Manufacturing method for light-emitting device

Abstract

To provide a manufacturing method for a light-emitting device that can improve yield during manufacturing while achieving wide-angle light distribution.SOLUTION: A manufacturing method for a light-emitting device includes: a preparing step of preparing a substrate having an upper surface on which a plurality of light-emitting elements are disposed, each of the plurality of light-emitting elements including a light-emitting layer; a phosphor layer forming step of forming a phosphor layer by pouring a first precursor made of a resin in which phosphor particles are dispersed onto the upper surface of the substrate and heat-curing the poured first precursor, the phosphor layer encompassing the plurality of light-emitting elements; a trench forming step of forming a trench on an upper surface of the phosphor layer to separate each of the light-emitting elements in a top view from a direction perpendicular to the upper surface; a sealing layer forming step of forming a sealing layer by pouring a second precursor made of a translucent resin onto the upper surface of the phosphor layer and heat-curing the poured second precursor; a transmissive-reflective layer forming step of forming a transmissive-reflective layer on the sealing layer, the transmissive-reflective layer partially reflecting and partially transmitting each of light emitted from the light-emitting layer and the phosphor layer on the sealing layer; and an individualizing step of individualizing the light-emitting device by cutting from an upper surface of the transmissive-reflective layer to the substrate along the trench in a depth direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a light emitting device including a light emitting element. [Background technology]

[0002] Light-emitting devices have been disclosed in which a phosphor layer including a light-emitting element is covered with a transparent resin layer. For example, Patent Document 1 discloses a light-emitting device having a light-emitting element arranged on a substrate, a color conversion package including color conversion particles formed on the substrate so as to include the light-emitting element, and a transparent package made of resin that covers the entire color conversion package. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-162976 Summary of the Invention [Problem to be solved by the invention]

[0004] When manufacturing the light-emitting device disclosed in Patent Document 1, for example, after forming the color-converting package, when a dicer is used to separate the color-converting package into individual light-emitting devices, there is a risk that the dicer blade may reach the substrate.

[0005] If the dicer blade reaches the substrate when dividing the color-converting package as described above, the substrate is likely to bend, which could cause the color-converting package to peel off from the substrate or break the wiring formed on the substrate, which would reduce the yield of the light-emitting device manufacturing process.

[0006] Furthermore, in the light emitting device disclosed in Patent Document 1, the emitted light has a Lambertian light distribution. Therefore, in an environment where light with a wider light distribution angle than the Lambertian light distribution is required, such as a light source for an auxiliary lamp in a vehicle, the light emitting device disclosed in Patent Document 1 may not be usable as a light source.

[0007] The present invention has been made in view of the above points, and provides a method for manufacturing a light emitting device that can improve the yield during manufacturing while achieving a wide-angle light distribution. [Means for solving the problem]

[0008] a phosphor layer forming step of forming grooves on the upper surface of the phosphor layer so as to separate each of the plurality of light-emitting elements in a top view perpendicular to the upper surface; a sealing layer forming step of forming a sealing layer on the upper surface of the phosphor layer by pouring a second precursor made of a translucent resin on the upper surface of the phosphor layer and heat-curing the poured second precursor; a transmission-reflection layer forming step of forming a transmission-reflection layer on the sealing layer that reflects and transmits a portion of the light emitted from the light-emitting layer and the fluorescence emitted from the phosphor layer; and a singulation step of cutting from the upper surface of the transmission-reflection layer to the substrate in a depth direction along the grooves to individualize the light-emitting devices. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a top view of the light emitting device according to the first embodiment. [Figure 2] FIG. 2 is a bottom view of the light emitting device according to the first embodiment. [Figure 3] 1 is a cross-sectional view of a light emitting device according to a first embodiment. [Figure 4] 1 is a cross-sectional view of a light emitting device according to a first embodiment. [Figure 5] 10 is a table showing the results of verification of the light emitting device according to Example 1. [Figure 6] 3A to 3C are cross-sectional views showing manufacturing steps of a first manufacturing method for the light emitting device according to Example 1. [Figure 7] 3A to 3C are cross-sectional views showing manufacturing steps of a first manufacturing method for the light emitting device according to Example 1. [Figure 8] 3A to 3C are cross-sectional views showing manufacturing steps of a first manufacturing method for the light emitting device according to Example 1. [Figure 9] 3A to 3C are cross-sectional views showing manufacturing steps of a first manufacturing method for the light emitting device according to Example 1. [Figure 10] 5A to 5C are cross-sectional views showing manufacturing steps of a second manufacturing method for the light emitting device according to Example 1. [Figure 11] 5A to 5C are cross-sectional views showing manufacturing steps of a second manufacturing method for the light emitting device according to Example 1. [Figure 12] 5A to 5C are cross-sectional views showing manufacturing steps of a second manufacturing method for the light emitting device according to Example 1. [Figure 13] 5A to 5C are cross-sectional views showing manufacturing steps of a second manufacturing method for the light emitting device according to Example 1. [Figure 14] 5A to 5C are cross-sectional views showing manufacturing steps of a second manufacturing method for the light emitting device according to Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same components are designated by the same reference numerals, and the description of the same components will be omitted. [Example]

[0011] [Outline of Light-Emitting Device 100] The configuration of a light emitting device 100 according to Example 1 will be described with reference to Figs. 1 to 4. Fig. 1 is a top view of the light emitting device 100 according to Example 1. Fig. 2 is a bottom view of the light emitting device 100 according to Example 1. Fig. 3 is a cross-sectional view of the light emitting device 100 taken along line 3-3 in Fig. 1. Fig. 4 is a cross-sectional view of the light emitting device 100 taken along line 4-4 in Fig. 1.

[0012] In Figures 1 and 2, the center line (two-partition line) in the width direction (left-right direction in the figure) of the light-emitting device 100 is shown by a dotted line as center line CL1, and the center line (two-partition line) in the depth direction (up-down direction in the figure) of the light-emitting device 100 is shown by a dotted line as center line CL2.

[0013] 3, the left-right direction in the drawing is the width direction of the light emitting device 100, and the up-down direction in the drawing is the height direction of the light emitting device 100. In addition, in FIG. 4, the left-right direction in the drawing is the depth direction of the light emitting device 100, and the up-down direction in the drawing is the height direction of the light emitting device 100.

[0014] As shown in Figures 3 and 4, the light-emitting device 100 is composed of a substrate 11, a light-emitting element 13 provided on the substrate 11, a phosphor layer 15 formed on the substrate 11 to cover the light-emitting element 13, a sealing layer 17 formed to cover the phosphor layer 15, and a transmissive-reflective layer 19 formed over the upper surface of the sealing layer 17.

[0015] [Substrate 11] First, the substrate 11 will be described. The substrate 11 is a flat, insulating glass epoxy substrate (FR-4) having a rectangular upper surface. A ceramic substrate made of alumina (Al2O3) or aluminum nitride (AlN) may also be used for the substrate 11. An anode pad 21 and a cathode pad 22 are formed on the upper surface of the substrate 11. An anode electrode 23 and a cathode electrode 24 are formed on the lower surface of the substrate 11.

[0016] The anode pad 21 and the cathode pad 22 are a pair of element mounting pads each having a rectangular upper surface and formed on the upper surface of the substrate 11 at a distance from each other with the center line CL1 therebetween.

[0017] The anode pad 21 has two extension portions 21A that extend from each of the short sides along the center line CL1 and reach the outer edge of the substrate 11. The anode pad 21 also has two extension portions 21B that extend from one of the long sides along the center line CL2 on either side of the center line CL2 and reach the outer edge of the substrate 11.

[0018] Similar to the anode pad 21, the cathode pad 22 has two extending portions 22A that extend from each of the short sides along the center line CL1 and reach the outer edge of the substrate 11. The cathode pad 22 also has two extending portions 22B that extend from one of the long sides along the center line CL2 on either side of the center line CL2 and reach the outer edge of the substrate 11.

[0019] The anode electrode 23 and the cathode electrode 24 are a pair of electrodes each having a rectangular upper surface shape, formed at a distance from each other on either side of the center line CL2 on the lower surface of the substrate 11. In the light-emitting device 100, in a top view of the substrate 11, the longitudinal directions of the anode pad 21 and the cathode pad 22 and the longitudinal directions of the anode electrode 23 and the cathode electrode 24 are perpendicular to each other.

[0020] Each of the anode pad 21, the cathode pad 22, the anode electrode 23, and the cathode electrode 24 is made of copper (Cu), and the surface thereof is plated with nickel (Ni) and gold (Au) in this order. Note that the plating process may be performed with silver (Ag) instead of Au.

[0021] In the light emitting device 100, the anode pad 21 and the anode electrode 23 are electrically connected through a conductive via 25 made of Cu. Similarly, the cathode pad 22 and the cathode electrode 24 are electrically connected through the conductive via 25.

[0022] [Light-emitting element 13] Next, a description will be given of the light emitting element 13. As described above, the light emitting element 13 is disposed on the upper surface of the substrate 11, and is a light emitting diode (LED) having a rectangular upper surface shape.

[0023] As shown in FIGS. 3 and 4, the light emitting element 13 includes a semiconductor structure layer 27 having a light emitting layer made of a semiconductor, and a light-transmitting substrate 28 disposed on the upper surface of the semiconductor structure layer 27.

[0024] The semiconductor structure layer 27 is a semiconductor laminate including an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer (none of which are shown), each of which is made primarily of gallium nitride (GaN). When the light-emitting element 13 is driven, the light-emitting layer of the semiconductor structure layer 27 emits blue light having a peak wavelength of 450 nm.

[0025] The light-transmitting substrate 28 is a flat substrate having a rectangular upper surface. The light-transmitting substrate 28 is made of a material, such as sapphire (Al2O3) or GaN, that is transmissive to the blue light emitted from the light-emitting layer of the semiconductor structure layer 27 and the fluorescent light emitted from the phosphor layer 15 (described later). The light-transmitting substrate 28 also serves as a growth substrate for the semiconductor structure layer 27.

[0026] The light emitting element 13 includes a p-electrode 31 and an n-electrode 32, each of which has a rectangular upper surface shape and is formed on the lower surface of the semiconductor structure layer 27. The p-electrode 31 is an electrode electrically connected to the p-type semiconductor layer of the semiconductor structure layer 27. The surface of the p-electrode 31 is plated with gold (Au).

[0027] The n-electrode 32 is an electrode electrically connected to the n-type semiconductor layer via a through electrode (not shown) that vertically penetrates the light-emitting layer and p-type semiconductor layer of the semiconductor structure layer 27 and has a side surface covered with an insulator. In other words, the n-electrode 32 is electrically connected only to the n-type semiconductor layer and is insulated from the light-emitting layer and p-type semiconductor layer. The surface of the n-electrode 32 is plated with Au.

[0028] The p-electrode 31 and the n-electrode 32 are respectively bonded to the anode pad 21 and the cathode pad 22 via epoxy resin solder 33. That is, in the light emitting device 100, the light emitting element 13 is flip-chip mounted on the substrate 11.

[0029] The epoxy resin solder 33 contains fine solder metal particles such as tin-silver-copper (Sn-Ag-Cu) in an epoxy resin flux, and after bonding, the epoxy resin covers the periphery of the solder joint, increasing the bonding strength. Furthermore, since the periphery of the solder joint is made of epoxy resin, this is preferable because it improves adhesion to the phosphor layer 15. Alternatively, gold-tin (Au-Sn) solder using a volatile flux may be used as the epoxy resin solder 33.

[0030] [Phosphor layer 15] Next, the phosphor layer 15 will be described. The phosphor layer 15 has a rectangular upper surface shape and is provided on the substrate 11 to encompass the light emitting element 13. The phosphor layer 15 has a frame-shaped portion 15F that protrudes laterally from the lower end of the side surface along the upper surface of the substrate 11 and is continuously formed around the periphery of the phosphor layer 15 in a top view. The frame-shaped portion 15F extends from the lower end of the side surface of the phosphor layer 15 to the outer edge of the substrate 11.

[0031] Phosphor layer 15 contains a phosphor that emits fluorescence when excited by blue light as excitation light emitted from light emitting element 13. When excited by blue light, the phosphor layer emits green fluorescence having a green peak wavelength in the wavelength range of 500 to 580 nm and red fluorescence having a red peak wavelength in the wavelength range of 620 to 640 nm.

[0032] The phosphor layer 15 is formed by dispersing KSF (K2SiF6:Mn) phosphor particles that emit red fluorescence and β-sialon phosphor particles that emit green fluorescence in a light-transmitting resin such as silicone resin.

[0033] When blue light emitted from the light-emitting element 13 enters the phosphor layer 15, part of the light passes through the phosphor layer 15 as is, and part of the light excites the phosphor particles, causing the excited phosphor particles to emit fluorescence.

[0034] Therefore, excitation light (blue light) that has passed through phosphor layer 15 without contributing to the generation of fluorescence, and fluorescence (green light and red light) emitted from the phosphor particles are emitted from the upper surface of phosphor layer 15. As a result, white light that is a mixture of blue light, red fluorescence, and green fluorescence is extracted from the upper surface of phosphor layer 15.

[0035] [Sealing layer 17] Next, the sealing layer 17 will be described. The sealing layer 17 is a light-transmitting layer that covers the upper surface of the phosphor layer 15, extends from the upper end of the side surface of the phosphor layer 15 to cover the side surface, and terminates at the upper surface of the frame-shaped portion 15F. The sealing layer 17 is made of, for example, a silicone resin that transmits white light (specifically, white band light).

[0036] The sealing layer 17 functions as a protective layer that protects the KSF phosphor, which is susceptible to deterioration by moisture, from the outside air by covering most of the phosphor layer 15. The sealing layer 17 also functions as a light-guiding layer that guides the white light emitted from the phosphor layer 15.

[0037] [Transmissive reflective layer 19] Next, we will explain the transflective layer 19. As described above, the transflective layer 19 is formed over the upper surface of the sealing layer 17, and is a layer that reflects part of the white light that is guided through the sealing layer 17 and emitted, while transmitting part of the white light.

[0038] In the light emitting device 100 of this embodiment, the transflective layer 19 is a dielectric multilayer film whose layer thickness is adjusted so that the reflectance for white light is a predetermined value. A dielectric multilayer film generates transmitted light and reflected light without attenuating the incident light, and is therefore suitable for controlling light distribution characteristics (directional characteristics). In the light emitting device 100, the transflective layer 19 is formed by alternately stacking 10 to 40 layers (5 to 20 pairs) of silicon oxide (SiO2) and alumina (Al2O3), for example.

[0039] The material of the transflective layer 19 may be a combination of titanium oxide (TiO2), niobium oxide (NbO), magnesium oxide (MgO), tantalum oxide (Ta2O5), hafnium oxide (HfO), and the like.

[0040] In the light emitting device 100 of this embodiment, the reflectance of the transflective layer 19 for white light is set to 60%. As a result, the light emitted from the light emitting device 100 has a so-called batwing light distribution, in which the light intensity directly above the light emitting device 100 is reduced while the light intensity to the sides is increased. In other words, the light emitted from the light emitting device 100 has a wider angle light distribution (half angle 140° to 180°) than the Lambertian light distribution (half angle 120°) in which the light intensity decreases from directly above the light emitting device to the sides.

[0041] The light emitting device 100 having such a batwing light distribution can be used in environments where light with a highly uniform brightness distribution over a wide range is required, such as the light source for auxiliary lights in vehicles or the light source for direct backlights in LCD-TVs.

[0042] As described above, phosphor layer 15 of light emitting device 100 of this embodiment has frame-shaped portion 15F continuously formed on the periphery of phosphor layer 15. For example, when phosphor layer 15 is divided into individual light emitting devices using a dicer during the manufacture of light emitting device 100, phosphor layer 15 can be processed so as to leave frame-shaped portion 15F, thereby improving the yield during manufacturing (details will be described later).

[0043] [verification] 3 to 5, the details and results of the verification performed on the light emitting device 100 of this example will be described. Fig. 5 is a table showing the light output ratio, luminance distribution, and luminance ratio (minimum luminance / maximum luminance) calculated by measuring the light output and luminance of each of six samples A to F based on the configuration of the light emitting device 100.

[0044] 5, each of samples B to F is different from sample A in either the height HP of phosphor layer 15 from the upper surface of substrate 11, the thickness HC of sealing layer 17 from the upper surface of phosphor layer 15 (see FIGS. 3 and 4), or the reflectance of transflective layer 19 for white light. The thickness of frame portion 15F from the upper surface of substrate 11 is defined as thickness HR.

[0045] In this verification, a measurement module was used in which 1mm square samples A to F were placed in the center of a 9mm square white case with an opening at the top. In addition, in this verification, the white cases with one sample placed in them were arranged in a 3x3 pattern with no gaps between them, and the light emitted from the area of ​​the white case 1 located in the center was used to measure the light output and brightness of each sample.

[0046] 5 shows the luminance distribution inside the case when the white cases in which samples A to F are placed are viewed from above, with darker areas indicating higher luminance. For example, in sample A, it can be seen that the luminance is highest around light-emitting device 100.

[0047] Furthermore, the closer the "brightness ratio" value in the table in Figure 5 is to 1, the more uniform the brightness of the light inside the white case. In other words, the higher the brightness ratio, the more evenly the light reaches inside the white case.

[0048] [Comparison of Samples A, B, and C] Samples A, B, and C differ only in the height HP of the phosphor layer 15 (0.4 mm, 0.6 mm, and 0.8 mm, respectively), but have the same thickness HC (0.1 mm) of the sealing layer 17 and the same reflectance (60%) of the transflective layer 19.

[0049] As shown in Fig. 5, when sample A is taken as 100%, the light output ratio is improved to 109.5% for sample B and 108.4% for sample C. The luminance ratio is also improved from 0.748 for sample A to 0.774 for sample B and 0.772 for sample C. In other words, sample B and sample C are superior to sample A in both light output ratio and luminance ratio.

[0050] [Comparison of Samples A, D, and E] Samples A, D, and E differ only in the thickness HC of the sealing layer 17 (0.1 mm, 0.3 mm, and 0.5 mm, respectively), but have the same height HP (0.4 mm) of the phosphor layer 15 and the same reflectivity (60%) of the transflective layer 19.

[0051] As shown in Fig. 5, the light output ratio is improved to 101.7% for Sample D and 102.3% for Sample E, with Sample A being taken as 100%. However, the brightness ratio is reduced to 0.723 for Sample D and 0.692 for Sample E, compared to 0.748 for Sample A. In other words, while Samples D and E are superior to Sample A in terms of light output ratio, Samples D and E are inferior to Sample A in terms of brightness ratio.

[0052] [Comparison of Samples A and F] Samples A and F differ only in the reflectance of the transflective layer 19 (60% and 90%, respectively), and have the same height HP (0.4 mm) of the phosphor layer 15 and the same thickness HC (0.1 mm) of the sealing layer 17.

[0053] As shown in Fig. 5, the light output ratio of sample F is 91.5%, which is lower than that of sample A, which is 100%. Also, the luminance ratio of sample F is 0.548, which is lower than that of sample A, which is 0.748. In other words, sample F is inferior to sample A in both light output ratio and luminance ratio.

[0054] [Verification Summary] From the comparison results of Samples A, B, and C, it is preferable that the height HP of the phosphor layer 15 from the upper surface of the substrate 11 be 0.6 mm to 0.8 mm in a 1 mm square light emitting device 100. In other words, it is preferable that the height HP of the phosphor layer 15 be 60% to 80% of the length of one side of the transflective layer 19 when the light emitting device 100 is viewed from above.

[0055] Furthermore, from the comparison results of Samples A, D, and E, in a 1 mm square light emitting device 100, it is preferable to set the thickness HC of the sealing layer 17 from the upper surface of the phosphor layer 15 to 0.1 mm, from the viewpoint of achieving a wide-angle light distribution by the light emitting device 100. In other words, it is preferable to set the height HP of the phosphor layer 15 to 10% of the length of one side of the transflective layer 19 when the light emitting device 100 is viewed from above.

[0056] Furthermore, from the comparison results of Samples A and F, it is preferable that the reflectance of the transflective layer 19 for white light be 60% in a 1 mm square light emitting device 100. Here, if the reflectance of the transflective layer 19 is below 50%, the central luminance of the white case increases and the luminance ratio decreases. Similarly, if the reflectance of the transflective layer 19 exceeds 70%, the central luminance of the white case decreases and the luminance ratio decreases. In other words, the preferred reflectance of the transflective layer 19 is 60±10%, and more preferably 60±5%.

[0057] In this way, according to the light emitting device 100 of this embodiment, it is possible to emit light having a wide-angle light distribution from the light emitting device 100.

[0058] In this embodiment, the light emitted from the light-emitting device 100 has been described as having a batwing light distribution, but it is sufficient that the light emitted from the light-emitting device 100 has a wide-angle light distribution, and it does not necessarily have to have a batwing light distribution.

[0059] For example, the reflectance of the transmissive reflective layer 19 of the light emitting device 100 for white light may be set to be lower than 60%. This allows the light output from directly above the light emitting device 100 to increase more than the batwing light distribution and gradually weaken toward the sides, thereby achieving an overall umbrella-shaped light distribution, or so-called umbrella light distribution.

[0060] [Modification of Light Emitting Device 100] Next, a description will be given of a modified example of Example 1. In this modified example, the configuration of the transflective layer 19 is different from that of Example 1, but the other configurations, such as the formation of the phosphor layer 15 and the sealing layer 17, are the same as those of Example 1.

[0061] In this modification, the transflective layer 19 is made of yttrium phosphate (YPO4) particles with a particle size of 1 to 5 nm dispersed in a silicone resin. YPO4 particles have weaker backscattering properties than titanium oxide (TiO2) particles or alumina (Al2O3) particles, which scatter light in the opposite direction to the incident direction of the light, and have better forward scattering properties than titanium oxide (TiO2) particles or alumina (Al2O3) particles, which scatter light in the same direction as the incident direction of the light.

[0062] Therefore, white light incident on the transmissive reflective layer 19 of this modified example from the sealing layer 17 is widely scattered and emitted toward the outside of the transmissive reflective layer 19 (upward in Figs. 3 and 4). Furthermore, while suppressing light attenuation within the transmissive reflective layer 19 due to backscattering, it is possible to achieve a batwing light distribution or an inverted triangular light distribution in which the light output of the central part of the batwing light distribution is increased, a so-called inverted umbrella light distribution.

[0063] Even when the configuration of the transflective layer 19 is changed in this way, the light emitting device 100 of this modified example can emit light having a wide-angle light distribution, similar to the light emitting device 100 of the first embodiment.

[0064] [First manufacturing method of light emitting device 100] A first method for manufacturing the light emitting device 100 will be described below with reference to Figures 6 to 10. Figures 6 to 10 are cross-sectional views showing steps in the first method for manufacturing the light emitting device 100. Note that Figures 6 to 10 show, as an example, a partial cross section of a substrate assembly 11M having a plurality of light emitting elements 13 arranged on the upper surface.

[0065] First, a substrate assembly 11M having various wirings is prepared (Step 1: substrate preparation process). Specifically, as shown in Fig. 6, the substrate assembly 11M is prepared in such a manner that the pad body PM before the formation (cutting) of the anode pads 21 and the cathode pads 22 is patterned on the upper surface, the anode electrode 23 and the cathode electrode 24 is patterned on the lower surface, and the conductive vias 25 electrically connecting the pad body PM to the anode electrode 23 and the cathode electrode 24 are formed.

[0066] 6, each of the plurality of light-emitting elements 13 is mounted on the upper surface of the substrate assembly 11M (Step 2: element mounting process). Specifically, epoxy resin solder 33 is applied to the pad body PM, and the light-emitting elements 13 are placed on the applied epoxy resin solder 33, followed by heating at 250°C for 0.5 minutes and then holding at 150°C for 2 hours, thereby mechanically and electrically bonding the light-emitting elements 13 to the pad body PM.

[0067] Next, a phosphor layer 15M encompassing each of the plurality of light-emitting elements 13 is formed on the substrate assembly 11M (Step 3: phosphor layer formation process). Specifically, as shown in FIG. 7, a frame-shaped first dam portion D1 made of resin is formed on the upper surface of the substrate assembly 11M along the outer edge of the substrate assembly 11M, and a predetermined amount of a first precursor resin that will become the phosphor layer 15M is poured into the first dam portion D1. The first precursor resin is then left to stand until it becomes smooth, and then heated and cured at 150°C for 120 minutes to form the phosphor layer 15M. Hereinafter, the molding method of pouring the precursor resin into the dam portion and then heat-curing the precursor resin will be referred to as "cast molding."

[0068] Next, partition grooves are formed on the upper surface of the phosphor layer 15M so as to separate the plurality of light-emitting elements 13 from one another in a top view of the substrate assembly 11M (Step 4: Groove Forming Step). Specifically, using a dicing blade BL1 of a dicer shown in FIG. 7, partition grooves 15MG are formed to separate the plurality of light-emitting elements 13 from one another as shown in FIG.

[0069] At this time, the partition grooves 15MG are formed so that a remaining portion of thickness HR is left from the top surface of the substrate assembly 11M. The frame-shaped portion 15F of the light-emitting device 100 described above is the remaining portion of this partition groove 15MG. The remaining portion is provided so that the wide cutting edge of the dicing blade BL1 does not come into contact with the top surface of the substrate assembly 11M. This is because the wide cutting edge of the dicing blade BL1 would bend the substrate assembly 11M, causing peeling of the phosphor layer 15 or breaking of the light-emitting elements 13.

[0070] Next, the sealing layer 17M that covers the phosphor layer 15M is formed by a casting method (Step 5: sealing layer forming process). Specifically, as shown in Fig. 9, a frame-shaped second dam portion D2 made of resin is formed along the outer edge of the substrate assembly 11M so as to surround the first dam portion D1, and a predetermined amount of second precursor resin that will become the sealing layer 17M is poured into the second dam portion D2.

[0071] This causes the second precursor resin to fill the partitioning grooves 15MG of the phosphor layer 15M. After that, the second precursor resin is left to stand so that it becomes smooth, and then heated and cured at 150°C for 120 minutes to form the sealing layer 17M.

[0072] Next, a transflective layer 19M, which is a dielectric multilayer film, is formed on the upper surface of the sealing layer 17M (Step 6: transflective layer formation process). Specifically, as shown in Fig. 10, the transflective layer 19M is formed by alternately stacking Al2O3 layers and SiO2 layers by atomic layer deposition (ALD) so that the reflectance for white light is about 60%.

[0073] Finally, the plurality of light emitting devices 100 are singulated (Step 7: Singulation Step). Specifically, using a dicing blade BL2 of a dicer shown in Fig. 10, cutting is performed from above the transmissive reflective layer 19M along the partitioning grooves 15MG to the substrate assembly 11M, thereby singulating the plurality of light emitting devices 100. Through the steps described above, the light emitting devices 100 can be manufactured.

[0074] The dicing blade BL2 used to separate the light emitting devices 100 in step 7 is thinner than the dicing blade BL1 used to form the division grooves 15MG in step 4.

[0075] Therefore, a smaller force is applied to the substrate assembly 11M when the dicing blade BL2 is used to separate the light emitting devices 100. This allows the substrate assembly 11M to be cut without causing bending in the substrate assembly 11M.

[0076] In addition, in the above-mentioned step 4, it is desirable that the thickness HR of the phosphor layer 15M (later frame-shaped portion 15F) remaining when the partition groove 15MG is formed is greater than the value (D+σ) obtained by adding the standard deviation (σ) to the average particle size (D) of the phosphor particles with larger particle sizes among the phosphor particles contained in the phosphor layer 15M.

[0077] For example, the average particle size of β-sialon phosphor is 16 μm, which is larger than the average particle size (D) of KSF phosphor, with a standard deviation (σ) of 5 μm. Therefore, the thickness HR is preferably 21 μm or more. Furthermore, the average particle size (D) plus twice the standard deviation (σ) is more preferably 26 μm (D + 2σ), and the average particle size (D) plus three times the standard deviation (σ) is more preferably 31 μm (D + 3σ).

[0078] This is possible because it is possible to prevent phosphor particles from being pinched between the wide cutting edge of the dicing blade BL1 and the upper surface of the substrate assembly 11M during the formation of the partitioning grooves 15MG, and to prevent the pinched phosphor particles from forming cracks in the substrate assembly 11M.It is also possible to prevent the second precursor resin that will become the sealing layer 17M from passing through cracks in the substrate assembly 11M and covering the anode electrodes 23 and cathode electrodes 24 on the lower surface in step 5 (sealing layer forming process).

[0079] If the depth of the dividing grooves 15MG is shallow, the exposed cross section of the frame portion 15F increases when the light emitting device 100 is completed, and the phosphor contained in the phosphor layer 15 may be deteriorated by corrosive gases in the outside air. Therefore, the thickness HR is preferably 1 / 8 or less of the height HP of the phosphor layer 15, and more preferably 1 / 16 or less of the height HP.

[0080] For example, if the height of the phosphor layer 15 is 0.6 mm, the thickness HR is preferably 0.075 (75 μm) or less, more preferably 0.038 mm (38 μm).Also, if the height of the phosphor layer 15 is 0.8 mm, the thickness HR is preferably 0.1 mm (100 μm) or less, more preferably 0.05 mm (50 μm).

[0081] [Improvement of yield during manufacturing of light-emitting devices] As described above, in the manufacturing method of the light emitting device 100 of this embodiment, by leaving the phosphor layer 15 partially uncut when forming the dividing grooves 15MG in step 4, peeling of the phosphor layer 15M from the substrate assembly 11M and disconnection of the light emitting elements 13 can be prevented. In other words, the manufacturing yield can be improved. Furthermore, since cracks can be prevented from forming in the substrate assembly 11M in step 4, the anode electrode 23 and the cathode electrode 24 can be prevented from being covered by the resin of the sealing layer 17M when forming the sealing layer 17M in step 5. This improves the manufacturing yield.

[0082] Therefore, in the first manufacturing method for the light emitting device 100 of this embodiment, bending and cracks are less likely to occur in the substrate assembly 11M. Therefore, according to the first manufacturing method for the light emitting device 100 of this embodiment, the yield rate during manufacturing of the light emitting device 100 can be improved.

[0083] [Method of manufacturing the light emitting device 100 according to the modified example] Next, we will explain a manufacturing method for the modified example of the light emitting device 100. The manufacturing method for the modified example of the light emitting device 100 is the same as the first manufacturing method described above, except for step 6 (transmissive reflective layer forming step).

[0084] In this manufacturing method, the transflective layer 19M is formed on the upper surface of the sealing layer 17M by a casting method. Specifically, a frame-shaped third dam portion D3 (not shown) made of resin is formed along the outer edge of the substrate assembly 11M so as to surround the second dam portion D2, and a predetermined amount of third precursor resin, which is silicone resin with YPO4 particles dispersed therein, is poured into the third dam portion D3. The third precursor resin is then left to stand until it becomes smooth, and then heated and cured at 150°C for 90 minutes to form the transflective layer 19M of the light-emitting device 100 according to the modified example.

[0085] This manufacturing method does not affect the manufacturing processes of steps 4 and 5 described above, and since the phosphor layer 15M, the sealing layer 17M, and the transmissive reflective layer 19M can be formed by a casting method, it is possible to improve the yield during the manufacturing of the light-emitting device 100.

[0086] [Second Method for Manufacturing Light-Emitting Device 100] 11 to 14, a second manufacturing method of the light emitting device 100 will be described. The second manufacturing method differs from the first manufacturing method in that step 3 (phosphor layer forming step), step 5 (sealing layer forming step), and step 6 (transmissive reflective layer forming step) described in the first manufacturing method are performed by insert molding, but the other steps are the same as those of the first manufacturing method.

[0087] Hereinafter, steps 3, 5, and 6 that are different from the first manufacturing method will be described as step 3-2, step 5-2, and step 6-2, respectively.

[0088] [Step 3-2: Phosphor layer formation process] In the phosphor layer formation process of this manufacturing method, as shown in Figure 11, the substrate assembly 11M on which the light-emitting elements 13 have been mounted is sandwiched and held in a first mold 41 consisting of an upper mold 41U and a lower mold 41L having a first space SP1 on the upper surface of the substrate assembly 11M that accommodates multiple light-emitting elements 13.

[0089] 12, the above-described first precursor resin is poured into the first space SP1 formed by the first mold 41. Thereafter, the first mold 41 is heated to a curing temperature to cure the first precursor resin, thereby forming the phosphor layer 15M.

[0090] [Step 5-2: Sealing layer formation process] In the sealing layer formation process of this manufacturing method, as shown in Figure 13, the substrate assembly 11M on which the phosphor layer 15M and the partition groove 15MG have been formed is sandwiched and held in a second mold 42 consisting of an upper mold 42U and a lower mold 42L having a second space SP2 on the upper surface of the substrate assembly 11M to accommodate the phosphor layer 15M.

[0091] 13, the second precursor resin is poured into the second space SP2 formed by the second mold 42. Thereafter, the second mold 42 is heated to a curing temperature to cure the second precursor resin, thereby forming the sealing layer 17M.

[0092] [Step 6-2: Transmissive / reflective layer formation process] In the transmissive-reflective layer forming process of this manufacturing method, as shown in Figure 14, the substrate assembly 11M on which the sealing layer 17M has been formed is sandwiched and held in a third mold 43 consisting of an upper mold 43U and a lower mold 43L having a third space SP3 on the upper surface of the substrate assembly 11M for accommodating the sealing layer 17M.

[0093] 14, the third precursor resin described in the modified example is poured into the third space SP3 formed by the third mold 43. Thereafter, the third mold 43 is heated to a curing temperature to cure the third precursor resin, thereby forming the transmissive reflective layer 19M.

[0094] In steps 3-2, 5-2, and 6-2 of the second manufacturing method, each layer is formed by so-called insert molding (specifically, transfer molding or compression molding). This allows for stable mass production of light emitting devices 100 with high shape accuracy compared to the first manufacturing method, and increases manufacturing throughput.

[0095] Furthermore, in the second manufacturing method, step 4 can be provided between step 3-2 and step 5-2, thereby improving the yield during the manufacturing of the light emitting device 100. In particular, in step 5-2 of the insert molding, a second precursor resin is injected at high pressure onto the upper surface of the substrate assembly 11M on which the phosphor layer 15M and the partition grooves 15MG are formed. Therefore, step 4, which forms the partition grooves 15MG without causing cracks in the substrate assembly 11M, improves the yield during the manufacturing.

[0096] [Third manufacturing method of light emitting device 100] Next, a third manufacturing method of the light emitting device 100 will be described. The third manufacturing method is a manufacturing method in which some of the steps described in the first manufacturing method are replaced with steps of the second manufacturing method. Specifically, in the third manufacturing method, steps 1 to 3, 6, and 7 are the same as those in the first manufacturing method, and only step 5 (a sealing layer forming step) is replaced with step 5-2 of the second manufacturing method.

[0097] The second precursor resin that will become the sealing layer 17M formed in step 5 is a liquid that does not contain any solids and is therefore suitable for insert molding. In addition, the top surface of the sealing layer 17M formed by insert molding is a highly flat surface, which is suitable for forming the transflective layer 19M, which is a dielectric multilayer film.

[0098] That is, in the third manufacturing method, the phosphor layer 15M is formed by pour molding, the sealing layer 17M is formed by insert molding, and the transflective layer 19M is formed by ALD molding.

[0099] The third manufacturing method is a combination of the cast molding of the first manufacturing method and the insert molding of the second manufacturing method. Therefore, the third manufacturing method of the light emitting device 100 enables stable mass production while suppressing manufacturing variations of the light emitting device 100. In other words, the third manufacturing method of the light emitting device 100 improves the balance between manufacturing precision and cost compared to the first and second manufacturing methods.

[0100] In other words, the third manufacturing method is a manufacturing method suitable for forming the phosphor layer 15M, the sealing layer 17M, and the transmissive reflective layer 19M, and can achieve a high yield in each manufacturing step, thereby improving the yield in manufacturing the light-emitting device 100.

[0101] When dividing the light emitting devices 100 into individual pieces in step 7, the substrate aggregate 11M may be cut from the lower surface side with a dicing blade BL2. In this case, by cutting with the dicing blade BL2 using the anode electrode 23 and the cathode electrode 24 formed on the lower surface of the substrate aggregate 11M as markers, it is possible to reduce variation in the external size of the light emitting devices 100.

[0102] As described above in the multiple embodiments, according to the present invention, it is possible to achieve a wide-angle light distribution of emitted light from the light emitting device 100, while improving the yield rate during manufacturing of the light emitting device 100. [Explanation of symbols]

[0103] 11 Circuit Board 13 Light-emitting element 15 Phosphor layer 17 Sealing layer 19 Transmissive reflective layer 21 Anode pad 22 cathode pad 23 Anode electrode 24 cathode electrode 25 Conductive vias 27 Semiconductor structural layer 28 Transparent substrate 31p electrode 32 n electrode 33 Epoxy Resin Solder

Claims

1. A method for manufacturing a light emitting device, comprising: a preparation step of preparing a substrate having a plurality of light emitting elements disposed on an upper surface thereof, each of the light emitting elements including a light emitting layer; a phosphor layer forming step of pouring a first precursor made of a resin in which phosphor particles are dispersed onto the upper surface of the substrate and heat-curing the poured first precursor to form a phosphor layer encompassing the plurality of light-emitting elements; a groove forming step of forming grooves on the upper surface of the phosphor layer so as to separate the plurality of light-emitting elements from each other when viewed from a direction perpendicular to the upper surface; a sealing layer forming step of pouring a second precursor made of a translucent resin onto the upper surface of the phosphor layer and heat-curing the poured second precursor to form a sealing layer; a transflective layer forming step of forming a transflective layer on the sealing layer that reflects a portion of the light emitted from the light-emitting layer and a portion of the fluorescence emitted from the phosphor layer and transmits the light and the fluorescence; a singulation step of cutting the light-emitting device in a depth direction along the grooves from the upper surface of the transmissive reflective layer to the substrate; 1. A method for manufacturing a light emitting device, comprising:

2. 2. The method for manufacturing a light emitting device according to claim 1, wherein a height from an upper surface of the phosphor layer that remains after forming the grooves in the phosphor layer is greater than an average particle size of the phosphor particles.

3. In the phosphor layer forming step, a frame-shaped first dam portion is formed on the upper surface of the substrate along an outer edge of the substrate, and the first precursor is poured into the first dam portion; 2. The method for manufacturing a light-emitting device according to claim 1, wherein in the sealing layer formation process, a frame-shaped second dam portion is formed on the upper surface of the substrate so as to surround the first dam portion along the outer edge of the first dam portion, and the second precursor is poured inside the second dam portion.

4. In the phosphor layer forming step, the substrate is held by a first mold so as to form a first space on an upper surface of the substrate, the first space accommodating a plurality of the light-emitting elements, and the first precursor is poured into the first space; 2. The method for manufacturing a light-emitting device according to claim 1, wherein in the sealing layer forming process, the substrate is held by a second mold so as to form a second space for accommodating the phosphor layer, and the second precursor is poured into the second space.

5. 5. The method for manufacturing a light-emitting device according to claim 3, wherein the transflective layer forming step forms the transflective layer by depositing a dielectric multilayer film by atomic layer deposition.

6. 4. The method for manufacturing a light-emitting device according to claim 3, wherein in the transmissive-reflective layer forming step, a frame-shaped third dam portion is formed on the upper surface of the substrate so as to surround the second dam portion along an outer edge of the second dam portion, a third precursor made of a resin in which light-diffusing particles are dispersed is poured inside the third dam portion, and the poured third precursor is heat-cured to form the transmissive-reflective layer.

7. 5. The method for manufacturing a light-emitting device according to claim 4, wherein in the transflective layer forming step, the substrate is held by a third mold so as to form a third space that accommodates the sealing layer, a third precursor made of a resin in which light-diffusing particles are dispersed is poured into the third space, and the poured third precursor is heat-cured to form the transflective layer.

8. In the phosphor layer forming step, a frame-shaped first dam portion is formed on the upper surface of the substrate along an outer edge of the substrate, and the first precursor is poured into the first dam portion; In the sealing layer forming step, the substrate is held by a second mold so as to form a second space for accommodating the phosphor layer, and the second precursor is poured into the second space; 3. The method for manufacturing a light-emitting device according to claim 1, wherein the transflective layer forming step forms the transflective layer by depositing a dielectric multilayer film by atomic layer deposition.

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