Method for manufacturing substrate

Abstract

Provided is a method for manufacturing a substrate capable of forming a hole penetrating a ceramic substrate with high precision. The method for manufacturing a substrate comprises: a step for preparing a ceramic substrate having a first surface and a second surface positioned on the opposite side of the first surface; a first processing step in which a first region of the first surface is irradiated with a first laser beam having a first pulse width, thereby ablating the first region of the ceramic substrate; and a second processing step in which, in a plan view, a second laser beam having a second pulse width larger than the first pulse width is irradiated to a second region separated from the first region of either the first surface or the second surface, and a third region including the first region and the second region is thermally processed, and in the second processing step, the second laser beam having a second pulse width larger than the first pulse width is irradiated to the second region, which is separated from the first region of either the first surface or the second surface. The third region and a region surrounded by the third region form a hole penetrating from the first surface to the second surface.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a substrate. Background Art

[0002] Conventionally, there is known a substrate having wiring on which a light emitting element and various electrical elements can be mounted. In addition, Patent Document 1 discloses a technique for forming a through hole penetrating a ceramic substrate by laser processing.

[0003] <Prior Art Literature>

[0004] <Patent Documents>

[0005] Patent Document 1: (Japan) Patent Publication No. 2019-511115 Summary of the invention

[0006] <Problems to be Solved by the Invention>

[0007] Ceramic substrates are harder than substrates made of other materials, so it is difficult to process them with high precision. On the other hand, in order to achieve high-precision mounting and wiring formation of light-emitting elements and various electrical components on the substrate, the position and shape of the holes that penetrate the substrate must be highly accurate.

[0008] An object of an embodiment of the present invention is to provide a method for manufacturing a substrate capable of forming a hole penetrating a ceramic substrate with high accuracy.

[0009] <Methods used to solve the problem>

[0010] A method for manufacturing a substrate according to one embodiment of the present invention comprises: a step of preparing a ceramic substrate, the ceramic substrate having a first surface and a second surface located on the opposite side of the first surface; a first processing step of ablation-processing the first area in the ceramic substrate by irradiating the first area of ​​the first surface with a first laser having a first pulse width; a second processing step of irradiating the second area separated from the first area of ​​either the first surface or the second surface with a second laser having a second pulse width greater than the first pulse width in a plan view, so as to thermally process a third area including the first area and the second area, wherein in the second processing step, the third area and an area surrounded by the third area form a hole penetrating from the first surface to the second surface.

[0011] <Effects of the Invention>

[0012] According to the embodiment of the present invention, it is possible to provide a method for manufacturing a substrate capable of forming a hole penetrating a ceramic substrate with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic plan view showing the structure of a light-emitting device including a substrate according to an embodiment.

[0014] Figure 2 yes Figure 1 Schematic cross-sectional view of line II-II.

[0015] Figure 3 It is a schematic plan view showing a process of preparing a ceramic substrate to be manufactured in the substrate manufacturing method according to the embodiment.

[0016] Figure 4 yes Figure 3 Schematic cross-sectional view of line IV-IV.

[0017] Figure 5 This is a schematic plan view of a ceramic substrate showing a first processing step in the method for manufacturing a substrate according to the embodiment.

[0018] Figure 6 yes Figure 5 Schematic cross-sectional view along line VI-VI.

[0019] Figure 7 It is a first schematic plan view of a ceramic substrate showing a second processing step in the method for manufacturing a substrate according to the embodiment.

[0020] Figure 8 yes Figure 7 1 is a schematic cross-sectional view taken along line VIII-VIII.

[0021] Fig. 9 It is a second schematic plan view of the ceramic substrate showing the second processing step in the method for manufacturing the substrate according to the embodiment.

[0022] Fig.10 yes Fig. 9 The second schematic cross-sectional view along line XX.

[0023] Fig.11A It is a schematic plan view showing a hole formed by the method for manufacturing a substrate according to the embodiment.

[0024] Fig. 11B It is a schematic bottom view showing a hole formed by the method for manufacturing a substrate according to the embodiment.

[0025] Fig.12 yes Fig.11A Schematic cross-sectional view along line XII-XII.

[0026] Fig.13 This is a schematic plan view of a ceramic substrate showing a second processing step in the method for manufacturing a substrate according to Modification 1.

[0027] Fig.14 yes Fig.13 Schematic cross-sectional view of line XIV-XIV.

[0028] Fig.15 This is a schematic plan view of a ceramic substrate showing a first region in a method for manufacturing a substrate according to Modification Example 2.

[0029] Fig.16 yes Fig.15 Schematic cross-sectional view along line XVI-XVI of FIG.

[0030] Fig.17 1 is a first schematic plan view of the ceramic substrate showing the second region and the third region in the method for manufacturing the substrate according to Modification 2. FIG.

[0031] Fig.18 yes Fig.17 1 is a schematic cross-sectional view of line XVIII-XVIII.

[0032] Fig.19 It is a second schematic plan view of the ceramic substrate showing the second region and the third region in the method for manufacturing the substrate according to Modification Example 2.

[0033] Fig. 20 yes Fig.19 The second schematic cross-sectional view along line XX-XX.

[0034] Fig.21A This is a schematic plan view of a substrate showing holes formed by the method for manufacturing a substrate according to Modification Example 2.

[0035] Fig.21B This is a schematic bottom view of a substrate showing holes formed by the substrate manufacturing method according to Modification Example 2.

[0036] Fig.22A yes Fig.21A Schematic cross-sectional view of line XXII-XXII.

[0037] Fig. 22B This is a schematic cross-sectional view showing the structure of a light-emitting device including a substrate according to Modification Example 2.

[0038] Fig.23A This is a graph showing the reflectivity of a ceramic substrate and glass.

[0039] Fig. 23B This is a top view photograph of the holes formed by the method for manufacturing a substrate in Example 1.

[0040] Fig.24 This is a bottom view photograph of a hole formed by the method for manufacturing a substrate in Example 1.

[0041] Fig.25This is a top view photograph of the holes formed by the substrate manufacturing method of Example 2.

[0042] Fig.26 This is a bottom view photograph of a hole formed by the substrate manufacturing method of Example 2.

[0043] Fig. 27 This is a top view photograph of a hole formed by the substrate manufacturing method of the reference example.

[0044] Fig.28 This is a bottom view photograph of a hole formed by the method for manufacturing a substrate of a reference example.

[0045] Fig.29 This is a top view photograph of a hole formed by the method for manufacturing a substrate of a comparative example.

[0046] Fig.30 This is a bottom plan photograph of a hole formed by the method for manufacturing a substrate of a comparative example.

[0047] Fig.31 It is a schematic diagram for explaining the interval between the first area and the second area.

[0048] Fig.32 This is a diagram showing the relationship between the interval between the first region and the second region and the formation position deviation.

[0049] Fig.33 These are photographs of the first surface and the second surface taken after the first processing step and after the second processing step, respectively.

[0050] Fig.34 This is a cross-sectional view of a hole for explaining a first example of the shape of the inner surface of the hole.

[0051] Fig.35 It is a cross-sectional view of a hole for explaining a second example of the shape of the inner surface of the hole. DETAILED DESCRIPTION

[0052] The manufacturing method of the substrate of the embodiment of the present invention is described in detail with reference to the accompanying drawings. However, the method shown below is an example of a method for manufacturing a substrate that embodies the technical idea of ​​the present invention, and the present invention is not limited to this. In addition, the size, material, shape, relative configuration, etc. of the constituent parts recorded in the embodiment, unless otherwise specified, do not mean that the scope of the present invention is limited to this, but are only illustrative examples. In addition, in order to clearly explain, the size, positional relationship, etc. of the components shown in each of the drawings are sometimes expanded. In addition, in the following description, the same name and symbol represent the same or homogeneous components, and their detailed description is appropriately omitted. As a cross-sectional view, an end view that only shows a cross section is sometimes used.

[0053] In the following figures, directions are sometimes indicated by the X-axis, the Y-axis, and the Z-axis, which are mutually orthogonal directions. The X-direction along the X-axis and the Y-direction along the Y-axis indicate directions along the first surface of the ceramic substrate to be manufactured by the substrate manufacturing method of the embodiment. The Z-direction along the Z-axis indicates a direction orthogonal to the first surface. That is, the first surface of the ceramic substrate is parallel to the XY plane, and the Z-axis is orthogonal to the XY plane.

[0054] The direction indicated by the arrow in the X direction is described as the +X side, and the opposite side of the +X direction is described as the -X side. The direction indicated by the arrow in the Y direction is described as the +Y side, and the opposite side of the +Y direction is described as the -Y side. The direction indicated by the arrow in the Z direction is described as the upper side or the +Z side, and the opposite side of the +Z direction is described as the -Z side.

[0055] In the terminology of the present embodiment, looking down means observing an object from the +Z side or the -Z side. In addition, in the present embodiment, the surface of the object when observed from the +Z side is referred to as the "upper surface", and the surface of the object when observed from the -Z side is referred to as the "lower surface". Of the first and second surfaces of the ceramic substrate that is the manufacturing object of the substrate manufacturing method of the embodiment, the first surface corresponds to the "upper surface" and the second surface corresponds to the "lower surface". However, these matters do not limit the direction when the manufacturing method of the substrate of the embodiment is used. In the embodiment shown below, along the X-axis, the Y-axis and the Z-axis, the object has an inclination within the range of ±10° relative to these axes. In the embodiment, orthogonality may include an error within ±10° relative to 90°.

[0056] In addition, in the specification or claims, when there are multiple structural elements and it is necessary to distinguish them from each other, sometimes "first", "second", etc. are marked before the structural elements to distinguish them. In addition, the objects to be distinguished in the specification and claims may be different from each other. Therefore, even if the claims record a structural element with the same symbol as in the present specification, the object determined by the structural element may be inconsistent in the specification and the claims.

[0057] For example, in this specification, there are structural elements marked with "1st", "2nd", and "3rd" to distinguish them, and the claims record structural elements marked with "1st" and "3rd", or in the case of recording structural elements marked with "1st" and structural elements without specific ordinal numbers in the claims, from the perspective of visibility, the structural elements can be distinguished in the claims by marking "1st" and "2nd". In this case, the structural elements marked with "1st" and "2nd" in the claims are respectively equivalent to the structural elements marked with "1st" and "3rd" or the structural elements without specific ordinal numbers in this specification. In addition, the applicable objects of this rule are not limited to structural elements, and can also be reasonably and flexibly applied to other objects.

[0058] [Implementation Method]

[0059] <Structural Example of Light Emitting Device 100 Having Substrate 2>

[0060] First, refer to Figure 1 as well as Figure 2 , the structure of the light emitting device of the substrate of the embodiment is described. Figure 1 as well as Figure 2 In the example shown, a case where a substrate made of ceramic is used in a light-emitting device is described as an example. Figure 1 It is a schematic plan view showing an example of the structure of the light emitting device 100 including the substrate 2 . Figure 2 yes Figure 1 Schematic cross-sectional view of line II-II.

[0061] like Figure 1 as well as Figure 2 As shown, the light emitting device 100 includes a plurality of light emitting units 1, a substrate 2, and a mounting substrate 3. The plurality of light emitting units 1 are respectively arranged on the surface of the substrate 2 at the +Z side. The substrate 2 is arranged on the surface of the mounting substrate 3 at the +Z side.

[0062] exist Figure 1 as well as Figure 2 In the example shown, the light emitting device 100 includes 15 light emitting units 1. The 15 light emitting units 1 include 3 light emitting units 1a, 6 light emitting units 1b, and 6 light emitting units 1c. Figure 1As shown, the shape of each of the 15 light-emitting sections 1 is roughly rectangular when viewed from above. The area of ​​the light-emitting section 1b is equal to the area of ​​the light-emitting section 1c. The area of ​​the light-emitting section 1a is larger than the area of ​​each of the light-emitting section 1b and the light-emitting section 1c. When viewed from above, the six light-emitting sections 1b are arranged along the Y direction on the -X side of the three light-emitting sections 1a. When viewed from above, the six light-emitting sections 1c are arranged along the Y direction on the +X side of the three light-emitting sections 1a. However, among the multiple light-emitting sections 1, the number and combination of the light-emitting sections 1 with different areas, the respective shapes in the top view, the arrangement in the top view, etc. can be appropriately changed.

[0063] The light emitted by the light emitting unit 1 is preferably white light, but may also be monochromatic light. The wavelength of the light emitted by the light emitting unit 1 can be appropriately selected according to the intended use of the light emitting device 100 .

[0064] like Figure 2 As shown, the light emitting unit 1 is mounted on the surface on the +Z side of the substrate 2, that is, the first surface 21, with the surface on the +Z side as the light emitting surface 11 and the surface on the opposite side of the light emitting surface 11 as the mounting surface. The light emitting unit 1 includes a light emitting element 12, a light transmissive component 13 provided on the surface on the +Z side of the light emitting element 12, and a covering component 14, and the covering component 14 covers the side surfaces of the light emitting element 12 and the side surfaces of the light transmissive component 13 except the surface on the +Z side of the light transmissive component 13. In addition, the structures of the 15 light emitting units 1 are the same.

[0065] Preferably, at least one pair of positive and negative electrodes is provided on the surface of the light emitting element 12 opposite to the light emitting surface 11. Figure 1 and Figure 2 In the example shown, the shape of the light emitting surface 11 in a plan view is substantially rectangular, but the shape of the light emitting surface 11 in a plan view may also be substantially circular or elliptical, or may be substantially triangular or hexagonal, or other polygonal shape.

[0066] The light emitting element 12 has various semiconductors such as III-V compound semiconductors and II-VI compound semiconductors. The light emitting element 12 can be an LED (Light Emitting Diode) or an LD (Laser Diode). As a semiconductor, it is preferred to use a nitride semiconductor such as InXAlYGa1-X-YN (0≤X, 0≤Y, X+Y≤1), and InN, AlN, GaN, InGaN, AlGaN, InGaAlN, etc. can also be used. From the perspective of luminous efficiency, excitation of the wavelength conversion material described later, and its mixed color relationship with luminescence, the peak wavelength of the light emitting element 12 is preferably greater than 400nm and less than 530nm, more preferably greater than 400nm and less than 490nm, and further preferably greater than 440nm and less than 475nm.

[0067] The light-transmitting component 13 is, for example, a roughly rectangular component in a plan view, and is arranged in a manner covering the upper surface of the light-emitting element 12. The light-transmitting component 13 can be formed of a light-transmitting resin material, an inorganic substance such as ceramic or glass. As a resin material, a thermosetting resin such as silicone resin, silicone-modified resin, epoxy resin, epoxy-modified resin or phenolic resin can be used. In particular, it is preferred to use a silicone resin or its modified resin with excellent light resistance and heat resistance. Moreover, the light transmittance mentioned here preferably transmits more than 60% of the light from the light-emitting element 12. In addition, the light-transmitting component 13 can also use a thermoplastic resin such as polycarbonate resin, acrylic resin, methylpentene resin, polynorbornene resin, etc. In addition, the light-transmitting component 13 can also include a light diffusing substance or a wavelength converting substance, which can convert the wavelength of at least a portion of the light from the light-emitting element 12. For example, the light-transmitting component 13 can be a structure containing a wavelength converting substance such as a resin material, ceramic, glass, or a sintered body of a wavelength converting substance. Alternatively, the light-transmitting member 13 may have a multilayer structure in which a resin layer containing a wavelength converting substance or a light diffusing substance is disposed on the ±Z side surfaces of a molded body of resin, ceramic, glass, or the like.

[0068] As the wavelength conversion material, it is possible to use yttrium-aluminum-garnet-based phosphors (e.g., (Y,Gd)3(Al,Ga)5O12:Ce), lutetium-aluminum-garnet-based phosphors (e.g., Lu3(Al,Ga)5O12:Ce), terbium-aluminum-garnet-based phosphors (e.g., Tb3(Al,Ga)5O12:Ce), CCA-based phosphors (e.g., Ca10(PO4)6Cl2:Eu), SAE-based phosphors (e.g., Sr4Al14O25:Eu), chlorosilicate-based phosphors (e.g., Ca8MgSi4O16Cl2:Eu), silicate-based phosphors (e.g., (Ba,Sr,Ca,Mg)2SiO4:Eu), β-sialon-based phosphors (e.g., (Si,Al)3(O,N)4:Eu) or α-sialon-based phosphors (e.g., Ca(Si,Al)12(O,N)16:Eu) and other oxynitride-based phosphors, LSN-based phosphors (e.g., (La,Y)3Si6N11:Ce), BSESN-based phosphors (e.g., (Ba,Sr)2Si5N8:Eu), SLA-based phosphors (e.g., SrLiAl3N4:Eu), CASN-based phosphors (e.g., CaAlSiN3:Eu) or SCASN-based phosphors (e.g., (Sr,Ca)AlSiN3:Eu) and other nitride-based phosphors, KSF-based phosphors (e.g., K2SiF6:Mn), KSAF-based phosphors (e.g., K2(Si 1-xAlx)F6-x:Mn, where x satisfies 0 < x < 1) or MGF-based phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn) and other fluoride-based phosphors, quantum dots having a perovskite structure (e.g., (Cs,FA,MA)(Pb,Sn)(F,Cl,Br,I)3, where FA and MA represent formamidine and methylammonium, respectively.), II-VI group quantum dots (e.g., CdSe), III-V group quantum dots (e.g., InP), or quantum dots having a chalcopyrite structure (e.g., (Ag,Cu)(In,Ga)(S,Se)2), etc.

[0069] In Figure 1 and Figure 2 In the example shown, the light emitting unit 1 uses a blue LED as the light emitting element 12, and a part of the wavelength of the blue light emitted by the light emitting element 12 is wavelength-converted to yellow by the wavelength conversion material contained in the light transmissive member 13, and the blue light and the yellow light are mixed (i.e., color-mixed) to emit white light. As the light diffusing material contained in the light transmissive member 13, for example, titanium oxide, barium titanate, aluminum oxide, silicon oxide, etc. can be used.

[0070] The cover member 14 is arranged to cover the side surfaces of the light emitting element 12 and the light transmissive member 13. The cover member 14 directly or indirectly covers the side surfaces of the light emitting element 12 and the light transmissive member 13. The upper surface of the light transmissive member 13 is exposed from the cover member 14 and is the light emitting surface 11 of the light emitting unit 1. Figure 1 and Figure 2 In the example shown, the covering member 14 is arranged between adjacent light-emitting sections 1, and integrally covers 15 light-emitting sections 1. In addition, the covering member 14 may be spaced between adjacent light-emitting sections among the 15 light-emitting sections 1. In order to improve the light extraction efficiency, the covering member 14 is preferably formed of a member with a high reflectivity. For example, the covering member 14 may be made of an organic material such as a resin containing a light-reflective substance such as a white pigment. In addition, the covering member 14 may be a light-reflective member composed of an inorganic material such as boron nitride or an alkali metal silicate. In this case, titanium oxide or zirconium oxide may also be contained.

[0071] As the light reflective material, titanium oxide, zinc oxide, magnesium oxide, magnesium carbonate, magnesium hydroxide, calcium carbonate, calcium hydroxide, calcium silicate, magnesium silicate, barium titanate, barium sulfate, aluminum hydroxide, aluminum oxide, zirconium oxide, silicon oxide, etc. can be cited, and it is preferred to use one of them alone or use two or more of them in combination. In addition, as the resin material in the organic material, it is preferred to use a resin material with a thermosetting resin such as epoxy resin, epoxy modified resin, silicone resin, silicone modified resin, phenolic resin as the main component as the base material. In addition, the covering member 14 can be composed of a member that is translucent or absorptive to visible light as needed.

[0072] The substrate 2 is a plate-like component having a substantially rectangular shape when viewed from above. The substrate 2 includes silicon nitride, silicon carbide, aluminum nitride, aluminum oxide, etc. When viewed from above, the shape of the substrate 2 is not limited to being substantially rectangular, but may also be substantially circular, substantially elliptical, substantially polygonal, etc.

[0073] The substrate 2 is made of a ceramic substrate 20 and has a first surface 21 and a second surface 22 located on the opposite side of the first surface 21 as described below. Figure 2 In the example shown, the substrate 2 has at least one pair of positive and negative first electrodes 24 arranged on the first surface 21 and at least one pair of positive and negative second electrodes 25 arranged on the second surface 22. In addition, a plurality of holes 23 are formed on the substrate 2, extending from the first surface 21 to the second surface 22. The holes 23 are, for example, through holes.

[0074] The substrate 2 has a first electrode 24 and a second electrode 25 corresponding to each of the 15 light-emitting portions 1. In addition, a hole 23 corresponding to each of the 15 light-emitting portions 1 is formed in the substrate 2. The first electrode 24 is electrically connected to the light-emitting element 12 via a first conductive adhesive member 26. The second electrode 25 is electrically connected to a pair of positive and negative third electrodes 31 provided on the upper surface of the mounting substrate 3 via a second conductive adhesive member 27. The first electrode 24 and the second electrode 25 are electrically connected via a conductive member 28. In the substrate 2, the first electrode 24 of the substrate 2 and the electrode of the light-emitting element 12 are connected via the first conductive adhesive member 26, so that the substrate 2 and the light-emitting portion 1 are electrically connected.

[0075] The conductive member 28 is a structure formed by sintering a conductive paste containing a conductive substance, and is arranged in the hole 23. For example, when the ceramic substrate 20 is composed of silicon nitride, the conductive paste preferably contains at least one of Ti, Hf, Zr, Nb, Ce and Mg. In addition, from the viewpoint of wettability and light reflectivity of the first conductive adhesive member 26 and the second conductive adhesive member 27, a layer of Ag, Pt, Al, Rh, Au or an alloy thereof may be provided on the surface of the conductive member 28. The structure and size of the hole 23 in which the conductive member 28 is arranged on the substrate 2 are appropriately set according to the structure and size of the first electrode 24 and the second electrode 25 of the light emitting unit 1.

[0076] The mounting substrate 3 is a plate-shaped member having a substantially rectangular shape when viewed from above. The mounting substrate 3 has wiring 32 arranged on the surface (+Z side surface and -Z side surface). The mounting substrate 3 may also have wiring 32 inside. Figure 2 In the example shown, the mounting substrate 3 includes a wiring 32 arranged inside the mounting substrate 3, a third electrode 31 provided on the +Z side surface of the mounting substrate 3 and connected to the wiring 32, and a fourth electrode 33 provided on the -Z side surface of the mounting substrate 3 and connected to the wiring 32. In the mounting substrate 3, the second electrode 25 of the substrate 2 and the third electrode 31 of the mounting substrate 3 are connected by the second conductive adhesive member 27, so that the substrate 2 and the mounting substrate 3 are electrically connected. In addition, the structure, size, etc. of the wiring 32 of the mounting substrate 3 are set according to the structure and size of the second electrode 25 in the substrate 2. In addition, the shape of the mounting substrate 3 in a plan view is not limited to a substantially rectangular shape, and may be a substantially circular shape, a substantially elliptical shape, a substantially polygonal shape, etc.

[0077] The mounting substrate 3 preferably uses an insulating material as a base material, and preferably uses a material that does not easily transmit the light emitted by the light-emitting unit 1 or external light, and preferably uses a material with a certain strength. Specifically, the mounting substrate 3 can be composed of a ceramic such as alumina, aluminum nitride, mullite, silicon nitride, phenolic resin, epoxy resin, polyimide resin, BT resin (bismaleimidetriazine resin), polyphthalamide, etc. as a base material.

[0078] <Example of a method for manufacturing a substrate according to an embodiment>

[0079] Below, refer to Figure 3 to Figure 12 , the manufacturing method of the substrate of the embodiment is described. The manufacturing method of the substrate of the embodiment, for example, is Figure 1 and Figure 2 The manufacturing method of the substrate 2 is shown.

[0080] The manufacturing method of the substrate of the embodiment includes: (a) a step of preparing a ceramic substrate 20 having a first surface 21 and a second surface 22; (b) a first processing step of ablation processing the first area in the ceramic substrate 20 by irradiating the first area of ​​the first surface 21 with a first laser having a first pulse width. In addition, the manufacturing method of the substrate of the embodiment includes (c) a second processing step of thermally processing the third area including the first area and the second area by irradiating the second laser having a second pulse width greater than the first pulse width to the second area separated from the first area of ​​either the first surface 21 or the second surface 22 in a plan view. By the manufacturing method of the substrate of the embodiment, in the second processing step, the third area and the area surrounded by the third area form a hole 23 penetrating from the first surface 21 to the second surface 22.

[0081] In the present embodiment, by performing ablation processing as a processing with minimal thermal influence in the first processing step, the portion of the ceramic substrate 20 that absorbs the irradiated first laser 51 can be removed mainly by sublimation. In the present embodiment, ablation processing refers to processing that does not produce thermal melting. As a result, the thermal influence caused by the laser can be reduced, and high-precision processing can be performed. In the present embodiment, a substrate manufacturing method is provided, which can form a hole 23 that penetrates the ceramic substrate 20 with high precision by performing high-precision processing on a desired area such as the first area by ablation processing. On the other hand, since ablation processing can reduce thermal influence, the processing time is sometimes longer than that of thermal processing. In contrast, in the present embodiment, by thermal processing in the second processing step, the area of ​​the ceramic substrate 20 that is thermally affected by the second laser 52 is mainly removed by melting, and the third area is processed more efficiently than the first processing step. As a result, the processing time of the hole 23 in the entire processing can be shortened, thereby improving the productivity of manufacturing the substrate 2. In addition, the "precision" mentioned here includes the accuracy of at least one of the position and shape. For details on the effects of the substrate manufacturing method of the embodiment, please refer to the Figure 7 to Figure 12 Provide explanation.

[0082] (a) Step of Preparing Ceramic Substrate 20

[0083] Figure 3 1 is a schematic plan view of a ceramic substrate, showing a step of preparing a ceramic substrate 20 to be manufactured by the substrate manufacturing method according to the embodiment. Figure 4 yes Figure 3 Schematic cross-sectional view of line IV-IV.

[0084] exist Figure 3 and Figure 4 In the example shown, the ceramic substrate 20 prepared in the process is a plate-shaped member having a first surface 21 and a second surface 22 located on the opposite side of the first surface 21, and in a state where the hole 23, the first electrode 24, the second electrode 25, etc. are not provided. The first surface 21 and the second surface 22 of the ceramic substrate 20 are consistent with the first surface 21 and the second surface 22 of the substrate 2 described above. In addition, the ceramic substrate 20 may also include wiring on the first surface 21, the second surface, and at least a part of the interior. If the thickness of the ceramic substrate 20 is too thick, it may be difficult to form the hole 23. Therefore, the thickness of the ceramic substrate 20 is preferably not less than 100 μm and not more than 500 μm.

[0085] (b) First processing step of ablating the first region

[0086] Figure 5 This is a schematic plan view of a ceramic substrate showing a first processing step in the method for manufacturing a substrate according to the embodiment. Figure 6 yes Figure 5Schematic cross-sectional view along line VI-VI.

[0087] like Figure 5 and Figure 6 As shown, in the above step, the first region 201 of the first surface 21 is irradiated with the first laser beam 51 having a first pulse width, thereby ablation processing is performed on the first region 201 of the ceramic substrate 20. Figure 5 and Figure 6 In the example shown, the first region 201 is a linear, substantially rectangular region with the long side in the Y direction and continuously formed in a plan view. In addition, the first region 201 is a bottomed hole extending from the first surface 21 to the second surface 22 in the Z direction but not penetrating. The first region 201 includes not only the region in the XY plane but also the region in the Z direction. In the substrate manufacturing method of the embodiment, the first region 201 can be ablated by irradiating the first surface 21 of the ceramic substrate 20 with the first laser 51 while changing the relative position between the irradiation position of the first laser 51 and the ceramic substrate 20.

[0088] The shape of the first region 201 when viewed from above is not limited to a roughly rectangular shape. For example, in the first processing step, the shape of the first region 201 when viewed from above can be a roughly circular, roughly semicircular, roughly fan-shaped, roughly elliptical, roughly semi-elliptical, etc., annular with an outer edge containing straight lines and arc lines, or a polygonal ring such as a roughly square or roughly polygonal (hereinafter, may also be referred to as an annular region). The annular region can be formed in any manner of continuity or discontinuity. In the first processing step, the first region 201 that has been ablated includes a portion that is mainly removed by sublimation, and a portion that is deteriorated around it or in the depth direction. The deteriorated portion includes a plurality of microcracks. During the ablation process, since the removed portion is generated, the ceramic will undergo a sharp volume change and residual stress associated with the volume change. Microcracks are phenomena caused by these mechanical changes. The portion that is mainly removed by sublimation does not reach the second surface in the Z direction. In the Z direction, the deteriorated portion of the ceramic substrate 20 can reach the second surface 22 from the first surface 21. By making the first region 201 extend from the first surface 21 to the second surface 22 , a smooth inner surface from the first surface 21 to the second surface 22 can be formed in the hole 23 .

[0089] Compared with thermal processing, ablation processing can achieve high-precision processing. On the other hand, compared with thermal processing, processing may take time. Therefore, in the hole 23, it is preferable to form the first region 201 by ablation processing in a portion that particularly requires high precision.

[0090] In the ablation process using the first laser beam 51 , the first pulse width of the first laser beam 51 may be in either the femtosecond region or the picosecond region.

[0091] The light source for emitting the first laser beam 51 may be a fiber laser, a titanium sapphire laser, or the like. From the viewpoint of improving processing accuracy, the first pulse width of the first laser beam 51 is preferably in the femtosecond region, more preferably 1 femtosecond or more and 10 picoseconds or less.

[0092] exist Figure 5 and Figure 6 In the example shown, the maximum width of the first region 201 in the X direction is approximately 20 μm. In the first region 201, the surface of the ceramic irradiated by the first laser 51 is removed. The first region 201 can be irradiated with the first laser 51 once to remove the ceramic, or irradiated with the first laser 51 multiple times to gradually remove the ceramic. Figure 6 In the example shown, the ceramic substrate 20 has a V-shaped recessed portion having a depth of approximately 30 μm or more and approximately 50 μm or less in the Z direction, where the ceramic is removed, in the first region 201. Since the ablation process is performed in the first region 201, thermal melting of the ceramic does not occur, and for example, the processing width in the X direction is smaller than that of the thermal process described later. In addition, around the first region 201, the width of the region where the ceramic substrate 20 is degraded by the ablation process is also reduced by approximately 1 / 10 compared with the process involving thermal melting.

[0093] exist Figure 5 and Figure 6 In the example shown, a deteriorated region 201a is formed on the -Z side of the first region 201, that is, on the side of the ceramic substrate 20 opposite to the side irradiated with the first laser 51. The deteriorated region 201a indicates a region of the ceramic substrate 20 that is deteriorated by irradiation with the first laser 51. The deteriorated region 201a extends from the lower end of the V-shaped recessed portion of the first region 201 toward the -Z side and reaches the surface of the -Z side of the ceramic substrate 20. Deterioration refers to a state in which the strength of the material is reduced by 30% or more and 50% or less than the original value.

[0094] (c) A second processing step of irradiating the second region with a second laser to perform thermal processing on the third region

[0095] Figure 7 1 is a first schematic plan view of the ceramic substrate 20 showing the second processing step of the substrate manufacturing method according to the embodiment. Figure 8 yes Figure 7 1 is a schematic cross-sectional view of line VIII-VIII. Fig. 9 1 is a second schematic plan view of the ceramic substrate 20 showing the second processing step in the substrate manufacturing method according to the embodiment. Fig.10 yes Fig. 9 The second schematic cross-sectional view along line XX. Fig.11A It is a schematic plan view showing a hole formed by the substrate manufacturing method according to the embodiment. Fig. 11BIt is a schematic bottom view showing a hole formed by the substrate manufacturing method according to the embodiment. Fig.12 yes Fig.11A Schematic cross-sectional view along line XII-XII.

[0096] In the second processing step, the second laser 52 having a second pulse width greater than the first pulse width is irradiated onto the second region 202 separated from the first region 201 of either the first surface 21 or the second surface 22 in a plan view, and the third region 203 including the first region 201 and the second region 202 is heated. In the present embodiment, the wave that makes the pulse width of the second pulse width the maximum in the pulse repetition period is a continuous wave, and the second pulse width includes a continuous wave. Fig.11A , Fig. 11B and Fig.12 As shown, in the second processing step, the third region 203 and the fourth region 204 surrounded by the third region 203 form the hole 23 penetrating from the first surface 21 to the second surface 22. In addition, when the area surrounded by the second region 202 is small, the area surrounded by the second region 202 may be composed only of the third region 203. In this case, only the third region 203 is removed, and the hole 23 penetrating from the first surface 21 to the second surface 22 can be formed.

[0097] In this embodiment, the case where the second laser beam 52 is irradiated from the second surface 22 side is described. Figure 7 to Figure 10 As shown in FIG. 2 , in the second processing step, the second laser beam 52 is irradiated onto the second region 202 from the second surface 22 side. Figure 7 and Figure 8 In the example shown, the second laser 52 is irradiated onto the second region 202 separated from the first region 201 in the second surface 22 in a plan view. That is, the second region 202 is located on the second surface 22. In addition, the second region 202 is a roughly semi-elliptical annular region in a plan view, in which an ellipse with the X direction as the major axis is cut into approximately half in the major axis direction. The second region 202 includes not only the region in the XY plane but also the region in the Z direction. In the substrate manufacturing method of the embodiment, the second laser 52 can be irradiated onto the second surface 22 of the ceramic substrate 20 while changing the relative position of the irradiation position of the second laser 52 and the ceramic substrate 20.

[0098] In the ceramic substrate 20 irradiated with the second laser beam 52 , the heat generated by the irradiation with the second laser beam 52 diffuses not only in the second region 202 but also from the second region 202 to the periphery.

[0099] In the second region 202, ceramics are removed mainly by melting. Figure 7 to Figure 10In the example shown, the width of the second region 202 in the X direction is approximately 50 μm or more and approximately 60 μm or less. In the second region 202, the ceramic is gradually removed by irradiating the second laser 52 multiple times. In the second region 202, the ceramic can also be removed at once by irradiating the second laser 52 once.

[0100] On the other hand, around the second region 202 not irradiated with the second laser beam 52, the ceramic substrate 20 is degraded by heat (hereinafter sometimes referred to as thermal degradation). Fig. 9 as well as Fig.10 In the example shown, the third region 203 is a region around the second region 202 that is not irradiated with the second laser 52, and is also a region where the ceramic substrate 20 undergoes thermal degradation. In the third region 203, the ceramic substrate 20 deteriorates due to heat, and the mechanical strength decreases and becomes brittle. The mechanical strength of the third region 203 gradually decreases as it approaches the second region 202. Fig. 9 and Fig.10 In the example shown, the thermally altered third region 203 is indicated by dotted hatching, and the higher the density of the dots (the smaller the interval between adjacent dots), the lower the mechanical strength. In this specification, the thermal processing of the ceramic substrate 20 includes mainly removing the ceramic by melting in the region irradiated with the second laser 52, and thermally altering the ceramic around the region irradiated with the second laser 52.

[0101] In the second processing step, the area around the fourth area 204 surrounded by the third area 203 whose mechanical strength is reduced in the ceramic substrate 20 becomes separable from the outside of the third area 203 (the area where the mechanical strength is not reduced). Then, by applying slight vibration or impact, such as lifting the ceramic substrate 20, a substrate 2 can be obtained in which the area surrounded by the third area 203 is removed. In addition, the separated area may include a part of the third area 203. Fig. 9 and Fig.10 In the example shown, the fourth area 204 is completely surrounded by the third area 203. As a result, Fig.11A , Fig. 11B and Fig.12 As shown in FIG. 2 , the fourth region 204 forms a hole 23 that penetrates from the first surface 21 to the second surface 22. Fig.11A , 11B In the example shown in Figures 1 and 12, the shape of the hole 23 in a plan view is approximately semi-elliptical.

[0102] Since the mechanical strength in the third region 203 is not uniform, when the area around the fourth region 204 is separated from the outside of the third region 203 (the area where the mechanical strength is not reduced), the end position of the area around the separated fourth region 204 deviates. Due to the deviation in the end position of the area around the fourth region 204, the inner side surface of the hole 23 becomes rough. Fig.12 In the example shown, the inner surface of the hole 23 is roughened except for the area where the V-shaped recess is formed in the first area 201, forming a rough surface area 202a and a rough surface area 202c. In the rough surface area 202a, the smoothness accuracy of the inner surface of the hole 23 is lower than that of the rough surface area 202c.

[0103] In the present embodiment, the area where the first region 201 is formed on the inner side surface of the hole 23 is less affected by the deviation of the end position of the separated fourth region 204. In addition, as described above, the area of ​​the ceramic substrate 20 that is deteriorated around the first region 201 is smaller than the area around the second region 202. Therefore, a smooth surface can be obtained in the smooth area 202b corresponding to the V-shaped recess in the first region 201 on the inner side surface of the hole 23. In the smooth area 202b, the smoothness accuracy of the inner side surface of the hole 23 is improved. In addition, the surface roughness of the rough surface area 202c in the first region 201 can also be reduced. Fig.11A In the example shown, the outline of the hole 23 observed from the first surface 21 is a substantially straight line close to the designed straight line shape in the area where the first area 201 is formed, which is a high-precision process. In the area where the second area 202 is formed, the shape is relatively close to the designed semi-elliptical shape. Although it is a semi-elliptical shape as a whole, it contains a plurality of bends and curved lines, which is a shape that cannot be called a high-precision process. Fig. 11B In the example shown, the outline of the hole 23 observed from the second surface 22 is close to the designed straight line shape in the area where the first area 201 is formed, and is a relatively high-precision processed shape. Fig.11A Similarly, the shape is relatively close to the designed semi-elliptical shape. Although the overall shape is semi-elliptical, it contains multiple bends and curved lines, and is a shape that can hardly be called high-precision processing.

[0104] In addition, Fig.11A as well as Fig.12 In the example shown, the area of ​​the first region 201 subjected to the ablation process is smaller than the areas of the second region 202 and the third region 203 subjected to the hot processing. Therefore, the processing time is shorter than when the entire annular region of the hole 23 is subjected to the ablation process.

[0105] Therefore, in the method for manufacturing the substrate of the embodiment, the hole 23 can be formed in a short time and the accuracy of the hole 23 can be improved in a desired area such as the smooth area 202b, compared with the case where the entire annular area of ​​the hole 23 is ablated. In addition, the position, size, number, etc. of the smooth area 202b of the hole 23 can be appropriately changed according to the position where the conductive member 28 is to be formed. The smaller the size of the smooth area 202b of the hole 23 is, or the fewer the number of the smooth areas 202b is, the shorter the processing time of the hole 23 can be.

[0106] In addition, in the manufacturing method of the substrate of the embodiment, in the second processing step, the second region 202 is annular. Therefore, the third region 203 and the fourth region 204 can form the hole 23 penetrating from the first surface 21 to the second surface 22, and the hole 23 can be formed more efficiently than when the second laser 52 is irradiated on both the second region 202 and the fourth region 204.

[0107] The shape of the second region 202 in a top view is not limited to an approximate semi-ellipse. For example, in the second processing step, the shape of the second region 202 in a top view can be a ring whose outer edge includes straight lines and arcs, such as a roughly circular, roughly semi-circular, roughly fan-shaped, roughly elliptical, or a polygonal ring (hereinafter also referred to as an annular region) such as a roughly square, roughly rectangular, or roughly polygonal. In the annular region, the third region 203 can be continuous, and the second region 202 can be either continuous or discontinuous. In the third region 203, in the Z direction, if the thermal deterioration of the ceramic substrate 20 runs from the first surface 21 to the second surface 22, then in the second region 202, the thermal deterioration of the ceramic substrate 20 does not necessarily have to run from the first surface 21 to the second surface 22. Since the third region 203 is a region extending from the second region 202 to the periphery, the inner and outer sides of the annular shape in the top view of the second region 202 have similar shapes.

[0108] Thermal processing using the second laser beam 52 can be performed by setting the second pulse width of the second laser beam 52 to be larger than the first pulse width, that is, to a nanosecond region or longer.

[0109] A CO2 laser light source or the like can be used as a light source for emitting the second laser light 52. In the present embodiment, the second laser light 52 is a laser light emitted from a CO2 laser light source. From the viewpoint of improving processing efficiency, the second pulse width of the second laser light 52 is preferably 700 nanoseconds or more and 70 microseconds or less.

[0110] The method for manufacturing the substrate of the embodiment may further include a conductive member forming step of placing a conductive paste in the hole 23 and firing the conductive paste to form a conductive member. Figure 2The conductive member 28 is shown. In the method for manufacturing the substrate of the embodiment, by including the conductive member forming step, the light emitting element or various electrical elements arranged on the substrate 2 can be electrically connected to the substrate 2.

[0111] For example, when the ceramic substrate 20 is composed of silicon nitride, the conductive paste preferably includes at least one of Ti, Hf, Zr, Nb, Ce and Mg. When the conductive paste is sintered, a nitrogen compound containing at least one of Ti, Hf, Zr, Nb, Ce and Mg is formed on the interface between the conductive component 28 and the inner side surface of the hole 23, which can improve the adhesion between the conductive component 28 and the inner side surface of the hole 23. On the other hand, when the ceramic substrate 20 is composed of aluminum nitride, when laser is irradiated to form the hole 23 on the ceramic substrate 20, aluminum may be precipitated on the irradiated surface. Therefore, when the ceramic substrate 20 is made of aluminum nitride and a conductive paste containing at least one of Ti, Hf, Zr, Nb, Ce and Mg is used as the material of the conductive member 28, by sintering the conductive paste after removing the precipitated aluminum, a nitrogen compound containing at least one of Ti, Hf, Zr, Nb, Ce and Mg is formed on the interface between the conductive member 28 and the inner side surface of the hole 23, thereby improving the adhesion between the conductive member 28 and the inner side surface of the hole 23. In addition, the heat conducted from the conductive member 28 through the inner side surface of the hole 23 to the ceramic included in the substrate 2 can be efficiently released.

[0112] <Modification>

[0113] The following is a description of a method for manufacturing a substrate according to a modified example. In addition, the same names and symbols as those in the above-described embodiment represent the same or homogeneous components, and detailed descriptions thereof are appropriately omitted. This is also the case in the following embodiments.

[0114] (Variant 1)

[0115] The modification 1 is different from the above-described embodiment in that the second laser beam 52 is irradiated onto the first surface 21 in the second processing step.

[0116] Fig.13 1 is a schematic plan view of a ceramic substrate 20 showing a second processing step in the method for manufacturing a substrate according to Modification 1. FIG. Fig.14 yes Fig.13 A schematic cross-sectional view of the XIV-XIV line of FIG. Fig.14 In the cross-sectional diagram, for the sake of convenience, the Fig.13 The third region 203 is represented by the same hatching as in the top view.

[0117] like Fig.13 as well as Fig.14As shown in FIG. 2 , in this modification, the second region 202 isolated from the first region 201 in the first surface 21 is irradiated with the second laser beam 52. Fig.13 as well as Fig.14 In the example shown, the second region 202 is a roughly semi-elliptical annular region obtained by cutting an ellipse with the X direction as the major axis into approximately half along the major axis direction when viewed from above. In addition, the second region 202 extends from the first surface 21 to the second surface 22 in the Z direction. The second region 202 includes not only the region in the XY plane but also the region in the Z direction. In addition, in the Z direction, if the third region 203 extends from the first surface 21 to the second surface 22, the second region 202 can penetrate from the first surface 21 to the second surface 22.

[0118] As described in this modification, when the second area 202 of the first surface 21 is irradiated with the second laser 52, the laser of the second laser 52 advances from the first surface 21 to the second surface 22. The processing energy of the laser decreases in the advancing direction, so the opening diameter on the second surface 22 of the hole 23 is smaller than the opening diameter on the first surface 21 of the hole 23. However, in this modification, the same effect as the above-described embodiment can be obtained. That is, the hole 23 including the contour processed with high precision can be obtained on the first surface 21.

[0119] (Variant 2)

[0120] In the modification 2, the main difference from the above-described embodiment is that the first region 201, the second region 202, the third region 203, and the hole 23 are substantially rectangular in shape in a plan view.

[0121] Fig.15 1 is a schematic plan view of the ceramic substrate 20 showing the first region 201 in the substrate manufacturing method according to Modification Example 2. Fig.16 yes Fig.15 Schematic cross-sectional view along line XVI-XVI of FIG.

[0122] exist Fig.15 as well as Fig.16In the example shown, the first region 201 is a substantially rectangular annular region formed continuously in a plan view. In addition, the first region 201 is a bottomed hole that does not penetrate from the first surface 21 to the second surface 22 in the Z direction. The first region 201 includes not only the region in the XY plane but also the region in the Z direction. In the manufacturing method of the substrate of this modified example, by changing the relative position between the irradiation position of the first laser 51 and the ceramic substrate 20, the first surface 21 of the ceramic substrate 20 is irradiated with the first laser 51, so that the first region 201 can be ablated. In addition, the first region 201 can be a substantially rectangular annular region formed intermittently in a plan view, and the first region 201 is isolated and formed at the four corners of the substantially rectangular shape. By forming the first region 201 intermittently, the processing time can be shortened.

[0123] In the manufacturing method of the substrate of the present embodiment, in the first processing step, since the first region 201 is annular, the entire outer edge of the hole 23, that is, the end face of the hole 23 can be formed with high precision by ablation processing. In addition, in the manufacturing method of the substrate of the present embodiment, the shape of the first region 201 is rectangular in a plan view, so the hole 23 having a rectangular shape in a plan view can be formed.

[0124] Fig.17 1 is a first schematic plan view of the ceramic substrate 20 showing the second region 202 and the third region 203 in the method for manufacturing the substrate according to Modification 2. Fig.18 yes Fig.17 1 is a schematic cross-sectional view of line XVIII-XVIII. Fig.19 1 is a second schematic plan view of the ceramic substrate 20 showing the second region 202 and the third region 203 in the method for manufacturing the substrate according to Modification 2. Fig. 20 yes Fig.19 The second schematic cross-sectional view along line XX-XX. Fig.21A 1 is a schematic plan view of a substrate showing a hole 23 formed by the method for manufacturing a substrate according to Modification 2. Fig.21B This is a schematic bottom view of a substrate showing holes formed by the substrate manufacturing method according to Modification Example 2. Fig.22A yes Fig.21A In addition, for the sake of convenience, Fig. 20 In the cross-sectional diagram, the Fig.19 The same hatching as in the top view represents the third region 203 . Fig. 22B : is a schematic cross-sectional view showing the structure of a light-emitting device 200 including a substrate according to Modification Example 2.

[0125] exist Fig.17 as well as Fig.18In the example shown, the second region 202 is a roughly rectangular annular region in a plan view. In addition, the second region 202 is located on the inner side of the first region 201. In addition, the second region 202 penetrates from the first surface 21 to the second surface 22 in the Z direction. The second region 202 includes not only the region within the XY plane, but also the region in the Z direction. In the method for manufacturing a substrate of the embodiment, by changing the irradiation position of the second laser 52 and the relative position of the ceramic substrate 20, the second surface 22 of the ceramic substrate 20 is irradiated with the second laser 52, so that the second region 202 can be thermally processed. Fig.22A In the example shown, a smooth region 202b is obtained on the +Z side of both sides (e.g., +X side and -X side) of the inner side of the hole 23. In addition, a rough surface region 202c with reduced surface roughness is obtained on the -Z side of both sides of the inner side of the hole 23.

[0126] By heat-processing the second region 202 and the third region 203, the region surrounded by the first region 201 in the ceramic substrate 20 can be separated from its surrounding region. Then, by slightly vibrating or impacting the ceramic substrate 20 such as lifting it up, the substrate 2 from which the region surrounded by the first region 201 is removed can be obtained. Fig.21A , 21B As shown in FIG. 22A, a hole 23 is formed that passes through the first surface 21 to the second surface 22. Furthermore, when the area surrounded by the second region 202 is small, the area surrounded by the second region 202 can be composed only of the third region 203. In this case, only the third region 203 needs to be removed. Fig.21A , 21B In the example shown in FIG. 22A , the shape of the hole 23 when viewed from above is substantially rectangular. Fig.21A In the example shown, the outline of the hole 23 observed from the first surface 21 is a rectangle containing a substantially straight line close to the designed rectangle in the area where the first area 201 is formed, which is a high-precision process. Fig.21B In the example shown, the outline of the hole 23 viewed from the second surface 22 is a line close to the designed rectangle in the region where the first region 201 is formed, which is a relatively high-precision process.

[0127] Here, since the second pulse width of the second laser is larger than the first pulse width of the first laser, the second region 202 irradiated with the second laser expands more than the first region 201 irradiated with the first laser. Thus, in this modification, since the second region 202 is located inside the first region 201 in the second processing step, the end position of the second region 202 expanding from the inside to the outside can be aligned with the end position of the first region 201 located outside the second region 202. Thus, for example, by using the end position of the first region 201 as the end face of the hole 23, the end face of the hole 23 can be formed with high precision. For example, as Fig. 22B As shown, when the conductive member 28 is arranged in the hole 23 formed with high precision at the end surface as wiring, a light emitting device 200 can be obtained in which the mounting precision of the light emitting portion 1 mounted on the first surface 21 side of the hole 23 is improved. The effects of this modification example other than those described above are the same as those of the above embodiment.

[0128] [Example]

[0129] Hereinafter, a light reflectance comparison experiment between a ceramic substrate and glass, Example 1, Example 2, a reference example, and a comparative example will be described. However, the present invention is not limited to these examples.

[0130] First, an experiment was conducted to confirm the difference in reflectivity between a ceramic substrate and glass. The ceramic substrate used in this experiment was silicon nitride with a thickness of 0.32 mm. In addition, the thickness of the glass was 5 mm, and it contained silicate (SiO2), soda ash (Na2O), and lime (CaO) as main components. In this experiment, the ceramic substrate had a first surface and a second surface located on the opposite side of the first surface. The first surface of the ceramic substrate corresponds to the "upper surface." The second surface of the ceramic substrate corresponds to the "lower surface." In addition, the glass includes a first surface and a second surface located on the opposite side of the first surface. The first surface of the glass corresponds to the "upper surface." The second surface of the glass corresponds to the "lower surface." The reflectivity of the ceramic substrate and the glass was measured using SpectraMagic (manufactured by Konica Minolta, Inc.) focused on each first surface, and the reflectivity of lasers with a wavelength of 360 nm or more and 740 nm or less was measured. The results are as follows. Fig.23A shown.

[0131] like Fig.23AAs shown, the light transmittance of the glass is approximately 10% in the range of 360 nm to 680 nm, and approximately 26% in the range of 680 nm to 740 nm, both of which are low values. On the other hand, the light reflectivity of the ceramic substrate is above 30% at all wavelengths. This result indicates that the light reflectivity of the ceramic substrate is higher than that of the glass. That is, the light transmittance of the ceramic substrate is lower than that of the glass. Therefore, it is considered that it is difficult to focus the laser on a specific position inside the ceramic substrate in the ceramic substrate. Therefore, as described in the above embodiment, the method of focusing the first laser and the second laser on the first surface or the second surface for irradiation can be said to have good utilization efficiency in the laser processing of the ceramic substrate.

[0132] Table 1 shows the main specifications of the first laser 51 and the second laser 52 used in the manufacturing methods of the substrates of Example 1, Example 2, Reference Example and Comparative Example. The ceramic substrate used in the manufacturing methods of the substrates of Example 1, Example 2, Reference Example and Comparative Example is silicon nitride with a thickness of 150 μm.

[0133] [Table 1]

[0134]

[0135] In Example 1, 50 holes 23 were formed by combining the first laser 51 and the second laser 52 by the manufacturing method of the substrate of the embodiment described above. Specifically, after the first laser 51 was irradiated onto the first surface 21 of the ceramic substrate 20 to ablate the first region 201, the second laser 52 was irradiated onto the second surface 22 of the ceramic substrate 20 to heat-process the third region 203 including the first region 201 and the second region 202. Thus, the third region 203 and the fourth region 204 surrounded by the third region 203 were separated from the ceramic substrate 20. The third region 203 and the fourth region 204 surrounded by the third region 203 formed the hole 23 penetrating from the first surface 21 to the second surface 22.

[0136] In Example 2, 50 holes 23 are formed by combining the first laser 51 and the second laser 52 through the manufacturing method of the substrate of the above-mentioned modification example 1. Specifically, after the first laser 51 is irradiated onto the first surface 21 of the ceramic substrate 20 to ablate the first region 201, the second laser 52 is irradiated onto the first surface 21 of the ceramic substrate 20 to heat-process the third region 203 including the first region 201 and the second region 202. Thus, the third region 203 and the fourth region 204 surrounded by the third region 203 can be separated from the ceramic substrate 20. The third region 203 and the fourth region 204 surrounded by the third region 203 form a hole 23 that penetrates from the first surface 21 to the second surface 22.

[0137] In the reference example, 50 holes 23 are formed using only the first laser 51. Specifically, the first surface 21 of the ceramic substrate 20 is irradiated with the first laser 51 to perform ablation processing so that an annular region corresponding to the outer edge of the hole 23 penetrates from the first surface 21 to the second surface 22, thereby separating the area surrounded by the annular region from the ceramic substrate 20. The hole 23 is formed by the annular region and the area surrounded by the annular region.

[0138] In the comparative example, 50 holes 23 were formed using only the second laser 52. Specifically, the second laser 52 was irradiated on the first surface 21 of the ceramic substrate 20 to perform thermal processing so that the annular region corresponding to the outer edge of the hole 23 penetrated from the first surface 21 to the second surface 22, thereby separating the area surrounded by the annular region from the ceramic substrate 20. The hole 23 is formed by the annular region and the area surrounded by the annular region.

[0139] <Result of Formation of Hole 23>

[0140] Reference Figure 23B to Figure 30 , the results of forming the holes 23 by the substrate manufacturing methods of Example 1, Example 2, Reference Example and Comparative Example are described. Fig. 23B as well as Fig.24 This is a photograph of the hole 23 formed by the method for manufacturing a substrate in Example 1. Fig. 23B This is a top view of the hole 23 , which shows the first surface 21 . Fig.24 This is a bottom view of the hole 23 , which shows the second surface 22 . Fig.25 as well as Fig.26 This is a photograph of the hole 23 formed by the method for manufacturing a substrate in Example 2. Fig.25 This is a bird's-eye view of hole 23. Fig.26 This is a photo of Kong 23 looking up. Fig. 27 as well as Fig.28 This is a photograph of the hole 23 formed by the substrate manufacturing method of the reference example. Fig. 27 This is a bird's-eye view of hole 23. Fig.28 This is a photo of Kong 23 looking up. Fig.29 as well as Fig.30 This is a photograph of the hole 23 formed by the method for manufacturing a substrate of a comparative example. Fig.29 This is a bird's-eye view of hole 23. Fig.30 This is a photo of Kong 23 looking up. Figure 23B to Figure 30 Each of them shows an image obtained by photographing the hole 23 formed in the ceramic substrate 20 using a camera.

[0141] exist Figure 23B to Figure 30In each example, six holes 23 out of 50 holes 23 formed by the manufacturing method of the substrate of each of Example 1, Example 2, Reference Example and Comparative Example are shown. Figure 23B to Figure 28 As shown, in Example 1, Example 2 and Reference Example, a clear outline of the hole 23 is formed. In particular, the outline of the hole 23 on the first surface 21 ablated by the first laser 51 is clearer. More specifically, the straight portion of the hole 23 in the first surface 21 is formed with excellent linearity. In addition, the corner of the hole 23 in the first surface 21 is formed to be approximately right angles. On the other hand, in the comparative example, the straight portion of the hole 23 is curved, and the linearity is poorer than that of Example 1, Example 2 and Reference Example. In addition, the corner of the hole 23 is formed as a curved surface.

[0142] Table 2 below shows a list of evaluations of the formation results of the plurality of holes 23 in each example.

[0143] [Table 2]

[0144]

[0145] In the evaluation of Table 2, a plurality of holes 23 including holes having a substantially circular shape and a substantially rectangular shape in a plan view were formed by the substrate manufacturing methods of each of Example 1, Example 2, Reference Example, and Comparative Example. The size of the hole 23 in a plan view was set to be 0.1 mm or more and 0.4 mm or less in the case of the substantially rectangular hole, and to be 0.06 mm or more and 0.3 mm or less in the case of the substantially circular hole. The number of the plurality of holes 23 was set to 50.

[0146] In the evaluation results of Table 2, "◎" indicates an excellent level. "○" indicates a level that can be used as a substrate. "×" indicates a level that cannot be used as a substrate. In addition, these marking methods in the evaluation results are also the same in the following evaluation results.

[0147] In the evaluation items of Table 2, "corner shape" indicates the shape of the corner of the hole 23, and the closer to a right angle, the better. "Straight line shape" indicates the shape of the straight line of the hole 23, and the better the linearity, the better. The evaluation of "corner shape" and "straight line shape" is performed by visually judging the results by observing the appearance using a microscope. "Difference in front and back dimensions" indicates the difference between the dimension of the first surface 21 (front) side and the dimension of the second surface 22 (back) side of the hole 23. "Difference in front and back dimensions" is expressed by the ratio of the error to the design value of the dimension, a positive value indicates that it is larger than the design value, and a negative value indicates that it is smaller than the design value. "Processing time" indicates the total time required to form multiple holes 23.

[0148] As shown in Table 2, in the reference example, good results were obtained in the evaluation items of corner shape, linear shape, front and back dimensional difference, and substrate damage. On the other hand, the processing time was 14.0 seconds, which was longer than that of the other examples. It can be seen from this that the reference example can accurately form a plurality of holes 23, and can be used, for example, in a case where there is no restriction on the processing time.

[0149] In the comparative example, the processing time is 1.2 seconds, which is shorter than that of the other examples. On the other hand, the evaluation items of the corner shape, the straight portion shape, the internal and external dimension difference, and the substrate damage have reached a level that cannot be used as a substrate. Specifically, the radius of curvature of the corner is approximately 25μm. In addition, the maximum winding width of the straight portion is 12μm. It can be seen that in the comparative example, a plurality of holes 23 can be formed with excellent productivity, but at the same time, the formation accuracy of the plurality of holes 23 is lower than that of the other examples. Here, the level that cannot be used as a substrate refers to a situation where, assuming that a conductive component is arranged in a hole formed on the substrate and a light-emitting element is installed on the hole, there is a high possibility that the light-emitting element deviates from the predetermined installation position.

[0150] In Example 1 and Example 2, good results were obtained in the evaluation items of corner shape, straight shape, front and back dimensional difference, and substrate damage. In addition, the processing time was 3.8 seconds, which was approximately 1 / 4 of that in the reference example and close to that in the comparative example. It can be seen from this that in Example 1 and Example 2, a plurality of holes 23 can be formed with high precision and with excellent productivity. In other words, it can be seen that in Example 1 and Example 2, both high precision and excellent productivity can be taken into account when forming the holes 23.

[0151] <Result Example of Formation of Holes 23 by the Substrate Manufacturing Method of Example 1>

[0152] The formation result of the hole 23 in the substrate manufacturing method of Example 1 is described in more detail.

[0153] First, refer to Fig.31 as well as Fig.32 The influence of the interval between the first region 201 and the second region 202 on the formation accuracy of the hole 23 is described with reference to samples 1 to 5.

[0154] Fig.31 It is a schematic diagram for explaining the interval between the first area 201 and the second area 202 . Fig.31 The surface ( Figure 4 The first laser beam 51 on the first surface 21 shown in the figure and the first laser beam 51 on the -Z side surface ( Figure 42. The first laser 51 and the second laser 52 respectively represent the diameters of the laser beams irradiated onto the ceramic substrate 20. The laser beam diameter of the first laser 51 is 15 μm. The beam spot diameter of the second laser 52 is 50 μm.

[0155] exist Fig.31 , the first moving axis C1 represents the moving trajectory of the center of the laser of the first laser 51 as it moves relative to the ceramic substrate 20. The second moving axis C2 represents the moving trajectory of the center of the second laser 52 as it moves relative to the ceramic substrate 20. The interval Δ is the interval between the first moving axis C1 and the second moving axis C2. The interval Δ corresponds to the distance between the first area formed by the first laser 51 and the second area formed by the second laser 52. In addition, the interval Δ corresponds to the third area 203. The interval Δ may also be the shortest distance between the center of the first area and the center of the second area. In the manufacturing method of the substrate of the embodiment, a plurality of holes 23 can be formed, and the center distance between adjacent holes 23 is set to be greater than 100 μm and less than 500 μm.

[0156] exist Fig.31 , the first end face E1 indicates the end face subjected to ablation processing by the first laser 51. The second end face E2 indicates the end face subjected to thermal processing by the second laser 52. In the thermal processing using the second laser 52, the processing area is expanded due to heat, compared with the ablation processing using the first laser 51. Therefore, the second distance d2 between the second moving axis C2 and the second end face E2 is greater than the first distance d1 between the first moving axis C1 and the first end face E1.

[0157] Fig.32 2 is a graph showing the relationship between the interval Δ between the first region 201 and the second region 202 and the formation position deviation. Fig.32 As shown in FIG. 1 , the first laser beam 51 and the second laser beam 52 are irradiated with different intervals Δ from each other. The “photographic image of the first surface” is an image taken from the first surface 21 side of the hole 23 formed on the ceramic substrate 20 with the interval Δ of each sample. The “formation position deviation” indicates the maximum value of the deviation of the end surface position of the hole 23 formed on the ceramic substrate 20 with the interval Δ of each sample from the design position of the hole 23, that is, the maximum error in the formation of the end surface of the hole 23.

[0158] like Fig.32As shown in FIG. 1 , in the ceramic substrate 20, when the interval Δ is in the range of 25.0 μm to 32.5 μm, the position deviation is +5.0 μm or less, which is evaluated as "◎" or "○". It can be seen from this that from the viewpoint of forming the hole 23 with high precision, the interval Δ is preferably 25.0 μm to 32.5 μm, more preferably 30.0 μm to 32.5 μm, and particularly preferably 32.5 μm.

[0159] Fig.33 The following are photographs of the ceramic substrate 20 after the first processing step, taken from the first surface 21 side and the second surface 22 side in the substrate manufacturing method of Example 1. Fig.33 In the method for manufacturing a substrate of Example 1, a photograph taken from the first surface 21 side and a photograph taken from the second surface 22 side are shown for the hole 23 formed after the second processing step. Fig.33 In the example shown, Fig.31 The spacing Δ shown is 32.5 μm.

[0160] like Fig.33 As shown, in the first processing step, the first region 201 is formed on the first surface 21 by ablation processing. According to the photograph of the second surface 22 of the ceramic substrate 20 taken after the first processing step, it can be seen that the deterioration of the ceramic substrate caused by the ablation processing of the first surface 21 also affects the second surface 22. However, in the state after the first processing step, the area surrounded by the first region 201 is not separated from its surrounding area.

[0161] In the second processing step, the hole 23 is formed in the ceramic substrate 20 by heat processing. Fig.33 In the example shown, thermal processing is performed by irradiating the second laser from the second surface 22 side. Fig.33 As shown in the full-focus image of the hole 23 in the 2nd surface 22 and the photographic image of the hole 23 from the oblique direction, the end surface of the hole 23 in the 2nd surface 22 has larger concavities and convexities than the end surface of the hole 23 in the 1st surface 21, and is in a rough state. Fig. 9 as well as Fig.10 The first region 201 formed by the ablation process has a higher shape accuracy than the second region 202 and the third region 203 shown.

[0162] For the hole 23 formed by the manufacturing method of the substrate of Example 1, the surface roughness of the rough surface area 202c with reduced surface roughness was measured by a scanning electron microscope (SEM: Scanning Electron Microscope) on the smooth area 202b corresponding to the V-shaped concave portion of the first area 201 and the -Z side on both sides of the inner side surface of the hole 23. In addition, the hole 23 was selected to be a hole cleaned by wet sandblasting before measuring the surface roughness. As a result, in the smooth area 202b on the inner side surface of the hole 23, Sa=1.08μm, Sz=5.71μm. On the other hand, in the rough surface area 202c, Sa=2.45μm and Sz=20.08μm. Here, Sa is the arithmetic mean height and Sz is the maximum height. As a result, it was confirmed that a difference in surface roughness was found between the smooth area 202b and the rough surface area 202c, and the surface roughness of the smooth area 202b was smaller than that of the rough surface area 202c.

[0163] As mentioned above, although the preferred embodiment is described in detail, the present invention is not limited to the above-described embodiment, and various modifications and substitutions can be made to the above-described embodiment without departing from the scope of the claims.

[0164] For example, the shape of the inner side surface of the hole 23 may be various shapes. Fig.34 as well as Fig.35 It is a cross-sectional view of the hole 23 for explaining the shape of the inner side surface of the hole 23 . Fig.34 This is the first case. Fig.35 This is the second case. Fig.34 And 35 denotes a cross section of the hole 23 in the Z direction cut on a virtual plane including the central axis 230 of the hole 23 .

[0165] exist Fig.34 as well as Fig.35 Among the inner surfaces of the hole 23, the first inner surface 231 is the inner surface having the largest opening among the inner surfaces of the hole 23. The second inner surface 232 is the inner surface having the smallest opening among the inner surfaces of the hole 23.

[0166] exist Fig.34 In the example shown, the first inner side surface 231 is on the first surface 21 side. In addition, the second inner side surface 232 is located between the first surface 21 and the second surface 22. In the hole 23, the surface roughness of the first inner side surface 231 is lower than that of the second inner side surface 232 and is smoother. Fig.34The hole 23 shown can be formed by irradiating the second area 202 of the second surface 22 with the second laser 52 in the second processing step. When the second area 202 of the second surface 22 is irradiated with the second laser 52, the laser of the second laser 52 travels from the second surface 22 to the first surface 21. The processing energy of the laser decreases in the direction of travel. On the second surface 22 irradiated with the second laser 52, the processing energy of the laser is sufficiently large, but the processing energy of the laser between the first surface 21 and the second surface 22 is reduced, thereby forming a second inner surface 232 having a surface roughness greater than that of the first inner surface 231 and including a convex portion. Fig.34 In the hole 23 shown, the second inner side surface 232 is provided at a position away from the first surface 21 and the second surface 22, so that the profile (i.e., processing accuracy) of the hole 23 on the first surface 21 and the second surface 22 is not affected. Therefore, if it is desired to obtain a hole 23 having a highly accurately processed profile on both the first surface 21 and the second surface 22, it is preferred to irradiate the second laser 52 from the second surface 22 side.

[0167] On the other hand, Fig.35 In the example shown, the first inner side surface 231 is on the first surface 21 side. In addition, the second inner side surface 232 is on the second surface 22 side. Fig.35 In the example shown, in the hole 23, the opening of the first surface 21 is larger than the opening of the second surface 22. In the hole 23, the surface roughness of the first inner side surface 231 is lower than the surface roughness of the second inner side surface 232 and is smoother. Fig.35 The hole 23 shown can be formed by irradiating the second region 202 of the first surface 21 with the second laser 52 in the second processing step. When the second region 202 of the first surface 21 is irradiated with the second laser 52, the laser of the second laser 52 travels from the first surface 21 to the second surface 22. Since the processing energy of the laser decreases in the traveling direction, the opening diameter of the second surface 22 of the hole 23 is smaller than the opening diameter of the first surface 21 of the hole 23, and in the cross-sectional view of the hole 23 including the first surface 21 and the second surface 22, a convex portion having a surface roughness greater than that of the first inner surface 231 is formed on the second inner surface 232 of the hole 23 on the second surface 22 side. However, in Fig.35 The hole 23 shown can also be obtained by including a hole 23 having a contour processed with high precision on the first surface 21.

[0168] The method for manufacturing a substrate of the present invention can form a hole penetrating a ceramic substrate with high precision, and thus can be preferably applied to the manufacturing process of a ceramic substrate used in a light-emitting device such as a vehicle-mounted light source, a lighting light source, a light source for various indicators, a display light source, a light source for backlighting a liquid crystal, a signal light, a vehicle-mounted component, and a channel letter for a sign. However, the method for manufacturing a substrate of the present invention is not limited to the manufacturing process of a ceramic substrate used in a light-emitting device, and can also be applied to the manufacturing process of a ceramic substrate used in various applications.

[0169] The embodiment of the present invention can be described as follows, for example.

[0170] <Item 1> A method for manufacturing a substrate, comprising: a step of preparing a ceramic substrate, the ceramic substrate having a first surface and a second surface located on the opposite side of the first surface; a first processing step of ablation processing the first area in the ceramic substrate by irradiating the first area of ​​the first surface with a first laser having a first pulse width; a second processing step of irradiating a second laser having a second pulse width larger than the first pulse width with a second laser having a second pulse width to a second area separated from the first area of ​​either the first surface or the second surface in a plan view, so as to heat-process a third area including the first area and the second area, wherein in the second processing step, the third area and the area surrounded by the third area form a hole penetrating from the first surface to the second surface.

[0171] <Item 2> The method for manufacturing a substrate according to <Item 1> above, wherein in the first processing step, the first region is annular.

[0172] <Item 3> The method for manufacturing a substrate according to <Item 2> above, wherein, in the second processing step, the second region is located inside the first region.

[0173] <Item 4> The method for manufacturing a substrate according to <Item 3> above, wherein, in the ceramic substrate, a distance between the first region and the second region is 25.0 μm or more and 32.5 μm or less.

[0174] <Item 5> The method for manufacturing a substrate according to any one of <Item 1> to <Item 4> above, wherein the second region is located on the second surface.

[0175] <Item 6> The method for manufacturing a substrate according to any one of <Item 1> to <Item 5>, wherein in the first processing step, the first region after the ablation processing reaches from the first surface to the second surface.

[0176] <Item 7> The method for manufacturing a substrate according to any one of <Item 1> to <Item 6> above, wherein in the second processing step, the second region is annular.

[0177] <Item 8> The method for manufacturing a substrate according to any one of <Item 1> to <Item 7> above, wherein the first region has a rectangular shape in a plan view.

[0178] <Item 9> The method for manufacturing a substrate according to any one of <Item 1> to <Item 8>, wherein the first laser is a laser having a pulse width in the femtosecond region, and the second laser is a laser emitted from a CO 2 laser light source.

[0179] <Item 10> The method for manufacturing a substrate according to any one of <Item 1> to <Item 9> above, wherein a thickness of the ceramic substrate is 100 μm or more and 500 μm or less.

[0180] <Item 11> The method for manufacturing a substrate according to any one of <Item 1> to <Item 10> above, wherein the ceramic substrate is silicon nitride.

[0181] <Item 12> The method for manufacturing a substrate according to any one of <Item 1> to <Item 11>, further comprising a conductive component forming step of disposing a conductive paste in the hole and firing the conductive paste to form a conductive component.

[0182] <Item 13> According to the above <12> The method for manufacturing the substrate, wherein the conductive paste includes at least any one of Ti, Hf, Zr, Nb, Ce and Mg.

[0183] Explanation of symbols

[0184] 1. 1a, 1b, 1c Light-emitting part

[0185] 11 Luminous surface

[0186] 12 Light emitting elements

[0187] 13Translucent parts

[0188] 14 Covering parts

[0189] 2 substrates

[0190] 20Ceramic substrate

[0191] 21 Page 1

[0192] 22 Page 2

[0193] 23 holes

[0194] 230 center axis

[0195] 231 1st inner side

[0196] 232 2nd inner side

[0197] 24 1st electrode

[0198] 25 2nd electrode

[0199] 26 1st conductive adhesive component

[0200] 27. Second conductive adhesive component

[0201] 28 conductive parts

[0202] 3. Install the base plate

[0203] 31 3rd electrode

[0204] 32 Wiring

[0205] 33 4th electrode

[0206] 51 No.1 Laser

[0207] 52 2nd Laser

[0208] 100 Lighting Devices

[0209] 201 Area 1

[0210] 202 2nd area 203 3rd area 204 4th area C1 1st moving axis C2 2nd moving axis d1 1st distance d2 2nd distance E1 1st end surface E2 2nd end surface △ interval

Claims

1. A method for manufacturing a substrate, comprising: A step of preparing a ceramic substrate, the ceramic substrate having a first surface and a second surface located on the opposite side of the first surface; a first processing step of irradiating a first area of ​​the first surface with a first laser beam having a first pulse width to ablate the first area of ​​the ceramic substrate; and The second processing step comprises irradiating a second laser having a second pulse width greater than the first pulse width to a second area separated from the first area of ​​either the first surface or the second surface in a plan view, so as to perform thermal processing on a third area including the first area and the second area. In the second processing step, the third region and the region surrounded by the third region form a hole penetrating from the first surface to the second surface.

2. The method for manufacturing a substrate according to claim 1, wherein: In the first processing step, the first region is annular.

3. The method for manufacturing a substrate according to claim 2, wherein: In the second processing step, the second region is located inside the first region.

4. The method for manufacturing a substrate according to claim 3, wherein: In the ceramic substrate, a distance between the first region and the second region is greater than or equal to 25.0 μm and less than or equal to 32.5 μm.

5. The method for manufacturing a substrate according to any one of claims 1 to 4, wherein: The second region is located on the second surface.

6. The method for manufacturing a substrate according to any one of claims 1 to 5, wherein: In the first processing step, the first region after the ablation processing reaches from the first surface to the second surface.

7. The method for manufacturing a substrate according to any one of claims 1 to 6, wherein: In the second processing step, the second region is annular.

8. The method for manufacturing a substrate according to any one of claims 1 to 7, wherein: In a plan view, the first region has a rectangular shape.

9. The method for manufacturing a substrate according to any one of claims 1 to 8, wherein: The first laser is a laser with a pulse width in the femtosecond region, The second laser light is a laser light emitted from a CO 2 laser light source.

10. The method for manufacturing a substrate according to any one of claims 1 to 9, wherein: The ceramic substrate has a thickness of 100 μm or more and 500 μm or less.

11. The method for manufacturing a substrate according to any one of claims 1 to 10, wherein: The ceramic substrate is silicon nitride.

12. The method for manufacturing a substrate according to any one of claims 1 to 11, further comprising: The conductive member forming step is to arrange a conductive paste in the hole and to bake the conductive paste to form the conductive member.

13. The method for manufacturing a substrate according to claim 12, wherein: The conductive paste includes at least any one of Ti, Hf, Zr, Nb, Ce and Mg.

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