Ceramic substrate, light emitting device, and manufacturing method of the same

Abstract

To provide a ceramic substrate and a light emitting device capable of suppressing corrosion of a Cu layer in the ceramic substrate having the Cu layer and having excellent reliability, and provide a manufacturing method of them.SOLUTION: A ceramic substrate 100 includes: a ceramic plate 1; a seed layer 2 disposed on an upper surface of the ceramic plate 1; a Cu layer 3 disposed on the upper surface of the seed layer 2; one or two or more layers of an intermediate layer 4 disposed on the upper surface of the Cu layer 3 and a side surface of the Cu layer 3; and an Au layer 5 disposed on an upper surface of the intermediate layer 4 and a side surface of the intermediate layer 4. The upper surface of the seed layer 2 and the intermediate layer 4 are in contact with each other, the upper surface of the ceramic plate 1 and the Au layer 5 are not in contact with each other. An edge part 2a of the upper surface of the seed layer 2 is outside an edge part 3b of a lower surface of the Cu layer 3 in a horizontal direction.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to a ceramic substrate, a light emitting device, and methods for manufacturing the same. [Background technology]

[0002] In recent years, miniaturization of microchips (semiconductor integrated circuits) has been required to reduce the size, functionality, and integration of electronic devices or components. Photolithography techniques, for example, are used to make the wiring inside semiconductors finer (see, for example, Patent Document 1).

[0003] One method for forming wiring using photolithography is to form a wiring of a desired shape by depositing a metal film on a substrate and then removing unnecessary portions of the metal film by etching. However, this method has the risk of damaging the substrate or changing the composition of the conductive film during etching, and it is described that a lift-off method may be used to form wiring (see, for example, Patent Document 2).

[0004] On the other hand, copper (Cu) is used for wiring because of its high conductivity. However, copper is susceptible to corrosion even under normal environments due to moisture in the air, etc. Therefore, a method is known in which a plating layer such as nickel (Ni), rhodium (Rh), or gold (Au) is formed on the copper surface (see Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-108213 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-347706 [Patent Document 3] Patent No. 4706690 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a ceramic substrate having a Cu layer, which can suppress corrosion of the Cu layer and has excellent reliability, a light emitting device, and methods for manufacturing the same. [Means for solving the problem]

[0007] A ceramic substrate according to one embodiment of the present disclosure comprises a ceramic plate, a seed layer disposed on the upper surface of the ceramic plate, a Cu layer disposed on the upper surface of the seed layer, one or more intermediate layers disposed on the upper surface and sides of the Cu layer, and an Au layer disposed on the upper surface and sides of the intermediate layer, wherein the upper surface of the seed layer is in contact with the lower surface of the intermediate layer, the upper surface of the ceramic plate is not in contact with the lower surface of the Au layer, and in the horizontal direction, the edge of the upper surface of the seed layer is outside the edge of the lower surface of the Cu layer.

[0008] A light emitting device according to an embodiment of the present disclosure includes a ceramic substrate according to an embodiment of the present disclosure and a light emitting element disposed on the ceramic substrate.

[0009] A method for manufacturing a ceramic substrate according to one embodiment of the present disclosure includes: providing a first resist layer on the upper surface of a ceramic plate; exposing and developing the first resist layer to a predetermined shape; arranging a seed layer on the upper surface of the ceramic plate exposed from the first resist layer after exposure and development, on the side surface of the first resist layer, and on the upper surface of the first resist layer; providing a second resist layer to cover at least a portion of the upper surface of the seed layer; exposing and developing the second resist layer to a predetermined shape so that at least a portion of the upper surface of the seed layer disposed on the upper surface of the ceramic plate is exposed; arranging a Cu layer by electroplating on the upper surface of the seed layer exposed from the second resist layer after exposure and development; removing a portion of the seed layer, the first resist layer, and the second resist layer;

[0010] A method for manufacturing a ceramic substrate according to one embodiment of the present disclosure includes preparing a ceramic substrate according to one embodiment of the present disclosure, arranging a light-emitting element on the ceramic substrate, and arranging a reflective member on an upper surface of the ceramic substrate, wherein the reflective member is arranged so as to contact the Au layer and the seed layer of the ceramic substrate. [Effects of the Invention]

[0011] According to an embodiment of the present disclosure, it is possible to provide a ceramic substrate having a Cu layer, in which corrosion of the Cu layer can be suppressed, and a highly reliable ceramic substrate, a light emitting device, and methods for manufacturing the same. [Brief explanation of the drawings]

[0012] [Figure 1A] 1 is a schematic cross-sectional view showing an example of a ceramic substrate according to a first embodiment. [Figure 1B] 1 is a schematic top view illustrating an example of a ceramic substrate according to a first embodiment. [Figure 2] FIG. 10 is a schematic cross-sectional view showing an example of a ceramic substrate according to a second embodiment. [Figure 3] FIG. 10 is a schematic cross-sectional view showing an example of a ceramic substrate according to a third embodiment. [Figure 4A] FIG. 10 is a schematic top view showing an example of a ceramic substrate according to a fourth embodiment. [Figure 4B] 4B is a schematic cross-sectional view in the lamination direction taken along line IVB-IVB in FIG. 4A. [Figure 4C] FIG. 4C is an enlarged cross-sectional view of a region IVC of the ceramic substrate according to the embodiment 4-1 of FIG. 4B. [Figure 4D] FIG. 4C is an enlarged cross-sectional view of a region IVC of the ceramic substrate according to the embodiment 4-2 of FIG. 4B. [Figure 4E] FIG. 10 is a schematic bottom view showing an example of a ceramic substrate according to a fourth embodiment. [Figure 5] 3 is a flowchart showing an example of a method for manufacturing a ceramic substrate according to the first embodiment. [Figure 6A] 1 is a schematic cross-sectional view showing an example of a ceramic plate used in a method for manufacturing a ceramic substrate according to a first embodiment. [Figure 6B] 3 is a schematic cross-sectional view showing an example of providing a first resist layer on the upper surface of the ceramic substrate in the method for manufacturing the ceramic substrate according to the first embodiment. FIG. [Figure 6C] 3 is a schematic cross-sectional view showing an example of exposing and developing a first resist layer into a predetermined shape in the method for manufacturing a ceramic substrate according to the first embodiment. FIG. [Figure 6D] 3 is a schematic cross-sectional view showing an example of arranging a seed layer in the method for manufacturing a ceramic substrate according to the first embodiment. FIG. [Figure 6E] 5 is a schematic cross-sectional view showing an example of providing a second resist layer on the upper surface of the ceramic substrate so as to cover the seed layer in the method for manufacturing the ceramic substrate according to the first embodiment. FIG. [Figure 6F] 4 is a schematic cross-sectional view showing an example of exposing and developing the second resist layer into a predetermined shape in the method for manufacturing the ceramic substrate according to the first embodiment. FIG. [Figure 6G] FIG. 3 is a schematic cross-sectional view showing an example of arranging a Cu layer in the method for manufacturing a ceramic substrate according to the first embodiment. [Figure 6H] 3A and 3B are schematic cross-sectional views showing an example of removing a part of a seed layer, a first resist layer, and a second resist layer in the method for manufacturing a ceramic substrate according to the first embodiment. [Figure 6I] 3 is a schematic cross-sectional view showing an example of arranging an intermediate layer in the method for manufacturing a ceramic substrate according to the first embodiment. FIG. [Figure 6J] FIG. 3 is a schematic cross-sectional view showing an example of arranging an Au layer in the method for manufacturing a ceramic substrate according to the first embodiment. [Figure 7] 10 is a flowchart showing an example of a method for manufacturing a ceramic substrate according to a second embodiment. [Figure 8A] FIG. 10 is a schematic cross-sectional view showing an example of arranging a first intermediate layer in the method for manufacturing a ceramic substrate according to the second embodiment. [Figure 8B] FIG. 10 is a schematic cross-sectional view showing an example of arranging a second intermediate layer in the method for manufacturing a ceramic substrate according to the second embodiment. [Figure 8C] FIG. 10 is a schematic cross-sectional view showing an example of arranging an Au layer in the method for manufacturing a ceramic substrate according to the second embodiment. [Figure 9] 10 is a flowchart showing an example of a method for manufacturing a ceramic substrate according to a third embodiment. [Figure 10A] FIG. 10 is a schematic cross-sectional view showing an example of exposing and developing a first resist layer into a predetermined shape in the method for manufacturing a ceramic substrate according to the third embodiment. [Figure 10B] FIG. 10B is an enlarged cross-sectional view of region XB in FIG. 10A. [Figure 10C] FIG. 10 is a schematic cross-sectional view showing an example of arranging a seed layer in the method for manufacturing a ceramic substrate according to the third embodiment. [Figure 10D] FIG. 10 is a schematic cross-sectional view showing an example of providing a second resist layer in the method for manufacturing a ceramic substrate according to the third embodiment. [Figure 10E] 10 is a schematic cross-sectional view showing an example of exposing and developing the second resist layer into a predetermined shape in the method for manufacturing a ceramic substrate according to the third embodiment. FIG. [Figure 10F] FIG. 10 is a schematic cross-sectional view showing an example of arranging a Cu layer in the method for manufacturing a ceramic substrate according to the third embodiment. [Figure 10G] 10 is a schematic cross-sectional view showing an example of removing a part of the seed layer, the first resist layer, and the second resist layer in the method for manufacturing a ceramic substrate according to the third embodiment. FIG. [Figure 10H] FIG. 10 is a schematic cross-sectional view showing an example of arranging an intermediate layer in the method for manufacturing a ceramic substrate according to the third embodiment. [Figure 10I] FIG. 10 is a schematic cross-sectional view showing an example of arranging an Au layer in the method for manufacturing a ceramic substrate according to the third embodiment. [Figure 11] 10 is a flowchart showing an example of a method for manufacturing a ceramic substrate according to a fourth embodiment. [Figure 12A] FIG. 10 is a schematic cross-sectional view showing an example of exposing and developing a first resist layer into a predetermined shape in the method for manufacturing a ceramic substrate according to a fourth embodiment. [Figure 12B] FIG. 12B is an enlarged cross-sectional view of region XIIB of FIG. 12A. [Figure 12C] FIG. 10 is a schematic cross-sectional view showing an example of arranging a seed layer in the method for manufacturing a ceramic substrate according to the fourth embodiment. [Figure 12D] FIG. 10 is a schematic cross-sectional view showing an example of providing a second resist layer in the method for manufacturing a ceramic substrate according to the fourth embodiment. [Figure 12E] FIG. 10 is a schematic cross-sectional view showing an example of exposing and developing the second resist layer into a predetermined shape in the method for manufacturing a ceramic substrate according to the fourth embodiment. [Figure 12F] FIG. 10 is a schematic cross-sectional view showing an example of arranging a Cu layer in the method for manufacturing a ceramic substrate according to the fourth embodiment. [Figure 12G]10 is a schematic cross-sectional view showing an example of removing a part of a seed layer, a first resist layer, and a second resist layer in a method for manufacturing a ceramic substrate according to a fourth embodiment. FIG. [Figure 12H] FIG. 10 is a schematic cross-sectional view showing an example of arranging an intermediate layer in the method for manufacturing a ceramic substrate according to the fourth embodiment. [Figure 12I] FIG. 10 is a schematic cross-sectional view showing an example of arranging an Au layer in the method for manufacturing a ceramic substrate according to the fourth embodiment. [Figure 13A] 1 is a schematic top view illustrating an example of a light emitting device according to an embodiment. [Figure 13B] 13B is a schematic cross-sectional view taken along line XIIIB-XIIIB in FIG. 13A in the stacking direction. [Figure 13C] FIG. 13C is an enlarged cross-sectional view of region XIIIC of FIG. 13B. [Figure 13D] FIG. 13D is an enlarged cross-sectional view of region XIIID of FIG. 13C. [Figure 14] 1 is a flowchart illustrating an example of a method for manufacturing a light emitting device according to an embodiment. [Figure 15A] 10 is an SEM image of a plan view in the horizontal direction of an intermediate ceramic substrate obtained by disposing a Cu layer in a method for manufacturing a ceramic substrate according to a fourth embodiment, observed from above at 50x magnification. [Figure 15B] 15B is an enlarged image of a cross section in the thickness direction of region XVB in FIG. 15A, and is an SEM image observed at 10,000 times of a cross section of an intermediate ceramic substrate obtained by disposing a Cu layer in the manufacturing method of a ceramic substrate according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] A ceramic substrate and a light-emitting device according to an embodiment of the present disclosure, as well as a method for manufacturing the same, will be described in detail with reference to the drawings. However, the embodiments shown below are merely examples of a ceramic substrate and a light-emitting device, as well as a method for manufacturing the same, that embody the technical concept of the present disclosure, and are not limited to the following.

[0014] Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, etc. of components described in the embodiments are not intended to limit the scope of the present disclosure, and are merely illustrative examples. The sizes, positional relationships, etc. of components shown in each drawing may be exaggerated for clarity. In the following description, the same names and symbols indicate the same or similar components, and detailed descriptions will be omitted as appropriate. To avoid overly complex drawings, schematic diagrams may be used in which some elements are omitted, or end views showing only the cut surface may be used as cross-sectional views.

[0015] Furthermore, in this disclosure, polygons such as rectangles, triangles, and quadrilaterals are referred to as polygons, including shapes in which the corners of the polygons have been processed, such as by rounding, chamfering, corner removal, or rounding. Shapes in which processing has been applied not only to the corners (edges of the edges) but also to the middle portions of the edges are also referred to as polygons. In other words, shapes in which partial processing has been applied while retaining the polygon as a base are included in the interpretation of "polygon" described in this disclosure.

[0016] The same applies not only to polygons, but also to words that represent specific shapes such as trapezoids, circles, and irregularities. The same also applies when dealing with the sides that form the shape. In other words, even if the corners or middle part of a side have been processed, the interpretation of "side" includes the processed part. Note that when distinguishing a "polygon" or "side" that has no processing from a processed shape, the word "strict" is added, for example, "strict quadrangle."

[0017] Furthermore, in the following description, terms indicating specific directions or positions (e.g., "upper," "lower," "side," "upper surface," "lower surface," "side," "X," "Y," "Z," and other terms including these terms) are used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not unduly limit the technical scope of the present invention. For example, when describing an "upper surface," it does not necessarily mean that the invention must always be used facing upward. Furthermore, in the embodiments, "covering" does not necessarily mean direct contact, but also includes indirect covering, for example, via another member.

[0018] Furthermore, in this specification or claims, when there are multiple elements of a certain type and each element needs to be expressed separately, the elements may be distinguished by adding "first," "second," etc. to the beginning of the element.

[0019] [Ceramic substrate] First Embodiment Fig. 1A is a schematic cross-sectional view showing an example of a ceramic substrate according to Embodiment 1. Fig. 1B is a schematic top view showing an example of a ceramic substrate according to Embodiment 1. Each component of the ceramic substrate 100 will be described below.

[0020] The ceramic substrate 100 according to the first embodiment includes a ceramic plate 1, a seed layer 2 disposed on the upper surface of the ceramic plate 1, a Cu layer 3 disposed on the upper surface of the seed layer 2, one intermediate layer 4 disposed on the upper surface of the Cu layer 3 and on the side surfaces of the Cu layer 3, and an Au layer 5 disposed on the upper surface of the intermediate layer 4 and on the side surfaces of the intermediate layer 4, wherein the upper surface of the seed layer 2 and the lower surface of the intermediate layer 4 are in contact, the upper surface of the ceramic plate 1 and the lower surface of the Au layer 5 are not in contact, and an edge 2a of the upper surface of the seed layer 2 is located outside an edge 3b of the lower surface of the Cu layer 3 in the horizontal direction. The ceramic substrate 100 according to the first embodiment may further include other configurations as necessary.

[0021] The stacking direction in which the ceramic plate 1, the seed layer 2, the Cu layer 3, the intermediate layer 4, and the Au layer 5 are stacked is the Z-axis direction. The axis perpendicular to the Z-axis direction, which is the stacking direction, is the X-axis. The axis perpendicular to the Z-axis direction, which is the stacking direction, and perpendicular to the X-axis direction is the Y-axis. The X-axis, Y-axis, and Z-axis are mutually orthogonal. The horizontal direction of the ceramic plate 1 may be the X-axis direction or the Y-axis direction as long as it is perpendicular to the Z-axis direction, which is the stacking direction. In this specification, the XY plane is defined as the horizontal plane of the ceramic substrate 100, and both the X-axis direction and the Y-axis direction are defined as the horizontal direction of the ceramic substrate 100.

[0022] In the ceramic substrate 100, a region where the seed layer 2, the Cu layer 3, the intermediate layer 4, and the Au layer 5 are stacked is referred to as a region 10. That is, in the region other than the region 10 on the upper surface of the ceramic substrate 100, the upper surface of the ceramic plate 1 is exposed. When the ceramic substrate 100 is used in a light-emitting device, a light-emitting element is suitably disposed on the region 10.

[0023] The planar shape of the region 10 in the ceramic substrate 100 is not particularly limited, but when the ceramic substrate 100 is used in a light emitting device, it is preferable that the shape corresponds to the electrode shape, layout, etc. of the light emitting element.

[0024] (Ceramics plate 1) The ceramic plate 1 is an insulating member that serves as a base for arranging the seed layer 2, the Cu layer 3, the intermediate layer 4, and the Au layer 5. The ceramic plate 1 is preferably sintered and not in a softened state before sintering.

[0025] The shape of the ceramic plate 1 in a horizontal plan view is not particularly limited, and may be a circle, an ellipse, a polygon such as a square or a hexagon, a polygon with rounded corners, or a combination of these shapes. Among these, a square is preferred, and a rectangle is more preferred. The shape and dimensions of the ceramic plate 1 in a plan view can be adjusted appropriately depending on the required performance, such as the dimensions and number of the Cu layer 3 to be disposed thereon.

[0026] The upper surface of the ceramic plate 1 may or may not be flat, but a flat surface is preferable in that when the ceramic substrate 100 is used in a light emitting device, a light emitting element can be suitably arranged.

[0027] The lower surface of the ceramic plate 1 is the surface of the ceramic plate 1 opposite to the upper surface on which the Cu layer 3 and the like are arranged. The lower surface of the ceramic plate 1 may or may not be flat, but a flat surface is preferable because when the ceramic substrate 100 is used in a light emitting device, it can be suitably arranged on a mounting substrate.

[0028] The upper and lower surfaces of the ceramic plate 1 are, for example, parallel to each other. Here, when describing the surfaces of the ceramic plate 1 as "parallel," a difference of ±5 degrees is permitted.

[0029] The material of the ceramic plate 1 is not particularly limited as long as it is an insulating material, but a material that is difficult for light from the light-emitting element and external light to transmit when the ceramic substrate 100 is used in a light-emitting device is preferred. Examples of materials for such ceramic plate 1 include nitride-based ceramics such as aluminum nitride, 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 alone or in combination of two or more.

[0030] The ceramic plate 1 preferably contains these insulating materials as its main material, and may further contain other secondary materials as necessary. Here, the "main material" refers to the material that has the largest amount of substance among the materials constituting the ceramic plate 1.

[0031] The secondary material in the ceramic plate 1 is not particularly limited, and may be, for example, glass.

[0032] The average thickness of the ceramic plate 1 is not particularly limited, but is preferably 100 μm or more and 1,000 μm or less, and more preferably 120 μm or more and 500 μm or less.

[0033] The average thickness of the ceramic plate 1 is determined by measuring the thickness at two points arbitrarily selected from the corner of the ceramic plate 1 and calculating the average of the two points. The thickness of the corner of the ceramic plate 1 is measured using a macro gauge.

[0034] (Seed layer 2) The seed layer 2 is disposed on the upper surface of the ceramic plate 1 .

[0035] In the horizontal direction, the edge 2a of the upper surface of the seed layer 2 is located outside the edge 3b of the lower surface of the Cu layer 3. In the horizontal direction, the edge 2a of the upper surface of the seed layer 2 is preferably located outside the edge 3b of the lower surface of the Cu layer 3 by 1 μm to 5 μm, and more preferably by 1.2 μm to 3 μm. The inner region surrounded by the edge 3b of the lower surface of the Cu layer 3 is defined as the inside of the edge 3b of the lower surface of the Cu layer 3, and the outer region surrounded by the edge 3b of the lower surface of the Cu layer 3 is defined as the outside of the edge 3b of the lower surface of the Cu layer 3. When the edge 2a of the upper surface of the seed layer 2 is located outside the edge 3b of the lower surface of the Cu layer 3 in the horizontal direction, corrosion on the lower surface of the Cu layer 3 can be suppressed, resulting in a ceramic substrate 100 with excellent reliability.

[0036] Furthermore, it is preferable that the edge 2a of the upper surface of the seed layer 2 is located more inward than the edge 5b of the lower surface of the Au layer 5 in the horizontal direction. Specifically, it is preferable that the edge 2a of the upper surface of the seed layer 2 is located more inward than the edge 5b of the lower surface of the Au layer 5 in the horizontal direction by 1.0 μm to 5.0 μm, and more preferably by 1.2 μm to 3 μm. The inner region surrounded by the edge 5b of the lower surface of the Au layer 5 is defined as the inner region of the edge 5b of the lower surface of the Au layer 5, and the outer region surrounded by the edge 5b of the lower surface of the Au layer 5 is defined as the outer region of the edge 5b of the lower surface of the Au layer 5. When the edge 2a of the upper surface of the seed layer 2 is located more inward than the edge 5b of the lower surface of the Au layer 5 in the horizontal direction, corrosion of the lower surface of the Cu layer 3 can be suitably suppressed, resulting in a ceramic substrate 100 with improved reliability.

[0037] Furthermore, the side surfaces of the seed layer 2 are preferably exposed from the Au layer 5. The side surfaces of the seed layer 2 are surfaces that connect the upper and lower surfaces of the seed layer 2 when the ceramic substrate 100 is viewed in cross section.

[0038] In the ceramic substrate 100 according to the first embodiment, the entire lower surface of the intermediate layer 4 is in contact with the upper surface of the seed layer 2. As a result, in a plan view in the horizontal direction, an edge 2a of the upper surface of the seed layer 2 and an edge 4b ​​of the lower surface of the intermediate layer 4 coincide with each other, but this is not limiting.

[0039] For example, only a portion of the lower surface of the intermediate layer 4 may be in contact with the upper surface of the seed layer 2, and the other portion of the lower surface of the intermediate layer 4 may not be in contact with the upper surface of the seed layer 2, but the other portion of the lower surface of the intermediate layer 4 is covered with the Au layer 5. In this case, in a plan view in the horizontal direction, the edge 2a of the upper surface of the seed layer 2 is located inside the edge 4b ​​of the lower surface of the intermediate layer 4. That is, the edge 2a of the upper surface of the seed layer 2 is located outside the edge 3b of the lower surface of the Cu layer 3 and inside the edge 4b ​​of the lower surface of the intermediate layer 4. The inner region surrounded by the edge 4b ​​of the lower surface of the intermediate layer 4 is defined as the inside of the edge 4b ​​of the lower surface of the intermediate layer 4, and the outer region surrounded by the edge 4b ​​of the lower surface of the intermediate layer 4 is defined as the outside of the edge 4b ​​of the lower surface of the intermediate layer 4.

[0040] Furthermore, for example, the entire lower surface of the intermediate layer 4 and the entire lower surface of the Au layer 5 may be in contact with the upper surface of the seed layer 2. In this case, in a plan view in the horizontal direction, the edge 2a of the upper surface of the seed layer 2 and the edge 5b of the lower surface of the Au layer 5 coincide with each other, or the edge 2a of the upper surface of the seed layer 2 is located outside the edge 5b of the lower surface of the Au layer 5.

[0041] Furthermore, for example, as long as the entire lower surface of the intermediate layer 4 and a portion of the lower surface of the Au layer 5 are in contact with the upper surface of the seed layer 2, the other portion of the lower surface of the Au layer 5 does not have to be in contact with the upper surface of the seed layer 2. In this case, in a plan view in the horizontal direction, the edge 2a of the upper surface of the seed layer 2 is located outside the edge 4b ​​of the lower surface of the intermediate layer 4 and inside the edge 5b of the lower surface of the Au layer 5. In other words, the edge 2a of the upper surface of the seed layer 2 is located outside the edge 3b of the lower surface of the Cu layer 3, outside the edge 4b ​​of the lower surface of the intermediate layer 4, and inside the edge 4b ​​of the lower surface of the intermediate layer 4.

[0042] The planar shape and dimensions of the seed layer 2 in the horizontal direction are not particularly limited as long as the edge 2a of the upper surface of the seed layer 2 is outside the edge 3b of the lower surface of the Cu layer 3, and when the ceramic substrate 100 is used in a light-emitting device, they can be appropriately adjusted depending on the shape, dimensions, and number of light-emitting elements to be placed on the region 10.

[0043] The material of the seed layer 2 is not particularly limited, but is preferably a conductive material, such as Ti, Cu, Au, Ru, TiNi, TiW, CuNi, or NiCr. These materials may be used alone or in combination. Among these, the seed layer 2 is preferably one or more selected from the group consisting of a Ti layer, a Cu layer, an Au layer, a Ru layer, a TiNi layer, a TiW layer, a CuNi layer, and a NiCr layer. More preferably, the seed layer 2 is one or more selected from the group consisting of a Ti layer and a Cu layer, a Ti layer and an Au layer, a Ti layer and a TiNi layer, a Ti layer and a TiW layer, a Ti layer, a TiW layer and a Cu layer, a Ti layer, a Ru layer and a Cu layer, a TiW layer, a CuNi layer, and a NiCr layer. Using these materials for the seed layer 2 provides excellent adhesion to the Cu layer 3, thereby suppressing corrosion of the Cu layer 3 and improving reliability.

[0044] The average thickness of the seed layer 2 is not particularly limited, but is preferably 0.1 μm to 2.0 μm, and more preferably 0.3 μm to 1 μm. When the average thickness of the seed layer 2 is 0.1 μm to 2.0 μm, the lower surfaces of the intermediate layer 4 and the Au layer 5 can be prevented from contacting the ceramic plate 1, so no gaps are formed around the Cu layer 3, corrosion of the Cu layer 3 can be suppressed, and the ceramic substrate 100 can be made highly reliable.

[0045] The average thickness of the seed layer 2 is determined by photographing a cross section of the ceramic substrate 100 in the Z-axis direction in the region including the seed layer 2 using a scanning electron microscope (SEM), measuring the thickness of the seed layer 2 at three arbitrarily selected locations within the field of view of the SEM image (for example, one location from the center and two locations from the edge), and calculating the average of the three locations.

[0046] (Cu layer 3) The Cu layer 3 is disposed on the upper surface of the seed layer 2. The lower surface of the Cu layer 3 is covered with the seed layer 2, and the side and upper surfaces of the Cu layer 3 are covered with the intermediate layer 4. Because the upper surface of the seed layer 2 and the intermediate layer 4 are in contact with each other, the Cu layer 3 is entirely covered with the seed layer 2 and the intermediate layer 4. Therefore, the Cu layer 3 is not affected by the external environment such as air, and corrosion can be suppressed, resulting in a highly reliable ceramic substrate 100.

[0047] The shape of the Cu layer 3 in a horizontal plan view is not particularly limited, and may be a circle, an ellipse, a polygon such as a square or a hexagon, a polygon with rounded corners, or a combination of these shapes. When the ceramic substrate 100 is used in a light-emitting device, the shape and dimensions of the Cu layer 3 in a plan view can be adjusted appropriately depending on the shape, dimensions, and number of light-emitting elements to be arranged on the region 10.

[0048] The average thickness of the Cu layer 3 is not particularly limited, but is preferably 10 μm or more and 60 μm or less, and more preferably 15 μm or more and 30 μm or less.

[0049] The average thickness of the Cu layer 3 is determined by photographing a cross section of the ceramic substrate 100 in the Z-axis direction of the region including the Cu layer 3 using a scanning electron microscope (SEM), measuring the thickness of the Cu layer 3 at three arbitrarily selected locations within the field of view of the SEM image (for example, one location from the center and two locations from the edge), and calculating the average of the three locations.

[0050] (Middle Class 4) The intermediate layer 4 is disposed on the upper surface and side surfaces of the Cu layer 3. In the ceramic substrate 100 according to the first embodiment, the intermediate layer 4 is a single layer. The upper surface of the seed layer 2 and the intermediate layer 4 are in contact with each other. The intermediate layer 4 can improve the adhesion between the Cu layer 3 and the Au layer 5.

[0051] The shape and dimensions of the intermediate layer 4 in a horizontal planar view can be adjusted appropriately to match the shape and dimensions of the Cu layer 3 in a planar view.

[0052] The material for the intermediate layer 4 is not particularly limited, but is preferably a conductive material, such as Ti, Ni, Pd, Pt, Rh, W, or Ru. These may be used alone or in combination of two or more. Among these, the material for the intermediate layer 4 preferably contains Ni or Pd. When the intermediate layer 4 is formed by electroless plating, Ni, NiP, NiB, Pd, or the like is preferred.

[0053] The average thickness of the intermediate layer 4 is not particularly limited, but is preferably 0.03 μm or more and 1 μm or less, and more preferably 0.05 μm or more and 0.1 μm or less.

[0054] The average thickness of the intermediate layer 4 is determined by photographing a cross section of the ceramic substrate 100 in the Z-axis direction of the region including the intermediate layer 4 using a scanning electron microscope (SEM), measuring the thickness of the intermediate layer 4 at three arbitrarily selected locations within the field of view of the SEM image (for example, one location from the center and two locations from the edge), and calculating the average of the three locations.

[0055] (Au layer 5) The Au layer 5 is disposed on the upper surface and side surfaces of the intermediate layer 4. The upper surface of the ceramic plate 1 and the Au layer 5 are not in contact with each other. The Au layer 5 is the outermost layer in the region 10.

[0056] By forming the Au layer 5 on the outermost surface of region 10, the reliability of connection with the light-emitting element is improved when ceramic substrate 100 is used in a light-emitting device. Since gold is usually used for the electrodes of light-emitting elements, the connection between Au layer 5 in region 10 and the Au electrode of the light-emitting element is highly reliable, and therefore, it is possible to maintain a highly reliable connection for a long period of time without deterioration even when a high voltage is applied.

[0057] The shape and dimensions of the Au layer 5 in a horizontal plane view can be adjusted appropriately to match the shapes and dimensions of the Cu layer 3 and the intermediate layer 4 in a plane view.

[0058] The average thickness of the Au layer 5 is not particularly limited, but is preferably 0.03 μm or more and 1 μm or less, and more preferably 0.05 μm or more and 0.1 μm or less.

[0059] The average thickness of the Au layer 5 is determined by photographing a cross section of the ceramic substrate 100 in the Z-axis direction in the region including the Au layer 5 using a scanning electron microscope (SEM), measuring the thickness of the Au layer 5 at three arbitrarily selected locations within the field of view of the SEM image (for example, one location from the center and two locations from the edge), and calculating the average of the three locations.

[0060] (Other configurations) Other components of the ceramic substrate 100 include, for example, a wiring section and a heat dissipation section that are different from the region 10 and a pad section 11 described later.

[0061] When the ceramic substrate 100 is used in a light-emitting device, it may further have wiring sections between the multiple regions 10 for electrical connection with the light-emitting elements, depending on the number of light-emitting elements to be mounted. For example, one or more relay wiring sections may be arranged between a pair of regions 10. The shape and arrangement of the wiring sections arranged between the pair of regions 10 may be determined depending on the shape of the pair of regions 10, its power supply control, etc., so that the multiple light-emitting elements are driven independently, or so that they are driven in series, parallel, or a combination thereof.

[0062] The ceramic substrate 100 may have a heat dissipation portion on the lower surface of the ceramic plate 1. The heat dissipation portion is preferably provided so as to overlap the region directly below the region 10 where the light emitting element is arranged in a horizontal plan view. The heat dissipation portion preferably has a larger planar shape. There are no particular restrictions on the shape, structure, and dimensions of the heat dissipation portion, and they can be selected appropriately depending on the purpose. The heat dissipation portion can be made of the same metal material as the region 10.

[0063] Second Embodiment 2 is a schematic cross-sectional view showing an example of a ceramic substrate according to the second embodiment. The ceramic substrate 100 according to the second embodiment has the same configuration as the ceramic substrate 100 according to the first embodiment, except that the intermediate layer 4 is made up of two layers, a first intermediate layer 4-1 and a second intermediate layer 4-2.

[0064] The first intermediate layer 4-1 and the second intermediate layer 4-2 are made of different materials. The first intermediate layer 4-1 is preferably made of Ni. The second intermediate layer 4-2 is preferably made of Pd.

[0065] In the ceramic substrate 100 of the second embodiment, the Ni layer which is the first intermediate layer 4-1 is arranged on the upper surface of the Cu layer 3 and on the side of the Cu layer 3, the Pd layer which is the second intermediate layer 4-2 is arranged on the upper surface of the Ni layer which is the first intermediate layer 4-1 and on the side of the Ni layer which is the first intermediate layer 4-1, and the Au layer 5 is arranged on the upper surface of the Pd layer which is the second intermediate layer 4-2 and on the side of the Pd layer which is the second intermediate layer 4-2.

[0066] Here, the entire lower surface of the first intermediate layer 4-1 and the entire lower surface of the second intermediate layer 4-2 are both in contact with the upper surface of the seed layer 2, but this is not limited to this. For example, only the entire lower surface of the first intermediate layer 4-1 may be in contact with the upper surface of the seed layer 2, and the lower surface of the second intermediate layer 4-2 may not be in contact with the upper surface of the seed layer 2, or the entire lower surface of the first intermediate layer 4-1 and a portion of the lower surface of the second intermediate layer 4-2 may be in contact with the upper surface of the seed layer 2, or only a portion of the lower surface of the first intermediate layer 4-1 may be in contact with the upper surface of the seed layer 2, and the other portion of the lower surface of the first intermediate layer 4-1 and the entire lower surface of the second intermediate layer 4-2 may not be in contact with the upper surface of the seed layer 2.

[0067] Although the ceramic substrate 100 according to the second embodiment will be described as having two intermediate layers 4, the ceramic substrate 100 according to the embodiment of the present disclosure may have three or more intermediate layers 4. When the ceramic substrate 100 has three or more intermediate layers 4, the material of each intermediate layer 4 is not particularly limited and can be appropriately selected depending on the purpose.

[0068] <Third embodiment> 3 is a schematic cross-sectional view showing an example of a ceramic substrate according to Embodiment 3. The ceramic substrate 100 according to Embodiment 3 has the same configuration as the ceramic substrate 100 according to Embodiment 1, except that the cross-sectional shape of the seed layer 2 is different.

[0069] In the ceramic substrate 100 of the third embodiment, a seed layer 2 is continuously arranged from the lower surface of the Cu layer 3 to a portion of the side surface of the Cu layer 3, and an intermediate layer 4 is arranged so as to cover the seed layer 2 arranged on a portion of the side surface of the Cu layer 3.

[0070] Here, "continuously arranged" the seed layer 2 means that the seed layer 2 is arranged without interruption not only in the horizontal direction of the XY plane but also in the Z-axis direction, which is the stacking direction. As a result, compared to the ceramic substrate 100 according to the first embodiment, there is no boundary between the lower surface of the intermediate layer 4 and the upper surface of the seed layer 2 on the lower surface of the Cu layer 3, which more reliably prevents the Cu layer 3 from coming into contact with the external environment, such as air, and more reliably suppresses corrosion, resulting in a ceramic substrate 100 with superior reliability.

[0071] <Fourth embodiment> 4A is a schematic top view showing an example of a ceramic substrate according to Embodiment 4. The ceramic substrate 100 according to Embodiment 4 has the same configuration as the ceramic substrate 100 according to Embodiment 1, except that it further includes a pad portion 11 electrically connected to the Au layer 5.

[0072] (Pad section 11) The layer structure of the pad portion 11 is not particularly limited as long as it can be electrically connected to the Au layer 5 in the region 10, and can be appropriately selected depending on the purpose. As examples of the pad portion 11, the pad portion 11A of the ceramic substrate 100 according to embodiment 4-1 and the pad portion 11B of the ceramic substrate 100 according to embodiment 4-2 will be described below. A single ceramic substrate 100 may have only one of the pad portion 11A and the pad portion 11B, or may have both at the same time in separate regions.

[0073] The shape of the pad portion 11 in a horizontal plan view is not particularly limited, but it is preferable that it extends from the region 10 and is disposed near the edge of the ceramic substrate 100. By increasing the total planar area of ​​the region 10 and the pad portion 11, when the ceramic substrate 100 is used in a light-emitting device, a light-emitting device can be obtained in which current flows easily and electrical resistance is low. Here, "near the edge of the ceramic substrate 100" means that the distance from the outer edge of the ceramic plate 1 on the surface where the region 10 and the pad portion 11 are disposed to the region 10 or the pad portion 11 is 0.01 mm or more and 0.5 mm or less.

[0074] Furthermore, by arranging the region 10 and the pad portion 11 near the end of the ceramic substrate 100, the connection length of the power supply member, for example, a wire, used to supply power to the external connection portion can be shortened, thereby ensuring reliable and easy power supply. Among these, it is preferable that the shape of the pad portion 11 in a horizontal plan view is such that, for the ceramic substrate 100 having a substantially rectangular shape in a horizontal plan view, the pair of positive and negative external connection portions each extend toward one side of the rectangle. This allows external power supply members to be connected in the same direction and with approximately the same length to both the positive and negative external connection portions.

[0075] <<Embodiment 4-1>> Fig. 4B is a schematic cross-sectional view in the lamination direction taken along line IVB-IVB in Fig. 4A. Fig. 4C is an enlarged cross-sectional view of a region IVC in Fig. 4B of the ceramic substrate according to embodiment 4-1.

[0076] The pad portion 11A in the ceramic substrate 100 according to embodiment 4-1 includes a ceramic plate 1, a seed layer 2 disposed on the upper surface of the ceramic plate 1, an intermediate layer 4 disposed on the upper surface of the seed layer 2, and an Au layer 5 disposed on the upper surface of the intermediate layer 4. The pad portion 11A preferably does not include a Cu layer 3. This allows the thickness of the pad portion 11A to be thin. When the ceramic substrate 100 is used in a light-emitting device, the heat dissipation of the light-emitting element can be improved by disposing the Cu layer 3 only in the region 10 where the light-emitting element is disposed.

[0077] <<Embodiment 4-2>> FIG. 4D is an enlarged cross-sectional view of a region IVC of the ceramic substrate according to the embodiment 4-2 in FIG. 4B.

[0078] The pad portion 11B in the ceramic substrate 100 according to embodiment 4-2 includes a ceramic plate 1, a seed layer 2 disposed on the upper surface of the ceramic plate 1, and an Al layer 6 disposed on the upper surface of the seed layer 2. The pad portion 11B preferably does not include a Cu layer 3. This allows the thickness of the pad portion 11B to be reduced. When the ceramic substrate 100 is used in a light-emitting device, the heat dissipation of the light-emitting element can be improved by disposing the Cu layer 3 only in the region 10 where the light-emitting element is disposed. Furthermore, when Al is used for the wire, the wire can be made of the same material as the surface of the pad portion 11B, which prevents fracture or disconnection between the wire and the pad portion 11B.

[0079] (Heat dissipation part 13) 4E is a schematic bottom view showing an example of the ceramic substrate according to the fourth embodiment. The heat dissipation portion 13 can have a shape that combines multiple shapes in which a rectangular pattern is cut out in a comb shape, for example.

[0080] [Method for manufacturing ceramic substrate] First Embodiment Fig. 5 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 described with reference to Figs. 6A to 6J.

[0081] A method for manufacturing a ceramic substrate according to a first embodiment includes: providing a first resist layer on the upper surface of a ceramic plate; exposing and developing the first resist layer to a predetermined shape; arranging a seed layer on the upper surface of the ceramic plate exposed from the first resist layer after exposure and development, on the side surface of the first resist layer, and on the upper surface of the first resist layer; providing a second resist layer so as to cover at least a portion of the upper surface of the seed layer; exposing and developing the second resist layer to a predetermined shape so that at least a portion of the upper surface of the seed layer disposed on the upper surface of the ceramic plate is exposed; arranging a Cu layer by electroplating on the upper surface of the seed layer exposed from the second resist layer after exposure and development; removing a portion of the seed layer, the first resist layer, and the second resist layer;

[0082] (S1) Exposing and developing the first resist layer into a predetermined shape Fig. 6A 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. Fig. 6B is a schematic cross-sectional view showing an example of providing a first resist layer in the method for manufacturing a ceramic substrate according to the first embodiment. Fig. 6C is a schematic cross-sectional view showing an example of exposing and developing the first resist layer into a predetermined shape in the method for manufacturing a ceramic substrate according to the first embodiment.

[0083] In step S1 of exposing and developing the first resist layer into a predetermined shape, a first resist layer 50 is provided on the upper surface of the ceramic plate 1, and the first resist layer 50 is exposed and developed into a predetermined shape.

[0084] Specifically, in step S1 of exposing and developing the first resist layer into a predetermined shape, first, a ceramic plate 1 is prepared. The ceramic plate 1 may be a ceramic precursor before sintering or a sintered ceramic, but a sintered ceramic is preferred because there is no change in size due to sintering.

[0085] Next, a first resist layer 50 is provided on the upper surface of the ceramic plate 1. At this time, the first resist layer 50 may be provided on the entire upper surface of the ceramic plate 1, or may be provided on only a part of the upper surface of the ceramic plate 1. The position on the upper surface of the ceramic plate 1 where the first resist layer 50 is provided can be appropriately selected depending on the desired position on the upper surface of the ceramic plate 1 where the region 10 is to be provided.

[0086] The first resist layer 50 is not particularly limited and can be formed using a photoresist composition, sheet-like resist (dry film resist), or the like commonly used in the technical field of light-emitting devices. Specifically, the first resist layer 50 can be formed using photoresist compositions made of various materials, such as those classified as novolac-diazonaphthoquinone (DNQ)-based photoresists, positive photoresists, negative photoresists, chemically amplified photoresists, photocrosslinkable photoresists, and photopolymerizable photoresists, or dry film resists formed from these photoresist compositions. Any commercially available photoresist composition or dry film resist can be used. Among these, it is preferable to form the first resist layer 50 using a negative photoresist.

[0087] Examples of methods for forming the first resist layer 50 using a photoresist composition include screen coating, spin coating, roll coating, laminator coating, dip coating, and spray coating.

[0088] Next, the first resist layer 50 can be formed into a predetermined shape using, for example, photolithography and etching. When a negative photoresist is used, for example, the first resist layer 50 is exposed to light using a mask having an opening of a desired shape corresponding to the region 10.

[0089] The exposure dose is not particularly limited, and is preferably set appropriately within the range of about 10 mJ to 50 mJ. Before or after exposure, baking may be performed at any temperature for any time.

[0090] Thereafter, the first resist layer 50 is patterned into a predetermined shape by immersion development or spray development using a developer that dissolves the resist present in the unexposed portions of the first resist layer 50 .

[0091] The developer used here can be appropriately selected depending on the type of resist used, and examples thereof include tetramethylammonium hydroxide (TMAH) and tetrabutylammonium hydroxide (TBAH).

[0092] (S2) Placing a seed layer FIG. 6D is a schematic cross-sectional view showing an example of arranging a seed layer in the method for manufacturing a ceramic substrate according to the first embodiment.

[0093] In the step S2 of disposing the seed layer, a seed layer 2 is disposed on the upper surface of the ceramic plate 1 exposed from the first resist layer 50 after exposure and development, the side surfaces of the first resist layer 50, and the upper surface of the first resist layer 50.

[0094] The seed layer 2 can be formed by a method known in the art, such as electrolytic plating, electroless plating, vapor deposition, or sputtering, using the material of the seed layer 2.

[0095] The average thickness of the seed layer 2 can be adjusted by the amount of material applied for the seed layer 2. In the step S2 of disposing the seed layer, the seed layer 2 is preferably disposed to have a thickness of 1.0 μm or more and 5.0 μm or less, and more preferably disposed to have a thickness of 1.2 μm or more and 3.0 μm or less.

[0096] (S3) Exposing and developing the second resist layer into a predetermined shape. Fig. 6E is a schematic cross-sectional view showing an example of providing a second resist layer in the method for manufacturing a ceramic substrate according to Embodiment 1. Fig. 6F is a schematic cross-sectional view showing an example of exposing and developing the second resist layer into a predetermined shape in the method for manufacturing a ceramic substrate according to Embodiment 1.

[0097] The step S3 of exposing and developing the second resist layer into a predetermined shape involves providing a second resist layer 51 so as to cover at least a portion of the upper surface of the seed layer 2, and exposing and developing the second resist layer 51 into a predetermined shape so that at least a portion of the upper surface of the seed layer 2 arranged on the upper surface of the ceramic plate 1 is exposed.

[0098] The position at which the second resist layer 51 is provided can be appropriately selected on the upper surface of the seed layer 2 depending on the desired position at which the region 10 is to be provided, but it is preferable to provide the second resist layer 51 at a position where at least the first resist layer 50 can be removed simultaneously when the second resist layer 51 is removed.

[0099] The second resist layer 51 is not particularly limited and can be formed using a photoresist composition that is commonly used in the technical field of light-emitting devices, for example, the same as that used for the first resist layer 50. Among these, it is preferable that the second resist layer 51 be formed using a negative photoresist.

[0100] Examples of methods for forming the second resist layer 51 using a photoresist composition include screen coating, spin coating, roll coating, laminator coating, dip coating, and spray coating.

[0101] Next, the second resist layer 51 can be formed into a predetermined shape using, for example, photolithography and etching. When a negative photoresist is used, for example, the second resist layer 51 is exposed using a mask having an opening of a desired shape corresponding to the region 10. For example, by masking so that the second resist layer 51 is formed on the seed layer 2 arranged on the first resist layer 50, in step S5 of removing a portion of the seed layer, the first resist layer, and the second resist layer, which will be described later, the first resist layer 50, the second resist layer 51, and the seed layer 2 between the first resist layer 50 and the second resist layer 51 can be simultaneously removed.

[0102] The exposure dose is not particularly limited, and is preferably set appropriately within the range of about 10 mJ to 50 mJ. Before or after exposure, baking may be performed at any temperature for any time.

[0103] Thereafter, the second resist layer 51 is patterned into a predetermined shape by immersion development or spray development using a developer that dissolves the resist present in the unexposed areas of the second resist layer 51.

[0104] The developer used here can be appropriately selected depending on the type of resist used, and examples thereof include tetramethylammonium hydroxide (TMAH) and tetrabutylammonium hydroxide (TBAH).

[0105] In the method for manufacturing a ceramic substrate according to the first embodiment, in step S3 of exposing and developing the second resist layer into a predetermined shape, it is preferable to perform exposure and development so that at least a portion of the upper surface of the seed layer 2 arranged on the upper surface of the ceramic plate 1 is exposed from the second resist layer 51, without exposing the side surfaces of the first resist layer 50 and the seed layer 2 arranged on the upper surface of the first resist layer 50. In other words, it is preferable to remove the second resist layer 51 between adjacent first resist layers 50.

[0106] (S4) Placing a Cu layer FIG. 6G is a schematic cross-sectional view showing an example of arranging a Cu layer in the method for manufacturing a ceramic substrate according to the first embodiment.

[0107] In S4, a Cu layer is formed by electrolytic plating on the upper surface of the seed layer 2 that has been exposed and developed and is now exposed from the second resist layer 51. The average thickness of the Cu layer 3 can be adjusted by adjusting the amount of plating solution containing Cu that is applied. In this case, the seed layer 2 is not formed on the side surfaces of the Cu layer 3.

[0108] The plating solution contains, for example, Cu particles and a solvent, and may further contain a resin, etc., as necessary. The plating solution is bonded to the seed layer 2.

[0109] (S5) Removing a portion of the seed layer, the first resist layer, and the second resist layer. FIG. 6H is a schematic cross-sectional view showing an example of removing a part of the seed layer, the first resist layer, and the second resist layer in the method for manufacturing a ceramic substrate according to the first embodiment.

[0110] In step S5 of removing a portion of the seed layer, the first resist layer, and the second resist layer, it is preferable to completely remove the first resist layer 50 and the second resist layer 51. Examples of the portion of the seed layer 2 include the seed layer 2 between the first resist layer 50 and the second resist layer 51 and the seed layer 2 disposed on the side surface of the first resist layer 50. This forms a laminated structure of the ceramic plate 1, the seed layer 2, and the Cu layer 3 having a predetermined shape.

[0111] The part of the seed layer 2, the first resist layer 50, and the second resist layer 51 can be removed by, for example, a lift-off method. A stripping solution, for example, can be used as the solvent used in the lift-off method. For example, the part of the seed layer 2, the first resist layer 50, and the second resist layer 51 are all removed by ultrasonic cleaning.

[0112] (S6) Placing the middle layer FIG. 6I is a schematic cross-sectional view showing an example of arranging an intermediate layer in the method for manufacturing a ceramic substrate according to the first embodiment.

[0113] In the step S6 of disposing the intermediate layer, one intermediate layer 4 is disposed on the upper surface of the Cu layer 3 and on the side surfaces of the Cu layer 3. The intermediate layer 4 is preferably disposed so as to cover the upper surface of the seed layer 2 disposed on the upper surface of the ceramic plate 1. The average thickness of the intermediate layer 4 can be adjusted by the amount of material applied for the intermediate layer 4.

[0114] The intermediate layer 4 can be formed by a method known in the art, such as electrolytic plating, electroless plating, vapor deposition, or sputtering.

[0115] (S7) Placing the Au layer FIG. 6J is a schematic cross-sectional view showing an example of arranging an Au layer in the method for manufacturing a ceramic substrate according to the first embodiment.

[0116] In disposing the Au layer S7, the Au layer 5 is disposed on the upper surface and side surfaces of the intermediate layer 4. Specifically, the Au layer 5 can be formed by applying the material for the Au layer 5 from above and from the sides of the intermediate layer 4. The average thickness of the Au layer 5 can be adjusted by adjusting the amount of the material for the Au layer 5 applied.

[0117] The Au layer 5 can be formed by a method known in the art, such as electrolytic plating, electroless plating, vapor deposition, or sputtering.

[0118] By the above method, a ceramic substrate 100 is formed, which comprises a ceramic plate 1, a seed layer 2 arranged on the upper surface of the ceramic plate 1, a Cu layer 3 arranged on the upper surface of the seed layer 2, one intermediate layer 4 arranged on the upper surface of the Cu layer 3 and on the side of the Cu layer 3, and an Au layer 5 arranged on the upper surface of the intermediate layer 4 and on the side of the intermediate layer 4, wherein the upper surface of the seed layer 2 is in contact with the intermediate layer 4, the upper surface of the ceramic plate 1 is not in contact with the Au layer 5, and in the horizontal direction, the edge 2a of the upper surface of the seed layer 2 is outside the edge 3b of the lower surface of the Cu layer 3, and the edge 2a of the upper surface of the seed layer 2 is inside the edge 5b of the lower surface of the Au layer 5.

[0119] In the method for manufacturing a ceramic substrate according to the first embodiment, in the finally formed ceramic substrate 100, an edge 2a of the upper surface of the seed layer 2 is located outside an edge 3b of the lower surface of the Cu layer 3, and therefore the upper surface of the seed layer 2 and the lower surface of the intermediate layer 4 come into contact with each other, completely covering the Cu layer 3 with the seed layer 2 and the intermediate layer 4. This makes it possible to suppress corrosion on the lower surface of the Cu layer 3, resulting in a ceramic substrate 100 with excellent reliability.

[0120] Second Embodiment Fig. 7 is a flowchart showing an example of a method for manufacturing a ceramic substrate according to the second embodiment. The method for manufacturing a ceramic substrate according to the second embodiment will be described with reference to Figs. 8A to 8C.

[0121] The method for manufacturing a ceramic substrate according to the second embodiment is the same as the method for manufacturing a ceramic substrate according to the first embodiment, except that two or more intermediate layers 4 are formed.

[0122] (S16) Placing the first intermediate layer FIG. 8A is a schematic cross-sectional view showing an example of arranging a first intermediate layer in the method for manufacturing a ceramic substrate according to the second embodiment.

[0123] In the step S16 of disposing the first intermediate layer, the first intermediate layer 4-1 is disposed on the upper surface of the Cu layer 3 and on the side surface of the Cu layer 3. The average thickness of the first intermediate layer 4-1 can be adjusted by the amount of material applied for the first intermediate layer 4-1.

[0124] The material of the first intermediate layer 4-1 can be selected as appropriate, but in disposing the first intermediate layer S16, it is preferable to dispose a Ni layer as the first intermediate layer 4-1 on the upper surface of the Cu layer 3 and on the side surface of the Cu layer 3.

[0125] (S17) Placing the second intermediate layer FIG. 8B is a schematic cross-sectional view showing an example of arranging a second intermediate layer in the method for manufacturing a ceramic substrate according to the second embodiment.

[0126] In step S17 of disposing the second intermediate layer, the second intermediate layer 4-2 is disposed on the upper surface of the first intermediate layer 4-1 and on the side surface of the first intermediate layer 4-1. The average thickness of the second intermediate layer 4-2 can be adjusted by the amount of material applied for the second intermediate layer 4-2.

[0127] The material of the second intermediate layer 4-2 can be selected appropriately, but in S17 of arranging the second intermediate layer 4-2, it is preferable to arrange a Pd layer as the second intermediate layer 4-2 on the upper surface of the Ni layer as the first intermediate layer 4-1 and on the side of the Ni layer as the first intermediate layer 4-1.

[0128] (S18) Placing the Au layer FIG. 8C is a schematic cross-sectional view showing an example of arranging an Au layer in the method for manufacturing a ceramic substrate according to the second embodiment.

[0129] In the step S18 of disposing an Au layer, an Au layer 5 is disposed on the upper surface of the second intermediate layer 4-2 and on the side surface of the second intermediate layer 4-2. If the second intermediate layer 4-2 is a Pd layer, in the step S7-2 of disposing an Au layer, an Au layer 5 is disposed on the upper surface of the Pd layer serving as the second intermediate layer 4-2 and on the side surface of the Pd layer serving as the second intermediate layer 4-2.

[0130] The above method results in a ceramic substrate 100 having a ceramic plate 1, a seed layer 2 disposed on the upper surface of the ceramic plate 1, a Cu layer 3 disposed on the upper surface of the seed layer 2, a first intermediate layer 4-1 and a second intermediate layer 4-2 disposed on the upper surface of the Cu layer 3 and on the side surfaces of the Cu layer 3, and an Au layer 5 disposed on the upper surface of the second intermediate layer 4-2 and on the side surfaces of the second intermediate layer 4-2, where the upper surface of the seed layer 2 is in contact with the first intermediate layer 4-1 and the second intermediate layer 4-2. However, the upper surface of the ceramic plate 1 is not in contact with the Au layer 5. In the horizontal direction, an edge 2a of the upper surface of the seed layer 2 is outward from an edge 3b of the lower surface of the Cu layer 3, and the edge 2a of the upper surface of the seed layer 2 is inward from an edge 5b of the lower surface of the Au layer 5.

[0131] In the method for manufacturing a ceramic substrate according to the second embodiment, a case where the intermediate layer 4 is two-layered will be described, but in the ceramic substrate 100 according to the embodiment of the present disclosure, the intermediate layer 4 may be three or more layers. When three or more layers are used, a third intermediate layer, a fourth intermediate layer, etc. can be formed sequentially in the same manner as in S17 for disposing the second intermediate layer.

[0132] <Third embodiment> Fig. 9 is a flowchart showing an example of a method for manufacturing a ceramic substrate according to the third embodiment. The method for manufacturing a ceramic substrate according to the third embodiment will be described with reference to Figs. 10A to 10I.

[0133] The manufacturing method of the ceramic substrate according to the third embodiment is the same as the manufacturing method of the ceramic substrate according to the first embodiment, except that the predetermined shape of the first resist layer is made such that the length L1 of the lower surface of the first resist layer 50 in the cross section in the thickness direction of the ceramic plate 1 is shorter than the length L2 of the upper surface of the first resist layer 50, and a seed layer 2 is disposed on a part of the side surface of the Cu layer 3.

[0134] (S21) Exposing and developing the first resist layer into a predetermined shape FIG. 10A is a schematic cross-sectional view showing an example of exposing and developing the first resist layer into a predetermined shape in the manufacturing method of the ceramic substrate according to the third embodiment. FIG. 10B is an enlarged cross-sectional view of the region XB in FIG. 10A.

[0135] Exposing and developing the first resist layer into a predetermined shape S21 exposes and develops the first resist layer 50 such that the length L1 of the lower surface of the first resist layer 50 in the cross section in the thickness direction of the ceramic plate 1 is shorter than the length L2 of the upper surface of the first resist layer 50. That is, the length L1 of the lower surface of the first resist layer 50 and the length L2 of the upper surface of the first resist layer 50 satisfy L1 < L2.

[0136] For example, in exposing and developing the first resist layer 50 into a predetermined shape S21, the shape of the first resist layer 50 in the cross section in the thickness direction of the ceramic plate 1 has, in a cross-sectional view, a main portion 50A of the first resist layer that contacts the first region M on the upper surface of the ceramic plate 1, and a protruding portion 50B that protrudes from the main portion 50A onto the second region N without contacting the second region N on the upper surface of the ceramic plate 1 adjacent to the first region M. Thereby, a space S1 is formed between the upper surface of the ceramic plate 1 and the lower surface of the protruding portion 50B. Note that the length in the X-axis direction of the first region M on the upper surface of the ceramic plate 1 is the length L1 of the lower surface of the first resist layer 50.

[0137] (S22) Disposing the seed layer FIG. 10C is a schematic cross-sectional view showing an example of arranging a seed layer in the method for manufacturing a ceramic substrate according to the third embodiment.

[0138] In the step S22 of disposing the seed layer, the seed layer 2 is disposed so as to continuously cover the side surfaces of the first resist layer 50 and the upper surface of the ceramic plate 1 exposed from the first resist layer 50. Specifically, in the step S22 of disposing the seed layer, the seed layer 2 is exposed and developed, and disposed on the upper surface of the ceramic plate 1 exposed from the first resist layer 50, the side surfaces of the first resist layer 50, and the upper surface of the first resist layer 50, so that the seed layer 2 is also disposed in the space S1.

[0139] (S23) Exposing and developing the second resist layer into a predetermined shape. Fig. 10D is a schematic cross-sectional view showing an example of providing a second resist layer in the method for manufacturing a ceramic substrate according to the third embodiment. Fig. 10E is a schematic cross-sectional view showing an example of exposing and developing the second resist layer into a predetermined shape in the method for manufacturing a ceramic substrate according to the third embodiment.

[0140] In step S23 of exposing and developing the second resist layer into a predetermined shape, it is preferable to expose and develop the second resist layer so that the seed layer 2 arranged on the side surface of the first resist layer 50 is exposed.

[0141] (S24) Placing a Cu layer 10F is a schematic cross-sectional view showing an example of disposing a Cu layer in the method for manufacturing a ceramic substrate according to the third embodiment. In the method for manufacturing a ceramic substrate according to the third embodiment, in disposing a Cu layer S24, in addition to disposing a Cu layer 3 by electroplating on the upper surface of the seed layer 2 that has been exposed and developed and is exposed from the second resist layer 51, it is preferable to dispose a Cu layer 3 by electroplating on the seed layer 2 disposed on the side surface of the first resist layer 50. Since the seed layer 2 is continuously connected, the Cu layer 3 can be disposed by electroplating.

[0142] (S25) Removing a portion of the seed layer, the first resist layer, and the second resist layer. FIG. 10G is a schematic cross-sectional view showing an example of removing a part of the seed layer, the first resist layer, and the second resist layer in the method for manufacturing a ceramic substrate according to the third embodiment.

[0143] In removing a portion of the seed layer, the first resist layer, and the second resist layer S25, the seed layer 2 arranged on the upper surface of the first resist layer 50 and the lower surface of the second resist layer 51 is removed, but the seed layer 2 arranged on the side of the first resist layer 50 and the seed layer 2 arranged on the upper surface of the ceramic plate 1 and the lower surface of the first resist layer 50 are not removed.

[0144] (S26) Placing an intermediate layer FIG. 10H is a schematic cross-sectional view showing an example of arranging an intermediate layer in the method for manufacturing a ceramic substrate according to the third embodiment.

[0145] In disposing the intermediate layer S26, the intermediate layer 4 is disposed so as to cover the seed layer 2 disposed on the side surface of the Cu layer 3 and the upper surface of the Cu layer 3. The intermediate layer 4 is also disposed on the side surface of the Cu layer 3 that is not covered with the seed layer 2.

[0146] (S27) Placing the Au layer FIG. 10I is a schematic cross-sectional view showing an example of arranging an Au layer in the method for manufacturing a ceramic substrate according to the third embodiment.

[0147] The above method results in a ceramic substrate 100 having a ceramic plate 1, a seed layer 2 disposed on the upper surface of the ceramic plate 1, a Cu layer 3 disposed on the upper surface of the seed layer 2, one intermediate layer 4 disposed on the upper surface of the Cu layer 3 and on the side surfaces of the Cu layer 3, and an Au layer 5 disposed on the upper surface of the intermediate layer 4 and on the side surfaces of the intermediate layer 4, with the upper surface of the seed layer 2 being in contact with the intermediate layer 4. However, the upper surface of the ceramic plate 1 is not in contact with the Au layer 5. In the horizontal direction, an edge 2a of the upper surface of the seed layer 2 is outward from an edge 3b of the lower surface of the Cu layer 3, and inward from an edge 5b of the lower surface of the Au layer 5, the seed layer 2 is disposed continuously from the lower surface of the Cu layer 3 to a portion of the side surface of the Cu layer 3, and the intermediate layer 4 is disposed so as to cover the seed layer 2 disposed on a portion of the side surface of the Cu layer 3.

[0148] In the ceramic substrate 100 formed by the method for manufacturing a ceramic substrate according to the third embodiment, compared to the ceramic substrate 100 formed by the method for manufacturing a ceramic substrate according to the first embodiment, the seed layer 2 is disposed on part of the side surface of the Cu layer 3, and therefore no boundary is formed between the lower surface of the intermediate layer 4 and the upper surface of the seed layer 2 on the lower surface of the Cu layer 3, more reliably preventing contact between the Cu layer 3 and the external environment such as air. Furthermore, corrosion can be further suppressed, resulting in a ceramic substrate 100 with superior reliability.

[0149] <Fourth embodiment> Fig. 11 is a flowchart showing an example of a method for manufacturing a ceramic substrate according to the fourth embodiment. The method for manufacturing a ceramic substrate according to the fourth embodiment will be described with reference to Figs. 12A to 12I.

[0150] The method for manufacturing a ceramic substrate according to the fourth embodiment is the same as the method for manufacturing a ceramic substrate according to the third embodiment, except that the first resist layer 50 is formed so that the cross-sectional shape of the first resist layer 50 has an overhanging shape (also called an inverted tapered shape), that is, the first resist layer 50 is formed so that the cross-sectional shape of the first resist layer 50 decreases in width (length in the X-axis direction) of the first resist layer 50 from the top surface of the first resist layer 50 toward the bottom surface of the first resist layer 50, and that a seed layer 2 is not placed on the side surface of the Cu layer 3.

[0151] (S31) Exposing and developing the first resist layer into a predetermined shape. Fig. 12A is a schematic cross-sectional view showing an example of exposing and developing a first resist layer into a predetermined shape in a method for manufacturing a ceramic substrate according to Embodiment 4. Fig. 12B is an enlarged cross-sectional view of region XIIB in Fig. 12A.

[0152] In step S31 of exposing and developing the first resist layer 50 into a predetermined shape, the first resist layer is exposed and developed so that the shape of the first resist layer 50 in a cross section in the thickness direction of the ceramic plate 1 has, in cross section, a main portion 50A of the first resist layer that contacts a first region M on the upper surface of the ceramic plate 1, and a protruding portion 50B that protrudes from the main portion 50A onto a second region N on the upper surface of the ceramic plate 1 adjacent to the first region M without contacting the second region N. As a result, a space S2 is formed between the upper surface of the ceramic plate 1 and the lower surface of the protruding portion 50B.

[0153] (S32) Placing a seed layer FIG. 12C is a schematic cross-sectional view showing an example of arranging a seed layer in the method for manufacturing a ceramic substrate according to the fourth embodiment.

[0154] (S33) Exposing and developing the second resist layer into a predetermined shape. Fig. 12D is a schematic cross-sectional view showing an example of providing a second resist layer in the method for manufacturing a ceramic substrate according to the fourth embodiment. Fig. 12E is a schematic cross-sectional view showing an example of exposing and developing the second resist layer into a predetermined shape in the method for manufacturing a ceramic substrate according to the fourth embodiment.

[0155] In step S33 of exposing and developing the second resist layer into a predetermined shape, a sheet-like resist, specifically a dry film, is used as the second resist layer 51. By evacuating the dry film when using it, the air layer between the first resist layer 50 and the seed layer 2 and the second resist layer 51 can be removed, and the second resist layer 51 can also be provided in the space S2.

[0156] Next, the second resist layer 51 is exposed and developed so that the second resist layer 51 arranged on the upper surface of the seed layer 2 and the second resist layer 51 arranged on the side surface of the seed layer 2 in the space S2 remain. As a result, the seed layer 2 arranged on the upper surface of the ceramic plate 1 is exposed from the second resist layer 51.

[0157] However, instead of using a sheet-like resist as the second resist layer, a photoresist composition commonly used in the technical field of light-emitting devices may be used to form a second resist layer 51 on the top surface of the seed layer 2 disposed on the top surface of the ceramic plate 1, on the top surface of the seed layer 2 disposed on the top surface of the first resist layer 50, and on the side surfaces of the seed layer 2 disposed on the side surfaces of the first resist layer 50. In this case, the second resist layer 51 is also disposed above the ceramic plate 1, on the sides of the first resist layer 50 between adjacent first resist layers 50, and in the space S2. Next, the second resist layer 51 is exposed and developed so that the top surface of the ceramic plate 1 is exposed. As a result, the seed layer 2 disposed on the top surface of the ceramic plate 1 is exposed from the second resist layer 51. Note that "above the ceramic plate 1" does not mean that the ceramic plate 1 and the second resist layer 51 are in contact with each other; rather, the seed layer 2 is disposed between the ceramic plate 1 and the second resist layer 51. Furthermore, the side of the first resist layer 50 does not mean that the side of the first resist layer 50 and the second resist layer 51 are in contact with each other, but rather that a seed layer 2 is disposed between the side of the first resist layer 50 and the second resist layer 51.

[0158] (S34) Placing a Cu layer FIG. 12F is a schematic cross-sectional view showing an example of arranging a Cu layer in the method for manufacturing a ceramic substrate according to the fourth embodiment.

[0159] A plating solution containing Cu is applied from above the seed layer 2 exposed from the second resist layer 51 to form the Cu layer 3. At this time, the plating solution is not applied to the space S2 because the second resist layer 51 is disposed therein.

[0160] (S35) Removing a portion of the seed layer, the first resist layer, and the second resist layer. FIG. 12G is a schematic cross-sectional view showing an example of removing a part of the seed layer, the first resist layer, and the second resist layer in the method for manufacturing a ceramic substrate according to the fourth embodiment.

[0161] In S35, which is the removal of a portion of the seed layer, the first resist layer, and the second resist layer, the first resist layer 50, the seed layer 2 arranged on the upper surface of the first resist layer 50, the seed layer 2 arranged on the side of the first resist layer 50, the second resist layer 51 arranged on the upper surface of the seed layer 2 arranged on the upper surface of the first resist layer 50, and the second resist layer 51 arranged on the side of the seed layer 2 arranged on the side of the first resist layer 50 are removed.

[0162] (S36) Placing an intermediate layer FIG. 12H is a schematic cross-sectional view showing an example of arranging an intermediate layer in the method for manufacturing a ceramic substrate according to the fourth embodiment.

[0163] (S37) Placing the Au layer FIG. 12I is a schematic cross-sectional view showing an example of arranging an Au layer in the method for manufacturing a ceramic substrate according to the fourth embodiment.

[0164] The above method provides a ceramic substrate 100 having a ceramic plate 1, a seed layer 2 disposed on the upper surface of the ceramic plate 1, a Cu layer 3 disposed on the upper surface of the seed layer 2, one intermediate layer 4 disposed on the upper surface of the Cu layer 3 and on the side surfaces of the Cu layer 3, and an Au layer 5 disposed on the upper surface of the intermediate layer 4 and on the side surfaces of the intermediate layer 4, with the upper surface of the seed layer 2 and the intermediate layer 4 being in contact. The upper surface of the ceramic plate 1 and the Au layer 5 are not in contact, but may be in contact. A ceramic substrate 100 is formed such that the edge 2a of the upper surface of the seed layer 2 is located outside the edge 3b of the lower surface of the Cu layer 3 in the horizontal direction. By forming the first resist layer 50 to provide the space S2 in this manner, the area of ​​the seed layer 2 extending outward from the Cu layer 3 can be increased. The contact between the seed layer 2 and the Au layer 5 further suppresses corrosion on the lower surface of the Cu layer 3, resulting in a highly reliable ceramic substrate.

[0165] [Light-emitting device] The light emitting device 200 according to the embodiment includes the ceramic substrate 100 according to the embodiment and a light emitting element 20 disposed on the ceramic substrate 100. The light emitting device 200 according to the embodiment preferably further includes a reflective member 40 disposed on the upper surface of the ceramic substrate 100. The light emitting device 200 according to the embodiment may also include a bonding member 60 that electrically connects the light emitting element 20 to the ceramic substrate 100, a light-transmitting member 30 that is disposed on the upper surface of the light emitting element 20, and a frame 41 that surrounds the light emitting element 20 on the ceramic substrate 100.

[0166] Fig. 13A is a schematic top view showing an example of a light emitting device according to an embodiment. Fig. 13B is a schematic cross-sectional view in the stacking direction taken along line XIIIB-XIIIB in Fig. 13A. Fig. 13C is an enlarged cross-sectional view of region XIIIC in Fig. 13B. Fig. 13D is an enlarged cross-sectional view of region XIIID in Fig. 13C. Each component of light emitting device 200 will now be described.

[0167] The light emitting device 200 is a device that emits light by disposing a light emitting element 20 on a ceramic substrate 100. In the light emitting device 200, a region 10 of the ceramic substrate 100 where a seed layer 2, a Cu layer 3, an intermediate layer 4, and an Au layer 5 are stacked is an element mounting region where the light emitting element 20 is mounted.

[0168] In the light emitting device 200, the pad portion 11 of the ceramic substrate 100 serves as an external connection region for ensuring electrical connection with the outside of the light emitting device 200. The pad portion 11 is disposed outside the frame 41. In a plan view of the light emitting device 200, the boundary between the region 10 and the pad portion 11 is disposed inside the outer edge of the frame 41.

[0169] The frame 41 has a substantially rectangular shape in a plan view, and is formed so that three sides of the rectangle cover the region 10 or the pad portion 11.

[0170] Because the light emitting device 200 has the ceramic substrate 100, it is possible to arrange wiring layers made of different materials in the element mounting region 10 and the pad portion 11 in the external connection region. This allows the element mounting region to be a wiring layer suitable for the bonding material with the light emitting element 20, and the external connection region to be a wiring layer suitable for the external power supply member. This makes it possible to make the bonding between the light emitting element 20 and the ceramic substrate 100 and the bonding between the external power supply member and the ceramic substrate 100 stronger and more reliable.

[0171] (Light emitting element 20) The light emitting element 20 is preferably a light emitting diode. The composition of the light emitting element 20 is not particularly limited, and any composition can be used depending on the desired emission wavelength. For example, a nitride semiconductor (In 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 alone or in combination of two or more. The dimensions and shape of the light-emitting element 20 can be appropriately selected depending on the purpose of use.

[0172] The light-emitting element 20 is typically formed by stacking a semiconductor layer on a support substrate (e.g., a light-transmitting substrate such as sapphire). The support substrate may have irregularities on the surface where it is bonded to the semiconductor layer. This allows the critical angle at which light emitted from the semiconductor layer strikes the substrate to be intentionally changed, making it easier to extract the light outside the support substrate. The support substrate may be removed after the semiconductor layer is stacked. This can be done by, for example, polishing, LLO (Laser Lift Off), or the like.

[0173] The light emitting element 20 is mounted face down so that a pair of positive and negative electrodes is provided on the surface in contact with the ceramic substrate 100 .

[0174] When the light emitting element 20 is mounted face down, the light emitting element 20 can be flip-chip mounted on a mounting substrate. In this case, the surface of the light emitting element 20 opposite to the surface on which the pair of electrodes is formed becomes the main light extraction surface. In flip-chip mounting, the light emitting element 20 and the region 10 of the ceramic substrate 100 are electrically connected using a conductive paste-like bonding material such as solder, a thin-film bonding material, or a bump-like bonding material.

[0175] The outermost surfaces of the pair of positive and negative electrodes of the light-emitting element 20 are preferably made of Au. Au is chemically stable, and can ensure long-term reliability of electrical connection. Furthermore, since the outermost surface of the region 10 of the ceramic substrate is the Au layer 5, by using the same material for the outermost surfaces of the pair of positive and negative electrodes of the light-emitting element 20 as the Au layer 5 of the region 10, a more reliable connection can be achieved.

[0176] The number of light-emitting elements 20 may be one or more. When there are more than one light-emitting elements 20, their arrangement is not particularly limited, and examples thereof include arranging them in a row in a first direction or arranging them in a matrix. When the light-emitting device 200 has a horizontally elongated light distribution pattern suitable for vehicle headlights, it is preferable to arrange them in a row in the first direction. For example, when the shape of the ceramic substrate 100 in a horizontal plan view is rectangular, it is preferable to arrange the multiple light-emitting elements 20 in a row along the first direction, with the direction in which the long side extends being the first direction, and it is more preferable to arrange the multiple light-emitting elements 20 in a row at equal intervals along the first direction.

[0177] The light emitting element 20 is disposed on an area 10 of the ceramic substrate 100. The area 10 is disposed inside the frame 41 and is bonded to the light emitting element 20. However, the area 10 includes not only the bonded portion with the light emitting element 20 but also the surrounding area.

[0178] The shape of the light-emitting element 20 in a planar view in the horizontal direction is not particularly limited, and various shapes can be used, such as a circle, an ellipse, a polygon such as a square or a hexagon, a polygon with rounded corners, or a shape combining these shapes. Among these, a square is preferable, and a rectangle is more preferable. This allows the light-emitting elements 20 to be arranged closely together in the first direction, with the distance between the side surfaces of adjacent light-emitting elements 20 kept constant. As a result, a light-emitting surface that is horizontally elongated and rectangular in shape in a planar view in the horizontal direction can be formed as a whole.

[0179] The length, width, and height dimensions of the light-emitting element 20 can be set arbitrarily. Among these, it is preferable to use a large light-emitting element 20 in order to realize a light-emitting device 200 with a higher output, and in a plan view in the horizontal direction of the light-emitting element 20, the length and width dimensions of the light-emitting element 20 are preferably 600 μm or more, and more preferably 1,000 μm or more. Furthermore, from the viewpoints of uniformity of light emission intensity, ease of mounting, etc., the length and width dimensions of the light-emitting element 20 are preferably 2,000 μm or less.

[0180] The light emitting elements 20 are arranged to be spaced apart from adjacent light emitting elements 20. In this case, the distance between the light emitting elements 20 may be, for example, in the range of 0.1 to 0.5 times the length of one side along the first direction of the light emitting elements 20. Specifically, when light emitting elements 20 having vertical and horizontal dimensions of approximately 1,000 μm and a substantially square shape in plan view are used, the distance between adjacent light emitting elements 20 may be in the range of 100 μm to 500 μm.

[0181] (Joint member 60) The light-emitting element 20 is typically mounted on the ceramic substrate 100 via a bonding member 60. Examples of the bonding member 60 include Sn-Bi, Sn-Cu, Sn-Ag, and Au-Sn solders; eutectic alloys such as alloys primarily composed of Au and Sn, alloys primarily composed of Au and Si, and alloys primarily composed of Au and Ge; conductive pastes of Ag, Au, Pd, and the like; bumps; anisotropic conductive materials such as anisotropic conductive films (ACFs) and anisotropic conductive pastes (ACPs); brazing filler metals made of low-melting-point metals; and conductive adhesives and conductive composite adhesives combining these materials. These materials may be used alone or in combination. Among these, it is preferable that the light-emitting element 20 be mounted on the region 10 using a bonding member 60 containing Au. Because the outermost surface of the region 10 is the Au layer 5, using a bonding member containing Au can ensure a more reliable and stable connection over a long period of time.

[0182] (Reflective member 40) The reflective member 40 is a member having optical reflectivity. The reflective member 40 is disposed on the upper surface of the ceramic substrate 100, and is in contact with the Au layer 5 and the seed layer 2. The reflective member 40 is preferably disposed so as to further cover the side surfaces of the light-emitting element 20. In the light-emitting device 200, for example, the reflective member 40 is also disposed between the lower surface of the light-emitting element 20 and the upper surface of the ceramic substrate 100. The reflective member 40 is disposed on the upper surface of the ceramic substrate 100, and is in contact with the Au layer 5 and the seed layer 2, thereby making it possible to prevent the reflective member from lifting (peeling off).

[0183] The reflective member 40 preferably has a high reflectance to effectively utilize the light from the light emitting element 20. The reflective member 40 is preferably white. The reflectance of the reflective member 40 is preferably, for example, 90% or more, and more preferably 94% or more, at the wavelength of the light emitted by the light emitting element 20.

[0184] The reflective member 40 can be formed using, for example, a resin material. Examples of the resin material that can be used include thermoplastic resins such as acrylic resin, polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalate resin, polyethylene naphthalate resin, and polyester resin, and thermosetting resins such as epoxy resin and silicone resin.

[0185] Furthermore, it is preferable that the reflective member 40 contains a filler such as a light-reflecting substance in the resin material. Examples of the light-reflecting substance that can be used include known materials such as titanium oxide, silicon oxide, zirconium oxide, aluminum oxide, zinc oxide, potassium titanate, aluminum nitride, boron nitride, and mullite. The content of the light-reflecting substance can be adjusted appropriately depending on the characteristics of the light-emitting device 200 to be obtained, as it can change the amount of light reflection and transmission of the reflective member 40. However, the content of the light-reflecting substance is preferably 30% by mass or more of the total mass of the reflective member 40.

[0186] (Translucent member 30) The light-transmitting member 30 is preferably disposed on the light extraction surface side of the light-emitting element 20 and bonded to the light extraction surface of the light-emitting element 20 .

[0187] The light-transmitting member 30 has an upper surface and a lower surface, and light emitted from the light-emitting element 20 enters the lower surface of the light-transmitting member 30 and is emitted to the outside from the upper surface of the light-transmitting member 30, with the upper surface of the light-transmitting member 30 serving as a light extraction surface. The light-transmitting member 30 is preferably a member that transmits 60% or more of the light emitted from the light-emitting element 20.

[0188] The lower surface of the light-transmitting member 30 preferably covers the entire upper surface of the light-emitting element 20 in order to efficiently extract the light emitted from the light-emitting element 20. That is, in a plan view in the horizontal direction, the edge of the upper surface of the light-emitting element 20 is preferably covered so as to be included within the edge of the lower surface of the light-transmitting member 30. Furthermore, the area of ​​the upper surface of the light-transmitting member 30 is preferably smaller than the sum of the areas of the upper surfaces of the plurality of light-emitting elements 20 included in the light-emitting device 200. This allows the light emitted from the light-emitting element 20, which has entered from the lower surface of the light-transmitting member 30, to be emitted from the upper surface of the light-transmitting member 30 (i.e., the light-emitting surface of the light-emitting device 200), which has a smaller area. That is, the light-emitting device 200 has high brightness because the light emitted from the light-emitting element 20 is narrowed by the light-transmitting member 30, and can illuminate a greater distance.

[0189] The light-transmitting member 30 may cover the plurality of light-emitting elements 20 individually, or may cover the plurality of light-emitting elements 20 collectively. It is preferable that the outer peripheral side surface of the light-transmitting member 30 is covered with the reflecting member 40.

[0190] The thickness of the light-transmitting member 30 is not particularly limited, but is preferably 50 μm or more and 300 μm or less.

[0191] When one light-emitting device 200 includes multiple light-transmissive members 30, it is preferable that the upper surfaces of the multiple light-transmissive members 30 are flush or approximately flush. This more reliably prevents interference between light emitted from the side surfaces of the light-transmissive members 30. On the other hand, regardless of the number of light-transmissive members 30, the upper surfaces of the light-transmissive members 30 may have various shapes, such as an uneven surface, a curved surface, or a lens-like shape. It is preferable that the lower surface of the light-transmissive member 30 is a surface parallel to the light extraction surface of the light-emitting element 20.

[0192] The light-transmissive member 30 can be formed, for example, from a light-diffusing material or a material containing a phosphor capable of wavelength-converting at least a part of the light incident from the light-emitting element 20. Examples of the light-transmissive member 30 containing a phosphor include a sintered body of a phosphor; a material in which phosphor powder is contained in a resin, glass, or other inorganic substance. The sintered body of a phosphor may be formed by sintering only the phosphor, or may be formed by sintering a mixture of a phosphor and a sintering aid. When sintering a mixture of a phosphor and a sintering aid, it is preferable to use an inorganic material such as silicon oxide, aluminum oxide, or titanium oxide as the sintering aid. Thereby, even if the light-emitting element 20 has a high output, discoloration or deformation of the sintering aid due to light or heat can be suppressed. The higher the light transmittance of the light-transmissive member 30, the easier it is to reflect light at the interface with the reflecting member 40, so that the luminance can be improved.

[0193] As the phosphor contained in the light-transmissive member 30, a phosphor that can be excited by the light emitted from the light-emitting element 20 is used. For example, one of the following specific examples can be used alone, or two or more of them 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 yttrium aluminum garnet-based phosphors activated with cerium (e.g., Y3(Al,Ga)5O 12 :Ce), lutetium aluminum garnet-based phosphors activated with cerium (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(However, 0 < z ≤ 2, and M is a lanthanide element excluding Li, Mg, Ca, Y, and 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. can be mentioned. 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 light-transmissive member 30. When such a phosphor is contained in the light-transmissive member 30, it is preferable that the concentration of the phosphor is about 5% or more and 50% or less.

[0194] The joining of the light-transmissive member 30 and the light extraction surface of the light-emitting element 20 can be joined, for example, via a light guide member 61. Also, for the joining of the light-transmissive member 30 and the light-emitting element 20, direct joining by pressure bonding, sintering, surface activation bonding, atomic diffusion bonding, or hydroxyl group bonding may be used without using the light guide member 61.

[0195] The light-transmissive member 30 is usually disposed on the upper surface of the light-emitting element 20, but depending on its form, it may cover a part on the region 10 and / or a part on the pad portion 11.

[0196] (Frame body 41) The frame body 41 is disposed surrounding the light-emitting element 20 on the ceramic substrate 100. In a plan view in the horizontal direction, it is preferable that the outer edge of the frame body 41 includes the boundary between the region 10 and the pad portion 11. Thereby, the frame body 41 covers the step between the region 10 and the pad portion 11, the contact area with the frame body 41 becomes large, and the anchor effect due to the step can be exerted.

[0197] The frame 41 is provided at a distance from the outer edge of the upper surface of the ceramic substrate 100. This prevents the frame 41 and the reflective member 40 from being positioned on the singulation line when the assembly of light emitting devices 200 is singulated into individual light emitting devices 200 in the manufacturing process of the light emitting device 200. In other words, the resin member is not cut during singulation, and therefore deformation of the resin member due to stress during cutting and peeling from the ceramic substrate 100 can be suppressed.

[0198] The frame 41 is made of an insulating material to cover the region 10 and a portion of the pad portion 11. The frame 41 can be made of, for example, an insulating resin material. Examples of insulating resin materials include silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, acrylic resin, and hybrid resin containing at least one of these resins. These may be used alone or in combination of two or more.

[0199] The frame 41 can be made of an insulating resin material containing a filler such as a light-reflecting material. The light-reflecting material can be the same as the light-reflecting material in the reflecting member 40.

[0200] Furthermore, when frame 41 is disposed so as to contact region 10, region 10 preferably has grooves or holes 12 on the surface of the region that contacts frame 41. Ceramic plate 1 is preferably exposed at the bottom of grooves or holes 12. This improves adhesion between frame 41 and ceramic substrate 100, resulting in a light emitting device 200 with improved reliability.

[0201] (Other parts) The light emitting device 200 may be equipped with other elements, electronic components, etc., such as a protective element 42. These other elements and electronic components are preferably embedded in the reflective member 40.

[0202] The light emitting device 200 may also have a recognition mark 14 on its upper surface. The recognition mark 14 is provided between one side of the outer edge of the substantially rectangular ceramic substrate 100 to which the region 10 and the pad portion 11 do not extend and the outer edge of the frame 41. The recognition mark 14 can be used for, for example, recognizing the position of the light emitting surface of the light emitting device 200 when secondary mounting the light emitting device 200, or for recognizing the position when forming the frame 41 in the manufacturing process. The recognition mark 14 can be formed using, for example, the same metal material as the pad portion 11. Using the same material for the recognition mark 14, the surface of the pad portion 11, and the recognition mark 14 can suppress metal corrosion due to the potential difference between the different metal materials.

[0203] [Method for manufacturing a light-emitting device] A manufacturing method of the light emitting device according to the embodiment includes preparing a ceramic substrate 100 according to the embodiment, arranging a light emitting element 20 on the ceramic substrate 100, and arranging a reflective member 40 on the upper surface of the ceramic substrate 100, wherein the reflective member 40 is arranged so as to contact the Au layer 5 and seed layer 2 of the ceramic substrate 100.

[0204] FIG. 14 is a flowchart showing an example of a method for manufacturing a light emitting device according to this embodiment.

[0205] (S41) Preparing a ceramic substrate In preparing the ceramic substrate 100 S41, the ceramic substrate 100 according to the embodiment is prepared.

[0206] The ceramic substrate 100 may have multiple areas for arranging the light-emitting elements 20, and may be sized to be separated into individual light-emitting devices 200 after the reflective member 40 is arranged, or may have dimensions for each light-emitting device 200.

[0207] (S42) Arranging the light emitting element In disposing the light emitting element S42, the light emitting element 20 is disposed on the ceramic substrate 100. In disposing the light emitting element S42, it is preferable to connect the electrodes of the light emitting element 20 to the upper surface of the region 10 using a bonding member 60. It is preferable that the light emitting element 20 is disposed in a state in which the light-transmitting member 30 is previously connected to the light emitting element 20. When bonding the light-transmitting member 30 to the light emitting element 20, a light-transmitting bonding material is preferably used.

[0208] (S43) Arranging a reflective member In disposing the reflective member S43, the reflective member 40 is disposed on the upper surface of the ceramic substrate 100. At this time, the reflective member 40 is disposed so as to be in contact with the Au layer 5 and the seed layer 2 of the ceramic substrate 100. This makes it possible to prevent the reflective member from lifting (peeling off). Furthermore, in disposing the reflective member S43, it is preferable to dispose the reflective member 40 so as to cover the side surface of the light-emitting element 20. The reflective member 40 is disposed on the ceramic substrate 100 so as to surround the light-emitting element 20 and expose the upper surface of the light-transmitting member 30 disposed on the light extraction surface of the light-emitting element 20. It is preferable that the reflective member 40 is disposed so as to be rectangular in plan view.

[0209] In the manufacturing method of the light emitting device according to the embodiment, after arranging the reflective member (S43), a singulation process is performed as needed. Each unit of the light emitting device 200 is preset based on the number of light emitting elements 20 used. Therefore, when a plurality of light emitting devices 200 are manufactured together, a singulation process is performed. When the singulation process is performed, the light emitting devices 200 are produced by cutting into a grid pattern. Examples of cutting methods include methods using a disk-shaped rotary blade, an ultrasonic cutter, a laser beam emitting blade, etc. [Example]

[0210] The present invention will be specifically explained below by way of examples, but the present invention is not limited to these examples in any way.

[0211] Example 1 The ceramic substrate 100 was manufactured based on the flowchart of the fourth embodiment shown in Figure 11, and the top surface and cross section in the thickness direction of the intermediate body formed after performing step S34 of disposing the Cu layer were observed using a scanning electron microscope (SEM) under conditions of BED-C, acceleration voltage: 5.0 KV, probe current mode: Std.-PC50.0, and high vacuum.

[0212] The cross section in the thickness direction was exposed by cutting the intermediate body in the thickness direction (Z-axis direction) using focused ion beam processing (FIB).

[0213] Fig. 15A is an SEM image of a plan view in the horizontal direction of an intermediate ceramic substrate 100 obtained in step S34 of disposing a Cu layer in the method for manufacturing a ceramic substrate according to the fourth embodiment, observed from above at 50x magnification. Fig. 15B is an enlarged image of a cross section in the thickness direction of region XVB in Fig. 15A, which is an SEM image of a cross section in the thickness direction of an intermediate ceramic substrate 100 obtained in step S34 of disposing a Cu layer in the method for manufacturing a ceramic substrate according to the fourth embodiment, observed at 10,000x magnification.

[0214] The SEM image shows the ceramic plate 1, the first resist layer 50 arranged on the upper surface of the ceramic plate 1 and having an overhanging (reverse tapered) cross-sectional shape, the seed layer 2 arranged on the upper surface of the ceramic plate 1, the upper surface of the first resist layer 50, and the side surface of the first resist layer 50, the Cu layer arranged on the upper surface of the seed layer 2, and the space S2 between the upper surface of the ceramic plate 1 and the lower surface of the protrusion 50B. Although not clearly visible in the SEM image, a draft film of the second resist layer 51 is arranged so as to contact the upper surface of the seed layer 2 arranged on the upper surface of the first resist layer 50 and the side surface of the Cu layer 3.

[0215] As described above, the present invention has been described based on specific embodiments, but these are merely presented as examples, and the present invention is not limited to the above embodiments. The above embodiments can be embodied in various other forms, and various combinations, omissions, substitutions, additions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are also included in the inventions described in the claims and their equivalents.

[0216] In addition to the above-described embodiments, the following supplementary notes are also disclosed. (Appendix 1) A ceramic plate; a seed layer disposed on an upper surface of the ceramic plate; a Cu layer disposed on an upper surface of the seed layer; one or more intermediate layers disposed on an upper surface of the Cu layer and on side surfaces of the Cu layer; an Au layer disposed on the upper surface of the intermediate layer and on a side surface of the intermediate layer; and an upper surface of the seed layer and a lower surface of the intermediate layer are in contact with each other; the upper surface of the ceramic plate is not in contact with the lower surface of the Au layer, The ceramic substrate has an upper surface edge of the seed layer that is located outside the lower surface edge of the Cu layer in the horizontal direction. (Appendix 2) 2. The ceramic substrate according to claim 1, wherein an edge of the upper surface of the seed layer is located more inward than an edge of the lower surface of the Au layer in the horizontal direction. (Appendix 3) The ceramic substrate according to claim 1 or 2, wherein the side surface of the seed layer is exposed from the Au layer. (Appendix 4) the seed layer is disposed continuously from a lower surface of the Cu layer to a part of a side surface of the Cu layer, The ceramic substrate according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the intermediate layer is disposed so as to cover the seed layer disposed on a part of a side surface of the Cu layer. (Appendix 5) the intermediate layer includes a Ni layer and a Pd layer, the Ni layer is disposed on an upper surface of the Cu layer and on a side surface of the Cu layer; the Pd layer is disposed on an upper surface of the Ni layer and on a side surface of the Ni layer; The ceramic substrate according to any one of Supplementary Note 1 to Supplementary Note 4, wherein the Au layer is disposed on the upper surface of the Pd layer and on the side surfaces of the Pd layer. (Appendix 6) The ceramic substrate according to any one of appendices 1 to 5, wherein the seed layer is one or more selected from the group consisting of a Ti layer, a Cu layer, an Au layer, a Ru layer, a TiNi layer, a TiW layer, a CuNi layer, and a NiCr layer. (Appendix 7) The ceramic substrate according to any one of Supplementary Notes 1 to 6, wherein the seed layer has an average thickness of 0.1 μm or more and 2.0 μm or less. (Appendix 8) A ceramic substrate according to any one of claims 1 to 7, wherein in the horizontal direction, the edge of the upper surface of the seed layer is positioned 1.0 μm to 5.0 μm inward from the edge of the lower surface of the Au layer. (Appendix 9) The ceramic substrate according to any one of Supplementary Note 1 to Supplementary Note 8, further comprising a pad portion electrically connected to the Au layer. (Appendix 10) The pad portion includes the ceramic plate and the seed layer disposed on an upper surface of the ceramic plate; the intermediate layer disposed on top of the seed layer; and the Au layer disposed on an upper surface of the intermediate layer. (Appendix 11) The pad portion includes the ceramic plate and the seed layer disposed on an upper surface of the ceramic plate; and an Al layer disposed on an upper surface of the seed layer. (Appendix 12) A ceramic substrate according to any one of Supplementary Note 1 to Supplementary Note 11; and a light-emitting element disposed on the ceramic substrate. (Appendix 13) the light emitting device includes a reflecting member disposed on an upper surface of the ceramic substrate; 13. The light emitting device according to claim 12, wherein the reflective member is in contact with the Au layer and the seed layer. (Appendix 14) providing a first resist layer on an upper surface of a ceramic plate, and exposing and developing the first resist layer into a predetermined shape; disposing a seed layer on the upper surface of the ceramic plate exposed from the first resist layer after exposure and development, on the side surface of the first resist layer, and on the upper surface of the first resist layer; providing a second resist layer so as to cover at least a portion of an upper surface of the seed layer, and exposing and developing the second resist layer to a predetermined shape so that at least a portion of an upper surface of the seed layer disposed on the upper surface of the ceramic plate is exposed; disposing a Cu layer by electrolytic plating on the upper surface of the seed layer that has been exposed and developed and is now exposed from the second resist layer; removing a portion of the seed layer, the first resist layer, and the second resist layer; disposing one or more intermediate layers on an upper surface of the Cu layer and on side surfaces of the Cu layer; disposing an Au layer on an upper surface of the intermediate layer and on a side surface of the intermediate layer; The method for manufacturing a ceramic substrate includes the steps of: (Appendix 15) In exposing and developing the first resist layer into a predetermined shape, a length of a lower surface of the first resist layer in a cross section in a thickness direction of the ceramic plate is shorter than a length of an upper surface of the first resist layer; A method for manufacturing a ceramic substrate as described in Appendix 14, wherein, in placing the seed layer, the seed layer is placed so as to continuously cover the side surface of the first resist layer and the upper surface of the ceramic plate exposed from the first resist layer. (Appendix 16) In exposing and developing the first resist layer into a predetermined shape, the first resist layer is formed so that the cross-sectional shape of the first resist layer has an overhang shape; The method for manufacturing a ceramic substrate according to claim 15, wherein the second resist layer is a sheet-like resist in exposing and developing the second resist layer into a predetermined shape. (Appendix 17) A method for manufacturing a ceramic substrate according to any one of Appendix 14 to Appendix 16, wherein the second resist layer is exposed and developed into a predetermined shape so that at least a portion of the upper surface of the seed layer disposed on the upper surface of the ceramic plate is exposed from the second resist layer, without exposing the side surfaces of the first resist layer and the seed layer disposed on the upper surface of the first resist layer. (Appendix 18) The method for manufacturing a ceramic substrate according to any one of Supplementary Note 14 to Supplementary Note 17, wherein in disposing the seed layer, the seed layer has a thickness of 1.0 μm or more and 2.0 μm or less. (Appendix 19) A method for manufacturing a ceramic substrate according to any one of appendices 14 to 18, wherein the intermediate layer is arranged so as to cover the upper surface of the seed layer arranged on the upper surface of the ceramic plate. (Appendix 20) The disposing of the intermediate layer includes disposing a Ni layer on an upper surface of the Cu layer and on a side surface of the Cu layer, and disposing a Pd layer on an upper surface of the Ni layer and on a side surface of the Ni layer, The method for manufacturing a ceramic substrate according to any one of Supplementary Note 14 to Supplementary Note 19, wherein in disposing the Au layer, the Au layer is disposed on the top surface of the Pd layer and on the side surfaces of the Pd layer. (Appendix 21) In exposing and developing the second resist layer, the second resist layer is exposed and developed so as to expose the seed layer disposed on the side surface of the first resist layer; A method for manufacturing a ceramic substrate according to any one of appendices 14 to 20, wherein in disposing the Cu layer, the Cu layer is disposed on the seed layer disposed on the side surface of the first resist layer by electroplating. (Appendix 22) The method for manufacturing a ceramic substrate according to any one of Appendix 14 to Appendix 21, wherein the intermediate layer is arranged so as to cover the seed layer arranged on the side surface of the Cu layer and the upper surface of the Cu layer. (Appendix 23) A method for manufacturing a ceramic substrate as described in Appendix 14, wherein, after removing the first resist layer and the second resist layer, the edge of the upper surface of the seed layer is positioned horizontally outward from the edge of the lower surface of the Cu layer. (Appendix 24) The method for manufacturing a ceramic substrate according to any one of Supplementary Note 14 to Supplementary Note 23, wherein the first resist layer and the second resist layer are made of a negative photoresist. (Appendix 25) Preparing a ceramic substrate according to any one of Supplementary Note 1 to Supplementary Note 11; disposing a light emitting element on the ceramic substrate; and disposing a reflecting member on the upper surface of the ceramic substrate; In the method for manufacturing a light emitting device, the reflective member is disposed so as to be in contact with the Au layer and the seed layer of the ceramic substrate. [Explanation of symbols]

[0217] 1. Ceramic plate 2. Seed layer 2a Edge of the top surface of the seed layer 3. Cu layer 3b Edge of the lower surface of the Cu layer 4. Middle class 4b Edge of the lower surface of the middle layer 4-1 The first middle class 4-2 The second middle class 5 Au layer 5b Edge of the lower surface of the Au layer 10 areas 11 Pad section 11A Pad section 11B Pad section 13 Heat radiation part 12 Grooves or holes 14 Recognition Mark 20 Light-emitting element 30 Translucent material 40 Reflective material 50 First resist layer 51 Second resist layer 41 Frame 42 Protection element 60 Joint material L1 Length of the bottom surface of the first resist layer L2 Length of the top surface of the first resist layer S1 space S2 space 100 Ceramic substrate 200 Light-emitting device

Claims

1. A ceramic plate; a seed layer disposed on an upper surface of the ceramic plate; a Cu layer disposed on an upper surface of the seed layer; one or more intermediate layers disposed on an upper surface and a side surface of the Cu layer; an Au layer disposed on a top surface of the intermediate layer and on a side surface of the intermediate layer; and an upper surface of the seed layer and a lower surface of the intermediate layer are in contact with each other; the upper surface of the ceramic plate is not in contact with the lower surface of the Au layer, A ceramic substrate, wherein an edge of the upper surface of the seed layer is located outside an edge of the lower surface of the Cu layer in the horizontal direction.

2. The ceramic substrate according to claim 1 , wherein an edge of the upper surface of the seed layer is located more inward than an edge of the lower surface of the Au layer in the horizontal direction.

3. The ceramic substrate according to claim 1 , wherein a side surface of the seed layer is exposed from the Au layer.

4. the seed layer is disposed continuously from a lower surface of the Cu layer to a part of a side surface of the Cu layer, The ceramic substrate according to claim 1 , wherein the intermediate layer is disposed so as to cover the seed layer disposed on a part of a side surface of the Cu layer.

5. the intermediate layer includes a Ni layer and a Pd layer, the Ni layer is disposed on an upper surface of the Cu layer and on a side surface of the Cu layer; the Pd layer is disposed on an upper surface of the Ni layer and on a side surface of the Ni layer; The ceramic substrate according to claim 1 , wherein the Au layer is disposed on an upper surface of the Pd layer and on a side surface of the Pd layer.

6. 2. The ceramic substrate according to claim 1, wherein the seed layer is at least one selected from the group consisting of a Ti layer, a Cu layer, an Au layer, a Ru layer, a TiNi layer, a TiW layer, a CuNi layer, and a NiCr layer.

7. The ceramic substrate according to claim 1 , wherein the seed layer has an average thickness of 0.1 μm or more and 2.0 μm or less.

8. 2. The ceramic substrate according to claim 1, wherein an edge of the upper surface of the seed layer is positioned 1.0 μm to 5.0 μm inward from an edge of the lower surface of the Au layer in the horizontal direction.

9. The ceramic substrate according to claim 1 , further comprising a pad portion electrically connected to the Au layer.

10. The pad portion includes the ceramic plate and the seed layer disposed on an upper surface of the ceramic plate; the intermediate layer disposed on top of the seed layer; The ceramic substrate according to claim 9 , further comprising: the Au layer disposed on an upper surface of the intermediate layer.

11. The pad portion includes the ceramic plate and the seed layer disposed on an upper surface of the ceramic plate; The ceramic substrate according to claim 9 , further comprising: an Al layer disposed on an upper surface of the seed layer.

12. The ceramic substrate according to claim 1; a light-emitting element disposed on the ceramic substrate.

13. the light emitting device includes a reflecting member disposed on an upper surface of the ceramic substrate; The light emitting device according to claim 12 , wherein the reflective member is in contact with the Au layer and the seed layer.

14. providing a first resist layer on an upper surface of a ceramic plate, and exposing and developing the first resist layer into a predetermined shape; disposing a seed layer on the upper surface of the ceramic plate exposed from the first resist layer after exposure and development, on the side surface of the first resist layer, and on the upper surface of the first resist layer; providing a second resist layer so as to cover at least a portion of an upper surface of the seed layer, and exposing and developing the second resist layer to a predetermined shape so that at least a portion of an upper surface of the seed layer disposed on the upper surface of the ceramic plate is exposed; disposing a Cu layer by electrolytic plating on the upper surface of the seed layer that has been exposed and developed and is now exposed from the second resist layer; removing a portion of the seed layer, the first resist layer, and the second resist layer; disposing one or more intermediate layers on an upper surface of the Cu layer and on side surfaces of the Cu layer; disposing an Au layer on an upper surface of the intermediate layer and on a side surface of the intermediate layer; A method for manufacturing a ceramic substrate, comprising:

15. In exposing and developing the first resist layer into a predetermined shape, a length of a lower surface of the first resist layer in a cross section in a thickness direction of the ceramic plate is shorter than a length of an upper surface of the first resist layer; 15. The method for manufacturing a ceramic substrate according to claim 14, wherein the seed layer is disposed so as to continuously cover the side surface of the first resist layer and the upper surface of the ceramic plate exposed from the first resist layer.

16. In exposing and developing the first resist layer into a predetermined shape, the first resist layer is formed so that the cross-sectional shape of the first resist layer has an overhang shape; 16. The method for manufacturing a ceramic substrate according to claim 15, wherein, in exposing and developing the second resist layer into a predetermined shape, the second resist layer is a sheet-like resist.

17. 15. The method for manufacturing a ceramic substrate according to claim 14, wherein when the second resist layer is exposed and developed into a predetermined shape, the second resist layer is exposed and developed so that at least a portion of the upper surface of the seed layer arranged on the upper surface of the ceramic plate is exposed from the second resist layer without exposing the side surfaces of the first resist layer and the seed layer arranged on the upper surface of the first resist layer.

18. The method for manufacturing a ceramic substrate according to claim 14 , wherein in disposing the seed layer, the seed layer has a thickness of 1.0 μm or more and 2.0 μm or less.

19. The method for manufacturing a ceramic substrate according to claim 14 , wherein in disposing the intermediate layer, the intermediate layer is disposed so as to cover an upper surface of the seed layer disposed on the upper surface of the ceramic plate.

20. the disposing of the intermediate layer includes disposing a Ni layer on an upper surface of the Cu layer and on a side surface of the Cu layer, and disposing a Pd layer on an upper surface of the Ni layer and on a side surface of the Ni layer; The method for manufacturing a ceramic substrate according to claim 14 , wherein the Au layer is disposed on an upper surface of the Pd layer and on side surfaces of the Pd layer.

21. In exposing and developing the second resist layer, the second resist layer is exposed and developed so as to expose the seed layer disposed on the side surface of the first resist layer; The method for manufacturing a ceramic substrate according to claim 14 , wherein in disposing the Cu layer, the Cu layer is disposed on the seed layer disposed on the side surface of the first resist layer by electrolytic plating.

22. The method for manufacturing a ceramic substrate according to claim 14, wherein the step of disposing the intermediate layer comprises disposing the intermediate layer so as to cover the seed layer disposed on the side surface of the Cu layer and an upper surface of the Cu layer.

23. 15. The method for manufacturing a ceramic substrate according to claim 14, wherein after removing the first resist layer and the second resist layer, the edge of the upper surface of the seed layer is positioned horizontally outward from the edge of the lower surface of the Cu layer.

24. The method for manufacturing a ceramic substrate according to claim 14, wherein the first resist layer and the second resist layer are made of a negative photoresist.

25. Preparing the ceramic substrate according to any one of claims 1 to 11; disposing a light emitting element on the ceramic substrate; and disposing a reflecting member on the upper surface of the ceramic substrate; In the step of disposing the reflective member, the reflective member is disposed so as to be in contact with the Au layer and the seed layer of the ceramic substrate.

Images