Metal / ceramic joint, brazing material, method for manufacturing a metal / ceramic joint, and method for manufacturing a brazing material.

Abstract

Disclosed is a metal / ceramic joined body which has a metal member, a ceramic member that is joined to the metal member, and a bonding layer that is formed on the joined surface between the metal member and the ceramic member, the bonding layer containing Cu and Mg, and additionally containing at least one active metal element that is selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er. The bonding layer has a non-layered MgO phase that contains MgO.

Description

[Technical Field]

[0001] This disclosure relates to a metal / ceramic joint, a brazing material, a method for manufacturing a metal / ceramic joint, and a method for manufacturing a brazing material. [Background technology]

[0002] Metal / ceramic joints, which are constructed by joining metal and ceramic components, are in high demand as insulating circuit boards for power electronics semiconductor devices such as inverters and converters, and are undergoing improvements in current density and miniaturization. As a result, higher thermal stress is generated, requiring circuit boards with long lifespan and high strength, and consequently, high-strength metal / ceramic joints.

[0003] In bonding metals and ceramics, particularly in insulating circuit boards used in semiconductor devices, bonding methods such as DCB (Direct Copper Bonding), which uses a eutectic of copper (Cu) and copper oxide (CuO) to directly heat-bond Cu and oxide ceramics, and AMB (Active Metal Brazing), which uses an active metal brazing material, are employed.

[0004] Among these, the AMB method has attracted attention as a bonding method that can obtain high bonding strength, and Ag-Cu-Ti-based brazing materials are used as typical bonding materials. For example, in Patent Document 1, after arranging Ag-Cu-Sn-Ti-based brazing materials on a ceramic substrate, Cu is laminated, resulting in a 1.0 × 10⁻⁶ bond. -3 A metal / ceramic bond is obtained by performing heat treatment at a temperature between 780°C and 850°C in a vacuum of Pa or less.

[0005] Furthermore, there have been studies on brazing material compositions that do not contain Ag (silver). For example, Patent Document 2 proposes a ceramic circuit board in which a copper plate and a ceramic substrate are joined using a Cu-Mg-Ti (carbon alloy) brazing material. According to Patent Document 2, a metal / ceramic bond can be obtained by laminating a Cu plate and a ceramic substrate via an activated metal foil and a magnesium (Mg) foil, and then heat-treating them in the range of 700°C to 830°C. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 6743073 [Patent Document 2] International Publication No. 2021 / 033421 [Overview of the project] [Problems that the invention aims to solve]

[0007] In joining methods using activated metal brazing materials, the activated metal and ceramics react at the interface, forming an interfacial reaction layer that provides a joint with a certain degree of high joint strength and reliability. However, because metal and ceramic members have significantly different coefficients of thermal expansion, strain and defects can increase in the joint layer between the metal and ceramic members, potentially leading to a decrease in joint strength and reliability.

[0008] As described in Patent Document 1, when Cu and aluminum nitride (AlN) or silicon nitride (Si3N4) are joined via an Ag-Cu-Sn-Ti brazing material, the thermal expansion coefficient of Si3N4 is lower than that of the bonding layer placed between Cu and Si3N4. Therefore, problems may arise in reliability during thermal cycling tests (hereinafter referred to as thermal cycling reliability).

[0009] Furthermore, as described in Patent Document 2, by dispersing an activated metal oxide phase with a low coefficient of thermal expansion within the bonding layer, thermal stress caused by the difference in the coefficients of thermal expansion between the copper member and the ceramic member can be alleviated. However, since a layer of magnesium oxide (MgO), which is prone to brittle fracture, is formed between the copper member and the ceramic member, the bonding strength may be reduced.

[0010] The purpose of this disclosure is to provide a metal / ceramic joint with high bonding strength and high thermal cycling reliability. [Means for solving the problem]

[0011] According to one aspect of this disclosure, Metal components and A ceramic member joined to the aforementioned metal member, A bonding layer is formed on the bonding surface between the metal member and the ceramic member, and further comprises Cu and Mg, and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er. The bonding layer contains a non-layered MgO phase containing MgO. In a cross-section including the metal member, the ceramic member, and the bonding layer, the bonding layer is dispersed in both the thickness direction and the creepage direction, and exists in a form that extends in a curved manner. A metal / ceramic joint is provided.

[0012] According to other aspects of this disclosure, Used for joining metal components and ceramic components, It contains 50-80 at% Cu, 5-20 at% Mg, and a total of 0.1-10 at% of at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er. The aforementioned Mg is present in at least a portion in the form of MgO, A brazing material is provided in which the Cu and Mg are contained in a state where the average particle size is 45 μm or less.

[0013] According to yet another aspect of this disclosure, A step of arranging a metal member and a ceramic member to be laminated via a brazing material; A step of applying a hydrogen reduction treatment to the arranged brazing material, Through the aforementioned hydrogen reduction treatment of the brazing material Between the metal member and the ceramic member stacked A step of heating and holding the laminate while applying pressure in the lamination direction; The method for manufacturing a metal / ceramic joint body includes: As the brazing material, Cu is 50 - 80 at%, Mg is 5 - 20 at%, and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, Er is included in a total proportion of 0.1 - 10 at%. At least a part of the Mg is included in the form of MgO, and the Cu and the Mg are included in a state where the average particle size is 45 μm or less. ru A method for manufacturing a metal / ceramic joint body is provided.

Advantages of the Invention

[0014] According to the present disclosure, it is possible to provide a metal / ceramic joint body having high joint strength and high thermal cycle reliability.

Brief Description of the Drawings

[0015] [Figure 1] FIG. 1 is a partial cross-sectional schematic view of a metal / ceramic joint body 100 in one aspect of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional photograph (SEM image) of the first layer 31 and its periphery. [Figure 3] FIG. 3 is a magnified photograph (STEM image) of the MgO phase 33. [Figure 4] FIG. 4 is an electron energy loss (EELS) spectrum obtained by analyzing the MgO phase 33 with a scanning transmission electron microscope. [Figure 5] FIG. 5(a) is a diagram schematically showing the shear stress applied to the joint layer 30, and FIG. 5(b) is a diagram schematically showing the tensile stress applied to the joint layer 30. [Figure 6]Figure 6(a) shows the arrangement of the metal member 10 and the ceramic member 20 via the brazing material 50, Figure 6(b) shows the heating of the laminate of the metal member 10 and the ceramic member 20 under pressure, and Figure 6(c) shows the manufactured metal / ceramic joint 100. [Figure 7] Figure 7 is a cross-sectional photograph of the joint layer where a large void 34L occurred. [Figure 8] Figure 8 is a schematic diagram illustrating the process of conducting a shear strength test. [Modes for carrying out the invention]

[0016] <One aspect of this disclosure> Hereinafter, one aspect of this disclosure will be described with reference to the aforementioned drawings. Note that the drawings used in the following description are all schematic. The dimensions and proportions of the elements shown in the drawings do not necessarily correspond to reality. Furthermore, the dimensions and proportions of the elements do not necessarily correspond between drawings. In this specification, "A to B" means a numerical range of "A or greater and B or less".

[0017] (1) Composition of the metal / ceramics joint As shown in Figure 1, the metal / ceramics joint 100 includes a metal member 10, a ceramic member 20 joined to the metal member 10, and a bonding layer 30 formed on the joint surface between the metal member 10 and the ceramic member 20.

[0018] The metal member 10 is made of, for example, pure copper, copper alloy, pure nickel, nickel alloy, etc. As pure copper, for example, oxygen-free copper, tough pitch copper, and phosphorus-deoxidized copper can be used. As copper alloy, an alloy can be used in which copper (Cu) is the main element and at least one element selected from the group consisting of, for example, zinc (Zn), tin (Sn), phosphorus (P), aluminum (Al), beryllium (Be), cobalt (Co), nickel (Ni), iron (Fe), and manganese (Mn) is added. There are no particular limitations on the shape or dimensions of the metal member 10, but when the metal / ceramics joint 100 is used as a component material of an insulating circuit board, for example, it can be a flat plate having a thickness in the range of 0.1 mm to 4.0 mm. In this invention, the case in which the metal member 10 is made of pure copper will be described.

[0019] The ceramic member 20 is composed of, for example, silicon nitride (Si3N4), aluminum nitride (AlN), silicon carbide (SiC), aluminum oxide (Al2O3), diamond, etc. There are no particular limitations on the shape or dimensions of the ceramic member 20, but when the metal / ceramic joint 100 is used as a component material for an insulating circuit board, it can be a flat plate having a thickness in the range of 0.2 mm to 4.0 mm. In this invention, the case in which the ceramic member 20 is made of silicon nitride (Si3N4) will be described.

[0020] A bonding layer 30 is formed between the metal member 10 and the ceramic member 20, along their bonding surfaces 10s and 20s. The bonding layer 30 contains copper (Cu) and magnesium (Mg), and further contains at least one active metal element selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), calcium (Ca), yttrium (Y), cerium (Ce), lanthanum (La), samarium (Sm), ytterbium (Yb), neodymium (Nd), gadolinium (Gd), erbium (Er), etc. When the ceramic member 20 is Si3N4 or AlN, it is particularly preferable to use Ti, V, Nb, Cr, Mo, or Ca as the active metal element, with Ti being particularly preferred. In this invention, the case in which Ti is used as the active metal element will be described.

[0021] As will be described later, the bonding layer 30 is formed by the reaction of a brazing material 50 containing Cu, Mg, and the aforementioned active metal element in predetermined proportions with the metal member 10 and the ceramic member 20, respectively. The brazing material 50 used in this embodiment is an Ag-free Cu-Mg type brazing material, for example, containing 50-80 at% Cu, 5-20 at% Mg, and a total of 0.1-10 at% active metal element (Ti in this embodiment). In other words, the brazing material 50 used in this embodiment contains 5-20 at% Mg and a total of 0.1-10 at% active metal element, with the remainder (after removing unavoidable impurities) consisting of Cu. By using such a brazing material 50 and performing bonding in the method described later, the bonding layer 30 in this embodiment will exhibit the following various characteristics.

[0022] As shown in Figure 1, the bonding layer 30 has a laminated structure consisting of a first layer 31 that forms the interface with the metal member 10 and a second layer 32 that forms the interface with the ceramic member 20 and is in contact with the first layer 31. The thickness of the first layer 31 is exemplified as 1 to 2000 μm, and the thickness of the second layer 32 is exemplified as 1 to 2000 nm.

[0023] Figure 2 is a cross-sectional image (SEM image) of the first layer 31 and its surrounding area. As shown in Figure 2, the first layer 31 has a solid solution phase 31A (light gray area in the figure) and a compound phase 31B (dark gray area in the figure).

[0024] The solid solution phase 31A mainly consists of a solid solution in which Mg is dissolved in Cu crystals. In addition, active metal elements such as Ti contained in the brazing material 50, and Si and Al contained in the ceramic component 20 may also be dissolved in the solid solution phase 31A.

[0025] Compound phase 31B mainly consists of intermetallic compounds containing Cu and Mg, such as compounds represented by the compositional formula MgCu2 (hereinafter also referred to as Cu-Mg alloys). Compound phase 31B may also contain precipitated intermetallic compounds containing the active metal element mentioned above. When Ti is selected as the active metal element, the intermetallic compounds containing the active metal element include at least one compound selected from the group of compounds represented by the compositional formulas Cu4Ti, Cu3Ti2, Cu2Ti, Cu4Ti3, CuTi, CuTi2, Ti5Si3, Ti3Si, CuTiSi, etc.

[0026] As shown in Figure 2, the bonding layer 30 (first layer 31) contains a non-layered MgO phase 33 containing magnesium oxide (MgO) (for example, the outer periphery of the region indicated by diameter R in Figure 2). In other words, for example, the MgO phase 33 in the bonding layer 30 (first layer 31) is not concentrated in any particular region, but is dispersed in both the thickness direction and the creepage direction (joint surface 10s, 20s direction) of the bonding layer 30. Furthermore, it is preferable that the MgO phase 33 exists in a curved manner without forming large clumps, as shown in Figure 2. The presence of the MgO phase 33 in the bonding layer 30 (especially the first layer 31) in this manner mitigates the generation of thermal stress caused by the difference in thermal expansion coefficients between the metal member 10 and the ceramic member 20, thereby improving bonding strength and thermal cycle reliability. Note that the illustration of the MgO phase 33 is omitted in Figure 1.

[0027] As shown in Figure 2, it is preferable that the MgO phase 33 exists in a shell-like manner, surrounding at least one of the solid solution phase 31A and the compound phase 31B. The presence of the MgO phase 33 in this manner mitigates the generation of thermal stress between the solid solution phase 31A and the compound phase 31B, thereby further improving bonding strength and thermal cycle reliability. Note that the statement that the MgO phase 33 surrounds at least one of the solid solution phase 31A and the compound phase 31B includes not only cases where the MgO phase 33 forms a closed space (closed curve in the cross-sectional photograph) and completely surrounds a certain region, but also cases where the MgO phase 33 is absent from a part of the outer periphery of the region. In this specification, for example, if the MgO phase 33 covers 80% or more of the surface area (outer periphery in the cross-sectional photograph) of the region, it will be expressed that the MgO phase 33 surrounds the region.

[0028] In the region surrounded by the MgO phase 33, it is preferable that the proportion of the solid solution phase 31A (e.g., area ratio in the cross-section) is 90% or more, or that the proportion of the compound phase 31B (e.g., area ratio in the cross-section) is 90% or more. This means that the MgO phase 33 is abundant at the boundary between the solid solution phase 31A and the compound phase 31B. The presence of the MgO phase 33 in this manner can mitigate the generation of thermal stress between the solid solution phase 31A and the compound phase 31B, thereby further improving the bonding strength and thermal cycle reliability.

[0029] The diameter R of the region surrounded by the MgO phase 33 is preferably, for example, 1 μm to 20 μm. This further improves the bonding strength and thermal cycle reliability. Note that diameter R may be the equivalent circle diameter of the region surrounded by the MgO phase 33 in a cross-sectional photograph as shown in Figure 2.

[0030] Figure 3 is a magnified image (STEM image) of the MgO phase 33. As shown in Figure 3, the MgO phase 33 is preferably formed by a large number of linked MgO particles. The thickness d of the MgO phase 33 is preferably, for example, 10 nm to 1 μm. Furthermore, the particle size of the MgO particles in the MgO phase 33 is preferably, for example, 10 nm to 30 nm. These factors can further improve bonding strength and thermal cycle reliability.

[0031] In the first layer 31, it is preferable that the MgO phase 33 is uniformly dispersed. Specifically, for example, the cross-section of the first layer 31 is 500 μm. 2 When the area ratio of the MgO phase 33 in the region is measured multiple times (e.g., three times) in different observation fields, it is preferable that the difference between the maximum and minimum values ​​of the area ratio of the MgO phase 33 is within 5%. This can further improve the bonding strength and thermal cycle reliability. When measuring the area ratio of the MgO phase 33 in the cross-section of the first layer 31, it may be calculated, for example, by image analysis of a cross-sectional photograph as shown in Figure 2, or the area of ​​the MgO phase 33 may be calculated by multiplying the sum of the equivalent circle diameters R of each region surrounded by the MgO phase 33 by the average thickness d of the MgO phase 33.

[0032] In the cross-section of the first layer 31 (for example, cross-section of 500 μm) 2 In the specified region, the area ratio of the MgO phase 33 is preferably, for example, 0.4% or more and 15% or less. If the area ratio of the MgO phase 33 is less than 0.4%, the effect of improving the bonding strength may be insufficient. In contrast, by setting the area ratio of the MgO phase 33 to 0.4% or more, the bonding strength can be sufficiently improved. On the other hand, if the area ratio of the MgO phase 33 exceeds 15%, the effect of improving thermal cycle reliability may decrease. In contrast, by setting the area ratio of the MgO phase 33 to 15% or less, thermal cycle reliability can be sufficiently improved.

[0033] Figure 4 shows an example of the electron energy loss (EELS) spectrum of MgO phase 33, analyzed using a scanning transmission electron microscope. As shown in Figure 4, EELS analysis of MgO phase 33 reveals that its spectrum has peaks (indicated by arrows in the figure) in the ranges of 50-80 eV and 530-560 eV.

[0034] When joining a metal member 10 and a ceramic member 20 using a brazing material containing Mg, there is a concern that voids and pinholes (hereinafter collectively referred to as voids) may occur in the first layer 31 due to the evaporation of Mg contained in the brazing material. Figure 7 shows an example of a cross-sectional photograph of the joined layer containing voids 34L caused by the evaporation of Mg, etc. In Figure 7, approximately 3500 μm 2 Within the field of view, the presence of void 34L with an equivalent circle diameter (the diameter of a circle with an area equal to the cross-sectional area of ​​void 34L) of 8 μm or larger can be confirmed. Note that the equivalent circle diameter of void 34L in the upper right of Figure 7 is approximately 9-10 μm, in the upper left it is 5 μm or larger, and in the lower left it is approximately 3-4 μm.

[0035] The presence of such large voids 34L reduces the bonding strength between the metal member 10 and the ceramic member 20. If a brazing material containing Mg and the aforementioned active metal elements individually, but without Cu, is used to bond the metal member 10 and the ceramic member 20, the Mg in the brazing material will evaporate rapidly, making the formation of voids 34L with an equivalent circular diameter exceeding 8 μm in the first layer 31 unavoidable. As a result, the bonding strength between the metal member 10 and the ceramic member 20 will be significantly reduced. Furthermore, in this case, bonding between the metal member 10 and the ceramic member 20 may become impossible altogether.

[0036] To address these challenges, in this embodiment, by using a brazing material 50 that contains not only Mg and active metal elements but also Cu in the above-mentioned proportions during bonding, we have succeeded in sufficiently suppressing the appearance of large voids 34L, for example, voids 34L with an equivalent circle diameter of 8 μm or more, in the bonded layer 30.

[0037] For example, in Figure 2, approximately 2000 μm 2 Within the field of view, no void 34L with an equivalent diameter of 8 μm or larger was observed, while only one void 34S with an equivalent diameter of approximately 1-2 μm was observed.

[0038] As described above, in this embodiment, when the first layer 31 is observed in a cross-section perpendicular to the bonding surfaces 10s and 20s, the bonding layer 30 has a thickness of approximately 10,000 μm. 2 Within any given field of view, not a single void 34L with an equivalent circular diameter of 8 μm or larger is observed, which is an extremely excellent characteristic. In other words, when the first layer 31 is observed in a cross section perpendicular to the bonding surfaces 10s and 20s, the number of voids with an equivalent circular diameter of 8 μm or larger is 10,000 μm. 2 There is less than one per person.

[0039] In this embodiment, when the first layer 31 is observed in a cross-section perpendicular to the bonding surfaces 10s and 20s, even if a void 34S is observed, its equivalent circular diameter is less than 8 μm, for example, less than 5 μm, preferably less than 3 μm.

[0040] Furthermore, in this embodiment, when the first layer 31 is observed in a cross-section perpendicular to the bonding surfaces 10s and 20s, voids 34S with an equivalent circle diameter of less than 8 μm, for example, voids 34S with an equivalent circle diameter greater than 2 μm but less than 8 μm, may be observed, but their number is approximately 10,000 μm. 2 Within any field of view, the number is very small, 10 or less, preferably 5 or less. In this embodiment, voids 34S with an equivalent circle diameter of 1 μm to 2 μm may also be observed, but their number is approximately 10,000 μm.2 Within any visual field, the number is 20 or less, preferably 10 or less, and is extremely small.

[0041] Among the bonding layer 30, the second layer 32 that constitutes the interface with the ceramic member 20 has titanium nitride (TiN), which is a nitride of an active metal element (Ti for the main body), as the main component (for example, 50 at% or more is TiN). When the ceramic member 20 is made of silicon nitride, a compound represented by the composition formula Ti5Si3 or the like may be included in the second layer 32. The active metal compound (for example, TiN) in the second layer 32 exists in a layer along the interface with the ceramic member 20, for example.

[0042] The second layer 32 may contain a nitride crystal X represented by the composition formula MgSiN2. The nitride crystal X may be unevenly distributed in the vicinity of the interface with the ceramic member 20 in the second layer 32, for example. When the thickness of the region where the nitride crystal X is unevenly distributed is set as Tx of the thickness of the second layer 32, it is 5% to 50% of Tx, preferably about 10% to 40%. For example, when the thickness Tx of the second layer 32 is about 2,500 nm, the thickness of the region where the nitride crystal X is unevenly distributed is about 10 nm to 150 nm, preferably about 20 nm to 100 nm. The presence of the nitride crystal X can be confirmed by using, for example, crystal analysis (TEM-PED method) in which precession electron beam diffraction method is applied to a transmission electron microscope for the second layer 32. Note that it is preferable that the second layer 32 in this aspect does not substantially contain a nitride crystal Y represented by the composition formula Mg3N2. In the main body, the nitride crystal Y has not been confirmed even by analysis using the TEM-PED method.

[0043] In this aspect, the second layer 32 may contain MgO. Since MgO has a lattice constant close to that of TiN or Cu, when the second layer 32 contains MgO, the stress due to lattice constant mismatch can be relaxed, and the bonding strength between the metal member 10 and the ceramic member 20 can be improved.

[0044] In this embodiment, the second layer 32 may further contain a silicide or aluminide of an active metal element. If the ceramic member 20 is made of Si3N4, the second layer 32 may contain a silicide of an active metal element such as Ti5Si3, and if the ceramic member 20 is made of AlN, the second layer 32 may contain an aluminide of an active metal element such as TiAl. Below, as an example, the case in which the second layer 32 contains Ti5Si3 will be described. The silicide or aluminide of an active metal element such as Ti5Si3 may be present in the region of the second layer 32 from the interface with the first layer 31 to 60% of the thickness Tx of the second layer 32.

[0045] In the second layer 32, it is preferable that MgO is not substantially dispersed in Ti5Si3 (i.e., in the silide or aluminide of the active metal element). In this specification, "substantially dispersed MgO" may include not only cases where no MgO is dispersed at all in the target region, but also cases where only a trace amount of MgO (for example, less than 5% of the total MgO content in the second layer 32) is dispersed. Furthermore, it is preferable that the nitride crystal X described above is also not substantially dispersed in Ti5Si3 (i.e., in the silide or aluminide of the active metal element).

[0046] The second layer 32 may further contain a Cu phase. When the second layer 32 contains a Cu phase, it is preferable that at least a portion of the MgO in the second layer 32 is dispersed (dispersed in island-like manner) within the Cu phase. Since MgO has a lattice constant close to that of Cu, the dispersion of MgO within the Cu phase can efficiently improve the bonding strength between the metal member 10 and the ceramic member 20. The Cu phase of the second layer 32 may consist of pure Cu, or, similar to the solid solution phase 31A of the first layer 31, it may be a phase mainly composed of a solid solution in which Mg is solid-dissolved in Cu crystals.

[0047] Nitrides of active metal elements, such as TiN, may be dispersed (dispersed in island-like formations) near the interface between the first layer 31 and the second layer 32. The TiN present near the interface between the first layer 31 and the second layer 32 may be dispersed, for example, with a diameter of 1 to 30 nm and spacing of 50 to 300 nm. Since TiN may be accompanied by MgO, it can alleviate stress caused by lattice constant mismatch between the Cu of the first layer 31 and TiN, thereby further improving the bonding strength between the metal member 10 and the ceramic member 20.

[0048] By possessing these various features, this embodiment successfully achieves a significant improvement in the bonding strength and thermal cycle reliability between the metal member 10 and the ceramic member 20.

[0049] Specifically, the shear strength of the bonding layer 30 in this embodiment is 10 MPa or more, preferably 40 MPa or more. Furthermore, the tensile strength of the bonding layer 30 in this embodiment is 17.3 MPa or more, preferably 86.6 MPa or more.

[0050] The shear strength of the bonding layer 30, as used herein, refers to the magnitude of shear stress per unit area required to cause the bonding layer 30 to fracture (shear failure) when stress (shear stress) is applied to the bonding layer 30 in such a way that the metal member 10 and the ceramic member 20 are displaced in opposite directions along directions parallel to the bonding surfaces 10s and 20s, as shown in Figure 5(a). The tensile strength of the bonding layer 30, as shown in Figure 5(b), refers to the magnitude of tensile stress per unit area required to cause the bonding layer 30 to fracture (peel failure) when stress (tensile stress) is applied to the bonding layer 30 in such a way that the metal member 10 and the ceramic member 20 are pulled apart along directions perpendicular to the bonding surfaces 10s and 20s.

[0051] Furthermore, the metal / ceramic joint 100 in this application has high thermal cycling reliability. Specifically, for example, when a 200-cycle of -50°C for 30 minutes and 150°C for 30 minutes was performed, no cracking of the ceramic member 20 and no delamination of the metal member 10 were observed, demonstrating high thermal cycling reliability. The presence or absence of cracking of the ceramic member 20 and delamination of the metal member 10 can be confirmed, for example, by ultrasonic testing (SAT).

[0052] (2) Method for manufacturing metal / ceramic joints Next, the manufacturing method for the metal / ceramic joint 100 described above will be explained using Figures 6(a) to 6(c).

[0053] First, as shown in Figure 6(a), the metal member 10 and the ceramic member 20 described above are arranged to be laminated together via the brazing material 50.

[0054] As mentioned above, the brazing material 50 is a Cu-Mg type brazing material that does not contain Ag. For example, a material can be used that contains 50-80 at% Cu, 5-20 at% Mg, and a total of 0.1-10 at% of the active metal element (Ti in this case).

[0055] The Cu contained in the brazing material 50 acts to cause the various characteristics described above to manifest in the bonding layer 30 formed by the reaction of the brazing material 50 with the metal member 10 and the ceramic member 20. In addition, the Mg contained in the brazing material 50 acts to improve the wettability between the metal member 10 and the brazing material 50, and between the ceramic member 20 and the brazing material 50, in a balanced manner when bonding the metal member 10 and the ceramic member 20. Furthermore, the active metal elements contained in the brazing material 50 react with the ceramic member 20 to form a second layer 32, and act to increase the bonding strength between the bonding layer 30 and the ceramic member 20.

[0056] Furthermore, if the Mg content in the brazing material 50 falls below 5 at%, or the active metal element content falls below 0.1 at%, and the Cu content exceeds 80 at%, the effects of Mg addition and the effects of active metal element addition described above may not be obtained.

[0057] Furthermore, if the Mg content in the brazing material 50 exceeds 20 at%, or if the total active metal element content exceeds 10 at%, and the Cu content falls below 50 at%, the effects of adding Cu as described above may not be obtained.

[0058] In the brazing material 50, Cu can be included in at least one of the following forms: elemental (pure Cu), hydride (CuH), intermetallic compound with Mg (MgCu2), or intermetallic compound with an active metal element (e.g., Cu-Ti compound). If the active metal element is selected, for example, Ti can be included in at least one of the following forms: elemental (pure Ti), hydride (TiH2), intermetallic compound with Cu, or intermetallic compound with Mg.

[0059] In the brazing material 50 for this purpose, Mg must be present in the form of an oxide (MgO) at least a portion of it. For example, it is preferable that 10 to 50 at% of the Mg contained in the brazing material 50 is present in the form of MgO. This allows for the formation of a non-layered MgO phase 33 during bonding. In addition to MgO, the Mg contained in the brazing material 50 may also be present in the form of elemental Mg (pure Mg), hydride (MgH2), intermetallic compounds with Cu (MgCu2), or compounds with active metal elements (e.g., Mg-Ti compounds). Specifically, for example, by pre-treating elemental Mg with surface oxidation, Mg whose surface is covered with MgO can be included in the brazing material 50.

[0060] In the brazing material 50, Cu and Mg must be included either as individual elements or as an alloy containing Cu and Mg, with reduced particle size (for example, with an average particle size (D50) of 45 μm or less). This increases the surface area and facilitates oxygen incorporation, allowing for the formation of a non-layered MgO phase 33. The lower limit of the average particle size of Cu and Mg is not particularly limited, but for example, it is 5 μm or more. The average particle size can be measured by a laser diffraction particle size distribution analyzer. In this specification, D50 is considered to be the average particle size.

[0061] The brazing material 50 needs to be heat-treated (hydrogen reduction treatment) in a 100% hydrogen atmosphere or a non-oxidizing (inert) atmosphere containing 3 vol.% or more of hydrogen before joining. By applying hydrogen reduction treatment to the brazing material 50, the proportion of MgO in the brazing material 50 can be increased. This makes it easier for a non-layered MgO phase 33 to be formed during joining.

[0062] The brazing material 50 may be in the form of a powder, foil, or paste. From the viewpoint of facilitating the formation of the MgO phase 33 as shown in Figure 2, it is preferable to use a powder or paste. In the case of a paste, alcohols such as terpineol and butanediol, or toluenes, may be used as the main solvent; polyvinyl alcohol, ethylcellulose, polymethacrylic acid, polyacrylic, etc., may be used as the binder; and cationic, anionic, or nonionic surfactants may be used. Plasticizers and dispersants may also be included.

[0063] As a method for placing the brazing material 50 on the planned joining surfaces 10s' and 20s' between the metal member 10 and the ceramic member 20, known methods such as screen printing, transfer, dispensing, inkjet, spray coating, sputtering, and vapor deposition can be used.

[0064] Next, as shown in Figure 6(b), the laminate 100' of the metal member 10 and ceramic member 20, which are arranged via the brazing material 50, is heated and held in a predetermined atmosphere while being pressurized in the lamination direction. The predetermined atmosphere can be any of the following: a vacuum atmosphere (reduced pressure atmosphere), an inert gas atmosphere, or a reducing atmosphere. By introducing an inert gas such as nitrogen (N2), the oxygen concentration can be adjusted. Furthermore, when the MgO phase 33 is formed, oxygen is removed from around the laminate 100', making it difficult for Cu, Ti, etc. to oxidize, and thus high bonding strength can be maintained.

[0065] The heating temperature during joining should, for example, be above the melting point of the brazing material 50 and below the melting point of the metal member 10. Preferably, it should be 115% or less of the melting point (absolute temperature) of the brazing material 50, and more preferably 101% to 110% of the melting point (absolute temperature) of the brazing material 50. This improves the diffusivity of the active metal elements and facilitates the formation of the second layer 32. When using the brazing material 50 for this purpose, for example, it is preferable to set the heating temperature to 735°C to 900°C. Known furnaces such as static batch furnaces, multi-chamber furnaces, and belt conveyor furnaces can be used as the heat treatment furnace for joining.

[0066] Other conditions during joining include the following: Oxygen concentration: 0.01 ppm to 1000 ppm Pressurization: 0.5kPa or higher Retention time: There are no specific restrictions, but for example, 3 minutes to 120 minutes.

[0067] During heating, it is necessary for a liquid phase to be formed in a portion of the brazing material 50, and in addition, the active metal element must be molten in that liquid phase. This state can be created by heating the material to a temperature of 735°C or higher. However, if the heating temperature is too high, the evaporation of Mg will be severe, making it difficult to form the liquid phase, or voids may be generated in the formed bonding layer 30. These problems can be avoided by heating the material to a temperature of 900°C or lower. By applying pressure of 0.5 kPa or higher, the adhesion between the metal member 10 and the ceramic member 20 via the brazing material 50 can be maintained, and the bonding strength between the metal member 10 and the ceramic member 20 can be increased. There is no particular upper limit to the pressure, but for example, it can be set to around 20 kPa.

[0068] Subsequently, the heated laminate 100' is cooled. As a result, a metal / ceramics bond 100 having the various characteristics described above is manufactured, as shown in Figure 6(c).

[0069] Furthermore, when the metal / ceramic bond 100 is used as an insulating circuit board, etching may be performed after placing an etching resist on the metal member 10 in order to form a circuit pattern on the metal member 10. The type of etching resist is not particularly limited, and for example, known thermosetting or ultraviolet curing resists can be used. The method of placing the etching resist is also not particularly limited, and methods such as placing a film-like resist film, screen printing, or inkjet coating can be employed. In addition, after removing the unnecessary parts of the metal member 10 from the metal / ceramic bond 100 by etching, the bonding layer 30 of any further unnecessary parts may be removed.

[0070] (3) Effects According to this embodiment, one or more of the following effects can be obtained.

[0071] (a) In this configuration, the bonding layer 30 (first layer 31) contains a non-layered MgO phase 33 containing magnesium oxide (MgO). The presence of the non-layered MgO phase 33 in the bonding layer 30 (especially the first layer 31) mitigates the generation of thermal stress caused by the difference in thermal expansion coefficients between the metal member 10 and the ceramic member 20, thereby improving bonding strength and thermal cycle reliability.

[0072] (b) In this configuration, it is preferable that the MgO phase 33 surrounds at least one of the solid solution phase 31A and the compound phase 31B. The presence of the MgO phase 33 in this manner can mitigate the generation of thermal stress between the solid solution phase 31A and the compound phase 31B, thereby further improving the bonding strength and thermal cycle reliability.

[0073] (c) In the present invention, it is preferable that the region surrounded by the MgO phase 33 has a solid solution phase 31A proportion of 90% or more, or a compound phase 31B proportion of 90% or more. This means that the MgO phase 33 is abundant at the boundary between the solid solution phase 31A and the compound phase 31B. The presence of the MgO phase 33 in this manner can mitigate the generation of thermal stress between the solid solution phase 31A and the compound phase 31B, thereby further improving the bonding strength and thermal cycle reliability.

[0074] (d) In this configuration, the bonding strength between the metal member 10 and the ceramic member 20 can be dramatically increased. For example, the shear strength of the bonding layer 30 can be set to 10 MPa or more, preferably 40 MPa or more. In addition, the tensile strength of the bonding layer 30 can be set to 17.3 MPa or more, preferably 86.6 MPa or more.

[0075] (e) In this application, the thermal cycle reliability of the metal / ceramics joint 100 can be dramatically improved. For example, when a 200-cycle cold cycle of -50°C for 30 minutes and 150°C for 30 minutes is performed, no cracking of the ceramic member 20 and no delamination of the metal member 10 can be observed, demonstrating high thermal cycle reliability.

[0076] <Other aspects of this disclosure> The aspects of this disclosure have been described in detail above. However, this disclosure is not limited to the aspects described above and can be modified in various ways without departing from its essence.

[0077] The metal / ceramic bond 100 in this embodiment is not limited to applications as an insulating circuit board, but can be widely applied to various applications such as heat sinks and components of internal combustion engines and power generation machines, and in these cases as well, the same effects as in the embodiment described above can be obtained. [Examples]

[0078] (Preparation of samples 1-38) For the ceramic components, a 50mm × 50mm × 0.32mm Si3N4 substrate, a 50mm × 50mm × 0.635mm AlN substrate, and a 50mm × 50mm × 0.635mm Al2O3 substrate were prepared. For the metal components, a 48mm × 48mm × 0.8mm Cu plate was prepared for the Si3N4 substrate, and a 48mm × 48mm × 0.3mm Cu plate was prepared for the AlN and Al2O3 substrates. As the brazing material, a paste made by mixing Cu, Mg, and Ti in predetermined ratios was used. For Cu and Mg, powders with an average particle size of 45 μm or less were used. For Mg, a surface oxidation treatment was performed beforehand to make the surface MgO. For paste formation, polyethylene glycol and diethylene glycol monobutyl ether with a molecular weight of 400 or less were used as solvents, and the ratio of solvent in the paste was 9 mass%. The elemental mixing ratio (by weight) of Cu:Mg:Ti in the paste was as shown in Tables 1-3. This paste was applied to the intended bonding surface of the ceramic members using screen printing, and the metal members were placed directly on top of the applied paste film. Hydrogen reduction treatment was then performed in a 100% hydrogen atmosphere. Subsequently, samples 1-36 were prepared by applying pressure of 8 kPa along the lamination direction and performing heat treatment for 60 minutes at the predetermined bonding temperature shown in Tables 1-3 in a vacuum atmosphere.

[0079] Sample 37 was prepared under the same conditions as Sample 1, except that Cu and Mg powders with an average particle size of approximately 100 μm were used as raw materials for the brazing material, and no surface oxidation treatment of the Mg or hydrogen reduction treatment of the brazing material was performed.

[0080] For sample 38, instead of using Cu as the raw material for the wax, a paste made by mixing Mg and Ti powders in an elemental mixing ratio of 97:3 was used. All other conditions were the same as for sample 29.

[0081] (Presence and form of the MgO phase) The presence and form of the MgO phase in the bonding layer (first layer) were determined by observation and analysis of the cross-section of the bonded body using scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). Samples for SEM observation were obtained by cutting out arbitrary pieces of approximately 10 mm × 10 mm from the obtained metal / ceramic bonded body, embedding them in resin, and polishing the cross-section of the bonded body. STEM observation samples were processed using focused ion beam (FIB) to include regions where the MgO phase was thought to exist within the bonding layer. Using STEM, a 5 μm × 5 μm area was observed at an acceleration voltage of 200 kV and a magnification of 400,000x. The spectrum was analyzed using electron energy loss spectroscopy (EELS). If a peak as shown in Figure 4 was observed, and it was determined that a non-layered MgO phase was formed, it was indicated with a "○" in Tables 1-3. If the peak was not observed, it was determined that the MgO phase was not formed, and it was indicated with a "×" in Tables 1-3.

[0082] (Joint strength test) Shear strength tests were performed on the resulting metal / ceramic joints (samples 1-38). For this test, samples 1-38 were first prepared by processing the metal members into cylindrical shapes with a diameter of 3 mm and a height of 2 mm, exposing the bonding surface of the surrounding ceramic members. Then, as shown in Figure 8, with the ceramic members of the test specimens fixed, the cylindrical metal members were pressed using a displacement jig in a direction parallel to the bonding surface. The magnitude of the stress at which the bonding layer fractured (shear failure) was measured, and the degree of shear strength of the bonding layer was calculated based on this value. The shear test position (contact height H of the displacement jig) was set at a height of 200 μm from the exposed surface of the ceramic member, and the displacement axis movement speed was set to 100 μm / s. Tensile strength was also calculated from the obtained shear strength, and the values ​​of shear strength and tensile strength are shown in Tables 1-3.

[0083] (Reliability testing) Thermal cycling tests were performed on the obtained metal / ceramic joints (samples 1-38). The test conditions consisted of 200 cycles of cold cycling at -50°C for 30 minutes and 150°C for 30 minutes. Every 50 cycles, ultrasonic testing (SAT) was performed to determine whether there were any cracks in the ceramic component or delamination in the metal component. If no cracks in the ceramic component or delamination in the metal component was found, it was indicated with "○" in Tables 1-3. If partial cracks in the ceramic component or partial delamination in the metal component were found, it was indicated with "△" in Tables 1-3. If large cracks in the ceramic component or large delamination in the metal component were found, it was indicated with "×" in Tables 1-3.

[0084] [Table 1]

[0085] [Table 2]

[0086] [Table 3]

[0087] As shown in Tables 1-3, samples 1-36, in which a non-layered MgO phase was formed in the bonding layer (first layer), showed high bonding strength, and no cracking of the ceramic component or delamination of the metal component was observed during thermal cycling tests. On the other hand, sample 37, in which no MgO phase was formed in the bonding layer (first layer), showed somewhat lower bonding strength, and partial cracking of the ceramic component and partial delamination of the metal component were observed during thermal cycling tests. Furthermore, sample 38, in which Cu was not used as the raw material for the brazing material, showed very low bonding strength and low thermal cycling reliability. From the above, it was confirmed that forming a non-layered MgO phase in the bonding layer (first layer) can yield a metal / ceramic bond with high bonding strength and high thermal cycling reliability.

[0088] <Preferred aspects of this disclosure> Preferred embodiments of this disclosure are described below. These embodiments can be combined with each other.

[0089] According to one aspect of this disclosure, Metal components and A ceramic member joined to the aforementioned metal member, A bonding layer is formed on the bonding surface between the metal member and the ceramic member, and further comprises Cu and Mg, and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er. A metal / ceramics bond is provided, in which a non-layered MgO phase containing MgO is present in the bonding layer.

[0090] Preferably, The aforementioned bonding layer is A first layer comprising a solid solution phase in which Mg is solidly dissolved in Cu, and a compound phase having an intermetallic compound containing Cu and Mg, which constitutes the interface with the metal member, It has a second layer that forms an interface with the ceramic member, contains a compound of the active metal element, and is in contact with the first layer, The first layer contains the non-layered MgO phase.

[0091] Preferably, The MgO phase exists so as to surround at least one of the solid solution phase and the compound phase.

[0092] Preferably, Within the region surrounded by the MgO phase, the proportion of the solid solution phase is 90% or more, or the proportion of the compound phase is 90% or more.

[0093] Preferably, In the cross-section of the first layer, the area ratio of the MgO phase is 5% or more and 15% or less.

[0094] Preferably, Cross-section of the first layer: 500 μm 2 When the area fraction of the MgO phase in the region is measured multiple times in different observation fields, the difference between the maximum and minimum values ​​of the area fraction of the MgO phase is within 5%.

[0095] Preferably, The electron energy loss spectrum of the aforementioned MgO phase, analyzed by scanning transmission electron microscopy, shows peaks in the ranges of 50-80 eV and 530-560 eV, respectively.

[0096] Preferably, The bonding layer contains 50-80 at% Cu, 5-20 at% Mg, and a total of 0.1-10 at% of the active metal elements.

[0097] Preferably, When the first layer is observed in a cross-section perpendicular to the bonding surface, the number of voids with an equivalent circular diameter of 8 μm or larger is 10,000 μm. 2 There is less than one per person.

[0098] Preferably, When a cooling cycle of -50°C for 30 minutes and 150°C for 30 minutes was performed 200 times, no cracking of the ceramic component and no delamination of the metal component were observed.

[0099] According to other aspects of this disclosure, Used for joining metal components and ceramic components, It contains 50-80 at% Cu, 5-20 at% Mg, and a total of 0.1-10 at% of at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er. The aforementioned Mg is present in at least a portion in the form of MgO, A brazing material is provided in which the Cu and Mg are contained in a state where the average particle size is 45 μm or less.

[0100] According to yet another aspect of this disclosure, A process of arranging a metal component and a ceramic component so as to be laminated with a brazing material in between, The process includes heating and holding the laminate of the metal member and the ceramic member while applying pressure in the lamination direction, A method for manufacturing a metal / ceramics bond is provided, in which the brazing material contains 50-80 at% Cu, 5-20 at% Mg, and a total of 0.1-10 at% of at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, and at least a portion of the Mg is contained in the form of MgO, and the Cu and Mg are contained in a state in which the average particle size is 45 μm or less, and the brazing material is subjected to a hydrogen reduction treatment.

[0101] According to yet another aspect of this disclosure, A method for manufacturing brazing material used for joining metal members and ceramic members, The mixture contains 50-80 at% Cu, 5-20 at% Mg, and a total of 0.1-10 at% of at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er. The aforementioned Mg contains at least a portion in the form of MgO, A method for producing a brazing material is provided, in which the Cu and Mg used are powders with an average particle size of 45 μm or less.

[0102] Preferably, The aforementioned Mg is made by subjecting it to a surface oxidation treatment, which results in a surface containing MgO. [Explanation of symbols]

[0103] 100 Metal / Ceramic Joints 100' laminate 10 Metal components 10s joint surface 20 Ceramic components 20s joint surface 30 Bonding layer 31 1st layer 31A Solid solution phase 31B Compound phase 32 2nd layer 33 MgO phase 34S void (equivalent circle diameter less than 8 μm) 34L void (equivalent diameter of circle 8μm or larger) 50 Brazing material

Claims

1. Metal components and A ceramic member joined to the aforementioned metal member, The bonding surface between the metal member and the ceramic member comprises a bonding layer formed thereon, which contains Cu and Mg, and further contains at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er. A metal / ceramic bond in which a non-layered MgO phase containing MgO is dispersed in both the thickness direction and the creepage direction of the bonding layer in a cross-section including the metal member, the ceramic member, and the bonding layer, and exists in a curved, elongated form.

2. The aforementioned bonding layer is A first layer comprising a solid solution phase in which Mg is solidly dissolved in Cu crystals, and a compound phase having an intermetallic compound containing Cu and Mg, which constitutes the interface with the metal member, It has a second layer that forms an interface with the ceramic member, contains a compound of the active metal element, and is in contact with the first layer, The metal / ceramics bond according to claim 1, wherein the MgO phase is present in the first layer.

3. The metal / ceramics bond according to Claim 1, wherein the thickness of the MgO phase is 10 nm or more and 1 μm or less.

4. The metal / ceramics bond according to claim 2, wherein the MgO phase exists so as to surround at least one of the solid solution phase and the compound phase.

5. The metal / ceramics bond according to claim 4, wherein the diameter of the region surrounded by the MgO phase is 1 μm or more and 20 μm or less.

6. The metal / ceramics bond according to claim 1, wherein the MgO phase is dispersed such that the shear strength of the bonded layer is 10 MPa or more and the tensile strength of the bonded layer is 17.3 MPa or more.

7. The metal / ceramics bond according to claim 4, wherein the region surrounded by the MgO phase has a solid solution phase proportion of 90% or more, or a compound phase proportion of 90% or more.

8. The metal / ceramics bond according to claim 2, wherein in the cross-section of the first layer, the area ratio of the MgO phase is 5% or more and 15% or less.

9. Cross-section of the first layer: 500 μm ２ The metal / ceramics bond according to claim 2, wherein when the area ratio of the MgO phase in the region is measured multiple times in different observation fields, the difference between the maximum and minimum values ​​of the area ratio of the MgO phase is within 5%.

10. The metal / ceramic bond according to claim 1, wherein the electron energy loss spectrum of the MgO phase, as analyzed by a scanning transmission electron microscope, has peaks in the ranges of 50 to 80 eV and 530 to 560 eV, respectively.

11. The metal / ceramic bonded body according to claim 1, wherein the bonding layer contains 50 to 80 at% Cu, 5 to 20 at% Mg, and a total of 0.1 to 10 at% of the active metal elements.

12. When the first layer is observed in a cross-section perpendicular to the bonding surface, the number of voids with an equivalent circular diameter of 8 μm or larger is 10,000 μm. ２ The metal / ceramic bond according to claim 2, wherein there is less than one per unit.

13. The metal / ceramic joint according to claim 1, wherein no cracking of the ceramic member and delamination of the metal member are observed when a cooling cycle of -50°C for 30 minutes and 150°C for 30 minutes is performed 200 times.

14. Used for joining metal components and ceramic components, It contains 50-80 at% Cu, 5-20 at% Mg, and a total of 0.1-10 at% of at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er. The aforementioned Mg is included in an embodiment in which at least a portion is MgO. The brazing material contains Cu and Mg in a state where the average particle size is 45 μm or less.

15. A process of arranging a metal component and a ceramic component so as to be laminated with a brazing material in between, A step of applying a hydrogen reduction treatment to the arranged brazing material, The process includes a step of heating and holding a laminate in which the metal member and the ceramic member are laminated via the brazing material that has undergone the hydrogen reduction treatment, while applying pressure in the lamination direction. A method for manufacturing a metal / ceramics bond, using a material as the brazing material that contains 50 to 80 at% Cu, 5 to 20 at% Mg, and a total of 0.1 to 10 at% of at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, wherein at least a portion of the Mg is contained in the form of MgO, and the Cu and Mg are contained in a state in which the average particle size is 45 μm or less.

16. A method for manufacturing brazing material used for joining metal members and ceramic members, The mixture contains 50-80 at% Cu, 5-20 at% Mg, and a total of 0.1-10 at% of at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Y, Ce, La, Sm, Yb, Nd, Gd, and Er. The aforementioned Mg is provided in an embodiment that includes at least a portion of MgO. A method for producing a brazing material, wherein the Cu and Mg are powders with an average particle size of 45 μm or less.

17. The method for producing a brazing material according to claim 16, wherein the Mg is subjected to a surface oxidation treatment to make the surface MgO.

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