Joint, manufacturing method thereof, and electrode-embedded member

Abstract

To provide: a bonded body capable of suppressing erosion and contamination of a bonded surface, strong in joint strength, and thick in the thickness of a metal member; a method for producing the same; and an electrode-embedded member.SOLUTION: A ceramic member 20 is bonded to at least one major surface of a metal member 30; a metal member 30 has a maximum thickness of 1 mm or more in a direction perpendicular to one of a main surfaces of the metal member 30; when a reference line segment of 200 μm in length is taken on a ceramic member side of a cross-sectional curve of a bonding interface between the ceramic member 20 and the metal member 30, the line segment not intersecting the cross-sectional curve side but making contact at two or more locations, and a second line segment of 200 μm in length is taken on a metal member side of the cross-sectional curve, the line segment not intersecting the cross-sectional curve but making contact and being an opposite side of a rectangle to the reference line segment, a distance between the reference line segment and the second line segment is 6.0 μm or more; and an oxygen concentration of a ceramic member 20 inside the reference line segment and the second line segment is higher than that of the ceramic member 20 outside the reference line segment.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a bonded body, a method for producing the same, and an electrode-embedding member. [Background technology]

[0002] AlN components used in semiconductor manufacturing equipment are sometimes joined to metal components to add various functions.

[0003] Patent Document 1 discloses a bonded assembly in which an aluminum nitride member and a metal member are bonded with an aluminum brazing material, and a semiconductor holder. A preferred embodiment is disclosed in which the aluminum nitride member is a semiconductor holder having a mounting surface for mounting a semiconductor wafer, and the metal member is a heat transfer member for transferring heat between the semiconductor holder and the outside. The document also discloses examples of heat transfer members made of tungsten, molybdenum, copper, or alloys thereof. These metal members function as heat sinks and have a certain thickness.

[0004] Furthermore, Patent Document 2 discloses an aluminum nitride joined body having a relatively thick and highly conductive sintered metal layer incorporated therein, which minimizes warpage and has a high bonding strength between the sintered metal layer and the substrate, and is suitable for use as an electrode-embedded member, and a method for manufacturing the same. The aluminum nitride joined body has an aluminum nitride sintered body having a sintered metal layer made of tungsten or molybdenum and having a thickness of 15 to 100 μm formed on at least a portion of the bonding surface, and the sheet resistance of the sintered metal layer is 1 Ω / □ or less and the warpage of the sintered metal layer is 100 μm / 100 mm or less, with the aim of providing such an aluminum nitride joined body and a method for manufacturing the same. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-249465 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-159334 [Patent Document 3] Japanese Patent Application Publication No. 5-246769 [Patent Document 4] Japanese Patent Application Publication No. 62-78167 [Non-patent literature]

[0006] [Non-Patent Document 1] Journal of the Japan Institute of Metals, Vol. 45, No. 2 (1981), pp. 184-189 Summary of the Invention [Problem to be solved by the invention]

[0007] AlN ceramics used in semiconductor manufacturing processes are sometimes integrated with high-melting-point metals used in heat sinks, etc. To do this, the high-melting-point metal needs to be thicker than a certain amount, but such a structure cannot be achieved with a sintered metal layer such as that described in Patent Document 2.

[0008] According to Non-Patent Document 1, it has been said that it is difficult to produce a bonded body because AlN and high-melting-point metals do not react without a bonding material. Therefore, conventionally, a bonded body of AlN ceramic and high-melting-point metal has been produced by joining them with a brazing material or the like at the bonding interface (Patent Documents 1, 3, and 4).

[0009] However, when these bonded bodies are used in semiconductor manufacturing processes, there are concerns about erosion of the brazing material that forms the bonding layer and contamination from the bonding layer in the methods of Patent Documents 1, 3, and 4. Therefore, there has been a demand for an AlN-high melting point metal bonded body that is a bonded body of AlN ceramic and a thick high melting point metal and that suppresses the risk of contamination and erosion from the bonding material.

[0010] The present invention has been made in view of the above circumstances, and aims to provide a bonded body that can suppress erosion and contamination of the bonding surface, has high bonding strength, and has thick metal members, a manufacturing method thereof, and an electrode-embedded member. [Means for solving the problem]

[0011] (1) In order to achieve the above object, the present invention provides a joined body of a ceramic member mainly composed of AlN and a metal member made of a high-melting-point metal having a melting point of 2000°C or higher, wherein the ceramic member is joined to at least one main surface of the metal member, the metal member has a maximum thickness of 1 mm or more in a direction perpendicular to one main surface of the metal member, and in a 500x microscope image of a cross section perpendicular to one main surface of the metal member, the cross section of a cross section curve of a joining interface between the ceramic member and the metal member is 1 mm or more. When a reference line segment having a length of 200 μm is drawn on the ceramic member side, contacting the cross-sectional curve at two or more points without intersecting the cross-sectional curve, and a second line segment having a length of 200 μm is drawn on the metal member side of the cross-sectional curve, contacting the cross-sectional curve without intersecting the cross-sectional curve and forming the opposite side of a rectangle with respect to the reference line segment, the distance between the reference line segment and the second line segment is 6.0 μm or more, and the oxygen concentration of the ceramic member inside the reference line segment and the second line segment is higher than the oxygen concentration of the ceramic member outside the reference line segment.

[0012] In this way, in a 500x microscope image of a cross section perpendicular to one of the main surfaces of the metal member, a 200 μm-long reference line segment is drawn on the ceramic member side of the cross-sectional curve of the bonding interface between the ceramic member and the metal member, contacting the cross-sectional curve at two or more points without intersecting the cross-sectional curve, and a 200 μm-long second line segment is drawn on the metal member side of the cross-sectional curve, contacting the cross-sectional curve without intersecting the cross-sectional curve, and forming the opposite side of a rectangle relative to the reference line segment. The distance between the reference line segment and the second line segment is 6.0 μm or more. In other words, the cross-sectional curve of the bonding interface between the ceramic member and the metal member has an unevenness of 6.0 μm or more every 200 μm. By increasing the oxygen concentration of the convex parts of the ceramic member compared to the oxygen concentration of the rest of the ceramic member, the bonding strength between the AlN ceramic and the metal member can be strengthened and a bonded structure with reduced erosion and contamination at the bonding surface can be obtained. Furthermore, the thick metal member can be used for various purposes, such as using the metal member as a heat sink or improving the strength and dimensional accuracy of the bonded structure.

[0013] (2) In the joined body of the present invention, the ceramic member contains a second phase made of a metal oxide.

[0014] In this way, by including a second phase made of a metal oxide in the ceramic member, it is possible to change the properties of the AlN ceramic while maintaining the bonding strength, thereby broadening the range of uses for the bonded body.

[0015] (3) In the joined body of the present invention, the metal member contains 1 wt % or less of a second metal oxide.

[0016] In this way, when the metal member contains 1 wt % or less of the second metal oxide, the bonding strength between the AlN ceramic and the metal member is increased, and the reliability of the bonded body is improved.

[0017] (4) In the joined body of the present invention, the ceramic member contains a metal of Group 4 of the periodic table.

[0018] In this way, by including a metal from Group 4 of the periodic table in the ceramic member, it is possible to change the properties of the AlN ceramic while maintaining the bonding strength, thereby broadening the range of uses for the bonded body.

[0019] (5) In the joined body of the present invention, the metal members may have a through hole penetrating in the thickness direction, or a groove on one of the main surfaces or on the other main surface opposite to the one of the main surfaces.

[0020] In this way, by providing the metal member with a through-hole penetrating in the thickness direction or a groove on one or the other of the main surfaces, the range of uses of the bonded body is further expanded.

[0021] (6) The joined body of the present invention is characterized in that a ceramic member is further joined to the other main surface of the metal member opposite to the one main surface of the metal member.

[0022] In this way, by bonding AlN ceramics to both main surfaces of the metal member, the range of uses of the bonded body is further expanded.

[0023] (7) Furthermore, the present invention provides an electrode-embedding member comprising the joined body according to any one of (1) to (5) above, and an electrode embedded in a ceramic member of the joined body.

[0024] Since AlN has high thermal conductivity and high insulating properties, an electrode-embedded member in which electrodes are embedded in AlN ceramics of a bonded body of AlN ceramics and metal members can be used as a heater module.

[0025] (8) A method for producing a joined body of the present invention is a method for producing a joined body of ceramic members mainly composed of AlN and metal members made of a high-melting-point metal having a melting point of 2000°C or higher, and includes the steps of: preparing a granulated powder obtained by granulating AlN raw material powder or a powder obtained by adding a metal oxide raw material powder to the AlN raw material powder; preparing a metal member precursor that is made of the high-melting-point metal in a plate shape, has a maximum thickness of 1 mm or more in a direction perpendicular to one main surface, and is roughened so that the one main surface has an unevenness of 6.0 μm or more per reference line segment having a length of 200 μm; stacking the granulated powder or a compact formed from the granulated powder and the metal member precursor on a carbon mold so that the one main surface of the metal member precursor is perpendicular to a stacking direction; inserting a carbon punch into the carbon mold to form a stack; and uniaxially pressurizing and firing the stack, wherein the uniaxially pressurizing and firing step is By uniaxial pressure firing at 1800°C for 2 hours or more, or at 900°C to 1500°C for 5 hours or more, The granulated powder or the compact penetrates into the recesses on the one main surface of the metal member precursor, and the oxygen concentration of the ceramic member that has penetrated into the recesses and been fired is controlled to be higher than the oxygen concentration of the ceramic member that has been fired outside the recesses.

[0026] This results in a bonded assembly of AlN ceramics and metal members made of high-melting-point metals with high bonding strength and reduced erosion and contamination on the bonding surfaces. The thick metal member can be used for a variety of purposes, such as using the metal member as a heat sink or improving the strength and dimensional accuracy of the AlN ceramics.

[0027] (9) In the method for producing a joined body of the present invention, the metal member precursor may have a through hole penetrating in a thickness direction, or a groove on the one main surface or the other main surface opposite to the one main surface.

[0028] In this way, by using a metal member precursor having through holes penetrating in the thickness direction or grooves on one or the other of its main surfaces, it is possible to process a difficult-to-process high-melting-point metal in advance, and to create shapes for various structures more easily than by processing the metal after firing, further expanding the uses of the joined body. [Effects of the Invention]

[0029] According to the present invention, a bonded body can be obtained in which erosion and contamination of the bonding surface between a ceramic member mainly composed of AlN and a metal member made of a high-melting-point metal is suppressed. Furthermore, the thick metal member can be used for various purposes, such as using the metal member as a heat sink or improving the strength and dimensional accuracy of the ceramic member. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic cross-sectional view showing an example of a bonded body according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an enlarged view of a part around a cross-sectional curve in an example of a bonded body according to an embodiment of the present invention. [Figure 3] FIG. 10 is a schematic cross-sectional view showing a modified example of the bonded body according to the embodiment of the present invention. [Figure 4] 1 is a schematic cross-sectional view showing an example of an electrode-embedded member according to an embodiment of the present invention. [Figure 5]1(a) to 1(e) are cross-sectional views each showing a schematic diagram of a step in the manufacturing process of a manufacturing method according to an embodiment of the present invention. [Figure 6] 1(a) to 1(e) are cross-sectional views each showing a schematic diagram of a step in the manufacturing process of a manufacturing method according to an embodiment of the present invention. [Figure 7] (a) is an SEM image of a cross section of Example 1. (b) to (g) are photographs showing mapping of EPMA analysis of the cross section of Example 1, respectively. [Figure 8] 1(a) and 1(b) are SEM images of the cross sections of Example 1 and Comparative Example 1, respectively, taken at 2000x magnification. DETAILED DESCRIPTION OF THE INVENTION

[0031] Next, an embodiment of the present invention will be described with reference to the drawings. To facilitate understanding of the description, the same reference numerals are used to designate the same components in the drawings, and duplicated descriptions will be omitted. Note that in the configuration diagrams, the size of each component is shown conceptually and does not necessarily represent the actual dimensional ratio.

[0032] [Embodiment] [Construction of the zygote] First, a bonded body according to an embodiment of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing an example of a bonded body according to an embodiment of the present invention. A bonded body 10 according to an embodiment of the present invention is formed by bonding a ceramic member 20 primarily composed of AlN and a metal member 30 composed of a high-melting-point metal. A ceramic member primarily composed of AlN refers to a member containing 90 wt% or more of AlN. A metal member composed of a high-melting-point metal refers to a member having a purity of 99 wt% or more, such as molybdenum (Mo), tungsten (W), or tantalum (Ta), which has a melting point of 2000°C or higher. This suppresses deformation of the metal member 30 even at temperatures during uniaxial pressure sintering. At the same time, a high-melting-point metal oxide with a relatively high melting point of 900°C or higher is formed at the interface between the AlN and the metal member 30, thereby suppressing deformation at the bonding interface between the AlN and the metal member 30.

[0033] In the joined body 10, the ceramic member 20 is joined to at least one main surface of the metal member 30. The metal member 30 preferably has a maximum diameter that is 50% or more of the maximum diameter of the ceramic member 20. The ceramic member 20 is preferably joined to the entire surface of one main surface of the metal member 30. These characteristics allow the metal member 30 to be applied in various forms according to various uses. The ceramic member 20 is preferably joined directly to one main surface of the metal member 30 without any other member interposed therebetween. This is because the joining strength may be reduced if another member is interposed therebetween.

[0034] The ceramic member 20 preferably includes a second phase made of a metal oxide. This allows the properties of the ceramic member 20 to be changed while maintaining the bonding strength, thereby broadening the range of uses of the joined body 10. When the ceramic member 20 includes a second phase made of a metal oxide, the metal constituting the metal oxide of the second phase is preferably one or more selected from Y and Ca, and more preferably Y. The metal oxide constituting the second phase may be a sintering aid for a ceramic member mainly composed of AlN. In this case, the metal oxide constituting the second phase may be added in an amount necessary as a sintering aid for the ceramic member. For example, when Y is added as a sintering aid, it may be added in an amount of 0.1 wt% to 5 wt% in terms of Y2O3. Alternatively, the ceramic member 20 may be composed solely of AlN.

[0035] Preferably, the ceramic member 20 further contains a metal of Group 4 of the periodic table. In this way, when the ceramic member 20 contains a metal of Group 4 of the periodic table, the properties of the ceramic member 20 can be changed while maintaining the bonding strength between the ceramic member 20 and the metal member 30, thereby broadening the applications of the joined body 10. The metal of Group 4 of the periodic table is preferably one or more selected from Ti and Hf, and more preferably Ti.

[0036] The metal member 30 has a maximum thickness of 1 mm or more in a direction perpendicular to one main surface 32 of the metal member 30. In this way, the metal member 30 having a large thickness can be used in a variety of applications, such as using the metal member 30 as a heat sink or heat spreader, or improving the strength and dimensional accuracy of the ceramic member 20. The one main surface 32 of the metal member 30 is the bonding surface with the ceramic member 20. The metal member 30 having a large thickness means that the maximum thickness in a direction perpendicular to the one main surface 32 of the metal member 30 is 1 mm or more. If the maximum thickness of the metal member 30 is less than 1 mm, the effect of improving dimensional accuracy will not be fully achieved, and therefore it is preferable that the maximum thickness be 1 mm or more.

[0037] The maximum thickness of the metal member 30 in the direction perpendicular to one main surface 32 is preferably set to a thickness according to the intended use. Considering that there has not been a joined body of metal members 30 with a large thickness like that of the present invention, depending on the intended use, the thickness is preferably 2 mm or more, more preferably 3 mm or more, and even more preferably 4 mm or more.

[0038] 2(a) and 2(b) are schematic partially enlarged cross-sectional views of the bonded body shown in FIG. 1 . The bonded body 10 has a distance between a reference line segment L1 and a second line segment L2 of 6.0 μm or more. The reference line segment L1 is a 200 μm long line segment that is located on the ceramic member side of the cross-sectional curve of the bonded interface between the ceramic member 20 and the metal member 30 in a 500x microscope image of a cross section perpendicular to one main surface 32 of the metal member 30, does not intersect with the cross-sectional curve, and contacts the cross-sectional curve at two or more locations. The second line segment L2 is a 200 μm long line segment that is located on the metal member side of the cross-sectional curve, does not intersect with the cross-sectional curve, and is in contact with the cross-sectional curve, forming the opposite side of a rectangle relative to the reference line segment L1.

[0039] Furthermore, the oxygen concentration of the ceramic member 20 inside the reference line segment L1 and the second line segment L2 is higher than the oxygen concentration of the ceramic member outside the reference line segment L1. That is, the oxygen concentration of the protruding portion 28 of the ceramic member is higher than the oxygen concentration of the ceramic member other than the protruding portion 28. The protruding portion 28 of the ceramic member refers to the portion of the ceramic member 20 located near the bonding interface that protrudes toward the metal member.

[0040] In this way, in a 500x microscope image of a cross section perpendicular to one main surface 32 of the metal member 30, a reference line segment L1 of 200 μm in length is taken on the ceramic member side of the cross-sectional curve of the bonding interface between the ceramic member 20 and the metal member 30, which does not intersect with the cross-sectional curve but contacts the cross-sectional curve at two or more points, and a second line segment L2 of 200 μm in length is taken on the metal member side of the cross-sectional curve, which does not intersect with the cross-sectional curve but contacts the cross-sectional curve and forms the opposite side of a rectangle with respect to the reference line segment L1. The distance between the reference line segment L1 and the second line segment L2 is 6.0 μm or more. In other words, the cross-sectional curve of the bonding interface between the ceramic member 20 and the metal member 30 has irregularities of 6.0 μm or more every 200 μm. By increasing the oxygen concentration of the protruding portions 28 of the ceramic member compared to the oxygen concentration of the rest of the ceramic member, the bonding strength between the AlN ceramic and the metal member can be increased, and a bonded body can be obtained in which erosion and contamination of the bonding surface is suppressed.

[0041] 2(a) and 2(b), even in the same cross section, the distance between the reference line segment L1 and the second line segment L2 varies depending on the position of the reference line segment L1. The distance between the reference line segment L1 and the second line segment L2 may be measured using not only a microscope image but also an SEM image or the like, and the magnification is not limited to 500x, but may be any of 200x to 2000x.

[0042] The reason why the oxygen concentration in the protrusions 28 of the ceramic member is higher than that of the other ceramic members is presumably because the natural oxide film formed on the surface of the high-melting-point metal reacts with the high-melting-point metal, producing high-melting-point metal oxides with melting points of 900°C or higher during firing, some of which become molten and diffuse toward the ceramic member. As a result, the ceramic member 20 and the metal member 30 are chemically bonded via oxygen, and the ceramic member, with its increased fluidity, penetrates into the irregularities at the bonding interface, exerting a strong anchor effect, thereby obtaining even higher bonding strength.

[0043] The bonded interface between the ceramic member 20 and the metal member 30 refers to the interface where the concentration of the metal element that primarily constitutes the metal member 30 drops sharply in cross-sectional elemental mapping by EDX or EPMA. The interior of the ceramic member 20 refers to a region at least 1 mm away from the ceramic member 20, perpendicular to the approximated line (hereinafter referred to as the approximated line) when the cross-sectional curve of the bonded interface is approximated by a straight line in a 200x microscope image. When the ceramic member 20 contains a second phase composed of a metal oxide, the interior of the ceramic member 20 may also be referred to as a region where the concentration of the metal that constitutes the second phase of the ceramic member 20 is uniform. If the ceramic member 20 closer to the ceramic member 20 than the reference line L1 is defined as the ceramic member 20 outside the reference line L1, the ceramic member 20 outside the reference line L1 varies depending on the position of the reference line L1. Therefore, the oxygen concentration of the ceramic member 20 outside the reference line L1 may be the oxygen concentration inside the ceramic member 20. The vicinity of the bonding interface is defined as a range within 100 μm perpendicular to the approximate line. The cross-sectional curve of the bonding interface preferably has two or more protrusions of the metal member 30 every 200 μm in the direction of the approximate line.

[0044] The changes in the concentrations of metal, oxygen, and carbon present in the ceramic member 20, the metal member 30, or their bonded interface can be determined by comparing the intensity (count number) of characteristic X-rays in the relevant areas using an EPMA. This allows the relative evaluation of the differences in the concentrations of metal, oxygen, and carbon near and inside the interface.

[0045] The metal member 30 preferably contains 1 wt% or less of the second metal oxide. When the metal member 30 contains 1 wt% or less of the second metal oxide, the bonding strength between the ceramic member 20 and the metal member 30 is increased, and the reliability of the bonded body 10 is improved. The metal constituting the second metal oxide is preferably one or more selected from Y, Ce, and Ca, and more preferably Y or Ce. When the ceramic member 20 contains a second phase made of a metal oxide, the metal constituting the second metal oxide may be the same as the metal constituting the metal oxide of the second phase of the ceramic member 20. These metal oxide components already contained in the metal member 30 can increase the metal and oxygen concentrations at the bonding interface, thereby increasing the bonding strength.

[0046] The metal member 30 preferably has a through-hole penetrating in the thickness direction, or a groove on one main surface 32 or the other main surface 34. By having the metal member 30 have a through-hole penetrating in the thickness direction, or a groove on one main surface 32 or the other main surface 34 in this way, the uses of the joined body 10 are further expanded.

[0047] The metal member 30 may have a carbide layer of a high-melting point metal near the bonding interface between the ceramic member 20 and the metal member 30. Having a carbide layer of a high-melting point metal near the bonding interface means that, when the bonding interface is approximated by a straight line in cross-sectional elemental mapping by EDX or EPMA, C components are detected within an area of ​​100 μm perpendicular to the straight line. Because the carbide layer of a high-melting point metal is an embrittlement layer, the presence of the carbide layer is thought to weaken the bonding strength. However, the bonded body 10 of the present invention can achieve high bonding strength even when a carbide layer is formed.

[0048] 3 is a schematic cross-sectional view showing a modified example of a bonded body according to an embodiment of the present invention. As shown in FIG. 3, it is preferable that a ceramic member 20 is further bonded to the other main surface 34 of the metal member 30, opposite to the one main surface 32. By bonding the ceramic members 20 to both main surfaces 32, 34 of the metal member 30 in this manner, the internal stress of the bonded body 10 is balanced, thereby improving the reliability of the bonded body 10 and further expanding the range of uses of the bonded body 10. Furthermore, by sandwiching the plate-shaped high-melting-point metal (metal member 30) between the ceramic members 20, warping of the bonded body 10 can be suppressed, and a bonded body 10 with high dimensional accuracy can be produced.

[0049] [Configuration of electrode embedding material] Next, an electrode-embedded member according to an embodiment of the present invention will be described. Fig. 4 is a schematic cross-sectional view showing an example of an electrode-embedded member according to an embodiment of the present invention. An electrode-embedded member 50 according to an embodiment of the present invention includes a bonded body 10 and an electrode 40 embedded in a ceramic member 20 of the bonded body 10.

[0050] The joined body 10 is the joined body 10 described above. The electrode 40 is embedded in the ceramic member 20 of the joined body 10. The electrode 40 may have various shapes, such as a mesh shape or a foil shape, and may be made of various materials, such as molybdenum or tungsten. The electrode 40 can be used as a heater electrode.

[0051] The electrode-embedding member 50 may be provided with terminal holes and terminals (not shown).

[0052] The bonded body and electrode-embedded member of the present invention are members that suppress erosion and contamination of the bonding surface between a ceramic member mainly composed of AlN and a metal member made of a high-melting-point metal. Furthermore, since the bonded body and electrode-embedded member of the present invention have a thick metal member, they can be used in a variety of applications, such as using the metal member as a heat sink or heat spreader, or improving the strength and dimensional accuracy of the ceramic member.

[0053] [Method of manufacturing the bonded body] Next, a method for manufacturing the bonded body 10 configured as described above will be described. Figures 5(a) to 5(e) are cross-sectional views each showing a schematic diagram of one stage of the manufacturing process according to the embodiment of the present invention.

[0054] First, granulated powder 22 is prepared by granulating AlN raw material powder or powder obtained by adding metal oxide raw material powder to AlN raw material powder. The AlN raw material powder is preferably highly pure, preferably 96% or more, more preferably 98% or more. The average particle size of the AlN powder is preferably 0.1 μm or more and 1.0 μm or less, more preferably 0.3 μm or more and 0.8 μm or less. When Y2O3, for example, is used as the metal oxide raw material powder, 0.1 wt% to 5 wt% of Y2O3 is added to the AlN raw material powder, and a PVA-based binder, dispersant, and solvent are added to prepare a slurry, which is then granulated using a spray dryer or the like to produce granulated powder 22.

[0055] Next, a metal member precursor 36 is prepared, which will become the metal member 30 after firing. The metal member precursor 36 is made of a plate-shaped high-melting point metal, has a maximum thickness of 1 mm or more in a direction perpendicular to one of its main surfaces, and is roughened so that the irregularities per reference line segment L1 having a length of 200 μm on one of its main surfaces are 6.0 μm or more.

[0056] The metal member precursor 36 is preferably processed so that the center line average roughness Ra is 1.0 μm or more, thereby roughening one of the main surfaces of the metal member precursor 36. The metal member precursor 36 is preferably roughened by blasting. This makes it possible to easily roughen the one main surface so that the irregularities per reference line segment L1 having a length of 200 μm are 6.0 μm or more.

[0057] If Ra is less than 1.0 μm, it becomes relatively difficult for the ceramic region with a high oxygen concentration to penetrate into the unevenness of the bonded interface. Since the bond strength is mainly determined by chemical bonding, there is a risk that the bond strength will be relatively low. Furthermore, it is preferable that the metal member precursor 36 be processed so that the center line average roughness Ra is 5.0 μm or less. Even if Ra is greater than 5.0 μm, bond strength can be obtained, but the processing accuracy of the metal member may deteriorate, which may adversely affect the dimensional accuracy of the bonded body.

[0058] The metal member precursor 36 may be knurled to roughen one of its main surfaces. The knurling may be a conventional pattern such as a crisscross knurl. The knurling may be a cutting process in which the surface of the workpiece is scraped off, or a rolling process in which the workpiece is deformed by applying pressure while being rolled.

[0059] Next, the granulated powder 22 or a compact formed from the granulated powder, and the metal member precursor 36 are stacked in a bottomed carbon mold 60 (molding mold) so that one main surface of the plate-shaped metal member precursor 36 is perpendicular to the stacking direction.

[0060] As another example of laminating compacts, one or more compacts are produced using the obtained granulated powder 22. As a method for forming the compacts, known methods such as uniaxial pressing or cold isostatic pressing (CIP) may be used. Note that the method for forming the compacts is not limited to pressure forming, and for example, green sheet lamination or slip casting may also be applied.

[0061] When producing electrode-embedded member 50, when stacking granulated powder 22, granulated powder 22 is pre-pressed, electrode 40 is arranged, and granulated powder 22 is further added and pre-pressed, or compacts are stacked, electrode 40 is arranged, and further compacts are stacked, whereby electrode 40 is embedded in the portion that will become ceramic member 20 after sintering.

[0062] Next, a carbon punch 70 is inserted into the carbon mold 60 to form the laminate 12. The laminate 12 may be a two-layer structure consisting of a layer of granulated powder 22 or a compact that will become the ceramic member 20 after sintering and a plate-shaped metal member precursor 36 that will become the metal member 30 after sintering, or a three-layer structure in which the plate-shaped metal member precursor 36 is sandwiched between layers of granulated powder 22 or a compact. Furthermore, the side surfaces in the stacking direction may have portions where the plate-shaped metal member precursor 36 is exposed, or the plate-shaped metal member precursor 36 may be covered with the granulated powder 22 or the compact. FIG. 5 shows a case in which the plate-shaped metal member precursor 36 is covered with the granulated powder 22 to form a three-layer structure.

[0063] Next, the laminate 12 is uniaxially pressurized and fired to produce the bonded body 10. The firing conditions are, for example, a temperature of 1700°C to 2000°C, a pressure of 1 MPa or more, and a holding time of 0.1 to 10 hours.

[0064] In this case, the uniaxial pressurized sintering process is controlled so that the granulated powder or compact penetrates into the recesses 38 on one main surface of the metal member precursor 36, and the oxygen concentration of the ceramic member that penetrates into the recesses 38 and is sintered is higher than the oxygen concentration of the ceramic member sintered in the areas other than the recesses 38. That is, in the sintered bonded body 10, the oxygen concentration of the protrusions 28 of the ceramic member is controlled to be higher than the oxygen concentration of the ceramic member other than the protrusions 28. This control is achieved by controlling the sintering conditions, such as the uniaxial pressurizing pressure, sintering temperature, sintering time, and temperature increase / decrease time, depending on the material. For example, in the case of AlN and Mo containing 5 wt% YO, it is preferable to hold the sintering at 900°C to 1500°C for a longer time than usual, for example, 5 hours or more.

[0065] After firing, a process for processing the plate-shaped metal member precursor 36 into a predetermined shape may be performed. At this time, if the side surfaces of the plate-shaped metal member precursor 36 in the stacking direction are covered with ceramic members, processing may be performed to expose the plate-shaped metal member precursor 36. Also, if the plate-shaped metal member precursor 36 is a three-layer structure sandwiched between layers of ceramic members 20, processing may be performed to remove some of the ceramic members 20 or all of one of the ceramic members 20. Also, a process for processing the shape of the plate-shaped metal member precursor 36 may be performed. At this time, processing is performed so that the maximum thickness of the plate-shaped metal member precursor 36 in the direction perpendicular to one main surface 32 is not less than 1 mm.

[0066] In addition, in the case of using the electrode-embedding member 50, a step of exposing a part of the electrode 40 and a step of connecting a terminal to the electrode 40 may be provided.

[0067] The method for producing and laminating a compact may include a step of degreasing the compact to produce a degreased body and a step of calcining the degreased body to produce a calcined body. In this case, for example, the degreasing temperature is preferably 400°C or higher and 800°C or lower, and the degreasing time is preferably 1 hour or higher and 120 hours or lower. The degreasing atmosphere is preferably an air atmosphere or a nitrogen atmosphere, and more preferably an air atmosphere. Furthermore, for example, the calcination temperature is preferably 1200°C or higher and 1700°C or lower, and the calcination time is preferably 0.5 hours or higher and 12 hours or lower. The calcination atmosphere is preferably a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere.

[0068] Furthermore, the plate-shaped metal member precursor 36 preferably has through-holes penetrating in the thickness direction or grooves on one main surface 32 or the other main surface 34. By using a plate-shaped metal member precursor 36 having through-holes penetrating in the thickness direction or grooves on one main surface 32 or the other main surface 34 in this way, the metal member precursor, which is difficult to process, can be processed in advance, and shapes for various structures can be produced more easily than if it were processed after firing, further expanding the uses of the joined body 10.

[0069] 6(a) to 6(e) are cross-sectional views each showing a schematic diagram of one stage of the manufacturing process of a manufacturing method according to an embodiment of the present invention. Fig. 6 shows an example of a manufacturing method using a plate-shaped metal member precursor 36 having through-holes penetrating in the thickness direction and grooves on one main surface 32. Only the differences from the above manufacturing method will be explained.

[0070] In the process of preparing a plate-shaped metal member precursor 36 having a thickness of 1 mm or more, through-holes penetrating the plate-shaped metal member precursor 36 in the thickness direction or grooves on one main surface 32 or the other main surface 34 are machined in accordance with the design of the joined body 10. One main surface of the metal member precursor 36 is then roughened so that the unevenness per reference line segment having a length of 200 μm on one main surface is 6.0 μm or more. Furthermore, in the process of forming the laminate 12, it is preferable to fill the through-holes or grooves of the plate-shaped metal member precursor 36 formed by machining with the granulated powder 22 or a compact formed from the granulated powder. Filling the through-holes or grooves with the granulated powder or the like and firing the ceramic member in this manner reduces the risk of defects occurring in the fired ceramic member. In addition to the granulated powder 22 or a compact formed from the granulated powder, a calcined or fired product of these may also be filled.

[0071] After firing, the product is processed into a predetermined shape. By processing the ceramic-filled regions of the through-holes or grooves of the plate-shaped metal member precursor 36, the burden of post-processing after firing can be reduced. The through-holes are used, for example, as holes for later attachment of power supply terminals for electrode extraction, holes for supplying or suctioning gas, and holes for lift pins for mounting the substrate. In this case, electrical insulation functionality can be added by processing the through-holes while leaving some of the ceramic material filled therein. The grooves are used, for example, as part of a refrigerant flow path.

[0072] By using this method, it is possible to manufacture a bonded body or an electrode-embedded member in which corrosion and contamination of the bonding surfaces of a ceramic member mainly composed of AlN and a metal member made of a high-melting-point metal are suppressed.

[0073] [Example] (Preparation of junction) Example 1 5 wt% Y2O3 was added to the AlN raw powder, and a binder (PVA), dispersant, and solvent were added to prepare a slurry, which was then granulated using a spray dryer. Additionally, a plate-shaped Mo with a diameter of 50 mm, a thickness of 5 mm, and a surface roughened by blasting to a centerline average roughness Ra of 2.0 μm on the main surface was prepared as a precursor to the plate-shaped metal component that would become the metal component. The blasting was performed using SiC powder with a particle size of #100 and an air pressure of 0.15 MPa.

[0074] Next, the granulated powder was filled into a bottomed carbon mold and press-molded with a carbon punch to produce a compact with a diameter of 80 mm and a thickness of 10 mm. Mo was then placed on the compact. Next, the carbon mold was further filled with the granulated powder to embed the Mo. At this time, the granulated powder was filled and molded with the carbon punch so that the thickness from the top surface of the Mo was 10 mm.

[0075] Then, with the carbon punch inserted into the carbon mold, uniaxial hot press sintering was performed for 2 hours at a temperature of 1800°C, a pressure of 4 MPa, and a N2 atmosphere. This resulted in a 50 mm diameter metal member made of Mo, a high-melting-point metal, embedded inside an 80 mm diameter AlN sintered body. In this way, the bonded body of Example 1 was produced. After that, multiple test pieces of Example 1 measuring 3 mm x 4 mm x 19 mm were cut out so that the long sides were aligned in the stacking direction.

[0076] Example 2 A joined body of Example 2 was produced using the same process and conditions as in Example 1, except that the granulated powder was changed to AlN raw material powder to which 5 wt % of Y2O3 and 0.9 wt % of TiN were added.

[0077] Example 3 A joint body of Example 3 was produced using the same process and conditions as in Example 1, except that the high melting point metal was replaced with an alloy in which 0.4 wt % of Y2O3 was added to Mo.

[0078] Example 4 A joined body of Example 4 was produced using the same process and conditions as in Example 1, except that the high-melting-point metal was replaced with W.

[0079] Example 5 A joined body of Example 5 was produced using the same steps and conditions as in Example 1, except that the granulated powder was changed to only AlN raw material powder.

[0080] Example 6 A bonded body of Example 6 was produced using the same steps and conditions as Example 1, except that the firing time was changed to 5 hours.

[0081] Example 7 A joined body of Example 7 was produced using the same process and conditions as Example 1, except that the granulated powder of Example 1 was changed to AlN raw material powder to which 7 wt % of YO was added, and the resulting mixture was uniaxially hot-pressed at a temperature of 1800°C under a pressure of 4 MPa in a N atmosphere for 10 hours.

[0082] Example 8 A joined body of Example 8 was produced using the same steps and conditions as in Example 1, except that the main surfaces of the metal member precursor of Example 1 were knurled. The knurling was performed according to JIS B 0951 with a cross pattern of m0.5.

[0083] Example 9 A bonded body of Example 9 was produced using the same steps and conditions as in Example 1, except that the main surfaces of the metal member precursor of Example 1 were roughened to Ra 4.0 μm.

[0084] Example 10 A bonded body of Example 10 was produced using the same steps and conditions as in Example 1, except that the main surfaces of the metal member precursor of Example 1 were roughened to Ra 1.2 μm.

[0085] (Comparative Example 1) A bonded body of Comparative Example 1 was produced using the same steps and conditions as in Example 1, except that the main surface of the metal member precursor of Example 1 was not roughened. The Ra was 0.8 μm.

[0086] (Comparative Example 2) A bonded body of Comparative Example 2 was produced using the same steps and conditions as in Example 2, except that the main surface of the metal member precursor of Example 2 was not roughened. The Ra was 0.8 μm.

[0087] (Bonding strength measurement) The bond strength of the bonded bodies was measured using a three-point bending strength test in accordance with JIS R1601 2008 (room temperature bending strength test method for fine ceramics). The span was 10 mm, and the bond surface was placed at the center in the longitudinal direction, with the knife edge aligned with the bond surface. Five test pieces were prepared for each sample, and the average of the five measurements was used as the bond strength value for each sample.

[0088] [Table 1]

[0089] (Measurement results) As shown in Table 1, the bond strength of Comparative Example 1 was 77 MPa, and the bond strength of Comparative Example 2 was 115 MPa. In contrast, Example 1 had a bond strength of 325 MPa, which was about four times higher than the conventional Comparative Example. Examples 2, 4, 6, 7, 8, and 10 had bond strengths of 290 MPa, 240 MPa, 270 MPa, 215 MPa, 300 MPa, and 180 MPa, respectively, which were lower than the sample of Example 1 but higher than the Comparative Examples. Furthermore, Examples 3, 5, and 9 had bond strengths of 330 MPa, 345 MPa, and 340 MPa, respectively, which were higher than the sample of Example 1.

[0090] (Measurement of the distance between the reference line segment and the second line segment) Next, for the samples of Examples 1 to 10 and Comparative Examples 1 and 2, the distance between the reference line segment and the second line segment was measured in a 500x microscope image of a cross section perpendicular to one main surface of the metal member.

[0091] (Measurement results) As shown in Table 1, the minimum distance between the reference line segment and the second line segment in Comparative Examples 1 and 2 was 4 μm. In contrast, in Example 1, the minimum distance between the reference line segment and the second line segment was 14 μm, which was found to be significantly longer than the conventional comparative examples. In Examples 2, 5 to 7, the minimum distance between the reference line segment and the second line segment was 15 μm, which was found to be longer than the sample in Example 1. In Example 4, the minimum distance between the reference line segment and the second line segment was 16 μm, which was found to be longer than the sample in Example 1. In Example 8, the minimum distance between the reference line segment and the second line segment was 120 μm, which was found to be significantly longer than the sample in Example 1. In Example 9, the minimum distance between the reference line segment and the second line segment was 29 μm, which was found to be longer than the sample in Example 1. In Example 10, the minimum distance between the reference line segment and the second line segment was 7 μm, which was shorter than that of the sample in Example 1, but longer than that of the comparative example.

[0092] (Elemental analysis) Next, the cut surface of the sample of the example perpendicular to the stacking direction was subjected to elemental analysis and mapping using an EPMA. Figures 7(a) to 7(g) are photographs showing the EPMA mapping of Example 2. Figure 7(a) is an SEM image of the analyzed field of the cross section of Example 2 taken at 2000x magnification. Figures 7(b) to 7(g) are photographs in which Al, Mo, O, N, Ti, and Y are mapped, respectively.

[0093] 7(a) to (d), it was found that O was present in the ceramic member (AlN), but in greater amounts at the protruding parts of the ceramic member. In other words, it was confirmed that the oxygen concentration in the ceramic member at the bonding interface between the ceramic member and the metal member was higher than the oxygen concentration inside the ceramic member.

[0094] The convex parts of the ceramic member contain relatively large amounts of Al and O, but little N. Therefore, it is estimated that the bonding interface between the metal member and the ceramic member is formed by a chemical bond such as -Mo-(O-Al)-N-.

[0095] Furthermore, it is presumed that the components formed on the convex portions of the ceramic member have a relatively low melting point and easily penetrate into the concave portions of the metal member, thereby exerting a physical anchoring effect.

[0096] 8(a) and 8(b) are SEM images of the cross sections of Example 1 and Comparative Example 1, respectively, taken at 2000x magnification. The cross sections of the same field of view were previously subjected to elemental analysis using an EPMA, and the results were compared with the results of the SEM images, which revealed that the vicinity of the bonding interface of the bonded body was layered in the order of AlN ceramic layer, oxygen-rich AlN ceramic layer, and high-melting-point metal Mo layer, from top to bottom, in the SEM image of FIG. 7. Furthermore, the cross section of Comparative Example 1 was also found to have a similar structure, although the thickness of each layer was different.

[0097] The AlN ceramic layer and the oxygen-rich AlN ceramic layer in Example 1 exhibited different color tones in the SEM images, with the oxygen-rich AlN ceramic layer being darker than the other AlN ceramic layers. Furthermore, the oxygen-rich AlN ceramic layer was present in large quantities at the bonding interface and on the convex portions of the ceramic members. In contrast, in Comparative Example 1, the oxygen-rich AlN ceramic layer is also thought to be present near the bonding interface, but is not clearly visible. Therefore, it was confirmed that by roughening one of the main surfaces so that the irregularities per 200 μm reference line segment were 6.0 μm or more, an oxygen-rich AlN ceramic layer was formed at the bonding interface and on the convex portions of the ceramic members.

[0098] Example 11 The metal member precursor of Example 1 was a plate-shaped Mo plate with a diameter of 60 mm and a thickness of 10 mm, with four 6 mm through-holes (PCD 0.40 mm, evenly spaced). Furthermore, grooves with a width of 5 mm and a depth of 5 mm were formed perpendicularly through the center of the metal member, and the upper and lower surfaces of the 60 mm diameter were roughened to an Ra of 4.0 μm. The metal member was then placed on a molded body with a diameter of 80 mm. Granulated powder was then filled into the through-holes and grooves of the metal member, and the granulated powder was further added to embed the Mo to a depth of 10 mm from the top surface of the Mo. A joined body of Example 11 was fabricated using the same process and conditions. The distance between the reference line segment and the second line segment in Example 11 was 26 μm.

[0099] After firing the bonded body of Example 11, holes penetrating the through-holes of the Mo plate and grooves reaching the grooves of the Mo plate were formed in the ceramic member. Both were easier to form than machining the Mo plate after firing the bonded body. It was confirmed that when it is necessary to form such a structure in the bonded body, it is preferable to process the plate-shaped metal member precursor in advance before firing.

[0100] Example 12 (Production of electrode-embedded member) In Example 12, a heater electrode was embedded in an AlN sintered body (ceramic member) located on a metal member precursor in the manufacturing method of Example 1, to produce a heater module that can be used in high-temperature processes.

[0101] The same granulated powder as in Example 1 was prepared. Furthermore, a plate-shaped Mo having a diameter of φ300 mm and a thickness of 8 mm was prepared as a plate-shaped metal member precursor to become the metal member. The upper and lower surfaces of the metal member having a diameter of φ300 mm were then roughened to Ra 2.0 μm.

[0102] First, a heater laminate was produced. The granulated powder was filled into a bottomed carbon mold and press-molded with a carbon punch to produce a compact with a diameter of 320 mm and a thickness of 8 mm. Next, a heater electrode was placed on the mold. The heater electrode was a Mo mesh (wire diameter 0.1 mm, mesh size #50, plain weave) cut into a predetermined pattern to match the resistance value of the heater electrode. Next, the granulated powder was further filled into the carbon mold to embed the heater electrode, producing a heater laminate. At this time, the granulated powder was filled and molded with a carbon punch so that the thickness from the top surface of the heater electrode was 8 mm.

[0103] Next, plate-shaped Mo was placed on the heater laminate. The carbon mold on which the Mo was placed was further filled with granulated powder to embed the Mo. At this time, the plate-shaped Mo was formed with a carbon punch so that the thickness from the top surface was 8 mm, and a laminate was produced. In this way, a heater laminate and a laminate in which plate-shaped Mo were stacked were produced.

[0104] Then, with the carbon punch inserted into the carbon mold, uniaxial hot press firing was performed at a temperature of 1800°C, a pressure of 4 MPa, and a N2 atmosphere for 4 hours. After firing, the outer shape (φ300 mm x 18 mm) was processed. Drilling terminal holes for connecting the electrodes to an external power supply, connecting the terminals, and fabricating the necessary insulating structure were all performed simultaneously during processing after firing. In this way, the electrode-embedded member of Example 12 was produced.

[0105] (evaluation) The fabricated heater module could be heated to 400°C by applying electricity to the heater electrodes from an external power source.

[0106] From the above, it was confirmed that the bonded body and electrode-embedded member of the present invention can suppress erosion and contamination of the bonding surface, have high bonding strength, and have thick metal members. It was also confirmed that the manufacturing method of the present invention can manufacture such a bonded body or electrode-embedded member.

[0107] The present invention is not limited to the above-described embodiments, and various modifications and equivalents are included within the spirit and scope of the present invention. Furthermore, the structure, shape, number, position, size, etc. of the components shown in each drawing are for the convenience of explanation and may be changed as appropriate. [Explanation of symbols]

[0108] 10 zygote 12 Laminate 20 Ceramic materials 22 Granulated powder 28 Convex part 30 Metallic parts 32 One main surface 34 Other main surface 36 Metallic component precursors 38 Recess 40 electrodes 50 Electrode embedding member 60 Carbon type 70 Carbon Punch

Claims

1. A joined body of a ceramic member mainly composed of AlN and a metal member made of a high-melting-point metal having a melting point of 2000°C or higher, the ceramic member is bonded to at least one main surface of the metal member, The metal member has a maximum thickness of 1 mm or more in a direction perpendicular to one main surface of the metal member, In a 500x microscope image of a cross section perpendicular to one main surface of the metal member, a reference line segment having a length of 200 μm that does not intersect with the cross-sectional curve at the joining interface between the ceramic member and the metal member and that contacts the cross-sectional curve at two or more points on the ceramic member side is taken, and a second line segment having a length of 200 μm that does not intersect with the cross-sectional curve and that contacts the metal member side of the cross-sectional curve and forms an opposite side of a rectangle with respect to the reference line segment is taken, and the distance between the reference line segment and the second line segment is 6.0 μm or more; A bonded body, characterized in that the oxygen concentration of the ceramic members inside the reference line segment and the second line segment is higher than the oxygen concentration of the ceramic members outside the reference line segment.

2. 2. The joined body according to claim 1, wherein the ceramic member includes a second phase made of a metal oxide.

3. 3. The joined body according to claim 1, wherein the metal member contains 1 wt % or less of the second metal oxide.

4. 4. The joined body according to claim 1, wherein the ceramic member contains a metal of Group 4 of the periodic table.

5. 5. The joined body according to claim 1, wherein the metal member has a through hole penetrating in the thickness direction, or a groove on the one main surface or the other main surface opposite to the one main surface.

6. 6. The joined body according to claim 1, wherein a ceramic member is further joined to the other main surface of the metal member opposite to the one main surface of the metal member.

7. The bonded body according to any one of claims 1 to 5, an electrode embedded in the ceramic member of the joined body;

8. A method for manufacturing a joined body of ceramic members mainly composed of AlN and metal members made of a high-melting-point metal having a melting point of 2000°C or higher, comprising: preparing a granulated powder by granulating AlN raw material powder or a powder obtained by adding a metal oxide raw material powder to the AlN raw material powder; preparing a metal member precursor that will become the metal member after firing, the metal member precursor being made of the high-melting point metal in a plate shape, having a maximum thickness of 1 mm or more in a direction perpendicular to one main surface, and being surface-roughened so that irregularities per reference line segment having a length of 200 μm on the one main surface are 6.0 μm or more; stacking the granulated powder or a compact formed from the granulated powder, and the metal member precursor on a carbon mold such that the one main surface of the metal member precursor is perpendicular to a stacking direction; inserting a carbon punch into the carbon mold to form a laminate; and uniaxially pressing and firing the laminate, the uniaxial pressure sintering step is performed at 1800°C for 2 hours or more, or at 900°C to 1500°C for 5 hours or more, so that the granulated powder or the compact penetrates into recesses on the one main surface of the metal member precursor, and the oxygen concentration of the ceramic member that has penetrated into the recesses and been fired is controlled to be higher than the oxygen concentration of the ceramic member that has been fired outside the recesses.

9. The manufacturing method according to claim 8 , wherein the metal member precursor has a through-hole penetrating in a thickness direction, or a groove on the one main surface or the other main surface opposite to the one main surface.

Images