Substrate and light-emitting device

Abstract

The present invention provides a substrate and a light-emitting device that can improve the reliability of connections. [Solution] The substrate comprises a base body having a main surface, a conductive member disposed on the main surface, and a covering member. The conductive member has a first portion having a first conductive layer and an aluminum layer stacked in order from bottom to top, a second portion having a gold layer on its uppermost surface, and a third portion having the gold layer, the first conductive layer, and the aluminum layer stacked in order from bottom to top. The first boundary, which is the boundary between the first portion and the third portion, and the second boundary, which is the boundary between the second portion and the third portion, are covered by the covering member.

Description

[Technical Field]

[0001] This disclosure relates to a substrate and a light-emitting device. [Background technology]

[0002] Patent Document 1 discloses a light-emitting device having an aluminum-containing layer in the external connection region, which is the region for supplying power from an external source, and a gold-containing layer in the element mounting region, which is the region for mounting the light-emitting element. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-065001 [Overview of the project] [Problems that the invention aims to solve]

[0004] In recent years, there has been a growing demand for substrates and light-emitting devices that can ensure reliable connections.

[0005] This disclosure aims to provide a substrate and a light-emitting device that can improve the reliability of connections. [Means for solving the problem]

[0006] According to one aspect of the disclosed technology, the substrate comprises a base having a main surface, a conductive member disposed on the main surface, and a covering member, wherein the conductive member has a first portion having a first conductive layer and an aluminum layer stacked in order from bottom to top, a second portion having a gold layer on its uppermost surface, and a third portion having the gold layer, the first conductive layer and the aluminum layer stacked in order from bottom to top, and the first boundary, which is the boundary between the first portion and the third portion, and the second boundary, which is the boundary between the second portion and the third portion, are covered by the covering member.

[0007] According to one aspect of the disclosed technology, the substrate comprises a base body having a main surface and a conductive member disposed on the main surface, the conductive member having a first portion having a first conductive layer and an aluminum layer stacked in order from bottom to top, a second portion having a gold layer on its uppermost surface, and a third portion having the gold layer, the first conductive layer and the aluminum layer stacked in order from bottom to top, the conductive member having a second conductive layer including a first layer between the gold layer and the base body, and a void disposed between the first conductive layer and the first layer.

[0008] According to one aspect of the disclosed technology, the light-emitting device comprises a substrate and a light-emitting element, wherein the light-emitting element is connected to the gold layer in the second portion. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a substrate and a light-emitting device that can improve the reliability of connections. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic perspective view showing the light-emitting device according to the first embodiment. [Figure 2] This is a schematic top view showing a light-emitting device according to the first embodiment. [Figure 3] This is a schematic top view showing the substrate constituting the light-emitting device according to the first embodiment. [Figure 4] This is a cross-sectional view along line IV-IV in Figure 2. [Figure 5A] This is a schematic cross-sectional view showing only the substrate according to the first embodiment or a substrate included in the light-emitting device. [Figure 5B] This is a schematic top view showing the first boundary of the first embodiment. [Figure 5C] This is a schematic top view showing the first boundary of a modified example of the first embodiment. [Figure 6A] This is a cross-sectional view showing a method for manufacturing a substrate included in the light-emitting device according to the first embodiment. [Figure 6B]It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the first embodiment. [Figure 6C] It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the first embodiment. [Figure 6D] It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the first embodiment. [Figure 6E] It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the first embodiment. [Figure 6F] It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the first embodiment. [Figure 6G] It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the first embodiment. [Figure 7A] It is a partial cross-sectional view explaining the manufacturing process of a light-emitting device according to the first embodiment. [Figure 7B] It is a partial cross-sectional view explaining the manufacturing process of a light-emitting device according to the first embodiment. [Figure 7C] It is a partial cross-sectional view explaining the manufacturing process of a light-emitting device according to the first embodiment. [Figure 7D] It is a top view explaining the manufacturing process of a light-emitting device according to the first embodiment. [Figure 7E] It is a partial cross-sectional view explaining the manufacturing process of a light-emitting device according to the first embodiment. [Figure 8] It is a cross-sectional view schematically showing a substrate constituting a light-emitting device according to the second embodiment. [Figure 9A] It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the second embodiment. [Figure 9B] It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the second embodiment. [Figure 9C] It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the second embodiment. [Figure 9D] It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the second embodiment. [Figure 9E] It is a cross-sectional view showing a method for manufacturing a substrate included in a light-emitting device according to the second embodiment. [Figure 10] This is an enlarged cross-sectional view of region X in Figure 9A. [Modes for carrying out the invention]

[0011] Hereinafter, a manufacturing method of an embodiment of the present invention and a light-emitting device obtained by the manufacturing method (hereinafter sometimes referred to as the "light-emitting device according to the embodiment") will be described with reference to the drawings. In the following description, terms indicating specific directions or positions (for example, "up," "down," and other terms including these terms) will be used as needed. However, the use of these terms is for the purpose of facilitating the understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms. Furthermore, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components.

[0012] Furthermore, the embodiments shown below are illustrative examples of light-emitting devices and the like that embody the technical concept of the present invention, and do not limit the present invention to the following. Also, the dimensions, materials, shapes, relative arrangements, etc. of the components described below are intended to be illustrative, and not to limit the scope of the present invention unless otherwise specified. In addition, the content described in one embodiment is applicable to other embodiments and modifications. Furthermore, the size and positional relationships of the members shown in the drawings may be exaggerated in order to clarify the explanation. In addition, in order to avoid the drawings becoming excessively complex, schematic diagrams that omit the illustration of some elements may be used, or end view diagrams that show only the cross-section may be used as cross-sectional views.

[0013] <Light-emitting device according to the first embodiment> A first embodiment will now be described. Figure 1 is a schematic perspective view showing a light-emitting device according to the first embodiment. Figure 2 is a schematic top view showing a light-emitting device according to the first embodiment. Figure 3 is a schematic top view showing only the substrate according to the first embodiment or the substrate included in the light-emitting device. Figure 4 is a cross-sectional view taken along the line IV-IV in Figure 2. Figure 5A is a schematic cross-sectional view showing the substrate constituting the light-emitting device according to the first embodiment, and corresponds to the cross-sectional view taken along the line VV in Figure 2.

[0014] As shown in Figures 1 to 4 and Figure 5A, the light-emitting device 1 according to the first embodiment includes a substrate 10 and a light-emitting element 20. The substrate 10 comprises a base body 11 having a main surface 11A and a conductive member 12 disposed on the main surface 11A. The substrate 10 according to the first embodiment further includes a covering member 60 that covers at least a part of the conductive member 12. In the first embodiment, the conductive member 12 is a wiring, and the substrate 10 equipped with the conductive member 12 is a wiring board. The main surface 11A of the base body 11 is the upper surface 11A of the base body 11. Note that Figure 3 may show the substrate 10 without the covering member 60. Figure 5A may show the substrate 10 alone, the substrate 10 included in the light-emitting device 1, or the substrate 10 without the covering member 60.

[0015] In the first embodiment, the light-emitting device 1 has a plurality of light-emitting elements 20, and in the light-emitting device 1, the plurality of light-emitting elements 20 can be made to emit light independently.

[0016] In the light-emitting device 1, a plurality of light-emitting elements 20 are mounted on a substrate 10. Each light-emitting element 20 has an upper surface 20a, a plurality of side surfaces 20c connected to the upper surface 20a, and a lower surface 20b opposite to the upper surface 20a. The plurality of side surfaces 20c are connected to the upper surface 20a and the lower surface 20b. In other words, each of the plurality of side surfaces 20c has an outer edge connected to the outer edge of the upper surface 20a and the outer edge of the lower surface 20b. Light is emitted from the upper surface 20a, the lower surface 20b, and the side surfaces 20c of the light-emitting element 20.

[0017] The light-emitting element 20 has a substantially rectangular top surface 20a. For example, the external shape of the light-emitting element 20 is substantially a rectangular parallelepiped or a substantially cube. In this case, the top surface 20a and bottom surface 20b of the light-emitting element 20 are substantially rectangular, and the light-emitting element 20 has four substantially rectangular sides 20c. The shape of the top surface 20a of the light-emitting element 20 may be a polygon such as a triangle or a hexagon. Alternatively, the external shape of the light-emitting element 20 may be a columnar body or a frustum body with a polygonal top surface.

[0018] The light-emitting device 1 further includes translucent members 50. In the first embodiment, a plurality of translucent members 50 are arranged on each of the plurality of light-emitting elements 20. The number of translucent members 50 is, for example, the same as the number of light-emitting elements 20. The distance between adjacent translucent members 50 is, for example, 20 μm or more and 200 μm or less. A single translucent member 50 common to the plurality of light-emitting elements 20 may be arranged on each of the plurality of light-emitting elements 20. The translucent member 50 has an upper surface 50a, a lower surface 50b opposite to the upper surface 50a, and a side surface 50c between the upper surface 50a and the lower surface 50b. The upper surface 50a of the translucent member 50 constitutes a part of the upper surface of the light-emitting device 1 as the main light-emitting surface of the light-emitting device 1. The lower surface 50b of the translucent member 50 is joined to the upper surface 20a of the light-emitting element 20. The light-transmitting member 50 and the light-emitting element 20 may be joined via a light-transmitting adhesive made of silicone resin or the like, which is placed between the lower surface 50b of the light-transmitting member 50 and the upper surface 20a of the light-emitting element 20, or the lower surface 50b of the light-transmitting member 50 and the upper surface 20a of the light-emitting element 20 may be in contact. The light-transmitting member 50 is positioned such that its lower surface 50b is substantially parallel to the upper surface 20a of the light-emitting element 20. Preferably, the shape of the lower surface 50b of the light-transmitting member 50 is the same as or similar to the shape of the upper surface 20a of the light-emitting element 20. For example, if the upper surface 20a of the light-emitting element 20 is rectangular, it is preferable that the lower surface 50b of the light-transmitting member 50 is also rectangular. The number of light-transmitting members 50 provided in the light-emitting device 1 may be less than the number of light-emitting elements 20. The statement that the light-emitting device 1 comprises a number of light-transmitting members less than the number of light-emitting elements 20 includes, for example, a configuration in which at least one of the light-transmitting members is arranged to cover the multiple light-emitting elements 20 collectively.

[0019] The lower surface 50b of the light-transmitting member 50 is a flat surface. The upper surface 50a of the light-transmitting member 50 may be a flat surface parallel to the lower surface 50b, or part or all of the upper surface 50a may have a surface that is not parallel to the lower surface 50b. The side surface 50c of the light-transmitting member 50 may be a surface perpendicular to at least one of the upper surface 50a and the lower surface 50b, an inclined surface, a curved surface, etc. The light-transmitting member 50 may have an uneven surface structure on part or all of its surface.

[0020] The lower surface 50b of the light-transmitting member 50 has a larger area than the upper surface 20a of the light-emitting element 20. In this case, it is preferable that the light-transmitting member 50 is positioned such that, when viewed from above, the lower surface 50b of the light-transmitting member 50 encloses the light-emitting element 20. Alternatively, the lower surface 50b of the light-transmitting member 50 may have a smaller area than the upper surface 20a of the light-emitting element 20, or they may have the same area.

[0021] In the light-emitting device 1, the covering member 60 exposes the upper surface 50a of each light-transmitting member 50 and covers the side surfaces 50c of each light-transmitting member 50 and the side surfaces 20c of each light-emitting element 20 together. The covering member 60 may cover at least a portion of the upper surface of the substrate 10. The light-emitting device 1 may further have a protective element mounted on the substrate 10 to protect the light-emitting elements 20. The protective element is, for example, a Zener diode. If the light-emitting device 1 has a protective element, it is preferable that the covering member 60 covers the upper surface, lower surface, and side surfaces of the protective element. Furthermore, the covering member 60 may also cover the lower surface 20b of each light-emitting element 20. Note that the covering member 60 is not limited to the above configuration. For example, the covering member 60 may cover only at least a portion of the conductive member 12 without contacting the light-emitting elements 20.

[0022] In the light-emitting device 1, the covering member 60, together with the base body 11 of the substrate 10, constitutes the side surface of the light-emitting device 1. In the first embodiment, the side surface of the covering member 60 and the side surface of the base body 11 that constitute the side surface of the light-emitting device 1 are the same plane. Also, the upper surface 60a of the covering member 60 and the upper surface 50a of the light-transmitting member 50 that constitute the upper surface of the light-emitting device 1 are the same plane. However, the side surface of the covering member 60 and the side surface of the base body 11 do not have to be the same plane, and the upper surface 60a of the covering member 60 and the upper surface 50a of the light-transmitting member 50 do not have to be the same plane.

[0023] The substrate 10 according to the first embodiment comprises a base body 11 and a conductive member 12 disposed on the main surface 11A (upper surface 11A in the first embodiment) of the base body 11. In the first embodiment, the case in which a covering member 60 is included in the substrate 10 is described, but the covering member 60 may not be included in the substrate 10. The base body 11 supports the conductive member 12. The substrate 10 is a member on which the light-emitting element 20 is mounted. The conductive member 12 has an external connection part 12a and is used to supply power to the light-emitting element 20 from the outside. The substrate 10 may also have wiring on the lower surface located opposite the upper surface 11A of the base body 11.

[0024] The substrate 11 is, for example, a roughly rectangular parallelepiped or roughly cubic shape. It is preferable to use a material for the substrate 11 that does not easily transmit light emitted from the light-emitting element 20 and ambient light. Examples of materials for the substrate 11 include ceramics such as aluminum oxide, aluminum nitride, silicon nitride, and mullite; resins such as epoxy resin, silicone resin, modified epoxy resin, urethane resin, phenolic resin, polyimide resin, BT resin, and polyphthalamide; semiconductors such as silicon; metals such as copper and aluminum; single materials of graphite and composite materials thereof. Among these, ceramics with excellent heat dissipation properties can be suitably used as the material for the substrate 11. Nitride ceramics are preferred as the material for the substrate 11. Nitride ceramics are, for example, silicon nitride or aluminum nitride. The thickness of the substrate 11 is, for example, 0.1 mm to 0.5 mm in the case of silicon nitride, and 0.3 mm to 2 mm in the case of aluminum nitride. The upper surface 11A of the base body 11 has a first region 91 on which the covering member 60 is placed, and a second region 92 that is exposed from the covering member 60.

[0025] The conductive member 12 has a first portion 81 having a first conductive layer 31 and an aluminum layer 32 stacked from bottom to top, a second portion 82 having a gold layer 33 on its uppermost surface, and a third portion 83 having a gold layer 33, a first conductive layer 31, and an aluminum layer 32 stacked from bottom to top. The first boundary 86, which is the boundary between the first portion 81 and the third portion 83, and the second boundary 87, which is the boundary between the second portion 82 and the third portion 83, are covered by a covering member 60. In the first embodiment, the ionization tendency of the first conductive layer 31 is lower than that of the aluminum layer 32.

[0026] The conductive member 12 has a second conductive layer 34 between the gold layer 33 and the substrate 11. The second conductive layer 34 has a first layer 41. In the example shown in Figure 5A, the second conductive layer 34 has a first layer 41 and a seed layer 42 stacked from bottom to top. The first layer 41 contains nickel and chromium. In the first embodiment, the first layer 41 contains a nickel-chromium alloy. The first layer 41 is placed on the substrate 11. The first layer 41 and the substrate 11 are in contact with each other. The thickness of the first layer 41 is, for example, 0.025 μm or more and 0.25 μm or less. For the seed layer 42, for example, gold can be used. The thickness of the seed layer 42 is, for example, 0.025 μm or more and 0.25 μm or less. The thickness of the second conductive layer 34 is, for example, 0.05 μm or more and 0.5 μm or less. The second conductive layer 34 is placed only in the second portion 82 and the third portion 83, and not in the first portion 81. The end 41A of the first layer 41 is located at the third portion 83, and the end 42A of the seed layer 42 is located at the first boundary 86. The first layer 41 and the seed layer 42 may contain a native oxide film on at least one of their respective surfaces and interfaces. When a native oxide film is present on the respective surfaces and interfaces of the first layer 41 and the seed layer 42, the native oxide film is thin enough to conduct electricity, so the first layer 41, the seed layer 42, and the substrate 11 can be considered to be in contact with each other.

[0027] Nickel readily forms a native oxide film on its surface. Furthermore, nickel exhibits good adhesion to ceramics and gold. Chromium exhibits good adhesion to gold. As a result, high adhesion is obtained between the first layer 41 containing the nickel-chromium alloy and the substrate 11, and high adhesion is also obtained between the first layer 41 containing the nickel-chromium alloy and the seed layer 42 and gold layer 33 containing gold.

[0028] The gold layer 33 is located only in the second portion 82 and the third portion 83, and not in the first portion 81. The thickness of the gold layer 33 is, for example, 1 μm to 5 μm. The gold layer 33 may contain a native oxide film on its surface. Gold is a soft metal with high electrical and thermal conductivity. For this reason, the gold layer 33 provides good mountability and connection reliability in flip-chip mounting using gold bumps for the light-emitting element 20.

[0029] The first conductive layer 31 is located only in the first portion 81 and the third portion 83, and not in the second portion 82. The first conductive layer 31 contains at least one of titanium or ruthenium. The thickness of the first conductive layer 31 is, for example, 0.05 μm or more and 0.5 μm or less. The thickness of the first conductive layer 31 located on the side surface of the gold layer 33 is thinner than the thickness of the first conductive layer 31 located on the top surface of the gold layer 33 and the top surface of the substrate 11. The thinness of the first conductive layer 31 located on the side surface of the gold layer 33 makes it possible to lower the electrical resistance between the aluminum layer 32 and the gold layer 33 with the first conductive layer 31 sandwiched in between. The first conductive layer 31 and the substrate 11 are in contact with each other. A gap 43 is located between the first conductive layer 31 and the first layer 41. The first conductive layer 31 and the first layer 41 may be in contact or separated. When the first conductive layer 31 and the first layer 41 are in contact, the gap 43 is the space surrounded by the first conductive layer 31, the first layer 41, and the seed layer 42. When the first conductive layer 31 and the first layer 41 are separated, the gap 43 is the space surrounded by the first conductive layer 31, the first layer 41, the seed layer 42, and the substrate 11. A part of the first conductive layer 31 may be located in the third part 83. If the first conductive layer 31 is interrupted as described later, the gap 43 may be further surrounded by the aluminum layer 32, as the aluminum layer 32 is exposed to the gap 43 side from the interrupted portion.

[0030] Figure 5B is a schematic top view showing the first boundary of the first embodiment, and is an enlarged top view of region Y in Figure 3. Figure 5B shows the aluminum layer 32 and the gold layer 33 of the conductive member 12. In the example shown in Figure 5B, in the first boundary 86B, which is an example of the first boundary 86, the edge of the gold layer 33 that overlaps with the aluminum layer 32 in a top view is straight. In the first embodiment, in a top view, the first boundary 86B substantially overlaps with the straight section 86b, which is a line segment connecting two intersection points between the first boundary 86 and the contour of the aluminum layer 32, and the length of the first boundary 86 is substantially equal to the length of the straight section 86b.

[0031] Native oxide films are easily formed on the surfaces of titanium and ruthenium. Furthermore, titanium and ruthenium have strong resistance to halogens, and therefore have high resistance to chlorides such as sodium chloride that contain halogens. In the first conductive layer 31 containing titanium or ruthenium, the titanium or ruthenium is in contact with the nitride substrate 11 in the first portion 81. For example, when the conductive member 12 is heat-treated, titanium nitride or ruthenium nitride is formed at the interface between the first conductive layer 31 and the substrate 11, and high adhesion between the titanium or ruthenium and the nitride is obtained due to the titanium nitride or ruthenium nitride.

[0032] The aluminum layer 32 is located only in the first portion 81 and the third portion 83, and not in the second portion 82. The thickness of the aluminum layer 32 is, for example, 1 μm or more and 10 μm or less. If the thickness of the aluminum layer 32 is greater than the thickness of the gold layer 33, the difference in height of the upper surface of the aluminum layer 32 caused by the overlap of the aluminum layer 32 and the gold layer 33 in the first portion 81 and the third portion 83 can be reduced, thereby reducing the occurrence of interruptions in the aluminum layer 32. The thickness of the aluminum layer 32 in a direction parallel to the upper surface 11A of the substrate 11, located on the side surface of the first conductive layer 31 (R1 shown in Figure 5A), is thinner than the thickness of the aluminum layer 32 in a direction perpendicular to the upper surface 11A of the substrate 11, located above the gold layer 33 and above the substrate 11 in contact with the first conductive layer 31 (R2 shown in Figure 5A). The aluminum layer 32 may contain a native oxide film on its surface. When aluminum wire is used for bonding, the aluminum layer 32 has excellent bonding properties to the aluminum wire because they are made of the same type of metal.

[0033] The first conductive layer 31 and the aluminum layer 32 may contain a native oxide film on at least one of their respective surfaces and interfaces. Because the adhesion between the titanium or ruthenium oxide film and the aluminum oxide film is good, the first conductive layer 31 and the aluminum layer 32 have excellent adhesion. When a native oxide film is present on the respective surfaces and interfaces of the first conductive layer 31 and the aluminum layer 32, the native oxide film is thin enough to conduct electricity, so the first conductive layer 31 and the aluminum layer 32 can be considered to be in contact with each other.

[0034] In the conductive member 12, the thickness of the third portion 83 is greater than the thickness of the outer edge of the first portion 81 and the thickness of the second portion 82. For example, the thickness of the third portion 83 is greater than the thickness of the portion of the first portion 81 exposed from the covering member 60 and the thickness of the second portion 82.

[0035] If the substrate 11 has wiring on its underside, this wiring may include an anode electrode and a cathode electrode that are electrically connected to an external power supply. Furthermore, if the substrate 10 has wiring on its underside, it may be provided with relay wiring on at least one of the interior and side surfaces of the substrate 11 for connecting the conductive member 12 to the wiring located on the underside of the substrate 11. In addition, the conductive member 12 on the underside of the substrate 11 may include wiring for heat dissipation, in addition to the anode electrode and cathode electrode that are electrically connected to the light-emitting element 20. For example, the wiring on the underside of the substrate 11 can be made of a metal such as iron, copper, nickel, aluminum, gold, silver, platinum, titanium, tungsten, or palladium, or an alloy containing at least one of these.

[0036] The substrate 10 does not necessarily have wiring on the underside of the base body 11. In this case, an anode electrode and a cathode electrode, which are electrically connected to an external power supply, may be arranged on the top or side surface of the base body 11.

[0037] The substrate 10 may have a recess on its upper surface, and the light-emitting device 1 may have a structure in which the light-emitting element 20 is positioned at the bottom of the recess of the substrate 10.

[0038] Furthermore, the substrate 10 may further include an insulating member that covers the base body 11 and at least a first portion of the conductive member 12.

[0039] The following describes in detail each element constituting the light-emitting device 1 according to the embodiment.

[0040] (Light-emitting element 20) The light-emitting element 20 can preferably be a semiconductor light-emitting element such as a light-emitting diode (LED) chip or a semiconductor laser (LD) chip. The shape and size of the light-emitting element 20 can be selected arbitrarily. The light-emitting element 20 has, for example, a plurality of electrodes on its lower surface 20b. The light-emitting element 20 is placed on a substrate 10. The light-emitting element 20 is flip-chip mounted on the substrate 10 with, for example, its lower surface 20b with electrodes facing the substrate 10. The plurality of electrodes of the light-emitting element 20 are electrically connected to a conductive member 12. The light-emitting element 20 and the conductive member 12 can be connected using a known conductive bonding member 25 such as eutectic solder, conductive paste, or bumps. Alternatively, the electrodes of the light-emitting element 20 and the conductive member 12 may be directly joined without the use of a conductive bonding member 25.

[0041] The light-emitting element 20 includes, for example, a semiconductor structure and a support substrate that supports the semiconductor structure. The semiconductor structure includes an n-side semiconductor layer, a p-side semiconductor layer, and an active layer sandwiched between the n-side semiconductor layer and the p-side semiconductor layer. The active layer may be a single quantum well (SQW) structure or a multiple quantum well (MQW) structure including multiple well layers. The semiconductor structure includes multiple semiconductor layers made of nitride semiconductors. The nitride semiconductor is In x Al y Ga 1-x-y The semiconductor comprises all compositions in which the composition ratios x and y are varied within their respective ranges in the chemical formula N (0 ≤ x, 0 ≤ y, x + y ≤ 1). The emission peak wavelength of the active layer can be appropriately selected depending on the purpose. The active layer is configured to emit, for example, visible light or ultraviolet light.

[0042] A semiconductor structure may include multiple light-emitting sections, each containing an n-side semiconductor layer, an active layer, and a p-side semiconductor layer. When a semiconductor structure includes multiple light-emitting sections, each light-emitting section may include well layers with different emission peak wavelengths, or well layers with the same emission peak wavelength. Note that "same emission peak wavelength" includes variations of a few nanometers. The combination of emission peak wavelengths of the multiple light-emitting sections can be selected as appropriate. For example, when a semiconductor structure includes two light-emitting sections, possible combinations of light emitted by each section include blue light and blue light, green light and green light, red light and red light, ultraviolet light and ultraviolet light, blue light and green light, blue light and red light, or green light and red light. For example, when a semiconductor structure includes three light-emitting sections, possible combinations of light emitted by each section include blue light, green light, and red light. Each light-emitting section may include one or more well layers with emission peak wavelengths different from the other well layers.

[0043] The light-emitting element 20 shown in Figure 4 has one semiconductor structure on one support substrate. The single semiconductor structure has only one light-emitting layer. However, the light-emitting element 20 may have multiple semiconductor stacks on one support substrate. Also, a single semiconductor structure may have multiple light-emitting layers. The structure of the semiconductor structure having multiple light-emitting layers may include multiple active layers between one n-side semiconductor layer and one p-side semiconductor layer, or it may be a structure in which the sequence of an n-side semiconductor layer, an active layer, and a p-side semiconductor layer is repeated multiple times.

[0044] In the light-emitting element 20, multiple electrodes are arranged on a semiconductor structure. The electrodes include an n electrode connected to the n-side semiconductor layer and a p electrode connected to the p-side semiconductor layer. The p electrode and n electrode may be arranged on different sides of the semiconductor laminate or on the same side. Here, the multiple electrodes, including the p electrode and n electrode, are arranged on the same side of the semiconductor structure, with the side on which the multiple electrodes are arranged forming the lower surface 20b of the light-emitting element 20, and the side of the support substrate opposite to the side on which the semiconductor structure is arranged forming the upper surface 20a of the light-emitting element 20. Examples of support substrates include insulating substrates such as sapphire or spinel (MgAl2O4), and nitride-based semiconductor substrates such as gallium nitride. It is preferable to use a light-transmitting material for the support substrate in order to extract the light emitted from the active layer through the support substrate. Note that the light-emitting element 20 does not necessarily have a support substrate. For example, the support substrate can be removed after forming the semiconductor structure on the support substrate.

[0045] (Translucent member 50) The light-transmitting member 50 is placed on the light-emitting element 20 and transmits light emitted from the light-emitting element 20 to the outside. The light-transmitting member 50 transmits 60% or more of the light from the light-emitting element 20 and the light whose wavelength has been converted by the phosphor described later (for example, light having an emission peak wavelength in the wavelength range of 320 nm to 850 nm), and it is preferable that it transmits 70% or more of the light. The light-transmitting member 50 may be formed from any of the following: an inorganic material such as glass, ceramic, or sapphire; an organic material such as a resin containing one or more of the following: silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, acrylic resin, phenolic resin, or fluororesin; or a hybrid resin.

[0046] The light-transmissive member 50 may contain a phosphor capable of wavelength-converting at least a part of the incident light. Examples of the light-transmissive member 50 containing a phosphor include a sintered body of a phosphor and a material obtained by incorporating phosphor powder into the above-described material. Further, the light-transmissive member 50 may be one in which a light-transmissive layer such as a resin layer containing a phosphor or a glass layer containing a phosphor is formed on the surface of a molded body such as resin, glass, or ceramic. Further, the light-transmissive member 50 may contain a filler such as a light diffusing material according to the purpose. Further, when containing a filler such as a light diffusing material, the light-transmissive member 50 may be one in which a filler is incorporated into resin, glass, ceramic, or other inorganic substances, or may be one in which a light-transmissive layer such as a resin layer containing a filler or a glass layer containing a filler is formed on the surface of a light-transmissive plate which is a molded body of resin, glass, ceramic, etc.

[0047] The phosphors include yttrium aluminum garnet-based phosphors (e.g., (Y,Gd)3(Al,Ga)5O 12 :Ce), lutetium aluminum garnet-based phosphors (e.g., Lu3(Al,Ga)5O 12 :Ce), terbium aluminum garnet-based phosphors (e.g., Tb3(Al,Ga)5O 12 :Ce), CCA-based phosphors (e.g., Ca 10 (PO4)6Cl2:Eu), SAE-based phosphors (e.g., Sr4Al 14 O 25 :Eu), chlorosilicate-based phosphors (e.g., Ca8MgSi4O 16 Cl2: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)3Si6N 11: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), etc., nitride-based phosphors, KSF-based phosphors (e.g., K2SiF6:Mn), KSAF-based phosphors (e.g., K2(Si 1-x Al x )F 6-x :Mn where x satisfies 0 < x < 1), or fluoride-based phosphors such as MGF-based phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn), quantum dots having a perovskite structure (e.g., (Cs,FA,MA)(Pb,Sn)(F,Cl,Br,I)3 where FA and MA represent formamidinium 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. can be used.

[0048] As the light diffusing material, those known in the art can be used. For example, titanium dioxide, silicon dioxide, aluminum oxide, barium titanate, etc. can be used.

[0049] Also, when the light-transmitting member 50 includes at least one of the phosphor layer and the light diffusing material layer and a resin is used as the base material of the phosphor layer and the light diffusing material layer, examples of the resin include thermosetting resins such as epoxy resins, modified epoxy resins, silicone resins, modified silicone resins, etc.

[0050] (Coating member 60) The first boundary 86 and the second boundary 87 are covered by the covering member 60. The first boundary 86 is the boundary between the first portion 81 and the third portion 83. The second boundary 87 is the boundary between the second portion 82 and the third portion 83. The light-emitting element 20 is connected to the gold layer 33 at the second portion 82 of the conductive member 12. The light-emitting element 20 is also covered by the covering member 60. The covering member 60 preferably has light-shielding properties, and more preferably has at least one of light reflectivity and light absorption. In particular, it is preferable that it contains a material that can suitably reflect light emitted from the light-emitting element 20. For example, it is preferable that it has a reflectance of 60% or more with respect to light emitted from the light-emitting element 20, and more preferably 70% or more, 80% or more, or 90% or more.

[0051] The covering member 60 covers the side surface 20c of the light-emitting element 20, so that light emitted from the side surface 20c of the light-emitting element 20 is reflected by the covering member 60. Also, the covering member 60 covers the bottom surface 20b of the light-emitting element 20, so that light traveling downwards through the light-emitting element 20 is reflected by the covering member 60. These measures improve the light extraction efficiency of the light-emitting device 1. The covering member 60 may be composed of a single resin, as described later, or it may be composed of multiple different materials including a resin and a light-reflective or light-absorbing substance.

[0052] The covering member 60 is preferably made of an insulating material. Examples of resins used for the covering member 60 include silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, urea resin, acrylic resin, phenolic resin, bismaleimidotriazine resin, polyphthalamide resin, and polyimide resin, as well as a resin or hybrid resin containing one or more of these. Among these, it is particularly preferable to use a silicone resin that has excellent light resistance, heat resistance, electrical insulation properties, and flexibility. The covering member 60 may also be, for example, a member made of a translucent resin containing a light-reflecting substance or a light-absorbing substance. Examples of light-reflecting substances include titanium dioxide, silicon dioxide, aluminum oxide, zirconium dioxide, magnesium oxide, potassium titanate, barium titanate, zinc oxide, silicon nitride, aluminum nitride, boron nitride, calcium carbonate, calcium hydroxide, calcium silicate, and combinations thereof. Among these, it is preferable to use titanium dioxide, which has a relatively high refractive index, from the viewpoint of light reflection. An example of a light-absorbing substance is carbon black.

[0053] In the light-emitting device 1, aluminum wires can be bonded to the aluminum layer 32 exposed from the covering member 60. Furthermore, since the gold layer 33 can be used for wiring, the resistance of the wiring can be easily reduced. In addition, the conductive bonding member 25 has good wettability with respect to the gold layer 33, ensuring reliable connection between the light-emitting element 20 and the gold layer 33.

[0054] On the other hand, galvanic corrosion can occur if the aluminum layer 32 and the gold layer 33 come into contact. Saltwater is one of the factors that accelerates galvanic corrosion. In contrast, in the first embodiment, the first conductive layer 31 and the aluminum layer 32 are laminated from bottom to top in the first portion 81, the second portion 82 has the gold layer 33 on its uppermost surface, and the gold layer 33, the first conductive layer 31, and the aluminum layer 32 are laminated from bottom to top in the third portion 83. Furthermore, the first boundary 86, which is the boundary between the first portion 81 and the third portion 83, and the second boundary 87, which is the boundary between the second portion 82 and the third portion 83, are covered by the covering member 60. Because of the high adhesion between the first conductive layer 31 and the substrate 11, substances such as saltwater are unlikely to penetrate into the substrate 10 through the interface between the first conductive layer 31 and the substrate 11. Furthermore, because of the high adhesion between the first conductive layer 31 and the aluminum layer 32, substances such as saltwater have difficulty penetrating the substrate 10 through the interface between the first conductive layer 31 and the aluminum layer 32. Moreover, even if substances such as saltwater penetrate the substrate 10 from point P through the interface between the coating member 60 and the aluminum layer 32, the presence of the third portion 83 between the first portion 81 and the second portion 82 makes the path to the gold layer 33 indicated by point Q long, making it difficult for the substances to reach the gold layer 33. In other words, it is possible to prevent the aluminum layer 32 and the gold layer 33 from coming into contact with substances such as saltwater, thereby preventing the occurrence of galvanic corrosion. Thus, corrosion resistance can be improved with the substrate 10 and the light-emitting device 1. In particular, because the ionization tendency of the first conductive layer 31 is lower than that of the aluminum layer 32, the ionization tendency of the first conductive layer 31 is located between the ionization tendency of aluminum and the ionization tendency of gold, making it easier to reduce the occurrence of galvanic corrosion of the aluminum layer 32.

[0055] Furthermore, if the thickness of the third portion 83 is greater than the thickness at the outer edge of the first portion 81 and the thickness of the second portion 82, even if a substance such as saltwater enters the substrate 10 from point P through the interface between the coating member 60 and the aluminum layer 32, at least two movements in a direction substantially perpendicular to the main surface 11A are required in the third portion 83 before it reaches the gold layer 33 indicated by point Q. Therefore, the likelihood of a substance such as saltwater reaching the gold layer 33 can be further reduced.

[0056] When the substrate 11 contains a nitride ceramic, and a second conductive layer 34 is placed between the gold layer 33 and the substrate 11, and the second conductive layer 34 contains nickel and chromium, high adhesion is obtained between the substrate 11 and the second conductive layer 34, and high adhesion is obtained between the second conductive layer 34 and the gold layer 33, thus high adhesion is obtained between the substrate 11 and the gold layer 33.

[0057] In the first embodiment, the first conductive layer 31 contains at least one of titanium or ruthenium, and a gap 43 is arranged between the first conductive layer 31 and the first layer 41. This reduces the diffusion of metallic elements such as nickel contained in the first layer 41 into the first conductive layer 31.

[0058] The thickness of the first conductive layer 31 may be thinner or thicker than the thickness of the second conductive layer 34, or the thickness of the first conductive layer 31 may be equal to the thickness of the second conductive layer 34. When the thickness of the first conductive layer 31 is thicker than the thickness of the second conductive layer 34, the occurrence of interruptions due to insufficient film formation of the first conductive layer 31 near the first boundary 86 is reduced, and the continuity of the film is easily obtained. In the first embodiment, even if an interruption of the first conductive layer 31 occurs near the first boundary 86, the distance from the end of the first conductive layer 31 in the first portion 81 to the first boundary 86 is long, the adhesion between the first conductive layer 31 and the substrate 11 is high, and the first boundary 86 is covered by the covering member 60, so the occurrence of galvanic corrosion can be sufficiently reduced.

[0059] When the first conductive layer 31 contains titanium or ruthenium, a native oxide film is formed on the surface of the first conductive layer 31. A native oxide film is also formed on the surface of the aluminum layer 32. Thus, because native oxide films are formed on the surface of the first layer 41 and the surface of the aluminum layer 32, high adhesion is obtained between the oxide film on the surface of the first conductive layer 31 and the oxide film on the surface of the aluminum layer 32. Furthermore, when the first conductive layer 31 and the substrate 11 are in contact with each other, heat treatment of the conductive member 12 generates nitrides at the interface between the first conductive layer 31 and the substrate 11 due to the titanium or ruthenium contained in the first conductive layer 31 and the nitrogen contained in the substrate 11. Therefore, high adhesion is obtained between the first conductive layer 31 and the substrate 11.

[0060] In a top view, it is preferable that the area of ​​the third portion 83 is smaller than the area of ​​the first portion 81. This allows for miniaturization of the light-emitting device 1 and facilitates wire bonding to the portion of the first portion 81 that is exposed from the covering member 60.

[0061] On the upper surface 11A of the substrate 11, the distance L1 between the third boundary 93, which is the boundary between the first region 91 and the second region 92, and the first boundary 86 is preferably 10 μm or more. This increases the top view area of ​​the portion of the first part 81 of the conductive member 12 that is covered by the covering member 60, making it more difficult for substances such as saltwater to reach the gold layer 33, thereby reducing the occurrence of galvanic corrosion and improving the reliability of the connection of the light-emitting device 1. The distance L1 is more preferably 20 μm or more, and even more preferably 30 μm or more. The distance L1 is, for example, 1000 μm or less. Note that the distance L1 is the distance in a direction parallel to the upper surface 11A of the substrate 11.

[0062] Furthermore, in a top view, the distance L2 from the third boundary 93 to the outer edge of the first portion 81 is preferably 100 μm or more. This makes it easier to perform wire bonding on the portion of the first portion 81 that is exposed from the covering member 60. The distance L2 is more preferably 200 μm or more, and even more preferably 300 μm or more. The distance L2 is, for example, 1000 μm or less. Note that the distance L2 is the distance in a direction parallel to the upper surface 11A of the substrate 11.

[0063] The light-emitting device 1 can be used, for example, in the headlights of an automobile. When the light-emitting device 1 is used in the headlights of an automobile, saltwater such as rain or fog containing salt may adhere to it. Even in such cases, the saltwater has difficulty reaching the gold layer 33, so the light-emitting device 1 can operate stably over a long period of time and achieve excellent reliability.

[0064] <Motion-emitting device according to a modified example of the first embodiment> A modified version of the first embodiment will now be described. The modified version of the first embodiment differs from the first embodiment mainly in the shape of the gold layer 33 when viewed from above. Figure 5C is a schematic top view showing the first boundary of the modified version of the first embodiment.

[0065] As shown in Figure 5C, in a modified example of the first embodiment, in the first boundary 86C, which is another example of the first boundary 86, the edge of the gold layer 33 that overlaps with the aluminum layer 32 in a top view is wavy. That is, in a top view, the first boundary 86C includes one or more curved portions 86c. In a top view, the curved portions 86c included in the first boundary 86C include a point away from the straight portion 86b connecting the two intersection points of the first boundary 86B and the contour of the aluminum layer 32, as shown in Figure 5B, and are longer than the straight portion 86b.

[0066] In the modified version of the first embodiment, the gold layer 33 and the first conductive layer 31 are in contact over a larger area than in the first embodiment, and consequently, the first conductive layer 31 and the aluminum layer 32 are in contact over a larger area than in the first embodiment. Therefore, the risk of disconnection between the gold layer 33 and the aluminum layer 32 can be reduced, and the reliability of the connection can be improved.

[0067] <Method for manufacturing a light-emitting device according to the first embodiment> A method for manufacturing the light-emitting device according to the first embodiment will be described. First, a method for manufacturing the substrate 10 will be described. Figures 6A to 6G are cross-sectional views showing a method for manufacturing the substrate included in the light-emitting device according to the first embodiment.

[0068] First, as shown in Figure 6A, a substrate 11 is prepared, and a second conductive layer 34 is placed on the upper surface 11A of the substrate 11. In the process of placing the second conductive layer 34, a first layer 41 containing a nickel-chromium alloy is placed on the upper surface 11A of the substrate 11, and a seed layer 42 containing gold is placed on the upper surface of the first layer 41. When the first layer 41 contains a nickel-chromium alloy, the first layer 41 and the seed layer 42 are preferably placed by sputtering. When the first layer 41 and the seed layer 42 are placed by sputtering, the heating temperature of the sputtering method is high, and a film can be formed with strong energy. When the first layer 41 and the seed layer 42 are placed by sputtering, there is a tendency for irregularities to be formed on the surface of the first layer 41, but the seed layer 42 fills in the irregularities, and the surface of the seed layer 42 becomes substantially flat.

[0069] Next, as shown in Figure 6B, a step is performed to place the mask 110 on the seed layer 42. The mask 110 has openings 111 in the region where the conductive member 12 is to be formed. The mask 110 is, for example, a photoresist.

[0070] The mask 110 is not particularly limited and can be formed using photoresist compositions, sheet-type resists (dry film resists), etc., that are commonly used in the field of light-emitting devices. Specifically, the mask 110 can be a photoresist composition made of various materials classified as novolac-diazonaphthoquinone (DNQ)-based photoresists, positive-type photoresists, negative-type photoresists, chemically amplified photoresists, photocrosslinked photoresists, photopolymerized photoresists, etc., or a dry film resist formed from these photoresist compositions. Any commercially available photoresist composition or dry film resist can be used. Among these, it is preferable to form the mask 110 using a negative-type photoresist.

[0071] Methods for forming the mask 110 using a photoresist composition include, for example, screen coating, spin coating, roll coating, laminating, dip coating, and spray coating.

[0072] Next, the mask 110 can be formed into a predetermined shape, for example, by using photolithography and etching methods. When using a negative type photoresist, for example, exposure is performed using a mask 110 having an opening of a desired shape according to the opening 111.

[0073] There are no particular restrictions on the exposure dose, but it is preferable to set it appropriately within the range of approximately 10 mJ to 50 mJ. Baking may be performed at any temperature and time before or after exposure.

[0074] Subsequently, the mask 110 is patterned into a predetermined shape by immersion development or spray development using a developer that dissolves the resist present in the unexposed areas of the mask 110.

[0075] The developer used here can be appropriately selected depending on the type of resist being used. Examples include tetramethylammonium hydroxide (TMAH) and tetrabutylammonium hydroxide (TBAH).

[0076] Next, as shown in Figure 6C, a step is performed to place the gold layer 33 on the seed layer 42 inside the opening 111. The gold layer 33 can be placed by electroplating or vapor deposition. With electroplating, the film deposition rate is fast, so a gold layer 33 of several μm can be easily placed. After placing the gold layer 33, the mask 110 is removed. The first boundary 86, which includes a straight section 86b or a curved section 86c, can be placed in the step of placing the gold layer 33 by exposing the mask 110 so that it has an opening 111 with a shape corresponding to the straight section 86b or the curved section 86c.

[0077] Next, as shown in Figure 6D, a step is performed to remove the portion of the second conductive layer 34 that is exposed from the gold layer 33. Of the portions of the second conductive layer 34 that are exposed from the gold layer 33, the seed layer 42 and the first layer 41 can be removed by wet etching. When the first layer 41 is removed, a part of the outer edge of the first layer 41 that overlaps with the gold layer 33 in a top view is also removed, so a part of the underside of the seed layer 42 is exposed. This wet etching is sometimes called flash etching. This wet etching prevents adjacent wiring from being electrically connected through the second conductive layer 34 that is exposed from the gold layer 33. Therefore, insulation can be ensured between the gold layers 33 of adjacent wiring. In this way, when it is desired to ensure sufficient insulation of the wiring on the substrate 11, the side etching of the first layer 41 is performed under conditions that facilitate its progress. As a result, in a top view, the end 41A of the first layer 41 is located inward from the end of the gold layer 33 and the end 42A of the seed layer 42, and a gap is formed between the substrate 11 and the seed layer 42. In a top view, the distance between the edge 41A of the first layer 41 and the edge 42A of the seed layer 42 is greater than 0 μm and less than 10 μm.

[0078] Next, as shown in Figure 6E, a step is performed to place the first conductive layer 31 and the aluminum layer 32 on the substrate 11 and the gold layer 33. The first conductive layer 31 can be placed by sputtering or the like, and the aluminum layer 32 can be placed by sputtering or vapor deposition or the like.

[0079] Because the distance between the upper surface 11A of the substrate 11 and the lower surface of the seed layer 42 is small, when the first conductive layer 31 is placed by sputtering or the like, the sputtered particles forming the first conductive layer 31 have difficulty wrapping around enough to fill the gap between the substrate 11 and the seed layer 42. As a result, a void 43 is formed between the substrate 11 and the seed layer 42. If the thickness of the first conductive layer 31 is greater than or equal to the thickness of the first layer 41, the film of the first conductive layer 31 is continuous near the first boundary 86, so the void 43 is a space surrounded by the first conductive layer 31, the first layer 41, the seed layer 42, and the substrate 11. If the thickness of the first conductive layer 31 is less than the thickness of the first layer 41, there is a possibility that a break may occur near the first boundary 86 due to insufficient film formation of the first conductive layer 31. If a break occurs due to insufficient deposition of the first conductive layer 31, the void 43 is a space surrounded by the aluminum layer 32, the first conductive layer 31, the first layer 41, the seed layer 42, and the substrate 11.

[0080] Next, as shown in Figure 6F, a mask 120 is placed on the aluminum layer 32. The mask 120 covers the areas of the first conductive layer 31 and the aluminum layer 32 that are to be left intact, and has openings 121 in the remaining areas. The mask 120 is, for example, a photoresist similar to that described above.

[0081] Next, as shown in Figure 6G, the portions of the aluminum layer 32 and the first conductive layer 31 exposed from the mask 120 are removed. As a result, the gold layer 33 is exposed from the aluminum layer 32 and the first conductive layer 31 in the region where the second portion 82 of the conductive member 12 is to be formed. The portions of the aluminum layer 32 and the first conductive layer 31 exposed from the mask 120 can be removed by wet etching. Then, the mask 120 is removed.

[0082] In this case, if the covering member 60 covers only at least a portion of the conductive member 12 without contacting the light-emitting element 20, the uncured resin is printed, applied by dispensing, or bonded in sheet form to the upper surface 11A of the substrate 11, and then cured. This makes possible a substrate 10 equipped with the covering member 60.

[0083] In this way, a substrate 10 having a base body 11 and a conductive member 12 can be manufactured.

[0084] A light-emitting device is manufactured using the substrate 10. Figures 7A to 7C and 7E are partial cross-sectional views illustrating the manufacturing process of the light-emitting device according to the first embodiment. Figure 7D is a top view illustrating the manufacturing process of the light-emitting device according to the first embodiment.

[0085] First, as shown in Figure 7A, a light-emitting element 20 having an upper surface 20a, a lower surface 20b, and a plurality of side surfaces 20c connected to the upper surface 20a and the lower surface 20b, and a substrate 10 are prepared. In the example shown in Figure 7A, multiple light-emitting elements 20 are prepared. Then, as shown in Figure 7B, the plurality of light-emitting elements 20 are arranged on the substrate 10. Each light-emitting element 20 is flip-chip mounted on the substrate 10 via a gold bump which is a conductive bonding member 25, with the side on which the electrodes are placed facing the conductive member 12.

[0086] Next, the light-transmitting member 50 is placed on top of the light-emitting element 20. In the example shown in Figure 7C, one light-transmitting member 50 is placed on top of each of the multiple light-emitting elements 20. In the first embodiment, the light-transmitting member 50 is placed on the upper surface 20a of the light-emitting element 20 via an adhesive resin. Alternatively, the light-transmitting member 50 may be placed on the upper surface of the light-emitting element 20 by direct bonding methods such as compression bonding, surface activation bonding, atomic diffusion bonding, or hydroxyl group bonding, without using a bonding member such as an adhesive resin. In this embodiment, a protective element 4 is placed next to each light-emitting element 20.

[0087] Next, a covering member 60 is placed on the substrate 10 to cover the side surfaces 50c of each light-transmitting member 50 and the side surfaces 20c of each light-emitting element 20 together. Specifically, the uncured resin that will become the covering member 60 is placed using a dispenser. In Figure 7D, only the external connection portion 12a of the conductive member 12 is shown, and the wiring pattern extending from the external connection portion 12a onto the base body 11 is omitted. In Figure 7D, boundary lines BD1, BD2, and BD3, which are imaginary lines that demarcate the areas where multiple light-emitting devices 1 are to be formed, are shown as dashed lines. Figure 7D shows an excerpt of a portion of the substrate 10 before it is separated into individual pieces.

[0088] In this embodiment, eight light-emitting elements 20 and eight protective elements 4 are mounted in each planned area for the formation of a light-emitting device, which is demarcated by boundary lines BD1, BD2, and BD3. Here, boundary lines BD1 and BD2 are imaginary lines that demarcate the longitudinal direction of the planned area for the formation of a light-emitting device, and boundary line BD3 is an imaginary line that demarcates the short direction of the planned area for the formation of a light-emitting device. As shown by the placement of the external connection portion 12a of the conductive member 12, the planned areas for the formation of light-emitting devices, which are arranged in the short direction (vertical direction in Figure 7D), are arranged so that the orientation in the vertical direction alternates for each row. In other words, in this embodiment, the planned areas for the formation of light-emitting devices are arranged to be approximately symmetrical with respect to boundary line BD2 as the axis of symmetry in a plan view. For this reason, the light-emitting elements 20 are arranged on the substrate 10 to be approximately symmetrical with respect to boundary line BD2 as the axis of symmetry.

[0089] In the planned formation area of ​​each light-emitting device, eight light-emitting elements 20, which have a roughly square shape when viewed from above, are arranged in a single row along the longitudinal direction, approximately in the center along the short side. The eight protective elements 4 are positioned approximately in the center of each light-emitting element 20 along the longitudinal direction (horizontal direction in Figure 7D), and on the side opposite to the side of each light-emitting element 20 from which the external connection portion 12a is provided along the short side (vertical direction in Figure 7D).

[0090] First, as shown in Figure 7D, uncured resin is arranged to form a roughly rectangular frame surrounding the multiple light-emitting elements 20 in a top view. At this time, a roughly rectangular first convex member 61 is formed from the uncured resin so as to include the outer edge of the first region 91 (i.e., the region that will become the outer edge of the covering member 60). Next, a second convex member 62 overlapping the boundary lines BD2 and BD3 is formed from the uncured resin. The second convex member 62 includes a second convex member 62a overlapping the boundary line BD2 and a second convex member 62b overlapping the boundary line BD3. Then, as shown in Figure 7E, uncured resin is arranged near the outer periphery of the multiple light-emitting elements 20. At this time, the uncured resin spreads by capillary action to cover the lower surface 20b of the light-emitting elements 20 and the conductive bonding member 25. Then, the uncured resin is arranged to cover the side surfaces 50c of each light-transmitting member 50 and the side surfaces 20c of each light-emitting element 20. At this time, the amount of uncured resin is adjusted so that the upper surface of the uncured resin covering the side surface 20c of the light-emitting element 20 and the upper surface 50a of the light-transmitting member 50 are substantially the same plane. Then, the uncured resin is cured to form the covering member 60. As a result, as shown in Figure 5A, a substrate 10 is formed which includes a first region 91 on which the covering member 60 is placed and a second region exposed from the covering member 60. Finally, as shown in Figures 1 and 2, the substrate 10 and the covering member 60 are cut along boundary lines BD2 and BD3 with a dicer to obtain individual light-emitting devices 1 that contain a desired number of light-emitting elements 20.

[0091] In this way, the light-emitting device 1 according to the first embodiment can be manufactured.

[0092] <Light-emitting device according to the second embodiment> A second embodiment will now be described. The second embodiment differs from the first embodiment mainly in the configuration of the substrate. Figure 8 is a schematic cross-sectional view showing the substrate constituting the light-emitting device according to the second embodiment, and corresponds to the cross-sectional view along the VV line in Figure 2.

[0093] As shown in Figure 8, the light-emitting device according to the second embodiment has a substrate 15 instead of substrate 10. In substrate 10, the second conductive layer 34 is arranged only in the second portion 82 and the third portion 83, whereas in substrate 15, the second conductive layer 34 is arranged not only in the second portion 82 and the third portion 83 but also in a part of the first portion 81. That is, the end 41A of the first layer 41 is located in the first portion 81. In the second embodiment, the end 42A of the seed layer 42 is also located in the first portion 81. The first conductive layer 31 is in contact with the first layer 41 and the seed layer 42.

[0094] In the second embodiment, the substrate 15 does not have a gap 43 because the first conductive layer 31 and the first layer 41 are in contact. This reduces the occurrence of interruptions due to insufficient film deposition of the first conductive layer 31 near the first boundary 86, regardless of the thickness of the first conductive layer 31, and makes it easier to obtain film continuity. Therefore, it is highly effective in reducing the occurrence of galvanic corrosion.

[0095] The other components of the substrate 15 are the same as those of the substrate 10. Also, in the second embodiment, similar to the modification of the first embodiment, the first boundary 86 may have a shape that includes one or more curved portions 86c when viewed from above.

[0096] <Manufacturing method for a light-emitting device according to the second embodiment> A method for manufacturing the light-emitting device according to the second embodiment will be described. First, the method for manufacturing the substrate 15 will be described. Figures 9A to 9E are cross-sectional views showing the method for manufacturing the substrate included in the light-emitting device according to the second embodiment.

[0097] First, as shown in FIG. 9A, a substrate 11 is prepared, and a step of disposing a mask 210 on the substrate 11 is performed. The mask 210 is mainly different in cross-sectional shape from the mask 110. The mask 210 is formed such that its cross-sectional shape is an overhang shape (also referred to as a tapered shape). That is, the mask 210 is formed such that in a cross-sectional view of the mask 210, the width in the cross-sectional view of the mask 210 (the length in the direction parallel to the upper surface 11A of the substrate 11) decreases from the upper surface of the mask 210 toward the lower surface of the mask 210. FIG. 10 is an enlarged cross-sectional view of the region X in FIG. 9A. In the region X, on the upper surface 11A of the substrate 11, there are a region M and a region N adjacent to the region M. The mask 210 is formed using a liquid photoresist. In the step of disposing the mask 210, the photoresist is exposed and developed such that the mask 210 has a main portion 211 that contacts the upper surface 11A of the region M and a protruding portion 212 that protrudes onto the region N from the main portion without contacting the upper surface 11A of the region N. The maximum width in the direction parallel to the upper surface 11A of the substrate 11 of the protruding portion 212 that protrudes onto the region N is 1 μm or more and 5 μm or less. As a result, a region 215 is formed between the upper surface 11A and the side surface (inclined surface) of the protruding portion 212, or in other words, below the protruding portion 212.

[0098] By exposing and developing the photoresist, a mask 210 is formed in which the length of the lower surface of the mask 210 (hereinafter referred to as L1) in the cross-section in the thickness direction of the substrate 11 is shorter than the length of the upper surface of the mask 210 (hereinafter referred to as L2). That is, the length of the lower surface (L1) of the mask 210 and the length of the upper surface (L2) of the mask 210 satisfy L1 < L2.

[0099] Next, as shown in Figure 9B, the second conductive layer 34 is placed on the substrate 11 and the mask 210. The second conductive layer 34 can be placed in the same manner as in the first embodiment. The thickness of the mask 210 is thin, only a few μm from the upper surface 11A of the substrate 11. Therefore, in the process of placing the second conductive layer 34 on the substrate 11 and the mask 210, the material of the second conductive layer 34 wraps around not only the upper surface 11A of the substrate 11 and the upper surface of the mask 210, but also the side surface (inclined surface) of the protrusion 212, and the second conductive layer 34 is placed in region 215 with a moderately thin thickness. As a result, region 215A is formed along the upper surface 11A of the substrate 11 and the side surface (inclined surface) of the protrusion 212. The "moderately thin thickness of the second conductive layer 34" as described here means that the thickness of the second conductive layer 34, which is positioned on the side surface of the protrusion 212, is such that it is thick enough to form the gold layer 33 by electroplating in the process of positioning the gold layer 33 on the seed layer 42 inside the opening 221 described later, and is thin enough to remove the second conductive layer 34 positioned on the side surface of the protrusion 212 in the process of removing a part of the second conductive layer 34, the mask 210 and the mask 220 described later. The thickness of the second conductive layer 34 positioned on the side surface of the protrusion 212 is preferably, for example, 0.001 μm or more and 0.1 μm or less.

[0100] Next, as shown in Figure 9C, the mask 220 is placed on the second conductive layer 34. The mask 220 has an opening 221 in the region where the conductive member 12 is to be formed. The mask 220 is formed using a dry film photoresist. The mask 220 is formed such that, in a top view, the outer edge of the mask 220 is located outside the outer edge of the mask 210, so that the mask 210 is not exposed from the mask 220. For example, in a top view, the distance between the outer edge of the mask 220 and the outer edge of the mask 210 is 3 μm or more and 8 μm or less. When using a dry film, vacuuming removes the air between the mask 210 and the second conductive layer 34 and the mask 220, and also allows the mask 220 to be placed in region 215A. Alternatively, a liquid resist can be used instead of a dry film for the mask 210. In the process of placing the mask 220, the photoresist is exposed and developed so that the photoresist placed on the upper surface of the second conductive layer 34 and the photoresist placed on the side surface of the second conductive layer 34 in region 215A remain. As a result, the second conductive layer 34 placed on the upper surface 11A is exposed from the mask 220.

[0101] Next, as shown in Figure 9D, the gold layer 33 is placed on top of the seed layer 42 inside the opening 221. The gold layer 33 can be placed in the same manner as in the first embodiment. At this time, the first layer 41 and the seed layer 42 are placed in region 215, and the mask 220 is placed in region 215A, so the gold layer 33 is not formed in the regions where regions 215 and 215A were located. In addition, by positioning the mask 210 so that it is not exposed from the mask 220, the shape of the edges of the gold layer 33 can be adjusted.

[0102] Next, as shown in Figure 9E, a step is performed to remove a portion of the second conductive layer 34, mask 210, and mask 220. In this step, mask 210, the second conductive layer 34 located on the upper surface of mask 210, the second conductive layer 34 located on the side of mask 210 (in other words, the side of the protruding portion 212), mask 220 located on top of mask 210, and mask 220 located in region 215A are removed.

[0103] Subsequently, in the same manner as in the first embodiment, the process of placing the first conductive layer 31 and the aluminum layer 32 on the substrate 11 and the gold layer 33, and the subsequent processes (see Figures 6E to 6G) are carried out. In this way, the substrate 15 can be manufactured.

[0104] Subsequently, by using substrate 15 instead of substrate 10 and performing the same steps as in the first embodiment (see Figures 7A to 7E), the light-emitting device according to the second embodiment can be manufactured.

[0105] Although preferred embodiments have been described in detail above, the invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims.

[0106] In addition to the embodiments described above, the following further notes are disclosed. (Note 1) A substrate having a main surface, A conductive member disposed on the main surface, Covering member and Equipped with, The conductive member is A first portion having a first conductive layer and an aluminum layer stacked in order from bottom to top, The second part has a gold layer on its uppermost surface, A third portion having the gold layer, the first conductive layer, and the aluminum layer stacked in order from bottom to top, It has, A substrate, the first boundary which is the boundary between the first part and the third part, and the second boundary which is the boundary between the second part and the third part, are covered by the covering member. (Note 2) The substrate as described in Appendix 1, wherein the ionization tendency of the first conductive layer is lower than that of the aluminum layer. (Note 3) The substrate includes a nitride ceramic, The conductive member has a second conductive layer between the gold layer and the substrate. The substrate according to Appendix 1 or Appendix 2, wherein the second conductive layer has a first layer containing nickel and chromium. (Note 4) The first conductive layer comprises at least one of titanium or ruthenium. The substrate according to Appendix 3, wherein a gap is provided between the first conductive layer and the first layer. (Note 5) The substrate according to Appendix 4, wherein the end of the first layer is located in the third portion. (Note 6) The substrate according to Appendix 3, wherein the end of the first layer is located in the first portion. (Note 7) The substrate according to any one of the appendices 3 to 6, wherein the thickness of the first conductive layer is thinner than the thickness of the second conductive layer. (Note 8) The substrate includes a nitride ceramic, The first conductive layer comprises at least one of titanium or ruthenium. A substrate according to any one of Appendix 1 to Appendix 7, wherein the first conductive layer and the substrate are in contact with each other. (Note 9) The substrate according to any one of the appendices 1 to 8, wherein the thickness of the third portion is greater than the thickness at the outer edge of the first portion and the thickness of the second portion. (Note 10) A substrate according to any one of the appendices 1 to 9, wherein, in a top view, the area of ​​the third portion is smaller than the area of ​​the first portion. (Note 11) The main surface of the substrate is The first region on which the covering member is arranged, The second region exposed from the covering member, It has, The substrate according to any one of the appendices 1 to 8, wherein the distance between the third boundary, which is the boundary between the first region and the second region, and the first boundary is 10 μm or more. (Note 12) The substrate as described in Appendix 11, wherein, in a top view, the distance from the third boundary to the outer edge of the first portion is 100 μm or more. (Note 13) A substrate according to any one of Appendix 1 to Appendix 12, wherein, in a top view, the first boundary includes a curved portion. (Note 14) A light-emitting device comprising a substrate described in any one of Appendix 1 to Appendix 13 and a light-emitting element, The light-emitting element is connected to the gold layer in the second portion, and is a light-emitting device. (Note 15) The covering member covers the light-emitting device as described in Appendix 14. (Note 16) A substrate having a main surface, A conductive member disposed on the main surface, Equipped with, The conductive member is A first portion having a first conductive layer and an aluminum layer stacked in order from bottom to top, The second part has a gold layer on its uppermost surface, A third portion having the gold layer, the first conductive layer, and the aluminum layer stacked in order from bottom to top, It has, The conductive member has a second conductive layer, which includes a first layer, between the gold layer and the substrate. A substrate in which a gap is disposed between the first conductive layer and the first layer. (Note 17) The substrate according to Appendix 16, wherein the end of the first layer is located in the third portion. (Note 18) A light-emitting device comprising a substrate as described in Appendix 16 or Appendix 17 and a light-emitting element, The light-emitting element is connected to the gold layer in the second portion, and is a light-emitting device. [Explanation of Symbols]

[0107] 1. Light-emitting device 4. Protective elements 10, 15 circuit boards 11 Base 11A Top 12 Conductive members 12a External connection section 20 Light-emitting elements 31 First conductive layer 32 Aluminum layer 33 gold layer 34 Second conductive layer 41 1st layer 41A End of the first layer 42 Seed Layer 42A End of seed layer 43 void 50 Translucent material 60 Covering member 81 Part 1 82 Part 2 83 Part 3 86, 86B, 86C 1st boundary 86b Straight section 86c curved section 87 Second boundary 91 1st area 92 Second area 93 Third boundary 110, 120, 210, 220 masks

Claims

1. A substrate having a main surface, A conductive member disposed on the main surface, Covering member and Equipped with, The conductive member is A first portion having a first conductive layer and an aluminum layer stacked in order from bottom to top, The second part has a gold layer on its uppermost surface, A third portion having the gold layer, the first conductive layer, and the aluminum layer stacked in order from bottom to top, It has, A substrate, wherein the first boundary, which is the boundary between the first part and the third part, and the second boundary, which is the boundary between the second part and the third part, are covered by the covering member.

2. The substrate according to claim 1, wherein the ionization tendency of the first conductive layer is lower than that of the aluminum layer.

3. The substrate includes a nitride ceramic, The conductive member has a second conductive layer between the gold layer and the substrate. The substrate according to claim 1 or claim 2, wherein the second conductive layer has a first layer containing nickel and chromium.

4. The first conductive layer comprises at least one of titanium or ruthenium. The substrate according to claim 3, wherein a gap is provided between the first conductive layer and the first layer.

5. The substrate according to claim 4, wherein the end of the first layer is located in the third portion.

6. The substrate according to claim 3, wherein the end of the first layer is located in the first portion.

7. The substrate according to claim 3, wherein the thickness of the first conductive layer is thinner than the thickness of the second conductive layer.

8. The substrate includes a nitride ceramic, The first conductive layer comprises at least one of titanium or ruthenium. The substrate according to claim 1 or claim 2, wherein the first conductive layer and the substrate are in contact with each other.

9. The substrate according to claim 1 or claim 2, wherein the thickness of the third portion is greater than the thickness at the outer edge of the first portion and the thickness of the second portion.

10. The substrate according to claim 1 or claim 2, wherein, in a top view, the area of ​​the third portion is smaller than the area of ​​the first portion.

11. The main surface of the substrate is The first region on which the covering member is arranged, The second region exposed from the covering member, It has, The substrate according to claim 1 or claim 2, wherein the distance between the third boundary, which is the boundary between the first region and the second region, and the first boundary is 10 μm or more.

12. The substrate according to claim 11, wherein, in a top view, the distance from the third boundary to the outer edge of the first portion is 100 μm or more.

13. The substrate according to claim 1 or claim 2, wherein, in a top view, the first boundary includes a curved portion.

14. A light-emitting device comprising a substrate according to claim 1 or claim 2 and a light-emitting element, The light-emitting element is connected to the gold layer in the second portion, and is a light-emitting device.

15. The light-emitting device according to claim 14, wherein the covering member covers the light-emitting element.

16. A substrate having a main surface, A conductive member disposed on the main surface, Equipped with, The conductive member is A first portion having a first conductive layer and an aluminum layer stacked in order from bottom to top, The second part has a gold layer on its uppermost surface, A third portion having the gold layer, the first conductive layer, and the aluminum layer stacked in order from bottom to top, It has, The conductive member has a second conductive layer, which includes a first layer, between the gold layer and the substrate. A substrate in which a gap is provided between the first conductive layer and the first layer.

17. The substrate according to claim 16, wherein the end of the first layer is located in the third portion.

18. A light-emitting device comprising a substrate according to claim 16 or claim 17 and a light-emitting element, The light-emitting element is connected to the gold layer in the second portion, and is a light-emitting device.

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