Light-emitting device and method for manufacturing light-emitting device

Abstract

To provide a light-emitting device in which cracking of extended electrodes is suppressed.SOLUTION: The light-emitting device includes: a light-emitting element 10 having electrodes (a p-side pad electrode 101A and an n-side pad electrode 101B) on a lower surface; a sealing part 11 which is formed of a material using a silicone resin as a base material and covers at least an upper surface and side surfaces of the light-emitting element 10; and extended electrodes 12 which are in contact with the electrodes of the light-emitting element 10 and the sealing part 11 and have larger areas than the electrodes. The extended electrodes 12 are cured products of a conductive paste. The difference between the curing temperature of the conductive paste and the glass transition temperature of the silicone resin is 50°C or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] A light-emitting device called a chip-scale package (CSP) is known. A CSP has a structure in which at least the top surface (the surface opposite the electrode side) and the side of the light-emitting element are covered with a sealing part made of silicone resin, and the electrode on the bottom surface (the surface on the electrode side) is not covered. Since a CSP does not require a lead frame, wires, submounts, etc., it is possible to reduce the size and cost.

[0003] As the CSP becomes smaller, the size of the light-emitting element used also becomes smaller. In addition, when the CSP is mounted on the mounting board, the electrodes of the light-emitting element and the electrodes on the mounting side are directly connected. Therefore, if the size of the electrodes also becomes smaller as the size of the light-emitting element is reduced, the bonding area with the mounting side becomes smaller, and the mounting property decreases.

[0004] Therefore, it is conceivable to improve mountability by forming an extended electrode that is in contact with the electrode of the light-emitting element and the sealing portion and has a larger area than the electrode of the light-emitting element, thereby increasing the bonding area with the outside, as in Patent Document 1. Patent Document 1 describes the use of a conductive paste in which metal powder is dispersed in a resin material or solvent as the extended electrode. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-107285 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the method described in Patent Document 1, cracks may occur in the hardened conductive paste, causing high resistance, or the hardened conductive paste may peel off from the sealing portion.

[0007] The present invention has been made in view of the above background, and aims to provide a light emitting device in which cracks in the conductive paste are suppressed. [Means for solving the problem]

[0008] One aspect of the present invention is A light emitting element having an electrode on a lower surface thereof; a sealing portion formed of a material having a silicone resin as a base material and covering at least an upper surface and a side surface of the light emitting element; an extended electrode in contact with the electrode of the light-emitting element and the sealing portion and having an area larger than that of the electrode; The expanding electrode is a hardened conductive paste, In the light emitting device, the difference between the hardening temperature of the conductive paste and the glass transition temperature of the silicone resin is 50° C. or less.

[0009] Another aspect of the present invention is a light emitting element fixing step of arranging and fixing a light emitting element on a first tape such that an electrode side of the light emitting element is in contact with the first tape; a sealing portion forming step of applying a material having a silicone resin as a base material so as to cover at least the upper surface and the side surface of the light-emitting element and hardening the silicone resin to form a sealing portion; an inversion step of attaching a second tape onto the sealing portion, removing the first tape, and exposing the side that was in contact with the first tape; an extended electrode forming step of applying a conductive paste to a region of the light-emitting element that is in contact with the electrode and the sealing portion and has an area larger than that of the electrode, and hardening the conductive paste by a heat treatment to form an extended electrode; The difference between the hardening temperature of the conductive paste and the glass transition temperature of the silicone resin is 50° C. or less; In the method for manufacturing a light emitting device, a temperature of the heat treatment in the expanding electrode forming step is a hardening temperature of the conductive paste +10° C. or lower. Effect of the Invention

[0010] In the above embodiment, an expanded electrode is provided that is in contact with the electrode of the light-emitting element and the sealing portion and has a larger area than the electrode, the expanded electrode is made of a hardened conductive paste, and the difference between the glass transition temperature of the resin and the hardening temperature of the conductive paste is set to 100° C. or less. This makes it possible to suppress cracks in the expanded electrode due to the difference in linear expansion coefficient. [Brief description of the drawings]

[0011] [Figure 1] 1A and 1B are diagrams illustrating a configuration of a light emitting device according to a first embodiment, in which (a) is a cross-sectional view perpendicular to a main surface of the light emitting device, and (b) is a bottom view of the light emitting device. [Diagram 2] 3A to 3C are diagrams illustrating a manufacturing process of the light emitting device according to the first embodiment. [Diagram 3] 3A to 3C are diagrams illustrating a manufacturing process of the light emitting device according to the first embodiment. [Figure 4] Graph comparing shear strength with and without magnifying electrodes. [Diagram 5] A photograph of the surface of the hardened conductive paste. [Figure 6] FIG. 11 is a diagram showing the configuration of a light emitting device in embodiment 2, illustrating a cross section perpendicular to a main surface of the light emitting device. [Figure 7] FIG. 11 is a diagram showing the configuration of a light emitting device in embodiment 3, and is a diagram showing a cross section perpendicular to a main surface of the light emitting device. [Figure 8] FIG. 13 is a diagram showing the configuration of a light emitting device in embodiment 4, illustrating a cross section perpendicular to a main surface of the light emitting device. [Figure 9] FIG. 13 is a diagram showing the configuration of a light emitting device in embodiment 5, illustrating a cross section perpendicular to a main surface of the light emitting device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The light-emitting device comprises a light-emitting element having an electrode on its underside, a sealing portion formed from a material whose base material is silicone resin and covers at least the upper and side surfaces of the light-emitting element, and an extended electrode that contacts the electrode and sealing portion of the light-emitting element and has a larger area than the electrode, the extended electrode being a hardened conductive paste, and the difference between the hardening temperature of the conductive paste and the glass transition temperature of the silicone resin is 50°C or less.

[0013] In the light emitting device, the silicone resin may have a glass transition temperature of 100° C. or higher, and the conductive paste may have a hardening temperature of 150° C. or lower. This makes it possible to further suppress cracks in the expanded electrode.

[0014] In the light emitting device, the conductive paste may be a Cu paste, which can suppress migration.

[0015] In the light emitting device, the lower surface of the sealing portion may have a notch at an end thereof, and the expanded electrode may be formed along a side surface of the notch, thereby improving adhesion of the expanded electrode.

[0016] In the light emitting device, the light emitting element may have a p-side contact electrode and an n-side contact electrode, and the expansion electrode may be in contact with the p-side contact electrode and the n-side contact electrode. Since the light emitting element does not require a p-side pad electrode or an n-side pad electrode, the configuration of the light emitting device can be further simplified.

[0017] The light emitting device may further include an adhesive layer provided on the upper surface of the sealing portion, and a reflective layer provided on the adhesive layer, thereby increasing the light intensity on the side surface of the light emitting device and decreasing the light intensity on the upper surface.

[0018] The light emitting device may further include a coating film that covers the side and top surfaces of the reflective layer and is made of the same base material as the sealing portion, and the reflective layer may be sealed by the sealing portion and the coating film. Corrosion of the reflective layer can be suppressed.

[0019] The method for manufacturing the light-emitting device includes a light-emitting element fixing process in which a light-emitting element is arranged and fixed on a first tape so that the electrode side of the light-emitting element is in contact with the first tape; a sealing portion forming process in which a material based on silicone resin is applied to cover at least the top and side surfaces of the light-emitting element and the silicone resin is hardened to form a sealing portion; an inversion process in which a second tape is attached onto the sealing portion, the first tape is removed, and the side that was in contact with the first tape is exposed; and an extended electrode forming process in which a conductive paste is applied to an area that is in contact with the electrode of the light-emitting element and the sealing portion and has a larger area than the electrode, and the conductive paste is hardened by heat treatment to form an extended electrode, wherein the difference between the hardening temperature of the conductive paste and the glass transition temperature of the silicone resin is 50°C or less, and the temperature of the heat treatment in the extended electrode forming process is the hardening temperature of the conductive paste + 10°C or less.

[0020] The method for producing a light emitting device described above may further include, after the sealing portion forming step and before the inversion step, a reflective layer forming step of forming an adhesive layer on the sealing portion and forming a reflective layer on the adhesive layer.

[0021] The above-mentioned method for manufacturing a light-emitting device may further include, after the reflective layer forming step and before the inversion step, a coating film forming step of applying a material that is the same base material as the sealing portion so as to cover the upper and side surfaces of the reflective layer and curing the material to form a coating film.

[0022] (Embodiment 1) Fig. 1 is a diagram showing the configuration of a light emitting device of embodiment 1, where (a) is a diagram showing a cross section perpendicular to the main surface of the light emitting device, and (b) is a plan view of the light emitting element viewed from the electrode side. As shown in Fig. 1, the light emitting device of embodiment 1 has a light emitting element 10, a sealing part 11, and two extended electrodes 12. The shape of the light emitting device of embodiment 1 is a rectangular parallelepiped, with the side connected to the mounting board (electrode side) being the bottom surface, the surface opposite to this being the top surface, and the four surfaces perpendicular to the bottom surface and top surface being side surfaces.

[0023] 1. Components of the light-emitting device Each component of the light emitting device in the first embodiment will be described.

[0024] The light emitting element 10 is a blue light emitting element using a group III nitride semiconductor. The light emitting element 10 may be of either a flip chip type or a face up type.

[0025] The light emitting element 10 has a semiconductor layer (not shown) in which an n-type layer, a light emitting layer, and a p-type layer are laminated in this order from the substrate side on a substrate such as sapphire, and has a p-side contact electrode 100A connected to the p-type layer and an n-side contact electrode 100B connected to the n-type layer. Furthermore, a p-side pad electrode 101A and an n-side pad electrode 101B are provided via an insulating film 102, and the p-side contact electrode 100A and the p-side pad electrode 101A are connected, and the n-side contact electrode 100B and the n-side pad electrode 101B are connected, via holes opened in the insulating film 102.

[0026] The light emitting element 10 has a rectangular parallelepiped shape. Hereinafter, the surface on the electrode side of the light emitting element 10 (the side on which the p-side pad electrode 101A and the n-side pad electrode 101B are exposed) will be referred to as the bottom surface of the light emitting element 10, the surface facing the bottom surface as the top surface, and the four surfaces perpendicular to the bottom surface and top surface as side surfaces. The bottom surface and top surface of the light emitting element are, for example, a square or a rectangle. The length of one side of the square (the length of the long side in the case of a rectangle) is, for example, 50 to 300 μm.

[0027] The sealing portion 11 is provided so as to cover the upper surface and the side surfaces of the light-emitting element 10. The sealing portion 11 has a rectangular parallelepiped shape, the upper surface of the sealing portion 11 is a surface parallel to the upper surface of the light-emitting element 10, and the side surfaces of the sealing portion 11 are surfaces parallel to the side surfaces of the light-emitting element 10.

[0028] The sealing portion 11 may be provided to cover the bottom surface of the light emitting element 10 in addition to the top and side surfaces of the light emitting element 10. However, the electrodes of the light emitting element 10 (p-side pad electrode 101A, n-side pad electrode 101B) are covered to a thickness that exposes them. By covering the bottom surface of the light emitting element 10 with the sealing portion 11, it is possible to reduce leakage of blue light from the bottom. In addition, it is possible to increase the holding force of the light emitting element 10 and improve the physical strength. Furthermore, since the extended electrode 12 does not contact the insulating film 102, it is possible to reduce the area with a large difference in linear expansion coefficient in the contact area with the insulating film 102, and it is possible to suppress cracks.

[0029] The bottom and top surfaces of sealing portion 11 are square or rectangular with sides aligned with the bottom and top surfaces of light-emitting element 10. The length of the sides (the length of the longer side in the case of a rectangle) is, for example, 2 to 5 times the length of one side of the bottom and top surfaces of light-emitting element 10, or 150 to 1200 μm. The thickness of sealing portion 11 is, for example, 1.5 to 3 times the thickness of light-emitting element 10, or 50 to 400 μm.

[0030] The sealing portion 11 is formed of a material in which a phosphor and a diffusing material are mixed with a silicone resin as a base material. The phosphor is a yellow phosphor, and is excited by blue light to emit yellow light. A part of the blue light emitted by the light-emitting element 10 is converted into yellow light by the phosphor of the sealing portion 11, so that the light-emitting device of the first embodiment emits white light.

[0031] The glass transition temperature of the silicone resin is, for example, 50 to 120° C., and preferably 100° C. or lower. The linear expansion coefficient of the silicone resin is, for example, 30×10 below the glass transition temperature. -6 ~100×10 -6 / ℃, 150×10 above the glass transition temperature -6 ~500×10 -6 / ℃.

[0032] In the light emitting device in the first embodiment, white light emission is realized by combining the blue light emitting element 10 with a yellow phosphor, but the color of the light emitted by the light emitting device is not limited to this, and the combination of the color of the light emitting element 10 and the phosphor is not limited to this. For example, the light emitted by the light emitting element 10 may be emitted as it is without mixing a phosphor in the sealing portion 11. Also, a red phosphor may be mixed in addition to the yellow phosphor to improve color rendering. Also, an ultraviolet light emitting element may be used as the light emitting element 10, and a blue phosphor, a yellow phosphor, and a red phosphor may be mixed in the sealing portion 11 to realize white light emission.

[0033] The expanded electrode 12 is composed of a p-side expanded electrode 12A connected to the p-side pad electrode 101A, and an n-side expanded electrode 12B connected to the n-side pad electrode 101B.

[0034] The p-side expanded electrode 12A is provided in contact with the p-side pad electrode 101A of the light-emitting element 10 and the sealing part 11, and has a rectangular shape. More specifically, the p-side expanded electrode 12A is in contact with a region of the lower surface of the sealing part 11 that is outside the light-emitting element 10. The area of ​​the p-side expanded electrode 12A is larger than the area of ​​the p-side pad electrode 101A.

[0035] The n-side expanded electrode 12B is provided so as to be in contact with the n-side pad electrode 101B of the light-emitting element 10 and the sealing portion 11, and has a rectangular shape. More specifically, the n-side expanded electrode 12B is in contact with a region of the lower surface of the sealing portion 11 that is outside the light-emitting element 10. The area of ​​the n-side expanded electrode 12B is larger than the area of ​​the n-side pad electrode 101B. The p-side expanded electrode 12A and the n-side expanded electrode 12B are provided at a predetermined distance apart.

[0036] When the sealing portion 11 does not cover the bottom surface of the light-emitting element 10, the expanded electrode 12 also comes into contact with the insulating film 120 of the light-emitting element 10. When the sealing portion 11 covers the bottom surface of the light-emitting element 10, the sealing portion 11 located on the bottom surface of the light-emitting element 10 comes into contact with the expanded electrode 12.

[0037] The reason for providing the extended electrode 12 is as follows. When the light emitting device 10 is small, the areas of the p-side pad electrode 101A and the n-side pad electrode 101B of the light emitting device 10 are also small. Therefore, when the light emitting device is mounted on a mounting substrate, the contact area with the mounting substrate is small, and mountability is deteriorated. Therefore, by providing the extended electrode 12, the joint area with the mounting substrate is enlarged, and mountability is improved.

[0038] The expanded electrode 12 is a hardened conductive paste. The conductive paste is a paste-like material in which metal particles such as Cu, Ag, Au, and Al are dispersed in a resin or solvent, and is a material that is hardened by heat treatment at a temperature equal to or higher than the hardening temperature. Cu paste is preferable from the viewpoints of suppressing migration and reducing costs.

[0039] The difference between the curing temperature of the conductive paste of the expanded electrode 12 and the glass transition temperature of the silicone resin of the sealing portion 11 is set to 50°C or less. The silicone resin of the sealing portion 11 has a larger linear expansion coefficient at or above its glass transition temperature than at temperatures below the glass transition temperature. Therefore, by setting the temperature difference to be within the above range, the temperature range from room temperature to the heat treatment temperature of the expanded electrode 12 that is above the glass transition temperature is reduced, and the linear expansion of the sealing portion 11 is suppressed, thereby reducing the stress generated in the expanded electrode 12 and suppressing the occurrence of cracks in the expanded electrode 12. Preferably, the difference between the curing temperature of the conductive paste of the expanded electrode 12 and the glass transition temperature of the silicone resin of the sealing portion 11 is 30°C or less, more preferably 10°C or less.

[0040] The hardening temperature of the conductive paste of the expanded electrode 12 is, for example, 150° C. or less. The linear expansion coefficient of the expanded electrode 12 is, for example, 10×10 -6 ~100×10 -6 / ℃.

[0041] The thickness of the expanded electrode 12 is, for example, 10 to 50 μm. By setting the thickness within this range, cracks in the expanded electrode 12 can be suppressed and sufficient conductivity can be ensured.

[0042] The area of ​​the p-side expanded electrode 12A and the n-side expanded electrode 12B is 1100 to 971500 μm 2 It is preferable that the bonding area with the mounting board is large, and the mountability can be further improved. For the same reason, it is preferable that the bonding area is 0.02 to 0.43 times the area of ​​the lower surface of the light emitting device.

[0043] 2. Manufacturing method of light-emitting device Next, a method for manufacturing the light emitting device in embodiment 1 will be described with reference to the drawings.

[0044] 2(a), a glass plate 201 is first attached with a UV tape 200 having adhesive surfaces on both sides, and the light emitting elements 10 are arranged on the UV tape 200 and fixed onto the UV tape 200. The light emitting elements 10 are arranged so that the surfaces of the p-side pad electrode 101A and the n-side pad electrode 101B are in contact with the UV tape 200. It is also possible to use only the UV tape 200 without using the glass plate 201.

[0045] 2(b), a material containing silicone resin as a base material is applied so as to cover the upper surface and side surfaces of the light-emitting element 10, and the silicone resin is cured to form the sealing portion 11. At this time, the lower surface of the light-emitting element 10 may be covered with the silicone resin as long as the p-side pad electrode 101A and the n-side pad electrode 101B of the light-emitting element 10 are exposed.

[0046] Next, as shown in Fig. 2(c), tape 202 is applied to the upper surface of the sealing portion 11, ultraviolet light is irradiated onto the UV tape 200 to weaken the adhesion of the UV tape 200, and the UV tape 200 is peeled off from the sealing portion 11, and the glass plate 201 and the UV tape 200 are removed. As a result, the surface that was in contact with the UV tape 200 becomes the exposed surface. Then, as shown in Fig. 2(d), the product is turned upside down so that the exposed surface (the surface on the electrode side) of the light-emitting element 10 becomes the upper surface.

[0047] 3(a), a conductive paste is applied by printing to predetermined regions on the upper surfaces of the light emitting element 10 and the sealing portion 11. For example, a metal mask is placed on the upper surface of the sealing portion 11, the conductive paste is potted on the metal mask, and the conductive paste is moved with a squeegee to push the conductive paste into the openings in the metal mask, thereby applying the conductive paste to the predetermined regions. The conductive paste is then hardened by heat treatment to form the expanded electrode 12.

[0048] Here, the temperature of the heat treatment for hardening the conductive paste is equal to or higher than the hardening temperature of the conductive paste, and is preferably as low as possible, and is preferably equal to or lower than the hardening temperature +10° C. The heat treatment temperature may be the same as the hardening temperature. By reducing the difference between the glass transition temperature of the silicone resin of the sealing portion 11 and the heat treatment temperature, it is possible to suppress cracks in the expanded electrode 12 due to the difference in linear expansion coefficient between the sealing portion 11 and the expanded electrode 12.

[0049] 3(b), sealing portion 11 is cut at predetermined positions with a dicing blade to separate the light emitting devices into individual units. In this manner, the light emitting device of embodiment 1 is manufactured.

[0050] 3. Summary In the light emitting device of the first embodiment, an extended electrode 12 is provided in contact with the pad electrode 101 of the light emitting element 10 and the sealing portion 11, and has an area larger than that of the pad electrode, and the difference between the hardening temperature of the conductive paste of the extended electrode 12 and the glass transition temperature of the silicone resin of the sealing portion 11 is set to 50° C. or less. Therefore, cracks in the extended electrode 12 can be suppressed.

[0051] 4. Experimental results Next, various experimental results regarding the light emitting device of the first embodiment will be described.

[0052] Experiment 1 The die shear strength was compared between the light emitting device of embodiment 1 provided with the expanded electrode 12 and the light emitting device of embodiment 1 omitting the expanded electrode 12. The die shear strength was defined as the force at which the light emitting device peeled off when the light emitting device was mounted on a mounting substrate, a jig was pressed against the light emitting element, and a force was applied horizontally to the light emitting device and in the direction of the long side of the expanded electrode 12. The jig was moved at a speed of 500 μm / s, had a mass of 5 kg, and was positioned 50 μm from the surface of the mounting substrate.

[0053] Figure 4 is a graph comparing the die shear strength. The light emitting device with the expanded electrode 12 weighed 365.16g, while the light emitting device without the expanded electrode 12 weighed 156.16g. This shows that the provision of the expanded electrode 12 improves the mountability.

[0054] Experiment 2 Silicone resin was applied to a portion of the glass plate and cured, and Cu paste was applied to cover the silicone resin, and the Cu paste was cured by heat treatment at 150°C. The thickness of the silicone resin was about 175 μm, and the thickness of the Cu paste was about 60 μm. The silicone resins used had glass transition temperatures of 40°C and 100°C. The Cu paste was formed on the silicone resin to form a rectangular pattern of 6 mm x 46 mm.

[0055] Figure 5 shows micrographs of the sample surfaces, the surface of the glass plate, and the surface of the Cu paste. As shown in Figure 5, no cracks were observed in the Cu paste on silicone resin with a glass transition temperature of 100°C. On the other hand, cracks were observed in the Cu paste on silicone resin with a glass transition temperature of 40°C.

[0056] In addition, when the electrical resistance between both ends of the long side of a 6 mm x 46 mm rectangular area of ​​the Cu paste was measured, the resistance was 0.49 Ω for the Cu paste on silicone resin with a glass transition temperature of 100°C, and 1.50 Ω for the Cu paste on silicone resin with a glass transition temperature of 40°C, indicating that the resistance was high due to the effects of cracks.

[0057] As a result of this experiment, it was found that cracks in the Cu paste can be suppressed by keeping the difference between the glass transition temperature of the silicone resin and the hardening temperature of the Cu paste at 50°C or less.

[0058] (Embodiment 2) 6 is a diagram showing the configuration of a light emitting device in embodiment 2, and is a diagram showing a cross section perpendicular to the main surface of the light emitting device. The light emitting device in embodiment 2 has a cutout 20 provided at the bottom end of the sealing part 11 of the light emitting device in embodiment 1, the p-side expanded electrode 22A and the n-side expanded electrode 22B extending to the cutout 20, and the p-side expanded electrode 22A and the n-side expanded electrode 22B provided along the side and bottom surfaces of the cutout 20. The rest of the configuration is the same as the p-side expanded electrode 12A and the n-side expanded electrode 12B in embodiment 1. This can further improve the adhesion between the p-side expanded electrode 22A and the n-side expanded electrode 22B.

[0059] The notch 20 can be formed by half-dicing a predetermined region of the sealing portion 11 after the step of FIG. 2(d) and before the step of FIG. 3(a).

[0060] (Embodiment 3) 7 is a diagram showing the configuration of a light emitting device in embodiment 3, and is a diagram showing a cross section perpendicular to the main surface of the light emitting device. The light emitting device in embodiment 3 is configured by omitting the p-side pad electrode 101A and the n-side pad electrode 101B from the light emitting element 10 of the light emitting device in embodiment 1, and directly connecting the p-side contact electrode 100A, the n-side contact electrode 100B to the p-side expanded electrode 32A, and the n-side expanded electrode 32B. The rest is the same as the p-side expanded electrode 12A and the n-side expanded electrode 12B in embodiment 1. By thus omitting the p-side pad electrode 101A and the n-side pad electrode 101B from the light emitting element 10, the light emitting device can be further miniaturized and simplified.

[0061] (Embodiment 4) 8 is a diagram showing the configuration of a light emitting device in embodiment 4, and is a diagram showing a cross section perpendicular to the main surface of the light emitting device. The light emitting device in embodiment 4 has a configuration in which a reflective layer 41 is provided on the sealing portion 11 of the light emitting device in embodiment 1 via an adhesive layer 40, and a protective layer 42 is provided on the reflective layer 41.

[0062] The adhesive layer 40 is made of SiO 2 The insulating layer 14 is made of SiO. 2 Other than that, SiN, Al 2 O 3 , AlN, etc. can be used. By providing the adhesion layer 40 between the sealing portion 11 and the reflective layer 41, peeling or cracking of the reflective layer 41 due to the difference in linear expansion coefficient is suppressed, and a decrease in reflectance due to the reflective layer 41 is suppressed. In addition, a product is formed between the sealing portion 11 and the reflective layer 41 when the material of the sealing portion 11 and the material of the reflective layer 41 react with each other, and a decrease in reflectance due to the product is suppressed.

[0063] The thickness of the adhesion layer 40 is preferably 10 nm or more. This is to prevent the adhesion layer 40 from being formed in an island shape, which would cause the sealing portion 11 and the reflective layer 41 to come into contact with each other. In addition, the thickness of the adhesion layer 40 is preferably 300 nm or less. This is because if the adhesion layer 40 is too thick, cracks are more likely to occur in the adhesion layer 40 due to the difference in linear expansion coefficient between the adhesion layer 40 and the sealing portion 11.

[0064] The reflective layer 41 is made of Al or an alloy mainly composed of Al, and is provided on and in contact with the adhesive layer 40. Materials other than Al may be used as long as they have a high reflectance for light having the emission wavelength of the light emitting element 10. For example, Ag or an alloy mainly composed of Ag, Pt, Rh, etc. may be used.

[0065] The thickness of the reflective layer 41 is preferably 50 nm or more. By making the thickness 50 nm or more, the reflectance of the reflective layer 41 can be sufficiently increased. The thickness is more preferably 100 nm or more. Moreover, the thickness of the reflective layer 41 is preferably 300 nm or less. This is because if the reflective layer 41 becomes thick, cracks are more likely to occur in the reflective layer 41 due to the difference in linear expansion coefficient between the reflective layer 41 and the adhesion layer 40.

[0066] The protective layer 42 is provided on and in contact with the reflective layer 41. The protective layer 42 protects the reflective layer 41 and suppresses oxidation of the reflective layer 41. The material of the protective layer 42 is SiO 2 , SiN, Al 2 O 3 , AlN, Ti, Ta, Cr, etc. The adhesive layer 40 and the protective layer 42 may be made of the same material. The thickness of the protective layer 42 is preferably 10 nm or more and 300 nm or less. This is for the same reason as for the preferable range of the adhesive layer 40.

[0067] In the light emitting device of the fourth embodiment, the reflective layer 41 is provided, so that the emission of light from the upper surface of the light emitting device is suppressed, and light is mainly emitted upward from the side surface of the light emitting device. Therefore, the light emitting device of the fourth embodiment has an orientation characteristic of a so-called bat wing shape.

[0068] The adhesive layer 40, the reflective layer 41, and the protective layer 42 are formed by laminating them on the sealing portion 11 by a method such as sputtering or vapor deposition after the step of FIG. 2(b) and before the step of FIG. 2(c).

[0069] (Embodiment 5) 9 is a diagram showing the configuration of a light emitting device in embodiment 5, and is a diagram showing a cross section perpendicular to the main surface of the light emitting device. The light emitting device in embodiment 5 has a configuration in which a notch 51 and a coating film 50 are further added to the light emitting device in embodiment 4.

[0070] The end of the upper surface of the sealing portion 11 has a notch 51 with a depth that reaches the sealing portion 11. The adhesive layer 40, the reflective layer 41, and the protective layer 42 are exposed on the side surface of the notch 51, and the sealing portion 11 is exposed on the bottom surface of the notch 51.

[0071] 9, the coating film 50 is formed on the upper surface of the protective layer 42, and is further formed so as to fill the notch 51. In other words, the side surface of the reflective layer 41 is covered with the coating film 50.

[0072] As a result, the reflective layer 41 has a structure sealed by the sealing portion 11 and the coating film 50. Therefore, it is possible to prevent the reflective layer 41 from reacting with water or the like and corroding, and it is possible to prevent the reflectance of the reflective layer 41 from decreasing.

[0073] The material of the coating film 50 is silicone resin, which is the same as the base material of the sealing portion 11. In particular, modified silicone resin with excellent gas barrier properties is preferable. By using the same base material for the sealing portion 11 and the coating film 50, the adhesion between the sealing portion 11 and the coating film 50 is improved, and corrosion of the reflective layer 41 due to water intrusion from the interface between the sealing portion 11 and the coating film 50 can be suppressed.

[0074] The silicone resin of the coating film 50 may be mixed with particles for controlling the linear expansion coefficient, and it is preferable to minimize the difference in the linear expansion coefficient between the sealing portion 11 and the coating film 50. For example, particles of silica, titanium oxide, carbon black, or the like may be mixed.

[0075] The coating film 50 may be white or black. White can be achieved by mixing particles such as titanium oxide, and black can be achieved by mixing carbon black. By making the coating film 50 white or black, the light emitting device can be made less noticeable when turned off. In addition, light leakage from the upper surface of the coating film 50 can be suppressed.

[0076] When the covering film 50 is provided, the protective layer 42 may be omitted.

[0077] The coating film 50 is formed as follows. First, after the step of FIG. 2(b), the adhesive layer 40, the reflective layer 41, and the protective layer 42 are laminated on the upper surface of the sealing portion 11 in this order from the sealing portion 11 side. Next, a predetermined area is ground by half dicing until the sealing portion 11 is exposed, and a notch 51 is formed. Next, silicone resin is applied to the upper surface of the protective layer 42, and silicone resin is also applied so as to fill the notch 51, and then the silicone resin is cured to form the coating film 50. The subsequent steps are the same as those from the step of FIG. 2(c) onwards. [Explanation of symbols]

[0078] 10: Light emitting element 11: Sealing part 12: Enlarged electrode 12A, 22A, 32A: p-side expanded electrode 12B, 22B, 32B: n-side expanded electrode 100A: p-side contact electrode 100B: n-side contact electrode 101A: p-side pad electrode 101B: n-side pad electrode 102: Insulating film 20, 51: Notch 40: Adhesion layer 41: Reflective layer 42:Protective layer

Claims

1. A light emitting element having an electrode on a lower surface thereof; a sealing portion formed of a material having a silicone resin as a base material and covering at least an upper surface and a side surface of the light emitting element; an extended electrode in contact with the electrode of the light-emitting element and the sealing portion and having an area larger than that of the electrode; The expanding electrode is a hardened conductive paste, A light emitting device, wherein the difference between the hardening temperature of the conductive paste and the glass transition temperature of the silicone resin is 50° C. or less.

2. The silicone resin has a glass transition temperature of 100° C. or higher, The light emitting device according to claim 1 , wherein the conductive paste has a hardening temperature of 150° C. or less.

3. The light emitting device according to claim 1 , wherein the conductive paste is a Cu paste.

4. The light emitting device according to claim 1 , wherein the sealing portion has a lower surface with a notch at an end thereof, and the extended electrode is formed along a side surface of the notch.

5. the light emitting element has a p-side contact electrode and an n-side contact electrode, The light emitting device according to claim 1 , wherein the extension electrode is in contact with the p-side contact electrode and the n-side contact electrode.

6. an adhesion layer provided on an upper surface of the sealing portion; The light emitting device according to claim 1 , further comprising a reflective layer provided on the adhesive layer.

7. The sealing portion is formed of a material that is the same base material as the sealing portion, and the sealing portion further includes a coating film that covers a side surface and an upper surface of the reflective layer, The light emitting device according to claim 6 , wherein the reflective layer is sealed by the sealing portion and the covering film.

8. a light emitting element fixing step of arranging and fixing a light emitting element on a first tape such that an electrode side of the light emitting element is in contact with the first tape; a sealing portion forming step of applying a material having a silicone resin as a base material so as to cover at least the upper surface and the side surface of the light-emitting element and hardening the silicone resin to form a sealing portion; an inversion step of attaching a second tape onto the sealing portion, removing the first tape, and exposing the side that was in contact with the first tape; an extended electrode forming step of applying a conductive paste to a region of the light-emitting element that is in contact with the electrode and the sealing portion and has an area larger than that of the electrode, and hardening the conductive paste by a heat treatment to form an extended electrode; The difference between the hardening temperature of the conductive paste and the glass transition temperature of the silicone resin is 50° C. or less; The method for manufacturing a light emitting device, wherein the temperature of the heat treatment in the expanding electrode forming step is a hardening temperature of the conductive paste plus 10° C. or lower.

9. The method for manufacturing a light emitting device according to claim 8 , further comprising, after the sealing portion forming step and before the inversion step, a reflective layer forming step of forming an adhesive layer on the sealing portion and forming a reflective layer on the adhesive layer.

10. 10. The method for manufacturing a light-emitting device according to claim 9, further comprising a coating film forming step of applying a material, which is the same base material as the sealing portion, so as to cover an upper surface and a side surface of the reflective layer after the reflective layer forming step and before the inversion step, and hardening the material to form a coating film.

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