JP7460446B2 - light emitting device - Google Patents

Description

The present invention relates to, for example, a light-emitting device including a light-emitting element.

A light-emitting device includes, for example, a substrate provided with terminals, wiring, etc., at least one light-emitting element mounted on the substrate, and a wavelength converter that converts the wavelength of light emitted from the light-emitting element. include. For example, Patent Document 1 discloses a light-emitting device having a light-emitting element and a wavelength conversion layer.

International Patent Publication No. WO2009/069671

When a light-emitting element and a wavelength converter are bonded using, for example, a transparent adhesive resin, the amount of the adhesive resin applied varies from one light-emitting element to another, and a larger amount than a desired amount may be applied. This may cause the adhesive resin to drip onto the side surface of the light emitting element or creep up onto the side surface of the wavelength converter.

For example, if the adhesive resin drips onto the side of the light-emitting element, the adhesive resin will function as a light guide, and the light emitted from the light-emitting surface of the light-emitting element will be absorbed by the support substrate of the light-emitting element, such as silicon, reducing the light extraction efficiency of the light-emitting device.

In addition, for example, if a large amount of adhesive resin creeps up onto the side of the wavelength converter, color unevenness will occur in the light obtained from the light emitting device. In particular, if the adhesive resin creeps up to the top surface of the wavelength converter, light will be emitted from the light emitting element to the light emitting section of the light emitting device via the creeping adhesive resin, without passing through the wavelength converter, resulting in significant color unevenness due to light leakage.

Therefore, high precision is required in the amount of adhesive resin applied to bond the light emitting element and the wavelength converter.

The present invention has been made in consideration of the above points, and aims to provide a light emitting device and a manufacturing method thereof that can improve the light extraction efficiency of the light emitting device while preventing the adhesive resin from dripping onto the side of the light emitting element and creeping up onto the side of the wavelength conversion body.

The light emitting device according to the present invention includes a mounting substrate, a plurality of light emitting elements each having a support substrate arranged in one direction on the mounting substrate and a semiconductor light emitting layer formed on the upper surface of each of the support substrates, an adhesive resin layer formed on the upper surface of each of the support substrates to cover the semiconductor light emitting layer and extend across the plurality of light emitting elements, and a wavelength conversion plate extending across the plurality of light emitting elements and having a lower surface and an upper surface of each of the plurality of light emitting elements bonded by the adhesive resin layer, and the adhesive resin layer is characterized in that in a region between one adjacent light emitting element and another light emitting element, the adhesive resin layer has a concave portion that extends from an edge of the upper surface of the one light emitting element facing the other light emitting element to an edge of the upper surface of the other light emitting element facing the one light emitting element and includes a downwardly concave surface.

The manufacturing method of the light emitting device according to the present invention includes an element bonding step of bonding at least one power supply wire to an electrode pad formed on a plurality of light emitting elements arranged in one direction on a mounting substrate and forming at least one bump; an application step of applying an adhesive resin layer onto each semiconductor light emitting layer formed on the plurality of light emitting elements; and an adhesion step of adhering a wavelength conversion plate to the lower surface and the upper surface of each of the plurality of light emitting elements by the adhesive resin layer, the adhesive resin layer extending over the plurality of light emitting elements, and being characterized in that in the application step, the adhesive resin layer is formed in a region between the adjacent one light emitting element and the other light emitting element so as to have a concave portion including a downwardly concave surface that extends from the edge of the upper surface of the one light emitting element facing the other light emitting element to the edge of the upper surface of the other light emitting element facing the one light emitting element.

FIG. 2 is a top view of a light emitting device according to an embodiment of the present invention. 2 is a cross-sectional view of the light emitting device taken along line AA in FIG. 3 is an enlarged view of a light emitting element of the light emitting device according to the embodiment of the present invention. 4 is a cross-sectional view of the light-emitting element taken along lines CC and DD in FIG. 3. 2 is an enlarged cross-sectional view of a cavity between adjacent light-emitting elements taken along the line BB of FIG. 1; 1 is a diagram showing a manufacturing flow of a light emitting device according to an example of the present invention. 3A and 3B are top views of the light emitting device during manufacture according to the embodiment of the present invention. 3A and 3B are top views of the light emitting device during manufacture according to the embodiment of the present invention. FIG. 2 is a top view of a light emitting device according to an example of the present invention during manufacture. 3A and 3B are top views of the light emitting device during manufacture according to the embodiment of the present invention. FIG. 2 is a top view of a light emitting device according to an example of the present invention during manufacture. FIG. 3 is a diagram schematically showing wetting and spreading of adhesive resin when a wavelength conversion plate is placed and pressed. 13 is a cross-sectional view of the light-emitting element taken along lines EE and FF in FIG. 12. FIG. 3 is a diagram schematically showing wetting and spreading of adhesive resin when a wavelength conversion plate is placed and pressed. 15 is a cross-sectional view of the light emitting element taken along line GG and line HH in FIG. 14. FIG. 3A and 3B are top views of the light emitting device during manufacture according to the embodiment of the present invention. 3A and 3B are top views of the light emitting device during manufacture according to the embodiment of the present invention. 3A and 3B are top views of the light emitting device during manufacture according to the embodiment of the present invention. FIG. 7 is a top view of a light emitting device according to Modification 1 of the present invention. FIG. 11 is a top view of a light emitting device according to a second modified example of the present invention.

Examples of the present invention will be described in detail below. In the following description and accompanying drawings, substantially the same or equivalent parts are designated by the same reference numerals.

FIG. 1 shows a schematic top view of a light emitting device 10. As shown in FIG. Further, FIG. 2 shows a cross-sectional view of the light emitting device 10 of FIG. 1 taken along line AA.

The light emitting device 10 has a frame 11 in which a concave cavity is formed on one surface. Further, the light emitting device 10 includes a submount 13 housed in a cavity of the frame 11 and a plurality of light emitting elements 20 arranged side by side on the submount 13. Further, the light emitting device 10 includes a wavelength conversion plate 30 integrally formed on each of the plurality of light emitting elements 20.

The body 11 is a substrate that functions as a housing for the light emitting device 10 and has a rectangular planar shape when viewed from above, and is made of a material with high thermal conductivity, such as copper (Cu). The body 11 also has a cavity formed in a concave shape on the upper surface. Although not shown, an insulating film is formed on the upper surface of the body 11, the inside of the cavity, and the outer periphery including the bottom surface, so that the surface of the body 11 is electrically insulated.

The body 11 has a first wiring T1 and a second wiring T2 made of metal formed on the bottom surface of the cavity and the lower surface of the body 11 so as to be spaced apart from each other. Although not shown, the first wiring T1 and the second wiring T2 formed inside the cavity of the body 11 and on the lower surface of the body 11 are each connected by a through electrode. The first wiring T1 and the second wiring T2 on the lower surface side of the body 11 function as external electrodes of the light emitting device 10. In addition, in the through electrodes of the first wiring T1 and the second wiring T2, the junctions between the through electrodes and the body 11 are also joined via an insulating film, and the first wiring T1 and the second wiring T2 are insulated from the body 11. In other words, the first wiring T1 and the second wiring T2 are electrically connected to the part inside the cavity of the body 11 and the part on the lower surface of the body 11, respectively. In addition, the first wiring T1 and the second wiring T2 are insulated from each other and also from the body 11.

In this embodiment, a case will be described in which the main material of the main body 11 is Cu, but the main material of the main body 11 is not limited to this. For example, the frame 11 is made of materials such as ceramics, such as alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), and silicon carbide (SiC), which have high thermal conductivity and insulation properties. may be formed. In this case, it is not necessary to form the above-mentioned insulating film, and it is possible to directly form the first wiring T1 and the second wiring T2, which are metal electrodes, on the bottom surface of the cavity of the body 11 and the lower surface of the body 11. becomes.

The light emitting device 10 also has a submount 13 as a mounting substrate fixed to the bottom surface of the cavity of the body 11. The submount 13 is a substrate having a rectangular planar shape, and is made of a material such as a ceramic having high thermal conductivity, for example, aluminum nitride (AlN). The submount 13 is fixed to the bottom surface of the cavity, for example, with a high thermal conductivity adhesive, not shown. The submount 13, the first wiring T1, and the second wiring T2 are arranged so as to be spaced apart from each other on the bottom surface of the cavity of the body 11.

The submount 13 is also formed with a plurality of metallic wirings PW on which the light-emitting elements 20 are mounted and electrically connected. In this embodiment, a case will be described in which four light-emitting elements 20 are aligned in a row on the submount 13.

Each of the light-emitting elements 20 is, for example, a semiconductor light-emitting element having a light-emitting portion EM as a semiconductor light-emitting layer stacked on a support substrate 21 mainly made of silicon, and is mounted on an element mounting portion (not shown) of the wiring PW of the submount 13. The light-emitting portion EM has a structure in which, for example, a p-type semiconductor layer, a light-emitting layer, and an n-type semiconductor layer are stacked. The upper surface of the n-type semiconductor layer is the upper surface of each of the light-emitting portions EM, and functions as a light extraction surface for each of the light-emitting elements 20. The p-type semiconductor layer, the light-emitting layer, and the n-type semiconductor layer are, for example, nitride semiconductors mainly made of gallium nitride (GaN), etc., and are blue light-emitting diodes (LEDs) that emit blue light from a light-emitting layer having a multiple quantum well structure.

Each of the light-emitting elements 20 has an electrode pad BP formed on the support substrate 21 so as to be spaced apart from the light-emitting portion EM. The electrode pad BP is electrically connected to the p-type semiconductor layer of the light-emitting portion EM and functions as an anode electrode of the light-emitting element 20. The electrode pad BP is electrically connected to the wiring PW of the submount 13 via a conductive bonding wire BW made of gold (Au), for example. The bonding wire BW is configured in a so-called reverse bonding manner, consisting of a wire bump BB and a gold wire W. In this embodiment, the case where the bonding wire BW is reverse bonded will be described, but the manner of the bonding wire BW is not limited to this, and may be a forward bonding manner in which a pressure-bonded ball is formed on the electrode pad BP.

Further, the lower surface of the light emitting element 20 is electrically connected to the n-type semiconductor layer of the light emitting section EM, and the lower surface of the light emitting element 20 functions as a cathode electrode. A cathode electrode, which is the lower surface of the light emitting element 20, is electrically connected to the wiring PW of the submount 13 by, for example, a conductive adhesive material (not shown).

Furthermore, the wiring PW at the left end in FIG. They are electrically connected via wire BW. That is, in this embodiment, the four light emitting elements 20 are connected in series between the first wiring T1 and the second wiring T2 of the frame 11.

Note that in this embodiment, the light emitting portion EM in each of the light emitting elements 20 has a rectangular top surface shape. Further, on the submount 13, each of the light emitting parts EM is arranged in one row, and each of the electrode pads BP is arranged in one row along the arrangement direction of the light emitting parts EM. ing.

The light emitting device 10 has a rectangular planar wavelength conversion plate 30 integrally formed on each of the light emitting elements 20. The wavelength conversion plate 30 performs wavelength conversion on the light emitted from each of the light emitting elements 20. The wavelength conversion plate 30 includes a plate-shaped member including phosphor particles mainly made of YAG doped with cerium (Ce) and a ceramic binder such as glass or alumina. In this embodiment, the wavelength conversion plate 30 is a wavelength conversion plate that performs wavelength conversion on the blue light emitted by the light emitting elements 20 and emits white light.

Moreover, the wavelength conversion plate 30 has a rectangular top surface shape with the long side direction being the arrangement direction of the light emitting elements 20 when viewed from above.

Further, in this embodiment, one of the main surfaces of the wavelength conversion plate 30 is bonded to the upper surface of the light emitting element 20 via an adhesive resin 50 serving as an adhesive resin layer that transmits light emitted by the light emitting element 20. Moreover, the other main surface faces the outside. That is, the one main surface of the wavelength conversion plate 30 functions as a light receiving surface that receives the light emitted by the light emitting element 20 via the adhesive resin 50, and the other main surface functions as a light receiving surface for receiving light emitted by the light emitting element 20, and the other main surface functions as a light receiving surface for receiving light emitted by the light emitting element 20 via the adhesive resin 50. Functions as a surface.

The light emitting device 10 also includes a drain bump (hereinafter sometimes simply referred to as a bump) 40 that sucks the excess adhesive resin 50 when the light emitting element 20 and the wavelength conversion plate 30 are bonded together. Further, each of the bumps 40 is arranged in a line along the arrangement direction of the light emitting parts EM of the light emitting element 20. The bump 40 is, for example, a metal protrusion made of Au, which is the same material as the bonding wire BW. Further, the bumps 40 are formed by a bonding device, and are performed in the same process as bonding of the bonding wires BW.

Further, as shown in FIG. 2, the bumps 40 are formed on the first bump 41 formed on the electrode pad BP, and on the first bump 41, and are located at a center position of the first bump 41. and a second bump 42 formed so as to be offset to the side of the light emitting part EM. The second bump 42 is formed to extend beyond the side of the electrode pad BP on the light emitting part EM side, and the second bump 42 is formed on a wafer protective film (not shown) between the electrode pad BP and the light emitting part EM. It is formed to overhang.

In other words, the light emitting device 10 includes a submount 13, a support substrate 21 disposed on the submount 13, a light emitting element 20 having a light emitting portion EM and an electrode pad BP formed on the support substrate 21, and the submount 13. 13 and the bonding wire BW bonded to the electrode pad BP, the bump 40 formed on the electrode pad BP, the adhesive resin 50 formed on the light emitting part EM of the light emitting element 20, and the bonding wire BW bonded to the electrode pad BP. a wavelength conversion plate 30 disposed so as to cover the light emitting part EM from above the element 20, and the bump 40 has at least a portion extending from the outer edge of the electrode pad BP to the light emitting part EM in a top view. It is formed to protrude to the side.

The bump 40 is composed of a first bump 41 formed on the electrode pad BP and a second bump 42 formed on the first bump 41, the first bump 41 is arranged on the electrode pad BP inside the outer edge of the electrode pad BP, the second bump 42 is arranged so as to be offset from the center position of the first bump 41 on the first bump 41 toward the light emitting unit EM, and at least a part of the second bump 42 is arranged so as to protrude from the outer edge of the electrode pad BP toward the light emitting unit EM in a top view.

Note that the first bump 41 of the bump 40 is offset toward the light emitting part EM on the electrode pad BP from the arrangement direction along the arrangement direction of the light emitting part EM in which the bonding wire BW is formed. Preferably, it is formed. For example, when placing the wavelength conversion plate 30 on the light emitting element 20 (specifically, before the adhesive resin 50 reaches the bumps 40), the wavelength conversion plate 30 is positioned on the electrode pad BP side from the mounting position. If a misalignment occurs, contact with the bonding wire BW can prevent the bonding wire BW from being deformed or disconnected.

Further, as shown in FIGS. 1 and 2, the adhesive resin 50 is formed so as to protrude from the wavelength conversion plate 30 toward the electrode pad BP. In other words, it is formed to cover at least a portion of the bump 40.

Furthermore, the adhesive resin 50 protruding toward the electrode pad BP flows along the outer edge of the electrode pad BP toward the bonding wire BW. The adhesive resin 50 that has reached the bonding wire BW is formed so as to cover the periphery of the bonding wire BW.

Further, as shown in FIG. 2, the light emitting device 10 has a covering member 15 filled in the cavity of the frame 11 so that the upper surface, which is the light extraction surface, of the wavelength conversion plate 30 is exposed. The covering member 15 is made of, for example, a reflective resin material. In this embodiment, the covering member 15 is a white resin that reflects the light emitted by the light emitting element 20. In addition, in FIG. 1, the covering member 15 is omitted in order to clarify the structure and positional relationship of each element in the frame 11.

FIG. 3 is an enlarged view of the light emitting element 20 of the light emitting device 10 according to the embodiment of the present invention. 4 is an enlarged cross-sectional view of the light emitting element 20 taken along line CC and line DD in FIG. 3. The line CC shows a cross section at the position of the bump 40, and the line DD shows a cross section at the position of the bonding wire BW.

As described above, the bump 40 is arranged on the electrode pad BP at a position closer to the light emitting part EM than the bonding wire BW. Further, as shown in FIG. 4, the bumps 40 are two-stage metal bumps including a first bump 41 and a second bump 42 provided on the electrode pad BP of the support substrate 21 in each of the light emitting elements 20. Consisting of Further, the second bump 42 is formed at a position closer to the light emitting part EM than the center position of the first bump 41, and the second bump 42 is formed at a position closer to the light emitting part EM than the center position of the first bump 41. It is formed so as to overhang the membrane CV. Further, as shown in FIG. 4, the bumps 40 are formed so as to be spaced apart from the wavelength conversion plate 30. If the bumps 40 and the wavelength conversion plate 30 come into contact, there is a risk that the electrode pads BP and the protective film CV may be damaged or the mounting position of the wavelength conversion plate 30 may be shifted. It is preferable that

As described above, the support substrate 21 of the light emitting element 20 further includes the protective film CV formed on the support substrate 21 except for the light emitting portion EM and the electrode pad BP, Each of the two bumps 42 is arranged so as to be spaced apart from the protective film CV. Further, the bumps 40 and the wavelength conversion plate 30 are spaced apart from each other. Further, at least a portion of the bump 40 is covered with an adhesive resin 50.

By providing bumps 40 on the electrode pads BP of the light-emitting element 20, when the wavelength conversion plate 30 is placed on the adhesive resin 50 applied to the upper surface of the light-emitting element 20, the excess adhesive resin 50 is sucked from the bumps 40 and stored, making it possible to adjust the amount of adhesive resin 50 used to bond the light-emitting portion EM and the wavelength conversion plate 30 to an appropriate amount.

Specifically, the wavelength conversion plate 30 is placed on the adhesive resin 50 potted on the light emitting portion EM, and the adhesive resin 50 spreads over the joint between the light emitting portion EM and the wavelength conversion plate 30. At this time, the adhesive resin 50 that overflows from the joint is sucked around the bump 40 by capillary action, as shown in the C-C cross section of Figure 4, and the excess adhesive resin 50 is stored.

The excess adhesive resin 50 sucked up by the bump 40 spreads into the electrode pad BP by capillary action, propagating along the outer end of the electrode pad BP, particularly the surface of the electrode pad BP and the side of the protective film CV on the electrode pad BP side. When the adhesive resin 50 that has spread into the electrode pad BP reaches the bonding wire BW, it is sucked up and stored around the bonding wire BW by capillary action, as shown in the D-D cross section.

As a result, when the adhesive resin 50 wets and spreads at the joint between the light-emitting portion EM and the wavelength conversion plate 30, the excess adhesive resin 50 is sucked through the bump 40 and stored around the bump 40 and the bonding wire BW in the electrode pad BP, making it possible to prevent the adhesive resin 50 from dripping onto the side of the light-emitting element 20 or creeping up excessively onto the side of the wavelength conversion plate 30.

In addition, there may be a shortage of adhesive resin 50 due to spreading over the entire surface of the joint between the light emitting unit EM and the wavelength conversion plate 30, particularly at the four corners of the joint that is rectangular in top view. At this time, due to the capillary phenomenon caused by spreading over the four corners, the adhesive resin 50 stored around the bump 40 and the bonding wire BW is resupplied to the joint via the bump 40 in an amount that is insufficient. This allows the light emitting device 10 to adjust the appropriate amount of adhesive resin 50 to spread over the entire surface of the joint between the light emitting unit EM and the wavelength conversion plate 30. In addition, by resupplying the stored adhesive resin 50, it is also possible to prevent excessive creeping up of the adhesive resin 50 from around the bump 40 to the side of the wavelength conversion plate 30.

The adhesive resin 50 along the edge of the lower surface of the wavelength conversion plate 30 forms an end side portion 51 having a concave cross-sectional shape from the end of the edge of the lower surface of the wavelength conversion plate 30 to the end of the edge of the light emitting element 20 corresponding to the edge of the lower surface of the wavelength conversion plate 30. When the adhesive resin 50 spreads by wetting the joint between the light emitting element EM and the wavelength conversion plate 30, the excess adhesive resin 50 is sucked through the bump 40 to the periphery of the bump 40 and the bonding wire BW in the electrode pad BP, forming the concave end side portion 51.

In other words, when the adhesive resin 50 is bonded to the joint between the light emitting portion EM and the wavelength conversion plate 30, the bump 40 has an adhesive resin amount adjustment function that sucks in (drains) excess adhesive resin 50 that may drip onto the side of the light emitting element 20 at the shortest distance from the potting position of the adhesive resin 50 when it wets and spreads, and supplies (re-drains) insufficient adhesive resin 50 that wets and spreads to the four corners of the joint at the longest distance from the potting position.

As described above, the adhesive resin 50 along at least one edge of the wavelength conversion plate 30 has a concave end side portion 51 that extends from the upper surface of the support substrate 21 to the lower surface of the wavelength conversion plate 30.

FIG. 5 is an enlarged sectional view of the BT section showing cavities between adjacent light emitting elements 20 in the BB cross section of FIG.

As described above, due to the adjustment function of the adhesive resin 50 by the bumps 40, the adhesive resin 50 does not drip to the side surface of the light emitting element 20, especially the support substrate 21.

As shown in FIG. 5, the adhesive resin 50 is applied to the inter-element side surface portion 53 extending from the end of the light emitting element 20 toward the wavelength conversion plate 30, and to the bottom surface of the wavelength conversion plate 30 on the surface on the wavelength conversion plate 30 side, as shown in FIG. It has a reverse bend portion 54 as a top surface portion remaining in the form of a thin film, and a tunnel-shaped concave portion 52 formed therein.

The inter-element side portion 53 is formed at an angle inclined from the end of the light-emitting element 20 toward the wavelength conversion plate 30 to the center between adjacent light-emitting elements 20 due to the surface tension of the adhesive resin 50. In addition, the reverse bend portion 54 is formed in the center between adjacent light-emitting elements 20 in a shape (cylindrical shape) having a cross-sectional shape that is convex on the lower surface side.

When the adhesive resin 50 wets and spreads when the wavelength conversion plate 30 is mounted, it wets and spreads over the light emitting element 20 as shown by the broken line in the figure. Thereafter, the excess adhesive resin 50 wetted and spread by the bumps 40 is sucked in the direction of the light emitting elements 20 on the left and right in the figure, so that the adhesive resin 50 remaining in the center between the light emitting elements 20 is removed from the reverse bend portion 54. It is formed in such a shape.

The inter-element side portion 53 and the reverse bend portion 54 have a cross-sectional shape as shown in FIG. 5, and thus have the function of deflecting the radiation light LM emitted from the light-emitting portion EM. In this embodiment, the cavity between the light-emitting elements 20 shown in FIG. 5 is a gas such as air or nitrogen.

For example, when the synchrotron radiation LM is emitted from the light emitting part EM toward the inter-element side surface part 53 and exits from the inter-element side surface part 53, the refractive index of the adhesive resin 50, which is a transparent resin, is larger than that of gas, so The light emitted from the side surface portion 53 is refracted toward the wavelength conversion plate 30 . Furthermore, when the emitted light is incident on the reverse bend section 54, the reverse bend section 54 functions as a convex lens because the reverse bend section 54 has a convex cross-sectional shape on the lower surface. Therefore, the light incident on the reverse bend portion 54 is further refracted in the direction of the wavelength conversion plate 30. As a result, the emitted light LM that does not go directly from the light emitting part EM to the wavelength conversion plate 30 can be guided upward to the light extraction surface of the wavelength conversion plate 30 by the inter-element side surface part 53 and the reverse bend part 54 of the adhesive resin 50. This makes it possible to improve the light extraction efficiency of the light emitting device 10.

In addition, when the mounting height of the upper surface of each of the multiple light-emitting elements 20 arranged on the submount 13, i.e., the height from the upper surface of the submount 13 to the upper surface of each of the multiple light-emitting elements 20 (hereinafter, sometimes simply referred to as the mounting height of the light-emitting element 20), is different, the amount of adhesive resin 50 on the light-emitting element 20 is adjusted by the adjustment function of the adhesive resin 50 by the bump 40 to an amount that balances the surface tension of the adhesive resin 50 applied to the multiple light-emitting elements 20 and the wavelength conversion plate 30. In other words, the bump 40 self-volume controls the amount of adhesive resin 50 according to the mounting height of each of the upper surfaces of the multiple light-emitting elements 20. Therefore, the thickness of the adhesive resin 50 on each of the multiple light-emitting elements 20 is also self-controlled by each bump 40, making it possible to place the wavelength conversion plate 30 horizontally.

As shown in FIG. 5, the light-emitting element 20 is diced so that the angle between the top surface and the side surface is an acute angle on each side. This makes it possible to more reliably prevent the adhesive resin 50 from dripping from the top surface edge of the light-emitting element 20.

As described above, the light emitting device 10 includes a submount 13, a support substrate 21 arranged in one direction on the submount 13, and a plurality of light emitting elements 20 each having a light emitting portion EM formed on the upper surface of each of the support substrates 21, an adhesive resin 50 formed on the upper surface of each of the support substrates 21 to cover the light emitting portion EM and extend across the plurality of light emitting elements 20, and a wavelength conversion plate 30 extending across the plurality of light emitting elements 20 and having its lower surface and the upper surface of each of the plurality of light emitting elements 20 bonded by the adhesive resin 50, and the adhesive resin 50 has a concave portion that extends from the edge of the upper surface of one light emitting element 20 facing the other light emitting element 20 to the edge of the upper surface of the other light emitting element 20 facing the one light emitting element 20 in the region between one adjacent light emitting element 20 and the other light emitting element 20, and includes a concave portion that includes a downwardly concave surface.

Further, the adhesive resin 50 is attached to an inter-element side surface portion extending from an end of the upper surface of the plurality of light emitting elements 20 in the direction of the wavelength conversion plate 30 from one side to the other side of the upper surface of the light emitting elements 20 adjacent to each other. 53 and a reverse bend portion 54 formed in a thin film shape on the lower surface of the wavelength conversion plate 30 between the inter-element side surface portion 53. Further, the reverse bend portion 54 has a downwardly convex cross-sectional shape along the direction 1.

Further, the angle formed between the top surface and the side surface of the support substrate 21 of each of the plurality of light emitting elements 20 is an acute angle.

Next, the manufacturing procedure of the light emitting device 10 according to the embodiment of the present application will be explained using FIG. 6 and FIGS. 7 to 19.

Figure 6 is a diagram showing the manufacturing flow of the light-emitting device 10 according to an embodiment of the present invention. Also, Figures 7 to 19 show top views of the light-emitting device 10 at each step of the manufacturing procedure shown in Figure 6.

First, as shown in FIG. 7, a submount 13 on which a metal element mounting portion and wiring PW are formed is prepared.

Next, as shown in FIG. 8, an adhesive is applied to the element mounting portion, and after the light emitting element 20 is mounted, the light emitting element 20 is fixed (step S11).

As an element bonding process, as shown in FIG. 9, the electrode pad BP of the light-emitting element 20 is bonded to the wiring PW of the submount 13 with a bonding wire BW using a bonding device, and a bump 40 is formed (step S12). As described above, the first bump 41 is formed at a position closer to the light-emitting portion EM than the position where the bonding wire BW is formed in the electrode pad BP, and then the second bump 42 is formed on the first bump 41 so as to overhang from the outer end of the electrode pad BP to the light-emitting portion EM side. In this embodiment, the bump 40 is formed by pressing a gold wire into a ball shape (FAB: Free Air Ball) at the capillary tip of the bonding device against the electrode pad BP or the first bump 41, and then cutting the wire. Next, the electrode pad BP of the light-emitting element 20 and the wiring PW of the submount 13 are electrically connected using a bonding wire BW so that the light-emitting elements 20 are connected in series. Furthermore, since the process for forming the bump 40 and bonding the bonding wire BW is the same, it does not matter which one is formed first.

Next, as a coating process, as shown in FIG. 10, adhesive resin 50 is potted onto the light emitting part EM (step S13).

Next, as a bonding process, as shown in FIG. 11, the wavelength conversion plate 30 is placed so as to cover each of the light-emitting portions EM of the light-emitting elements 20, pressed, and then heated to bond them (step S14).

Here, the behavior of wetting and spreading of the adhesive resin 50 at step S14 and the behavior of sucking, storing, and resupplying the adhesive resin 50 by the bumps 40 will be explained using FIGS. 12 to 15.

FIG. 12 is a diagram schematically showing wetting and spreading of the adhesive resin 50 when the wavelength conversion plate 30 is placed and pressed after the adhesive resin 50 is applied to the light emitting element 20. 13 is an enlarged cross-sectional view of the light emitting element 20 taken along lines EE and FF in FIG. 12. The line EE shows a cross-sectional view at the position of the bump 40, and the line FF shows a cross-sectional view at the position of the bonding wire BW.

The adhesive resin 50 is potted, for example, at the center position of the light emitting part EM by a dispenser. Thereafter, the wavelength conversion plate 30 is placed on the adhesive resin 50, and the wavelength conversion plate 30 is pressed from above.

At this time, when viewed from above, the adhesive resin 50 spreads out, wetting out in a concentric circle from the potting position, as indicated by the dashed arrow in the center of Figure 12.

When the adhesive resin 50 wets and spreads to the end of the light emitting part EM on the electrode pad BP side, the adhesive resin 50 is caused by capillary action as shown by the lower broken line arrow in FIG. 12 and the solid line arrow in the EE cross-sectional view in FIG. It then travels along the bump 40 and is stored around the bump 40.

When the adhesive resin 50 spreads further due to the pressure of the wavelength conversion plate 30, the adhesive resin 50 around the bumps 40 becomes like the lower broken line arrow in FIG. 12 and the solid line arrow in the FF sectional view in FIG. The light then spreads along the edge of the electrode pad BP on the side of the light emitting part EM and extends around the bonding wire BW.

At this time, the height from the electrode pad BP on which the bump 40 is formed is preferably formed so that the bottom surface of the second bump 42 is between the upper surface of the light emitting unit EM and the lower surface of the wavelength conversion plate 30. This allows the bump 40 to efficiently absorb the extruded adhesive resin 50. In other words, the position of the bottom surface of the second bump 42 is positioned higher than the upper surface of the light emitting unit EM and lower than the lower surface of the wavelength conversion plate 30.

As described above, the bump 40 is formed so as to be spaced apart from the wavelength conversion plate 30.

At this time, even if the adhesive resin 50 wets and spreads to the end of the light emitting element 20, the excess adhesive resin 50 dripping on the side surface of the light emitting element 20 is sucked by the bumps 40, so that the light emitting element 20 is It is possible to prevent the adhesive resin 50 from dripping on the side surfaces. That is, when the adhesive resin 50 is spread and extruded by the pressure of the wavelength conversion plate 30, suction of the adhesive resin 50 by the bumps 40 is performed preferentially than dripping of the adhesive resin 50 from the end of the light emitting element 20.

It is also preferable not to press the wavelength conversion plate 30 (including pressing by its own weight) until the adhesive resin 50 spreads over the entire surface of the joint between the light emitting element 20 and the wavelength conversion plate 30. This makes it possible to prevent the wavelength conversion plate 30 from coming into contact with the light emitting portion EM and damaging the light emitting portion EM.

Figure 14 is a schematic diagram showing the spreading of the adhesive resin 50 after pressing the wavelength conversion plate 30. Also, Figure 15 is an enlarged view of the cross section of the light emitting element 20 taken along lines G-G and H-H in Figure 14. Line G-G shows the cross section at the position of the bump 40, and line H-H shows the cross section at the position of the bonding wire BW.

After the wavelength conversion plate 30 is pressed, the adhesive resin 50 spreads over the entire surface of the joint between the light emitting element 20 and the wavelength conversion plate 30 due to capillary action, as shown by the dashed arrow on the light emitting portion EM in FIG. 14. If there is insufficient adhesive resin 50 to spread over the entire surface of the joint between the light emitting element 20 and the wavelength conversion plate 30, the adhesive resin 50 that is pushed out and stored around the bumps 40 and bonding wires BW when the wavelength conversion plate 30 is pressed can be supplied to the joint via the bumps 40 as shown by the lower dashed arrow in FIG. 14 and the solid arrow in FIG. 15, thereby making up for the shortage.

As described above, the adhesive resin 50 is structured not to drip onto the side of the light-emitting element 20, so the placement position of the wavelength conversion plate 30 is self-aligned to the upper surface of the light-emitting element 20 due to the surface tension of the adhesive resin 50. For example, the wavelength conversion plate 30 is self-aligned to the side of the light-emitting element 20 opposite the side where the electrode pad BP is located, and to the side of the light-emitting element 20 corresponding to the short side of the wavelength conversion plate 30. At the same time, if the wavelength conversion plate 30 is in contact with the bump 40, it is separated from it. Also, the adhesive resin 50 is prevented from creeping up onto the wavelength conversion plate 30.

As described above, the submount 13 with the wavelength conversion plate 30 placed on the top surface of the light-emitting element 20 is heated to harden the adhesive resin 50, thereby fixing the wavelength conversion plate 30 to the top surface of the light-emitting element 20.

Next, as shown in FIG. 16, the submount 13 to which the light emitting element 20 and wavelength conversion plate 30 are fixed is fixed to the bottom surface of the cavity of the frame 11 via a high heat conductive adhesive (not shown) (step S15).

As shown in FIG. 17, the wiring PW formed on both ends of the submount 13 is electrically connected to the first wiring T1 and the second wiring T2 formed on the bottom surface of the cavity of the body 11 using bonding wires BW in a bonding device (step S16).

Then, as shown in FIG. 18, the cavity of the body 11 is filled with a reflective covering material 15 to manufacture the light emitting device 10 (step S17).

As described above, the manufacturing method for manufacturing the light emitting device 10 includes bonding the bonding wire BW onto the electrode pad BP formed on the light emitting element 20 disposed on the submount 13 and forming the bump 40 on the element. A bonding process, a coating process of applying adhesive resin 50 onto the light emitting part EM formed on the light emitting element 20, and a wavelength conversion plate 30 disposed on the adhesive resin 50 so as to cover the light emitting part EM from above the light emitting element 20. In the element bonding step, the bump 40 is formed such that at least a portion of the bump 40 protrudes from the outer edge of the electrode pad BP toward the light emitting portion EM when viewed from above. In addition, in the bonding process, the adhesive resin 50 is applied from the edge of the upper surface of one light emitting element 20 facing the other light emitting element 20 to the area between one adjacent light emitting element 20 and another light emitting element 20. It is formed to have a concave portion extending to the edge of the upper surface of the light emitting device 20 facing the first light emitting device 20 and including a downwardly concave surface.

According to this embodiment, the wavelength conversion plate 30 is formed by overhanging the second bump 42 of the bumps 40 on the electrode pad BP of the light emitting element 20 from the outer end of the electrode pad BP to the light emitting part EM. The bumps 40 suck and store excess adhesive resin 50 when placed. This makes it possible to prevent the adhesive resin 50 from dripping onto the side surface of the light emitting element 20.

In addition, after the wavelength conversion plate 30 is pressed, the adhesive resin 50 that was stored when the bumps 40 pressed the wavelength conversion plate 30 is resupplied to compensate for the lack of adhesive resin 50 that has spread over the entire surface of the joint between the light emitting element 20 and the wavelength conversion plate 30. This makes it possible to control the amount of adhesive resin 50 applied to an appropriate level while preventing the adhesive resin 50 from dripping onto the side surface of the light emitting element 20.

In addition, by the bumps 40 absorbing, storing or resupplying the adhesive resin 50, in the layer of adhesive resin 50 between adjacent light emitting elements 20, the bumps 40 form inter-element side portions 53 and reverse bend portions 54 of the adhesive resin 50 that deflect the radiated light LM from the light emitting portion EM to the light extraction surface, which is the upper surface of the wavelength conversion plate 30. This makes it possible to improve the light extraction efficiency of the light emitting device 10.

Therefore, the present invention makes it possible to provide a light emitting device 10 and a manufacturing method thereof that can improve the light extraction efficiency of the light emitting device 10 while preventing the adhesive resin 50 from dripping onto the side surfaces of the light emitting element 20 and creeping up onto the side surfaces of the wavelength conversion plate 30.

In this embodiment, a light emitting device 10 has been described in which bumps 40 are formed on each of a plurality of light emitting elements 20, and a wavelength conversion plate 30 integrally formed across the plurality of light emitting elements 20 is fixed with adhesive resin 50. However, the number of light emitting elements 20 mounted on the light emitting device 10 is not limited to a plurality.

Figure 19 is a top view of a light-emitting device 10A according to variant 1 of the present invention.

The configuration of the light emitting device 10A in the first modification is basically the same as that of the above-described embodiment, but differs from the embodiment in that it has only one light emitting element 20.

Even when the light emitting device 10A has one light emitting element 20 mounted thereon, the bumps 40 can suck, store, and resupply excess adhesive resin 50 when the adhesive resin 50 spreads as the wavelength conversion plate 30A is placed on the light emitting element 20, as in the embodiment.

Further, as in the embodiment, self-volume control of the adhesive resin 50 and self-alignment of the mounting position of the wavelength conversion plate 30 are performed by the bumps 40 formed on the electrode pads BP of the light emitting elements 20.

In addition, in this embodiment, the light emitting device 10 has been described as a light emitting device 10 in which the wavelength conversion plate 30 formed integrally across multiple light emitting elements 20 is fixed with adhesive resin 50. However, the wavelength conversion plate 30 may be mounted individually on each of the light emitting elements 20.

Figure 20 is a top view of a light-emitting device 10B according to variant 2 of the present invention.

The configuration of the light emitting device 10B in the second modification is basically the same as that of the above-described embodiment, but differs from the embodiment in that the wavelength conversion plate 30 placed on the upper surface of the light emitting element 20 is not integrally formed, and wavelength conversion plates 30B, 30C, 30D, and 30E are placed on each of the light emitting elements 20.

Also in the second modification, it is possible to obtain the same effects as in the embodiment.

Further, according to the configuration of Modification 2, for example, the wavelength conversion plates 30B and 30D convert the wavelength to white when excited by the light emitted by the light emitting element 20, and the wavelength conversion plates 30B and 30D convert the wavelength to white when excited by the light emitted from the light emitting element 20, and the wavelength conversion plates 30D convert the wavelength to white when excited by the light emitted from the light emitting element 20, and convert the wavelength to orange when excited by the light emitted from the light emitting element 20. Wavelength conversion plates 30C and 30E that perform wavelength conversion may be alternately arranged. This allows the light emitting device 10 to adjust the color of the light emitted from the light extraction surface of the light emitting device 10. In modification 2, the light emitting elements 20 are connected in series, but in order to enable the plurality of light emitting elements 20 to emit light independently, a plurality of corresponding wirings T1 and T2 are provided in the frame 11, and wavelength conversion plates 30B and 30D, It is also possible to emit white light and orange light by causing the light emitting elements 20 corresponding to the wavelength conversion plates 30C and 30E to emit light separately.

In the present embodiment and variants 1 and 2, the light emitting portion EM of the light emitting element 20 is a blue LED whose main material is a nitride semiconductor. However, the material of the light emitting portion EM is not limited to this, and it can be applied to the semiconductor light emitting layers of various LEDs and lasers that emit light of other colors. Specifically, it is sufficient for the light emitting element 20 to have the light emitting portion EM and the electrode pad BP arranged side by side on the support substrate 21.

Further, in the present embodiment and Modifications 1 and 2, a light emitting device including a wavelength conversion plate 30 that is excited by light emitted from the light emitting element 20 and converts the wavelength of the emitted light has been described. However, the wavelength conversion plate 30 may be a light projection plate that does not convert the wavelength of the light emitted by the light emitting element 20.

Furthermore, in this embodiment and the second modification, the case where the cavity between the adjacent light emitting elements 20 is filled with air or a gas such as nitrogen is described, but the covering member 15 is provided in the cavity between the adjacent light emitting elements 20. May be filled. For example, when the cavity between the light emitting elements 20 is filled with the light reflective covering member 15, the emitted light LM directed from the light emitting part EM toward the inter-element side surface part 53 is reflected, and the inside of the wavelength conversion plate 30 is reflected in the lower surface direction and the lateral direction. Since the light (not shown) propagating in the direction is reflected by the reverse bend portion 54 and polarized toward the surface side of the wavelength conversion plate 30, the light extraction efficiency can be improved. In particular, the efficiency of light extraction from the portion of the wavelength conversion plate 30 corresponding to between the light emitting elements 20 can be improved.

In other words, the inter-element side surface portion 53 of the adhesive resin 50, the reverse bend portion 54, and the side surface of the support substrate 21 are placed between the supporting substrates 21 of the mutually adjacent light emitting devices 20 among the plurality of light emitting devices 20. A covering member 15 made of a light-reflecting material is filled so as to cover it.

As described above, by filling the cover member 15, the cover member 15 reflects the light scattered inside the wavelength conversion plate 30 and emitted to the underside of the light emitting device 10, thereby making it possible to further improve the light extraction efficiency of the light emitting device 10.

10 Light emitting device 11 Body 13 Submount 15 Covering member 20 Light emitting element 21 Support substrate 30 Wavelength conversion plate 40 Bump 41 First bump 42 Second bump 50 Adhesive resin 51 End side surface 52 Concave portion 53 Inter-element side surface 54 Reverse bend part

Claims (5)

A mounting board;
A plurality of light emitting elements each having a support substrate arranged in one direction on the mounting substrate and a semiconductor light emitting layer formed on an upper surface of each of the support substrates;
an adhesive resin layer formed on the upper surface of each of the support substrates so as to cover the semiconductor light emitting layer and extend across the plurality of light emitting elements;
a wavelength conversion plate extending over the plurality of light emitting elements and having a lower surface and an upper surface of each of the plurality of light emitting elements bonded to each other by the adhesive resin layer;
Including,
Each of the plurality of light emitting elements further includes an electrode pad on a surface on which the semiconductor light emitting layer is formed,
At least one power supply wire is bonded to the electrode pad so as to electrically connect the mounting substrate and the electrode pad, and at least one bump is formed on the electrode pad;
The adhesive resin layer is
a concave portion that covers the bump, extends in a region between an adjacent one light emitting element and another light emitting element from an edge of an upper surface of the one light emitting element facing the other light emitting element to an edge of an upper surface of the other light emitting element facing the one light emitting element, and includes a surface that is concave downward;
the concave portion is formed with side portions extending from ends of the upper surfaces of the plurality of light-emitting elements toward the wavelength conversion plate, from one side to the other side facing each other on the upper surfaces of the light-emitting elements adjacent to each other, and a top surface portion formed in a thin film shape on the lower surface of the wavelength conversion plate between the side portions,
The light emitting device , wherein the top surface portion has a cross-sectional shape that is convex downward along the first direction . The wavelength conversion plate has a rectangular planar shape,
The light emitting device according to claim 1 , wherein the adhesive resin layer along at least one side of the wavelength conversion plate has a concave surface extending from an upper surface of the support substrate to a lower surface of the wavelength conversion plate. A reflective material is disposed between the support substrates of each of the light emitting elements adjacent to each other among the plurality of light emitting elements, so as to cover the side surface portion of the adhesive resin layer, the top surface portion, and the side surface of the support substrate. 3. The light emitting device according to claim 1, wherein the light emitting device is filled with a covering member consisting of: The light emitting device according to any one of claims 1 to 3 , wherein an angle formed between an upper surface and a side surface of the support substrate of each of the plurality of light emitting elements is an acute angle. A method for manufacturing a light emitting device, comprising the steps of:
an element bonding step of bonding at least one power supply wire onto an electrode pad formed on a plurality of light emitting elements arranged in one direction on a mounting substrate, and forming at least one bump;
a coating step of coating an adhesive resin layer on each of the semiconductor light emitting layers formed in the plurality of light emitting elements so as to cover the bumps ;
a bonding step of bonding a wavelength conversion plate extending over the plurality of light emitting elements to a lower surface and an upper surface of each of the plurality of light emitting elements by the adhesive resin layer;
Including,
a light-emitting device manufacturing method comprising: in the coating step, the adhesive resin layer has, in a region between adjacent one light-emitting element and another light-emitting element, a concave portion extending from the edge of the upper surface of the one light-emitting element facing the other light-emitting element to the edge of the upper surface of the other light-emitting element facing the one light-emitting element and including a downwardly concave surface; the concave portions are formed, from one side to the other facing side of the upper surfaces of the adjacent light-emitting elements, with side portions extending from the ends of the upper surfaces of the plurality of light-emitting elements toward the wavelength conversion plate; and, between the side portions, a top surface portion formed as a thin film on the lower surface of the wavelength conversion plate; and the top surface portion has a cross-sectional shape that is convex downward along the one direction.

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