Ceramic substrates and light-emitting devices, and methods for manufacturing the same.

Abstract

To provide ceramic substrates and light-emitting devices, as well as methods for manufacturing them, that allow for a constant distance between adjacent through-holes and offer a high degree of design flexibility. [Solution] A method for manufacturing a ceramic substrate 100 according to one embodiment of the present disclosure includes: preparing a ceramic plate 1 having a first surface 1a and a second surface 1b opposite to the first surface, having a through hole 2 connecting the first surface 1a and the second surface 1b, wherein the maximum diameter of the second opening 2b of the through hole 2 formed on the second surface 1b is less than 0.90 times the maximum diameter of the first opening 2a of the through hole 2 formed on the first surface 1a; arranging a covering member 10 so as to cover the first opening 2a of the through hole 2 formed on the first surface 1a; bringing the inner surface defining the through hole 2 of the ceramic plate 1 on which the covering member 10 is arranged into contact with a first etching solution; and peeling the covering member 10 from the first surface 1a.

Description

[Technical Field]

[0001] This disclosure relates to ceramic substrates and light-emitting devices, as well as methods for manufacturing the same. [Background technology]

[0002] In recent years, in order to miniaturize, enhance the functionality, and integrate electronic devices and components, substrates have been proposed in which through-holes (also called "holes" or "vias") are formed in an insulating substrate, and conductive materials such as copper and silver are placed in the through-holes to electrically connect both sides of the substrate. One method for forming such through-holes in an insulating substrate is to irradiate it with a high-power laser.

[0003] It is known that through-holes in an insulating substrate formed by laser irradiation have a tapered shape in cross-section in the thickness direction of the insulating substrate, with the diameter of the opening of the through-hole decreasing in the direction of laser irradiation (see Patent Document 1).

[0004] Furthermore, a method is known in which through holes are created in a ceramic green sheet using a laser, a metal material is embedded in the through holes, and then the ceramic green sheet and the metal material are fired simultaneously (see Patent Document 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-13766 [Patent Document 2] Japanese Patent Publication No. 2015-162575 [Overview of the project] [Problems that the invention aims to solve]

[0006] The present disclosure aims to provide ceramic substrates and light-emitting devices, as well as methods for manufacturing them, which allow for a constant distance between adjacent through-holes and offer a high degree of design flexibility. [Means for solving the problem]

[0007] A method for manufacturing a ceramic substrate according to one embodiment of the present disclosure includes: preparing a ceramic plate having a first surface and a second surface opposite to the first surface, having a through hole connecting the first surface and the second surface, wherein the maximum diameter of the second opening of the through hole formed on the second surface is less than 0.90 times the maximum diameter of the first opening of the through hole formed on the first surface; arranging a covering member so as to cover the first opening of the through hole formed on the first surface; bringing the inner surface defining the through hole of the ceramic plate on which the covering member is arranged into contact with a first etching solution; and peeling the covering member from the first surface.

[0008] Furthermore, a method for manufacturing a light-emitting device according to one embodiment of the present disclosure includes preparing a ceramic substrate manufactured by a method for manufacturing a ceramic substrate, and arranging a light-emitting element equipped with electrodes on the ceramic substrate.

[0009] Furthermore, a ceramic substrate according to one embodiment of the present disclosure is a ceramic substrate having a first surface and a second surface opposite to the first surface, and having a through hole connecting the first surface and the second surface, wherein the maximum diameter of the first opening of the through hole on the first surface is 80 μm or more and 300 μm or less, the maximum diameter of the second opening of the through hole on the second surface is 0.90 times or more and 1.10 times the maximum diameter of the first opening of the through hole on the first surface, and the arithmetic mean roughness Ra of the inner surface defining the through hole is 5 μm or less.

[0010] Furthermore, a light-emitting device according to one embodiment of the present disclosure comprises a ceramic substrate according to one embodiment of the present disclosure, and a light-emitting element equipped with electrodes, which is disposed on the ceramic substrate. [Effects of the Invention]

[0011] According to an embodiment of the present disclosure, it is possible to provide a ceramic substrate, a light-emitting device, and a method for manufacturing them, which can make the distance between adjacent through-holes constant and have a high degree of design freedom.

Brief Description of the Drawings

[0012] [Figure 1] It is a flowchart showing an example of a method for manufacturing a ceramic substrate according to the first embodiment. [Figure 2A] It is a schematic cross-sectional view showing an example of a ceramic plate used in the method for manufacturing a ceramic substrate according to the first embodiment. [Figure 2B] It is a schematic top view of the ceramic plate of FIG. 2A. [Figure 2C] It is a schematic bottom view of the ceramic plate of FIG. 2A. [Figure 3] It is a schematic cross-sectional view showing an example of arranging a coating member in the method for manufacturing a ceramic substrate according to the first embodiment. [Figure 4] It is a schematic cross-sectional view showing an example of contacting in the method for manufacturing a ceramic substrate according to the first embodiment. [Figure 5A] It is a schematic cross-sectional view showing an example of peeling in the method for manufacturing a ceramic substrate according to the first embodiment. [Figure 5B] It is a schematic top view of the ceramic substrate of FIG. 5A. [Figure 5C] It is a schematic bottom view of the ceramic substrate of FIG. 5A. [Figure 5D] It is a schematic cross-sectional view taken along the VD-VD line of FIG. 5A. [Figure 6] It is a flowchart showing an example of plating in the method for manufacturing a ceramic substrate according to the third embodiment. [Figure 7] In the plating in the method for manufacturing a ceramic substrate according to the third embodiment, it is a schematic cross-sectional view showing an example of arranging an underlying metal. [Figure 8] It is a schematic cross-sectional view showing an example of plating in the method for manufacturing a ceramic substrate according to the third embodiment. [Figure 9] It is a flowchart showing an example of preparing a ceramic plate in the manufacturing method of the ceramic substrate according to the fourth embodiment. [Figure 10] It is a schematic cross-sectional view showing an example of preparing a ceramic plate without through holes in the manufacturing method of the ceramic substrate according to the fourth embodiment. [Figure 11A] It is a schematic cross-sectional view showing an example of forming through holes in the manufacturing method of the ceramic substrate according to the fourth embodiment. [Figure 11B] It is a schematic top view of the ceramic plate of FIG. 11A. [Figure 11C] It is a schematic bottom view of the ceramic plate of FIG. 11A. [Figure 12] It is a schematic cross-sectional view showing an example of arranging a covering member in the manufacturing method of the ceramic substrate according to the fourth embodiment. [Figure 13] It is a schematic cross-sectional view showing an example of contacting in the manufacturing method of the ceramic substrate according to the fourth embodiment. [Figure 14] It is a flowchart showing an example of preparing a ceramic plate in the manufacturing method of the ceramic substrate according to the fifth embodiment. [Figure 15] It is a schematic cross-sectional view showing an example of the ceramic substrate after peeling off the covering member in the manufacturing method of the ceramic substrate according to the fifth embodiment. [Figure 16] It is a schematic cross-sectional view showing an example of contacting after peeling off the covering member in the manufacturing method of the ceramic substrate according to the fifth embodiment. [Figure 17] It is a schematic cross-sectional view showing an example of peeling in the manufacturing method of the ceramic substrate according to the sixth embodiment. [Figure 18] It is a schematic cross-sectional view showing an example of the ceramic substrate after performing peeling in the manufacturing method of the ceramic substrate according to the sixth embodiment. [Figure 19A] It is a schematic cross-sectional view showing an example of the ceramic substrate according to the first embodiment. [Figure 19B] It is a schematic top view of the ceramic substrate of FIG. 19A. [Figure 19C] Figure 19A is a schematic bottom view of the ceramic substrate. [Figure 19D] Figure 19A is a schematic cross-sectional view along the XIXD-XIXD line. [Figure 20] This is a schematic cross-sectional view showing an example of a ceramic substrate according to the second embodiment. [Figure 21] This is a schematic cross-sectional view showing an example of a light-emitting device 200 according to the embodiment. [Figure 22A] This is a perspective view showing an application example of the light-emitting device according to the embodiment. [Figure 22B] Figure 22A is a cross-sectional view along the XXIIB-XXIIB line. [Figure 23] This is a flowchart showing an example of a method for manufacturing a light-emitting device according to an embodiment. [Figure 24A] The image shows a cross-sectional SEM view of the through-hole 2 after irradiation with laser light Z in S21-2, which is used to form the through-hole. [Figure 24B] The image shows a cross-sectional SEM view of the through-hole 2 after contact (S35). [Modes for carrying out the invention]

[0013] A ceramic substrate and a light-emitting device according to the embodiments of this disclosure, as well as a method for manufacturing them, will be described in detail with reference to the drawings. However, the embodiments described below are illustrative examples of ceramic substrates and light-emitting devices and methods for manufacturing them that embody the technical concept of this disclosure, and are not limited to those described below.

[0014] Furthermore, the dimensions, materials, shapes, and relative arrangements of the components described in the embodiments are merely illustrative examples and not intended to limit the scope of this disclosure unless otherwise specified. Note that the size and positional relationships of the components shown in each drawing may be exaggerated for clarity. Also, in the following description, the same name and reference numeral indicate the same or identical components, and detailed explanations are omitted as appropriate. To avoid overly complex drawings, schematic diagrams may be used with some elements omitted, or end views showing only the cross-section may be used as cross-sectional views.

[0015] Furthermore, in this disclosure, the term "polygon" refers to polygons such as rectangles, triangles, and quadrilaterals, including shapes where the corners of the polygon have been rounded, chamfered, or otherwise modified. Similarly, shapes where modifications have been made not only to the corners (ends of the sides) but also to the middle parts of the sides will also be referred to as polygons. In other words, shapes that retain the shape of a polygon but have been partially modified are included in the interpretation of "polygon" as described in this disclosure.

[0016] Furthermore, the same applies not only to polygons but also to terms describing specific shapes such as trapezoids, circles, and convex shapes. The same also applies when dealing with each side that forms such a shape. In other words, even if a side has been processed at a corner or in the middle, the interpretation of "side" includes the processed part. When distinguishing a "polygon" or "side" without partial processing from a processed shape, the term "strictly" should be added, for example, "strictly quadrilateral."

[0017] Furthermore, the following description uses terms to indicate specific directions or positions as needed (e.g., "up," "down," "side," "top surface," "bottom surface," "side," "X," "Y," "Z," and other terms including these terms). However, the use of these terms is solely to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not excessively limit the technical scope of the present invention. For example, if "top surface" is mentioned, the invention does not necessarily have to be used in a way that it always faces upwards. Also, in the embodiments, "covering" is not limited to direct contact, but also includes indirect covering, for example, through other components.

[0018] In each drawing, the Z-axis direction is defined as the thickness direction of the ceramic plate 1 or ceramic substrate 100, the direction approximately perpendicular to the Z-axis direction is defined as the X-axis direction, and the direction approximately perpendicular to both the Z-axis and X-axis directions is defined as the Y-axis direction. The X-axis, Y-axis, and Z-axis are mutually orthogonal.

[0019] Furthermore, in this specification or the claims, when there are multiple components and each is to be expressed separately, the components may be distinguished by adding "first," "second," etc., to their names.

[0020] [Method for manufacturing ceramic substrates] <First Embodiment> Figure 1 is a flowchart showing an example of a method for manufacturing a ceramic substrate according to the first embodiment. The method for manufacturing a ceramic substrate according to the first embodiment will be explained with reference to Figures 2A to 5D. Here, we show a method for manufacturing one ceramic substrate 100, but multiple ceramic substrates 100 may be manufactured simultaneously.

[0021] A method for manufacturing a ceramic substrate 100 according to the first embodiment includes: S1 preparing a ceramic plate 1 having a first surface 1a and a second surface 1b opposite to the first surface 1a, having a through hole 2 connecting the first surface 1a and the second surface 1b, wherein the maximum diameter N1 of the second opening 2b of the through hole formed on the second surface 1b is less than 0.90 times the maximum diameter M1 of the first opening 2a of the through hole 2 formed on the first surface 1a; S2 arranging a covering member so as to cover the first opening 2a of the through hole 2 formed on the first surface 1a; S3 bringing the inner surface defining the through hole 2 of the ceramic plate 1 on which the covering member 10 is arranged into contact with a first etching solution; and S4 peeling the covering member 10 from the first surface 1a. The method for manufacturing a ceramic substrate according to the first embodiment may further include, after peeling S4, placing a base metal 11 on the inner surface defining the through hole 2 of the ceramic plate 1 by sputtering, and then plating the base metal 11 by electroplating S15.

[0022] In the method for manufacturing a ceramic substrate according to the first embodiment, an embodiment in which the first etching solution contains an alkaline solution will be described. In this case, the first etching solution does not contain an acidic solution.

[0023] (S1) Prepare ceramic plate 1. Figure 2A is a schematic cross-sectional view showing an example of a ceramic plate used in the manufacturing method of a ceramic substrate according to the first embodiment. Figure 2B is a schematic top view of the ceramic plate in Figure 2A. Figure 2C is a schematic bottom view of the ceramic plate in Figure 2A. Note that Figure 2A is a schematic cross-sectional view taken along the line IIA-IIA in Figures 2B and 2C.

[0024] In preparing the ceramic plate 1 S1, the ceramic plate 1 is provided with a first surface 1a and a second surface 1b opposite to the first surface 1a, and has a through hole 2 connecting the first surface 1a and the second surface 1b, wherein the maximum diameter N1 of the second opening 2b of the through hole 2 formed on the second surface 1b is less than 0.90 times the maximum diameter M1 of the first opening 2a of the through hole 2 formed on the first surface 1a. That is, N1 / M1 < 0.90 is satisfied.

[0025] The ceramic plate 1 is an insulating material. The ceramic plate 1 may be a ceramic precursor in a softened state before sintering, or it may be a sintered ceramic, but it is preferable that it be a sintered ceramic because there is no dimensional change due to sintering, through holes 2 can be accurately formed at the desired position, and the size of the through holes 2 can be adjusted to a constant desired size.

[0026] There are no particular restrictions on the material of the ceramic plate 1, and it can be appropriately selected according to the purpose, but it is preferable that it contains aluminum nitride as the main material, and other auxiliary materials may also be included as needed. Here, "main material" means the material that makes up the largest amount of material in the materials constituting the ceramic plate 1.

[0027] There are no particular restrictions on the auxiliary materials used in the ceramic plate 1, but examples include ceramics other than aluminum nitride, glass, etc. These may be used individually or in combination of two or more types.

[0028] Other ceramics besides aluminum nitride are not particularly limited and include, for example, nitride-based ceramics such as silicon nitride and boron nitride; oxide-based ceramics such as aluminum oxide, silicon oxide, calcium oxide, and magnesium oxide; silicon carbide; mullite; and borosilicate glass. These may be used individually or in combination of two or more.

[0029] The ceramic plate 1 is preferably a plate-shaped member whose outer shape in plan view is rectangular. This rectangle may be a rectangle with a long side and a short side. Unless otherwise specified, a square may also be included in the definition of a rectangle. Furthermore, the outer shape of the ceramic plate 1 in plan view is not limited to a rectangle; it may also be a circle, an ellipse, a polygon, or the like.

[0030] The first surface 1a may or may not be flat, but it is preferable that it be flat when the ceramic substrate 100 is used in a light-emitting device, as this allows for a suitable arrangement of light-emitting elements.

[0031] The second surface 1b is the surface of the ceramic plate 1 opposite to the first surface 1a. The second surface 1b may be flat or not, but it is preferable that it be flat, as this allows for suitable placement on the mounting substrate when the ceramic substrate 100 is used in a light-emitting device.

[0032] In Figure 2A, the upper surface of the ceramic plate 1 is shown as the first surface 1a, and the lower surface of the ceramic plate 1 is shown as the second surface 1b. However, this is merely for convenience, and when the ceramic substrate 100 is used in a light-emitting device, the mounting substrate may be placed on the first surface 1a and the light-emitting element on the second surface 1b.

[0033] The first surface 1a and the second surface 1b are, for example, parallel. Here, when describing the surfaces of the ceramic plate 1 as "parallel," a difference of ±5 degrees is permitted.

[0034] The through-hole 2 connects the first surface 1a and the second surface 1b. The through-hole 2 is, for example, a via hole.

[0035] In a plan view of the ceramic plate 1, the shape of the first opening 2a of the through hole 2 formed on the first surface 1a and the shape of the second opening 2b of the through hole 2 formed on the second surface 1b are preferably circular or elliptical. However, the shapes of the first opening 2a and the second opening 2b of the through hole 2 in a plan view of the ceramic plate 1 are not limited to circular or elliptical, but may also be polygons including rectangles.

[0036] The maximum diameter M1 of the first opening 2a of the through hole 2 formed on the first surface 1a and the maximum diameter N1 of the second opening 2b of the through hole 2 formed on the second surface 1b in a plan view of the ceramic plate 1 are not particularly limited, as long as the maximum diameter N1 of the second opening 2b of the through hole formed on the second surface 1b is less than 0.90 times the maximum diameter M1 of the first opening 2a, and can be appropriately selected according to the purpose. For example, the maximum diameter M1 of the first opening 2a is preferably 110 μm or more and 150 μm or less, more preferably 125 μm or more and 135 μm or less, and the maximum diameter N1 of the second opening 2b is preferably 60 μm or more and 90 μm or less, more preferably 65 μm or more and 75 μm or less.

[0037] If the shapes of the first opening 2a and the second opening 2b of the through hole 2 are circular or elliptical, then "maximum diameter M1" and "maximum diameter N1" shall be "maximum diameter M1" and "maximum diameter N1," respectively. Furthermore, if the shapes of the first opening 2a and the second opening 2b of the through hole 2 in a plan view of the ceramic plate 1 are rectangular, then "maximum diameter M1" and "maximum diameter N1" shall be the maximum length of the diagonal between the first opening 2a and the second opening 2b, respectively.

[0038] There are no particular restrictions on the number of through holes 2 in the ceramic plate 1; there may be one or multiple holes, but from the viewpoint of mounting it in a light-emitting device, it is preferable to have multiple holes.

[0039] A commercially available ceramic plate 1 can be used, which comprises a first surface 1a and a second surface 1b opposite to the first surface 1a, and has a through hole 2 connecting the first surface 1a and the second surface 1b, wherein the maximum diameter N1 of the second opening 2b of the through hole formed in the second surface 1b is less than 0.90 times the maximum diameter M1 of the first opening 2a of the through hole 2 formed in the first surface 1a.

[0040] (S2) Arrange the covering member. Figure 3 is a schematic cross-sectional view showing an example of arranging a coating member in a method for manufacturing a ceramic substrate according to the first embodiment.

[0041] In step S2, the covering member 10 is positioned to cover the first opening 2a of the through hole 2 formed in the first surface 1a. In this case, the covering member 10 may be positioned to cover only the first opening 2a, or it may be positioned individually around the first opening 2a including the first opening 2a, or it may be positioned over the entire surface of the first surface 1a, but it is efficient to position the covering member 10 over the entire surface of the first surface 1a.

[0042] There are no particular restrictions on the material of the coating member 10, but resin materials or metal materials are examples. The resin material or metal material used for the coating member 10 is preferably a material that contains an alkaline solution and has resistance to the first etching solution or heat. These may be used individually or in combination of two or more.

[0043] Examples of resin materials for the covering member 10 include polyolefin, polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), and polystyrene (PS).

[0044] Examples of metal materials for the covering member 10 include cast steel such as FC200 and SCPH2, and stainless steel such as SUS.

[0045] In contacting the material (S3), if a first etching solution containing an alkaline solution is used, resin materials, cast steel, etc., can be suitably used.

[0046] The shape, structure, and size of the covering member 10 are not particularly limited as long as they can cover the first opening 2a of the through hole 2, and can be appropriately selected according to the purpose. Specific examples of the shape of the covering member 10 include tape, film, and plate shapes.

[0047] Among these, the covering member 10 is preferably at least one selected from tape, film, and metal plate.

[0048] (S3) Make contact Figure 4 is a schematic cross-sectional view showing an example of contact in the manufacturing method of a ceramic substrate according to the first embodiment.

[0049] In contact S3, the inner surface defining the through hole 2 of the ceramic plate 1 on which the covering member 10 is placed is brought into contact with the first etching solution. In the manufacturing method of the ceramic substrate according to the first embodiment, the first etching solution contains an alkaline solution.

[0050] As the first etching solution, it is preferable to use one in which the etching reaction rate with respect to aluminum nitride is faster than the etching reaction rate with respect to aluminum. Examples of alkaline solutions included in such a first etching solution include an alkaline solution containing one or more substances selected from the group consisting of potassium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, and magnesium hydroxide as a pH adjusting agent.

[0051] There are no particular limitations on the method of bringing the inner surface defining the through-holes 2 of the ceramic plate 1 on which the covering member 10 is placed into contact with the first etching solution containing an alkaline solution. A suitable method can be selected depending on the purpose. For example, one method is to immerse the ceramic plate 1 having the through-holes 2 in the first etching solution containing an alkaline solution, or to apply the first etching solution containing an alkaline solution from the first surface 1a side of the ceramic plate 1 so that it enters the through-holes 2 of the ceramic plate 1. Among these, the method of immersing the ceramic plate 1 having the through-holes 2 in the first etching solution containing an alkaline solution is efficient and preferred.

[0052] When the ceramic plate 1 is brought into contact with the first etching solution containing an alkaline solution while the covering member 10 is placed on the first surface 1a, the first etching solution containing the alkaline solution enters the interior of the through hole 2 from the second opening 2b side. Because the etching reaction rate of the first etching solution containing the alkaline solution to aluminum nitride is faster than the etching reaction rate to aluminum, the aluminum layer 3 inside the through hole 2 is difficult to etch, while the aluminum nitride, which is the main component of the ceramic plate, is easily etched. As a result, the ceramic plate 1 on the second opening 2b side of the through hole 2 is gradually etched. Along with this, the aluminum layer 3 is also removed from the second opening 2b side of the through hole 2 along with the etching of the aluminum nitride of the ceramic plate 1. On the other hand, the first opening 2a side of the through hole 2 is difficult to etch because the ceramic plate 1 is covered with the aluminum layer 3. As a result, during the etching reaction, the aluminum layer 3 is removed along with a portion of the ceramic plate 1 on the second opening 2b side of the through hole 2, and is therefore absent, while the aluminum layer 3 on the first opening 2a side of the through hole 2 remains. Due to this difference in the reactivity of the first etching solution containing the alkaline solution between the second opening 2b side and the first opening 2a side of the through hole 2, in the subsequent peeling process S4, the through hole 2 is formed in the ceramic substrate 100 obtained by peeling off the coating member 10 such that the maximum diameter N2 of the second opening 2b of the through hole 2 formed on the second surface 100b is 0.90 times or more and 1.10 times or less than the maximum diameter M2 of the first opening 2a of the through hole 2 formed on the first surface 100a.

[0053] The concentration of the pH adjusting agent contained in the first etching solution is not particularly limited as long as it can etch the inner surface defining the through-holes 2 of the ceramic plate 1, and can be appropriately selected according to the purpose. However, it is preferably 1.5 mol / L or more and 3.5 mol / L or less, and more preferably 2.5 mol / L or more and 3.5 mol / L or less. When the concentration of the pH adjusting agent contained in the first etching solution is 1.5 mol / L or more, the inner surface defining the through-holes 2 of the ceramic plate 1 can be etched efficiently. Furthermore, when the concentration of the pH adjusting agent contained in the first etching solution is 3.5 mol / L or less, the etching rate of the ceramic plate 1 does not become too fast, making it easier to adjust the opening diameter and shape of the through-holes 2 to the desired size.

[0054] In contact S3, the temperature at which the first etching solution containing the alkaline solution is brought into contact with the inner surface defining the through-holes 2 of the ceramic plate 1 is not particularly limited as long as the inner surface defining the through-holes 2 of the ceramic plate 1 can be etched, and can be appropriately selected according to the purpose, but 50°C or more and less than 100°C is preferred, and 70°C or more and 95°C or less is more preferred. If the temperature at which the first etching solution containing the alkaline solution is brought into contact with the inner surface defining the through-holes 2 of the ceramic plate 1 is 50°C or higher, the inner surface defining the through-holes 2 of the ceramic plate 1 can be etched efficiently. Also, if the temperature at which the first etching solution containing the alkaline solution is brought into contact with the inner surface defining the through-holes 2 of the ceramic plate 1 is less than 100°C, it is possible to prevent the first etching solution containing the alkaline solution from boiling.

[0055] In contact S3, the time for contacting the first etching solution containing the alkaline solution with the inner surface defining the through-hole 2 of the ceramic plate 1 is not particularly limited as long as the inner surface defining the through-hole 2 of the ceramic plate 1 can be etched, and can be appropriately selected according to the purpose, but 60 minutes or more and 180 minutes or less is preferred. If the contact time between the first etching solution containing the alkaline solution and the inner surface defining the through-hole 2 of the ceramic plate 1 is 60 minutes or more, the inner surface defining the through-hole 2 of the ceramic plate 1 can be etched efficiently. Furthermore, if the contact time between the first etching solution containing the alkaline solution and the inner surface defining the through-hole 2 of the ceramic plate 1 is 180 minutes or less, it is easier to adjust the opening diameter and shape of the through-hole 2 to the desired size, and it is possible to prevent the thickness of the ceramic plate 1 from being reduced by etching.

[0056] There are no particular restrictions on the atmospheric conditions for bringing the first etching solution containing an alkaline solution into contact with the inner surface defining the through-hole 2 of the ceramic plate 1 in contact S3, and it can be carried out under atmospheric pressure conditions.

[0057] Among these, in contact S3, it is preferable that the contact be carried out under atmospheric pressure conditions of less than 100°C for 60 minutes to 180 minutes, and more preferably under atmospheric pressure conditions of 70°C to less than 100°C for 60 minutes to 180 minutes.

[0058] (S4) Peel off Figure 5A is a schematic cross-sectional view showing an example of peeling in the manufacturing method of a ceramic substrate according to the first embodiment. Figure 5B is a schematic top view of the ceramic substrate of Figure 5A. Figure 5C is a schematic bottom view of the ceramic substrate of Figure 5A. Figure 5D is a schematic cross-sectional view of Figure 5A along the line VD-VD. Note that Figure 5A is a schematic cross-sectional view of Figures 5B, 5C, and 5D along the line VA-VA.

[0059] In peeling step S4, the coating member 10 is peeled off from the first surface 1a. This results in a ceramic substrate 100 having a first surface 100a and a second surface 100b on the opposite side of the first surface 100a, with a through hole 2 connecting the first surface 100a and the second surface 100b.

[0060] In peeling S4, the ceramic substrate 100 obtained by peeling off the coating member 10 has a maximum diameter N2 of the second opening 2b of the through hole 2 formed on the second surface 100b that is 0.90 times or more and 1.10 times or less than the maximum diameter M2 of the first opening 2a of the through hole 2 formed on the first surface 100a. That is, it satisfies 0.90 ≤ N2 / M2 ≤ 1.10. This is because, as described above, in contact S3, the etching reactivity of the first etching solution containing the alkaline solution with respect to the ceramic plate 1 and the aluminum layer 3 in the through hole 2 is different, so the etching of the inner surface of the through hole 2 on the second opening 2b side is accelerated compared to the etching of the inner surface of the through hole 2 on the first opening 2a side.

[0061] For similar reasons, in peeling S4, when the coating member 10 is peeled off, the ceramic substrate 100 obtained may have a maximum diameter P of the through-hole 2 in a cross section in a direction substantially perpendicular to the thickness direction of the ceramic substrate 100 at L / 2, where L is the average length between the first surface 100a and the second surface 100b in the thickness direction of the ceramic substrate 100, and the maximum diameter P of the through-hole 2 in the cross section in a direction substantially perpendicular to the thickness direction of the ceramic substrate 100 may be 0.90 times or more and 1.10 times or less than the maximum diameter M2 of the first opening 2a of the through-hole 2 in the first surface 100a.

[0062] The maximum diameter M2 of the first opening 2a of the through hole 2 formed in the first surface 100a of the ceramic substrate 100 in a plan view is at least 5 μm, and in some cases 10 μm or more, larger than the initial maximum diameter M1 of the first opening 2a due to etching or the like. The maximum diameter M2 of the first opening 2a of the through hole 2 is preferably 115 μm or more and 300 μm or less, and more preferably 150 μm or more and 180 μm or less.

[0063] The maximum diameter N2 of the second opening 2b of the through hole 2 formed in the second surface 100b of the ceramic substrate 100 in a plan view is larger than the initial maximum diameter N1 of the second opening 2b due to etching, etc., and is approximately the same size as the maximum diameter M2 of the first opening 2a. The maximum diameter N2 of the second opening 2b of the through hole 2 is preferably 105 μm or more and 330 μm or less, and more preferably 135 μm or more and 198 μm or less.

[0064] The maximum diameter P of the through-hole 2 in the cross-section of the ceramic substrate 100 in a direction substantially perpendicular to the thickness direction of the ceramic substrate 100 at L / 2 is larger than the initial opening diameter due to etching, etc., and is approximately the same size as the maximum diameter M2 of the first opening 2a and the maximum diameter N2 of the second opening 2b. The maximum diameter P of the through-hole 2 is preferably 105 μm or more and 330 μm or less, and more preferably 135 μm or more and 198 μm or less.

[0065] In the case of the ceramic substrate 100, there are no particular limitations on the method for peeling the coating member 10 from the first surface 1a of the ceramic plate 1, and an appropriate method can be selected depending on the material of the coating member 10. Examples include a chemical peeling method in which the coating member 10 is dissolved and peeled off with a solvent, a physical peeling method in which the coating member 10 is scraped off with a spatula, polished or ground, and a thermal peeling method in which the coating member 10 is thermally decomposed by heating.

[0066] In peeling S4, there are no particular restrictions on the arithmetic mean roughness Ra of the inner surface defining the through-hole 2, and it can be appropriately selected according to the purpose, but 5 μm or less is preferred. In contact S3, the inner surface defining the through-hole 2 of the ceramic plate 1 is brought into contact with the first etching solution containing an alkaline solution, thereby obtaining an inner surface defining the through-hole 2 with such an arithmetic mean roughness Ra. The arithmetic mean roughness Ra of the inner surface defining the through-hole 2 is measured in accordance with JIS B 0601 using a stylus-type surface roughness meter (for example, SE3500 manufactured by Kosaka Laboratory Co., Ltd.) equipped with a diamond stylus with a tip radius of curvature r of 2 μm.

[0067] The method for manufacturing a ceramic substrate according to the first embodiment allows for a constant distance between adjacent through holes, thereby increasing the design flexibility of the ceramic substrate.

[0068] <Second Embodiment> The method for manufacturing a ceramic substrate according to the second embodiment differs from the method for manufacturing a ceramic substrate according to the first embodiment in that, in contact S3, the first etching solution contains an acidic solution as a pH adjusting agent. In this case, the first etching solution does not contain an alkaline solution.

[0069] The changes to the placement of the covering member in S22, which are due to the change to making contact in S3, will also be explained below.

[0070] (S2) Arrange the covering member. There are no particular restrictions on the material of the covering member 10, but examples include resin materials or metal materials. These may be used individually or in combination of two or more types.

[0071] In contacting the material (S3), if a first etching solution containing an acidic solution is used, resin materials, stainless steel, etc., can be suitably used.

[0072] (S3) Make contact In contact S3, the inner surface defining the through-hole 2 of the ceramic plate 1 on which the covering member 10 is placed is brought into contact with the first etching solution. In the method for manufacturing a ceramic substrate according to the second embodiment, the first etching solution contains an acidic solution as a pH adjuster.

[0073] It is preferable to use a first etching solution in which the etching reaction rate for aluminum is faster than the etching reaction rate for aluminum nitride. Examples of acidic solutions included in such a first etching solution include one or more selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, citric acid, and acetic acid.

[0074] When the ceramic plate 1 is brought into contact with the first etching solution containing an acidic solution while the covering member 10 is placed on the first surface 1a, the first etching solution containing the acidic solution enters the interior of the through hole 2 from the second opening 2b side of the through hole 2. At this time, the first etching solution containing the acidic solution tends to remain on the first opening 2a side of the through hole 2, and the reaction between the first etching solution containing the acidic solution and the aluminum layer 3 proceeds, generating reactants within the through hole 2. On the other hand, on the second opening 2b side of the through hole 2, the first etching solution containing the acidic solution can easily enter and exit from outside the through hole 2, so even if the reaction between the first etching solution containing the acidic solution and the aluminum layer 3 proceeds, the concentration of reactants tends to be lower compared to the first opening 2a side of the through hole 2. Therefore, the inner surface of the through-hole 2 on the second opening 2b side is more easily contacted by the first etching solution containing a fresh acidic solution compared to the inner surface of the through-hole 2 on the first opening 2a side, and etching is promoted. As a result, the degree of etching differs between the inner surface of the through-hole 2 on the second opening 2b side and the inner surface of the through-hole 2 on the first opening 2a side. Consequently, in the subsequent peeling process S4, the through-hole 2 formed on the second surface 100b of the ceramic substrate 100 obtained by peeling off the coating member 10 is such that the maximum diameter N2 of the second opening 2b of the through-hole 2 formed on the first surface 100a is 0.90 times or more and 1.10 times or less than the maximum diameter M2 of the first opening 2a of the through-hole 2 formed on the first surface 100a.

[0075] The concentration of the pH adjusting agent contained in the first etching solution is not particularly limited as long as it can etch the inner surface defining the through-holes 2 of the ceramic plate 1, and can be appropriately selected according to the purpose, but it is preferably 8.0 mol / L or higher, and more preferably 10.0 mol / L or higher. When the concentration of the pH adjusting agent contained in the first etching solution is 8.0 mol / L or higher, the inner surface defining the through-holes 2 of the ceramic plate 1 can be etched efficiently.

[0076] When the first etching solution contains an acidic solution as a pH adjuster, the temperature at which the first etching solution and the inner surface defining the through-holes 2 of the ceramic plate 1 come into contact in contact S3 is not particularly limited as long as the inner surface defining the through-holes 2 of the ceramic plate 1 can be etched, and can be appropriately selected according to the purpose, but is preferably less than 100°C, and more preferably 20°C or more and 80°C or less. If the temperature at which the first etching solution containing the acidic solution and the inner surface defining the through-holes 2 of the ceramic plate 1 come into contact is less than 100°C, it is possible to prevent the first etching solution containing the acidic solution from boiling. Also, if the temperature at which the first etching solution containing the acidic solution and the inner surface defining the through-holes 2 of the ceramic plate 1 come into contact is 20°C or higher, the inner surface defining the through-holes 2 of the ceramic plate 1 can be etched efficiently.

[0077] In contact S3, the time for contacting the first etching solution containing the acidic solution with the inner surface defining the through-hole 2 of the ceramic plate 1 is not particularly limited as long as the inner surface defining the through-hole 2 of the ceramic plate 1 can be etched, and can be appropriately selected according to the purpose, but 60 minutes or more and 180 minutes or less is preferred, and 60 minutes or more and 120 minutes or less is more preferred. If the contact time between the first etching solution containing the acidic solution and the inner surface defining the through-hole 2 of the ceramic plate 1 is 60 minutes or more, the inner surface defining the through-hole 2 of the ceramic plate 1 can be etched efficiently. Furthermore, if the contact time between the first etching solution containing the acidic solution and the inner surface defining the through-hole 2 of the ceramic plate 1 is 180 minutes or less, it is easier to adjust the opening diameter and shape of the through-hole 2 to the desired size, and it is possible to prevent the thickness of the ceramic plate 1 from being reduced by etching.

[0078] <Third Embodiment> The method for manufacturing a ceramic substrate according to the third embodiment differs from the method for manufacturing a ceramic substrate according to the first embodiment or the method for manufacturing a ceramic substrate according to the second embodiment in that it includes further plating S15 after peeling S14.

[0079] Figure 6 is a flowchart showing an example of plating in the manufacturing method of a ceramic substrate according to the third embodiment.

[0080] (S15) Plating Figure 7 is a schematic cross-sectional view showing an example of arranging the base metal in the plating process in the manufacturing method of a ceramic substrate according to the third embodiment. Figure 8 is a schematic cross-sectional view showing an example of plating in the manufacturing method of a ceramic substrate according to the third embodiment.

[0081] In plating step S15, the base metal 11 is placed on the inner surface defining the through-holes 2 of the ceramic substrate 100 by sputtering, and then electroplated onto the base metal 11. This results in a ceramic substrate 100 in which the plated layer 12 is a conductor.

[0082] There are no particular restrictions on the material of the base metal 11, and it can be appropriately selected according to the purpose. Examples include Ti, W, TiW, Cu, Ni, NiCo, and NiSn. These may be used individually or in combination of two or more. Among these, Ti is preferred as the material of the base metal 11 in terms of adhesion to the substrate.

[0083] There are no particular restrictions on the average thickness of the base metal 11, and it can be appropriately selected depending on the purpose, but it is preferably 0.05 μm or more and 1.0 μm or less, and more preferably 0.3 μm or more and 0.7 μm or less. By setting the average thickness of the base layer made of the base metal 11 to 0.05 μm or more and 1.0 μm or less, stable adhesion strength can be expected. The average thickness of the base layer can be measured with a spectroscopic ellipsometer.

[0084] There are no particular restrictions on the material of the plating layer 12, and it can be appropriately selected according to the purpose. Examples include Au, Ag, Cu, Al, Sn, Pt, Zn, Ni, or alloys thereof. These may be used individually or in combination of two or more.

[0085] The method for manufacturing a ceramic substrate according to the third embodiment includes plating (S15), and therefore can produce a ceramic substrate 100 that can be suitably used in a light-emitting device.

[0086] <Fourth Embodiment> The method for manufacturing a ceramic substrate according to the fourth embodiment differs from the method for manufacturing a ceramic substrate according to the first embodiment or the second embodiment in that, in the step of preparing the ceramic plate 1 in S1, instead of using a commercially available ceramic plate 1, the method is changed to preparing a ceramic plate 1 that does not have through holes 2 by processing the through holes 2 in the following way, such that the maximum diameter N1 of the second opening 2b of the through hole formed on the second surface 1b is less than 0.90 times the maximum diameter M1 of the first opening 2a of the through hole 2 formed on the first surface 1a. Changes to the steps of arranging the covering member in S22, bringing it into contact in S23, and peeling it off in S24, which accompany the change in preparation in S21, will also be explained below.

[0087] The method for manufacturing a ceramic substrate according to the fourth embodiment may be modified by changing step S1 of preparing the ceramic plate 1 in the method for manufacturing a ceramic substrate according to the third embodiment to step S21.

[0088] Figure 9 is a flowchart showing an example of preparing a ceramic plate according to the manufacturing method of a ceramic substrate according to the fourth embodiment.

[0089] (S21) Preparations (S21-1) Prepare a ceramic plate that does not have through holes. Figure 10 is a schematic cross-sectional view showing an example of preparing a ceramic plate without through holes according to the manufacturing method of a ceramic substrate according to the fourth embodiment.

[0090] In preparing the ceramic plate S11, a ceramic plate 1 having a first surface 1a and a second surface 1b opposite to the first surface 1a is prepared. The ceramic plate 1 in preparing the ceramic plate S11 is the same as the ceramic plate 1 in the manufacturing method of the ceramic substrate according to the first embodiment or the manufacturing method of the ceramic substrate according to the second embodiment, except that it does not have through holes 2.

[0091] (S21-2) Forming through holes Figure 11A is a schematic cross-sectional view showing an example of forming through holes in a ceramic substrate manufacturing method according to the fourth embodiment. Figure 11B is a schematic top view of the ceramic plate shown in Figure 11A. Figure 11C is a schematic bottom view of the ceramic plate shown in Figure 11A. Note that Figure 11A is a schematic cross-sectional view taken along the line XIA-XIA in Figures 11B and 11C.

[0092] In forming through holes S21-2, through holes 2 are formed in the ceramic plate 1 such that the maximum diameter N1 of the second opening 2b of the through hole formed on the second surface 1b is less than 0.90 times the maximum diameter M1 of the first opening 2a of the through hole 2 formed on the first surface 1a.

[0093] In forming the through-hole in S21-2, there are no particular restrictions on the method for forming the through-hole 2 of the shape described above in the ceramic plate 1, and it can be appropriately selected according to the purpose. Examples include irradiating with laser light Z, drilling, and blasting. These may be used individually or in combination of two or more. Among these, the method of irradiating with laser light Z is preferred because it allows for the easy formation of small through-holes 2 even when using a sintered ceramic plate 1.

[0094] In forming a through hole S21-2, when using a method of irradiating with laser light Z, the laser light Z is irradiated from the first surface 1a to the second surface 1b to form a through hole 2 in the ceramic plate 1. Specifically, by irradiating a predetermined area of ​​the first surface 1a of the ceramic plate 1 with laser light Z in the Z-axis direction and performing thermal processing, the ceramics on the first surface 1a of the ceramic plate 1 are removed mainly by melting and sublimation in the irradiated area that absorbed the irradiated laser light Z. As a result, a through hole 2 connecting the first surface 1a to the second surface 1b is formed.

[0095] The through-hole 2 may be formed by a single irradiation of laser light Z, or it may be formed by gradually removing the ceramics by irradiating with laser light Z multiple times, but it is preferable to irradiate the same location with laser light Z only once.

[0096] The laser beam Z is not particularly limited as long as it can form through holes 2 such that the maximum diameter N1 of the second opening 2b of the through hole formed on the second surface 1b is less than 0.90 times the maximum diameter M1 of the first opening 2a of the through hole formed on the first surface 1a of the ceramic plate 1. However, a laser beam Z capable of thermal processing is preferred, and a laser beam having an oscillation wavelength of 750 nm or more or a laser beam having an output of 200 W or more is more preferred.

[0097] There are no particular restrictions on the pulse width of the laser beam Z, but it is preferable to include a continuous wave (CW). A continuous wave is defined as a laser beam Z with a pulse width that is maximized at the pulse repetition period.

[0098] Among these, the laser light Z preferably has a pulse width in the microsecond or nanosecond range, more preferably in the microsecond range, and even more preferably 1 microsecond or more and 23 microseconds or less.

[0099] Specific examples of laser light Z include Nd:YAG laser light, Nd:YVO4 laser light, fiber laser light, CO2 laser light, and disk laser light. These may be used individually or in combination of two or more types. Among these, CO2 laser light is preferred as the laser light Z.

[0100] There are no particular restrictions on the atmospheric conditions when irradiating with laser light Z; for example, a vacuum atmosphere or an inert gas atmosphere can be used. Examples of inert gases include N2 and CO2. These may be used individually or in combination of two or more.

[0101] There are no particular restrictions on the pulse width, output, and wavelength of the laser light Z. For example, processing can be performed using CO2 laser light (pulse: 10 microseconds x 1, wavelength: 10,096 nm, 2.5 kHz, 4 mJ). However, it is sufficient to form a through-hole 2 where the maximum diameter N1 of the second opening 2b of the through-hole 2 formed on the second surface 1b is less than 0.90 times the maximum diameter M1 of the first opening 2a of the through-hole 2 formed on the first surface 1a. The process is not limited to these conditions.

[0102] When a laser beam Z is irradiated onto the ceramic plate 1, irregularities are formed on the inner surface near the irradiated area of ​​the ceramic plate 1, that is, on the surface defining the through-hole 2, resulting in a roughened surface. The recesses on the inner surface defining the through-hole 2 have an irregular microstructure. In this disclosure, the irregular microstructure of the recesses on the inner surface defining the through-hole 2 may be referred to as, for example, dendritic or tree-like.

[0103] When using a ceramic plate 1 containing aluminum nitride as the main material, an aluminum layer 3 may precipitate continuously or fragmentarily on the inner surface defining the through-hole 2, i.e., the area irradiated by the laser beam Z on the ceramic plate 1. The aluminum layer 3 is formed in a state where it is embedded in the irregularities of the inner surface defining the through-hole 2. This is because, when the aluminum layer 3 is formed, the irradiation of the laser beam Z causes a rapid temperature rise in the aluminum nitride, resulting in a phase change in which a portion of the aluminum nitride melts and sublimes, causing ablation. In other words, the material constituting the ceramic plate 1 exists in the dendritic depressions on the lower surface of the aluminum layer 3. Thus, the lower surface of the aluminum layer 3 on the side where the ceramic plate 1 is placed contains both the material constituting the ceramic plate 1 and the precipitated aluminum.

[0104] (S22) Arrange the covering member. Figure 12 is a schematic cross-sectional view showing an example of arranging a coating member in a method for manufacturing a ceramic substrate according to the fourth embodiment.

[0105] In the fourth embodiment of the method for manufacturing a ceramic substrate, in the step of arranging the covering member S2, the covering member 10 is positioned to cover the first opening 2a of the through hole 2 formed in the first surface 1a. At this time, the aluminum layer 3 arranged on the inner surface of the through hole 2 is also covered by the covering member 10.

[0106] (S23) Make contact Figure 13 is a schematic cross-sectional view showing an example of contact in the manufacturing method of a ceramic substrate according to the fourth embodiment.

[0107] In the manufacturing method of the ceramic substrate according to the fourth embodiment, contact S23 is made by bringing the inner surface defining the through-hole 2 of the ceramic plate 1 on which the covering member 10 is placed into contact with the first etching solution. At this time, the first etching solution also comes into contact with the ceramic plate 1 on the second opening 2b side of the through-hole 2 and the aluminum layer 3 disposed on the inner surface of the through-hole 2. As a result, as described in the manufacturing method of the ceramic substrate according to the first embodiment or the manufacturing method of the ceramic substrate according to the second embodiment, the inner surface defining the through-hole 2 is etched, and the aluminum layer 3 is also removed by the first etching solution.

[0108] In the manufacturing method of the ceramic substrate according to the fourth embodiment, the use of laser light Z to process the through-hole 2 causes damage to the ceramic plate 1 at the boundary with the aluminum layer 3, resulting in a brittle state.

[0109] Therefore, when using a first etching solution containing an alkaline solution as the first etching solution, the ceramic plate 1 on the second opening 2b side of the through hole 2 is more easily etched and can be etched more efficiently compared to the method for manufacturing a ceramic substrate according to the first embodiment.

[0110] The method for manufacturing a ceramic substrate according to the fourth embodiment includes processing through holes 2 in the ceramic plate 1, and therefore, compared to the method for manufacturing a ceramic substrate according to the first embodiment or the method for manufacturing a ceramic substrate according to the second embodiment, it is possible to increase the design freedom of the ceramic substrate. In particular, when a laser beam Z is used to process the through holes 2, it is easy to make the through holes 2 small in diameter, to accurately form the through holes 2 at a desired position, and furthermore, the size of the through holes 2 can be adjusted to a certain desired size.

[0111] <Fifth Embodiment> The method for manufacturing a ceramic substrate according to the fifth embodiment differs from the method for manufacturing a ceramic substrate according to the first embodiment or the method for manufacturing a ceramic substrate according to the second embodiment in that, after peeling S4 as in the method for manufacturing a ceramic substrate according to the first embodiment or the method for manufacturing a ceramic substrate according to the second embodiment, it further includes bringing the area on the first surface 1a from which the coating member 10 has been peeled off into contact with the first etching solution or the second etching solution in S35.

[0112] The method for manufacturing a ceramic substrate according to the fifth embodiment may include peeling S4 or contacting S35 after peeling S24 in the method for manufacturing a ceramic substrate according to the third embodiment or the method for manufacturing a ceramic substrate according to the fourth embodiment.

[0113] Figure 14 is a flowchart illustrating an example of preparing a ceramic plate in the method for manufacturing a ceramic substrate according to the fifth embodiment. In the method for manufacturing a ceramic substrate according to the fifth embodiment, contact S23 corresponds to contact S3 in the method for manufacturing a ceramic substrate according to the first embodiment, the method for manufacturing a ceramic substrate according to the second embodiment, or the method for manufacturing a ceramic substrate according to the third embodiment, or contact S13 in the method for manufacturing a ceramic substrate according to the fourth embodiment, and contact S35 is an additional process in the method for manufacturing a ceramic substrate according to the fifth embodiment.

[0114] (S35) Make contact Figure 15 is a schematic cross-sectional view showing an example of a ceramic substrate after the coating member has been removed in the manufacturing method of the ceramic substrate according to the fifth embodiment. Figure 16 is a schematic cross-sectional view showing an example of contact after the coating member has been removed in the manufacturing method of the ceramic substrate according to the fifth embodiment.

[0115] In contacting S35, the area on the first surface 100a of the ceramic substrate 100 from which the coating member 10 was removed in peeling S34 is brought into contact with the first etching solution or the second etching solution.

[0116] In the peeling process S34, a portion of the coating member 10 may not be completely peeled off and may remain on the first surface 100a. For example, in the case of a tape with an adhesive layer, a portion of the adhesive layer may remain on the first surface 100a. The remaining portion of the coating member 10 will be referred to as the residue 10a. Furthermore, in the manufacturing method of the ceramic substrate according to the fifth embodiment, the aluminum layer 3 may remain on the inner surface defining the through hole 2, or as burrs on the first surface 100a and the second surface 100b. The remaining portion of the aluminum layer 3 will be referred to as the residue 3a. In the contact process S35, these residues 10a and 3a can be removed.

[0117] There are no particular restrictions on the method of bringing the residues 10a and 3a into contact with the first etching solution or the second etching solution, and a suitable method can be selected depending on the purpose. For example, methods include immersing the ceramic substrate 100 having the residues 10a and 3a in the first etching solution or the second etching solution, or applying the first etching solution or the second etching solution so as to come into contact with the residues 10a and 3a. Among these, the method of immersing the ceramic substrate 100 having the residues 10a and 3a in the first etching solution or the second etching solution is efficient and preferred.

[0118] In contact S35, a first etching solution with the same type and concentration of pH adjusting agent as in contact S23 may be used, or a second etching solution with a different type and / or concentration of pH adjusting agent than the first etching solution may be used. For example, in contact S23, a first etching solution containing an alkaline solution may be used, and in contact S35, a first etching solution containing an alkaline solution may also be used, or in contact S23, a first etching solution containing an alkaline solution may be used, and in contact S35, a second etching solution containing an acidic solution may be used.

[0119] The second etching solution is not particularly limited as long as it can remove the residual materials 10a and 3a, and can be appropriately selected according to the purpose. Examples include solutions containing alkaline or acidic solutions. The pH adjusting agent during the second etching is the same as the pH adjusting agent contained in the first etching solution.

[0120] The concentration of the pH adjusting agent contained in the second etching solution containing an alkaline solution is not particularly limited as long as it can remove residual substances 10a and 3a, and can be appropriately selected according to the purpose, but it is preferably 1.5 mol / L or more and 3.5 mol / L or less, and more preferably 2.5 mol / L or more and 3.5 mol / L or less.

[0121] The concentration of the pH adjusting agent contained in the second etching solution containing the acidic solution is not particularly limited as long as it can remove residual substances 10a and 3a, and can be appropriately selected according to the purpose, but it is preferably 8.0 mol / L or higher, and more preferably 10.0 mol / L or higher.

[0122] When the second etching solution contains an alkaline solution, the temperature at which the second etching solution is brought into contact with the residues 10a and 3a in contact S35 is not particularly limited as long as the residues 10a and 3a can be removed, and can be appropriately selected according to the purpose, but 50°C or more and less than 100°C is preferred, and 70°C or more and 95°C or less is more preferred.

[0123] When the second etching solution contains an acidic solution as a pH adjuster, the temperature at which the second etching solution is brought into contact with the residues 10a and 3a in contact S35 is not particularly limited as long as the residues 10a and 3a can be removed, and can be appropriately selected according to the purpose, but is preferably less than 100°C, and more preferably 20°C or more and 80°C or less.

[0124] In contacting the materials in step S35, there are no particular restrictions on the time for contacting the residues 10a and 3a with the first etching solution or the second etching solution, as long as the residues 10a and 3a can be removed. The contact time can be appropriately selected depending on the purpose, but a time of 5 minutes or more and 30 minutes or less is preferable. In contacting the materials in step S35, if the contact time between the residues 10a and 3a and the first etching solution or the second etching solution is 5 minutes or more, the residues 10a and 3a can be efficiently removed. Also, in contacting the materials in step S35, if the contact time between the residues 10a and 3a and the first etching solution or the second etching solution is 30 minutes or less, the ceramic plate 1 will not be over-etched, preventing a decrease in strength due to a reduction in the thickness of the ceramic plate 1, and the through-holes 2 will not be enlarged too much, suppressing adverse effects on the positional accuracy of the through-holes 2.

[0125] In contacting the residual materials 10a and 3a with the first or second etching solution in step S35, there are no particular restrictions on the atmospheric conditions, and it can be carried out under atmospheric pressure conditions.

[0126] Among these, the contact procedure S35, which is performed after peeling, is preferably carried out for 5 minutes to 30 minutes under atmospheric pressure conditions of less than 100°C, and more preferably carried out for 5 minutes to 30 minutes using a second etching solution containing an alkaline solution under atmospheric pressure conditions of 70°C to less than 100°C.

[0127] In the manufacturing method of the ceramic substrate according to the fifth embodiment, the residual material 10a and 3a on the first surface 100a of the ceramic substrate 100 can be removed by contacting it S35. Therefore, when the ceramic substrate 100 is used in a light-emitting device, the light-emitting element can be more suitably arranged on the first surface 100a.

[0128] <Sixth Embodiment> The method for manufacturing a ceramic substrate according to the sixth embodiment differs from the method for manufacturing a ceramic substrate according to the first embodiment or the method for manufacturing a ceramic substrate according to the second embodiment in that the peeling S4 in the method for manufacturing a ceramic substrate according to the first embodiment or the method for manufacturing a ceramic substrate according to the second embodiment is performed by polishing or grinding.

[0129] The method for manufacturing a ceramic substrate according to the sixth embodiment can also be applied to peeling steps S4, S14, S24, or S34 in the method for manufacturing a ceramic substrate according to the third embodiment, the method for manufacturing a ceramic substrate according to the fourth embodiment, or the method for manufacturing a ceramic substrate according to the fifth embodiment.

[0130] (Peeling off S4) Figure 17 is a schematic cross-sectional view showing an example of peeling in the manufacturing method of a ceramic substrate according to the sixth embodiment. Figure 18 is a schematic cross-sectional view showing an example of a ceramic substrate after peeling in the manufacturing method of a ceramic substrate according to the sixth embodiment.

[0131] In the method for manufacturing a ceramic substrate according to the sixth embodiment, the peeling S4 involves polishing or grinding the coating member 10 so that the first surface 1a is exposed. Polishing or grinding the coating member 10 may be done in combination with other methods for peeling the coating member 10, or it may be done alone.

[0132] By polishing or grinding the coating member 10, the coating member 10 can be peeled off, and even if there are residual materials 10a and 3a as described in the manufacturing method of the ceramic substrate according to the fifth embodiment, the residual materials 10a and 3a can be removed at the same time by polishing or grinding so that the first surface 1a is exposed.

[0133] In polishing or grinding so that the first surface 1a is exposed, not only the covering member 10 but also a part of the first surface 1a may be polished or ground. For example, the first surface 1a may be polished or ground with a QQ wire. This makes the first surface 100a of the ceramic substrate 100 smoother, and when the ceramic substrate 100 is used in a light-emitting device, the light-emitting elements can be arranged more favorably.

[0134] In the manufacturing method of the ceramic substrate according to the sixth embodiment, peeling S4 is performed by polishing or grinding, so when the ceramic substrate 100 is used in a light-emitting device, the light-emitting elements can be more suitably arranged on the first surface 100a of the ceramic substrate 100.

[0135] [Ceramic substrate] <First Embodiment> Figure 19A is a schematic cross-sectional view showing an example of a ceramic substrate according to the first embodiment. Figure 19B is a schematic top view of the ceramic substrate in Figure 19A. Figure 19C is a schematic bottom view of the ceramic substrate in Figure 19A. Figure 19D is a schematic cross-sectional view of Figure 19A along the line XIXD-XIXD. Note that Figure 19A is a schematic cross-sectional view of Figures 19B, 19C, and 19D along the line XIXA-XIXA.

[0136] The ceramic substrate 100 according to the first embodiment is a ceramic substrate 100 having a first surface 100a and a second surface 100b opposite to the first surface 100a, and having a through hole 2 connecting the first surface 100a and the second surface 100b, wherein the maximum diameter M2 of the first opening 2a of the through hole 2 on the first surface 100a is 80 μm or more and 300 μm or less, the maximum diameter N2 of the second opening 2b of the through hole 2 on the second surface 100b is 0.90 times or more and 1.10 times the maximum diameter M2 of the first opening 2a of the through hole 2 on the first surface 100a, and the arithmetic mean roughness Ra of the inner surface defining the through hole 2 is 5 μm or less. The ceramic substrate 100 according to the first embodiment may further have other configurations as needed. The ceramic substrate 100 according to the first embodiment can be used by appropriately referring to the configuration of the manufacturing method of the ceramic substrate 100 according to the first embodiment described above.

[0137] When there are multiple through holes 2, there are no particular restrictions on the arrangement of the multiple through holes 2 in a plan view of the ceramic substrate 100, or the pitch between one through hole 2 and other adjacent through holes 2, and these can be appropriately selected according to the purpose. However, since the maximum diameter N2 of the second opening 2b is less than 0.90 times the maximum diameter M2 of the first opening 2a, the pitch between a through hole 2 formed on the first surface 100a and other adjacent through holes 2 will be wider than the pitch between a through hole 2 formed on the second surface 100b and other adjacent through holes 2.

[0138] In the ceramic substrate 100 according to the first embodiment, the distance between adjacent through holes 2 can be kept constant, and the design of the ceramic substrate 100 offers a high degree of freedom.

[0139] <Second Embodiment> Figure 20 is a schematic cross-sectional view showing an example of a ceramic substrate according to the second embodiment.

[0140] The ceramic substrate 100 according to the first embodiment differs from the ceramic substrate 100 according to the first embodiment in that it further has a base metal 11 and a plating layer 12 on the base metal 11 on the inner surface defining the through hole 2.

[0141] There are no particular restrictions on the material of the base metal 11, and it can be appropriately selected according to the purpose. Examples include Ti, W, TiW, Cu, Ni, NiCo, and NiSn. These may be used individually or in combination of two or more. Among these, Ti is preferred as the material of the base metal 11 in terms of adhesion to the substrate.

[0142] There are no particular restrictions on the average thickness of the base metal 11, and it can be appropriately selected depending on the purpose, but it is preferably 0.05 μm or more and 1.0 μm or less, and more preferably 0.3 μm or more and 0.7 μm or less. By setting the average thickness of the base layer made of the base metal 11 to 0.05 μm or more and 1.0 μm or less, stable adhesion strength can be expected.

[0143] There are no particular restrictions on the material of the plating layer 12, and it can be appropriately selected according to the purpose. Examples include Au, Ag, Cu, Al, Sn, Pt, Zn, Ni, or alloys thereof. These may be used individually or in combination of two or more.

[0144] The ceramic substrate 100 according to the second embodiment has a plating layer 12 and can therefore be suitably used in a light-emitting device.

[0145] [Light-emitting device] Figure 21 is a schematic cross-sectional view showing an example of a light-emitting device 200 according to the embodiment. The various components of the light-emitting device 200 will be described below.

[0146] The light-emitting device 200 according to the embodiment includes a ceramic substrate 100 according to the embodiment, and a light-emitting element 202 having an electrode 205 disposed on the ceramic substrate 100.

[0147] The light-emitting device 200 is a device that emits light by arranging light-emitting elements 202 on a ceramic substrate 100. The number of light-emitting elements 202 may be one or multiple. Furthermore, if there are multiple light-emitting elements 202, there are no particular restrictions on their arrangement; for example, they may be arranged in a row.

[0148] The light-emitting device 200, as an example, includes a light-transmitting member 203 that covers the light extraction surface of the light-emitting element 202, a light-reflecting member 204 that covers the side surface of the light-emitting element 202 and the first surface 100a of the ceramic substrate 100, and a metal bump 206 that electrically connects the light-emitting element 202 and the plating layer 12 of the ceramic substrate 100.

[0149] While various wiring patterns can be formed on the ceramic substrate 100 depending on the application, in the light-emitting device 200 according to this embodiment, the light-emitting element 202 has a pair of electrodes 205 on the same side, and is face-down mounted with the side having the electrodes 205 facing the first surface 100a of the ceramic substrate 100.

[0150] In addition, the light-emitting device 200 according to this embodiment may be a face-up mounting in which the pair of electrodes 205 of the light-emitting element 202 are placed on the side opposite to the surface in contact with the ceramic substrate 100 and connected to the plating layer 12 of the ceramic substrate 100 by wire.

[0151] (Light-emitting element 202) The light-emitting element 202 includes a pair of electrodes 205, a semiconductor laminate 207, and an element substrate 208.

[0152] As an example, the light-emitting element 202 includes a semiconductor laminate 207 on the bottom side of the element substrate 208, and has a pair of electrodes 205 on the semiconductor laminate 207 side.

[0153] The semiconductor laminate 207 can be any composition depending on the desired emission wavelength, for example, a nitride semiconductor (In) capable of emitting blue or green light. x Al y Ga 1-x-y N, 0≦X, 0≦Y, X+Y≦1) or GaP, or GaAlAs or AlInGaP capable of emitting red light can be used. These may be used individually or in combination of two or more. The size and shape of the light-emitting element 202 can be appropriately selected depending on the purpose of use.

[0154] The element substrate 208 may, for example, be a sapphire substrate or a silicon substrate.

[0155] The electrode 205 is connected to the plating layer 12 of the ceramic substrate 100 via a bonding member 209 by a metal bump 206. One electrode 205 is a p electrode, and it is positioned at a distance that prevents electrical short circuits with the other n electrode. As an example, the electrode 205 is configured with one p electrode and one n electrode, but it may also be configured with two p electrodes and one n electrode on one side.

[0156] (Translucent member 203) The light-transmitting member 203 is positioned on the planar side of the element substrate 208, which is the light extraction surface. The light-transmitting member 203 is made of, for example, a light-transmitting resin material, and epoxy resin, silicone resin, or a resin mixture thereof can be used. The light-transmitting member 203 may contain a phosphor, for example, a phosphor that absorbs blue light from the light-emitting element 202 and emits yellow light, thereby enabling the emission of white light. Alternatively, the light-transmitting member 203 may contain multiple types of phosphors, for example, a phosphor that absorbs blue light from the semiconductor laminate 207 and emits green light, and a phosphor that emits red light, thereby enabling the emission of white light from the light-emitting element 202.

[0157] The phosphor to be contained in the light-transmitting member 203 is one that can be excited by light emitted from the light-emitting element 202. For example, one of the following specific examples can be used alone, or two or more can be used in combination. Specific examples of phosphors that can be excited by a blue light-emitting element or an ultraviolet light-emitting element include cerium-activated yttrium-aluminum-garnet phosphors (e.g., Y3(Al,Ga)5O 12 :Ce), cerium-activated lutetium-aluminum-garnet phosphors (e.g., Lu3(Al,Ga)5O 12:(Ce), nitrogen-containing calcium aluminosilicate-based phosphors activated with europium and / or chromium (e.g., CaO-Al2O3-SiO2:Eu), terbium-aluminum-garnet-based phosphors (e.g., Tb3(Al,Ga)5O 12 :(Ce), silicate-based phosphors activated with europium (e.g., (Sr,Ba)2SiO4:Eu), β-sialon-based phosphors (e.g., Si 6-z Al z O z N 8-z :Eu(0 < Z < 4.2)), α-sialon phosphors (e.g., Mz(Si,Al) 12 (O,N) 16 (where 0 < z ≤ 2 and M is Li, Mg, Ca, Y, and lanthanide elements excluding La and Ce)), nitride-based phosphors such as CASN-based phosphors (e.g., CaAlSiN3:Eu), SCASN-based phosphors (e.g., (Sr,Ca)AlSiN3:Eu), potassium fluorosilicate-based phosphors activated with manganese (e.g., K2SiF6:Mn, K2(Si,Al)F6:Mn, 3.5MgO·0.5MgF2·GeO2:Mn), sulfide-based phosphors, quantum dot phosphors (e.g., perovskite, chalcopyrite), etc. By combining these phosphors with a blue light-emitting element or an ultraviolet light-emitting element, various color light-emitting devices (e.g., white light-emitting devices) can be manufactured. When making a light-emitting device that can emit white light, it is adjusted to be white depending on the type and concentration of the phosphor contained in the translucent member 203. When such a phosphor is contained in the translucent member 203, the concentration of the phosphor is preferably about 5% or more and 50% or less.

[0158] (Metal bump 206) The metal bumps 206 are components that electrically connect the electrodes 205 and the plating layer 12. The metal bumps 206 may be positioned on either the electrode 205 side or the plating layer 12 side. The shape, size, and number of the metal bumps 206 can all be appropriately set as long as they can be positioned within the range of the electrodes 205. The size of the metal bumps 206 can be appropriately adjusted depending on the size of the semiconductor laminate 207, the required light emission output of the light-emitting element, etc. For example, a diameter of several tens of micrometers to several hundred micrometers is possible.

[0159] The metal bump 206 can be formed from, for example, Au, Ag, Cu, Al, Sn, Pt, Zn, Ni, or alloys thereof. The metal bump 206 can be formed from, for example, stud bumps known in the art. Stud bumps can be formed from stud bump bonders, wire bonding equipment, etc. Alternatively, the metal bump 206 may be formed from, for example, electroplating, electroless plating, vapor deposition, sputtering, or other methods known in the art.

[0160] As an example, the metal bumps 206 are joined here via a joining member 209. Examples of the joining member 209 used here include solders such as tin-bismuth, tin-copper, tin-silver, and gold-tin; eutectic alloys such as alloys mainly composed of Au and Sn, alloys mainly composed of Au and Si, and alloys mainly composed of Au and Ge; paste materials such as silver, gold, and palladium; anisotropic conductive materials such as ACP and ACF; brazing materials of low melting point metals; conductive adhesives and conductive composite adhesives that combine these materials.

[0161] (Light-reflecting member 204) The light-reflecting member 204 is a member that has light-reflecting properties. The light-reflecting member 204 is positioned to cover the first surface 100a of the ceramic substrate 100 and to cover the side surface of the light-emitting element 202. Furthermore, the light-reflecting member 204 is positioned to expose the light extraction surface of the light-emitting element 202 and is positioned to be coplanar with the light-reflecting member 204 of the light-emitting element 202. As an example, the light-reflecting member 204 is also positioned between the lower surface of the light-emitting element 202 and the first surface 100a of the ceramic substrate 100.

[0162] The light-reflecting member 204 preferably has a high reflectivity in order to effectively utilize the light from the light-emitting element 202. The light-reflecting member 204 is preferably white. The reflectivity of the light-reflecting member 204 is preferably 90% or more, and more preferably 94% or more, at the wavelength of light emitted by the light-emitting element 202.

[0163] The light-reflecting member 204 can be made of a thermoplastic resin such as acrylic resin, polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalate resin, polyethylene naphthalate resin, or polyester resin, or a thermosetting resin such as epoxy resin or silicone resin. As a light-diffusing material, known materials such as titanium dioxide, silicon dioxide, aluminum oxide, zinc oxide, or glass can be used.

[0164] The light-emitting device 200 uses one light-emitting element 202 as a unit for controlling brightness and on / off states, but the number of light-emitting elements 202 included in one unit may be one or multiple. For example, one unit can consist of four light-emitting elements 202 arranged in 1 row and 4 columns or 2 rows and 2 columns, or nine light-emitting elements 202 arranged in 3 rows and 3 columns, and the number of light-emitting elements 202 is not limited.

[0165] <Application examples of light-emitting devices> Figure 22A is a perspective view showing an application example of the light-emitting device according to the embodiment. Figure 22B is a cross-sectional view taken along the line XXIIB-XXIIB in Figure 22A. Note that Figure 22B omits some of the components of Figure 22A.

[0166] The light-emitting device 200 may be arranged in a row in a light-emitting module 300 (11 in Figure 22A), or 11 light-emitting devices 200 may be mounted on a single ceramic substrate 100. The configuration when it is a light-emitting module 300 will be described below.

[0167] The light-emitting module 300 comprises 11 light-emitting devices 200 in a row, with light-reflecting members 204 on the outer circumference of the light-emitting devices 200, a frame 301 on the outside of the light-reflecting members 204, and a module substrate 302 connected to the side of the ceramic substrate 100 opposite to the first surface 100a.

[0168] The frame 301 is a member that surrounds the light-reflecting members 204 that cover the multiple light-emitting devices 200. The frame 301 is formed in a rectangular ring shape, for example, which is rectangular in plan view, and is arranged to surround the light-reflecting members 204.

[0169] The frame 301 can be formed using a frame-shaped member made of metal, alloy, or ceramic. Examples of metals include Fe, Cu, Ni, Al, Ag, Au, Al, Pt, Ti, W, and Pd. Examples of alloys include alloys containing at least one selected from the group consisting of Fe, Cu, Ni, Al, Ag, Au, Al, Pt, Ti, W, and Pd.

[0170] Furthermore, a resin material may be used for the frame 301. In this case, the metal, alloy, or ceramic member may be embedded in the frame 301 formed of the resin material, or a part of the frame 301 may be made of resin material and the other part of it may be made of metal, alloy, or ceramic member.

[0171] The module substrate 302 is a component on which the light-emitting device 200 is mounted and electrically connects the light-emitting device 200 to the outside. The module substrate 302 is formed, for example, in a substantially rectangular shape in plan view. The module substrate 302 comprises a substrate portion 303 and a wiring board portion 304.

[0172] As the material for the substrate portion 303, it is preferable to use an insulating material, and also a material that does not easily transmit light emitted from the light-emitting element 202 or ambient light. For example, ceramics such as aluminum oxide, aluminum nitride, and mullite; thermoplastic resins such as polyamide, polyphthalamide, polyphenylene sulfide, and liquid crystal polymer; and resins such as epoxy resin, silicone resin, modified epoxy resin, urethane resin, and phenolic resin can be used. Among these, it is preferable to use ceramics, which have excellent heat dissipation properties, as the material for the substrate portion 303.

[0173] Furthermore, the wiring board portion 304 is formed on the substrate portion 303 at a position facing the plating layer 12 on the side of the ceramic substrate 100 of the light-emitting device 200 that is opposite to the first surface 100a. Examples of materials for the wiring board portion 304 include those exemplified as materials used for the plating layer 12.

[0174] The module substrate 302 is joined to the frame 301 via a conductive adhesive 305, and is arranged so that the plating layer 12 and the wiring board portion 304 are joined. For the conductive adhesive 305, for example, eutectic solder, conductive paste, or bumps may be used. In addition, in the light-emitting device 200, a protective element 306 is arranged on the ceramic substrate 100 in parallel with each light-emitting element 202.

[0175] As the light-emitting module 300 is configured as described above, when it is driven, the following occurs. Specifically, current is supplied from an external power source to the light-emitting element 202 via the wiring board portion 304, the plating layer 12, and the electrode 205, causing the light-emitting element 202 to emit light. The light emitted by the light-emitting element 202, if traveling upward, is taken out to the outside of the light-emitting device 200 via the light-transmitting member 203. Light traveling downward is reflected by the ceramic substrate 100 and taken out to the outside of the light-emitting device 200 via the light-transmitting member 203. Light traveling between the light-emitting element 202 and the frame 301 is reflected by the light-reflecting member 204 and the frame 301 and taken out to the outside of the light-emitting device 200 via the light-transmitting member 203. Light traveling between the light-emitting elements 202 is reflected by the light-reflecting member 204 and taken out to the outside of the light-emitting device 200 via the light-transmitting member 203. In this case, by narrowing the distance between the light-transmitting members 203 (for example, 0.2 mm or less), the optical system configuration can be made simpler and more compact, for example, when the light-emitting module 300 is used as a light source for a vehicle's headlight.

[0176] When manufacturing the light-emitting module 300, the light-emitting devices 200 are arranged on a sheet material, a frame 301 is placed around them, and the light-reflecting members 204 are placed in the space enclosed by the frame 301 and the sheet material. Then, the light-emitting devices 200, supported by the frame 301 and the light-reflecting members 204, are placed on a module substrate 302 on which the wiring board portion 304 and conductive adhesive 305 are arranged, and the light-emitting module 300 is manufactured by electrically connecting the plating layer 12 and the wiring board portion 304.

[0177] [Method for manufacturing a light-emitting device] A method for manufacturing a light-emitting device according to an embodiment includes preparing a ceramic substrate 100 manufactured by the method for manufacturing a ceramic substrate 100 according to an embodiment, and arranging a light-emitting element 202 equipped with an electrode 205 on the ceramic substrate 100. The electrode 205 and the plating layer 12 are electrically connected.

[0178] Figure 23 is a flowchart showing an example of a method for manufacturing a light-emitting device according to the embodiment. Note that, as an example, the method for manufacturing a light-emitting device according to the embodiment includes arranging a light-reflecting member.

[0179] (S41) Prepare a ceramic substrate. In preparing the ceramic substrate 100 in S41, the ceramic substrate 100 according to the embodiment is prepared.

[0180] Furthermore, the ceramic substrate 100 may have multiple areas for arranging the light-emitting elements 202, and after arranging the light-reflecting members 204, it may be sized to be a single piece for each light-emitting device 200, or it may be sized to be a single piece for each light-emitting device 200.

[0181] (S42): Arrange light-emitting elements. In S42, the placement of the light-emitting element, a light-emitting element 202 equipped with electrodes 205 is placed on the ceramic substrate 100. In S42, the electrodes 205 of the light-emitting element 202 are connected to a bonding member 209 placed on the plating layer 12 using metal bumps 206. The light-emitting element 202 is placed with a translucent member 203 already connected to the element substrate 208. When bonding the translucent member 203 to the element substrate 208, a translucent bonding material is used.

[0182] (S43) Arrange light-reflecting members. In step S43, the light-reflecting member 204 is positioned to cover the first surface 100a of the ceramic substrate 100 and the side surface of the light-emitting element 202. The light-reflecting member 204 is positioned on the ceramic substrate 100 so as to surround the light-emitting element 202 and expose the upper surface of the translucent member 203, which is the light extraction surface of the light-emitting element 202. The light-reflecting member 204 is positioned to form a rectangle in plan view.

[0183] In the manufacturing method of the light-emitting device according to the embodiment, after arranging the light-reflecting members in S43, individualization work is performed as needed. One unit of the light-emitting device 200 is predetermined by the number of light-emitting elements 202 used. Therefore, when multiple light-emitting devices 200 are manufactured together, individualization work is performed. When individualization work is performed, multiple light-emitting devices 200 are produced by cutting in a grid pattern. Examples of cutting methods include using a disc-shaped rotating blade, an ultrasonic cutter, a laser beam irradiation blade, etc. [Examples]

[0184] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way to these examples.

[0185] (Example 1) The ceramic substrate 100 was manufactured using the ceramic substrate manufacturing method by applying preparation step S21 in the flowchart shown in Figure 9 to preparation step S31 in the flowchart shown in Figure 14.

[0186] <(S21-1) Prepare a ceramic plate that does not have through holes.> In S21-1, a flat ceramic plate 1 with a thickness of 370 μm and no through holes, mainly composed of aluminum nitride, was prepared.

[0187] <(S21-2) Forming a through hole> Next, in forming the through hole S21-2, a CO2 laser beam Z (pulse: 10 microseconds x 1, wavelength: 10,096 nm, 2.5 kHz, 4 mJ) was irradiated from the first surface 1a of the ceramic plate 1 to form the through hole 2.

[0188] <(S32) Arrange the covering member> Next, in S32, when arranging the covering member, a tape made of polyolefin resin, which serves as the covering member 10, is placed over the entire surface of the first surface 1a, covering the first opening 2a of the through hole 2.

[0189] <(S33) Make contact> Next, in contact step S33, the ceramic plate 1 with the through-holes 2 formed was immersed in a 3.0 mol / L potassium hydroxide solution as the first etching solution and left at 80°C under atmospheric pressure for 90 minutes.

[0190] <(S34) Peel off> Next, in peeling step S34, the tape serving as the covering member 10 was peeled off to obtain the ceramic substrate 100.

[0191] <(S35) Make contact> Next, in contact step S35, the ceramic substrate 100 with the through-holes 2 formed was immersed in a 3.0 mol / L potassium hydroxide solution as the second etching solution and left at 80°C under atmospheric pressure for 20 minutes.

[0192] <<Observation of ceramic plate 1 and ceramic substrate 100>> The ceramic plate 1 after forming through holes (S21-2) and the ceramic substrate 100 after contacting them (S35) were each cut in the thickness direction by laser irradiation and observed with a scanning electron microscope (SEM) at a magnification of 250x.

[0193] Figure 24A shows a cross-sectional SEM image of the through-hole 2 after irradiation with laser light Z in the process of forming the through-hole S21-2. The scale bar is 200 μm. A precipitated aluminum layer 3 was observed on the inner surface defining the through-hole 2. The maximum diameter M1 of the first opening 2a was 130 μm, and the maximum diameter N1 of the second opening 2b was 70 μm. Therefore, the maximum diameter N1 of the second opening 2b (i.e., N1 / M1) was 0.54 times the maximum diameter M1 of the first opening 2a.

[0194] Figure 24B shows an SEM cross-sectional image of the through-hole 2 after contact S35. The scale bar is 200 μm. The precipitated aluminum layer 3 on the inner surface defining the through-hole 2 had been removed. Both the first opening 2a and the second opening 2b of the through-hole 2 had widened, but the second opening 2b was particularly widened. The maximum diameter M2 of the first opening 2a was 172 μm, and the maximum diameter N2 of the second opening 2b was 169 μm. Therefore, the maximum diameter N2 of the second opening 2b (i.e., N2 / M2) was 0.98 times that of the maximum diameter M2 of the first opening 2a.

[0195] As described above, the present invention has been explained based on specific embodiments, but these are merely examples, and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, additions, modifications, etc., are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0196] In addition to the embodiments described above, the following further notes are disclosed. (Note 1) To prepare a ceramic plate having a first surface and a second surface opposite to the first surface, having a through hole connecting the first surface and the second surface, wherein the maximum diameter of the second opening of the through hole formed on the second surface is less than 0.90 times the maximum diameter of the first opening of the through hole formed on the first surface, The covering member is positioned to cover the first opening of the through hole formed on the first surface, The inner surface defining the through-hole of the ceramic plate on which the covering member is placed is brought into contact with the first etching solution. The covering member is peeled off from the first surface, This is a method for manufacturing ceramic substrates, including [the specified element]. (Note 2) The method for manufacturing a ceramic substrate as described in Appendix 1, wherein, in the preparation described above, laser light is irradiated from the first surface toward the second surface to form the through hole in the ceramic plate. (Note 3) The method for manufacturing a ceramic substrate as described in Appendix 2, wherein the laser light used in the preparation is a laser light having an oscillation wavelength of 750 nm or more, or a laser light having an output of 200 W or more. (Note 4) The method for manufacturing a ceramic substrate according to any one of the appendices 1 to 3, wherein the covering member is at least one selected from tape, film, and metal plate. (Note 5) The method for producing a ceramic substrate according to any one of the appendices 1 to 4, wherein the first etching solution contains an alkaline solution containing one or more selected from the group consisting of potassium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, and magnesium hydroxide as a pH adjusting agent. (Note 6) The method for manufacturing a ceramic substrate as described in Appendix 5, wherein the concentration of the pH adjusting agent contained in the first etching solution is 1.5 mol / L or more and 3.5 mol / L or less. (Note 7) The method for producing a ceramic substrate according to any one of the appendices 1 to 6, wherein the first etching solution contains one or more acidic solutions selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, citric acid, and acetic acid as a pH adjusting agent. (Note 8) The method for manufacturing a ceramic substrate as described in Appendix 7, wherein the concentration of the pH adjusting agent contained in the first etching solution is 8.0 mol / L or higher. (Note 9) The method for manufacturing a ceramic substrate as described in any one of the appendices 1 to 8, wherein the contact is performed under atmospheric pressure conditions of less than 100°C for a period of 60 minutes or more and 180 minutes or less. (Note 10) The method for manufacturing a ceramic substrate according to any one of the appendices 1 to 9, further comprising bringing the area on the first surface from which the coating member was removed after the peeling into contact with the first etching solution or the second etching solution. (Note 11) The method for manufacturing a ceramic substrate as described in Appendix 10 involves bringing the substrate into contact with the surface after peeling, under atmospheric pressure conditions of less than 100°C for 5 minutes or more and 30 minutes or less. (Note 12) The method for manufacturing a ceramic substrate according to any one of the appendices 1 to 11, wherein the peeling includes polishing or grinding the coating member so that the first surface is exposed. (Note 13) The method for manufacturing a ceramic substrate according to any one of the appendices 1 to 12, wherein, in the peeling process, the maximum diameter of the second opening of the through hole formed on the second surface is 0.90 times or more and 1.10 times or less than the maximum diameter of the first opening of the through hole formed on the first surface. (Note 14) The method for manufacturing a ceramic substrate according to any one of the appendices 1 to 13, further comprising, after peeling, arranging a base metal on the inner surface defining the through hole of the ceramic plate by sputtering, and then plating the base metal by electroplating. (Note 15) In the preparation described above, the ceramic plate contains aluminum nitride, and the method for manufacturing a ceramic substrate is as described in any one of the appendices 1 to 14. (Note 16) In the preparation described above, the ceramic plate is a sintered ceramic plate, as described in any one of the appendices 1 to 15. (Note 17) The process involves preparing the ceramic substrate manufactured by the method for manufacturing the ceramic substrate described in any one of the appendices 1 to 16, The ceramic substrate is used to arrange light-emitting elements that have electrodes, This is a method for manufacturing a light-emitting device, including [the specified element]. (Note 18) A ceramic substrate having a first surface and a second surface opposite to the first surface, and having a through hole connecting the first surface and the second surface, The maximum diameter of the first opening of the through hole in the first surface is 80 μm or more and 300 μm or less. The maximum diameter of the second opening of the through hole on the second surface is 0.90 times or more and 1.10 times or less than the maximum diameter of the first opening of the through hole on the first surface. The ceramic substrate has an arithmetic mean roughness Ra of the inner surface defining the through-hole of 5 μm or less. (Note 19) The ceramic substrate as described in Appendix 18, wherein, when L is the average length between the first surface and the second surface in the thickness direction of the ceramic substrate, the maximum diameter of the through-hole in a cross-section in a direction substantially perpendicular to the thickness direction of the ceramic substrate at L / 2 is 0.90 times or more and 1.10 times or less than the maximum diameter of the first opening of the through-hole in the first surface. (Note 20) The ceramic substrate described in Appendix 18 or Appendix 19, A light-emitting element comprising electrodes is disposed on the ceramic substrate, It is a light-emitting device that has [a certain characteristic]. [Explanation of Symbols]

[0197] 1. Ceramic plate 1a 1st page 1b 2nd side 2 through holes 2a 1st opening 2b 2nd opening 3. Aluminum layer 3a Remnants 10 Covering member 10a Remnants 11. Base metal 12 Plating layer 100 ceramic substrates 200 Light-emitting devices 202 Light-emitting element 203 Translucent material 204 Light-reflecting member 205 Electrode 206 Metal Bump 207 Semiconductor Stack 208 element substrate 209 Joining member 300 Light-Emitting Modules 301 Frame 302 Module board 303 Circuit board section 304 Wiring board section 305 Conductive adhesive 306 Protective element

Claims

1. To prepare a ceramic plate having a first surface and a second surface opposite to the first surface, having a through hole connecting the first surface and the second surface, wherein the maximum diameter of the second opening of the through hole formed on the second surface is less than 0.90 times the maximum diameter of the first opening of the through hole formed on the first surface, The covering member is positioned to cover the first opening of the through hole formed on the first surface, The inner surface defining the through-hole of the ceramic plate on which the covering member is placed is brought into contact with the first etching solution. The covering member is peeled off from the first surface, A method for manufacturing ceramic substrates, including [the specified element].

2. The method for manufacturing a ceramic substrate according to claim 1, wherein, in the preparation described above, laser light is irradiated from the first surface toward the second surface to form the through hole in the ceramic plate.

3. The method for manufacturing a ceramic substrate according to claim 2, wherein, in the preparation described above, the laser light is a laser light having an oscillation wavelength of 750 nm or more or a laser light having an output of 200 W or more.

4. The method for manufacturing a ceramic substrate according to claim 1, wherein the covering member is at least one selected from tape, film, and metal plate.

5. The method for producing a ceramic substrate according to claim 1, wherein the first etching solution contains an alkaline solution containing one or more selected from the group consisting of potassium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, and magnesium hydroxide as a pH adjusting agent.

6. The method for manufacturing a ceramic substrate according to claim 5, wherein the concentration of the pH adjusting agent contained in the first etching solution is 1.5 mol / L or more and 3.5 mol / L or less.

7. The method for producing a ceramic substrate according to claim 1, wherein the first etching solution contains one or more acidic solutions selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, citric acid, and acetic acid as a pH adjusting agent.

8. The method for manufacturing a ceramic substrate according to claim 7, wherein the concentration of the pH adjusting agent contained in the first etching solution is 8.0 mol / L or more.

9. The method for manufacturing a ceramic substrate according to claim 1, wherein the contact is performed under atmospheric pressure conditions of less than 100°C for 60 minutes or more and 180 minutes or less.

10. The method for manufacturing a ceramic substrate according to claim 1, further comprising bringing the region on the first surface from which the coating member was removed after the peeling, into contact with the first etching solution or the second etching solution.

11. The method for manufacturing a ceramic substrate according to claim 10, wherein the contacting after peeling is performed under atmospheric pressure conditions of less than 100°C for 5 minutes or more and 30 minutes or less.

12. The method for manufacturing a ceramic substrate according to claim 1, wherein the peeling includes polishing or grinding the coating member so that the first surface is exposed.

13. The method for manufacturing a ceramic substrate according to claim 1, wherein, in the peeling process, the maximum diameter of the second opening of the through hole formed on the second surface is 0.90 times or more and 1.10 times or less than the maximum diameter of the first opening of the through hole formed on the first surface.

14. The method for manufacturing a ceramic substrate according to claim 1, further comprising, after peeling, arranging a base metal on the inner surface defining the through hole of the ceramic plate by sputtering, and then plating the base metal by electroplating.

15. The method for manufacturing a ceramic substrate according to claim 1, wherein the ceramic plate contains aluminum nitride in the preparation described above.

16. The method for manufacturing a ceramic substrate according to claim 1, wherein the ceramic plate is a sintered ceramic plate in the preparation described above.

17. The process involves preparing the ceramic substrate manufactured by the method for manufacturing the ceramic substrate described in any one of claims 1 to 16, The ceramic substrate is used to arrange light-emitting elements that have electrodes, A method for manufacturing a light-emitting device, including the method described above.

18. A ceramic substrate having a first surface and a second surface opposite to the first surface, and having a through hole connecting the first surface and the second surface, The maximum diameter of the first opening of the through hole in the first surface is 80 μm or more and 300 μm or less. The maximum diameter of the second opening of the through hole on the second surface is 0.90 times or more and 1.10 times or less than the maximum diameter of the first opening of the through hole on the first surface. A ceramic substrate having an arithmetic mean roughness Ra of the inner surface defining the through-hole of 5 μm or less.

19. The ceramic substrate according to claim 18, wherein, when L is the average length between the first surface and the second surface in the thickness direction of the ceramic substrate, the maximum diameter of the through hole in a cross section in a direction substantially perpendicular to the thickness direction of the ceramic substrate at L / 2 is 0.90 times or more and 1.10 times or less than the maximum diameter of the first opening of the through hole in the first surface.

20. The ceramic substrate according to claim 18 or claim 19, A light-emitting element comprising electrodes is disposed on the ceramic substrate, A light-emitting device having the following features.

Images