Manufacturing method for bonded substrate, bonded substrate, and light-emitting module

Abstract

To provide a manufacturing method for a bonded substrate in which a bonded substrate with superior heat conductivity can be manufactured while internal cracking is reducible.SOLUTION: A manufacturing method for bonded substrate includes: subjecting a first surface of a metal plate to blast processing using an abrasive material of μm or more 15 and 50 μm or less in median diameter; imparting a bonding material containing silver onto the first surface of the metal plate; arranging first ceramics on the first surface of the metal plate with the adhesive material interposed; and heating the bonding material to equal to or higher than a softening temperature of the bonding material to bond the metal plate and the first ceramics.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a bonded substrate, a bonded substrate, and a light-emitting module.

Background Art

[0002] In a light-emitting module having a light-emitting element such as a light-emitting diode, the light emission amount of the mounted light-emitting element has been increasing year by year, and since the light-emitting elements are highly integrated, the amount of heat generation has increased, and heat countermeasures have become an issue.

[0003] As a substrate for a light-emitting module, a bonded substrate in which a copper plate and a ceramic plate such as Si3N4 are bonded via a bonding brazing material is known (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a method for manufacturing a bonded substrate that can reduce the occurrence of internal cracks and can manufacture a bonded substrate having excellent thermal conductivity.

Means for Solving the Problems

[0006] The method for manufacturing a bonded substrate according to an embodiment of the present disclosure includes performing a blasting process on a first surface of a metal plate using an abrasive having a median diameter of 15 μm or more and 50 μm or less, applying a bonding material containing silver on the first surface of the metal plate, disposing a first ceramic on the first surface of the metal plate via the bonding material, and heating the bonding material to a temperature equal to or higher than the softening temperature of the bonding material to bond the metal plate and the first ceramic. A bonded substrate according to another embodiment of the present disclosure includes a metal plate having a first surface and a second surface opposite to the first surface, a first ceramic, and a metal body containing silver disposed between the first surface of the metal plate and the first ceramic. In a cross-sectional view, it has a central layer of central crystal grains near the center of the metal plate and a first layer of first crystal grains having a smaller median diameter than the central crystal grains on the first surface side. A light-emitting module according to another embodiment of the present disclosure includes the bonded substrate and a plurality of light-emitting elements disposed on the bonded substrate.

Advantages of the Invention

[0007] According to an embodiment of the present disclosure, it is possible to provide a method for manufacturing a bonded substrate that can reduce the occurrence of internal cracks and manufacture a bonded substrate with excellent thermal conductivity.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Mode for Carrying Out the Invention

[0009] Hereinafter, a manufacturing method of an embodiment according to the present invention, a bonded substrate obtained by the manufacturing method (hereinafter sometimes referred to as "bonded substrate according to the embodiment"), and a light-emitting module (hereinafter sometimes referred to as "light-emitting module according to the embodiment") will be described with reference to the drawings. In the following description, terms indicating a specific direction or position (for example, "up", "down", and other terms including those terms) are used as necessary. However, the use of those terms is for facilitating the understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meanings of those terms. Also, parts denoted by the same reference numerals appearing in a plurality of drawings indicate the same or equivalent parts or members.

[0010] In addition, the embodiments described below exemplify a bonded substrate, a light-emitting module, etc. for embodying the technical idea of the present invention, and do not limit the present invention as follows. Also, the dimensions, materials, shapes, relative arrangements, etc. of the components described below are not intended to limit the scope of the present invention only to those, but are intended to be illustrative unless otherwise specifically described. Also, the content described in one embodiment is applicable to other embodiments and modifications. Also, the sizes and positional relationships of the members shown in the drawings may be exaggerated for clarity of explanation. Furthermore, in order to avoid the drawings becoming overly complex, schematic diagrams omitting the illustration of some elements or end views showing only the cut surface as a cross-sectional view may be used.

[0011] <Bonded Substrate According to Embodiment> A bonded substrate 1, which is an example of a bonded substrate according to an embodiment, will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view schematically showing the bonded substrate 1.

[0012] The bonded substrate 1 includes a metal plate 3 having a first surface 3A and a second surface 3B opposite to the first surface 3A, a first ceramic 4, and a first metal body 5 containing silver disposed between the first surface 3A of the metal plate 3 and the first ceramic 4. In a cross-sectional view, the bonded substrate 1 has a central layer 3c of central crystal grains near the center of the metal plate 3 and a first layer 3a of first crystal grains having a median diameter smaller than that of the central crystal grains on the first surface 3A side.

[0013] FIG. 2 is a cross-sectional view schematically showing a bonded substrate 2, which is another example of a bonded substrate according to an embodiment.

[0014] The bonded substrate 2 is a mode having a second ceramic 6 and a second metal body 7 in addition to the bonded substrate 1. The bonded substrate 2 includes a metal plate 3 having a first surface 3A and a second surface 3B opposite to the first surface 3A, a first ceramic 4, a first metal body 5 containing silver and disposed between the first surface 3A of the metal plate 3 and the first ceramic 4, a second ceramic 6, and a second metal body 7 containing silver and disposed between the second surface 3B of the metal plate 3 and the second ceramic 6. In a cross-sectional view, the bonded substrate 2 has a central layer 3c of central crystal grains near the center of the metal plate 3, a first layer 3a of first crystal grains having a median diameter smaller than that of the central crystal grains on the first surface 3A side, and a second layer 3b of second crystal grains having a median diameter smaller than that of the central crystal grains on the second surface 3B side.

[0015] In a conventional bonded substrate in which a copper plate and a ceramic plate such as Si3N4 are bonded via a bonding brazing material containing silver, silver contained in the bonding brazing material may diffuse into the copper plate, resulting in internal cracks in the bonded substrate. In contrast, the method for manufacturing a bonded substrate according to the present embodiment can refine the crystal structure on the surface of the metal plate by performing a blasting process on the surface of the metal plate. Thereby, the diffusion of the metal derived from the metal body can be reduced, the occurrence of internal cracks in the bonded substrate can be reduced, and a bonded substrate having excellent thermal conductivity can be manufactured.

[0016] Hereinafter, each configuration of the bonded substrate 1 and the bonded substrate 2 will be described.

[0017] (Metal plate) The metal plate 3 is a metal plate having excellent heat dissipation. The metal plate 3 has a first surface 3A and a second surface 3B opposite to the first surface 3A. The planar shape of the metal plate 3 is, for example, rectangular and is not particularly limited.

[0018] The metal plate 3 is preferably a metal such as copper, nickel, aluminum, molybdenum, a laminated plate composed of two or more of these metals, or an alloy of two or more of these metals, and more preferably copper. This is because it has a high thermal conductivity. The thickness of the metal plate 3 can be, for example, 100 μm or more and 1000 μm or less, and preferably 200 μm or more and 600 μm or less. This is because it can be thinned while maintaining a certain strength.

[0019] In a cross-sectional view of the bonded substrate 1, the metal plate 3 has a central layer 3c of central crystal grains near the center, and a first layer 3a of first crystal grains having a circular equivalent diameter smaller than that of the central crystal grains on the first surface 3A side. In a cross-sectional view of the bonded substrate 2, the metal plate 3 has a central layer 3c of central crystal grains near the center, a first layer 3a of first crystal grains having a circular equivalent diameter smaller than that of the central crystal grains on the first surface 3A side, and a second layer 3b of second crystal grains having a circular equivalent diameter smaller than that of the central crystal grains on the second surface 3B side.

[0020] The average circular equivalent diameter of the central crystal grains is preferably 200 μm or more and 800 μm or less, and more preferably 200 μm or more and 600 μm or less. On the first surface 3A of the metal plate 3, the number of crystal grains having a circular equivalent diameter larger than 350 μm is preferably 10 grains / mm 2 or less, more preferably 5 grains / mm 2 or less, and even more preferably not contained. On the second surface 3B of the metal plate 3, the number of crystal grains having a circular equivalent diameter larger than 350 μm is preferably 10 grains / mm 2 or less, more preferably 5 grains / mm 2 or less, and even more preferably not contained. Regarding the method for evaluating the circular equivalent diameter of the central crystal grains and the crystal grains on the first surface 3A and the second surface 3B of the metal plate 3, it can be measured by the method described in the <Method for manufacturing a bonded substrate according to an embodiment> and [Examples] described later.

[0021] The average thickness of the first layer 3a and the average thickness of the second layer 3b are each preferably 0.05 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 3 μm or less. In a cross-sectional view, the average thickness of the first layer 3a and the average thickness of the second layer 3b are each preferably 1 / 50 or more and 1 / 10 or less with respect to the total thickness of the metal plate 3. The average thickness and the total thickness of the metal plate 3 can be obtained by observing the cross-section of the metal plate 3 with an electron microscope, measuring the thickness at three or more arbitrary locations, and taking the average value.

[0022] The surface roughness Ra of the first layer 3a and the surface roughness Ra of the second layer 3b are each preferably 0.01 μm or more and 6 μm or less, more preferably 0.3 μm or more, still more preferably 3 μm or less, and particularly preferably 1 μm or less. The surface roughness can be measured in accordance with the standard of JIS B0601:1994. The surface roughness can be measured, for example, using a stylus profiler manufactured by KLA-Tencor Corporation.

[0023] (First ceramic) The first ceramic 4 is an insulating and plate-shaped member. The first ceramic 4 has a first surface 4A and a second surface 4B on the side opposite to the first surface 4A. The planar shape of the first ceramic 4 is, for example, rectangular. The thickness of the first ceramic 4 can be, for example, 100 μm or more and 500 μm, and preferably 50 μm or more and 200 μm.

[0024] The first ceramic 4 is fired and formed, and is not in a softened state before firing. The first ceramic 4 may be formed by firing ceramics, or commercially available products or the like may be used. The first ceramic 4 can be a ceramic containing at least one selected from silicon nitride, aluminum nitride, boron nitride, magnesium oxide, aluminum oxide, and silicon carbide, and preferably contains silicon nitride or aluminum nitride. Note that the first ceramic 4 is preferably a nitride-based ceramic such as silicon nitride, aluminum nitride, or boron nitride, but oxide-based ceramics such as aluminum oxide, silicon oxide, calcium oxide, and magnesium oxide may also be used. Further, the first ceramic 4 may also use beryllium oxide, silicon carbide, mullite, borosilicate glass, etc.

[0025] (First metal body) The first metal body 5 is a metal body formed by firing the first bonding material 5a. The first metal body 5 is disposed between the first surface 3A of the metal plate 3 and the first surface 4A of the first ceramic 4. The first metal body 5 is preferably disposed on the entire surface (100%) of the first surface 3A of the metal plate 3.

[0026] The first metal body 5 has a metal as the main component, preferably contains silver (Ag) and copper (Cu), and preferably further contains at least one of Cr, Ni, Al, Zn, and Sn. The total content of silver and copper is preferably 85% by mass or more of the entire first metal body 5. Further, the first metal body 5 preferably contains an activation metal such as Ti, Ce, Zr, and Mg.

[0027] (The second ceramic) The second ceramic 6 is an insulating and plate-shaped member. The second ceramic 6 has a first surface 6A and a second surface 6B on the opposite side of the first surface 6A. The planar shape of the second ceramic 6 is, for example, rectangular, and is not particularly limited. The material, shape, etc. of the second ceramic 6 can be appropriately selected from the matters described for the first ceramic 4.

[0028] (The second metal body) The second metal body 7 is a metal body formed by firing the second bonding material 7a. The second metal body 7 is disposed between the second surface 3B of the metal plate 3 and the first surface 6A of the second ceramic 6. The second metal body 7 is preferably disposed on the entire surface (100%) of the second surface 3B of the metal plate 3. The components, etc. of the second metal body 7 can be appropriately selected from the matters described for the first metal body 5.

[0029] In the bonded substrate 1, the thermal conductivity of the first metal body 5 is preferably higher than the thermal conductivity of the first ceramic 4. Further, in the bonded substrate 2, the thermal conductivity of the first metal body 5 is preferably higher than the thermal conductivity of the first ceramic 4 and the thermal conductivity of the second ceramic 6.

[0030] The bonded substrate 1 having the above configuration has, in a cross-sectional view, a first layer 3a of first crystal grains having a median diameter smaller than that of the central crystal grains constituting the central layer 3c on the first surface 3A side. Due to the refinement of the crystal structure of the first surface 3A of the metal plate 3, the diffusion of the metal derived from the first metal body 5 can be reduced, the generation of internal cracks in the bonded substrate 1 can be reduced, and a bonded substrate with excellent thermal conductivity can be manufactured. The bonded substrate 2 having the above configuration further has a second layer 3b of second crystal grains having a median diameter smaller than that of the central crystal grains constituting the central layer 3c on the second surface 3B side in a cross-sectional view. Due to the refinement of the crystal structure of the second surface 3B of the metal plate 3, the diffusion of the metal derived from the second metal body 7 can be reduced, the generation of internal cracks in the bonded substrate 2 can be reduced, and a bonded substrate excellent in thermal conductivity can be manufactured.

[0031] Furthermore, the bonded substrate 1 and the bonded substrate 2 can suppress the warpage of the metal plate 3, and the bonded substrate 2 can further suppress the warpage of the metal plate 3.

[0032] <Light-emitting module according to the embodiment> The light-emitting module 100 according to the embodiment includes the bonded substrate 1 or 2 according to the embodiment and a light-emitting element 30 disposed on the bonded substrate 1 or 2. The light-emitting module 100 preferably further includes a covering member 70 disposed around the light-emitting element 30.

[0033] FIG. 3 is a perspective view schematically showing the light-emitting module according to the present embodiment. FIG. 4 is a perspective view schematically showing the light-emitting module according to the present embodiment with a part of its configuration omitted. FIG. 5 is a plan view schematically showing the light-emitting module according to the present embodiment. FIG. 6 is an end view taken along line VI-VI of FIG. 3. FIG. 7 is an end view taken along line VII-VII of FIG. 3.

[0034] The light-emitting module 100 according to the present embodiment includes a first substrate 10 which is the bonded substrate according to the present embodiment, a second substrate 20, a light-emitting element 30, a wire 40, a first frame portion 50, a second frame portion 60, and a covering member 70.

[0035] The light-emitting module 100 may include a light-transmitting member 80 that covers the upper surfaces of the plurality of light-emitting elements 30. Further, the light-emitting module 100 may include a reflective member 90 that exposes the upper surfaces of the plurality of light-emitting elements 30 and covers the side surfaces in the element mounting region 10r of the upper surface 10a of the first substrate 10. Hereinafter, the case where the light-emitting module 100 includes the light-transmitting member 80 and the reflective member 90 will be described.

[0036] In FIG. 4, for convenience of illustration, a part of each of the covering member 70, the first frame portion 50, the second frame portion 60, and the light-transmissive member 80 is omitted, and a part of each of the wire 40 and the light-emitting element 30 is visualized. Further, in FIG. 5, for convenience of illustration, the covering member 70 is omitted, and the wire 40, the first frame portion 50, the second frame portion 60, etc. are visualized.

[0037] The first substrate 10 has, on its upper surface 10a, an element mounting region 10r and a first terminal 11 disposed outside the element mounting region 10r. The light-emitting element 30 is disposed in the element mounting region 10r of the first substrate 10. The second substrate 20 has, on its upper surface 20a, a substrate mounting region 20r for mounting the first substrate 10 and a second terminal 22 disposed outside the substrate mounting region 20r.

[0038] The first substrate 10 is mounted on the substrate mounting region 20r of the second substrate 20. A first frame portion 50 surrounding the element mounting region 10r is disposed inside the first terminal 11 on the upper surface 10a of the first substrate 10. A second frame portion 60 surrounding the first substrate 10 is disposed outside the second terminal 22 on the upper surface 20a of the second substrate 20.

[0039] The first terminal 11 of the first substrate 10 is electrically connected to the second terminal 22 of the second substrate 20 by a wire 40. The first terminal 11, the second terminal 22, and the wire 40 are located between the first frame portion 50 and the second frame portion 60 in a plan view. The first terminal 11, the second terminal 22, and the wire 40 are covered by a covering member 70.

[0040] (Light-emitting element) The light-emitting element 30 is, for example, substantially rectangular in plan view. The light-emitting element 30 can be, for example, square with one side being 40 μm or more and 100 μm or less in plan view. The light-emitting element 30 includes a semiconductor laminate and positive and negative electrodes disposed on the surface of the semiconductor laminate. The light-emitting element 30 has positive and negative electrodes on the same surface side, and is flip-chip mounted on the first substrate 10 with the surface having the electrodes as the lower surface. In this case, the upper surface located on the side opposite to the surface where the electrodes are disposed becomes the main light extraction surface of the light-emitting element 30. In the light-emitting module 100, the light-emitting elements 30 are arranged and mounted on the first substrate 10 at predetermined intervals in each of the row and column directions. The size and number of the light-emitting elements 30 to be used can be appropriately selected according to the form of the light-emitting module to be obtained. Among them, it is preferable to mount more small light-emitting elements 30 at a higher density. Thereby, the irradiation range of the light emitted from the light-emitting module 100 can be controlled with a larger number of divisions. Such a light-emitting module 100 can be used as a light source of a high-resolution lighting system. For example, the number of the light-emitting elements 30 included in the light-emitting module 100 can be 1000 or more and 20000 or less.

[0041] The light-emitting element 30 can select substances of any wavelength. For example, as the light-emitting element 30 that emits blue light or green light, those using a nitride semiconductor (In X Al Y Ga 1-X-Y N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) can be selected. Also, as the light-emitting element 30 that emits red light, semiconductors represented by GaAlAs or AlInGaP can be used. Furthermore, semiconductor light-emitting elements made of materials other than these can also be used. The composition and emission color of the light-emitting element 30 to be used can be appropriately selected according to the purpose.

[0042] The light-emitting element 30 is joined by a conductive joining member onto a wiring disposed in the element mounting region 10r of the first substrate 10. When flip-chip mounting the light-emitting element 30 onto the first substrate 10, as the joining member, bumps made of a metal material such as Au, Ag, Cu, Al, etc. can be used. Also, as the joining member, solder such as AuSn-based alloy or Sn-based lead-free solder may be used. Further, as the joining member, a conductive adhesive in which a resin contains conductive particles such as metal can also be used. For joining the light-emitting element 30 and the first substrate 10, a plating method may be used. As the plating material, for example, Cu can be mentioned. Also, the electrode of the light-emitting element 30 and the wiring of the first substrate 10 may be in direct contact without passing through a joining member, that is, the electrode of the light-emitting element 30 and the wiring of the first substrate 10 may be in direct contact with each other.

[0043] (Covering member) The covering member 70 is a light-shielding member that covers the wire 40 outside the element mounting region 10r. As an example, the covering member 70 is arranged in a frame shape in a plan view so as to cover the wire 40 and surround the element mounting region 10r. The covering member 70 is arranged so as to be in contact with the first frame portion 50 and the second frame portion 60.

[0044] The covering member 70 is arranged at a distance from the light-emitting element 30 in a plan view. Examples of the distance between the light-emitting element 30 and the covering member 70 include 100 μm or more and 500 μm or less. Also, in a plan view, the width of the covering member 70 located on the long side of the first substrate 10 is wider than the width of the covering member 70 located on the short side of the first substrate 10. The height of the covering member 70 is preferably arranged so as to be highest directly above the top 40t of the wire 40. In other words, it is preferable that the covering member 70 is arranged such that the top 70t of the covering member 70 overlaps with the top 40t of the wire 40. Further, the position of the top 70t of the covering member 70 is preferably arranged to be above the top of the first frame portion 50. In this specification, the width of the covering member 70 located on the long side and the short side of the first substrate 10 refers to the width in a direction perpendicular to the long side and the short side of the first substrate 10 in a plan view. Also, the height of the covering member 70 refers to the distance from the upper surface of the second substrate 20 to the upper surface of the covering member 70.

[0045] Examples of the covering member 70 include a resin containing a light-shielding filler. As the base resin used for the covering member 70, for example, a silicone resin, a modified silicone resin, an epoxy resin, a modified epoxy resin, an acrylic resin, etc. can be used. As the light-shielding filler, light-absorbing substances such as pigments, carbon black, titanium black, graphite, etc., and light-reflecting substances such as titanium oxide, aluminum oxide, zinc oxide, barium carbonate, barium sulfate, boron nitride, aluminum nitride, glass filler, etc. can be preferably used. Specifically, examples of the appearance color of the covering member 70 include white with excellent light reflectivity, black with excellent light absorption, and gray having both light reflectivity and light absorption. Also, the covering member 70 may have a plurality of resin layers laminated. Among them, considering the deterioration of the resin due to light absorption, it is preferable that the covering member 70 uses a white resin having light reflectivity at least on the outermost surface.

[0046] The light-emitting module 100 having the above configuration can be used, for example, as a light source for a vehicle headlight. At this time, for example, a configuration is adopted in which light is irradiated from the light source to the outside through a lens. The light-emitting module 100 turns on the light-emitting element 30 by an external power switch. Note that the light-emitting module 100 is configured so that part or all of the preset light-emitting elements 30 can be individually driven.

[0047] <Method for manufacturing a bonded substrate according to an embodiment> The method for manufacturing a bonded substrate according to the first embodiment includes performing a blasting process on the first surface 3A of the metal plate 3 using an abrasive having a median diameter of 15 μm or more and 50 μm or less, applying a first bonding material 5a containing silver on the first surface 3A of the metal plate 3, disposing a first ceramic 4 on the first surface 3A of the metal plate 3 via the first bonding material 5a, heating the first bonding material 5a to a temperature equal to or higher than the softening temperature of the first bonding material, preferably a temperature equal to or higher than the melting temperature, and bonding the metal plate 3 and the first ceramic 4 together. The bonding material may also represent at least one of the first bonding material and the second bonding material. According to the method for manufacturing a bonded substrate according to the first embodiment, the bonded substrate 1 of the present embodiment described below can be preferably manufactured.

[0048] The method for manufacturing a bonded substrate according to the second embodiment includes performing a blasting process on the first surface 3A and the second surface 3B opposite to the first surface 3A of the metal plate 3 using an abrasive having a median diameter of 15 μm or more and 50 μm or less, applying a first bonding material 5a containing silver and a second bonding material 7a on the first surface 3A and the second surface 3B of the metal plate 3, respectively, disposing a first ceramic 4 and a second ceramic 6 on the first surface 3A and the second surface 3B of the metal plate 3 via the first bonding material 5a and the second bonding material 7a, respectively, heating the first bonding material 5a and the second bonding material 7a to a temperature equal to or higher than the softening temperature of the first bonding material 5a and the second bonding material 7a, respectively, and bonding the metal plate 3 and the first ceramic 4, and the metal plate 3 and the second ceramic 6, together. According to the method for manufacturing a bonded substrate according to the second embodiment, the bonded substrate 2 of the present embodiment described below can be suitably manufactured.

[0049] FIG. 8 is a flowchart showing a method S1 for manufacturing a bonded substrate according to the first embodiment. FIG. 9 is a flowchart showing a method S2 for manufacturing a bonded substrate according to the second embodiment. FIGS. 10 to 14 are diagrams schematically showing an example of the manufacturing process of a method for manufacturing a light-emitting module according to the first embodiment. FIGS. 10 to 11 and FIGS. 15 to 18 are diagrams schematically showing an example of the manufacturing process of a method for manufacturing a light-emitting module according to the second embodiment. Specifically, FIGS. 14 to 18 are cross-sectional views illustrating the manufacturing process in the method for manufacturing a bonded substrate. In the description of the manufacturing method, "preparing" a member includes not only manufacturing the member but also acquiring the member, such as purchasing the member or receiving the member.

[0050] (Perform blasting treatment) In the first embodiment, in S10 of performing the blasting treatment, the first surface 3A of the metal plate 3 is subjected to blasting treatment using an abrasive having a median diameter of 15 μm or more and 50 μm or less (see FIGS. 10 to 11). Here, FIG. 10 shows the metal plate 3 before the blasting treatment. FIG. 11 shows the metal plate 3 after the blasting treatment is performed on the first surface 3A of the metal plate 3. The metal plate 3 after the blasting treatment has a central layer 3c of central crystal grains near the center in a cross-sectional view and a first layer 3a of first crystal grains having a median diameter smaller than that of the central crystal grains on the first surface 3A side.

[0051] In the second embodiment, in S15 of performing the blasting treatment, the first surface 3A of the metal plate 3 and the second surface 3B opposite to the first surface 3A are subjected to blasting treatment using an abrasive having a median diameter of 15 μm or more and 50 μm or less (see FIGS. 10 to 11 and FIG. 15).

[0052] FIG. 15 shows the metal plate 3 after the first surface 3A and the second surface 3B of the metal plate 3 are subjected to a blasting treatment. After the blasting treatment, the metal plate 3 has, in a cross-sectional view, a central layer 3c of central crystal grains near the center, a first layer 3a of first crystal grains having a median diameter smaller than that of the central crystal grains on the first surface 3A side, and a second layer 3b of second crystal grains having a median diameter smaller than that of the central crystal grains on the second surface 3B side.

[0053] The blasting treatment can be appropriately carried out using an abrasive having a median diameter of 15 μm or more and 50 μm or less and a known blasting treatment apparatus. Examples of the abrasive include aluminum oxide, zirconium oxide, steel, silica sand, slag, glass beads, etc., and aluminum oxide is preferred. The shape of the particles of the abrasive is substantially spherical (bead-like), cut wire-like, etc. The median diameter of the abrasive can be measured by a light transmission sedimentation method or a sedimentation test method conforming to the standard of JIS R6001-2, and is 15 μm or more and 50 μm or less, preferably 20 μm or more and 40 μm or less.

[0054] The blasting treatment is preferably carried out on the entire surface of the first surface 3A of the metal plate 3 in terms of efficiently reducing the diffusion of silver derived from the bonding material to the metal plate 3. When the second surface 3B is also subjected to the blasting treatment, it is preferably carried out on the entire surface of the second surface 3B of the metal plate 3. Therefore, it is preferable that the first layer 3a is provided on the entire surface on the first surface 3A side of the metal plate 3, and it is preferable that the second layer 3b is provided on the entire surface on the second surface 3B side of the metal plate 3.

[0055] The conditions of the blasting treatment can be appropriately selected according to the purpose. For example, the air pressure can be 0.1 MPa or more and 0.7 MPa or less, preferably 0.2 MPa or more and 0.5 MPa or less; the conveying speed of the metal plate 3 can be 5 mm / second or more and 20 mm / second or less.

[0056] On the first surface 3A of the metal plate 3 subjected to the blasting treatment, it is preferable that the number of crystal grains having an equivalent circle diameter larger than 350 μm is 10 grains / mm 2 or less, more preferably 5 grains / mm 2 or less, and even more preferably not included. On the second surface 3B of the blasted metal plate 3, there are 10 crystal grains with an equivalent circle diameter larger than 350 μm per mm 2 It is preferably the following, 5 grains / mm 2 The following is more preferable, and it is even more preferable not to contain it.

[0057] In the cross-sectional view of the manufactured bonded substrate 1 or the metal plate 3 in the manufacturing process, the metal plate 3 has a central layer 3c of central crystal grains near the center and a first layer 3a of first crystal grains with an equivalent circle diameter smaller than that of the central crystal grains on the first surface 3A side. Here, since the first layer 3a is very thin and it is difficult to evaluate the equivalent circle diameter in the cross-sectional view of the metal plate 3, the evaluation can be performed by the following procedure using the first surface 3A of the metal plate 3 or the surface obtained by etching the first surface 3A of the metal plate 3. For reference, it will be described with reference to FIGS. 23 to 26 in the examples described later. FIGS. 23 to 26 are diagrams for explaining the method of measuring the equivalent circle diameter of crystal grains on the observation surface of the metal plate.

[0058] [Method for measuring and evaluating equivalent circle diameter] Using a microscope (manufactured by KEYENCE CORPORATION, VHX-8000), take a 100-fold photograph of the observation surface (object to be evaluated). Paste the taken photograph into PowerPoint (Microsoft) etc., and use a graphic tool to mark the area surrounded by grain boundaries from above the photograph so that it can be treated as an independent particle (see FIG. 23). Delete the photograph (see FIG. 24), adjust the position so that the particles in the marked image do not overlap, fill the surrounded area with black, and save it in a format such as jpeg or bmp (see FIG. 25). By using the image analysis software Image J for analysis, the value of the area of each particle can be obtained (see FIG. 26). In order to match the scale of the photograph, convert from pixels to the actual length [μm]. Using the following formula, obtain the equivalent circle diameter (diameter when the area is considered as a perfect circle). Formula: L = √4S / π L: Equivalent circle diameter of the particle [μm] S: Area of the particle [μm 2 ​

[0059] Perform the method for measuring the equivalent circle diameter using the first surface 3A of the metal plate 3 or the surface obtained by etching a predetermined thickness from the first surface 3A of the metal plate 3 as the observation surface, detect the presence or absence of crystal grains having an equivalent circle diameter larger than 350 μm, and for every 1 mm 2 (for example, per 1 mm × 1 mm observation field), if the number of crystal grains having an equivalent circle diameter larger than 350 μm is 10 or less (that is, 10 grains / mm 2 or less), it can be evaluated as the first layer 3a, and the thickness of the first layer 3a can be obtained. Regarding the second surface 3B of the metal plate 3 as well, in the same manner, it can be evaluated as the second layer 3b, and the thickness of the second layer 3b can be obtained.

[0060] On the other hand, a region where the number of crystal grains having an equivalent circle diameter larger than 350 μm exceeds 10 grains / mm 2 is defined as the central layer 3c. When measuring the equivalent circle diameter of the central crystal grains in the central layer 3c, it can be obtained by cutting out a plane that is substantially at the center of the central layer 3c and is horizontal with the first surface 3A of the metal plate 3 by etching or the like, using this as the observation surface, and performing the method for measuring the equivalent circle diameter. The average equivalent circle diameter of the central crystal grains is preferably 200 μm or more and 800 μm or less, and more preferably 200 μm or more and 600 μm or less.

[0061] (Applying a bonding material) In the first embodiment, in S20 of applying a bonding material, a first bonding material 5a containing silver is applied on the first surface 3A of the metal plate 3 after the blasting treatment (see FIGS. 11 and 12).

[0062] In the second embodiment, in S25 of applying a bonding material, a first bonding material 5a containing silver and a second bonding material 7a are respectively applied on the first surface 3A and the second surface 3B of the metal plate 3 after the blasting treatment (see FIGS. 15 to 16). The first bonding material 5a and the second bonding material 7a can be disposed, for example, by screen printing, metal mask printing, or injection from the nozzle of a dispenser.

[0063] The first bonding material 5a is a member containing metal and having fluidity, and is preferably an active metal brazing material. The first bonding material 5a can be applied and arranged so as to adhere to the surface of the first surface 4A. The first bonding material 5a is preferably arranged to have a uniform thickness from the first surface 4A. Note that the first bonding material 5a becomes the first metal body 5 by firing.

[0064] The first bonding material 5a preferably contains an alloy containing silver and copper, and more preferably further contains at least one selected from copper, a copper-zinc alloy, and a copper-tin alloy. The alloy containing silver and copper is preferable in that it can be fired at a relatively low temperature such as 780 °C or higher and 850 °C or lower. Also, a conductive paste containing metal nanoparticles having a median diameter of 10 nm or more and 500 nm or less, metal particles having a median diameter of 1 μm or more and 10 μm or less, and a resin may be used, and the metal plate 3 and the first ceramic 4 or the second ceramic 6 may be joined by heating and pressurizing. Here, silver powder, copper powder, etc. can be used as the metal nanoparticles and metal particles, and heating can be performed at 200 °C or higher and 300 °C or lower, and pressurization can be performed at 2 MPa or higher and 20 MPa or lower. According to the method for manufacturing the bonded substrate of the present embodiment, a bonding material containing an alloy containing silver and copper can be preferably used in that it can reduce the diffusion of silver derived from the bonding material into the metal plate. Note that the median diameter is the 50% particle size (D50) in the volume-based particle size distribution, and specifically, it refers to the particle size (volume median diameter) at which the volume cumulative frequency from the small-diameter side in the volume-based particle size distribution measured by the laser diffraction scattering method reaches 50%. The laser diffraction scattering method can be measured, for example, using a laser diffraction particle size distribution measuring device (product name: MASTER SIZER3000, manufactured by MALVERN).

[0065] The first bonding material 5a further contains an activating metal of 15% by mass or less of the entire first bonding material 5a, and the activating metal preferably contains at least one of the metals Ti, Ce, Zr, and Mg. The first bonding material 5a preferably contains an active metal powder. The active metal powder can be at least one selected from TiH2, CeH2, ZrH2, and MgH2. Among these, TiH2 is preferred. By containing TiH2, it reacts with nitrogen contained in the first ceramic 4 to form a metal compound layer such as TiN as a reaction layer at the interface with the first ceramic 4. Thereby, the adhesion between the first metal body 5 formed by firing the first bonding material 5a and the first ceramic 4 is improved, and it firmly adheres to the first surface 4A.

[0066] The first bonding material 5a may contain an organic binder. The viscosity of the first bonding material 5a can be adjusted by the type and amount of the organic binder. As the organic binder, for example, solvents, acrylics, epoxies, urethanes, ethyl cellulose, silicones, phenols, polyimides, polyurethanes, melamines, ureas, and other resin materials generally used as conductive pastes may be used. Note that the organic binder is decomposed by firing described later and evaporated and removed.

[0067] The first bonding material 5a may contain an inorganic filler other than metal. By containing the inorganic filler, the volume shrinkage during firing of the first bonding material 5a can be reduced. As the inorganic filler, for example, AlN, Si3N4, etc. can be used. In terms of mass% with respect to the total amount of the first bonding material 5a, the content of the alloy containing silver and copper is preferably 85 mass% or more, the content of TiH2 as the metal active powder is preferably 0.5 mass% or more and 10 mass% or less, the content of the organic binder is preferably 0.1 mass% or more and 10 mass% or less, and the content of the inorganic filler is preferably 1 mass% or more and 20 mass% or less.

[0068] The second bonding material 7a is a member containing metal and having fluidity, and is preferably an active metal brazing material. The second bonding material 7a may be applied and disposed on the first surface 6A of the second ceramic 6, or may be applied and disposed on the second surface 3B of the metal plate 3, and can be appropriately selected. The second bonding material 7a may be the same as or different from the first bonding material 5a. For each component and the like of the second bonding material 7a, the matters described for the first bonding material 5a can be appropriately selected.

[0069] (Placing the first ceramic) In the first embodiment, in S30 of placing the first ceramic, the first ceramic 4 is placed on the first surface 3A of the metal plate 3 via the first bonding material 5a (see FIG. 13). Thereby, a laminate before firing for manufacturing the bonded substrate 1 can be obtained. In another aspect, the first bonding material 5a may be applied on the first surface 4A of the first ceramic 4, and the first ceramic 4 may be placed on the first surface 3A of the metal plate 3 via the first bonding material 5a.

[0070] In the second embodiment, in S35 of placing the first ceramic and the second ceramic, as shown in FIG. 17, the first ceramic 4 and the second ceramic 6 are placed on the first surface 3A and the second surface 3B of the metal plate 3 via the first bonding material 5a and the second bonding material 7a. Thereby, a laminate before firing for manufacturing the bonded substrate 2 can be obtained. In another aspect, the second bonding material 7a may be applied on the first surface 6A of the second ceramic 6, and the second ceramic 6 may be placed on the second surface 3B of the metal plate 3 via the second bonding material 7a.

[0071] (Bonding) In the first embodiment, in S40 of bonding, the first bonding material 5a is heated to a temperature equal to or higher than the softening temperature of the first bonding material 5a, preferably equal to or higher than the melting temperature, and the metal plate 3 and the first ceramic 4 are bonded together (see FIGS. 13 to 14). Thereby, the first bonding material 5a is fired to obtain the first metal body 5, and the bonded substrate 1 can be manufactured.

[0072] In the second embodiment, the bonding S45 is performed by heating the first bonding material 5a and the second bonding material 7a to a temperature equal to or higher than the softening temperature, preferably the melting temperature, of the first bonding material 5a and the second bonding material 7a, and bonding the metal plate 3 and the first ceramic 4, and the metal plate 3 and the second ceramic 6 (see FIGS. 17 to 18). Thereby, the first bonding material 5a and the second bonding material 7a are fired to obtain the first metal body 5 and the second metal body 7 respectively, and the bonded substrate 2 can be manufactured.

[0073] The softening temperature of the first bonding material 5a and the second bonding material 7a is preferably 700 °C or higher and 1000 °C or lower. The heating temperature is equal to or higher than the softening temperature of the first bonding material 5a and the second bonding material 7a, and can be 700 °C or higher and 1200 °C or lower, preferably 800 °C or higher and 1100 °C or lower. The heating atmosphere is preferably a vacuum atmosphere of 10 -5 Pa or less or an Ar atmosphere of 99.9% or more.

[0074] By firing the first bonding material 5a and the second bonding material 7a, the organic solvent is decomposed and volatilized and removed. By removing the organic solvent, the volumes of the first metal body 5 and the second metal body 7 shrink with respect to the volumes of the first bonding material 5a and the second bonding material 7a. In order to prevent deformation of the first metal body 5 and the second metal body 7 and peeling from the first ceramic 4 and the second ceramic 6 in the obtained fired laminate due to this shrinkage, and to reduce warping of the first ceramic 4 and the second ceramic 6, it is preferable to perform pressure firing. The pressure can be, for example, 0.025 kg / cm in the stacking direction so that the pressure applied to the laminate is uniform 2 or more and 0.5 kg / cm 2 or less.

[0075] By the heating, the first bonding material 5a becomes the first metal body 5, and in a cross-sectional view, it is preferable that a metal compound layer containing a metal compound is formed in the vicinity of the interface between the first metal body 5 and the first ceramic 4 and in the vicinity of the interface between the first metal body 5 and the metal plate 3. Further, by the heating, the second bonding material 7a becomes the second metal body 7, and in a cross-sectional view, it is preferable that a metal compound layer containing a metal compound is formed in the vicinity of the interface between the second metal body 7 and the second ceramic 6 and in the vicinity of the interface between the second metal body 7 and the metal plate 3.

[0076] By heating, a metal compound layer containing a reaction product of a non-metal element contained in the first ceramic 4 and the second ceramic 6 and an active metal element contained in the first bonding material 5a and the second bonding material 7a is formed respectively. That is, the first metal body 5 has a metal compound layer that changes from the active metal powder at the interface between the first ceramic 4 and the first metal body 5. When having the second metal body 7, the second metal body 7 has a metal compound layer that changes from the active metal powder at the interface between the second ceramic 6 and the second metal body 7. Here, it is preferable that the metal compound layer contains TiN which is a reaction product of nitrogen contained in the first ceramic 4 and the second ceramic 6 and TiH2 contained in the active metal powder of the first bonding material 5a and the second bonding material 7a. The first ceramic 4 and the first metal body 5, and the second ceramic 6 and the second metal body 7 can all enhance the bonding reliability by having a metal compound layer at the interface.

[0077] In addition to obtaining excellent adhesion between the first ceramic 4 and the first metal body 5 by firing, between the first layer 3a of the metal plate 3 and the first metal body 5, by refining the crystal structure of the surface of the metal plate, the diffusion of the metal derived from the first metal body 5 can be reduced, the generation of internal cracks in the bonded substrate can be reduced, and a bonded substrate with excellent thermal conductivity can be manufactured.

[0078] The manufacturing method of the bonded substrate of the present embodiment may further include polishing or grinding, plating, cutting, etc. the obtained fired laminate.

[0079] The manufacturing method of the bonded substrate having the above configuration can, in particular, refine the crystal structure of the surface of the metal plate by performing a blasting treatment on the surface of the metal plate, reduce the diffusion of the metal derived from the metal body, reduce the generation of internal cracks in the bonded substrate, and manufacture a bonded substrate with excellent thermal conductivity.

[0080] <Method for manufacturing a light-emitting module according to an embodiment> The method for manufacturing a light-emitting module according to the embodiment includes manufacturing a bonded substrate by the method for manufacturing a bonded substrate according to the above-described embodiment (S1 or S2), and disposing a light-emitting element on the bonded substrate.

[0081] (Disposing the light-emitting element) For S3 of disposing the light-emitting element, the light-emitting element may be disposed on the bonded substrate, and a conventionally known method can be appropriately selected. For example, it may be after the manufacture of the bonded substrate, or the light-emitting element may be disposed during the manufacturing process of the bonded substrate.

[0082] As described above, the preferred embodiments and the like have been described in detail, but the present invention is not limited to the above-described embodiments and the like, and various modifications and substitutions can be made to the above-described embodiments and the like without departing from the scope described in the claims.

Example

[0083] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples.

[0084] (Example 1) For each of a copper plate (tough pitch copper, size: 54 mm × 54 mm, average thickness 0.5 mm) as a metal plate and a ceramic (size: 54 mm × 54 mm, average thickness 320 μm) as a first ceramic, alumina beads with a median diameter of 23 μm were used for blasting at a pressure of 0.3 MPa and a work conveyance speed of 10 mm / second to 15 mm / second. An Ag-Cu eutectic brazing material (5 parts by mass of TiH2, 0.5 parts by mass of polyvinyl acetal resin, 0.5 parts by mass of lauric acid, 9 parts by mass of terpineol with respect to 100 parts by mass of Ag-Cu eutectic powder) as a bonding material was applied to each blasted surface of the copper plate and the ceramic, and after drying the solvent, the bonding materials of the copper plate and the ceramic were bonded together, and vacuum firing was performed at 830°C to manufacture the bonded substrate of Example 1.

[0085] (Comparative Example 1) In Comparative Example 1, a bonded substrate of Comparative Example 1 was produced in the same manner as in Example 1, except that the blasting treatment was not performed.

[0086] [Observation with Electron Microscope] The cross-sections of the bonded substrates of Example 1 and Comparative Example 1 obtained, and their elemental distributions were observed by reflection electron images and elemental mapping by SEM-EDS using an electron microscope (manufactured by Hitachi High-Tech Corporation, apparatus name: Miniscope TM4000PlusII). The results of Example 1 are shown in Fig. 19, and the results of Comparative Example 1 are shown in Fig. 20. In Figs. 19 and 20, the upper part shows the electron microscope images, and the middle and lower parts show the elemental distribution images by characteristic X-rays of copper Cu (left in the middle), silicon Si (right in the middle), silver Ag (left in the lower part), and titanium Ti (right in the lower part), respectively. In Comparative Example 1 where the blasting treatment was not performed, it was confirmed that an active metal layer (Ag-Cu-Ti) in which the bonding material and copper were alloyed was formed at the interface between the copper plate and the ceramics. Here, it was confirmed that Ag was diffused to a depth of approximately 100 μm of the copper plate. On the other hand, in Example 1 where the blasting treatment was performed, although an active metal layer (Ag-Cu-Ti) was formed at the interface between the copper plate and the ceramics, compared with Comparative Example 1, the diffusion of Ag was suppressed, and it was found that both the diffusion depth into the copper plate and the amount of Ag were reduced.

[0087] [Crack Evaluation] The presence or absence of internal cracks in the obtained bonded substrates of Example 1 and Comparative Example 1 was evaluated by observing the SEM images of the cross-sections of each bonded substrate using an electron microscope (manufactured by Hitachi High-Tech Corporation, apparatus name: Miniscope TM4000PlusII). In Comparative Example 1 where the blasting treatment was not performed, it was confirmed that cracks occurred at the interface between the copper plate and the ceramics, but in Example 1 where the blasting treatment was performed, no internal cracks were observed.

[0088] [Evaluation of Metal Plate] To analyze the difference between Example 1 with blast treatment and Comparative Example 1 without blast treatment regarding the surface structure of the metal plate of the bonding substrate, a copper plate before firing having a region with blast treatment (right side) in Example 1 and a region without blast treatment (left side) in Comparative Example 1 was fabricated (see Fig. 21). Next, the copper plates of Example 1 and Comparative Example 1 were subjected to vacuum firing at 830 °C to fabricate fired copper plates (see Fig. 22). From the observations in Figs. 21 to 22, in Comparative Example 1 (left side) without blast treatment, crystal grains with a large crystal size could be visually confirmed due to the firing of the copper plate. On the other hand, in Example 1 (right side) with blast treatment, even after firing the copper plate, crystal grains with a large crystal size could not be visually confirmed.

[0089] To quantitatively analyze the size of the crystal grains, the equivalent circle diameter of the crystal grains was measured by the following method. Figs. 23 to 26 show diagrams for explaining the method of measuring the equivalent circle diameter of crystal grains on the observation surface of the metal plate. Figs. 23 to 26 show examples of measuring the equivalent circle diameter in the region without blast treatment (Comparative Example 1) of Fig. 22.

[0090] [Method for Measuring and Evaluating Equivalent Circle Diameter] Specifically, using a microscope (manufactured by Keyence Corporation, VHX-8000), a 100-fold photograph of the observation surface (object to be evaluated) was taken. The taken photograph was pasted into PowerPoint (Microsoft), and using a drawing tool, marking was performed so that the areas surrounded by grain boundaries could be treated as independent particles from above the photograph (see Fig. 23). The photograph was deleted (see Fig. 24), the positions were adjusted so that the particles in the marked image did not overlap, the surrounded areas were filled in black, and saved in the jpeg format (see Fig. 25). By using the image analysis software Image J for analysis, the area values of each particle were obtained (see Fig. 26). For matching the scale of the photograph, conversion from pixels to the actual length [μm] was performed. Using the following formula, the equivalent circle diameter (diameter when the area is considered as a perfect circle) was obtained. Formula: L = √4S / π L: Equivalent circle diameter of particles [μm] S: Area of particles [μm 2

[0091] Fig. 27 shows the measurement results of the equivalent circle diameter of Comparative Example 1. In Fig. 27, the horizontal axis indicates intervals of equivalent circle diameter of 200 μm or less, more than 200 μm and 350 μm or less, more than 350 μm and 500 μm or less, more than 500 μm and 650 μm or less, more than 650 μm and 800 μm or less, more than 800 μm and 900 μm or less, and more than 900 μm, and the vertical axis indicates the frequency (number) of particles corresponding to each interval of the equivalent circle diameter. As a result, without performing the blasting treatment in Comparative Example 1, the average equivalent circle diameter of the crystal grains on the first surface (surface) of the fired metal plate was 397.9 μm, the maximum equivalent circle diameter was 1256.2 μm, and the minimum equivalent circle diameter was 151.8 μm.

[0092] Similarly, the equivalent circle diameter was measured for the region (Example 1) where the blasting treatment of Fig. 22 was performed. As a result, no crystal grains with an equivalent circle diameter larger than 350 μm were detected.

[0093] From the results of the analysis of FIGS. 19 to 27 above, in Example 1, by performing the blasting treatment on the metal plate, the size of the crystal grains on the first surface of the metal plate becomes smaller, no crystal grains with an equivalent circle diameter larger than 350 μm are detected, and the diffusion of Ag at the interface between the copper plate and the ceramics is suppressed, and it was found that the generation of internal cracks is reduced.

[0094] In addition to the above embodiments, the following additional remarks are further disclosed. (Additional Remark 1) Performing a blasting treatment on the first surface of the metal plate using an abrasive having a median diameter of 15 μm or more and 50 μm or less, Applying a bonding material containing silver on the first surface of the metal plate, Disposing a first ceramic on the first surface of the metal plate via the bonding material, Heating the bonding material to a temperature equal to or higher than the softening temperature of the bonding material and bonding the metal plate and the first ceramic, a method for manufacturing a bonded substrate. (Additional Remark 2)​ Performing a blasting treatment on the first surface of the metal plate and the second surface opposite to the first surface using an abrasive having a median diameter of 15 μm or more and 50 μm or less; Applying the bonding material containing silver on the first surface and the second surface of the metal plate; Disposing the first ceramic and the second ceramic on the first surface and the second surface of the metal plate via the bonding material, respectively; Heating the bonding material to a temperature equal to or higher than the softening temperature of the bonding material, and bonding the metal plate and the first ceramic, and the metal plate and the second ceramic, which is the method for manufacturing the bonded substrate according to Addendum 1. (Addendum 3) The bonding material includes an alloy containing silver and copper, The content of the alloy is 85% by mass or more of the entire bonding material, which is the method for manufacturing the bonded substrate according to Addendum 1 or 2. (Addendum 4) The bonding material further includes an activating metal of 15% by mass or less of the entire bonding material, The activating metal includes at least one metal selected from Ti, Ce, Zr, and Mg, which is the method for manufacturing the bonded substrate according to Addendum 3. (Addendum 5) The melting point of the alloy is 700 °C or higher and 1200 °C or lower, which is the method for manufacturing the bonded substrate according to Addendum 3. (Addendum 6) The bonding material further includes at least one selected from copper, copper-zinc alloy, and copper-tin alloy, which is the method for manufacturing the bonded substrate according to Addendum 3. (Addendum 7) The bonding material further includes at least one of an organic binder and a resin, which is the method for manufacturing the bonded substrate according to Addendum 3. (Addendum 8) On the first surface of the metal plate subjected to the blasting treatment, the number of crystal grains having an equivalent circle diameter larger than 350 μm is 10 grains / mm 2 or less, which is the method for manufacturing the bonded substrate according to any one of Addenda 1 to 7. (Addendum 9) On the second surface of the metal plate that has undergone the blasting treatment, there are 10 crystal grains with an equivalent circle diameter larger than 350 μm per mm 2 The method for manufacturing a bonded substrate according to Supplementary Note 2, which is as follows. (Supplementary Note 10) The method for manufacturing a bonded substrate according to any one of Supplementary Notes 1 to 9, wherein the first ceramic is at least one selected from silicon nitride, aluminum nitride, boron nitride, aluminum oxide, and silicon carbide. (Supplementary Note 11) The method for manufacturing a bonded substrate according to any one of Supplementary Notes 1 to 10, wherein the metal plate is copper. (Supplementary Note 12) The method for manufacturing a bonded substrate according to any one of Supplementary Notes 1 to 11, wherein the softening temperature of the bonding material is 700 °C or higher and 1000 °C or lower. (Supplementary Note 13) When bonding the metal plate and the first ceramic, the bonding material becomes a metal body by the heating, and in a cross-sectional view, a metal compound layer containing a metal compound is formed near the interface between the metal body and the first ceramic and near the interface between the metal body and the metal plate. The method for manufacturing a bonded substrate according to any one of Supplementary Notes 1 to 12. (Supplementary Note 14) A metal plate having a first surface and a second surface opposite to the first surface, A first ceramic, A metal body containing silver, which is disposed between the first surface of the metal plate and the first ceramic, A bonded substrate having, in a cross-sectional view, a central layer of central crystal grains near the center of the metal plate and a first layer of first crystal grains having an equivalent circle diameter smaller than that of the central crystal grains on the first surface side. (Supplementary Note 15) A second ceramic, A metal body containing silver, which is disposed between the second surface of the metal plate and the second ceramic, and further having In a cross-sectional view, a second layer of second crystal grains having an equivalent circle diameter smaller than that of the central crystal grains on the second surface side. The bonded substrate according to Supplementary Note 14. (Supplementary Note 16) The equivalent average circle diameter of the central crystal grains is 200 μm or more and 600 μm or less, and the bonded substrate according to Appendix 14 or 15. (Appendix 17) On the first surface of the metal plate, the number of crystal grains having an equivalent circle diameter of more than 350 μm is 10 grains / mm 2 or less, and the bonded substrate according to Appendix 14 or 15. (Appendix 18) On the second surface of the metal plate, the number of crystal grains having an equivalent circle diameter of more than 350 μm is 10 grains / mm 2 or less, and the bonded substrate according to Appendix 15. (Appendix 19) In a cross-sectional view, the average thickness of the first layer is 0.05 μm or more and 10 μm or less, and the bonded substrate according to any one of Appendices 14 to 17. (Appendix 20) The metal body contains silver and copper, and the total content of silver and copper is 85% by mass or more of the entire metal body, and the bonded substrate according to any one of Appendices 14 to 19. (Appendix 21) The metal body further contains a metal compound of 15% by mass or less of the entire metal body, and the metal compound is a compound containing at least one metal of Ti, Ce, Zr, and Mg, and the bonded substrate according to any one of Appendices 14 to 20. (Appendix 22) In a cross-sectional view, the metal body has a metal compound layer containing the metal compound formed near the interface between the metal body and the first ceramic and near the interface between the metal body and the metal plate, and the bonded substrate according to Appendix 21. (Appendix 23) The first surface of the metal plate has a surface roughness Ra of 0.3 μm or more and 6 μm or less, and the bonded substrate according to any one of Appendices 14 to 22. (Appendix 24) A light-emitting module comprising the bonded substrate according to any one of Appendices 14 to 23, and a plurality of light-emitting elements disposed on the bonded substrate.

Explanation of Signs

[0095] 1 Bonding substrate 2 Bonding substrate 3 Metal plate 3a First layer (metal plate) 3b Second layer (metal plate) 3c Central layer (metal plate) 3A First surface 3B Second surface 4 First ceramics 4A First surface 4B Second surface 5 First metal body 5a First bonding material 6 Second ceramics 6A First surface 6B Second surface 7 Second metal body 7a Second bonding material 10 First substrate 10a Upper surface 10r Element mounting area 11 First terminal 20 Second substrate 20a Upper surface 20r Substrate mounting area 22 Second terminal 25 Conductive paste 30 Light-emitting element 40 Wire 40t Top 50 First frame part 60 Second frame part 70 Coating member 70t Top 80 Translucent member 90 Reflective member 100 Light-emitting module

Claims

1. performing a blasting process on a first surface of a metal plate using an abrasive having a median diameter of 15 μm or more and 50 μm or less; applying a bonding material containing silver onto the first surface of the metal plate; disposing a first ceramic via the bonding material on the first surface of the metal plate; heating the bonding material to a temperature equal to or higher than the softening temperature of the bonding material to bond the metal plate and the first ceramic, the method for manufacturing a bonded substrate including the above steps.

2. performing a blasting process on a first surface and a second surface opposite to the first surface of the metal plate using an abrasive having a median diameter of 15 μm or more and 50 μm or less; applying the bonding material containing silver onto the first surface and the second surface of the metal plate; disposing the first ceramic and a second ceramic via the bonding material on the first surface and the second surface of the metal plate, respectively; heating the bonding material to a temperature equal to or higher than the softening temperature of the bonding material to bond the metal plate and the first ceramic, and the metal plate and the second ceramic, the method for manufacturing a bonded substrate according to Claim 1 including the above steps.

3. the bonding material includes an alloy containing silver and copper, the content of the alloy is 85% by mass or more of the entire bonding material, the method for manufacturing a bonded substrate according to Claim 1 or 2.

4. the bonding material further includes an activating metal of 15% by mass or less of the entire bonding material, the activating metal includes at least one metal selected from Ti, Ce, Zr, and Mg, the method for manufacturing a bonded substrate according to Claim 3.

5. the melting point of the alloy is 700°C or more and 1200°C or less, the method for manufacturing a bonded substrate according to Claim 3.

6. the bonding material further includes at least one selected from copper, a copper-zinc alloy, and a copper-tin alloy, the method for manufacturing a bonded substrate according to Claim 3.

7. the bonding material further includes at least one of an organic binder and a resin, the method for manufacturing a bonded substrate according to Claim 3.

8. On the first surface of the metal plate that has been subjected to the blasting treatment, the number of crystal grains having an equivalent circle diameter of more than 350 μm is 10 grains / mm ２ The method for manufacturing a bonded substrate according to claim 1, which is as follows.

9. On the second surface of the metal plate that has been subjected to the blasting treatment, the number of crystal grains having an equivalent circle diameter larger than 350 μm is 10 grains / mm ２ The method for manufacturing a bonded substrate according to claim 2, which is as follows.

10. the first ceramic is at least one selected from silicon nitride, aluminum nitride, boron nitride, aluminum oxide, and silicon carbide, the method for manufacturing a bonded substrate according to Claim 1 or 2.

11. the metal plate is copper, the method for manufacturing a bonded substrate according to Claim 1 or 2.

12. The manufacturing method of the bonded substrate according to claim 1 or 2, wherein the softening temperature of the bonding material is 700°C or higher and 1000°C or lower.

13. In bonding the metal plate and the first ceramic, by the heating, the bonding material becomes a metal body, and in a cross-sectional view, a metal compound layer containing a metal compound is formed in the vicinity of the interface between the metal body and the first ceramic and in the vicinity of the interface between the metal body and the metal plate. The manufacturing method of the bonded substrate according to claim 1 or 2.

14. A metal plate having a first surface and a second surface opposite to the first surface, A first ceramic, A metal body containing silver, disposed between the first surface of the metal plate and the first ceramic, and having In a cross-sectional view, a bonded substrate having a central layer of central crystal grains near the center of the metal plate and a first layer of first crystal grains having a circular equivalent diameter smaller than that of the central crystal grains on the first surface side.

15. A second ceramic, A metal body containing silver, further disposed between the second surface of the metal plate and the second ceramic, and having In a cross-sectional view, further having a second layer of second crystal grains having a circular equivalent diameter smaller than that of the central crystal grains on the second surface side. The bonded substrate according to claim 14.

16. The average circular equivalent diameter of the central crystal grains is 200 μm or more and 600 μm or less. The bonded substrate according to claim 14 or 15.

17. On the first surface of the metal plate, the number of crystal grains having an equivalent circle diameter larger than 350 μm is 10 grains / mm ２ The bonded substrate according to claim 14 or 15, wherein the above is satisfied.

18. On the second surface of the metal plate, the number of crystal grains having an equivalent circle diameter larger than 350 μm is 10 grains / mm ２ The bonded substrate according to claim 15, wherein the above is satisfied.

19. In a cross-sectional view, the average thickness of the first layer is 0.05 μm or more and 10 μm or less. The bonded substrate according to claim 14 or 15.

20. The metal body contains silver and copper, The total content of silver and copper is 85% by mass or more of the entire metal body. The bonded substrate according to claim 14 or 15.

21. The metal body further contains a metal compound of 15% by mass or less of the entire metal body, The metal compound is a compound containing at least one metal of Ti, Ce, Zr, and Mg. The bonded substrate according to claim 14 or 15.

22. In a cross-sectional view, a metal compound layer containing the metal compound is formed in the vicinity of the interface between the metal body and the first ceramic and in the vicinity of the interface between the metal body and the metal plate. The bonded substrate according to claim 21.

23. The first surface of the metal plate has a surface roughness Ra of 0.3 μm or more and 6 μm or less. The bonded substrate according to claim 14 or 15.

24. The bonded substrate according to claim 14 or 15, and A light-emitting module comprising: a plurality of light-emitting elements disposed on the bonding substrate.

Images