Method for manufacturing light-emitting device

Abstract

Provided is a method of manufacturing a light-emitting device, including: preparing a substrate having an upper surface provided with a plurality of light-emitting elements, each of the plurality of light-emitting elements including a light-emitting layer; forming a fluorescent layer including a plurality of light-emitting elements by pouring a first precursor made of a resin in which fluorescent particles are dispersed onto the upper surface of the substrate and thermally curing the poured first precursor; forming a trench on an upper surface of the fluorescent layer so as to be separated from each of the light emitting elements in a plan view from a direction perpendicular to the upper surface; forming a sealing layer by pouring a second precursor made of a translucent resin onto the upper surface of the fluorescent layer and thermally curing the poured second precursor; forming a transmissive reflective layer on the sealing layer, the transmissive reflective layer partially reflecting and partially transmitting each of the light emitted from the light emitting layer and the fluorescent light emitted from the fluorescent layer; the light emitting device is individualized by cutting from an upper surface of the transmissive reflective layer to the substrate in a depth direction along the trench.

Description

Technical Field

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

[0002] A light-emitting device is disclosed, comprising a fluorescent layer of a light-emitting element covered by a transparent resin layer. For example, JP-A-2022-162976 discloses a light-emitting device comprising a light-emitting element disposed on a substrate; a color conversion package containing color conversion particles, the color conversion package being formed to accommodate the light-emitting element on the substrate; and a transparent package made of resin, the transparent package covering the entire color conversion package.

[0003] When manufacturing the light-emitting device disclosed in JP-A-2022-162976, for example, when separating the color conversion package into individual light-emitting devices using a dicing machine after forming the color conversion package, the blade of the dicing machine may reach the substrate.

[0004] If the blade of the dicing machine reaches the substrate when separating the color conversion package as described above, the substrate may become warped, and there is a possibility that the color conversion package may peel off the substrate or the wiring formed on the substrate may break. If this occurs, the yield rate when manufacturing the light-emitting device will decrease.

[0005] The light emitting device disclosed in JP-A-2022-162976 radiates light with a Lambertian distribution. Therefore, in environments requiring light with a wider angle than the Lambertian distribution, such as in auxiliary lighting for vehicles, the light emitting device disclosed in JP-A-2022-162976 may not be used as a light source.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a light-emitting device that can achieve wide-angle light distribution while improving the yield during manufacturing. Summary of the Invention

[0007] The method for manufacturing a light-emitting device according to the present invention includes the following steps: a preparation step of preparing a substrate having an upper surface provided with a plurality of light-emitting elements, each of the plurality of light-emitting elements including a light-emitting layer; a fluorescent layer forming step of forming a fluorescent layer by pouring a first precursor made of a resin in which fluorescent particles are dispersed onto the upper surface of the substrate and thermally curing the poured first precursor, the fluorescent layer including the plurality of light-emitting elements; a groove forming step of forming grooves on the upper surface of the fluorescent layer to separate each of the light-emitting elements when viewed from above 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 fluorescent layer and thermally curing the poured second precursor; a transflective layer forming step of forming a transflective layer on the sealing layer, the transflective layer partially reflecting and partially transmitting each of light emitted from the light-emitting layer and fluorescent light emitted from the fluorescent layer; and an individualization step of individualizing the light-emitting devices by cutting from the upper surface of the transflective layer along the grooves in a depth direction to the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a top view of the light-emitting device of embodiment 1;

[0009] Figure 2 is a bottom view of the light emitting device of embodiment 1;

[0010] Figure 3 is a cross-sectional view of the light-emitting device of Embodiment 1;

[0011] Figure 4 is a cross-sectional view of the light-emitting device of Embodiment 1;

[0012] Figure 5 is a table showing verification results of the light-emitting device according to Embodiment 1;

[0013] Figure 6 1 is a cross-sectional view showing a manufacturing step of a first manufacturing method of the light-emitting device of Embodiment 1;

[0014] Figure 7 1 is a cross-sectional view showing a manufacturing step of a first manufacturing method of the light-emitting device of Embodiment 1;

[0015] Figure 8 1 is a cross-sectional view showing a manufacturing step of a first manufacturing method of the light-emitting device of Embodiment 1;

[0016] Figure 9 1 is a cross-sectional view showing a manufacturing step of a first manufacturing method of the light-emitting device of Embodiment 1;

[0017] Figure 10 4 is a cross-sectional view showing a manufacturing step of a second manufacturing method of the light-emitting device of Embodiment 1;

[0018] Figure 11 4 is a cross-sectional view showing a manufacturing step of a second manufacturing method of the light-emitting device of Embodiment 1;

[0019] Figure 12 4 is a cross-sectional view showing a manufacturing step of a second manufacturing method of the light-emitting device of Embodiment 1;

[0020] Figure 13 is a cross-sectional view showing a manufacturing step of a second manufacturing method of the light-emitting device of Embodiment 1; and

[0021] Figure 14 4 is a cross-sectional view showing a manufacturing step of a second manufacturing method of the light-emitting device of Embodiment 1.

[0022] Description of Reference Numerals

[0023] 11 substrate

[0024] 13 light-emitting elements

[0025] 15 fluorescent layer

[0026] 17 Sealing layer

[0027] 19 Transmissive reflective layer

[0028] 21 anode pad

[0029] 22 cathode pad

[0030] 23 anode electrode

[0031] 24 cathode electrodes

[0032] 25 conductive vias

[0033] 27 semiconductor structure layer

[0034] 28 light-transmitting substrate

[0035] 31 p electrode

[0036] 32 n electrode

[0037] 33 Epoxy Solder DETAILED DESCRIPTION

[0038] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings, substantially the same or equivalent parts are denoted by the same reference numerals, and descriptions of duplicate components are omitted.

[0039] Implementation Method 1

[0040] [Overview of Light Emitting Device 100]

[0041] use Figures 1 to 4The structure of the light-emitting device 100 according to Embodiment 1 will be described. Figure 1 1 is a plan view of the light emitting device 100 according to the first embodiment. Figure 2 This is a bottom view of the light emitting device 100 according to Embodiment 1. Figure 3 It is along Figure 1 3-3 line cross-sectional view of the light emitting device 100 in FIG. Figure 4 It is along Figure 1 4-4 line cross-sectional view of the light emitting device 100 in FIG.

[0042] exist Figure 1 and Figure 2 In the figure, the center line (the line that divides the light emitting device 100 into two parts) in the width direction (the left-right direction in the figure) is indicated by a dotted line as the center line CL1, and the center line (the line that divides the light emitting device 100 into two parts) in the depth direction (the up-down direction in the figure) is indicated by a dotted line as the center line CL2.

[0043] exist Figure 3 In the figure, the left-right direction is the width direction of the light emitting device 100, and the up-down direction is the height direction of the light emitting device 100. Figure 4 , the left-right direction in the figure is the depth direction of the light emitting device 100 , and the up-down direction in the figure is the height direction of the light emitting device 100 .

[0044] like Figure 3 and Figure 4 As shown, the light-emitting device 100 is configured to include a substrate 11, a light-emitting element 13 provided above the substrate 11, a fluorescent layer 15 formed above the substrate 11 to cover the light-emitting element 13, a sealing layer 17 formed to cover the fluorescent layer 15, and a transmissive reflective layer 19 formed on the upper surface of the sealing layer 17.

[0045] [Substrate 11]

[0046] First, substrate 11 will be described. Substrate 11 is a flat glass epoxy substrate (FR-4) with a rectangular upper surface. Substrate 11 has insulating properties. Alternatively, a ceramic substrate made of aluminum oxide (Al2O3) or aluminum nitride (AlN) can be used for substrate 11. An anode pad 21 and a cathode pad 22 are formed on the upper surface of substrate 11. An anode electrode 23 and a cathode electrode 24 are formed on the lower surface of substrate 11.

[0047] The anode pad 21 and the cathode pad 22 are a pair of component mounting pads having a rectangular upper surface shape. The pair of component mounting pads are formed on the upper surface of the substrate 11 and are separated from each other with the center line CL1 therebetween.

[0048] Anode pad 21 has two extensions 21A extending from respective short sides along center line CL1 and reaching the outer edge of substrate 11. Anode pad 21 has two extensions 21B extending from one long side along center line CL2 and reaching the outer edge of substrate 11 with center line CL2 interposed therebetween.

[0049] Similar to anode pad 21, cathode pad 22 has two extensions 22A extending from the corresponding short sides along center line CL1 and reaching the outer edge of substrate 11. Cathode pad 22 has two extensions 22B extending from one long side along center line CL2 and reaching the outer edge of substrate 11 so as to sandwich center line CL2.

[0050] Anode electrode 23 and cathode electrode 24 are a pair of electrodes, each having a rectangular top surface. The pair of electrodes are separated from each other on the lower surface of substrate 11, sandwiching center line CL2. In light-emitting device 100, in a top view of substrate 11 viewed from above, the longitudinal directions of anode pad 21 and cathode pad 22 are orthogonal to the longitudinal directions of anode electrode 23 and cathode electrode 24.

[0051] Each of the anode pad 21, cathode pad 22, anode electrode 23, and cathode electrode 24 is made of copper (Cu) material and has a nickel (Ni) plating layer and a gold (Au) plating layer applied to its surface in sequence. For the electroplating process, silver (Ag) plating can be used instead of Au plating.

[0052] In the light emitting device 100 , the anode pad 21 and the anode electrode 23 are electrically connected via a conductive via 25 made of Cu material. Similarly, the cathode pad 22 and the cathode electrode 24 are electrically connected via a conductive via 25 .

[0053] [Light-emitting element 13]

[0054] Next, a description will be given of the light emitting element 13. As described above, the light emitting element 13 is provided on the upper surface of the substrate 11 and is a light emitting diode (LED) having a rectangular upper surface shape.

[0055] like Figure 3 and Figure 4 As shown, the light emitting element 13 is configured to include a semiconductor structure layer 27 having a light emitting layer composed of a semiconductor, and a light-transmitting substrate 28 provided on the upper surface of the semiconductor structure layer 27 and having light transmissive properties.

[0056] Semiconductor structure layer 27 is a semiconductor stacked structure consisting of an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer (not shown). Each layer is primarily composed of gallium nitride (GaN). When light-emitting element 13 is driven, the light-emitting layer of semiconductor structure layer 27 emits blue light with a peak wavelength of 450 nm.

[0057] The light-transmitting substrate 28 is a flat plate-shaped substrate having a rectangular upper surface. The light-transmitting substrate 28 is made of a material, such as sapphire (Al2O3) or GaN, that is translucent to the blue light emitted from the light-emitting layer of the semiconductor structure layer 27 and the fluorescent light emitted from the fluorescent layer 15, which will be described later. The light-transmitting substrate 28 is also the substrate for growing the semiconductor structure layer 27.

[0058] Light-emitting element 13 includes a p-electrode 31 and an n-electrode 32, each formed on the lower surface of semiconductor structure layer 27, and has a rectangular upper surface shape. P-electrode 31 is an electrode electrically connected to the p-type semiconductor layer of semiconductor structure layer 27. The surface of p-electrode 31 is plated with gold (Au).

[0059] N-electrode 32 is electrically connected to the n-type semiconductor layer via a through-electrode (not shown). This through-electrode vertically penetrates the light-emitting layer and the p-type semiconductor layer of semiconductor structure layer 27 and is laterally covered by an insulator. In other words, n-electrode 32 is electrically connected only to the n-type semiconductor layer and is insulated from the light-emitting layer and the p-type semiconductor layer. The surface of n-electrode 32 is plated with Au.

[0060] P-electrode 31 and n-electrode 32 are connected to anode pad 21 and cathode pad 22, respectively, via epoxy solder 33. In other words, in light-emitting device 100, light-emitting element 13 is flip-chip mounted on substrate 11.

[0061] Epoxy solder 33 contains tin-silver-copper (Sn-Ag-Cu) and other solder metal particles within epoxy flux. After bonding, the epoxy resin coats the area surrounding the solder joint, enhancing bonding strength. Furthermore, since the area surrounding the solder joint is covered with epoxy resin, adhesion to the phosphor layer 15 is improved, making this a preferred method. Gold-tin (Au-Sn) solder using a volatile flux can be used as epoxy solder 33.

[0062] [Fluorescent layer 15]

[0063] Next, the fluorescent layer 15 will be described. The fluorescent layer 15 has a rectangular upper surface shape and is provided on the substrate 11 so as to surround the light-emitting element 13. The fluorescent layer 15 includes a frame-like portion 15F that protrudes laterally from the lower end of the side surface along the upper surface of the substrate 11 and is formed continuously around the periphery of the fluorescent layer 15 when viewed from above. The frame-like portion 15F extends from the lower end of the side surface of the fluorescent layer 15 to the outer edge of the substrate 11.

[0064] The fluorescent layer 15 includes a phosphor that emits fluorescence when excited by blue light as excitation light emitted from the light emitting element 13. When excited by the blue light, the fluorescent layer 15 emits green fluorescence having a peak wavelength in the wavelength range of 500 nm to 580 nm and red fluorescence having a peak wavelength in the wavelength range of 620 nm to 640 nm.

[0065] The fluorescent layer 15 is composed of KSF (K2SiF6:Mn) fluorescent particles emitting red fluorescence and β-Sialon fluorescent particles emitting green fluorescence, which are dispersed in a translucent resin such as silicone resin.

[0066] When blue light emitted from the light emitting element 13 enters the fluorescent layer 15 , a portion thereof directly passes through the fluorescent layer 15 , and a portion thereof excites fluorescent particles, so that fluorescent light is emitted from the excited fluorescent particles.

[0067] Therefore, the excitation light (blue light) that passes through the fluorescent layer 15 and does not contribute to the generation of fluorescence and the fluorescence (green light and red light) emitted from the fluorescent particles are radiated from the upper surface of the fluorescent 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 the fluorescent layer 15.

[0068] [Sealing layer 17]

[0069] Next, the sealing layer 17 will be described. The sealing layer 17 is a translucent layer that covers the upper surface of the fluorescent layer 15. The sealing layer 17 extends from the upper end of the side surface of the fluorescent layer 15 to cover the side surface and terminates at the upper surface of the frame portion 15F. The sealing layer 17 is made of a silicone resin that transmits white light (specifically, white band light).

[0070] The sealing layer 17 covers most of the fluorescent layer 15 and functions as a protective layer to protect the KSF phosphor, which is easily affected by moisture, from the outside air. The sealing layer 17 also functions as a light guide layer to guide the white light emitted from the fluorescent layer 15 .

[0071] [Transmissive reflective layer 19]

[0072] Next, a description will be given of 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 transmits a portion of the white light propagating and emitted through the sealing layer 17 while reflecting a portion.

[0073] In the light-emitting device 100 of this embodiment, the transflective layer 19 is a dielectric multilayer film whose thickness is adjusted so that its reflectivity for white light reaches a predetermined value. Dielectric multilayer films generate both transmitted and reflected light without attenuating incident light, making them suitable for controlling light distribution characteristics (directivity). In the light-emitting device 100, the transflective layer 19 is composed of, for example, 10 to 40 layers (5 to 20 pairs) of alternating silicon oxide (SiO2) and aluminum oxide (Al2O3).

[0074] The material for the transflective layer 19 may be a combination of titanium dioxide (TiO 2 ), niobium oxide (NbO), magnesium oxide (MgO), tantalum oxide (Ta 2 O 5 ), hafnium oxide (HfO), and the like.

[0075] In the light-emitting device 100 of this embodiment, the reflectivity 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 suppressed, while the light intensity to the sides is increased. In other words, the light emitted from the light-emitting device 100 has a wider angular light distribution (half angle of 140° to 180°) than the Lambertian light distribution (half angle of 120°), in which the light intensity decreases from directly above the light-emitting device 100 toward the side surfaces.

[0076] The light emitting device 100 having such a batwing-shaped light distribution can be used in environments where high uniformity of brightness distribution over a wide range is required, such as a light source for vehicle auxiliary lights and a light source for direct backlights for LCD TVs.

[0077] As described above, the fluorescent layer 15 of the light-emitting device 100 of this embodiment includes a frame-shaped portion 15F that is continuously formed around the periphery of the fluorescent layer 15. For example, during the manufacture of the light-emitting device 100, when the fluorescent layer 15 is separated into individual light-emitting devices using a dicer, the fluorescent layer 15 can be processed so as to leave the frame-shaped portion 15F, thereby improving the manufacturing yield (details of which will be described later).

[0078] [verify]

[0079] Here, use Figures 3 to 5 Details and results of verification performed on the light emitting device 100 according to the embodiment will be described. Figure 5 This table shows 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 .

[0080] exist Figure 5Each of the samples B to F differs from the reference sample A in that the height HP of the fluorescent layer 15 from the upper surface of the substrate 11 and the thickness HC of the sealing layer 17 from the upper surface of the fluorescent layer 15 (refer to Figure 3 and Figure 4 ), or the reflectivity of white light of the transmissive reflective layer 19. The thickness of the frame portion 15F from the upper surface of the substrate 11 is defined as a thickness HR.

[0081] This verification used a measurement module in which each 1mm square sample A to F was placed in the center of a 9mm square white housing with an opening at the top. The white housings, each housing containing one sample, were arranged in a 3×3 pattern with no gaps between them, and the light output and brightness of each sample were measured using light radiated from the central white housing.

[0082] Figure 5 The "brightness distribution within the housing" in the table shows the brightness distribution when looking down at the white housing in which samples A to F are placed, and indicates that the darker the color, the higher the brightness. For example, in sample A, it can be seen that the brightness around the light emitting device 100 is the highest.

[0083] in addition, Figure 5 The "brightness ratio" in the table indicates that the closer the value is to 1, the more uniform the brightness of the light in the white housing is. In other words, the higher the brightness ratio, the more uniform the distribution of light in the white housing is.

[0084] [Comparison of samples A, B and C]

[0085] 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), while the thickness HC of the sealing layer 17 (0.1 mm) and the reflectivity of the transflective layer 19 (60%) are identical to each other.

[0086] like Figure 5 As shown, compared to 100% for Sample A, the light output ratio of Sample B increased to 109.5%, and the light output ratio of Sample C increased to 108.4%. The brightness ratio also improved, from 0.748 for Sample A to 0.774 for Sample B and 0.772 for Sample C. In other words, compared to Sample A, both Samples B and C have better light output ratios and brightness ratios.

[0087] [Comparison of samples A, D and E]

[0088] 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), while the height HP of the fluorescent layer 15 (0.4 mm) and the reflectivity of the transflective layer 19 (60%) are identical to each other.

[0089] like Figure 5 As shown, with sample A set to 100%, the light output ratio of sample D is 101.7%, and the light output ratio of sample E is 102.3%. However, compared to 0.748 for sample A, the brightness ratio of sample D is reduced to 0.723, and the brightness ratio of sample E is reduced to 0.692. In other words, samples D and E are superior to sample A in terms of light output ratio, while samples D and E are inferior to sample A in terms of brightness ratio.

[0090] [Comparison of samples A and F]

[0091] The only difference between samples A and F is the reflectivity of the transflective layer 19 (60% and 90%, respectively), while the height HP of the fluorescent layer 15 (0.4 mm) and the thickness HC of the sealing layer 17 (0.1 mm) are identical to each other.

[0092] like Figure 5 As shown, the light output ratio of sample F is 91.5%, which is lower than 100% of sample A. In addition, the brightness ratio of sample F is 0.548, which is lower than 0.748 of sample A. In other words, both the light output ratio and the brightness ratio of sample F are lower than those of sample A.

[0093] [Verification Summary]

[0094] Comparison of samples A, B, and C shows that in a 1 mm square light-emitting device 100, the height HP of the fluorescent layer 15 from the upper surface of the substrate 11 is preferably 0.6 mm to 0.8 mm. In other words, when viewing the light-emitting device 100 from above, the height HP of the fluorescent layer 15 is preferably 60% to 80% of the length of one side of the transflective layer 19.

[0095] Furthermore, based on the comparison results of samples A, D, and E, for a light-emitting device 100 having a square area of ​​1 mm, the thickness HC of the sealing layer 17 from the upper surface of the fluorescent layer 15 is preferably 0.1 mm from the perspective of achieving wide-angle light distribution in the light-emitting device 100. In other words, when viewing the light-emitting device 100 from above, the height HP of the fluorescent layer 15 is preferably 10% of the length of one side of the transflective layer 19.

[0096] Furthermore, based on the comparison results of Samples A and F, in the 1 mm square light-emitting device 100, the reflectivity of the transflective layer 19 for white light is preferably 60%. When the reflectivity of the transflective layer 19 is less than 50%, the central brightness of the white housing increases, and the brightness ratio decreases. Similarly, when the reflectivity of the transflective layer 19 exceeds 70%, the central brightness of the white housing decreases, and the brightness ratio decreases. In other words, the reflectivity of the transflective layer 19 is preferably 60 ± 10%, and more preferably 60 ± 5%.

[0097] As described above, the light emitting device 100 of the embodiment can emit light having a wide-angle light distribution from the light emitting device 100 .

[0098] In the embodiment, the light emitted from the light emitting device 100 is described as having a batwing-like light distribution. However, it is sufficient as long as the light emitted from the light emitting device 100 has a wide-angle light distribution. The light does not necessarily need to have a batwing-like light distribution.

[0099] For example, the reflectivity of the transflective layer 19 for white light in the light emitting device 100 can be set to less than 60%. This allows an umbrella-shaped light distribution or so-called umbrella-shaped light distribution to be obtained as a whole by increasing the light output from directly above the light emitting device 100 compared to a batwing-shaped light distribution and then gradually decreasing it as it moves laterally.

[0100] [Modification of Light Emitting Device 100]

[0101] Next, a description will be given of a modification of Embodiment 1. In this modification, the structure of the transflective layer 19 is different from that of Embodiment 1, but the structures of other parts such as the fluorescent layer 15 and the sealing layer 17 are the same as those of Embodiment 1.

[0102] In this modified example, the transflective layer 19 is formed by dispersing yttrium phosphate (YPO4) particles with a particle size of 1 nm to 5 nm in a silicone resin. Compared to titanium dioxide (TiO2) particles or aluminum oxide (Al2O3) particles, YPO4 particles have weaker backscattering properties, scattering light in the direction opposite to the incident direction, and stronger forward scattering properties, scattering light in the same direction as the incident direction.

[0103] Therefore, the white light entering the transflective layer 19 of the modified example from the sealing layer 17 is reflected in the outer direction of the transflective layer 19 ( Figure 3 、 Figure 4 In addition, while suppressing the attenuation of light within the transflective layer 19 due to backscattering, a so-called reverse umbrella-shaped light distribution can be created, which is an inverted triangular-shaped light distribution that increases the light output of the batwing-shaped light distribution or the central portion of the batwing-shaped light distribution.

[0104] Even when the structure of the transflective layer 19 is changed in this manner, the light-emitting device 100 of the modified example can radiate light with a wide-angle light distribution similar to the light-emitting device 100 of the first embodiment.

[0105] [First Manufacturing Method of Light-Emitting Device 100]

[0106] Use the following Figures 6 to 10 A first manufacturing method for the light emitting device 100 is described. Figures 6 to 10 1 is a cross-sectional view showing steps of a first manufacturing method for the light emitting device 100. As an example, Figures 6 to 10 A partial cross-sectional view of a substrate assembly 11M is shown, which has a plurality of light emitting elements 13 arranged on an upper surface thereof.

[0107] First, a substrate assembly 11M having various wirings is prepared (step 1: substrate preparation step). Specifically, Figure 6 As shown, a substrate assembly 11M is prepared. In the substrate assembly 11M, before the formation of the anode pad 21 and the cathode pad 22 (before cutting), the pad body PM is patterned on its upper surface, the anode electrode 23 and the cathode electrode 24 are patterned on its lower surface, and a conductive through hole 25 is formed to electrically connect the pad body PM to the anode electrode 23 and the cathode electrode 24.

[0108] Next, if Figure 6 As shown, each of the plurality of light-emitting elements 13 is mounted on the upper surface of the substrate assembly 11M (step 2: element mounting step). Specifically, epoxy solder 33 is applied to the pad body PM, and the light-emitting element 13 is placed on the applied epoxy solder 33. The light-emitting element 13 is then mechanically and electrically bonded to the pad body PM by heating at 250°C for 0.5 minutes and then maintaining it at 150°C for 2 hours.

[0109] Next, a fluorescent layer 15M is formed on the substrate assembly 11M so as to surround the corresponding light emitting elements 13 (step 3: fluorescent layer forming step). Figure 7 As shown, a frame-shaped first barrier structure D1 made of resin is formed along the outer edge of the upper surface of the substrate assembly 11M. A predetermined amount of first precursor resin, which will become the fluorescent layer 15M, is poured into the interior of the first barrier structure D1. The first precursor resin is then allowed to settle to smooth the surface and then heated and cured at 150°C for 120 minutes to form the fluorescent layer 15M. This method of pouring the precursor resin into the barrier structure and then thermally curing it is called "cast molding."

[0110] Next, separation grooves are formed on the upper surface of the fluorescent layer 15M so that the substrate assembly 11M is separated into each of the plurality of light emitting elements 13 when viewed from above (step 4: groove forming step). Figure 8 As shown, separation trenches 15MG are formed using Figure 7 The cutting blade BL1 of the illustrated cutting machine separates each of the plurality of light emitting elements 13 .

[0111] At this time, separation grooves 15MG are formed so that a portion corresponding to the thickness HR of the upper surface of substrate assembly 11M remains. The frame-shaped portion 15F of light-emitting device 100 is the remaining portion of these separation grooves 15MG. This remaining portion is arranged so that the wide cutting edge of dicing blade BL1 does not contact the upper surface of substrate assembly 11M. This is because the wide cutting edge of dicing blade BL1 bends substrate assembly 11M, potentially causing separation of phosphor layer 15 or breakage of light-emitting element 13.

[0112] Next, the sealing layer 17M covering the fluorescent layer 15M is formed by casting (step 5: sealing layer forming step). Figure 9 As shown, a frame-shaped second barrier structure D2 made of resin is formed along the outer edge of the substrate assembly 11M to surround the first barrier structure D1, and a predetermined amount of second precursor resin that will become the sealing layer 17M is poured into the interior of the second barrier structure D2.

[0113] This results in the second precursor resin being filled into the separation grooves 15MG of the fluorescent layer 15M. Thereafter, the second precursor resin is allowed to settle and become smooth, and then is thermally cured at 150° C. for 120 minutes to form the sealing layer 17M.

[0114] Next, a transflective layer 19M as a dielectric multilayer film is formed on the upper surface of the sealing layer 17M (step 6: transflective layer forming step). Figure 10 As shown, the transflective layer 19M is formed by alternately stacking Al 2 O 3 layers and SiO 2 layers by atomic layer deposition (ALD), so that the reflectivity with respect to white light is about 60%.

[0115] Finally, each of the plurality of light emitting devices 100 is individualized (step 7: individualization step). Specifically, by using Figure 10 The dicing blade BL2 of the dicing machine shown cuts along the separation grooves 15MG from the top of the transflective layer 19M to the substrate assembly 11M, and each of the plurality of light emitting devices 100 is individualized. The light emitting device 100 can be manufactured through the above steps.

[0116] The dicing blade BL2 used for individualizing the light emitting devices 100 in step 7 has a thinner blade than the dicing blade BL1 used for forming the separation grooves 15MG in step 4 .

[0117] Therefore, when the light emitting device 100 is individualized using the dicing blade BL2, the force applied to the substrate assembly 11M is reduced. Therefore, the substrate assembly 11M can be cut without bending the substrate assembly 11M.

[0118] In the above-mentioned step 4, the thickness HR of the fluorescent layer 15M (hereinafter referred to as the frame-shaped portion 15F) remaining when the separation groove 15MG is formed is preferably larger than the value (D+σ) obtained by adding the standard deviation (σ) to the average particle size (D) of the larger fluorescent particles contained in the fluorescent layer 15M.

[0119] 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, and the standard deviation (σ) is 5 μm. Therefore, the thickness HR is preferably 21 μm or greater. Furthermore, it is more preferably 26 μm (D + 2σ), which is twice the average particle size (D) plus the standard deviation (σ), and even more preferably 31 μm (D + 3σ), which is three times the average particle size (D) plus the standard deviation (σ).

[0120] This is to prevent fluorescent particles from being trapped between the wide cutting edge of the dicing blade BL1 and the upper surface of the substrate assembly 11M during the formation of the separation groove 15MG, thereby preventing the trapped fluorescent particles from forming cracks in the substrate assembly 11M. Furthermore, this is to prevent the second precursor resin, which becomes the sealing layer 17M, from covering the anode electrode 23 and the cathode electrode 24 on the bottom surface through cracks in the substrate assembly 11M in step 5 (sealing layer formation step).

[0121] When the depth of separation trench 15MG is shallow, the exposed cross-section of frame-shaped portion 15F increases when manufacturing light-emitting device 100, and the phosphor contained in fluorescent layer 15 may be degraded by corrosive gases in the external air. Therefore, thickness HR is preferably 1 / 8 or less of height HP of fluorescent layer 15. Even more preferably, it is 1 / 16 or less of height HP.

[0122] For example, when the height of the fluorescent layer 15 is 0.6 mm, the thickness HR is preferably 0.075 mm (75 μm) or less, and more preferably 0.038 mm (38 μm). Furthermore, when the height of the fluorescent layer 15 is 0.8 mm, the thickness HR is preferably 0.1 mm (100 μm) or less, and more preferably 0.05 mm (50 μm).

[0123] [Improvement of Yield During Manufacturing of Light-Emitting Devices]

[0124] As described above, in the method for manufacturing light-emitting device 100 of this embodiment, by preventing a portion of phosphor layer 15 from being cut during the formation of separation trench 15MG in step 4, it is possible to suppress separation of phosphor layer 15M from substrate assembly 11M and disconnection of light-emitting element 13. In other words, this improves the manufacturing yield. Furthermore, since cracks in substrate assembly 11M are suppressed in step 4, the anode electrode 23 and cathode electrode 24 are prevented from being covered by the resin of sealing layer 17M during the formation of sealing layer 17M in step 5. This improves the manufacturing yield.

[0125] Therefore, in the first method for manufacturing the light emitting device 100 of this embodiment, the substrate assembly 11M is less likely to bend or break.

[0126] [Method of Manufacturing Light Emitting Device 100 According to Modification Example]

[0127] Next, a method for manufacturing the light emitting device 100 according to a modification is described. The method for manufacturing the light emitting device 100 according to the modification differs from the first manufacturing method described above only in step 6 (transmissive reflective layer formation step) and is the same as the first manufacturing method in other respects.

[0128] In this manufacturing method, a transflective layer 19M is formed on the upper surface of the sealing layer 17M by casting. Specifically, a frame-shaped third barrier structure D3 (not shown) made of resin is formed along the outer edge of the substrate assembly 11M to surround the second barrier structure D2. A predetermined amount of a third precursor resin (organic silicone resin containing dispersed YPO4 particles) is cast within the third barrier structure D3. After the third precursor resin is allowed to settle and become smooth, it is thermally cured at 150°C for 90 minutes to form the transflective layer 19M of the light-emitting device 100 according to this modification.

[0129] In this manufacturing method, since the manufacturing steps 4 and 5 are not affected and the fluorescent layer 15M, the sealing layer 17M and the transmissive reflective layer 19M can be formed using casting, the yield when manufacturing the light emitting device 100 can be improved.

[0130] [Second Manufacturing Method of Light Emitting Device 100]

[0131] Next, use Figures 11 to 14A second manufacturing method for the light-emitting device 100 will be described. The second manufacturing method differs from the first manufacturing method in that step 3 (fluorescent layer formation step), step 5 (sealing layer formation step), and step 6 (transmissive reflective layer formation step) described in the first manufacturing method are performed using insert molding, and the other steps are the same as those of the first manufacturing method.

[0132] Hereinafter, steps different from step 3, step 5, and step 6 of the first manufacturing method will be described as step 3-2, step 5-2, and step 6-2, respectively.

[0133] [Step 3-2: Fluorescent layer formation step]

[0134] In the fluorescent layer forming step of the manufacturing method, as Figure 11 As shown, the first mold 41 composed of the upper mold 41U and the lower mold 41L clamps the substrate assembly 11M on which the light emitting elements 13 have been mounted. The upper mold 41U has a first space SP1 that accommodates the plurality of light emitting elements 13 on the upper surface of the substrate assembly 11M.

[0135] Then, if Figure 12 As shown, the first precursor resin is poured into the first space SP1 formed by the first mold 41. Thereafter, the first precursor resin is cured by heating the first mold 41 to a curing temperature to form the fluorescent layer 15M.

[0136] [Step 5-2: Sealing layer forming step]

[0137] In the sealing layer forming step of the manufacturing method, as Figure 13 As shown, the substrate assembly 11M having the fluorescent layer 15M and the separation groove 15MG is held by the second mold 42 composed of an upper mold 42U and a lower mold 42L. The upper mold 42U has a second space SP2 for accommodating the fluorescent layer 15M on the upper surface of the substrate assembly 11M.

[0138] Then, if Figure 13 As shown, the second precursor resin is poured into the second space SP2 formed by the second mold 42. Thereafter, the second precursor resin is cured by heating the second mold 42 to a curing temperature to form the sealing layer 17M.

[0139] [Step 6-2: Transmissive Reflective Layer Formation Step]

[0140] In the transflective layer forming step of the manufacturing method, as Figure 14 As shown, the substrate assembly 11M having the sealing layer 17M formed thereon is held by a third mold 43 composed of an upper mold 43U and a lower mold 43L. The upper mold 43U has a third space SP3 for accommodating the sealing layer 17M on the upper surface of the substrate assembly 11M.

[0141] Then, if Figure 14 As shown, the third precursor resin described in the modification is poured into the third space SP3 formed by the third mold 43. Thereafter, the third precursor resin is cured by heating the third mold 43 to a curing temperature to form the transflective layer 19M.

[0142] In the second manufacturing method, steps 3-2, 5-2, and 6-2 are performed to form each layer by insert molding (specifically, transfer molding or compression molding). This allows for stable mass production of light-emitting devices 100 with high shape accuracy and high production throughput compared to the first manufacturing method.

[0143] Furthermore, in the second manufacturing method, step 4 can be provided between step 3-2 and step 5-2, which improves the yield rate when manufacturing the light-emitting device 100. Specifically, in step 5-2 of insert molding, a high-pressure second precursor resin is poured onto the upper surface of the substrate assembly 11M, on which the fluorescent layer 15M and the separation groove 15MG have already been formed. Therefore, by performing step 4 to form the separation groove 15MG in the substrate assembly 11M without generating cracks, the yield rate during manufacturing can be improved.

[0144] [Third Manufacturing Method of Light Emitting Device 100]

[0145] Next, a third manufacturing method for light-emitting device 100 will be described. The third manufacturing method replaces some of the steps described in the first manufacturing method with steps from the second manufacturing method. Specifically, steps 1 to 3, 6, and 7 of the third manufacturing method are the same as those of the first manufacturing method, with only step 5 (sealing layer formation step) replaced with step 5-2 of the second manufacturing method.

[0146] The second precursor resin used to form sealing layer 17M in step 5 is a liquid containing no solids. Therefore, it is suitable for insert molding. Furthermore, the top surface of sealing layer 17M formed by insert molding is a highly precise flat surface, making it suitable for forming transflective layer 19M into a dielectric multilayer film.

[0147] In other words, in the third manufacturing method, the fluorescent layer 15M is formed by cast molding, the sealing layer 17M is formed by insert molding, and the transflective layer 19M is formed by ALD molding.

[0148] The third manufacturing method combines the casting 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 can achieve stable mass production while suppressing manufacturing variations in the light-emitting device 100. In other words, compared to the first and second manufacturing methods, the third manufacturing method of the light-emitting device 100 improves the balance between manufacturing accuracy and cost.

[0149] In other words, the third manufacturing method is suitable for forming the fluorescent layer 15M, the sealing layer 17M, and the transmissive reflective layer 19M. Since a high yield can be achieved in each manufacturing step, the yield when manufacturing the light-emitting device 100 can be improved.

[0150] When the light emitting device 100 is individualized in step 7 as described above, the light emitting device 100 can be cut from the lower side of the substrate assembly 11M with the cutting blade BL2. In this case, the cutting with the cutting blade BL2 is performed using the anode electrode 23 and the cathode electrode 24 formed on the lower side of the substrate assembly 11M as a mark, which reduces the variation in the outer size of the light emitting device 100.

[0151] As described in the above embodiments, the present invention can achieve wide-angle light distribution of the radiated light of the light emitting device 100 while improving the manufacturing yield of the light emitting device 100 .

[0152] It should be understood that the foregoing description and accompanying drawings illustrate preferred embodiments of the present invention. Of course, various modifications, additions, and alternative designs will become apparent to those skilled in the art based on the foregoing teachings without departing from the spirit and scope of the disclosed invention. Therefore, it should be understood that the present invention is not limited to the disclosed examples, but can be practiced within the full scope of the appended claims. This application is based on and claims the benefit of priority of prior Japanese Patent Application No. 2024-047130 filed on March 22, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A method for manufacturing a light-emitting device, the method comprising the following steps: a step of preparing a substrate having an upper surface provided with a plurality of light-emitting elements, each of the plurality of light-emitting elements including a light-emitting layer; a fluorescent layer forming step of pouring a first precursor made of a resin in which fluorescent particles are dispersed onto the upper surface of the substrate and thermally curing the poured first precursor to form a fluorescent layer, wherein the fluorescent layer includes the plurality of light-emitting elements; a groove forming step of forming grooves on the upper surface of the fluorescent layer so as to separate each of the light emitting elements when viewed from a direction perpendicular to the upper surface; a sealing layer forming step of forming the sealing layer by pouring a second precursor made of a translucent resin onto the upper surface of the fluorescent layer and thermally curing the poured second precursor; a transflective layer forming step of forming a transflective layer on the sealing layer, the transflective layer partially reflecting and partially transmitting each of the light emitted from the light emitting layer and the fluorescent light emitted from the fluorescent layer; as well as The individualizing step is to individualize the light emitting device by cutting from the upper surface of the transflective layer along the groove in a depth direction to the substrate.

2. The method for manufacturing a light emitting device according to claim 1, wherein: A remaining portion of the fluorescent layer remaining after the grooves are formed in the fluorescent layer has a height from the upper surface of the substrate greater than an average particle diameter of the fluorescent particles.

3. The method for manufacturing a light emitting device according to claim 1, comprising the following steps: In the fluorescent layer forming step, a frame-shaped first barrier structure is formed on the upper surface of the substrate along the outer edge of the substrate, and the first precursor is poured into the interior of the first barrier structure; as well as In the sealing layer forming step, a frame-shaped second barrier structure is formed on the upper surface of the substrate along the outer edge of the first barrier structure to surround the first barrier structure, and the second precursor is poured into the interior of the second barrier structure.

4. The method for manufacturing a light emitting device according to claim 1, comprising the following steps: In the fluorescent layer forming step, the substrate is held by a first mold to form a first space on the upper surface of the substrate for accommodating the plurality of light-emitting elements, and the first precursor is poured into the first space; as well as In the sealing layer forming step, the substrate is held by a second mold to form a second space for accommodating the fluorescent layer, and the second precursor is poured into the second space.

5. The method for manufacturing a light emitting device according to claim 3, comprising the following steps: In the transflective layer forming step, a dielectric multilayer film is deposited by atomic layer deposition to form the transflective layer.

6. The method for manufacturing a light emitting device according to claim 3, wherein: In the transflective layer forming step, a frame-shaped third barrier structure is formed on the upper surface of the substrate along the outer edge of the second barrier structure to surround the second barrier structure, a third precursor resin in which light scattering particles are dispersed is poured into the third barrier structure, and the poured third precursor resin is thermally cured to form the transflective layer.

7. 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 to form a third space for accommodating the sealing layer, a third precursor resin in which light scattering particles are dispersed is poured into the third space, and the poured third precursor resin is thermally cured to form the transflective layer.

8. The method for manufacturing a light emitting device according to claim 1, wherein: In the fluorescent layer forming step, a frame-shaped first barrier structure is formed on the upper surface of the substrate along the outer edge of the substrate, and the first precursor is poured into the interior of the first barrier structure; In the sealing layer forming step, the substrate is held by a second mold to form a second space for accommodating the fluorescent layer, and the second precursor is poured into the second space; as well as In the transflective layer forming step, a dielectric multilayer film is deposited by atomic layer deposition to form the transflective layer.

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