Method for manufacturing a light-emitting device

Abstract

The present invention provides a method for manufacturing a light-emitting device that can improve reliability. [Solution] A method for manufacturing a light-emitting device includes the steps of: preparing a package having an upper surface with a recess and a lower surface opposite to the upper surface, and having a through hole in the inner surface defining the recess that penetrates from the inner surface to the lower surface; arranging a light-emitting element on the inner surface away from the through hole; arranging a light-reflecting member on the inner surface away from the light-emitting element and the through hole; closing the opening of the recess by arranging a lid member on the upper surface via a bonding member; removing any deposits adhering to the light-reflecting member from the through hole after the closing of the opening; and hermetically sealing the light-emitting element by blocking the through hole after the removal step.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a light-emitting device.

Background Art

[0002] It is known to hermetically seal the inside of a package by closing a through hole disposed on the bottom surface of the package (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to provide a method for manufacturing a light-emitting device that can improve reliability in a light-emitting device that hermetically seals the inside of a package.

Means for Solving the Problems

[0005] According to an embodiment of the present disclosure, a method for manufacturing a light-emitting device includes: preparing a package having an upper surface having a recess and a lower surface opposite to the upper surface and having a through hole penetrating from the inner surface defining the recess to the lower surface; disposing a light-emitting element on the inner surface away from the through hole; disposing a light-reflecting member on the inner surface away from the light-emitting element and the through hole; closing the opening of the recess by disposing a lid member via a joining member on the upper surface; after the step of closing the opening, removing an attachment adhering to the light-reflecting member from the through hole; and after the removing step, hermetically sealing the light-emitting element by closing the through hole.

Effects of the Invention

[0006] According to this disclosure, it is possible to provide a method for manufacturing a light-emitting device that can improve reliability. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic top view of the light-emitting device in the first embodiment. [Figure 2] This is a schematic bottom view of the light-emitting device in the first embodiment. [Figure 3] Figures 1 and 2 show schematic cross-sectional views along line III-III. [Figure 4] Figures 1 and 2 show schematic cross-sectional views along the line IV-IV. [Figure 5] This is a schematic cross-sectional view of the light-reflecting member in the first embodiment. [Figure 6] This figure shows the results of measuring the concentrations of each gas before and after operation in sample A, which does not have a light-reflecting member. [Figure 7] This figure shows the results of measuring the concentrations of each gas before and after operation in sample B, which has a light-reflecting member. [Figure 8A] This is a schematic cross-sectional view showing the manufacturing method of the first embodiment. [Figure 8B] This is a schematic cross-sectional view showing the manufacturing method of the first embodiment. [Figure 9A] This is a schematic cross-sectional view showing the manufacturing method of the first embodiment. [Figure 9B] This is a schematic cross-sectional view showing the manufacturing method of the first embodiment. [Figure 9C] This is a schematic cross-sectional view showing the manufacturing method of the first embodiment. [Figure 10A] This is a schematic cross-sectional view showing the manufacturing method of the first embodiment. [Figure 10B] This is a schematic cross-sectional view showing the manufacturing method of the first embodiment. [Figure 11A] This is a schematic plan view showing the manufacturing method of the light-emitting device in the first embodiment. [Figure 11B] This is a schematic plan view showing the manufacturing method of the light-emitting device in the first embodiment. [Figure 11C]It is a schematic plan view showing a method of manufacturing a light-emitting device according to the first embodiment.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the present disclosure will be described in detail with reference to the drawings. The following embodiments are examples for embodying the technical idea of the invention, and do not limit the present disclosure to the described configurations and numerical values. In the following description, terms indicating a specific direction or position (for example, "up", "down", and other terms including those terms) are used as necessary. However, the use of those terms is for facilitating the understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meanings of those terms. Also, in each drawing, the same reference numerals are given to the same components, and redundant descriptions may be omitted as appropriate. The sizes, positional relationships, etc. of each member shown in each drawing may be exaggerated for facilitating the understanding of the invention. Furthermore, an end view showing a cut surface may be used as a cross-sectional view.

[0009] In each drawing, as a direction expression, a rectangular coordinate having an X-axis, a Y-axis, and a Z-axis is used. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The direction in which the arrow points in the X direction is the +X side, + The opposite side of the +X side is denoted as the -X side. The direction in which the arrow points in the Y direction is the +Y side, and the opposite side of the +Y side is denoted as the -Y side. The direction in which the arrow points in the Z direction is the +Z side, and the opposite side of the +Z side is - denoted as the -Z side. A plan view means looking at the object from the +Z side.

[0010] (First Embodiment) A light-emitting device 100 manufactured by the manufacturing method according to the first embodiment will be described. As shown in FIGS. 1 to 4, the light-emitting device 100 includes a package 10, a light-emitting element 12, a light reflection member 14, a lid member 20, and a metal member 29. FIGS. 1 and 2 are schematic plan views of the light-emitting device 100 in the first embodiment. FIG. 1 is a schematic top view of the light-emitting device 100 with the lid member 20 removed. FIG. 2 is a schematic bottom view of the package 10. FIG. 3 is a schematic cross-sectional view taken along line III-III of FIGS. 1 and 2. FIG. 3 is a schematic cross-sectional view taken along line IV-IV of FIGS. 1 and 2.

[0011] The package 10 has an upper surface 10A and a lower surface 10B. The upper surface 10A is the + surface in the Z direction, and the lower surface 10B is the - surface in the Z direction. The package 10 has a recess 11 in the upper surface 10A. The inner surface 11C of the recess 11 is a bottom surface 11A and a side surface 11B. The package 10 has a bottom portion having the bottom surface 11A and a side portion having the side surface 11B. The bottom portion and the side portion may be formed of an integral member or may be formed of separate members. The light-emitting element 12 is disposed on the bottom surface 11A. The light reflection member 14 is disposed over the bottom surface 11A and the side surface 11B so as to surround the light-emitting element 12 in a top view.

[0012] The package 10 has a recess 11 in the upper surface, and the inner surface 11C defining the recess 11 has through holes 16 penetrating from the inner surface 11C of the recess 11 to the lower surface 10B. Two through holes 16 are disposed so as to sandwich the light-emitting element 12 in the X direction. The package 10 further has a metal film 28 disposed from the inner surface 16A of the through hole 16 to the lower surface 10B of the package 10. In the light-emitting device 100, the metal member 29 is disposed in contact with the metal film 28 and closes the through hole 16.

[0013] Package 10 has wiring 24A and wiring 24B. In package 10, it is preferable that the through hole 16 is located away from wiring 24A and wiring 24B. By separating the through hole 16 from wiring 24A and wiring 24B that supply power to the light-emitting element 12, the through hole 16 can be positioned near the light-emitting element 12. Package 10 has at least one through hole 16. It is preferable that package 10 has multiple through holes 16. This allows for efficient depressurization of the internal space 18 and supply of gas in the removal and / or hermetically sealing process described later.

[0014] Wires 24A and 24B are arranged on the bottom surface 11A of the recess 11, spaced apart from each other. The light-emitting element 12 is flip-chip mounted on wires 24A and 24B via conductive members 25A and 25B. Package 10 has external connection terminals 26A and 26B on its bottom surface 10B. External connection terminals 26A and 26B are arranged on the bottom surface 10B of package 10, spaced apart from each other. External connection terminals 26A and 26B are electrically connected to wires 24A and 24B, respectively, via vias (not shown) that penetrate the bottom of package 10. The protective element 13 is electrically connected to wires 24A and 24B of package 10, for example, via a wire.

[0015] The light-emitting device 100 includes a light-reflecting member 14 disposed within a recess 11 of the package 10. The light-reflecting member 14 is positioned on the bottom of the recess 11, including over the wirings 24A and 24B, so as to surround the light-emitting element 12 in a top view. If the light-emitting device 100 includes a protective element 13, it is preferable that the light-reflecting member 14 be positioned on the protective element 13. The through-hole 16 is positioned away from the light-emitting element 12, the light-reflecting member 14, the wirings 24A and 24B, and connects to the internal space 18 of the recess 11. The through-hole 16 is positioned between the wirings 24A and 24B in the Y direction, and between the external connection terminals 26A and 26B. The metal film 28 is electrically isolated from the wirings 24A and 24B, the external connection terminals 26A and 26B.

[0016] The light-emitting device 100 includes a lid member 20 that closes the opening of the package 10. The lid member 20 includes a plate-shaped translucent member 20A. The lid member 20 may further include an optical film such as an anti-reflective film 20B. Here, the anti-reflective film 20B is arranged on the upper and lower surfaces of the translucent member 20A. The lid member 20 is joined to the upper surface 10A of the package 10 via a bonding member 22. Metal films 22A and 22B are arranged on the upper surface 10A of the package 10 and the lower surface of the lid member 20. The bonding member 22 is joined to the metal films 22A and 22B. The light-emitting device 100, with the package 10, the lid member 20 and the metal member 29, can hermetically seal the light-emitting element 12 within the internal space 18.

[0017] When a voltage is applied between the external connection terminals 26A and 26B from the bottom surface 10B of the package 10, a voltage or current is applied to the electrodes of the light-emitting element 12 via the wiring 24A, wiring 24B, conductive members 25A and 25B. As a result, the light-emitting element 12 emits light. Of the light emitted by the light-emitting element 12, the light traveling in the +Z direction passes through the lid member 20 and is emitted outside the package 10. Of the light emitted by the light-emitting element 12, the light traveling in the X and Y directions is reflected by the light-reflecting member 14 and passes through the lid member 20 and is emitted outside the package 10. By arranging the light-reflecting member 14 across the bottom surface 11A and the side surface 11B and tilting the side surface of the light-reflecting member 14, the light emitted by the light-emitting element 12 in the X and Y directions can be efficiently reflected towards the lid member 20. By providing the light-reflecting member 14, the output of the light emitted from the light-emitting device 100 can be increased by, for example, 20%.

[0018] The protective element 13 is positioned on the bottom of the recess 11 and is connected in parallel with the light-emitting element 12 to the wirings 24A and 24B. The protective element 13 protects the light-emitting element 12 from surge currents or static electricity. The protective element 13 is, for example, a Zener diode. Note that the light-emitting device 100 does not necessarily have to be equipped with the protective element 13.

[0019] The light-emitting element 12 is a semiconductor light-emitting element such as an LED (Light Emitting Diode). The peak wavelength of the light-emitting element 12 is, for example, in the range of 260 nm to 630 nm. As an example, the light-emitting element 12 emits ultraviolet light having a peak wavelength of 280 nm to 380 nm. The light-emitting element 12 has a substrate and a semiconductor structure provided on the substrate. The substrate is, for example, a sapphire substrate. The semiconductor structure is, for example, a nitride-based semiconductor (In X Al Y Ga 1-X-Y Use N (where 0 ≤ X, 0 ≤ Y, and X + Y ≤ 1).

[0020] Package 10 includes a substrate on which wiring 24A and wiring 24B are arranged. The substrate is made of an insulating material that does not easily transmit light emitted by the light-emitting element 12, and is an inorganic insulator such as ceramics or an organic insulator such as resin. From the viewpoint of heat resistance and reduction of organic matter adhesion, it is preferable that the substrate of package 10 be an inorganic insulator. Examples of inorganic insulators include aluminum nitride, aluminum oxide, silicon nitride, and mullite. Among these, it is preferable to use aluminum nitride, which has high thermal conductivity, from the viewpoint of releasing the heat generated in the light-emitting element 12.

[0021] Examples of metal components 29 include solders such as tin-bismuth, tin-copper, tin-silver, and gold-tin; eutectic alloys such as alloys mainly composed of gold and tin, alloys mainly composed of gold and silicon, and alloys mainly composed of gold and germanium; and conductive pastes such as silver, gold, and palladium.

[0022] The light-transmitting member 20A is an inorganic material such as sapphire or glass, and is made of a material that transmits light emitted by the light-emitting element 12. The bonding member 22 is a metal member containing tin, such as solder, or a resin such as silicone resin. From the viewpoint of airtightness, it is preferable to use a metal member as the bonding member 22. One example of a bonding member 22 is gold-tin. It is preferable to use materials that have good wettability with the bonding member 22 for the metal films 22A and 22B. When a metal member containing tin is used as the bonding member 22, the outermost surface of the metal films 22A and 22B is, for example, gold or nickel.

[0023] Wiring 24A, Wiring 24B, External connection terminals 26A and 26B are made of a material with high electrical conductivity, such as aluminum, iron, nickel, copper, or alloys containing these materials. Conductive members 25A and 25B are, for example, solder.

[0024] The internal space 18 is filled with a gas containing oxygen. The gas to be filled is, for example, a mixture of oxygen and an inert gas. The inert gas is, for example, nitrogen, helium, neon, argon, krypton, xenon, or a mixture thereof.

[0025] Figure 5 is an enlarged schematic cross-sectional view of the light-reflecting member in the first embodiment. As shown in Figure 5, the light-reflecting member 14 has a light-reflecting material 14A, a support member 14B, and a void 14D. The average particle size of the light-reflecting material 14A is, for example, 0.6 μm or more and 43 μm or less. The light-reflecting material 14A is, for example, plate-shaped. When the light-reflecting material 14A is plate-shaped, the average aspect ratio of the light-reflecting material 14A is, for example, 10 or more and 70 or less. The support member 14B contains particles 14C. The average particle size of the particles 14C is, for example, 0.1 μm or more and 10 μm or less. The aspect ratio of the light-reflecting material 14A is the width in the longitudinal direction relative to the width in the short direction in the SEM image obtained by observing the cross-section of the light-reflecting member 14 using an SEM (Scanning Electron Microscope). The average aspect ratio is the average of the aspect ratios of approximately 100 light-reflecting materials 14A. The particle size is the longitudinal width of the light-reflecting material 14A or the longitudinal width of the particle 14C in the SEM image. The average particle size is the average of the particle sizes of approximately 100 light-reflecting materials 14A or the average of the particle sizes of approximately 100 particles 14C. The light-reflecting member 14 is porous, containing voids 14D as pores. However, the light-reflecting member 14 does not necessarily have to contain voids 14D.

[0026] The light-reflecting material 14A is, for example, particles of at least one of boron nitride and aluminum oxide. The support member 14B contains, for example, an alkali metal such as potassium or sodium. The particle 14C is, for example, silicon oxide. When the light-reflecting material 14A is boron nitride and the particle 14C is silicon oxide, the weight of the light-reflecting material 14A contained in the light-reflecting member 14 is, for example, 1 to 4 times the weight of the particle 14C contained in the light-reflecting member 14.

[0027] The light-reflecting member 14, having the above-described configuration, can efficiently reflect light emitted by the light-emitting element 12 due to the refractive index difference between the light-reflecting material 14A and the particles 14C. Furthermore, the light-reflecting member 14 can maintain a desired shape because the light-reflecting materials 14A are in contact with each other. This reduces the expansion of the light-reflecting member 14 when its temperature rises due to the heat generated in the light-emitting element 12. In the light-emitting device 100, the light-reflecting member 14 only needs to be provided in a portion of the area surrounding the light-emitting element 12.

[0028] (Comparison Form 1) As comparative form 1, a light-emitting device without through holes 16, metal films 28, and metal members 29 was fabricated. The light-emitting element 12 has a semiconductor structure including a sapphire substrate and a nitride-based semiconductor. The light-emitting element 12 emits ultraviolet light. The package 10 includes a substrate made of aluminum nitride. The wiring 24A, wiring 24B, external connection terminals 26A, and external connection terminals 26B are nickel layers and gold layers from the package 10 side. Conductive members 25A and 25B are gold-tin. The light-transmitting member 20A is a sapphire substrate. The bonding member 22 is gold-tin. The internal space 18 is filled with a mixed gas of oxygen and nitrogen. The concentration of oxygen gas in the mixed gas is about 20% by volume.

[0029] For comparison, sample A without the light-reflecting member 14 and sample B with the light-reflecting member 14 were prepared. Before driving the light-emitting element 12 and after driving the light-emitting element 12 for 100 hours, the light-emitting device was destroyed and the gas in the internal space 18 was analyzed.

[0030] Figure 6 shows the results of measuring the concentrations of each gas before and after operation in sample A, which does not have the light-reflecting member 14. As shown in Figure 6, before the light-emitting element 12 is driven, the amount of oxygen (O2) in the internal space 18 is 15.8 volume%, and the amounts of water (H2O) and carbon dioxide (CO2) are 1 volume% or less. After driving the light-emitting element 12 for 100 hours, the amount of oxygen in the internal space 18 is 14.6 volume%, and the amounts of water and carbon dioxide are 1 volume% or less. Thus, the amounts of oxygen, water, and carbon dioxide in the internal space 18 remain almost unchanged before and after operation.

[0031] Figure 7 shows the results of measuring the concentrations of each gas before and after operation in sample B having a light-reflecting member 14. As shown in Figure 7, before operating the light-emitting element 12, the amount of oxygen in the internal space 18 was 14.1 volume%, which is almost the same as in Figure 6. The amounts of water and carbon dioxide were 1.1 volume% or less, which is almost the same as in Figure 6. After operating the light-emitting element 12 for 100 hours, the amount of oxygen in the internal space 18 decreased to 0.6 volume%, and the amounts of water and carbon dioxide increased to 3.4 volume% and 5.8 volume%, respectively.

[0032] As shown in Figure 7, in Sample B, the decrease in oxygen content and increase in water and carbon dioxide content in the internal space 18 after the operation of the light-emitting element 12 is thought to be due to the oxidation of organic matter adhering to the light-reflecting member 14. In light-emitting devices in which the light-emitting element 12 is hermetically sealed, sealing with an oxygen-containing gas can reduce the polymerization and deposition of trace amounts of hydrocarbons inside the package 10 on the light-emitting surface due to photochemical reactions. Therefore, in Sample B, the presence of a large amount of organic matter in the hermetically sealed internal space 18 is thought to have reduced the oxygen concentration in the sealed gas, thereby decreasing the reliability of the light-emitting device.

[0033] The following experiment was conducted to identify the cause of the decreased reliability in Sample B.

[0034] In a sample having a light-reflecting member 14, heating the inside of the recess 11 to 250°C in an oxygen atmosphere and then placing the lid member 20 to hermetically seal it reduced the decrease in oxygen concentration caused by the operation of the light-emitting element 12.

[0035] In a sample having a light-reflecting member 14, the inside of the recess 11 was heated to 250°C in an oxygen atmosphere, and then the inside of the recess 11 was exposed to the atmosphere. After that, when the lid member 20 was placed and hermetically sealed, a decrease in oxygen concentration occurred due to the operation of the light-emitting element 12.

[0036] From the above results, the following can be considered. When the light-reflecting member 14 is exposed to the atmosphere, organic matter in the atmosphere adheres to the light-reflecting member 14. In particular, if the light-reflecting member 14 is porous, the surface area to which organic matter adheres increases. Therefore, a porous light-reflecting member 14 can have more organic matter adhered to it. When the light-emitting element 12 is hermetically sealed in the internal space 18 and the light-emitting element 12 is driven, the temperature of the light-reflecting member 14 rises. Due to the rise in temperature, the adhered organic matter volatilizes, and the volatilized organic matter is oxidized by the oxygen gas sealed in the internal space 18. It is thought that the oxidation of the adhered organic matter lowers the oxygen concentration in the internal space 18, and increases the water concentration and carbon dioxide concentration. Therefore, by opening the recess 11 and heating the inside of the recess 11 in an oxygen atmosphere, the organic matter attached to the light-reflecting member 14 can be burned off and removed. After the organic matter attached to the light-reflecting member 14 is removed by combustion, if the light-reflecting member 14 is exposed to the atmosphere, organic matter in the atmosphere will adhere to the light-reflecting member 14 again.

[0037] (Comparison Form 2) As comparative form 2, a light-emitting device was created that, like comparative form 1, does not have a through hole 16, a metal film 28, and a metal member 29. The light-emitting device of comparative form 2 has a light-reflecting member 14. In the light-emitting device of comparative form 2, the inside of the recess 11 is heated to 250°C in an oxygen atmosphere, and then the lid member 20 is placed to hermetically seal it. To prevent organic matter from adhering to the light-reflecting member 14 again after the organic matter adhering to the light-reflecting member 14 is removed by heating, the heating process (i.e., the process of burning and removing the organic matter) and the process of hermetically sealing with the lid member 20 are performed in the same device. For this reason, in comparative form 2, a bonding member 22 (specifically, gold-tin solder) is placed in advance on the upper surface 10A of the package 10 and heated to 250°C in an oxygen atmosphere. Subsequently, the oxygen gas inside the apparatus is discharged, and the apparatus is filled with a mixed gas atmosphere of oxygen and nitrogen for airtight sealing. The lid member 20 is then placed on the joining member 22, and the package 10 is heated to 300°C, causing the joining member 22 to melt and the lid member 20 to be joined to the package 10.

[0038] Here, if the bonding member 22 is placed on the upper surface 10A of the package 10 and heated to remove the adhering material, the bonding member 22 may deteriorate due to the heating. For example, if the bonding member 22 is gold-tin solder containing tin, the tin in the gold-tin may oxidize, making it difficult for the bonding member 22 to wet and spread onto the metal films 22A and 22B, which may result in poor airtightness.

[0039] (Manufacturing method of the first embodiment) A manufacturing method according to the first embodiment will now be described. The manufacturing method according to the first embodiment includes the steps of: preparing a package 10 having a recess 11 on its upper surface 10A and a through hole 16 in its inner surface 11C defining the recess 11; arranging a light-emitting element 12 on the inner surface 11C away from the through hole 16; arranging a light-reflecting member 14 on the inner surface 11C away from the light-emitting element 12 and the through hole 16; closing the opening 11D of the recess 11 by arranging a lid member 20 on the upper surface 10A via a joining member 22; removing any deposits adhering to the light-reflecting member 14 from the through hole 16 after the closing of the opening 11D; and hermetically sealing the light-emitting element 12 by blocking the through hole 16 after the removal step. The manufacturing method according to the first embodiment can solve the problems in comparative embodiment 1 and comparative embodiment 2. Figures 8A to 10B are cross-sectional views showing the manufacturing method according to the first embodiment. Figures 8A to 10B show some of the components in a simplified manner compared to Figures 1 to 4.

[0040] (Preparing package 10) As shown in Figure 8A, a package 10 is prepared having an upper surface 10A with a recess 11 and a lower surface 10B opposite to the upper surface 10A. The inner surface 11C of the recess 11 has a bottom surface 11A and a side surface 11B.

[0041] Next, a through-hole 16 is formed that penetrates from the inner surface 11C defining the recess 11 to the bottom surface 10B. For example, as shown in Figure 8B, a jig 30 having a lower jig 31 and an upper jig 32 is prepared, and the package 10 is placed between the lower jig 31 and the upper jig 32. The opening 30A of the upper jig 32 exposes a part of the bottom surface 10B of the package 10. By irradiating the bottom surface 10B with laser light through the opening 30A, a through-hole 16 is formed that extends from the bottom surface 10B to the inner surface 11C of the recess 11. Next, using the upper jig 32 as a mask, a metal film 28 is formed on the bottom surface 10B and the inner surface 16A of the through-hole 16. The metal film 28 can be formed, for example, using a sputtering method. It is preferable that the through-hole 16 has a shape in which the width of the inner surface widens from the bottom surface 11A toward the bottom surface 10B. This makes it easy to cover the inner surface 16A of the through-hole 16 with the metal film 28. As described above, a package 10 having a through hole 16 in the inner surface 11C defining the recess 11 can be prepared. Although only one package 10 is shown in Figures 8A and 8B, the prepared package 10 may be pre-assembled into individual pieces as shown, or it may be a composite substrate containing multiple regions that will become individual packages 10 after assembly. Furthermore, the package 10 may be prepared by purchasing, transferring, or otherwise obtaining a package 10 having a recess 11 on its upper surface 10A and a through hole 16 in the inner surface 11C defining the recess 11.

[0042] (Step of placing the light-emitting element 12) Next, as shown in Figure 9A, the light-emitting element 12 is mounted on the bottom surface 11A of the recess 11. At this time, the light-emitting element 12 is positioned away from the through hole 16. For example, the light-emitting element 12 is flip-chip mounted on the wiring 24A and wiring 24B shown in Figures 1 and 3 via conductive members 25A and 25B. Furthermore, a protective element 13 may be placed on the bottom surface 11A.

[0043] (Step of arranging the light-reflecting member 14) Next, as shown in Figure 9B, light-reflecting members 14 are placed on the bottom surface 11A and the side surface 11B. The light-reflecting member 14 has a light-reflecting material 14A, a support member 14B containing particles 14C, and a void 14D. In the step of placing the light-reflecting member 14, the light-reflecting member 14 is placed away from the through hole 16. The method of placing the light-reflecting member 14 is as follows: The powder constituting the particles 14C (e.g., silicon oxide) and the powder constituting the light-reflecting material 14A (e.g., boron nitride or aluminum oxide) are stirred and mixed. The stirred powder is mixed with an aqueous alkali metal hydroxide solution. The mixed mixture is placed from the bottom surface 11A to the side surface 11B. The mixture is heated and hardened to form the light-reflecting member 14. The heating temperature of the mixture is, for example, 150°C to 250°C. After that, alkali ions in the light-reflecting member 14 are removed by washing with water. The powder of particle 14C to be mixed is silicon dioxide as an example, the powder of light reflector 14A to be mixed is boron nitride as an example, and the alkali metal hydroxide is potassium hydroxide as an example.

[0044] (Step to close the opening of the recess 11) Next, as shown in Figure 9C, the lid member 20 is joined to the upper surface 10A of the package 10 using a joining member 22. The step of closing the opening 11D includes, for example, the step of heating the joining member 22 to a first temperature. The joining member 22 is, as an example, gold tin. In this case, the package 10 in which the gold tin is placed is heated to a first temperature (for example, 300°C to 350°C) at which the gold tin melts, thereby melting the gold tin and joining the lid member 20 to the upper surface 10A of the package 10. As a result, the opening 11D of the recess 11 of the package 10 is closed by the lid member 20.

[0045] (Process for removing attached substances) Next, as shown in Figure 10A, a metal member 29A is placed on the metal film 28 surrounding the through hole 16. The metal member 29A is, for example, gold-tin. Here, molten gold-tin is placed on the metal film 28. The placed metal member 29A solidifies and remains on the metal film 28. Then, the internal space 18 is depressurized through the through hole 16. Subsequently, the internal space 18 is made an oxygen atmosphere through the through hole 16, and the package 10 is heated to a second temperature under the oxygen atmosphere. This oxidizes the organic matter adhering to the light-reflecting member 14. After that, the internal space 18 is depressurized through the through hole 16 to remove water, carbon dioxide, etc., generated in the internal space 18 by the oxidation of the organic matter. The removal step includes heating at a second temperature lower than the first temperature. The second temperature for heating the package 10 is, for example, 150°C to 250°C. Note that if the adhering matter on the light-reflecting member 14 can be removed at room temperature, heating the package 10 is not necessary.

[0046] (The process of hermetically sealing the area) Next, as shown in Figure 10B, the internal space 18 is made into an airtight sealing gas atmosphere through the through-hole 16. The airtight sealing gas contains, for example, oxygen, and is a mixture of oxygen and nitrogen gas. By heating the package 10 in the airtight sealing gas atmosphere, the metal member 29A is melted. The molten metal member 29A flows into the through-hole 16 and seals the through-hole 16 as metal member 29. If the metal member 29A is gold-tin, the temperature of the package 10 is set to, for example, 300°C to 350°C.

[0047] As shown in Figure 10B, it is preferable that the package 10 has a metal film 28 that extends from the inner surface 16A of the through hole 16 to the outer surface of the package 10. By having a metal film 28 that is continuous from the lower surface 10B of the package 10 to the inner surface of the through hole 16, it is possible to easily move the metal member 29A placed on the metal film 28 to the inner surface of the through hole 16 by melting. This makes it possible to efficiently seal the through hole 16. It is preferable that the metal film 28 covers the entire inner surface of the through hole 16. The metal film 28 may or may not be positioned over the inner surface of the recess 11 of the package 10. It is preferable that the metal film 28 is spaced apart from the wiring 24A and 24B and the external connection terminals 26A and 26B of the package 10.

[0048] The shape of the through-hole 16 (i.e., the area defined by the inner surface 16A of the through-hole 16) can be columnar, frustoconical, or a modified version thereof. The opening shape of the through-hole 16 can be a polygon such as a triangle or quadrilateral, a circle, or an ellipse. Preferably, the through-hole 16 has a shape that widens toward the outer surface of the package 10. In other words, preferably, the inner surface defining the through-hole 16 of the package 10 has a shape that slopes so as to widen from the bottom surface 11A of the recess 11 toward the bottom surface of the package 10. This makes it easy to deposit the metal film 28 onto the inner surface 16A in the process of preparing the package shown in Figure 8B. In addition, it is possible to reduce the adhesion of dust and other particles to the internal space 18 before closing the through-hole 16 with the metal member 29.

[0049] The through-hole 16 is, for example, cone-shaped. The size of the through-hole 16 on the bottom surface 11A side of the recess 11 (i.e., the size of the opening of the through-hole 16) can be, for example, 30 μm to 130 μm. This allows the through-hole 16 to be closed by the metal member 29. The size of the through-hole 16 on the bottom surface side of the package 10 can be, for example, 10 μm to 100 μm. This allows for efficient gas movement between the internal space 18 and the outside through the through-hole 16.

[0050] Furthermore, the through hole 16 does not have to be located on the bottom surface 11A of the recess 11; it may be located at any location on the inner surface 11C of the recess 11. Also, the light-emitting element 12 does not have to be located on the bottom surface 11A of the recess 11; it may be located on the inner surface 11C of the recess 11. In addition, the light-reflecting member 14 does not have to be located on the bottom surface 11A of the recess 11; it may be located on the inner surface 11C of the recess 11.

[0051] Figures 11A to 11C are enlarged plan views showing the manufacturing method of the light-emitting device in the first embodiment. Figures 11A and 11B are plan views of the area near the through-hole 16 on the lower surface 10B of the package 10 in Figure 10A, and correspond to enlarged views of the area where the metal film 28 in Figure 2 is placed. Figure 11C is a plan view of the area near the through-hole 16 on the lower surface 10B of the package 10 in Figure 10B.

[0052] In Figure 11A, two metal members 29A are arranged so as to sandwich the through hole 16. In Figure 11B, four metal members 29A are arranged so as to surround the through hole 16. As shown in Figure 11B, by melting the metal members 29A, they move due to their wettability and block the through hole 16. If the metal members 29A are solder containing tin, such as gold-tin solder, by setting the heating temperature of the package 10 to, for example, 300°C to 350°C, the metal members 29A melt and spread onto the metal film 28, blocking the through hole 16 as metal members 29. Thus, a light-emitting device is manufactured.

[0053] One or more metal members 29A can be placed in a single through hole 16. Multiple metal members 29A may also be placed. This allows the through hole 16 to be efficiently sealed. Furthermore, as shown in Figures 11A and 11B, multiple metal members 29A may be placed on either side or surrounding the through hole 16. This allows the through hole 16 to be efficiently sealed, as shown in Figure 11C.

[0054] According to the manufacturing method of the first embodiment described above, in a method for manufacturing a light-emitting device in which the inside of the package 10 is hermetically sealed, it is possible to reduce the decrease in the reliability of the light-emitting device due to deposits adhering to the light-reflecting member 14 after hermetically sealing. In other words, by removing the organic matter adhering to the light-reflecting member 14 and then sealing the through-hole 16, the decrease in oxygen concentration in the hermetically sealed gas can be reduced, as in Sample B of Comparative Embodiment 1. Therefore, the reliability of the light-emitting device can be improved.

[0055] Furthermore, by removing organic matter adhering to the light-reflecting member 14 after closing the opening 11D of the recess 11 using the lid member 20, the deterioration of the bonding member 22 due to the removal of organic matter can be reduced. Therefore, the deterioration of the hermetic seal as in comparative form 2 can be reduced. Thus, the reliability of the light-emitting device can be improved.

[0056] From the viewpoint of preventing organic matter from reattaching to the light-reflecting member 14, it is preferable not to expose the light-reflecting member 14 to the atmosphere between removing the organic matter adhering to the light-reflecting member 14 in Figure 10A and sealing the through-hole 16 in Figure 10B.

[0057] The light-reflecting member 14 may contain organic materials or may be composed substantially of inorganic materials. When the light-emitting element 12 emits short-wavelength light such as ultraviolet light, it is preferable that the light-reflecting member 14 be composed of inorganic materials. In the process of arranging the light-reflecting member 14, by removing any adhering organic matter and then sealing the through-hole 16, the oxygen concentration in the internal space 18, which is airtightly sealed with an oxygen-containing gas, can be kept substantially constant. When the light-reflecting member 14 is porous, organic matter tends to adhere to it, so when the light-reflecting member 14 is porous, the manufacturing method according to the first embodiment can be suitably used.

[0058] In the step of arranging the light-reflecting member 14 in Figure 9B, a mixture of silicon oxide, boron nitride or aluminum oxide, and an aqueous hydroxide solution of an alkali metal is placed on the inner surface 11C of the recess 11, and the package 10 is heated. Organic matter tends to adhere to the light-reflecting member 14 made of such materials. Therefore, in the manufacturing method of the light-emitting device according to this embodiment, it is preferable to seal the through hole 16 after removing the organic matter.

[0059] In the step of closing the opening 11D in Figure 9C, the joining member 22 may be a metal member such as solder, or a resin member such as silicone. From the viewpoint of hermetically sealing the light-emitting element 12, it is preferable to use a metal member. For example, gold-tin solder can be suitably used as the metal member. However, if the joining member 22 contains tin, as in comparative form 2, if organic matter is removed by heating before joining the lid member 20 to the upper surface 10A, the deterioration of the joining member 22 (specifically oxidation of tin) during the organic matter removal process may cause a joining failure and prevent hermetically sealing. Therefore, if the joining member 22 contains tin, it is preferable to perform heating for organic matter removal after closing the opening 11D of the recess 11. Examples of tin-containing joining member 22 include gold-tin solder, tin-silver solder, or tin-silver-copper solder.

[0060] In Figure 10A, the gas used to fill the internal space 18 when removing organic matter does not necessarily have to contain oxygen; it is sufficient that it can remove the organic matter. Preferably, the gas used to fill the internal space 18 contains oxygen. This oxidizes the organic matter, and the gas containing the oxidized organic matter can be removed from the through-hole 16. The oxygen-containing gas is, for example, a gas with 100% oxygen by volume, or a mixed gas of oxygen and an inert gas. The oxygen concentration in the mixed gas is preferably 15% by volume or more, and more preferably 20% by volume or more.

[0061] In the hermetically sealing process shown in Figure 10B, the gas used to hermetically seal the light-emitting element 12 preferably contains oxygen. If organic matter adheres to the light-reflecting member 14 and the element is hermetically sealed with an oxygen-containing gas, the organic matter adhering to the light-reflecting member 14 will oxidize, reducing the oxygen concentration in the internal space 18. This may reduce the reliability of the light-emitting device. Therefore, it is preferable to remove the organic matter and then seal the through-hole 16 in an oxygen-containing gas atmosphere. The gas used to hermetically seal the light-emitting element 12 is, for example, a mixture of oxygen and an inert gas. The concentration of oxygen gas in the sealed gas is, for example, 15% by volume or more and 25% by volume or less. The gas used to hermetically seal the light-emitting element 12 and the gas used to remove organic matter may be gases with the same components.

[0062] As described above, in the removal process shown in Figure 10A, the package 10 is heated at a second temperature lower than the first temperature at which the joining member 22 is heated in the process of closing the opening 11D of the recess 11 shown in Figure 9C. As a result, the joining member 22 does not remelt in the removal process, and the opening 11D of the recess 11 can be sealed with the lid member 20 and the joining member 22. Thus, when removing organic matter after closing the opening 11D of the recess 11, it is preferable that the second temperature in Figure 10A is lower than the first temperature in Figure 9C. In this case, it is preferable that the temperature difference between the first temperature and the second temperature be 20°C or more.

[0063] In the manufacturing method of the first embodiment, organic matter was described as an example of the deposits adhering to the light-reflecting member 14, but the deposits adhering to the light-reflecting member 14 may be other than organic matter. In such cases as well, after closing the opening 11D of the recess 11 with the lid member 20, the deposits adhering to the light-reflecting member 14 are removed through the through hole 16, and then the through hole 16 is sealed. This reduces the deterioration of the characteristics of the light-emitting device and the failure of hermetic sealing caused by deposits adhering to the light-reflecting member 14.

[0064] 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.

[0065] A method for manufacturing a light-emitting device according to the embodiments of this disclosure includes, for example, the following embodiments. (Item 1) A step of preparing a package having an upper surface with a recess and a lower surface opposite to the upper surface, and having a through hole in the inner surface defining the recess that penetrates from the inner surface to the lower surface, The process of arranging a light-emitting element on the inner surface away from the through hole, The process of arranging a light-reflecting member on the inner surface, away from the light-emitting element and the through-hole, The process of closing the opening of the recess by placing a lid member on the upper surface via a connecting member, After the step of closing the opening, the step of removing any deposits adhering to the light-reflecting member from the through-hole, After the removal step, the process involves sealing the light-emitting element by blocking the through-hole, A method for manufacturing a light-emitting device, including the method described above. (Section 2) The method for manufacturing a light-emitting device according to claim 1, wherein the step of arranging the light-reflecting member includes arranging a mixture of silicon oxide, boron nitride or aluminum oxide, and an aqueous hydroxide solution of an alkali metal on the inner surface of the recess. (Section 3) The method for manufacturing a light-emitting device according to item 1 or 2, wherein in the step of hermetically sealing, the light-emitting element is hermetically sealed with a gas containing oxygen. (Section 4) The method for manufacturing a light-emitting device according to any one of claims 1 to 3, wherein the joining member contains tin. (Section 5) The step of closing the opening includes the step of heating the joining member to a first temperature, The method for manufacturing a light-emitting device according to any one of claims 1 to 4, wherein the removal step includes a step of heating the package at a second temperature lower than the first temperature. (Section 6) The method for manufacturing a light-emitting device according to any one of claims 1 to 5, wherein the light-emitting element emits ultraviolet light. (Section 7) The method for manufacturing a light-emitting device according to any one of claims 1 to 6, wherein the through-hole extends toward the outer surface of the package. (Section 8) The package has a metal film that is arranged from the inner surface defining the through hole to the outer surface of the package, A method for manufacturing a light-emitting device according to item 7, wherein in the step of sealing the through-hole, a metal member is placed on the metal film on the outer surface, and the package is heated to melt the metal member and seal the through-hole. (Section 9) The inner surface defining the recess has a side surface and a bottom surface in which the through hole is located. A method for manufacturing a light-emitting device according to any one of items 1 to 8, wherein in the step of arranging the light-emitting element, the light-emitting element is arranged on the bottom surface. (Section 10) The method for manufacturing a light-emitting device according to item 9, wherein in the step of arranging the light-reflecting member, the light-reflecting member is arranged on the bottom surface. (Section 11) A method for manufacturing a light-emitting device according to item 9 or 10, wherein the package has wiring on its bottom surface and the through-hole is away from the wiring. (Section 12) The method for manufacturing a light-emitting device according to any one of claims 9 to 11, wherein the through holes are multiple. [Explanation of Symbols]

[0066] 10 packages 10A top 10B Bottom 11 recess 11A Bottom 11B Side 11C Inner surface 12 Light-emitting elements 13. Protective elements 14 Light-reflecting member 14A Light-reflective material 14B Support Member 14C particles 14D void 16 Through holes 16A Inner surface 18 Interior space 20 Lid member 20A Translucent material 22A, 22B, 28 Metal film 24A, 24B wiring 25A, 25B Conductive material 26A, 26B External connection terminals 29 Metal components

Claims

1. A step of preparing a package having an upper surface with a recess and a lower surface opposite to the upper surface, and having a through hole in the inner surface defining the recess that penetrates from the inner surface to the lower surface, The process of arranging a light-emitting element on the inner surface away from the through hole, The process of arranging a light-reflecting member on the inner surface, away from the light-emitting element and the through-hole, The process of closing the opening of the recess by placing a lid member on the upper surface via a connecting member, After the step of closing the opening, the step of removing any deposits adhering to the light-reflecting member from the through-hole, After the removal step, the process involves sealing the light-emitting element by blocking the through-hole, A method for manufacturing a light-emitting device, including the method described above.

2. The method for manufacturing a light-emitting device according to claim 1, wherein the step of arranging the light-reflecting member includes arranging a mixture of silicon oxide, boron nitride or aluminum oxide, and an aqueous hydroxide solution of an alkali metal on the inner surface of the recess.

3. The method for manufacturing a light-emitting device according to claim 1 or 2, wherein in the step of hermetically sealing, the light-emitting element is hermetically sealed with a gas containing oxygen.

4. The method for manufacturing a light-emitting device according to claim 1 or 2, wherein the joining member contains tin.

5. The step of closing the opening includes the step of heating the joining member to a first temperature, The method for manufacturing a light-emitting device according to claim 1 or 2, wherein the removal step includes a step of heating the package at a second temperature lower than the first temperature.

6. The method for manufacturing a light-emitting device according to claim 1 or 2, wherein the light-emitting element emits ultraviolet light.

7. The method for manufacturing a light-emitting device according to claim 1 or 2, wherein the through-hole widens toward the outer surface of the package.

8. The package has a metal film that is arranged from the inner surface defining the through hole to the outer surface of the package, The method for manufacturing a light-emitting device according to claim 7, wherein in the step of sealing the through-hole, a metal member is placed on the metal film on the outer surface, and the package is heated to melt the metal member and seal the through-hole.

9. The inner surface defining the recess has a side surface and a bottom surface in which the through hole is located. A method for manufacturing a light-emitting device according to claim 1 or 2, wherein in the step of arranging the light-emitting element, the light-emitting element is arranged on the bottom surface.

10. The method for manufacturing a light-emitting device according to claim 9, wherein in the step of arranging the light-reflecting member, the light-reflecting member is arranged on the bottom surface.

11. The method for manufacturing a light-emitting device according to claim 9, wherein the package has wiring on its bottom surface, and the through-hole is separated from the wiring.

12. The method for manufacturing a light-emitting device according to claim 9, wherein there are multiple through holes.

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