ag, Cu, Sn) = (74,0,26), (67,12,21), (43,46,11), (23,62,15), (15). , 65,20), (0,59,41), (0,13,87), (35,13,52), and (29,0,71) [preferably (Ag, Cu). , Sn) = (74,0,26), (67,12,21), (58,25,17), (47,40,13), (43,46,11), (33,54,13) ), (23,62,15), (15,65,20), (0,59,41), (0,13,87), (35,13,52), (32,6,62) and (Regions A to D) surrounded by (29,0,71)] or the outer edge (or near) of the bonding agent.

In the present application, the "outer edge" (near the outside) of the predetermined region on the triangular coordinates is the outside of the predetermined region [the range not included in the predetermined region (inside the region and on the boundary line)] and , When the coordinates of an arbitrary point P on the boundary line that partitions (defines) the predetermined area are (Ag, Cu, Sn) = ( _PAg , P _Cu , P _Sn ), (P _Ag + P _Cu + P _Sn = 100). [Atm%]), (Ag, Cu, Sn) = (P _Ag + α, P _Cu + β, P _Sn + γ) forms a point Q (where α, β and γ satisfy all of the following equations). It may be a range (region) to be used, that is, a range or region (outer edge portion or outer peripheral portion of the predetermined region) in which the point Q may exist outside the predetermined region.

-2 ≤ α ≤ 2
-2 ≤ β ≤ 2
-2 ≤ γ ≤ 2
α + β + γ = 0

The composition ratios of Ag, Cu and Sn in the inactive metal component (1) are (Ag, Cu, Sn) = (74,0,26), (67,12,21), (43,46,11). , (23,62,15), (15,65,20), (35,13,52), and (29,0,71), preferably in the area or its outer edge (nearby); Area surrounded by (Ag, Cu, Sn) = (74,0,26), (67,12,21), (35,13,52), and (29,0,71) or its outer edge (nearby) ) Is more preferable.

In particular, the composition ratios of Ag, Cu and Sn in the inactive metal component (1) are (Ag, Cu, Sn) = (74,0,26), (67,12,21), (58,25, 17), (47,40,13), (43,46,11), (33,54,13), (23,62,15), (15,65,20), (22,46,32) , (30,25,45), (35,13,52), (32,6,62) and (29,0,71) in the area (areas A to C) or its outer edge (nearby). Preferably;
(Ag, Cu, Sn) = (74,0,26), (67,12,21), (58,25,17), (47,40,13), (35,13,52), (32) , 6,62) and (29,0,71) surrounded by regions (regions A to B) [among them, (Ag, Cu, Sn) = (74,0,26), (67,12,21) ), (58,25,17), (47,40,13), (48,32,20), (51,13,36), (35,13,52), (32,6,62) and It is more preferably in the region (regions A to B ⁺ )] surrounded by (29,0,71) or its outer edge (nearby);
(Ag, Cu, Sn) = (74,0,26), (67,12,21), (51,13,36), (35,13,52), (32,6,62) and (29) , 0, 71), more preferably in the region (region A) or its outer edge (nearby).

Further, when the alloy is formed by the composition ratio of Ag, Cu and Sn in the non-active metal component (1), the melting point (or melting temperature) of the alloy may be about 400 to 650 ° C.

The active metal may be at least one selected from Ti, Zr, Hf, and Nb. The active metal component (2) may contain a hydride of the active metal. The ratio of the active metal component (2) may be about 0.5 to 30 parts by mass with respect to 100 parts by mass of the total amount of the inactive metal component (1).

The bonding agent (metal paste) may be an active metal brazing material for forming a copper-coated substrate in which a copper plate containing copper and a ceramic substrate are bonded. The average thickness of the copper plate may be about 0.5 to 5 mm. The ceramic substrate may contain at least one selected from silicon nitride, aluminum nitride, and alumina. The copper-clad substrate may be a circuit board for a power module.

The present invention comprises copper comprising the copper plate and the ceramic substrate and a bonding layer interposed between the copper plate and the ceramic substrate and formed of a fired product (or sintered body) of the bonding agent (metal paste). Includes pasted substrate.

Further, the present invention is a laminating step of forming a laminate including the copper plate and the ceramic substrate, and a metal paste layer interposed between the copper plate and the ceramic substrate and formed of the bonding agent (metal paste). When;
It also includes a method for manufacturing a copper-coated substrate, which comprises a joining step of heating the laminated body obtained in this laminating step to form a joining layer in which the metal paste layer is fired (or sintered). The heating temperature (or joining temperature) in the joining step may be about 430 to 710 ° C.

In the present application, it is assumed that the composition ratios (Ag, Cu, Sn) of Ag, Cu, and Sn are in the "region surrounded by" a plurality of points (or a plurality of specific composition ratios) defined on the triangular coordinates. Unless otherwise specified, is not only the inside (inner region) of the polygon (concave polygon or convex polygon) formed by the plurality of points (or composition ratio), but also the sides (or the sides) constituting the polygon. It means that the composition ratio (Ag, Cu, Sn) may be located on the line segment).

Further, in the present application, the "melting point" (or "melting temperature") of the alloy means the solid phase temperature.

The bonding agent (bonding material, bonding composition, metal paste or active metal brazing material) of the present invention can effectively bond a thick copper plate to a ceramic substrate at a low temperature. In addition to exhibiting high bondability (adhesiveness or adhesion), even if thermal stress (or load due to thermal expansion difference) generated by thermal cycles such as switching operation is repeatedly applied, substrate cracking and copper plate peeling are effective. It can be suppressed and has excellent durability and reliability (heat impact resistance). In addition, the appearance of the bonding layer is also good. Although the appearance is a trade-off characteristic that is difficult to satisfy at the same time as the bondability and durability reliability, these characteristics can be satisfied in a well-balanced manner. Further, even a paste-like composition can be effectively bonded at a low temperature, so that a copper-coated substrate can be efficiently manufactured (with high productivity).

FIG. 1 is a triangular coordinate for explaining a range (regions A, B, C, D and boundary lines X, Y) of the composition ratio (Ag, Cu, Sn) of Ag, Cu, and Sn of the present invention. FIG. 2 is a schematic view for explaining a method of manufacturing a copper-clad substrate in an embodiment. FIG. 3 is triangular coordinates showing the composition ratio (Ag, Cu, Sn) of Ag, Cu, and Sn of the bonding composition (metal paste) or the bonding layer in the examples.

[Jointing agent (bonding composition or metal paste)]
The bonding agent (bonding composition or metal paste) contains an inactive metal component (1) containing a specific metal different from the active metal in a predetermined ratio; and an active metal component (2) containing an active metal; an organic vehicle. (3) and is included.

(1) Non-active metal component (metal layer forming metal component or alloy forming component)
The inactive metal component (1) includes at least one first inactive metal component selected from Ag and Cu as a metal component different from the active metal described later, and Sn as a second inactive metal component. Is contained in a predetermined ratio (composition ratio or atomic (element) ratio). These inactive metal components (1) form an alloy that is the main component of the brazing filler metal layer in the bonded layer after firing (or sintering).

The first non-active metal component preferably contains at least Ag from the viewpoint of easily improving bondability, and when Cu is contained, the proportion of Cu (composition ratio or atomic ratio) is Ag, as will be described later. It is more preferably less than, and it does not have to contain substantially Cu.

By including Sn as a second non-active metal component in the metal paste, the melting point (or melting temperature) of the formed alloy is reduced, and bonding at a lower temperature than before is possible.

Further, the inactive metal component (1) may contain another inactive metal component (third inactive metal component) different from the first and second inactive metal components, if necessary. Examples of the third non-active metal component include high melting point metals such as Ni, W, Mo, Au, Pt, and Pd, low melting point metals such as Bi, In, and Zn (or easily melted metals). These third inactive metal components may be contained alone or in combination of two or more. The ratio of these third inactive metal components is, for example, 30% by mass or less (for example, 0 to 10% by mass), preferably 5% by mass or less (for example, 0.1) with respect to the entire inactive metal component (1). ~ 3% by mass), which is substantially 0% by mass, that is, it is more preferable that the inactive metal component (1) is composed of only the first and second inactive metal components.

The form of these inactive metal components (1) is not particularly limited, but it is preferably contained in the form of particles. The metal component in the non-active metal component (1) may be contained as a single metal particle (metal particle) or may be contained as an alloyed alloy particle. The alloy particles may be alloy particles in which all the metal components of the metal components in the non-active metal component (1) are alloyed, but at least a part of the metal components may be alloyed. The preferred form of the non-active metal component (1) is a mixed particle of each metal single particle (metal particle) or a mixed particle in which a metal single particle (metal particle) and an alloy particle are combined.

Typical shapes of the particulate inactive metal component (1) (inactive metal particles such as the single metal particles and alloy particles) include, for example, a spherical shape (a true spherical shape or a substantially spherical shape) and an ellipsoidal body (an ellipsoidal sphere). Shapes, polyhedrons (polygonites, cubes, rectangular parallelepipeds, etc.), plates (flats, scales, flakes, etc.), rods or rods, fibrous, needles, irregular shapes, etc. These are usually spherical, ellipsoidal, polyhedron, and indefinite. A spherical shape is preferable because the filling density is high and the fluidity as a paste is excellent.

The central particle size (D50) of the particulate inactive metal component (1) (inactive metal particles such as the single metal particles and alloy particles) has fluidity as a paste, compactness after firing, and airtightness and bonding. From the viewpoint of improving the property (adhesion), it may be about 100 μm or less (particularly 50 μm or less), for example, 0.001 to 50 μm, preferably 0.01 to 20 μm, more preferably 0.1 to 15 μm, and further. It is preferably 0.2 to 10 μm.

In the present application, the central particle size means an average particle size (volume basis) measured by using a laser diffraction / scattering type particle size distribution measuring device.

The particulate inactive metal component (1) (inactive metal particles such as the single metal particles and alloy particles) can improve the metal content in the paste, and the denseness (bonding property) and thermal conductivity of the bonding layer can be improved. Inactive metal small particles (hereinafter referred to as "small particles") having a particle size of less than 3 μm (for example, 1 nm or more and less than 3 μm) and particles from the viewpoint of improving the handleability of the paste (adjusting the viscosity). A combination with large particles of inactive metal having a diameter of 3 to 50 μm (hereinafter referred to as “large particles”) is preferable.

The central particle size of the small particles is, for example, 0.1 to 2.5 μm, preferably 0.2 to 2 μm, more preferably 0.25 to 1.5 μm, and more preferably 0.3 to 1 μm. If the central particle size of the small particles is too small, the viscosity of the metal paste may increase and handleability may become difficult, and if it is too large, the denseness (bondability) may decrease.

The central particle size of the large particles is, for example, 3 to 30 μm, preferably 4 to 20 μm, more preferably 4.5 to 15 μm, and more preferably 5 to 10 μm. If the central particle size of the large particles is too small, the sintering shrinkage of the paste may be large, and if it is too large, the denseness (bondability) of the bonded portion may be deteriorated.

When small particles and large particles are combined as the particulate inactive metal component (1) (inactive metal particles such as the single metal particles and alloy particles), the ratio of the small particles to 100 parts by volume of the large particles is For example, it is 1 to 500 parts by volume, preferably 50 to 400 parts by volume, more preferably 70 to 300 parts by volume, and more preferably 90 to 230 parts by volume. If the proportion of small particles is too small, the denseness (bondability) of the bonded portion may be deteriorated, and if it is too large, the handleability may be deteriorated.

In the present application, the volume ratio indicates the volume ratio at 25 ° C. and under atmospheric pressure.

The particulate inactive metal component (1) (inactive metal particles such as the elemental metal particles and alloy particles) can be produced by a conventional method, for example, a wet reduction method, an electrolysis method, an atomizing method, a water atomizing method, or the like. It can be manufactured by various manufacturing methods.

(Composition ratio of inactive metal component (1))
In the non-active metal component (1), the composition ratio of Ag, Cu and Sn, that is, the ratio of each atom to the total amount (100 atm%) of Ag, Cu and Sn [unit: atm%] is adjusted to a predetermined range. ing. When each ratio (atomic ratio or element ratio) [unit: atm%] of Ag, Cu and Sn is expressed as (Ag, Cu, Sn) on the triangular coordinates, the composition ratio is (Ag, Cu, Sn) =. (74,0,26), (67,12,21), (58,25,17), (47,40,13), (43,46,11), (33,54,13), (23) , 62,15), (15,65,20), (0,59,41), (0,13,87), (35,13,52), (32,6,62) and (29,0) , 71), that is, in any of regions A, B (including B ⁺ ), C and D, or the outer edge thereof (preferably said region), as shown in FIG.

In the present application, the "region A" is (Ag, Cu, Sn) = (74,0,26), (67,12,21), (51,13,36), (35,13,52). , (32,6,62) and (29,0,71) means the composition ratio of the region (inside and on the boundary);
"Region B" includes (Ag, Cu, Sn) = (67,12,21), (58,25,17), (47,40,13), (35,13,52) and (51,13). , 36) [except on the straight line (line segment) connecting (67,12,21), (51,13,36) and (35,13,52) in this order] Means ratio;
"Region B ⁺ " means (Ag, Cu, Sn) = (67,12,21), (58,25,17), (47,40,13), (48,32,20) and (51, It means the composition ratio of the region surrounded by 13,36) [except on the straight line (line segment) connecting (67,12,21) and (51,13,36)];
"Region C" is (Ag, Cu, Sn) = (47,40,13), (43,46,11), (33,54,13), (23,62,15), (15,65). , 20), (22,46,32), (30,25,45) and (35,13,52) [however, (47,40,13) and (35,13,52). Except on the straight line (line segment) connecting the]] means the composition ratio;
"Region D" is (Ag, Cu, Sn) = (15,65,20), (0,59,41), (0,13,87), (35,13,52), (30,25). , 45) and the area enclosed by (22,46,32) [however, (15,65,20), (22,46,32), (30,25,45) and (35,13,52). Except on the straight line (line segment) connecting in this order].

The composition ratios are in regions A to C (regions A + B + C) because the bondability can be improved more effectively at low temperatures even for thick copper plates (or even if the difference in the coefficient of thermal expansion between the copper plate and the ceramic substrate is large). Also referred to) or its outer edge (nearby), more preferably regions A to B (also referred to as region A + B) or its outer edge, and even more preferably regions A to B ⁺ (also referred to as region A + B ⁺ ) or its outer edge. Especially, the region A or the outer edge thereof is preferable. That is, the bondability is improved from the region D toward the region A [or in the regions A to D, in the direction in which Ag increases and / or in the direction in which Cu decreases (left side and / or lower side in FIG. 1)]. It seems to be easier to do.

From the same viewpoint, the composition ratios are (Ag, Cu, Sn) = (74,0,26), (67,12,21), (43,46,11), (23,62,15). ), (15,65,20), (35,13,52) and (29,0,71), more preferably (Ag, Cu, Sn) = (74, It may be in the area enclosed by 0,26), (67,12,21), (35,13,52), and (29,0,71).

In the bonding composition (metal paste) of the present invention, since the composition ratios of Ag, Cu and Sn are adjusted to be within a predetermined range in this way, the melting point (or melting temperature) of the alloy forming the brazing filler metal layer is formed. ) Is reduced, and it is presumed that bonding can be performed even at a lower temperature than before, but as the present inventors initially focused on, the bonding temperature (or the melting point of the alloy) is simply lowered to perform bonding. If only the thermal stress generated by heating (firing or sintering) and cooling at the time could be reduced, the bondability could not be improved. In addition, the melting point (melting temperature) and bonding temperature (firing or sintering temperature) of the alloy are closely related not only to the bonding property but also to the durability reliability (heat impact resistance) and the appearance after bonding. It was particularly difficult to satisfy the characteristics of.

Specifically, when the melting point (melting temperature) of the alloy is lowered, the alloy can be melted at a low bonding temperature to form a bonding layer (or brazing material layer), so that thermal stress during bonding can be suppressed and the bonding property can be improved. On the other hand, the bonding temperature is too low and the active metal component (2) cannot sufficiently react with the ceramic substrate, which may reduce the bonding property or the durability reliability (heat impact resistance). However, if the bonding temperature is raised too high in order to improve the reactivity of the active metal component (2), the fluidity of the bonding layer or the brazing filler metal layer (or the inactive metal component (1)) becomes too high, so that the bonding layer is inactive. The metal component (1) flows out, causing protrusion on the ceramic substrate and crawling on the copper plate, which causes poor appearance. Such poor appearance not only has an adverse effect when plating or soldering the copper plate surface in the post-process after manufacturing the copper-coated substrate, but also deteriorates the bondability especially when it is excessively discharged. May cause. Further, such poor appearance is related to the wettability to the ceramic substrate or the copper plate and changes depending on the composition ratio of Ag, Cu and Sn, so that it is extremely difficult to satisfy the above-mentioned characteristics at the same time. In the present invention, since the composition ratios of Ag, Cu and Sn are adjusted within a predetermined range, these characteristics can be effectively satisfied.

The melting point when the alloy is formed with the composition ratios of Ag, Cu and Sn may be, for example, about 400 to 650 ° C. (for example, 450 to 630 ° C.), preferably 470 to 650 ° C. (for example, 490 to 600 ° C.). ), More preferably 500 to 650 ° C (for example, 510 to 550 ° C). If the melting point (melting temperature) of the alloy is too high, a high bonding temperature (firing or sintering temperature) is required to ensure bonding (or wettability), and the large thermal stress (load) generated during cooling causes the copper plate to have a high bonding temperature. Warpage and cracking of the ceramic substrate are likely to occur, and in particular, a thick copper plate that causes a large load may not be effectively bonded. On the other hand, if the melting point (melting temperature) of the alloy is too low, it is necessary to adjust the bonding temperature low in order to suppress the appearance and / or bonding failure due to the outflow of the bonding layer (or brazing material layer), and the active metal component (or active metal component). 2) may not sufficiently react with the ceramic substrate, resulting in deterioration of bondability and durability reliability (heat impact resistance).

The melting point when the alloy is formed with the composition ratios of Ag, Cu and Sn can be measured by a conventional method, for example, differential scanning calorimetry (DSC).

In addition, in FIG. 1, (Ag, Cu, Sn) = (74,0,26), (67,12,21), (58,25,17), (47,40,13), (43,46). , 11), (33,54,13), (23,62,15), (15,65,20) and (0,59,41). That is, the boundary line between the regions A to D and the region located outside the regions A to D and having a low Sn ratio (the region including Reference Examples 1 to 5 and Reference Examples 9 to 10 described later). Let X;
Boundary composed of line segments connecting (Ag, Cu, Sn) = (0,13,87), (35,13,52), (32,6,62) and (29,0,71) in this order. The boundary line between the lines, that is, the regions A to D and the regions located outside the regions A to D and having a high Sn ratio (regions including Reference Examples 6 to 8 described later) was defined as Y.

A composition ratio of a solid-liquid boundary (or melting point) of about 600 to 650 ° C. exists near the boundary line X, and a solid-liquid boundary of about 400 ° C. exists near the boundary line Y, and the boundary line X and the boundary line Y exist. In the region between and (the melting point of the alloy is about 400 to 650 ° C.), it seems that a thick copper plate can be bonded at a low temperature of about 700 ° C. or lower.

Therefore, the composition ratio of Ag, Cu, and Sn may be within the region (inside and on the boundary line) as described above, but within a range that does not impair the effect of the present invention (within a range that can ensure bondability). ), The outer edge of the region (near the outside, for example, the outer edge (near) of the boundaries X and Y).

As the outer edge of the region (near the outside of the region), each component is, for example, 2 atm% (for example, 1.5 atm%) from the boundary line that divides the region to the outside (toward the vertical direction of the boundary line). The region may be preferably in the range of about 1 atm% (for example, 0.5 atm%), more preferably about 0.3 atm% (for example, 0.1 atm%). For example, the outer edge (nearby) of a region is (Ag, Cu, Cu) when the coordinates of an arbitrary point P on the boundary line that divides the region are (Ag, Cu, Sn) = (P _Ag , P _Cu , P _Sn ). , Sn) = (P _Ag + α, P _Cu + β, P _Sn + γ) may be a region formed by a point Q (where α, β and γ satisfy all of the following equations).

-2 ≤ α ≤ 2
-2 ≤ β ≤ 2
-2 ≤ γ ≤ 2
α + β + γ = 0

Preferred α is −1.5 ≦ α ≦ 1.5 (for example, -1 ≦ α ≦ 1), and more preferably −0.5 ≦ α ≦ 0.5 (for example, −0.3 ≦ α ≦ 0. 3) In particular, −0.1 ≦ α ≦ 0.1 may be used. The preferred range of β and the range of γ are also the same as the preferred range of α, respectively. The ranges of α, β and γ may be the same or different.

Further, the composition ratio (atomic ratio) of Ag may be within the above range (region) or its outer edge (nearby), but with respect to the entire inactive metal component (1) (particularly, the total amount of Ag, Cu and Sn). It may be selected from about 0 to 76 atm%, for example, 0 to 74 atm% (for example, 15 to 74 atm%), preferably 29 to 74 atm% (for example, 35 to 74 atm%), and more preferably 44 to 74 atm% (for example). 60-74 atm%). The composition ratio (atomic ratio) of Ag is, for example, 0 to 72% by mass (for example, 20 to 72% by mass) with respect to the entire non-active metal component (1) (particularly, the total amount of Ag, Cu and Sn). It is preferably 27 to 72% by mass (for example, 35 to 72% by mass), and more preferably 44 to 72% by mass (for example, 58 to 72% by mass). If the composition ratio (atomic ratio) of Ag is too small, the bondability may deteriorate.

The composition ratio (atomic ratio) of Cu may be within the above range or at the outer edge (near) thereof, but is, for example, 0 to 0 with respect to the entire inactive metal component (1) (particularly, the total amount of Ag, Cu and Sn). It is 65 atm% (for example, 0 to 53 atm%), preferably 0 to 46 atm% (for example, 0 to 32 atm%), more preferably 0 to 19 atm% (for example, 0 to 13 atm%), and particularly preferably 0 to 12 atm%. The composition ratio (atomic ratio) of Cu is, for example, 0 to 51% by mass (for example, 0 to 39% by mass) with respect to the entire inactive metal component (1) (particularly, the total amount of Ag, Cu and Sn). It is preferably 0 to 33% by mass (for example, 0 to 21% by mass), more preferably 0 to 12% by mass (for example, 0 to 7.8% by mass), particularly preferably 0 to 7% by mass, and is substantially Cu. It does not have to contain. If the composition ratio (atomic ratio) of Cu is too large, the bondability and durability reliability may deteriorate.

The composition ratio (atomic ratio) of Sn may be within the above range or at the outer edge (near) thereof, but is 10 to 89 atm with respect to the entire inactive metal component (1) (particularly, the total amount of Ag, Cu and Sn). It may be selected from about%, for example, 11 to 87 atm% (for example, 15 to 71 atm%), preferably 20 to 52 atm% (for example, 21 to 44 atm%), and more preferably 25 to 40 atm%.

The composition ratio (atomic ratio) of Sn is, for example, 15 to 92.5% by mass (for example, 22 to 73% by mass) with respect to the entire inactive metal component (1) (particularly, the total amount of Ag, Cu and Sn). ), It is preferably 24 to 57.2% by mass (for example, 25 to 49% by mass), and more preferably 28 to 42% by mass. If the composition ratio (atomic ratio) of Sn is too small, the melting point (melting temperature) of the alloy cannot be sufficiently reduced and a high bonding temperature is required. It may decrease. If the composition ratio (atomic ratio) of Sn is too large, the melting point (melting temperature) of the alloy is too low (the fluidity becomes too high at the time of bonding), and the bonding layer (wax layer) flows out excessively, resulting in an appearance. If the bonding temperature is lowered in order to suppress the outflow of the bonding layer, the active metal component (2) cannot sufficiently react, and the bonding property and durability reliability are reduced. There is a risk of

(2) Active metal component Examples of the active metal contained in the active metal component include Ti, Zr, Hf, Nb and the like. These active metals may be contained alone or in combination of two or more. Of these active metals, at least one selected from the group consisting of Ti, Zr and Nb because it has excellent activity in the bonding (firing or sintering) process and can improve the bonding property between the ceramic substrate and the copper plate. Is preferred, Ti and / or Zr is even more preferred, and Ti is particularly preferred.

The active metal component (2) may contain an active metal and may be contained as a simple substance of the active metal and / or a compound containing the active metal, but the active metal is excellent in activity in the joining step. It is preferably a compound containing.

The compound containing an active metal is not particularly limited, and for example, the activity of an active metal hydride such as titanium hydride (TiH _{2), zirconium hydride (ZrH 2 )} , niobium hydride (NbH), and titanium borohydride. Examples include metal boroides. The compounds containing these active metals may be contained alone or in combination of two or more. Of these, hydride is preferable from the viewpoint of excellent activity in the joining step, and titanium hydride (TiH ₂ ) is particularly preferable.

The form of the active metal component (2) is not particularly limited, but it is preferably contained as a particulate form, that is, as an active metal-containing particle containing an active metal. As such active metal-containing particles, titanium hydride particles and / or zirconium hydride particles are preferable, and titanium hydride particles are more preferable.

The shape of the active metal-containing particles can be selected from the shapes exemplified as the shape of the particulate inactive metal component (1), including preferred embodiments.

The central particle size (D50) of the active metal-containing particles can be selected from the range of about 0.1 to 100 μm, and from the viewpoint of handleability of the metal paste, for example, 0.2 to 50 μm, preferably 0.5 to 20 μm. More preferably, it is 1 to 10 μm.

The ratio of the active metal component (2) is, for example, about 0.1 to 50 parts by mass (for example, 0.3 to 40 parts by mass), specifically, with respect to 100 parts by mass of the total amount of the inactive metal component (1). May be selected from the range of about 0.5 to 30 parts by mass (for example, 1 to 20 parts by mass, preferably 2 to 15 parts by mass, more preferably 3 to 10 parts by mass), and preferably 1.5 to 10 parts. It is by mass (for example, 2 to 5 parts by mass), more preferably 2 to 4 parts by mass. If the ratio of the active metal component (2) is too small, the bondability, especially the bondability between the bond layer (active metal compound layer) and the ceramic substrate may not be sufficiently improved, and conversely, if it is too large, the thermal conductivity (Heat dissipation) and sinterability may decrease.

(3) The organic vehicle bonding composition (metal paste) is made into an organic vehicle in addition to the inactive metal component (1) and the active metal component (2) in order to form a paste (in a fluid state). Further contains (first organic vehicle).

The organic vehicle may be a conventional organic vehicle used as an organic vehicle for a metal paste containing metal particles, for example, an organic binder and / or an organic solvent. The organic vehicle may be either an organic binder or an organic solvent, but is usually a combination of the organic binder and the organic solvent (dissolution or mixture of the organic binder by the organic solvent).

The organic binder is not particularly limited, and is, for example, a thermoplastic resin (olefin resin, vinyl resin, acrylic resin, styrene resin, polyether resin, polyester resin, polyamide resin, cellulose derivative, etc.). Examples thereof include thermosetting resins (thermosetting acrylic resins, epoxy resins, phenol resins, unsaturated polyester resins, polyurethane resins, etc.). These organic binders may be contained alone or in combination of two or more. Among these organic binders, resins that are easily burned out in the bonding process (baking or sintering process) and have a low ash content, such as acrylic resins (polymethylmethacrylate, polybutylmethacrylate, etc.), cellulose derivatives (nitrocellulose, etc.) Ethyl cellulose, butyl cellulose, cellulose acetate, etc.), polyether resins (polyoxymethylene, etc.), rubbers (polybutadiene, polyisoprene, etc.), etc. are preferable. Poly (meth) acrylic acid C _1-10 alkyl esters such as butyl poly (meth) acrylate (particularly, polyacrylic acid C _1-6 alkyl esters such as butyl polyacrylate) are preferred.

The organic solvent is not particularly limited as long as it is an organic compound that imparts appropriate viscosity to the paste and can be easily volatilized by a drying treatment after the paste is applied to a ceramic substrate and / or a copper plate, and has a high boiling point. It may be a solvent. Examples of such organic solvents include aromatic hydrocarbons (paraxylene, etc.), esters (ethyl lactate, etc.), ketones (isophorone, etc.), amides (dimethylformamide, etc.), and aliphatic alcohols (octanol, decanol). , Diacetone alcohol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates (ethyl cellosolve acetate, butyl cellosolve acetate, etc.), carbitols (carbitol, methyl carbitol, ethyl carbitol, etc.), carbitol Acetates (ethyl carbitol acetate, butyl carbitol acetate), aliphatic polyhydric alcohols (ethylene glycol, diethylene glycol, dipropylene glycol, butanediol, triethylene glycol, glycerin, etc.), alicyclic alcohols [eg, cyclo Cycloalkanols such as hexanol; terpine alcohols such as terpineol and dihydroterpineol (monoterpene alcohol, etc.)], aromatic alcohols (metacresol, etc.), aromatic carboxylic acid esters (dibutylphthalate, dioctylphthalate, etc.), Examples thereof include nitrogen-containing heterocyclic compounds (dimethylimidazole, dimethylimidazolidinone, etc.). These organic solvents may be contained alone or in combination of two or more. Among these organic solvents, carbitols such as carbitol and alicyclic alcohols such as terpineol are preferable, and alicyclic alcohols such as terpineol are more preferable from the viewpoint of the fluidity of the paste.

When the organic binder and the organic solvent are combined, the ratio of the organic binder is, for example, 1 to 200 parts by mass, preferably 10 to 100 parts by mass, and more preferably about 30 to 60 parts by mass with respect to 100 parts by mass of the organic solvent. It is 5 to 80% by mass, preferably 10 to 50% by mass, and more preferably 20 to 40% by mass with respect to the entire organic vehicle.

The ratio of the organic vehicle is, for example, 1 to 300 parts by mass (for example, 1 to 50 parts by mass), preferably 5 to 30 parts by mass (for example, 10 to 15 parts by mass) with respect to 100 parts by mass of the total amount of the inactive metal component (1). Department). If the proportion of the organic vehicle is too small, the handleability may be deteriorated, and if it is too large, voids are likely to be formed in the bonding layer after firing, and the denseness and airtightness may be deteriorated. If voids are formed near the interface with the insulating substrate (ceramic substrate), the active metal component (2) may not sufficiently react with the substrate, and the bondability (adhesion) may deteriorate.

[Copper-pasted board (copper-pasted circuit board)]
The bonding composition (metal paste) of the present invention can be effectively used as an active metal brazing material for forming a copper-coated substrate in which a copper plate containing copper and an insulating substrate (ceramic substrate) are bonded. That is, the copper-coated substrate is interposed between the copper plate, the insulating substrate (ceramic substrate), and the fired product (or sintering) of the active metal brazing material (bonding composition (metal paste)). It is an AMC substrate having a bonding layer formed of (article). In particular, by using the bonding composition (metal paste) of the present invention, it is possible to increase the thickness of the copper plate to make it thicker to improve heat dissipation. Therefore, the copper-coated substrate is used for a power module. It can be suitably used as a circuit board.

The bonding layer formed of the fired product of the active metal brazing material (bonding composition (metal paste)) is formed in at least a part of the bonding surface between the copper plate and the insulating substrate (ceramic substrate). It suffices if it is formed, and it is preferable that it is formed on the entire surface of the joint surface. Further, as described above, the bonding layer is formed by a two-layer structure consisting of a brazing material layer located on the copper plate side and an active metal compound layer located on the insulating substrate (ceramic substrate) side. The brazing filler metal layer contains an alloy in which the inactive metal component (1) is alloyed as a main component (for example, in a proportion of 50% by mass or more, preferably 90% by mass or more with respect to the entire brazing filler metal layer). You may. The active metal compound layer is mainly composed of an active metal compound formed by the reaction of the active metal component (2) with atoms such as N, O, and Si at the bonding interface with the insulating substrate (ceramic substrate). It may be contained (for example, in a proportion of 50% by mass or more, preferably 90% by mass or more with respect to the entire active metal compound layer).

The average thickness of the bonded layer (total thickness of the brazing material layer and the active metal compound layer) after firing may be, for example, about 5 to 30 μm, preferably 10 to 20 μm. If the average thickness is too thin, the bondability may decrease, and if it is too thick, the durability reliability may decrease.

(Copper plate)
The copper plate for forming the copper-coated substrate may contain at least copper, and examples thereof include copper and copper alloys. Examples of copper include oxygen-free copper and pure copper such as tough pitch copper. Examples of the copper alloy include Cu-W alloy, Cu-Mo alloy, Cu-Fe-P alloy and the like. Further, Cu and a clad material which is a composite material obtained by rolling dissimilar metals such as W and Mo into one plate may be used. Examples of the clad material include clad materials such as Cu—Mo—Cu and Cu—W—Cu in which a Cu layer is pressure-bonded to a joint surface. The proportion of copper may be, for example, about 1% by mass or more (for example, 5 to 100% by mass) or 10% by mass or more (for example, 20 to 100% by mass) with respect to the entire metal component in the copper plate. It may be preferably about 50% by mass or more (for example, 70 to 100% by mass), and more preferably about 80% by mass or more (for example, 90 to 100% by mass). These copper plates can be used alone or in combination of two or more. Of these copper plates, oxygen-free copper is preferable from the viewpoint of bondability and the like.

The copper plate may be a copper circuit (copper plate or copper circuit plate for circuit) for connecting to the semiconductor element and / or a copper heat dissipation plate (copper plate for heat dissipation) for dissipating heat generated by the semiconductor element. For example, in a copper-coated substrate, a copper circuit may be bonded to one surface of an insulating substrate (ceramic substrate) via a bonding layer, and a copper heat sink may be bonded to the other surface via a bonding layer.

The average thickness of the copper plate may be appropriately selected depending on the intended use. For example, for a power module (for a power module having a large output), the average thickness may be about 0.1 mm or more and less than 0.5 mm, as described above. By using the bonding composition (metal paste) of the present invention, the copper plate can be effectively bonded with high bonding properties even if it is made thick copper, so that the average thickness of the copper plate is, for example, 0.1 to 5 mm (for example, 0.1). It may be selected from a range of about 3 mm), preferably 0.5 mm or more (for example, 0.5 to 4 mm), more preferably 1 mm or more (for example, 1.5 to 3.5 mm), and particularly 2 mm or more (for example, 2). It is 5.5 to 3.5 mm, preferably 2.7 to 3.3 mm).

(Insulating substrate (ceramic substrate))
The substrate (insulating substrate) for forming the copper-clad substrate is required to have heat resistance because it undergoes a bonding (firing or sintering) step, and may be an organic material such as engineering plastic, but is usually used. It is a substrate made of an inorganic material (inorganic material), and is preferably a ceramic substrate on which the active metal can react.

Inorganic materials include, for example, ceramics {metal oxides (alumina or aluminum oxide (including corundum such as sapphire), zirconia or zirconate oxide, ferrite or iron oxide, titania or titanium oxide, zinc oxide, niobium oxide, verilia or oxidation. Berylium, etc.), Silicon oxide (quartz, silicon dioxide, etc.), metal nitride (aluminum nitride, titanium nitride, etc.), silicon nitride, boron nitride, carbon nitride, metal carbide (titanium carbide, tungsten carbide, etc.), silicon carbide, carbonized Boron, metal borides (titanium borate, zirconate titanate, etc.), metal compound oxides [Murite, metal titanate salts (barium titanate, strontium titanate, lead titanate, niobium titanate, calcium titanate, titanic acid) Magnesium, etc.), Zirconate metal salt (barium zirconate, calcium zirconate, lead zirconate, etc.)], etc.}, Glasses (soda glass, borosilicate glass, crown glass, barium-containing glass, strontium-containing glass, boron-containing Examples thereof include glass, low-alkali glass, non-alkali glass, crystallized transparent glass, silica glass, quartz glass, heat-resistant glass, etc.) and silicon (semiconductor silicon, etc.). The inorganic material may be a composite material of these inorganic materials and a metal (for example, enamel).

The insulating substrate may be, for example, a heat-resistant substrate such as a ceramic substrate, a glass substrate, a silicon substrate, or a brazing substrate. Among these heat-resistant substrates, an alumina substrate, a sapphire substrate, an aluminum nitride substrate, or a nitride substrate may be used. Ceramic substrates such as silicon substrates and silicon carbide substrates are preferable, alumina substrates, aluminum nitride substrates, and silicon nitride substrates are more preferable, and in terms of good appearance and excellent durability and reliability, alumina substrates, aluminum nitride substrates, and silicon nitride are preferred. A silicon substrate is more preferable, and a silicon nitride substrate is particularly preferable in terms of excellent bondability.

The surface of the insulating substrate (ceramic substrate) is subjected to oxidation treatment [surface oxidation treatment, for example, discharge treatment (corona discharge treatment, glow discharge treatment, high temperature oxidation treatment, etc.), acid treatment (chromic acid treatment, etc.), ultraviolet irradiation treatment, etc. , Flame treatment, etc.], surface unevenness treatment (solvent treatment, sandblast treatment, etc.) and other surface treatments may be applied.

The average thickness of the insulating substrate (ceramic substrate) may be appropriately selected depending on the intended use, and is, for example, 0.01 to 10 mm (for example, 0.05 to 5 mm), preferably 0.1 to 1 mm, and more preferably 0. It is 2 to 0.8 mm.

The thermal conductivity of the insulating substrate (ceramic substrate) at 25 ° C. may be appropriately selected depending on the intended use, for example, 1 to 500 W / (m · K) (for example, 10 to 400 W / (m · K)). It is preferably 15 to 300 W / (m · K), more preferably 20 to 200 W / (m · K).

In the present application, the thermal conductivity can be measured according to a conventional method, for example, JIS R 1611.

(Characteristics of copper-coated substrate)
As described above, the copper-coated substrate of the present invention can be effectively bonded even if it is a thick copper plate, and the protrusion on the ceramic substrate and the creeping up on the copper plate are suppressed, and the appearance is good. Specifically, in the copper-coated substrate, there is no protrusion and / or crawling at a distance of 0.5 mm or more from the edge (side surface) of the copper plate, and preferably no protrusion and / or crawling is observed. Since the copper-coated substrate has a good appearance as described above, it can be used for post-treatment (post-process) such as plating and soldering without adversely affecting it.

Further, since the copper-coated substrate of the present invention is excellent not only in high bondability but also in durability reliability (heat impact resistance), the substrate is peeled off or cracked even if thermal shock due to rapid heating / quenching is repeatedly applied. Such problems can be effectively suppressed. For example, a low temperature range (for example, -55 ° C. to -35 ° C., preferably about -50 ° C. to -40 ° C.) and a high temperature range (for example, 140 to 160 ° C., preferably about 145 to 155 ° C.) are each for about 30 minutes. When this operation is repeated with the operation of holding and rapidly heating / quenching as one cycle, for example, 1000 cycles or more (for example, 1000 to 10000 cycles), preferably 2000 cycles or more (for example, 2000 to 8000 cycles), more preferably. Even if it is repeated for 3000 cycles or more (for example, 3000 to 5000 cycles), defects such as peeling and cracking of the substrate can be effectively suppressed.

[Manufacturing method of copper-pasted board (copper-pasted circuit board)]
In the method for manufacturing a copper-coated substrate of the present invention, a copper plate and an insulating substrate (ceramic substrate) are bonded to a metal paste layer (bonding composition layer or bonding) formed of the bonding agent (bonding composition or metal paste). A laminating step of forming a laminated body (copper-pasted substrate precursor or preformed body) laminated via a layer precursor layer); the metal paste layer is formed by heating the laminated body obtained in this laminating step. It includes a joining step of forming a fired joining layer.

(Laminating process)
In the laminating step, the method for forming the metal paste layer (bonding composition layer or bonding layer precursor layer) interposed between the copper plate and the insulating substrate (ceramic substrate) is not particularly limited, but the copper plate and / or the insulating property is not particularly limited. It is preferable to apply the bonding agent (bonding composition or metal paste) to the substrate (ceramic substrate) to form the substrate (ceramic substrate). The coating method is not particularly limited, but a screen printing method is preferable.

The metal paste layer (bonding composition layer or bonding layer precursor layer) may be formed in at least a part of the bonding surface between the copper plate and the insulating substrate (ceramic substrate), and the entire surface of the bonding surface may be formed. It is preferably formed in.

In the laminating step, the metal paste layer (bonding composition layer or bonding layer precursor layer) may be subjected to a drying treatment before laminating the copper plate and the insulating substrate (ceramic substrate). The drying treatment may be natural drying, but it is preferably heated and dried. The heating temperature may be selected depending on the type of the organic vehicle (or organic solvent), and is, for example, 50 to 200 ° C, preferably 80 to 180 ° C, and more preferably 100 to 150 ° C. The heating time is, for example, 1 minute to 3 hours, preferably 5 minutes to 2 hours, and more preferably 10 minutes to 1 hour.

The average thickness of the metal paste layer (or the dried film) after drying is preferably 5 to 50 μm, more preferably 10 to 30 μm. If the average thickness is too thin, the bondability may decrease, and if it is too thick, the durability reliability may decrease.

In the laminating step, a copper plate may be laminated (bonded) to at least one surface of the insulating substrate (ceramic substrate) via a metal paste layer, but when laminated (bonded) to only one surface, heat is generated after firing. Since the difference in stress tends to cause warpage of the copper plate and / or cracking of the insulating substrate (ceramic substrate), it is recommended to laminate the copper plate on both sides of the insulating substrate (ceramic substrate) via the metal paste layer. preferable. Therefore, as described above, a copper circuit board may be laminated (bonded) on one surface of the insulating substrate (ceramic substrate), and a copper heat sink may be laminated (bonded) on the other surface.

(Joining process)
In the joining step, the laminated body (copper-coated substrate precursor or preformed body) obtained in the laminating step is heated (baked or sintered), and the metal paste layer is fired (or sintered). To form. The joining (firing) step may be performed using a batch furnace or a belt transport type tunnel furnace.

The heating temperature (bonding temperature, firing (or sintering) temperature) in the bonding step is the composition ratio of the inactive metal component (1) in the bonding composition (metal paste) (or the composition ratio of the inactive metal component). It depends on the melting point (melting temperature) of the alloy when (1) is alloyed, and since it does not melt at a temperature lower than the melting point of the alloy, it cannot be joined with high bondability. Therefore, the joining temperature is set to a temperature higher than the melting point of the alloy. As a typical joining temperature (set temperature or peak temperature), for example, a temperature 30 to 150 ° C. higher (for example, 35 to 120 ° C. higher), preferably 40 to 110 ° C. higher (for example) with respect to the melting point of the alloy. The temperature is 45 to 105 ° C. higher), and it is more preferable to set the temperature to be about 50 to 100 ° C. higher (for example, 60 to 90 ° C. higher temperature). The melting point (melting temperature) of the alloy includes the melting point when the alloy is formed with the composition ratios of Ag, Cu and Sn described in the above section (composition ratio of the inactive metal component (1)) and a preferable embodiment. It may be similar. As a more specific joining temperature (set temperature), for example, 430 to 710 ° C., preferably 450 to 700 ° C. (for example, 500 to 700 ° C., preferably 550 to 700 ° C.), still more preferably 600 to 700 ° C. (for example, 650 ° C.). ~ 700 ° C.). If the joining temperature is too high, the copper plate is likely to warp or crack the ceramic substrate due to the large thermal stress (load) generated during cooling, and in particular, a thick copper plate that causes a large load may not be effectively joined, and the joining layer (joint layer). The fluidity of the brazing filler metal layer or the alloy formed of the non-active metal component (1) becomes too high, causing protrusion on the ceramic substrate and creeping up on the copper plate, resulting in appearance and / or poor bonding. There is a risk. On the other hand, if the bonding temperature is too low, the active metal component (2) in the bonding composition may not sufficiently react with the ceramic substrate, resulting in deterioration of bonding properties and durability reliability (heat impact resistance). There is.

The joining step may be performed in any atmosphere (firing atmosphere) in an inert gas atmosphere such as nitrogen gas or in a vacuum atmosphere. From the viewpoint of productivity (or cost reduction), it is preferable to carry out in an inert gas atmosphere. In particular, in the present invention, the copper plate and the insulating substrate (ceramic substrate) can be effectively bonded even in a nitrogen gas atmosphere, so that the nitrogen gas atmosphere is particularly preferable.

In the joining step, in order to prevent the copper plate from warping, firing may be performed while applying a load to the joining surface. The method of applying the load is not particularly limited, and a weight may be placed on the upper surface of the copper-clad substrate (or copper plate) to apply the load. The load (or pressure) on the joint surface is, for example, 0.1 to 10 gf / mm ² , preferably 0.5 to 5 gf / mm ² . When a load is applied, a ceramic substrate (a ceramic substrate different from the insulating substrate for forming the copper-clad substrate) having a size larger than the contact surface of the weight is sandwiched between the copper plate and the weight. It is preferable to bake.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. Details of the materials used, preparation method, evaluation method, etc. are shown below.

[Material used]
(Nonactive metal component)
Ag (silver) particles: Silver particles with a central particle size of 0.5 μm, melting point 962 ° C.
Cu (copper) particles: Copper particles with a central particle size of 2.0 μm, melting point 1085 ° C.
AgCu (silver-copper) alloy particles: center particle size 5.0 μm, 72Ag-28Cu alloy particles, melting point 780 ° C.
Sn (tin) particles: tin particles with a central particle size of 5.0 μm and a melting point of 232 ° C.
(Active metal component)
Titanium hydride: Titanium hydride particles with a central particle size of 6.0 μm Zirconium hydride: Zirconium hydride particles with a central particle size of 5.0 μm (organic vehicle)
A mixture (copper plate (or copper alloy plate)) in which acrylic resin (butyl polyacrylate), which is an organic binder, and telepineol, which is an organic solvent, are mixed in a mass ratio of organic binder: organic solvent = 4: 9.
Copper plate (0.5 mm): 30 mm x 30 mm x 0.5 mm, C1020 material (oxygen-free copper)
Copper plate (1 mm): 30 mm x 30 mm x 1.0 mm, C1020 material (oxygen-free copper)
Copper plate (2 mm): 30 mm x 30 mm x 2.0 mm, C1020 material (oxygen-free copper)
Copper plate (3 mm): 30 mm x 30 mm x 3.0 mm, C1020 material (oxygen-free copper)
Cu-W alloy plate (2 mm): 30 mm x 30 mm x 2.0 mm, copper-tungsten alloy plate, composition 80W-20Cu
Cu-W alloy plate (3 mm): 30 mm x 30 mm x 3.0 mm, copper-tungsten alloy plate, composition 80W-20Cu
(Ceramics substrate)
Silicon Nitride (Si ₃ N ₄ ) Substrate: 50.8 mm x 50.8 mm x 0.3 mm, thermal conductivity 90 W / (m · K)
Alumina (Al ₂ O ₃ ) substrate: 76.2 mm × 76.2 mm × 0.635 mm, purity 96%, thermal conductivity 24 W / (m · K)
Aluminum nitride (AlN) substrate: 76.2 mm × 76.2 mm × 0.635 mm, thermal conductivity 170 W / (m · K).

[Preparation of bonding composition (metal paste)]
Each raw material was weighed according to the composition shown in Tables 1 to 5 or 12, mixed with a mixer, and then uniformly kneaded with three rolls to prepare a bonding composition (metal paste).

[Manufacturing of copper-coated substrate]
As shown in FIGS. 2A to 2E, copper-coated substrates were produced. That is, (a) using the bonding composition (metal paste) shown in Tables 1 to 5 or 12 on both sides of the ceramic substrate 2, a 30 mm × 30 mm square pattern is applied by screen printing and printed. Films (metal paste layers) 3a and 3b were formed. The average film thickness of the printed films 3a and 3b before drying was about 20 μm, respectively, and the average film thickness after drying the printed films 3a and 3b for 10 minutes with a blower dryer at 120 ° C. was about 17 μm, respectively. (C) After drying, two 30 mm × 30 mm square copper plates 4a and 4b are laminated together with the printed films (metal paste layers) 3a and 3b on both sides (upper surface and lower surface) of the ceramic substrate 2, respectively. A precursor (laminated body) 1 of a copper-pasted substrate was formed. (D) Then, in a state where both sides of the precursor (laminated body) 1 of the copper-clad substrate are sandwiched between heat-resistant plates (ceramic plates) 5a and 5b and a load is applied from the upper side by a weight 6 of 1 kg, the inside of the belt-type continuous firing furnace. In a nitrogen atmosphere, firing is performed for 15 minutes (peak holding time) at a predetermined peak temperature (firing temperature or bonding temperature), and (e) the copper-clad substrate 10 (bonding layers 13a on both sides of the ceramic substrate 2). A substrate on which copper plates 4a and 4b were laminated via 13b) was produced. The average film thickness of the bonded layers 13a and 13b after firing was about 12 μm, respectively.

[Evaluation of bondability]
For each bonding composition (metal paste), the bonding property against thick copper was verified, and superiority or inferiority judgment (ranking) was performed. Specifically, the thickness of the copper plate was increased in the order of 0.5 mm, 1 mm, and 3 mm (thick copper), and it was verified to what thickness the copper plate could be joined. If it could not be joined, the bondability to a copper plate with a thickness of 2 mm was also verified. As the copper plate, oxygen-free copper was used in the examples other than Example 37. Further, since the melting point differs depending on the composition of the brazing material component or the non-active metal component (Ag (silver), Cu (copper), Sn (tin)) in each bonding composition and the alloying state thereof, the firing setting is set. The temperature (peak temperature, firing temperature or joining temperature) was set at least at three levels of 450 ° C, 600 ° C and 700 ° C (and also at 500 ° C, 550 ° C or 650 ° C depending on the composition), and the temperature at which joining was possible was verified. did.

Regarding the bondability, in the copper-coated substrate bonded (manufactured) in the above verification, the ceramic substrate was not cracked or warped, and a razor was inserted in the bonding layer between the copper plate and the ceramic substrate. However, when the copper plate was not easily peeled off from the ceramic substrate, it was judged as "joined (passed)" and indicated by "○". On the other hand, if the ceramic substrate is cracked, the copper plate is warped, or if a razor is inserted into the joint layer and the material is easily peeled off, it is judged as "unable to join (failure)" and is indicated by "x". .. In addition, among the bonding compositions (metal pastes) that have been bonded (passed), the bonding composition that can bond the thickest 3 mm copper plate is a rank, and the bonding composition that can bond the 2 mm copper plate is The bonding composition capable of joining b rank and 1 mm copper plate was ranked as c rank, and the bonding composition capable of joining 0.5 mm copper plate was ranked as d rank.

(criterion)
a rank: A copper plate with a thickness of 3 mm can be joined (passed)
Rank b: A copper plate with a thickness of 2 mm can be joined (passed)
c rank: A copper plate with a thickness of 1 mm can be joined (passed)
d rank: A copper plate with a thickness of 0.5 mm can be joined (passed)
e rank: At any joining temperature, a copper plate with a thickness of 0.5 mm cannot be joined, the substrate cracks, or the copper plate warps (failure).

[Appearance evaluation]
Among the copper-coated substrates produced in the bondability evaluation, the appearance of the copper-coated substrates that passed (a, b, c or d rank) was evaluated. Appearance evaluation was performed on a copper-coated substrate using the thickest copper plate that could be bonded at each bonding composition and its firing temperature. In the appearance evaluation, it was observed with a loupe (15 times) whether the bonding layer crawls up to the copper plate or protrudes from the ceramic substrate. The results were judged according to the following criteria, and rank b or higher was regarded as acceptable.

(criterion)
a rank: No crawling or protrusion is seen (pass)
Rank b: Crawling up or protruding from the edge (side surface) of the copper plate is less than 0.5 mm (passed)
Rank c: Crawling up or protruding at a distance of 0.5 mm or more from the edge (side surface) of the copper plate is seen (failure).

[Durability reliability evaluation (heat impact test)]
Among the copper-clad substrates produced in the bondability evaluation, the copper-clad substrate that passed the bondability evaluation and the appearance evaluation was subjected to a thermal shock test. The operation of holding for 30 minutes each in the low temperature region (-45 ° C.) and the high temperature region (150 ° C.) and heating and cooling was repeated as one cycle, and defects such as peeling of the copper plate and cracking of the ceramic substrate were confirmed. Initial confirmation was performed after 1000 cycles, and if there were no problems, it continued until 2000 cycles. If there were no problems after 2000 cycles, the procedure was continued up to 3000 cycles. The result was judged according to the following criteria, and c rank or higher was regarded as acceptable.

(criterion)
a rank: No defects (peeling of copper plate, cracking of ceramic substrate) after 3000 cycles (pass)
Rank b: No problem after 2000 cycles (passed)
c rank: No problem after 1000 cycles (pass)
d rank: A defect was confirmed after 1000 cycles (failed).

[Comprehensive judgment]
As a comprehensive judgment of bondability evaluation, appearance evaluation, and durability reliability evaluation, superiority or inferiority judgment (ranking) was performed from the viewpoint of bondability to thick copper based on the following criteria. The bonding composition capable of bonding the thickest 3 mm copper plate was regarded as the best A rank, and the D rank or higher was regarded as acceptable.

(criterion)
A rank: The bondability evaluation is a rank, and both the appearance evaluation and the durability reliability evaluation are pass levels (appearance evaluation is a or b rank, durability reliability evaluation is a, b or c rank).
B rank: Bondability evaluation is b rank, both appearance evaluation and durability reliability evaluation are pass level C rank: Joinability evaluation is c rank, appearance evaluation and durability reliability evaluation are both pass level D rank: Joining The sex evaluation is d rank, and the appearance evaluation and the durability reliability evaluation are all pass levels. E rank: Any one of the bondability evaluation, the appearance evaluation and the durability reliability evaluation is a fail level (the appearance evaluation is c rank). , Or the durability reliability evaluation is d rank).

[Example 1] (two components, Ag and Sn)
Using a silicon nitride substrate as a ceramic substrate and a metal paste (composition 1) having a composition (region A) of (Ag, Cu, Sn) = (74, 0, 26) as a bonding composition, a copper-coated substrate was formed. It was prepared and evaluated in various ways. When the firing temperature is 700 ° C., any copper plate (oxygen-free copper) of 0.5 mm, 1 mm, and 3 mm can be bonded, and good results are obtained in the bondability evaluation, appearance evaluation, and durability reliability evaluation. It became A rank.

[Example 2] (two components, Ag and Sn)
Example 1 except that the metal paste (composition 2) having the composition (region A) of (Ag, Cu, Sn) = (70, 0, 30) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., any copper plate of 0.5 mm, 1 mm, or 3 mm could be joined, and good results were obtained in the bondability evaluation, appearance evaluation, and durability reliability evaluation, and the rank was A. ..

[Example 3] (two components, Ag and Sn)
Example 1 except that the metal paste (composition 3) having the composition (region A) of (Ag, Cu, Sn) = (60, 0, 40) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 600 ° C, any copper plate of 0.5 mm, 1 mm, or 3 mm could be joined, and good results were obtained in the bondability evaluation, appearance evaluation, and durability reliability evaluation, and the result was A rank. ..

[Example 4 (4a, 4b)] (two components, Ag and Sn)
Example 1 except that the metal paste (composition 4) having the composition (region A) of (Ag, Cu, Sn) = (29,0,71) was used instead of the metal paste (composition 1). It was verified in the same way as.

When the firing temperature was 450 ° C. (Example 4a), 0.5 mm, 1 mm, and 2 mm copper plates could be joined, but 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

On the other hand, when the firing temperature is 500 ° C. (Example 4b), any copper plate of 0.5 mm, 1 mm, or 3 mm can be bonded, and good results can be obtained in the bondability evaluation, appearance evaluation, and durability reliability evaluation. , A rank.

[Example 5 (5a, 5b)] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 5) having the composition (region A) of (Ag, Cu, Sn) = (35, 13, 52) was used instead of the metal paste (composition 1). It was verified in the same way as.

When the firing temperature was 450 ° C. (Example 5a), 0.5 mm, 1 mm, and 2 mm copper plates could be joined, but 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

On the other hand, when the firing temperature is 500 ° C. (Example 5b), any copper plate of 0.5 mm, 1 mm, or 3 mm can be bonded, and good results can be obtained in the bondability evaluation, appearance evaluation, and durability reliability evaluation. , A rank.

[Example 6] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 6) having the composition (region A) of (Ag, Cu, Sn) = (67,12,21) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., any copper plate of 0.5 mm, 1 mm, or 3 mm could be joined, and good results were obtained in the bondability evaluation, appearance evaluation, and durability reliability evaluation, and the rank was A. ..

[Example 7 (7a, 7b, 7c)] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 7) having the composition (region A) of (Ag, Cu, Sn) = (65,2,33) was used instead of the metal paste (composition 1). It was verified in the same way as.

When the firing temperature is 600 ° C. (Example 7a) and 700 ° C. (Example 7c), any copper plate of 0.5 mm, 1 mm, or 3 mm can be joined, and the bondability evaluation, appearance evaluation, and durability reliability evaluation can be performed. Good results (rank a or b) were obtained in both cases, and the rank was A.

Comparing Examples 7a and 7c, Example 7a having a low firing temperature was superior in appearance evaluation, whereas Example 7c having a high firing temperature was superior in durability reliability evaluation. Was there.

On the other hand, when the firing temperature is set to 650 ° C. (Example 7b), any copper plate of 0.5 mm, 1 mm, or 3 mm can be bonded, and the bondability evaluation, appearance evaluation, and durability reliability evaluation all have good results (all a). Rank) was obtained, and it became A rank.

[Example 8 (8a, 8b, 8c)] (three components of Ag, Cu, Sn)
Example 1 except that the metal paste (composition 8) having the composition (region A) of (Ag, Cu, Sn) = (62,11,27) was used instead of the metal paste (composition 1). It was verified in the same way as.

When the firing temperature is 600 ° C. (Example 8a), any copper plate of 0.5 mm, 1 mm, or 3 mm can be joined, and the bondability evaluation, appearance evaluation, and durability reliability evaluation all have good results (a or c rank). ) Was obtained, and it became A rank.

When the firing temperature is 700 ° C. (Example 8c), any copper plate of 0.5 mm, 1 mm, or 3 mm can be bonded as in Example 8a, and the bondability evaluation, appearance evaluation, and durability reliability evaluation are all good. A good result (rank a or b) was obtained, and it became rank A.

Comparing Examples 8a and 8c, Example 8a having a low firing temperature was superior in appearance evaluation, whereas Example 8c having a high firing temperature was superior in durability reliability evaluation. Was there.

On the other hand, when the firing temperature is set to 650 ° C. (Example 8b), any copper plate of 0.5 mm, 1 mm, or 3 mm can be bonded, and the bondability evaluation, appearance evaluation, and durability reliability evaluation all have good results (all a). Rank) was obtained, and it became A rank.

[Example 9 (9a, 9b)] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 9) having the composition (region A) of (Ag, Cu, Sn) = (44, 12, 44) was used instead of the metal paste (composition 1). It was verified in the same way as.

When the firing temperature is set to 550 ° C. (Example 9a), any copper plate of 0.5 mm, 1 mm, or 3 mm can be bonded, and the bondability evaluation, appearance evaluation, and durability reliability evaluation all have good results (all a rank). Was obtained, and it became A rank.

On the other hand, when the firing temperature is 600 ° C. (Example 9b), any copper plate of 0.5 mm, 1 mm, or 3 mm can be bonded, and the bondability evaluation, appearance evaluation, and durability reliability evaluation all have good results (a or). B rank) was obtained, and it became A rank.

[Example 10 (10a, 10b)] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 10) having the composition (region A) of (Ag, Cu, Sn) = (32, 6, 62) was used instead of the metal paste (composition 1). It was verified in the same way as.

When the firing temperature was 450 ° C. (Example 10a), 0.5 mm, 1 mm, and 2 mm copper plates could be joined, but 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

On the other hand, when the firing temperature is set to 500 ° C. (Example 10b), any copper plate of 0.5 mm, 1 mm, or 3 mm can be bonded, and the bondability evaluation, appearance evaluation, and durability reliability evaluation all have good results (all a). Rank) was obtained, and it became A rank.

[Example 11] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 11) having the composition (region A) of (Ag, Cu, Sn) = (43,2,55) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature is 600 ° C., any copper plate of 0.5 mm, 1 mm, or 3 mm can be joined, and good results (all a rank) are obtained in the bondability evaluation, appearance evaluation, and durability reliability evaluation. It became A rank.

[Example 12] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 12) having the composition (region A) of (Ag, Cu, Sn) = (51, 13, 36) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature is 600 ° C., any copper plate of 0.5 mm, 1 mm, or 3 mm can be joined, and good results (all a rank) are obtained in the bondability evaluation, appearance evaluation, and durability reliability evaluation. It became A rank.

[Example 13 (13a, 13b)] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 13) having the composition (region B) of (Ag, Cu, Sn) = (56, 19, 25) was used instead of the metal paste (composition 1). It was verified in the same way as.

When the firing temperature was 600 ° C. (Example 13a), 0.5 mm, 1 mm, and 2 mm copper plates could be joined, but 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

When the firing temperature was 700 ° C. (Example 13b), unlike Example 13a, 0.5 mm and 1 mm copper plates could be bonded, but 2 mm and 3 mm copper plates could not be bonded. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and the grade was C.

Comparing Examples 13a and 13b, Example 13a having a lower firing temperature was superior in bondability and appearance evaluation. Both endurance reliability evaluations were excellent.

[Example 14 (14a, 14b)] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 14) having the composition (region B) of (Ag, Cu, Sn) = (48, 32, 20) was used instead of the metal paste (composition 1). It was verified in the same way as.

When the firing temperature was 600 ° C. (Example 14a), 0.5 mm and 1 mm copper plates could be joined, but 2 mm and 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and the grade was C.

When the firing temperature was 700 ° C. (Example 14b), unlike Example 14a, 0.5 mm, 1 mm, and 2 mm copper plates could be bonded, but 3 mm copper plates could not be bonded. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

Comparing Examples 14a and 14b, Example 14a having a low firing temperature was superior in appearance evaluation, whereas bonding resistance and durability reliability were evaluated in Example 14b having a high firing temperature. Was better.

[Example 15] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 15) having the composition (region B) of (Ag, Cu, Sn) = (58, 25, 17) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., 0.5 mm, 1 mm, and 2 mm copper plates could be joined, but 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

[Example 16] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 16) having the composition (region B) of (Ag, Cu, Sn) = (47, 40, 13) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., 0.5 mm, 1 mm, and 2 mm copper plates could be joined, but 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

[Example 17] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 17) having the composition (region C) of (Ag, Cu, Sn) = (43,46,11) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., 0.5 mm and 1 mm copper plates could be joined, but 2 mm and 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and the grade was C.

[Example 18] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 18) having the composition (region C) of (Ag, Cu, Sn) = (23, 62, 15) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., 0.5 mm and 1 mm copper plates could be joined, but 2 mm and 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and the grade was C.

[Example 19] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 19) having the composition (region C) of (Ag, Cu, Sn) = (15, 65, 20) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., 0.5 mm and 1 mm copper plates could be joined, but 2 mm and 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and the grade was C.

[Example 20] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 20) having the composition (region C) of (Ag, Cu, Sn) = (23,53,24) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., 0.5 mm and 1 mm copper plates could be joined, but 2 mm and 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and the grade was C.

[Example 21] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 21) having the composition (region C) of (Ag, Cu, Sn) = (33, 54, 13) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., 0.5 mm and 1 mm copper plates could be joined, but 2 mm and 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and the grade was C.

[Example 22] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 22) having the composition (region C) of (Ag, Cu, Sn) = (22, 46, 32) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., 0.5 mm and 1 mm copper plates could be joined, but 2 mm and 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and the grade was C.

[Example 23] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 23) having the composition (region C) of (Ag, Cu, Sn) = (30, 25, 45) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 600 ° C., 0.5 mm and 1 mm copper plates could be joined, but 2 mm and 3 mm copper plates could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and the grade was C.

[Example 24] (two components of Cu and Sn)
Example 1 except that the metal paste (composition 24) having the composition (region D) of (Ag, Cu, Sn) = (0,59,41) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., a 0.5 mm copper plate could be joined, but a 1 mm and 3 mm copper plate could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked D.

[Example 25 (25a, 25b)] (two components of Cu and Sn)
Example 1 except that the metal paste (composition 25) having the composition (region D) of (Ag, Cu, Sn) = (0, 40, 60) was used instead of the metal paste (composition 1). It was verified in the same way as.

When the firing temperature was 600 ° C. (Example 25a), a 0.5 mm copper plate could be joined, but a 1 mm and 3 mm copper plate could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked D.

When the firing temperature was 700 ° C. (Example 25b), a 0.5 mm copper plate could be bonded, but a 1 mm and 3 mm copper plate could not be bonded, as in Example 25a. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked D.

Comparing Examples 25a and 25b, Example 25a having a low firing temperature was superior in appearance evaluation, whereas Example 25b having a high firing temperature was superior in durability reliability evaluation. Was there.

[Example 26] (Two components of Cu and Sn)
Instead of the metal paste (composition 1), a metal paste (composition 26) having a composition (region D) of (Ag, Cu, Sn) = (0,20,80) was used. When the firing temperature was 600 ° C., a 0.5 mm copper plate could be joined, but a 1 mm and 3 mm copper plate could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked D.

[Example 27] (two components of Cu and Sn)
Example 1 except that the metal paste (composition 27) having the composition (region D) of (Ag, Cu, Sn) = (0,13,87) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 450 ° C., a 0.5 mm copper plate could be joined, but a 1 mm and 3 mm copper plate could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked D.

[Example 28] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 28) having the composition (region D) of (Ag, Cu, Sn) = (9,48,43) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 700 ° C., a 0.5 mm copper plate could be joined, but a 1 mm and 3 mm copper plate could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked D.

[Example 29] (three components of Ag, Cu, and Sn)
Example 1 except that the metal paste (composition 29) having the composition (region D) of (Ag, Cu, Sn) = (15, 22, 63) was used instead of the metal paste (composition 1). It was verified in the same way as. When the firing temperature was 600 ° C., a 0.5 mm copper plate could be joined, but a 1 mm and 3 mm copper plate could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked D.

[Reference Example 1] (Composition not included in regions A to D)
The same as in Example 1 except that the metal paste (composition 30) having the composition of (Ag, Cu, Sn) = (80, 0, 20) was used instead of the metal paste (composition 1). I verified it. When the firing temperature was 450 ° C., 600 ° C., or 700 ° C., even a 0.5 mm copper plate could not be joined, so the rank was E.

[Reference Example 2] (Composition not included in regions A to D)
The same as in Example 1 except that the metal paste (composition 31) having the composition of (Ag, Cu, Sn) = (65, 25, 10) was used instead of the metal paste (composition 1). I verified it. When the firing temperature was 450 ° C., 600 ° C., or 700 ° C., even a 0.5 mm copper plate could not be joined, so the rank was E.

[Reference Example 3] (Composition not included in regions A to D)
Instead of the metal paste (composition 1), a metal paste (composition 32) having the composition of (Ag, Cu, Sn) = (55, 40, 5) was used. When the firing temperature was 450 ° C., 600 ° C., or 700 ° C., even a 0.5 mm copper plate could not be joined, so the rank was E.

[Reference Example 4] (Composition not included in regions A to D)
The same as in Example 1 except that the metal paste (composition 33) having the composition of (Ag, Cu, Sn) = (19, 67, 14) was used instead of the metal paste (composition 1). I verified it. When the firing temperature was 450 ° C., 600 ° C., or 700 ° C., even a 0.5 mm copper plate could not be joined, so the rank was E.

[Reference Example 5] (Composition not included in regions A to D)
The same as in Example 1 except that the metal paste (composition 34) having the composition of (Ag, Cu, Sn) = (0,65,35) was used instead of the metal paste (composition 1). I verified it.
When the firing temperature was 450 ° C., 600 ° C., or 700 ° C., even a 0.5 mm copper plate could not be joined, so the rank was E.

[Reference Example 6] (Composition not included in regions A to D)
The same as in Example 1 except that the metal paste (composition 35) having the composition of (Ag, Cu, Sn) = (0,10,90) was used instead of the metal paste (composition 1). I verified it. When the firing temperature was 450 ° C., 600 ° C., or 700 ° C., even a 0.5 mm copper plate could not be joined, so the rank was E.

[Reference Example 7] (Composition not included in regions A to D)
The same as in Example 1 except that the metal paste (composition 36) having the composition of (Ag, Cu, Sn) = (20, 0, 80) was used instead of the metal paste (composition 1). I verified it. When the firing temperature was 450 ° C., 600 ° C., or 700 ° C., even a 0.5 mm copper plate could not be joined, so the rank was E.

[Reference Example 8] (Composition not included in regions A to D)
The same as in Example 1 except that the metal paste (composition 37) having the composition of (Ag, Cu, Sn) = (30, 10, 60) was used instead of the metal paste (composition 1). I verified it. When the firing temperature was 450 ° C., 600 ° C., or 700 ° C., even a 0.5 mm copper plate could not be joined, so the rank was E.

[Reference Example 9] (Composition not included in regions A to D)
The same as in Example 1 except that the metal paste (composition 38) having the composition of (Ag, Cu, Sn) = (73, 9, 18) was used instead of the metal paste (composition 1). I verified it. When the firing temperature was 450 ° C., 600 ° C., or 700 ° C., even a 0.5 mm copper plate could not be joined, so the rank was E.

[Reference Example 10] (Composition not included in regions A to D)
The same as in Example 1 except that the metal paste (composition 39) having the composition of (Ag, Cu, Sn) = (34, 56, 10) was used instead of the metal paste (composition 1). I verified it. When the firing temperature was 450 ° C., 600 ° C., or 700 ° C., even a 0.5 mm copper plate could not be joined, so the rank was E.

The results are shown in Tables 1-10 and FIG.

As is clear from Tables 1 to 10 and FIG. 3, in the example using the metal paste composition in which the composition ratio of Ag, Cu and Sn was adjusted to a specific region on the triangular coordinates, the average thickness was 0.5 mm or more. Even a thick copper plate could be effectively bonded to a ceramic substrate at a low temperature of 700 ° C. or lower. Further, in the examples, not only high bondability but also durability reliability (heat impact resistance) and appearance evaluation were good, and these characteristics were satisfied in a well-balanced manner.

In addition, on the triangular coordinates of FIG. 3, the composition (metal paste) that can be bonded at the firing temperature (bonding temperature) of 700 ° C. is "●" (circle), and the composition that can be bonded at 600 ° C. is "■" (. Square), the composition that could be bonded at 500 ° C is "◆" (ryo), the composition that could be bonded at 450 ° C is "▲" (triangle), and the composition that could not be bonded at any temperature is "x" (x). (X) is indicated for each (Note that for compositions that can be joined at multiple temperatures, they are indicated according to the higher temperature).

Further, in FIG. 3, the embodiment is referred to as “actual” and the reference example is referred to as “reference example”, and the corresponding numbers are indicated immediately after that (for example, Example 1 is “actual 1” and reference example 1 is “reference example 1”. ").

The composition (composition having a melting point of about 600 to 650 ° C. at the time of alloying) that could be bonded at a firing temperature of 700 ° C. is (Ag, Cu, Sn) = (74, 0, 26): Example 1, (67). , 12, 21): Example 6, (58, 25, 17): Example 15, (47, 40, 13): Example 16, (43, 46, 11): Example 17, (33, 54). , 13): Example 21, (23,62,15): Example 18, (15,65,20): Example 19, and (0,59,41): Line segment connecting Example 24 in this order. Since it is scattered in the vicinity of the boundary line X composed of, it can be inferred that the solid-liquid boundary at about 600 to 650 ° C. exists in the vicinity of the boundary line X. Further, the composition (composition having a melting point of about 400 to 450 ° C. at the time of alloying) that could be bonded at a firing temperature of 450 to 500 ° C. is (Ag, Cu, Sn) = (0,13,87): Example. 27, (35, 13, 52): Example 5, (32, 6, 62): Example 10 and (29, 0, 71): Boundary line Y composed of line segments connecting Example 4 in this order. Since it is scattered in the vicinity, it can be inferred that the solid-liquid boundary at about 400 to 450 ° C. exists near the boundary line Y. Therefore, it can be inferred that the region between the boundary line X and the boundary line Y (the composition of the alloy having a melting point of about 400 to 650 ° C.) becomes a region where a thick copper plate can be bonded at a low temperature of 700 ° C. or lower.

In fact, all the compositions in which the copper plates having a thickness of 0.5 mm or more can be joined are the compositions in the region (regions A to D) between the boundary line X and the boundary line Y, and are reference examples outside the region. In the above composition, a copper plate having a thickness of 0.5 mm or more could not be bonded at a low temperature.

Further, among the regions (regions A to D) between the boundary line X and the boundary line Y, the comprehensive evaluation of the copper-coated substrates (Examples 1 to 12) produced by the composition of the region A is rank A. , The overall evaluation of the copper-coated substrate (Examples 13 to 16) prepared with the composition of region B is rank B, and the comprehensive evaluation of the copper-coated substrate (Examples 17 to 23) prepared with the composition of region C is The overall evaluation of the copper-coated substrates (Examples 24 to 29) having rank C and prepared from the composition of region D was rank D. Therefore, the closer it is from the area D side to the A side (in the order of areas D, C, B, A) (preferably toward the left side (particularly the lower left side) in the areas A to D), the appearance and durability reliability. It was found that high bondability can be ensured while achieving both, and in particular, the composition of region A is most suitable for thick copper.

In the specific brazing filler metal components used in the examples of Patent Documents 1 to 7, each atomic ratio (Ag, Cu, Sn) to the total amount of Ag, Cu and Sn (100 atm%) [unit: atm%]. Is calculated and is in the range shown in Table 11 below.

As is clear from Table 11, in the composition ratios in Patent Documents 1 to 7, the proportion of Sn is small in all of them, and on the triangular coordinates of FIG. 3, they are far to the left of the boundary line X (particularly, regions A to C). Located in position (outside the area). Among these, the composition ratio of Patent Document 7, which seems to be relatively close to the region of the present application (regions B and C), is about (Ag, Cu, Sn) = (55.5, 40.6, 3.9). However, since the comprehensive evaluation of Reference Example 3 (Ag, Cu, Sn) = (55, 40, 5) of the present application, which is close to the composition ratio of Patent Document 7, is E rank, the conventional brazing filler metal component is used. It is presumed that the copper plate cannot be joined due to its high bondability.

[Example 30] (Example in which the types of the two components Ag and Sn and the active metal component are changed)
The firing temperature was verified as 600 ° C. by the same method as in Example 3 except that the metal paste (composition 40) in which the active metal component was changed to zirconium hydride was used. In Example 30, 0.5 mm, 1 mm, and 2 mm copper plates could be bonded to Example 3, which was ranked A, but 3 mm copper plates could not be bonded. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

[Example 31 (31a, 31b)] (Example in which the types of the three components Ag, Cu, and Sn and the active metal component are changed)
It was verified by the same method as in Example 7 (7a, 7c) except that the metal paste (composition 41) in which the active metal component was changed to zirconium hydride was used. With respect to Example 7 (7a, 7c) having an A rank, the firing temperature was 0.5 mm, 1 mm, or 2 mm in both cases of 600 ° C. (Example 31a) and 700 ° C. (Example 31b). The copper plate could be joined, but the 3 mm copper plate could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

[Comparative Example 1] (Example not containing the active metal component)
The firing temperatures were verified as 450 ° C, 600 ° C, and 700 ° C by the same method as in Example 7 except that the metal paste (composition 42) containing no active metal component was used, but any firing temperature was used. , Even a 0.5 mm copper plate could not be joined, so it was ranked E.

[Example 32 (32a, 32b)] (Example in which the ratios of the three components Ag, Cu, and Sn and the active metal component are changed)
Verification by the same method as in Example 7 (7a, 7c) except that the metal paste (composition 43) in which the ratio of the active metal component to 100 parts by mass of the inactive metal component was reduced to 0.5 parts by mass was used. did. At both the firing temperatures of 600 ° C. (Example 32a) and 700 ° C. (Example 32b), 0.5 mm, 1 mm, and 2 mm copper plates could be bonded, but 3 mm copper plates could not be bonded. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

[Example 33 (33a, 33b)] (Example in which the ratios of the three components Ag, Cu, and Sn and the active metal component are changed)
It was verified by the same method as in Example 7 (7a, 7c) except that the metal paste (composition 44) in which the ratio of the active metal component was increased to 10.0 parts by mass was used. At any of the firing temperatures of 600 ° C. (Example 33a) and 700 ° C. (Example 33b), 0.5 mm, 1 mm, and 3 mm copper plates can be bonded in the same manner as in Example 7 (7a, 7c), and the bondability is as good as possible. Good results were obtained in all of the evaluation, appearance evaluation, and durability reliability evaluation, and the product was ranked A.

[Example 34 (34a, 34b)] (Example in which the ratios of the three components Ag, Cu, and Sn and the active metal component are changed)
It was verified by the same method as in Example 7 (7a, 7c) except that the metal paste (composition 45) in which the ratio of the active metal component was increased to 30.0 parts by mass was used. At both the firing temperatures of 600 ° C. (Example 34a) and 700 ° C. (Example 34b), 0.5 mm, 1 mm, and 2 mm copper plates could be bonded, but 3 mm copper plates could not be bonded. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

The results are shown in Tables 12-13.

From the results shown in Tables 12 to 13, the bonding was not possible in Comparative Example 1 containing no active metal component, whereas in each of the examples, the bonding property, appearance and durability reliability were excellent. Further, as the active metal component, titanium hydride is particularly preferable from the viewpoint of bondability and durability reliability. Further, the ratio of the active metal component to 100 parts by mass of the non-active metal component gives good results at 0.5 to 30 parts by mass, and it can be said that it is particularly preferably about 3 to 10 parts by mass.

[Examples 35 to 36] (Example in which the type of ceramic substrate is changed with respect to Example 7c)
The verification was performed in the same manner as in Example 7c, except that an alumina substrate (Example 35) or an aluminum nitride substrate (Example 36) was used as the ceramic substrate. The results are shown in Table 14.

In the case of the alumina substrate (Example 35), the copper plates of 0.5 mm, 1 mm and 2 mm could be bonded at the same firing temperature of 700 ° C as in Example 7c, but the copper plates of 3 mm could not be bonded. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

In the case of the aluminum nitride substrate (Example 36), the copper plates of 0.5 mm, 1 mm and 2 mm could be bonded at the same firing temperature of 700 ° C. as in Example 7c, but the copper plates of 3 mm could not be bonded. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B.

Comparing Examples 7c, 35 and 36, Example 7c using a silicon nitride substrate has better bondability than Examples 35 and 36, while Examples 35 and 36 evaluate the appearance. It was excellent.

[Example 37] (Example in which the three components of Ag, Cu, and Sn, and the type of copper plate are changed)
The firing temperature was verified as 650 ° C. by the same method as in Example 7b except that the type of the copper plate was changed from oxygen-free copper to copper-tungsten alloy. In Example 37, a 2 mm copper plate (copper-tungsten alloy) could be bonded, whereas a 3 mm copper plate (oxygen-free copper) could be bonded to the A rank in Example 7b, but a 3 mm copper plate (copper-tungsten alloy) could be bonded. ) Could not be joined. Good results were obtained in both the appearance evaluation and the durability reliability evaluation, and it was ranked B. The results are shown in Table 15.

The bonding agent (bonding material or metal paste) of the present invention can be effectively used as an active metal brazing material for bonding a copper plate and a ceramic substrate. In particular, even if a thick copper plate is used, it exhibits excellent bondability and durability reliability, and also has a good appearance. Therefore, the obtained copper-clad substrate can be used for power generation equipment, automobiles (electric vehicles (EV), hybrid cars (HEV), etc. Suitable as a circuit board for power modules for power conversion and / or control in various applications such as fuel cell vehicles), railway vehicles (Shinkansen, etc.), home appliances (air conditioners, refrigerators, etc.), elevators, etc. can.

1 ... Precursor (laminated body) of copper-clad substrate
2 ... Ceramic substrate (insulating substrate)
3a, 3b ... Metal paste layer (bonding composition layer or bonding layer precursor layer)
4a, 4b ... Copper plate 10 ... Copper-clad substrate 13a, 13b ... Bonding layer

Claims (13)

A metal paste containing at least one selected from Ag and Cu, an inactive metal component (1) containing Sn; an active metal component (2) containing an active metal; and an organic vehicle (3);
The composition ratio of Ag, Cu and Sn in the non-active metal component (1) is defined as (Ag, Cu, Sn) on triangular coordinates as the ratio of each atom to the total amount of Ag, Cu and Sn [unit: atm%]. When expressed, the composition ratio is (Ag, Cu, Sn) = (74,0,26), (67,12,21), (58,25,17), (47,40,13), (43). , 46,11), (33,54,13), (23,62,15), (15,65,20), (0,59,41), (0,13,87), (35,13) , 52), (32,6,62) and (29,0,71) in the area or its outer edge.
The outer edge is represented by (P _Ag + α, P _Cu + β, P _Sn + γ), where (PA _Ag , P _Cu , P _Sn ) is the coordinate of an arbitrary point P on the boundary line that divides the region. A bonding agent which is a region formed by the point Q (where α, β and γ satisfy the following formula).
-2 ≤ α ≤ 2
-2 ≤ β ≤ 2
-2 ≤ γ ≤ 2
α + β + γ = 0 The composition ratios of Ag, Cu and Sn in the inactive metal component (1) are (Ag, Cu, Sn) = (74,0,26), (67,12,21), (58,25,17). , (47,40,13), (43,46,11), (33,54,13), (23,62,15), (15,65,20), (22,46,32), ( 30, 25, 45), (35, 13, 52), (32, 6, 62) and (29, 0, 71), the bonding agent according to claim 1, which is in the region surrounded by or the outer edge thereof. The composition ratios of Ag, Cu and Sn in the inactive metal component (1) are (Ag, Cu, Sn) = (74,0,26), (67,12,21), (58,25,17). , (47,40,13), (35,13,52), (32,6,62) and (29,0,71). Agent. The composition ratios of Ag, Cu and Sn in the inactive metal component (1) are (Ag, Cu, Sn) = (74,0,26), (67,12,21), (51,13,36). , (35,13,52), (32,6,62) and (29,0,71). The bonding agent according to any one of claims 1 to 4, wherein the active metal is at least one selected from Ti, Zr, Hf, and Nb. The invention according to any one of claims 1 to 5, wherein the ratio of the active metal component (2) is 0.5 to 30 parts by mass with respect to 100 parts by mass of the total amount of the non-active metal component (1). Bonding agent. The bonding agent according to any one of claims 1 to 6, which is an active metal brazing material for forming a copper-coated substrate in which a copper plate containing copper and a ceramic substrate are bonded. The bonding agent according to claim 7, wherein the copper plate has an average thickness of 0.5 to 5 mm. The bonding agent according to claim 7 or 8, wherein the ceramic substrate contains at least one selected from silicon nitride, aluminum nitride, and alumina. The bonding agent according to any one of claims 7 to 9, wherein the copper-clad substrate is a circuit board for a power module. A copper-coated substrate comprising the copper plate and the ceramic substrate, and a bonding layer interposed between the copper plate and the ceramic substrate and formed of a fired product of the bonding agent according to any one of claims 7 to 10. .. A laminate including the copper plate and the ceramic substrate and a metal paste layer interposed between the copper plate and the ceramic substrate and formed with the bonding agent according to any one of claims 7 to 10 is formed. With the laminating process;
The method for manufacturing a copper-coated substrate according to claim 11, further comprising a bonding step of heating the laminated body obtained in this laminating step to form a bonding layer in which the metal paste layer is fired. The manufacturing method according to claim 12, wherein the heating temperature in the joining step is 430 to 710 ° C.

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