Wiring board and method for manufacturing the same

Abstract

To provide a method for manufacturing a wiring board having excellent electrical conductivity that can easily form various electrode patterns, and a wiring board that has fine electrode patterns and has excellent electrical conductivity.SOLUTION: A method for manufacturing a wiring board includes preparing a ceramic substrate having a ceramic plate having a first recess portion on a first surface, a second recess portion on a second surface opposite to the first surface, and a through-hole connecting the first recess portion and the second recess portion and a metal member disposed in continuity with the first recess portion, the second recess portion, and the through-hole, arranging a protective film on at least a part of the metal member of the ceramic substrate, performing blasting processing on portions of the metal member other than the part of the metal member on which the protective film is disposed and at least a part of the first surface of the ceramic plate, arranging a covering member in the recess portion from which the other portions of the metal member and at least the part of the first surface of the ceramic plate have been removed by the blasting processing, and removing the protective film.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a wiring board and a method for manufacturing the same.

Background Art

[0002] Ceramic substrates are widely used as wiring boards for electronic components. For example, without polishing a ceramic substrate, wet etching or dry etching is performed on the surface of the ceramic substrate having vias to form an etching surface, and vias protruding from the etching surface are formed. Then, an organic insulating layer is disposed on the etching surface and polished to manufacture a ceramic substrate having vias on the surface of the organic insulating layer (see Patent Document 1).

[0003] Also, a method for processing a substrate is known in which a mask layer is formed on the surface of a substrate made of ceramics or the like, the mask layer on the substrate surface is patterned, the substrate surface exposed without being covered by the mask layer is processed, and a plurality of recesses having different depths are formed on the substrate surface by wet etching (see Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a method for manufacturing a wiring board that can easily form various electrode patterns and has excellent conductivity, and a wiring board having a fine electrode pattern and excellent conductivity.

Means for Solving the Problems

[0006] A method for manufacturing a wiring board according to an embodiment of the present disclosure includes preparing a ceramic substrate including a ceramic plate having a first recess disposed on a first surface, a second recess disposed on a second surface opposite to the first surface, and a through hole connecting the first recess and the second recess, and a metal member continuously disposed in the first recess, the second recess, and the through hole; disposing a protective film on at least a part of the metal member of the ceramic substrate; blasting at least a part of the other part of the metal member other than the part where the protective film is disposed and at least a part of the first surface of the ceramic plate; disposing a covering member in a recess formed by removing at least a part of the other part of the metal member and at least a part of the first surface of the ceramic plate by the blasting; and removing the protective film.

[0007] A wiring board according to an embodiment of the present disclosure includes a ceramic substrate including a ceramic plate having a first recess disposed on a first surface, a second recess disposed on a second surface opposite to the first surface, and a through hole connecting the first recess and the second recess, and a metal member continuously disposed in the first recess, the second recess, and the through hole and having a convex portion whose upper surface on the first surface side is convex with respect to the first surface, and a covering member disposed so as to be in contact with at least a part of the other part of the upper surface of the metal member other than the upper surface of the convex portion and at least a part of the first surface of the ceramic plate, wherein a surface roughness Ra of at least a part of the other part of the upper surface of the metal member and at least a part of the first surface of the ceramic plate is 350 nm or more.

Advantages of the Invention

[0008] According to an embodiment of the present disclosure, various electrode patterns can be easily formed, and a method for manufacturing a wiring board excellent in conductivity and a wiring board having a fine electrode pattern and excellent in conductivity can be provided.

Brief Description of the Drawings

[0009]

Figure 1A

Figure 1B

Figure 1C

Figure 2

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Figure 3B

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Figure 4E

Figure 5A

Figure 5B

Figure 5C

Figure 5D

Figure 5E

Figure 5F

Figure 5G

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 8A

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Figure 9A

Figure 9B

Figure 9C

Mode for Carrying Out the Invention

[0010] Hereinafter, a substrate according to an embodiment of the present invention (hereinafter sometimes referred to as "wiring substrate according to the embodiment") and a method for manufacturing the wiring substrate (hereinafter sometimes referred to as "method for manufacturing the wiring substrate according to the embodiment") will be described with reference to the drawings. In the following description, terms indicating specific directions and positions (for example, "up", "down", and other terms including these terms) are used as necessary. However, the use of these terms is for facilitating the understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meanings of those terms. Also, parts or members denoted by the same reference numerals in a plurality of drawings indicate the same or equivalent parts or members.

[0011] Further, the embodiments shown below exemplify a wiring substrate and a method for manufacturing the wiring substrate for embodying the technical idea of the present invention, and do not limit the present invention to the following. Also, dimensions, materials, shapes, relative arrangements, etc. of parts or members described below are not intended to limit the scope of the present invention only to those, but are intended to be exemplified unless specifically described. Also, the content described in one embodiment is applicable to other embodiments and modified examples. Also, dimensions and positional relationships of parts or members shown in the drawings may be exaggerated for clarity of explanation. Further, in order to avoid excessive complexity of the drawings, a schematic diagram omitting the illustration of some parts or members may be used, or an end view showing only the cut surface as a cross-sectional view may be used. Also, "arrange" includes not only the case of direct contact but also the case of indirect arrangement, for example, via other members.

[0012] In the wiring substrate according to the embodiment and the method for manufacturing the wiring substrate, the first surface having the covering member 4 of the wiring substrate 200 is defined as the "surface" used for electrically connecting to the electrode of the light-emitting element, and the second surface on the opposite side of the first surface of the wiring substrate 200 is defined as the "back surface" used for electrically connecting to the electrode of the mounting substrate. In each drawing related to the wiring substrate according to the embodiment and the method for manufacturing the wiring substrate, unless otherwise specified, the first surface of the wiring substrate 200 is shown on the upper side of the drawing, and the second surface of the wiring substrate 200 is shown on the lower side of the drawing.

[0013] In the wiring board and the method for manufacturing the wiring board according to the embodiment, the "ceramic plate 1" refers to a member composed only of ceramics without the metal member 2.

[0014] In the wiring board and the method for manufacturing the wiring board according to the embodiment, the "ceramic substrate 100" refers to a member in a state where the ceramic plate 1 is provided with the metal member 2.

[0015] In the method for manufacturing the wiring board according to the embodiment, the "wiring board 200" refers to the final form including the ceramic plate 1, the metal member 2, and the covering member 4.

[0016] 〔Wiring Board〕 The wiring board according to the embodiment includes a ceramic plate having a first recess disposed on a first surface, a second recess disposed on a second surface opposite to the first surface, and a through hole connecting the first recess and the second recess, and a metal member continuously disposed in the first recess, the second recess, and the through hole, the upper surface on the first surface side of which has a convex portion convex with respect to the first surface. The wiring board further includes a covering member disposed so as to contact at least a part of the other part of the upper surface of the metal member and the first surface of the ceramic plate other than the upper surface of the convex portion, and further includes other members as required. The surface roughness Ra of at least a part of the other part of the upper surface of the metal member and the first surface of the ceramic plate is 350 nm or more.

[0017] The wiring board according to the embodiment is preferably manufactured by the method for manufacturing the wiring board according to the embodiment.

[0018] FIG. 1A is a plan view showing an example of the first surface of the wiring board according to the embodiment. FIG. 1B is a cross-sectional view taken along line IB-IB of FIG. 1A. FIG. 1C is an explanatory view showing only the ceramic plate in FIG. 1B. FIG. 2 is an enlarged view of region II in FIG. 1B.

[0019] The wiring board 200 according to the embodiment has a ceramic substrate 100 and a covering member 4.

[0020] (Ceramic substrate) The ceramic substrate 100 has a ceramic plate 1 and a metal member 2.

[0021] <Ceramic plate> As shown in FIGS. 1B and 1C, the ceramic substrate 100 has a first recess 1a disposed on the first surface 1A of the ceramic plate 1, a second recess 1b disposed on the second surface 1B opposite to the first surface 1A of the ceramic plate 1, and a through hole 1c connecting the first recess and the second recess.

[0022] The material of the ceramic plate 1 is not particularly limited. For example, nitride-based ceramics such as silicon nitride, aluminum nitride, and boron nitride; oxide-based ceramics such as aluminum oxide, silicon oxide, calcium oxide, and magnesium oxide; silicon carbide; mullite; borosilicate glass, etc. may be mentioned. These may be used alone or in combination of two or more. Among these, as the ceramic, nitride-based ceramics are preferable from the viewpoint of thermal conductivity.

[0023] The ceramic plate 1 is a sintered ceramic plate.

[0024] The thickness of the ceramic plate 1 is not particularly limited, but is preferably 50 μm or more and 500 μm or less, and more preferably 80 μm or more and 400 μm or less.

[0025] The planar shape of the first recess 1a and the bottom surface shape of the second recess 1b are not particularly limited. For example, polygons such as triangles, quadrilaterals, pentagons, and hexagons, circles, ellipses, etc. may be mentioned. Also, a shape combining these shapes may be used. The bottom surface shape of the second recess 1b is preferably similar to or the same as the electrode on the mounting substrate side.

[0026] In the ceramic plate 1, the maximum diameter in the plan view direction of the first recess 1a on the first surface 1A of the ceramic plate 1 is not particularly limited and can be appropriately selected according to the electrodes of the light-emitting element. It is preferably 10 μm or more and 10 mm or less, and more preferably 50 μm or more and 5 mm or less.

[0027] In the ceramic plate 1, the area in the plan view direction of the first recess 1a on the first surface 1A of the ceramic plate 1 is not particularly limited and can be appropriately selected according to the electrodes of the light-emitting element. It is preferably 100 μm 2 or more and 100 mm 2 or less, and more preferably 2,500 μm 2 or more and 25 mm 2 or less. The area in the plan view direction of the first recess 1a of the ceramic plate 1 becomes the maximum area of the exposed surface of the metal member 2 on the first surface 1A.

[0028] In the ceramic plate 1, the maximum diameter in the plan view direction of the second recess 1b on the second surface 1B of the ceramic plate 1 is not particularly limited and can be appropriately selected according to the electrodes of the light-emitting element. It is preferably 30 μm or more and 10 mm or less, and more preferably 50 μm or more and 5 mm or less.

[0029] In the ceramic plate 1, the area in the plan view direction of the second recess 1b on the second surface 1B of the ceramic plate 1 is not particularly limited, but it is preferably 100 μm 2 or more and 100 mm 2 or less, and more preferably 2,500 μm 2 or more and 25 mm 2 or less. The area in the plan view direction of the second recess 1b of the ceramic plate 1 becomes the maximum area of the exposed surface of the metal member 2.

[0030] The first recess 1a is recessed from the first surface 1A of the ceramic plate 1, and in the cross-sectional view in the thickness direction of the ceramic plate 1, it refers to the region from the opening on the first surface 1A to the end of the through-hole c on the first surface 1A side. The number of the first recesses 1a in the ceramic substrate 100 is not particularly limited, but it is preferably plural.

[0031] The second recess 1b is recessed from the second surface 1B of the ceramic plate 1, and in a cross-sectional view in the thickness direction of the ceramic plate 1, it refers to the region from the opening in the second surface 1B to the end of the through-hole c on the second surface 1B side. The number of the second recesses 1b in the ceramic substrate 100 is not particularly limited, but it is preferably plural. Note that the number of the second recesses 1b in the ceramic substrate 100 is the same as the number of the first recesses 1a in the ceramic substrate 100.

[0032] The through-hole 1c is a region connecting the first recess 1a and the second recess 1b. That is, in a cross-sectional view in the thickness direction of the ceramic plate 1, it refers to the region from the end of the through-hole c on the first surface 1A side to the end of the through-hole c on the second surface 1B side. The number of the through-holes 1c in the ceramic substrate 100 is not particularly limited, but it is preferably plural. Note that the number of the through-holes 1c in the ceramic substrate 100 is the same as the number of the first recesses 1a and the number of the second recesses 1b in the ceramic substrate 100.

[0033] The average depth of the first recess 1a and the average depth of the second recess 1b are not particularly limited, but are preferably 1 / 10 or more and 2 / 5 or less, more preferably 1 / 5 or more and 1 / 4 or less, with respect to the thickness of the ceramic plate 1.

[0034] Note that the depth of the first recess 1a means the distance from the opening of the first recess 1a in the first surface 1A of the ceramic plate 1 to the end of the through-hole c on the first surface 1A side in a cross-sectional view in the thickness direction of the ceramic plate 1. Also, the average depth of the first recess 1a means the average value of arbitrarily selected three points for the depth of the first recess 1a. Further, the average depth of the first recess 1a satisfies [the thickness of the ceramic plate 1 - the average depth of the second recess 1b - the average length of the through-hole 1c].

[0035] The depth of the second recess 1b means the distance from the opening of the second recess 1b on the second surface 1B of the ceramic plate 1 to the end of the through-hole c on the second surface 1B side in a cross-sectional view in the thickness direction of the ceramic plate 1. The average depth of the second recess 1b means the average value of arbitrarily selected three points for the depth of the second recess 1b. The average depth of the second recess 1b satisfies [the thickness of the ceramic plate 1 - the average depth of the first recess 1a - the average length of the through-hole 1c].

[0036] The planar shape of the through-hole 1c is not particularly limited, and examples include polygons such as triangles, quadrilaterals, pentagons, hexagons, etc., circles, ellipses, etc. Also, a shape combining these shapes may be used. Among these, a circular shape is preferred.

[0037] In the ceramic plate 1, the maximum diameter in the planar view direction of the through-hole 1c is not particularly limited, but is preferably 20 μm or more and 500 μm or less, and more preferably 40 μm or more and 300 μm or less.

[0038] In the ceramic plate 1, the area in the planar view direction of the through-hole 1c is not particularly limited, but is preferably 400 μm 2 or more and 0.25 mm 2 or less, and more preferably 1,600 μm 2 or more and 0.09 mm 2 or less.

[0039] In the ceramic plate 1, the area or maximum diameter in the planar view direction of at least one of the first recess 1a and the second recess 1b may be the same as the area or maximum diameter of the through-hole 1c, may be larger than the area or maximum diameter of the through-hole 1c, or may be smaller than the area or maximum diameter of the through-hole 1c, but it is preferably larger than the area or maximum diameter of the through-hole 1c, and more preferably the area or maximum diameter of the first recess 1a is larger than the area or maximum diameter of the through-hole 1c. Thereby, the area or maximum diameter in the planar view direction of the metal member 2 disposed in the first recess 1a, that is, the area or maximum diameter of the exposed surface of the metal member 2 on the first surface 1A of the ceramic plate 1 becomes larger than the area or maximum diameter of the metal member 2 disposed in the through-hole 1c in the planar view direction.

[0040] The length of the through hole 1c is not particularly limited and can be appropriately selected according to the thickness of the ceramic plate 1, the depth of the first recess 1a, and the depth of the second recess 1b. The length of the through hole 1c means the distance from the bottom of the first recess 1a to the bottom of the second recess 1b in a cross-sectional view in the thickness direction of the ceramic plate 1. Further, the average length of the through hole 1c means the average value of arbitrarily selected three points with respect to the length of the through hole 1c. Further, the average length of the through hole 1c satisfies [the thickness of the ceramic plate 1 - the average depth of the first recess 1a - the average depth of the second recess 1b].

[0041] In the ceramic plate 1, when the shapes and areas of the first recess 1a, the second recess 1b, and the through hole 1c in the plan view direction are the same, the first recess 1a, the second recess 1b, and the through hole 1c in the plan view direction of the ceramic plate 1 have depths that are one-third each. In this case, in the ceramic plate 1, the first recess 1a, the second recess 1b, and the through hole 1c form a through hole in which they are integrated.

[0042] The surface roughness Ra of at least a part of the first surface 1A of the ceramic plate 1 is not particularly limited, but is preferably 350 nm or more, and more preferably 500 nm or more. The surface roughness Ra can be measured in accordance with JIS B 0601:2013 using a stylus-type surface roughness meter equipped with a diamond stylus having a tip curvature radius r of 2 μm (for example, Surfcorder SE3500 manufactured by Kosaka Laboratory Ltd.). Such "at least a part of the first surface 1A of the ceramic plate 1" having the surface roughness Ra is the region of the first surface 1A of the ceramic plate 1 that is in contact with the coating member 4. Making the surface roughness Ra of at least a part of the first surface 1A of the ceramic plate 1 350 nm or more can be achieved by forming at least a part of the first surface 1A of the ceramic plate 1 by a blasting process in the manufacture of the wiring board 200.

[0043] Although there is no particular limitation on the surface roughness Ra of at least a part of the other part of the first surface 1A of the ceramic plate 1, it is preferably 10 nm or more and 300 nm or less, and more preferably 30 nm or more and 200 nm or less. The "at least a part of the other part of the first surface 1A of the ceramic plate 1" having such a surface roughness Ra is a region of the first surface 1A of the ceramic plate 1 that is not in contact with the covering member 4, and preferably, it is a region of the first surface 1A of the ceramic plate 1 that is flush with the upper surface of the convex portion 2a of the metal member 2. Setting the surface roughness Ra of at least a part of the other part of the first surface 1A of the ceramic plate 1 to 10 nm or more and 300 nm or less can be achieved by disposing a protective film on at least a part of the other part of the first surface 1A of the ceramic plate 1 in the manufacture of the wiring substrate 200 so as not to be subjected to blasting treatment.

[0044] <metal member> As shown in FIGS. 1B and 1C, the metal member 2 is continuously disposed in the first recess 1a, the second recess 1b, and the through hole 1c, and has a convex portion 2a whose upper surface on the first surface 1A side is convex with respect to the first surface 1A.

[0045] The metal member 2 is not particularly limited as long as it is a member containing metal, but preferably contains metal, a metal compound, and an inorganic filler. Thereby, the linear expansion coefficients of the metal member 2 and the ceramic plate 1 can be made closer, and the peeling between the metal member 2 and the ceramic plate 1 can be reduced. The details of the components of the metal member 2 will be described in detail in [Manufacturing method of wiring substrate] described later.

[0046] Although there is no particular limitation on the shape, structure, and dimensions of the convex portion 2a of the metal member 2, it is preferable that the area of the upper surface of the convex portion 2a of the metal member 2 is smaller than the area of the lower surface of the convex portion 2a. The lower surface of the convex portion 2a refers to the lower surface of the metal member 2 disposed on the first recess 1a side when cut in a direction parallel to the plane of the ceramic plate 1 at the boundary between the first recess 1a and the through hole 1c.

[0047] In addition, in a cross-sectional view in the thickness direction of the wiring board 200, the center of gravity of the upper surface of the convex portion 2a and the center of gravity of the lower surface of the convex portion 2a may be at the same position or at different positions. In a cross-sectional view in the thickness direction of the wiring board 200, when the center of gravity of the upper surface of the convex portion 2a and the center of gravity of the lower surface of the convex portion 2a are at the same position, the shape of the convex portion 2a is symmetric with respect to the center line in the thickness direction of the wiring board 200. Further, in a cross-sectional view in the thickness direction of the wiring board 200, when the center of gravity of the upper surface of the convex portion 2a and the center of gravity of the lower surface of the convex portion 2a are at different positions, the shape of the convex portion 2a is asymmetric with respect to the center line in the thickness direction of the wiring board 200. FIG. 1B shows an example in which the shape of the metal member 2 is asymmetric.

[0048] Further, as shown in FIG. 2, the shape of the convex portion 2a of the metal member 2 is a shape in which the width continuously widens from the upper surface of the convex portion 2a toward the lower surface of the convex portion 2a in a cross-sectional view in the thickness direction of the wiring board 200, and in a cross-sectional view in the thickness direction of the wiring board 200, other portions 2r of the upper surface of the metal member 2 other than the upper surface of the convex portion 2a of the metal member 2 1、 2r2 is a curve. Other portions 2r of the upper surface of the metal member 2 other than the upper surface of the convex portion 2a of the metal member 2 1、 Since 2r2 is a curve, the wiring board 200 has high thermal conductivity and heat dissipation.

[0049] In a cross-sectional view in the thickness direction of the wiring board 200, other portions 2r of the upper surface of the metal member 2 other than the upper surface of the convex portion 2a of the metal member 2 1、 The roundness of 2r2 is not particularly limited, but it is preferably a shape corresponding to an arc with a radius of 2 μm or more and 110 μm or less. In a cross-sectional view in the thickness direction of the wiring board 200, the radius of roundness of the other portion 2r1 of the upper surface of the metal member 2 and the radius of roundness of the other portion 2r2 of the upper surface of the metal member 2 may be the same or different.

[0050] Other portions 2r of the upper surface of the metal member 2 other than the upper surface of the convex portion 2a of the metal member 2 1、 Making 2r2 a curve can be realized by forming the convex portion 2a of the metal member 2 by a blasting process in the manufacture of the wiring board 200.

[0051] Other parts 2b and 2r of the upper surface of the metal member 2, excluding the upper surface of the convex portion 2a of the metal member 2 1、 Although there is no particular limitation on the surface roughness Ra of 2r2, it is preferably 350 nm or more, and more preferably 500 nm or more. The "other parts 2b and 2r of the upper surface of the metal member 2" having such a surface roughness Ra 1、 "2r2" is the area of the upper surface of the metal member 2 in contact with the coating member 4. Other parts 2b and 2r of the upper surface of the metal member 2 1、 Setting the surface roughness Ra of 2r2 to 350 nm or more can be achieved by forming other parts 2b of the upper surface of the metal member 2 by blasting in the manufacture of the wiring board 200.

[0052] Although there is no particular limitation on the surface roughness Ra of the upper surface of the convex portion 2a of the metal member 2, it is preferably 10 nm or more and 300 nm or less, and more preferably 30 nm or more and 200 nm or less. The "upper surface of the convex portion 2a of the metal member 2" having such a surface roughness Ra

[0053] (Coating member) The coating member 4 is arranged to be in contact with other parts 2b and 2r of the upper surface of the metal member 2, excluding the upper surface of the convex portion 2a. 1、 2r2.

[0054] There is no particular limitation on the coating member, and it can be appropriately selected according to the purpose. However, it preferably includes a light-reflective member, and may further contain other components as necessary. The coating member preferably has a higher reflectance in visible light than the ceramic plate 1 in the ceramic substrate 100.

[0055] Examples of the light-reflective member include a resin or glass containing a reflective material.

[0056] Examples of the reflective material include titanium oxide, silicon oxide, aluminum oxide, zinc oxide, etc. These may be used alone or in combination of two or more.

[0057] Examples of the resin include thermoplastic resins such as acrylic resin, polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalate resin, polyethylene naphthalate resin or polyester resin, or thermosetting resins such as epoxy resin or silicone resin, etc. These may be used alone or in combination of two or more.

[0058] [Manufacturing method of wiring board] The manufacturing method of the wiring board according to the embodiment includes preparing a ceramic substrate having a first recess disposed on a first surface, a second recess disposed on a second surface opposite to the first surface, and a through hole connecting the first recess and the second recess, a metal member continuously disposed in the first recess, the second recess, and the through hole, disposing a protective film on at least a part of the metal member of the ceramic substrate, blasting at least a part of the other part of the metal member and at least a part of the first surface of the ceramic substrate other than the part of the metal member where the protective film is disposed, disposing a covering member in a recess where at least a part of the other part of the metal member and at least a part of the first surface of the ceramic substrate are removed by the blasting process, and removing the protective film. The manufacturing method of the wiring board according to the embodiment preferably further includes polishing or grinding the exposed surface of the covering member after disposing the covering member, and further includes other steps as required.

[0059] Conventionally, when attempting to form complex wiring patterns or wiring patterns with multiple shapes, the formation positions and sizes of the recesses in the ceramic substrate vary, and the formation time by laser processing varies according to the size of the recesses, which may require a significant amount of time to fabricate the wiring substrate. Also, when the recesses in the ceramic substrate are small, the filling of the conductive members may be insufficient. Furthermore, when the light-emitting element is changed or the positions of the electrodes of the light-emitting element are different, it may be necessary to prepare different wiring substrates.

[0060] In contrast, the manufacturing method of the wiring substrate according to the embodiment can easily form various wiring patterns according to the electrode positions and shapes of the electronic components. That is, by setting the formation position of the protective film to a location corresponding to the electrode position of the electronic component and performing a blasting process on the portions other than where the protective film is disposed, convex portions can be fabricated on the metal member. The convex portions correspond to the electrode positions of the electronic components. Even when the electrodes of the electronic components are small, the convex portions can be easily manufactured. Also, the positions of the convex portions can be changed without changing the ceramic substrate. Furthermore, convex portions having a part of the metal member and a part of the ceramic plate can be formed, thereby simplifying the mounting of the electronic components. Also, small light-emitting elements or different types of light-emitting elements can be used on the surface.

[0061] FIG. 3A is a flowchart showing an example of the manufacturing method of the wiring substrate according to the embodiment. FIG. 3B is a flowchart showing an example of preparing the ceramic substrate in the manufacturing method of the wiring substrate according to the embodiment.

[0062] As shown in FIG. 3A, the manufacturing method of the wiring substrate according to the embodiment includes preparing a ceramic substrate (S101), disposing a protective film (S102), performing a blasting process (S103), disposing a covering member (S104), and removing the protective film (S105), and may further include polishing or grinding (S106).

[0063] Preparing a ceramic substrate (S101), as shown in FIG. 3B, preferably includes preparing a ceramic plate (S11), disposing a protective film (S12), forming a recess and a through hole (S13), removing the protective film (S14), filling with a metal paste (S15), firing the metal paste (S16), and polishing or grinding (S17).

[0064] FIG. 4A is a cross-sectional view showing the preparation of a ceramic substrate. FIG. 4B is a cross-sectional view showing the disposition of a protective film. FIG. 4C is a cross-sectional view showing blasting. FIG. 4D is a cross-sectional view showing the disposition of a covering member. FIG. 4E is a cross-sectional view showing the removal of the protective film.

[0065] FIG. 5A is a cross-sectional view showing the preparation of a ceramic plate in preparing a ceramic substrate. FIG. 5B is a cross-sectional view showing the disposition of a protective film in preparing a ceramic substrate. FIG. 5C is a cross-sectional view showing the formation of a through hole in preparing a ceramic substrate. FIG. 5D is a cross-sectional view showing the removal of the protective film in preparing a ceramic substrate. FIG. 5E is a cross-sectional view showing the filling with a metal paste in preparing a ceramic substrate. FIG. 5F is a cross-sectional view showing the firing of the metal paste in preparing a ceramic substrate. FIG. 5G is a cross-sectional view showing the polishing or grinding in preparing a ceramic substrate.

[0066] (S101: Preparing a ceramic substrate) In preparing a ceramic substrate (S101), as shown in FIG. 4A, a ceramic substrate 100 is prepared, which includes a ceramic plate 1 having a first recess 1a disposed on a first surface 1A, a second recess 1b disposed on a second surface 1B opposite to the first surface 1A, and a through hole 1c connecting the first recess 1a and the second recess 1b, and a metal member 2 disposed continuously with the first recess 1a, the second recess 1b, and the through hole 1c.

[0067] <S11: Preparing a ceramic plate> In preparing the ceramic plate (S11), as shown in FIG. 5A, it is preferable to prepare a flat ceramic plate 1.

[0068] The ceramic plate 1 may be a ceramic precursor before sintering or a sintered ceramic, but it is preferable that it is a sintered ceramic in that there is no dimensional variation due to firing. Further, when using a ceramic precursor before sintering as the ceramic plate 1, it is preferable to sinter and use the ceramic plate 1 before arranging the protective film (S12).

[0069] The thickness of the flat ceramic plate 1 is not particularly limited, but is preferably 50 μm or more and 500 μm or less, and more preferably 80 μm or more and 400 μm or less.

[0070] <S12: Arranging a protective film> In arranging the protective film (S12), as shown in FIG. 5B, the protective film 3 is arranged on the first surface 1A and the second surface 1B of the ceramic plate 1.

[0071] The position and size of the protective film 3 to be arranged are not particularly limited, and on the first surface 1A and the second surface 1B of the ceramic plate 1, it may be arranged partially or entirely, but it is preferable to arrange a protective film having a desired shape pattern entirely on the first surface 1A and the second surface 1B.

[0072] The shape of the protective film 3 is not particularly limited and can be appropriately selected according to the arrangement of the electrodes of the light-emitting element and the electrodes of the mounting substrate, etc. Specifically, it is preferable to arrange the protective film 3 in a region that does not correspond to the electrodes of the light-emitting element and the electrodes of the mounting substrate.

[0073] The type of the protective film 3 is not particularly limited, and examples include a resist, a dry film, etc. The resist may be a positive type or a negative type.

[0074] When using a resist as the protective film 3, in forming the concave portions and through holes (S13), by exposure and development, a region of the first surface 1A of the ceramic plate 1 other than the first concave portion 1a on the first surface 1A of the ceramic plate 1 and the second surface 1B of the ceramic plate 1 other than the second concave portion 1b on the second surface 1B of the ceramic plate 1 are covered to form a protective film.

[0075] <S13: Forming concave portions and through holes> In forming the concave portions and through holes (S13), as shown in FIG. 5C, a first concave portion 1a is formed on the first surface 1A of the ceramic plate 1, a second concave portion 1b is formed on the second surface 1B opposite to the first surface 1A, and a through hole 1c connecting the first concave portion 1a and the second concave portion 1b is formed. The first concave portion 1a, the second concave portion 1b, and the through hole 1c are formed in a region of the ceramic plate 1 where the protective film 3 is not disposed in disposing the protective film (S12).

[0076] There is no particular limitation on the method of forming the first concave portion 1a, the second concave portion 1b, and the through hole 1c, and it can be appropriately selected according to the type of the protective film 3. For example, methods such as etching the ceramic plate 1, blasting, and laser processing can be mentioned. In the method of etching treatment, it may be wet etching or dry etching. These methods may be performed alone or in combination of two or more.

[0077] <S14: Removing the protective film> In removing the protective film (S14), as shown in FIG. 5D, from the ceramic plate 1 in which a first concave portion 1a is formed on the first surface 1A of the ceramic plate 1, a second concave portion 1b is formed on the second surface 1B opposite to the first surface 1A, and a through hole 1c connecting the first concave portion 1a and the second concave portion 1b is formed by forming the concave portions and through holes (S13), the protective film 3 is removed.

[0078] As a method for removing the protective film 3, there are no particular restrictions, and it can be appropriately selected according to the type of the protective film 3. It may be removed by peeling, or may be removed by polishing or grinding.

[0079] <S15: Filling with a metal paste> In filling with a metal paste (S15), as shown in FIG. 5E, the first concave portion 1a, the second concave portion 1b, and the through hole 1c of the ceramic plate 1 are filled with the metal paste 20.

[0080] In filling with a metal paste (S15), it is preferable to arrange the metal paste 20 so as to cover not only the first concave portion 1a, the second concave portion 1b, and the through hole 1c of the ceramic plate 1 but also at least a part of the first surface 1A and the second surface 1B of the ceramic plate 1. Thereby, when the metal paste 20 is fired in firing the metal paste (S16), even if the volume of the metal paste 20 decreases, the thickness of the metal member 2 can be made sufficient.

[0081] - Metal paste 20 - FIG. 6A is an enlarged cross-sectional view schematically showing an enlarged state of a ceramic plate with a metal paste disposed therein in preparing a ceramic substrate. FIG. 6B is an enlarged cross-sectional view schematically showing a state of a metal member obtained by sintering the ceramic plate with the metal paste disposed therein shown in FIG. 6A.

[0082] The metal paste 20 is not particularly limited, but it is preferable to contain the metal powder 11 and the active metal powder 12 in terms of improving the adhesion to the ceramic plate 1, and further contains other components as necessary.

[0083] -- Metal powder -- The metal powder 11 is not particularly limited, and examples thereof include silver, copper, silver-copper eutectic alloy, copper-zinc eutectic alloy, copper-tin eutectic alloy, etc. These may be used alone or in combination of two or more. Among these, a silver-copper eutectic alloy is preferable.

[0084] The melting point of the metal powder 11 is not particularly limited, but is preferably 700°C or higher and 1,200°C or lower, more preferably 700°C or higher and 1,100°C or lower, and still more preferably 750°C or higher and 900°C or lower.

[0085] --Active metal powder-- There are no particular restrictions on the active metal powder 12, and examples include TiH2, CeH2, ZrH2, MgH2, etc. These may be used alone or in combination of two or more.

[0086] --Other components-- There are no particular restrictions on the other components in the metal paste 20, and examples include an organic binder 13, an inorganic filler 14, a reducing agent such as an organic acid, etc. These may be used alone or in combination of two or more.

[0087] There are no particular restrictions on the organic binder 13, and examples include thermosetting resins, thermoplastic resins, etc. Specific examples of the organic binder 13 include epoxy resins, silicone resins, acrylic resins, urethane resins, polyvinyl-based resins, ethyl cellulose resins, phenol resins, polyimide resins, polyurethane resins, melamine resins, polyurea resins, etc. Also, as the organic binder 13, a solvent and a resin material generally used as a via material may be used. These may be used alone or in combination of two or more. Since the organic binder 13 functions as a sintering binder, it is decomposed and evaporated and removed during the firing (S16) of the metal paste.

[0088] There are no particular restrictions on the inorganic filler 14, and examples include ceramic fillers, metal fillers, glass fillers, etc. These may be used alone or in combination of two or more. Among these, as the inorganic filler 14, a ceramic filler is preferred. When the metal paste 20 contains the inorganic filler 14, the thermal conductivity and heat dissipation of the metal member 2 can be improved.

[0089] There is no particular limitation on the ceramic filler, and examples thereof include aluminum nitride (AlN), silicon nitride (Si3N4), aluminum oxide (Al2O3), silicon carbide (SiC), and the like.

[0090] Further, as the inorganic filler 14, a material having a linear expansion coefficient of 8 ppm or less is preferable. Thereby, the linear coefficient of the metal member 2 can be reduced, and the thermal shock characteristics can be improved.

[0091] There is no particular limitation on the median diameter of the inorganic filler 14, but it is preferably 1 μm or more and 50 μm or less, and more preferably 2 μm or more and 15 μm or less.

[0092] Further, as the inorganic filler 14, a material having a linear expansion coefficient of 5 ppm or less and a high thermal conductivity of 100 W / m·K or more is preferable. Examples of such a material include the above-mentioned ceramic filler. By dispersing and arranging such a material in the metal member 2, the difference in linear expansion coefficient can be alleviated and the reliability such as thermal shock characteristics can be improved.

[0093] There is no particular limitation on the thermal conductivity of the inorganic filler 14, but at a measurement temperature of 300 K, it is preferably 20 W / (m / K) or more, and more preferably 30 W / (m / K) or more.

[0094] When the total content of the metal powder 11, the active metal powder 12, and the inorganic filler 14 in the metal paste 20 is 100% by mass, the metal powder 11 is preferably 40% by mass or more and 99% by mass or less, the active metal powder 12 is preferably 0.5% by mass or more and 15% by mass or less, and the inorganic filler 14 is preferably 1% by mass or more and 50% by mass or less.

[0095] <S16: Firing the metal paste> In baking the metal paste (S16), as shown in FIG. 5F, the metal paste 20 filled in the first recess 1a, the second recess 1b, and the through hole 1c of the ceramic plate 1 is baked to form the metal member 2 when filling the metal paste (S15). When the metal paste 20 is arranged so as to cover at least a part of the first surface 1A and the second surface 1B of the ceramic plate 1 in filling the metal paste (S15), the metal paste 20 is baked in the same manner to form the metal member 2.

[0096] In baking the metal paste (S16), after filling the metal paste (S15) and before baking the metal paste 20, it is preferable to dry it. The drying temperature is not particularly limited, and for example, a temperature lower than the baking temperature of the metal paste 20 can be mentioned.

[0097] The baking temperature when baking the metal paste 20 is not particularly limited, but is preferably 700°C or higher and 1,100 or lower, more preferably 720°C or higher and 1,000°C or lower, and still more preferably 750°C or higher and 900°C or lower.

[0098] The baking time when baking the metal paste 20 is not particularly limited, but is preferably 5 minutes or more and 90 minutes or less, more preferably 10 minutes or more and 60 minutes or less, and still more preferably 15 minutes or more and 30 minutes or less.

[0099] The metal member 2 produced using the metal paste 20, as shown in FIG. 6B, includes, as an example, a metal 15, a metal compound 16, and an inorganic filler 14. The organic binder 13 is evaporated and removed by baking the metal paste 20.

[0100] When the total content of the metal 15, the metal compound 16, and the inorganic filler 14 in the metal member 2 is 100% by mass, it is preferable that the metal 15 is 40% by mass or more and 95% by mass or less, the metal compound 16 is 1% by mass or more and 10% by mass or less, and the inorganic filler 14 is 5% by mass or more and 50% by mass or less, respectively. By including the inorganic filler 14 in a predetermined ratio, the metal member 2 can reduce volume shrinkage. Further, the metal member 2 can disperse the inorganic filler 14 in the continuous metal 15 by including the metal 15 in a predetermined ratio.

[0101] The metal 15 is a metal member that serves as the core of the metal member 2 together with the inorganic filler 14 in the metal member 2. The metal 15 is arranged in a state where the inorganic filler 14 is dispersed.

[0102] In firing the metal paste (S16), the metal powder 11 in the metal paste 20 is fired to become the metal 15. Therefore, the type of metal of the metal 15 is specified by the type of metal of the metal powder 11, and examples include silver, copper, silver-copper eutectic alloy, copper-zinc eutectic alloy, copper-tin eutectic alloy, and the like. Among these, a silver-copper eutectic alloy is preferable.

[0103] In the metal member 2, the inorganic filler 14 is arranged in a state where a plurality of particles are dispersed. Here, the plurality of inorganic fillers 14 indicates that the inorganic filler 14 is not one particle but a plurality of particles.

[0104] Further, in a cross-sectional view in the thickness direction of the ceramic substrate 100 of the metal member 2, the inorganic filler 14 is 2 per 100 μm 2 and preferably arranged in the range of 10 μm 2 or more and 75 μm or less.

[0105] The metal compound 16 is formed by firing the active metal powder 12. By firing the metal paste 20, a reaction layer of the inorganic filler 14 and the active metal powder 12 is formed on the surface of the inorganic filler 14. The metal compound 16 is mainly disposed on at least a part or all of the surface of the inorganic filler 14 and at least a part of the inner walls of the first recess 1a, the second recess 1b, and the through hole 1c in the ceramic plate 1. As the metal compound 16, a filler surface metal compound 16a disposed on the surface of the inorganic filler 14 and a wall surface metal compound 16b disposed on at least a part of the inner walls of the first recess 1a, the second recess 1b, and the through hole 1c in the ceramic plate 1 are the metal compound 16. Preferably, by firing the active metal powder 12 and the components of the inner walls of the first recess 1a, the second recess 1b, and the through hole 1c in the inorganic filler 14 and the ceramic plate 1, the filler surface metal compound 16a and the wall surface metal compound 16b are disposed as reaction products.

[0106] The filler surface metal compound 16a is the metal compound 16 and is disposed so as to cover at least a part or all of the surface of the inorganic filler 14. For example, when the inorganic filler 14 is AlN or Si3N4, the filler surface metal compound 16a reacts with TiH2 of the active metal powder 12 before firing and is formed as TiN on the surface of the inorganic filler 14 as an example. And the filler surface metal compound 16a has unevenness continuously formed in a zigzag shape on its surface, and the surface of the inorganic filler 14 also has unevenness formed in a zigzag shape. Then, the inorganic filler 14 having the filler surface metal compound 16a disposed on its surface is in a state of being dispersed in the continuous metal member 2.

[0107] The wall surface metal compound 16b, as the metal compound 16, is disposed on at least a part of the inner walls of the first recess 1a, the second recess 1b, and the through hole 1c in the ceramic plate 1. For example, when the ceramic plate 1 is at least one selected from silicon nitride, aluminum nitride, and boron nitride, and the active metal powder 12 before firing is, for example, TiH2 and TiN, the wall surface metal compound 16b generates a reaction product and is formed as a compound on the inner walls of the first recess 1a, the second recess 1b, and the through hole 1c in the ceramic plate 1. The wall surface metal compound 16b is in a state where irregularities are continuously formed in a jagged shape on the inner walls of the first recess 1a, the second recess 1b, and the through hole 1c in the ceramic plate 1, and improves the connection strength between the inner walls of the first recess 1a, the second recess 1b, and the through hole 1c in the ceramic plate 1 and the metal member 2.

[0108] <S17: Polishing or grinding> In polishing or grinding (S17), as shown in FIG. 5G, the metal member 2 exposed on the first surface 1A and the second surface 1B of the ceramic plate 1 of the ceramic substrate 100 obtained by firing the metal paste (S16) and the surface of the ceramic plate 1 exposed on the first surface 1A and the second surface 1B of the ceramic plate 1 are polished or ground.

[0109] The ceramic substrate 100 obtained by firing the metal paste (S16) may be used as it is for disposing the protective film (S102), for example, when the metal paste 20 is filled only in the first recess 1a, the second recess 1b, and the through hole 1c of the ceramic plate 1 in filling the metal paste (S15). However, when the metal paste 20 is disposed so as to cover at least a part of the first surface 1A and the second surface 1B of the ceramic plate 1, the first surface 1A and the second surface 1B of the ceramic plate 1 and the surface (exposed surface) of the metal member 2 can be made substantially flush by further polishing or grinding (S17).

[0110] Also, when firing the metal paste (S16), the first surface 1A and the second surface 1B of the ceramic plate 1 may be blackened, but this can be removed by polishing or grinding.

[0111] (S102: Disposing a protective film) In disposing the protective film (S102), as shown in FIG. 4B, the protective film 3 is disposed on at least a part of the metal member 2 of the ceramic substrate 100.

[0112] In disposing the protective film (S102), the protective film 3 may be disposed on a part of the first surface 1A of the ceramic plate 1 in the ceramic substrate 100, or the protective film 3 may be disposed continuously on a part of the metal member 2 of the ceramic substrate 100 and a part of the first surface 1A of the ceramic plate 1.

[0113] In disposing the protective film (S102), the protective film 3 may be disposed at least on the first surface 1A side of the ceramic plate 1, but may also be disposed on the second surface 1B side of the ceramic plate 1.

[0114] There is no particular limitation on the disposition of the protective film 3. On the first surface 1A and the second surface 1B of the ceramic plate 1 in the ceramic substrate 100, it may be disposed on a part respectively, or may be disposed on the entire surface. However, it is preferable to dispose a protective film having a desired shape pattern on the entire first surface 1A and the second surface 1B.

[0115] There is no particular limitation on the type of the protective film 3. For example, a resist, a dry film, etc. may be mentioned. The resist may be a positive type or a negative type.

[0116] There is no particular limitation on the planar shape of the protective film 3. It can be appropriately selected according to the arrangement of the electrodes on the mounting substrate side, etc. For example, polygons such as triangles, quadrilaterals, pentagons, hexagons, circles, ellipses, etc. may be mentioned. Also, a shape combining these shapes may be used. Specifically, it is preferable to dispose the protective film 3 in a region not corresponding to the electrodes on the mounting substrate side.

[0117] The shape of the protective film 3 disposed on the first surface 1A of the ceramic plate 1 in the ceramic substrate 100 may be the same as or different from the shape of the protective film 3 disposed on the second surface 1B of the ceramic plate 1 in the ceramic substrate 100. The shape of the protective film 3 disposed on the first surface 1A and the shape of the protective film 3 disposed on the second surface 1B can be appropriately selected according to the structure, shape, dimensions, etc. of the light-emitting element.

[0118] Specific examples of the protective film 3 are shown in FIGS. 7A to 9C. FIG. 7A is a plan view showing an example of the shape pattern of the protective portion in the protective film used for the first surface of the ceramic substrate when disposing the protective film. FIG. 7B is a plan view showing an example of the shape pattern of the protective portion in the protective film used for the second surface of the ceramic substrate when disposing the protective film. FIG. 8A is an enlarged view of a metal member in a plan view of a wiring substrate manufactured using the region VIIIA of the protective film shown in FIG. 7A. FIG. 8B is a cross-sectional view of the VIIIB-VIIIB cross-section of the wiring substrate of FIG. 8A. FIG. 8C is a cross-sectional view of the VIIIC-VIIIC cross-section of the wiring substrate of FIG. 8A. FIG. 9A is an enlarged view of a metal member in a plan view of a wiring substrate manufactured using the region VIIIIA of the protective film shown in FIG. 7A. FIG. 9B is a cross-sectional view of the VIIIIB-VIIIIB cross-section of the wiring substrate of FIG. 9A. FIG. 9C is a cross-sectional view of the VIIIIC-VIIIIC cross-section of the wiring substrate of FIG. 9A. Note that FIGS. 7B, 7C, 8B, and 8C illustrate with the first surface of the wiring substrate 200 on the left side of the drawing and the second surface of the wiring substrate 200 on the right side of the drawing.

[0119] In FIGS. 7A and 7B, the colored portion is the protective film 3. The portion protected by the protective film 3 becomes the convex portion 2a after the blasting process (S103). Since the convex portion 2a includes the metal member 2, it can correspond to the electrode positions of electronic components with various wiring patterns. Therefore, the manufacturing method of the wiring substrate according to the embodiment includes the blasting process (S103), so that wiring corresponding to the electrode positions of electronic components can be easily manufactured even for wiring patterns with a plurality of shapes, complex shapes, and small dimensions as shown in FIG. 7A.

[0120] When the protective film 3 shown in FIG. 7A is used, the metal member 2 covered by the region VIIIA in FIG. 7A becomes a convex portion 2a exposed on the first surface 1A of the ceramic plate 1 in the wiring substrate 200 after the blasting process. In this case, the convex portion 2a has a triangular shape indicated by a solid line in FIG. 8A. In FIG. 8A, the dotted line is a virtual line showing the shape of the bottom of the first concave portion 1a of the ceramic plate 1. As shown in FIGS. 8A to 8C, the shape of the metal member 2 in the first concave portion 1a of the ceramic plate 1 and the shape of the upper surface of the convex portion 2a exposed on the first surface 1A are different.

[0121] As another example, when the protective film 3 shown in FIG. 7A is used, the metal member 2 covered by the region VIIIIA in FIG. 7A becomes a convex portion 2a exposed on the first surface 1A of the ceramic plate 1 in the wiring substrate 200 after the blasting process. In this case, the convex portion 2a has the shape indicated by a solid line in FIG. 9A. In FIG. 8A, the dotted line is a virtual line showing the shape of the bottom of the first concave portion 1a of the ceramic plate 1. As shown in FIGS. 9A to 9C, the shape of the metal member 2 in the first concave portion 1a of the ceramic plate 1 and the shape of the upper surface of the convex portion 2a exposed on the first surface 1A are different. Further, in FIG. 9B, unlike the case of FIG. 8B, the covering member 4 is not disposed between one metal member 2 and the other metal member 2 on the surface having the covering member 4.

[0122] (S103: Performing blasting process) In performing the blasting process (S103), as shown in FIG. 4C, at least a part of the other portion of the metal member 2 other than the part of the metal member 2 where the protective film 3 is disposed and at least a part of the first surface 1A of the ceramic plate 1 are blasted. Thereby, a concave portion 5 is formed in which at least a part of the other portion of the metal member 2 and at least a part of the first surface 1A of the ceramic plate 1 are removed. In other words, with respect to the other portion of the metal member 2 other than the part of the metal member 2 where the protective film 3 is disposed and the first surface 1A of the ceramic plate 1, a part of the metal member 2 where the protective film 3 is disposed, and further, at least a part of the first surface 1A of the ceramic plate 1, if necessary, become the convex portion 2a.

[0123] In the blasting process (S103), at least the first surface 1A side of the ceramic plate 1 may be blasted, but the second surface 1B side of the ceramic plate 1 may also be blasted. When the protective film 3 is disposed on the second surface 1B side of the ceramic plate 1 in the step of disposing the protective film (S102), in the blasting process (S103), preferably, the second surface 1B side of the ceramic plate 1 is also blasted. As a result, a recess is formed in which other parts of the metal member 2 and a part of the second surface 1B of the ceramic plate 1 are removed.

[0124] Note that the second surface 1B of the ceramic plate 1 may be processed by other methods such as etching and laser processing to form a recess.

[0125] The blasting process may be wet blasting or dry blasting. Among these, dry blasting is preferable in that a predetermined shape can be formed regardless of the type of solution.

[0126] By the blasting process, as described in the item of [wiring board] above, the convex portion 2a has the structure shown in FIG. 2. As a result, the surface area of the metal member 2 in the wiring board 200 increases, and the thermal conductivity and heat dissipation performance are improved. Also, the conductivity in the plan view direction of the wiring board 200 is improved.

[0127] Also, by the blasting process, the center of gravity of the upper surface of the convex portion 2a of the metal member 2 and the center of gravity of the lower surface of the convex portion 2a can be set at different positions. In this way, in the cross-sectional view in the thickness direction of the wiring board 200, the shape of the metal member 2 can be made asymmetric, and the wiring pattern can be freely designed.

[0128] The protective film 3 is not disposed, and at least a part of the surface of the other part 2b of the upper surface of the metal member 2 and the first surface 1A of the ceramic plate 1 other than the upper surface of the convex portion 2a of the blasted metal member 2 becomes rougher than a part of the surface of the metal member 2 where the protective film 3 is disposed. The surface roughness Ra of at least a part of the other part 2b of the upper surface of the metal member 2 and the first surface 1A of the ceramic plate 1 other than the upper surface of the convex portion 2a of the metal member 2 where the protective film 3 is disposed is as described in the item [wiring board] above.

[0129] Also, the surface roughness Ra of at least a part of the other part of the upper surface of the convex portion 2a of the metal member 2 where the protective film 3 is disposed and the first surface 1A of the ceramic plate 1 is also as described in the item [wiring board] above.

[0130] When the second surface 1B of the ceramic plate 1 is blasted in the same manner as the first surface 1A of the ceramic plate 1, at least a part of the metal member 2 where the protective film is disposed and at least a part of the second surface of the ceramic plate, and at least a part of the other part of the metal member 2 where the protective film is not disposed and at least a part of the other part of the second surface of the ceramic plate are similarly formed with convex portions, and have the same surface roughness Ra as when the first surface 1A of the ceramic plate 1 is blasted.

[0131] (S104: Disposing a covering member) In disposing the covering member (S104), as shown in FIG. 4D, the covering member 4 is disposed in the recess 5 in which at least a part of the other part 2b of the upper surface of the metal member 2 other than the convex portion 2a and the first surface 1A of the ceramic plate 1 are removed by blasting.

[0132] In disposing the covering member (S104), as another form, the covering member 4 may be disposed so as to cover the protective film 3.

[0133] (S105: Removing the protective film) In removing the protective film (S105), as shown in FIG. 4E, the protective film 3 disposed in disposing the protective film (S102) is removed.

[0134] As a method for removing the protective film 3, there are no particular limitations, and it can be appropriately selected according to the type of the protective film 3. It may be removed by peeling, or may be removed by polishing or grinding (S106).

[0135] (S106: Polishing or grinding) In polishing or grinding (S106), after arranging the covering member, the first surface 1A of the ceramic plate 1 is polished or ground. It may be used as the final wiring board 200 without performing polishing or grinding (S106). However, by polishing or grinding, the exposed surface of the covering member 4 can be flattened, and when the light-emitting element is arranged on the wiring board 200, it can be arranged without wobbling. Further, when the light-emitting element is arranged on the wiring board 200, the light from the light-emitting element can be efficiently reflected by the covering member 4 and reflected in the upward and upper oblique directions.

Example

[0136] The present invention will be specifically described below with reference to examples, but the embodiments are not limited to the examples in any way.

[0137] (Example 1) A ceramic substrate 100 having a thickness of 330 μm shown in FIG. 4A was prepared. The ceramic substrate 100 was prepared by filling the first recess 1a, the second recess 1b, and the through hole 1c of the ceramic plate 1 with the metal paste 20 by the method described in FIGS. 5A to 5G based on the flowchart described in FIG. 3B, firing at 850° C., and polishing after firing. The metal paste 20 was prepared by mixing 89% by mass of a silver-copper eutectic alloy as the metal powder 11, 5% by mass of TiH2 as the active metal powder 12, 1% by mass of a polyvinyl ester resin as the organic binder 13, and 5% by mass of AlN as the inorganic filler 14.

[0138] Using the fabricated ceramic substrate 100, based on the flowchart shown in FIG. 3A, the wiring substrate 200 was fabricated by the method described in FIGS. 4A to 4E. Specifically, a dry film having the shape pattern shown in FIG. 7A was placed on the first surface 1A of the ceramic plate 1 in the fabricated ceramic substrate 100, and dry blasting treatment was performed. Then, using a material of a coating member containing 45% by mass of titanium oxide and 55% by mass of epoxy resin, the coating member 4 was formed from above the dry film. Next, the coating member 4 was polished and the dry film was removed to obtain the wiring substrate 200.

[0139] <Evaluation of the shape of the convex portion 2a> A cross-section in the thickness direction of the wiring substrate 200 of Example 1 was fabricated using a focused ion beam scanning electron microscope (FIB-SEM) "Heloes450s" manufactured by FEI Company, and the shape of the convex portion 2a of the metal member 2 was observed. As a result, it had the shape shown in FIG. 2.

[0140] <Evaluation of the surface roughness Ra> In the wiring substrate 200 of Example 1, the surface roughness Ra of the upper surface of the convex portion 2a of the metal member 2 where the dry film was placed and the other portion 2b of the upper surface of the metal member 2 other than the upper surface of the convex portion 2a of the metal member 2 where the dry film was not placed were measured using a stylus type surface roughness meter (Surfcorder SE3500 manufactured by Kosaka Laboratory Ltd.) equipped with a diamond stylus having a tip curvature radius r of 2 μm in accordance with JIS B 0601:2013.

[0141] As a result, the surface roughness Ra of the upper surface of the convex portion 2a of the metal member 2 where the dry film was placed was 120 nm, and the surface roughness Ra of the other portion 2b of the upper surface of the metal member 2 other than the upper surface of the convex portion 2a of the metal member 2 where the dry film was not placed was 424 nm.

[0142] <Evaluation of adhesion> In the wiring board 200 of Example 1, the adhesion of the coating member 4 on the upper surface of the convex portion 2a of the metal member 2 where the dry film was disposed and on the other portion 2b of the upper surface of the metal member 2 other than the upper surface of the convex portion 2a of the metal member 2 where the dry film was not disposed was evaluated by a shear test using a bond tester manufactured by DAGE Products Co., Ltd.

[0143] As a result, the adhesion of the coating member 4 on the other portion 2b of the upper surface of the metal member 2 other than the upper surface of the convex portion 2a of the metal member 2 where the dry film was not disposed was higher than the adhesion of the coating member 4 on the upper surface of the convex portion 2a of the metal member 2 where the dry film was disposed.

[0144] 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 by the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, replacements, additions, changes, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

[0145] In addition to the above embodiments, the following supplementary notes are further disclosed. (Supplementary Note 1) Preparing a ceramic substrate including a ceramic plate having a first recess disposed on a first surface, a second recess disposed on a second surface opposite to the first surface, and a through hole connecting the first recess and the second recess, and a metal member disposed continuously with the first recess, the second recess, and the through hole; Disposing a protective film on at least a part of the metal member of the ceramic substrate; Performing a blasting process on the other part of the metal member other than the part of the metal member on which the protective film is disposed and at least a part of the first surface of the ceramic plate; Placing a covering member in a recess formed by removing at least a part of the other part of the metal member and at least a part of the first surface of the ceramic plate by the blasting process; Removing the protective film; A method for manufacturing a wiring board including these steps. (Appendix 2) The method for manufacturing a wiring board according to Appendix 1, wherein in preparing the ceramic substrate, the ceramic plate is a sintered ceramic plate. (Appendix 3) The method for manufacturing a wiring board according to Appendix 1 or 2, wherein in placing the protective film, the protective film is continuously placed on a part of the metal member of the ceramic substrate and a part of the first surface of the ceramic plate. (Appendix 4) The method for manufacturing a wiring board according to any one of Appendices 1 to 3, wherein in placing the protective film, the shape of the protective film in plan view is a shape composed of a polygon, a circle, an ellipse, or a combination thereof. (Appendix 5) The method for manufacturing a wiring board according to any one of Appendices 1 to 4, wherein in placing the covering member, the covering member includes a light-reflective member. (Appendix 6) The method for manufacturing a wiring board according to any one of Appendices 1 to 5, wherein in placing the covering member, the covering member is placed so as to cover the protective film. (Appendix 7) The method for manufacturing a wiring board according to Appendix 6, further including polishing or grinding the exposed surface of the covering member after placing the covering member. (Appendix 8) The method for manufacturing a wiring board according to any one of Appendices 1 to 7, wherein in preparing the ceramic substrate, the first recess, the second recess, and the through hole are filled with a metal paste, and the metal paste is fired to form the metal member. (Appendix 9) The method for manufacturing a wiring board according to Appendix 8, wherein in preparing the ceramic substrate, the firing temperature is 700°C or higher and 1,100°C or lower. (Supplementary Note 10) In preparing the ceramic substrate, the maximum diameter in the plan view of the metal member disposed in the first recess is larger than the maximum diameter in the plan view of the metal member disposed in the through hole, which is the method for manufacturing a wiring substrate according to any one of Supplementary Notes 1 to 9. (Supplementary Note 11) A ceramic substrate including a ceramic plate having a first recess disposed on a first surface, a second recess disposed on a second surface opposite to the first surface, and a through hole connecting the first recess and the second recess, and a metal member continuously disposed in the first recess, the second recess, and the through hole, and having a convex portion whose upper surface on the first surface side is convex with respect to the first surface. A covering member disposed so as to be in contact with at least a part of the other part of the upper surface of the metal member and the first surface of the ceramic plate other than the upper surface of the convex portion. Comprising A wiring substrate in which the surface roughness Ra of at least a part of the other part of the upper surface of the metal member and the first surface of the ceramic plate is 350 nm or more. (Supplementary Note 12) The wiring substrate according to Supplementary Note 11, wherein the surface roughness Ra of the upper surface of the convex portion is 10 nm or more and 300 nm or less. (Supplementary Note 13) In a cross-sectional view in the thickness direction of the wiring substrate, the shape of the convex portion is a shape in which the width continuously widens from the upper surface of the convex portion toward the lower surface of the convex portion, and in a cross-sectional view in the thickness direction of the wiring substrate, a line forming the other part of the upper surface of the convex portion from the upper surface of the convex portion toward the lower surface of the convex portion is a curve, which is the wiring substrate according to any one of Supplementary Notes 11 or 12. (Supplementary Note 14) The wiring substrate according to any one of Supplementary Notes 11 to 13, wherein the maximum diameter in the plan view of the metal member disposed in the first recess is larger than the maximum diameter in the plan view of the metal member disposed in the through hole. (Supplementary Note 15) The wiring substrate according to any one of Supplementary Notes 11 to 14, wherein the area of the upper surface of the convex portion is smaller than the area of the lower surface of the convex portion. (Supplementary Note 16) The wiring board according to any one of Appendices 11 to 15, wherein the center of gravity of the upper surface of the convex portion and the center of gravity of the lower surface of the convex portion are at different positions. (Appendix 17) The wiring board according to any one of Appendices 11 to 16, wherein the thickness of the ceramic plate is 50 μm or more and 500 μm or less. (Appendix 18) The wiring board according to any one of Appendices 11 to 17, wherein the average depth of the first concave portion and the second concave portion is 1 / 10 or more and 2 / 5 or less with respect to the thickness of the ceramic plate.

Explanation of Reference Numerals

[0146] 1... Ceramic plate 1a... First concave portion 1b... Second concave portion 1c... Through hole 1A... First surface 1B... Second surface 2... Metal member 2a... Convex portion 2b, 2r1, 2r2... Other parts of the upper surface of the metal member 2 other than the upper surface of the convex portion 2a of the metal member 2 3... Protective film 3a, 3b... Protective portions 4... Coating member 5... Concave portion 11... Metal powder 12... Active metal powder 13... Organic binder 14... Inorganic filler 15... Metal 16... Metal compound 16a... Filler surface metal compound 16b... Wall surface metal compound 20... Metal paste 100... Ceramic substrate 200... Wiring board

Claims

1. Preparing a ceramic substrate comprising a ceramic plate having a first recess disposed on a first surface, a second recess disposed on a second surface opposite to the first surface, and a through hole connecting the first recess and the second recess, and a metal member disposed continuously in the first recess, the second recess, and the through hole; Disposing a protective film on at least a part of the metal member of the ceramic substrate; Performing a blasting process on at least a part of the other part of the metal member and the first surface of the ceramic plate other than the part of the metal member on which the protective film is disposed; Disposing a covering member in a recess formed by removing at least a part of the other part of the metal member and the first surface of the ceramic plate by the blasting process; Removing the protective film; A method for manufacturing a wiring board including the above steps.

2. The method for manufacturing a wiring board according to claim 1, wherein in preparing the ceramic substrate, the ceramic plate is a sintered ceramic plate.

3. The method for manufacturing a wiring board according to claim 1, wherein in disposing the protective film, the protective film is disposed continuously on a part of the metal member of the ceramic substrate and a part of the first surface of the ceramic plate.

4. The method for manufacturing a wiring board according to claim 1, wherein in disposing the protective film, the shape of the protective film in plan view is a shape composed of a polygon, a circle, an ellipse, or a combination thereof.

5. The method for manufacturing a wiring board according to claim 1, wherein in disposing the covering member, the covering member includes a light-reflective member.

6. The method for manufacturing a wiring board according to claim 1, wherein in disposing the covering member, the covering member is disposed so as to cover the protective film.

7. The method for manufacturing a wiring board according to claim 6, further including polishing or grinding an exposed surface of the covering member after disposing the covering member.

8. The method for manufacturing a wiring board according to claim 1, wherein in preparing the ceramic substrate, a metal paste is filled in the first recess, the second recess, and the through hole, and the metal paste is fired to form the metal member.

9. The method for manufacturing a wiring board according to claim 8, wherein in preparing the ceramic substrate, the firing temperature is 700 °C or higher and 1,100 °C or lower.

10. In preparing the ceramic substrate, the maximum diameter in the plan view of the metal member disposed in the first recess is larger than the maximum diameter in the plan view of the metal member disposed in the through hole. The method for manufacturing a wiring substrate according to claim 1.

11. A ceramic substrate comprising: a ceramic plate having a first recess disposed on a first surface, a second recess disposed on a second surface opposite to the first surface, and a through hole connecting the first recess and the second recess; and a metal member continuously disposed in the first recess, the second recess, and the through hole, and having a convex portion whose upper surface on the first surface side is convex with respect to the first surface. A covering member disposed so as to be in contact with at least a part of the other part of the upper surface of the metal member and the first surface of the ceramic plate other than the upper surface of the convex portion. Comprising A wiring substrate, wherein the surface roughness Ra of at least a part of the other part of the upper surface of the metal member and the first surface of the ceramic plate is 350 nm or more.

12. The wiring substrate according to claim 11, wherein the surface roughness Ra of the upper surface of the convex portion is 10 nm or more and 300 nm or less.

13. In a cross-sectional view in the thickness direction of the wiring substrate, the shape of the convex portion is a shape in which the width continuously increases from the upper surface of the convex portion toward the lower surface of the convex portion, and in a cross-sectional view in the thickness direction of the wiring substrate, a line forming the other part of the upper surface of the convex portion from the upper surface of the convex portion toward the lower surface of the convex portion is a curve. The wiring substrate according to claim 11.

14. The maximum diameter in the plan view of the metal member disposed in the first recess is larger than the maximum diameter in the plan view of the metal member disposed in the through hole. The wiring substrate according to claim 11.

15. The area of the upper surface of the convex portion is smaller than the area of the lower surface of the convex portion. The wiring substrate according to claim 11.

16. The center of gravity of the upper surface of the convex portion and the center of gravity of the lower surface of the convex portion are at different positions. The wiring substrate according to claim 11.

17. The thickness of the ceramic plate is 50 μm or more and 400 μm or less. The wiring substrate according to claim 11.

18. The average depth of the first recess and the second recess is 1 / 10 or more and 2 / 5 or less with respect to the thickness of the ceramic plate, respectively. The wiring substrate according to claim 11.

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