Light-emitting element for display and LED display device having the same

Abstract

A light emitting device according to one embodiment includes a first light emitting stack including a first conductive type semiconductor layer and a second conductive type semiconductor layer; a second light emitting stack including a first conductive type semiconductor layer and a second conductive type semiconductor layer; a third light emitting stack including a first conductive type semiconductor layer and a second conductive type semiconductor layer; a first adhesive layer bonding the first light emitting stack and the second light emitting stack; and a second adhesive layer bonding the second light emitting stack and the third light emitting stack; wherein the second light emitting stack is disposed between the first light emitting stack and the third light emitting stack, and one of the first adhesive layer and the second adhesive layer is a conductive adhesive layer electrically connecting each light emitting stack adjacent to it.

Description

Technical Field

[0001] The present disclosure relates to a light-emitting element for a display and an LED display device having the same.

Background Art

[0002] Light-emitting diodes are inorganic light sources and are widely used in many fields such as display devices, vehicle lamps, and general lighting. Since light-emitting diodes have the advantages of long lifespan, low power consumption, and fast response speed, they have rapidly replaced existing light sources.

[0003] On the other hand, conventional light-emitting diodes have mainly been used as backlight sources in display devices. However, in recent years, LED displays that directly embody images using light-emitting diodes have been developed.

[0004] Display devices generally embody various hues using a mixture of blue, green, and red colors. A display device includes a plurality of pixels to embody various images, and each pixel includes blue, green, and red sub-pixels. The hue of a specific pixel is determined through the hues of these sub-pixels, and an image is embodied by the combination of these pixels.

[0005] Since LEDs can emit light of various hues depending on their materials, a display device can be provided by arranging individual LED chips that emit blue, green, and red on a two-dimensional plane. However, when arranging one LED chip for each sub-pixel, the number of LED chips increases, and the mounting process takes a lot of time.

[0006] Since the sub-pixels are arranged on a two-dimensional plane, the area occupied by one pixel including blue, green, and red sub-pixels becomes relatively large. Therefore, in order to arrange each sub-pixel within a limited area, the area of each LED chip must be reduced. However, reducing the size of the LED chip may make it difficult to mount the LED chip, and further results in a reduction in the light-emitting area. Summary of the Invention Problems to be Solved by the Invention

[0007] The problem to be solved by the present disclosure is to provide a display device capable of increasing the area of each sub-pixel within a limited pixel area.

[0008] Another problem to be solved by the present disclosure is to provide a display device capable of shortening the mounting process time of the light-emitting element. Means for Solving the Problems

[0009] The light-emitting element according to an embodiment of the present disclosure includes: a first light-emitting stack including a first-conductive-type semiconductor layer and a second-conductive-type semiconductor layer; a second light-emitting stack including a first-conductive-type semiconductor layer and a second-conductive-type semiconductor layer; a third light-emitting stack including a first-conductive-type semiconductor layer and a second-conductive-type semiconductor layer; a first adhesive layer bonding the first light-emitting stack and the second light-emitting stack; and a second adhesive layer bonding the second light-emitting stack and the third light-emitting stack, wherein the second light-emitting stack is disposed between the first light-emitting stack and the third light-emitting stack, and one of the first adhesive layer and the second adhesive layer is a conductive adhesive layer that electrically connects each adjacent light-emitting stack.

[0010] The light-emitting device according to another embodiment of the present disclosure includes: a first light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a second light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a third light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a first adhesive layer that bonds the first light-emitting stack and the second light-emitting stack; a second adhesive layer that bonds the second light-emitting stack and the third light-emitting stack; a first insulating layer that covers the first to third light-emitting stacks; and first to fourth pads disposed on the first insulating layer. The second light-emitting stack and the third light-emitting stack are bonded by the second adhesive layer such that the first-conductivity-type semiconductor layer of the second light-emitting stack and the first-conductivity-type semiconductor layer of the third light-emitting stack are adjacent to each other. The first insulating layer includes a contact hole that exposes both the first-conductivity-type semiconductor layer of the second light-emitting stack and the first-conductivity-type semiconductor layer of the third light-emitting stack. The fourth pad is electrically connected to the first-conductivity-type semiconductor layers of the second and third light-emitting stacks through the contact hole.

[0011] A display device according to an embodiment of the present disclosure includes: a display substrate; a plurality of light-emitting devices disposed on the display substrate; and a molding layer that covers side surfaces of each of the light-emitting devices. The light-emitting device includes: a first light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a second light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a third light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a first adhesive layer that bonds the first light-emitting stack and the second light-emitting stack; and a second adhesive layer that bonds the second light-emitting stack and the third light-emitting stack. The second light-emitting stack is disposed between the first light-emitting stack and the third light-emitting stack, and one of the first adhesive layer and the second adhesive layer is a conductive adhesive layer that electrically connects each adjacent light-emitting stack.

[0012] A display device according to another embodiment of the present disclosure includes a display substrate; a plurality of light-emitting elements disposed on the display substrate; and a molding layer covering side surfaces of each of the light-emitting elements. The light-emitting element includes a first light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a second light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a third light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a first adhesive layer bonding the first light-emitting stack and the second light-emitting stack; a second adhesive layer bonding the second light-emitting stack and the third light-emitting stack; a first insulating layer covering the first to third light-emitting stacks; and first to fourth pads disposed on the first insulating layer. The second light-emitting stack and the third light-emitting stack are bonded by the second adhesive layer such that the first-conductivity-type semiconductor layer of the second light-emitting stack and the first-conductivity-type semiconductor layer of the third light-emitting stack are adjacent to each other. The first insulating layer includes a contact hole exposing the first-conductivity-type semiconductor layer of the second light-emitting stack and the first-conductivity-type semiconductor layer of the third light-emitting stack together. The fourth pad is electrically connected to the first-conductivity-type semiconductor layers of the second and third light-emitting stacks through the contact hole.

Brief Description of the Drawings

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MODE FOR CARRYING OUT THE INVENTION

[0034] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the attached drawings. Each of the embodiments introduced below is provided as an example to sufficiently convey the idea of the present disclosure to those of ordinary skill in the technical field to which the present disclosure pertains. Therefore, the present disclosure is not limited to each of the embodiments described below, and can also be embodied in other forms. And in each drawing, the width, length, thickness, etc. of the components may be exaggerated for convenience. Also, when one component is described as being "above" or "on" another component, it includes not only the case where each part is directly above or directly on another part, but also the case where there are other components intervening between each component and another component. The same reference numerals throughout the specification indicate the same components.

[0035] A light-emitting device according to an embodiment of the present disclosure includes: a first light-emitting stack including a first-conductive-type semiconductor layer and a second-conductive-type semiconductor layer; a second light-emitting stack including a first-conductive-type semiconductor layer and a second-conductive-type semiconductor layer; a third light-emitting stack including a first-conductive-type semiconductor layer and a second-conductive-type semiconductor layer; a first adhesive layer that bonds the first light-emitting stack and the second light-emitting stack; and a second adhesive layer that bonds the second light-emitting stack and the third light-emitting stack. The second light-emitting stack is disposed between the first light-emitting stack and the third light-emitting stack, and one of the first adhesive layer and the second adhesive layer is a conductive adhesive layer that electrically connects each adjacent light-emitting stack.

[0036] Since the first to third light-emitting stacks overlap each other, the pixel area can be increased without increasing the pixel area, and the area of each sub-pixel can be increased within a limited pixel area. Further, since the light-emitting device includes the first to third light-emitting stacks, the number of light-emitting devices can be reduced compared to conventional light-emitting devices, and as a result, the mounting process time of the light-emitting device can be shortened. Further, since one of the first adhesive layer and the second adhesive layer is a conductive adhesive layer that electrically connects each adjacent light-emitting stack, the manufacturing process of the light-emitting device can be simplified.

[0037] In one embodiment, the conductive adhesive layer may include ITO (indium tin oxide). For example, the conductive adhesive layer may be formed using ITO bonding technology.

[0038] In one embodiment, the first, second, and third light-emitting stacks can emit red light, green light, and blue light, respectively. In other embodiments, the first, second, and third light-emitting stacks can emit red light, blue light, and green light, respectively. The second light-emitting stack emits blue light, and the third light-emitting stack emits green light, so that the RGB color mixing ratio can be adjusted by reducing the luminous intensity of blue light and increasing the luminous intensity of green light.

[0039] On the other hand, the light-emitting element may further include a first connection electrode electrically connected to the first light-emitting stack; a second connection electrode electrically connected to the second light-emitting stack; a third connection electrode electrically connected to the third light-emitting stack; and a fourth connection electrode commonly and electrically connected to the first, second, and third light-emitting stacks.

[0040] Furthermore, the fourth connection electrode may be electrically connected to each adjacent light-emitting stack via the conductive adhesive layer.

[0041] In one embodiment, the fourth connection electrode may be commonly and electrically connected to the first conductive type semiconductor layers of the first to third light-emitting stacks, and the first conductive type semiconductor layer may be an n-type semiconductor layer.

[0042] In other embodiments, the fourth connection electrode may be commonly and electrically connected to the second conductive type semiconductor layers of the first to third light-emitting stacks, and the second conductive type semiconductor layer may be a p-type semiconductor layer.

[0043] On the other hand, the light-emitting element may further include a protective layer surrounding at least a part of the first to fourth connection electrodes. The protective layer may include an epoxy molding compound or a polyimide film, and the upper surface of the protective layer may be flush with the upper surfaces of the first to fourth connection electrodes.

[0044] In some embodiments, the light-emitting element may further include a substrate disposed adjacent to the third light-emitting stack.

[0045] A light-emitting element according to another embodiment of the present disclosure includes: a first light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a second light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a third light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a first adhesive layer bonding the first light-emitting stack and the second light-emitting stack; a second adhesive layer bonding the second light-emitting stack and the third light-emitting stack; a first insulating layer covering the first to third light-emitting stacks; and first to fourth pads disposed on the first insulating layer. The second light-emitting stack and the third light-emitting stack are bonded by the second adhesive layer such that the first-conductivity-type semiconductor layer of the second light-emitting stack and the first-conductivity-type semiconductor layer of the third light-emitting stack are adjacent to each other. The first insulating layer includes a contact hole exposing both the first-conductivity-type semiconductor layer of the second light-emitting stack and the first-conductivity-type semiconductor layer of the third light-emitting stack. The fourth pad is electrically connected to the first-conductivity-type semiconductor layers of the second and third light-emitting stacks through the contact hole.

[0046] The first pad may be electrically connected to the second-conductivity-type semiconductor layer of the first light-emitting stack through the first insulating layer, the second pad may be electrically connected to the second-conductivity-type semiconductor layer of the second light-emitting stack through the first insulating layer, the third pad may be electrically connected to the second-conductivity-type semiconductor layer of the third light-emitting stack through the first insulating layer, and the fourth pad may be further electrically connected to the first-conductivity-type semiconductor layer of the first light-emitting stack through the first insulating layer.

[0047] On one hand, the light-emitting element may further include a second insulating layer that covers the first to fourth pads and has through holes for exposing the first to fourth pads; and first to fourth connection electrodes disposed on the second insulating layer and electrically connected to the first to fourth pads through the through holes of the second insulating layer, respectively.

[0048] Also, the light-emitting element may further include a protective layer surrounding at least a part of each of the connection electrodes.

[0049] A display device according to an embodiment of the present disclosure includes a display substrate; a plurality of light-emitting elements disposed on the display substrate; and a molding layer covering side surfaces of each of the light-emitting elements. The light-emitting element includes a first light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a second light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a third light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; a first adhesive layer bonding the first light-emitting stack and the second light-emitting stack; and a second adhesive layer bonding the second light-emitting stack and the third light-emitting stack. The second light-emitting stack is disposed between the first light-emitting stack and the third light-emitting stack, and one of the first adhesive layer and the second adhesive layer is a conductive adhesive layer electrically connecting each adjacent light-emitting stack thereto.

[0050] In one embodiment, the conductive adhesive layer may include ITO.

[0051] On one hand, the light-emitting element may further include a first connection electrode electrically connected to the first light-emitting stack; a second connection electrode electrically connected to the second light-emitting stack; a third connection electrode electrically connected to the third light-emitting stack; and a fourth connection electrode commonly and electrically connected to the first, second, and third light-emitting stacks. The fourth connection electrode may be electrically connected to each adjacent light-emitting stack thereto through the conductive adhesive layer.

[0052] Furthermore, the fourth connection electrode may be electrically connected in common to the first conductivity type semiconductor layers of the first to third light emitting stacks, and the first conductivity type semiconductor layer may be an n-type semiconductor layer.

[0053] A display device according to another embodiment of the present disclosure includes a display substrate; a plurality of light emitting elements disposed on the display substrate; and a molding layer covering side surfaces of each of the light emitting elements. The light emitting element includes a first light emitting stack including a first conductivity type semiconductor layer and a second conductivity type semiconductor layer; a second light emitting stack including a first conductivity type semiconductor layer and a second conductivity type semiconductor layer; a third light emitting stack including a first conductivity type semiconductor layer and a second conductivity type semiconductor layer; a first adhesive layer bonding the first light emitting stack and the second light emitting stack; a second adhesive layer bonding the second light emitting stack and the third light emitting stack; a first insulating layer covering the first to third light emitting stacks; and first to fourth pads disposed on the first insulating layer. The second light emitting stack and the third light emitting stack are bonded by the second adhesive layer such that the first conductivity type semiconductor layer of the second light emitting stack and the first conductivity type semiconductor layer of the third light emitting stack are adjacent to each other. The first insulating layer includes a contact hole exposing both the first conductivity type semiconductor layer of the second light emitting stack and the first conductivity type semiconductor layer of the third light emitting stack. The fourth pad is electrically connected to the first conductivity type semiconductor layers of the second and third light emitting stacks through the contact hole.

[0054] The light emitting element may further include a second insulating layer covering the first to fourth pads and having through holes exposing the first to fourth pads; and first to fourth connection electrodes disposed on the second insulating layer and electrically connected to the first to fourth pads through the through holes of the second insulating layer, respectively.

[0055] Hereinafter, each embodiment of the present disclosure will be specifically described with reference to the drawings. Hereinafter, the light emitting stack structure, the light emitting element, or the light emitting package may include a micro-LED, which, as is known in the art, has a light emitting area of 10000 μm 2The following applies. In other embodiments, the micro-LEDs are 4000 μm 2 or less, and further 2500 μm 2 or less in emission area.

[0056] FIG. 1A is a schematic perspective view for explaining a light-emitting element according to an embodiment of the present disclosure, FIG. 1B is a schematic plan view of the light-emitting element of FIG. 1A, and FIGS. 1C and 1D are schematic cross-sectional views taken along line A-A' and line B-B' of FIG. 1B, respectively.

[0057] Referring to FIGS. 1A and 1B, the light-emitting element 100 includes a light-emitting stack structure, a first connection electrode 20ce, a second connection electrode 30ce, a third connection electrode 40ce, and a fourth connection electrode 50ce formed on the light-emitting stack structure, and a protective layer 90 surrounding each of the connection electrodes 20ce, 30ce, 40ce, 50ce. An array of each light-emitting element 100 may be formed on one substrate, and the light-emitting element 100 exemplarily shown in FIG. 1A shows a single one from the array. The formation and singulation of each light-emitting element 100 will be described in detail later. In some embodiments, the light-emitting element 100 including the light-emitting stack structure may be additionally processed to be formed in a light-emitting package, which will also be described in detail later.

[0058] Referring to FIGS. 1A to 1D, the light-emitting element 100 according to the exemplified embodiment includes a light-emitting stack structure and may include a first LED sub-unit, a second LED sub-unit, and a third LED sub-unit. The first LED sub-unit may include a first light-emitting stack 20, the second LED sub-unit may include a second light-emitting stack 30, and the third LED sub-unit may include a third light-emitting stack 40. The light-emitting stack structure shows three light-emitting stacks 20, 30, 40, but the present disclosure is not limited to a specific number of light-emitting stacks. For example, in some embodiments, the light-emitting stack structure may include two or more light-emitting stacks. Here, the light-emitting element 100 will be described with respect to a light-emitting stack structure including three light-emitting stacks 20, 30, 40 according to an embodiment.

[0059] The substrate 11 is for supporting each of the light-emitting stacks 20, 30, 40, and may be included in the light-emitting element 100, but may ultimately be removed from each of the light-emitting stacks 20, 30, 40. When included in the light-emitting element 100, the substrate 11 may include a light-transmitting insulating material that transmits light. For example, the substrate 11 may include sapphire, glass, quartz, silicon, an organic polymer, or an organic-inorganic composite material, and for example, may be a silicon carbide (SiC), gallium nitride (GaN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), aluminum nitride (AlN), gallium oxide (Ga2O3), or a silicon substrate.

[0060] The first, second, and third light-emitting stacks 20, 30, 40 are configured to emit light toward the substrate 11 or the third lower contact electrode 45p. Thus, the light emitted from the first light-emitting stack 20 can pass through the second and third light-emitting stacks 30, 40. According to one embodiment, the first, second, and third light-emitting stacks 20, 30, 40 can emit light having mutually different peak wavelengths. In one embodiment, the light-emitting stack farther away from the third lower contact electrode 45p can reduce light loss by emitting light having a longer wavelength than the light-emitting stack closer to the third lower contact electrode 45p. For example, the first light-emitting stack 20 can emit red light, the second light-emitting stack 30 can emit green light, and the third light-emitting stack 40 can emit blue light.

[0061] In other embodiments, in order to adjust the color mixing ratio of the first, second, and third light emitting stacks 20, 30, 40, the second light emitting stack 30 can emit light having a wavelength shorter than that of the third light emitting stack 40. Thereby, the luminous intensity of the second light emitting stack 30 can be decreased and the luminous intensity of the third light emitting stack 40 can be increased, and as a result, the luminous intensity ratio of the light emitted from the first, second, and third light emitting stacks can be dramatically changed. For example, the first light emitting stack 20 may be configured to emit red light, the second light emitting stack 30 may be configured to emit blue light, and the third light emitting stack 40 may be configured to emit green light. Thereby, the luminous intensity of the blue light can be relatively decreased and the luminous intensity of the green light can be relatively increased, and as a result, the luminous intensity ratio of red, green, and blue can be easily adjusted to approach 3:6:1. Further, the light emitting areas of the first, second, and third light emitting stacks 20, 30, 40 may be about 10000 μm 2 or less, and further 4000 μm 2 , and further 2500 μm 2 or less. Also, the closer to the third lower contact electrode 45p, the larger the light emitting area becomes, and by arranging the third light emitting stack 40 that emits green light closest to the third lower contact electrode 45p, the luminous intensity of the green light can be further increased.

[0062] The first light emitting stack 20 includes a first conductivity type semiconductor layer 21, an active layer 23, and a second conductivity type semiconductor layer 25. According to one embodiment, the first light emitting stack 20 may include, for example, but not limited to, a semiconductor material that emits red light such as AlGaAs, GaAsP, AlGaInP, and GaP.

[0063] The first upper contact electrode 21n is disposed on the first conductivity type semiconductor layer 21 and can form an ohmic contact with the first conductivity type semiconductor layer 21. The first lower contact electrode 25p may be disposed below the second conductivity type semiconductor layer 25. According to an embodiment, a part of the first conductivity type semiconductor layer 21 may be patterned and recessed, and the first upper contact electrode 21n may be disposed in the recessed region of the first conductivity type semiconductor layer 21 to increase the ohmic contact level. The first upper contact electrode 21n may have a single-layer structure or a multilayer structure and may include Al, Ti, Cr, Ni, Au, Ag, Sn, W, Cu, or alloys thereof, for example, Au-Te alloy or Au-Ge alloy, but is not limited thereto. In one embodiment, the first upper contact electrode 21n may have a thickness of about 100 nm and may include a metal having a high reflectivity to increase the light emission efficiency in the downward direction toward the third lower contact electrode 45p.

[0064] The second light emitting stack 30 includes a first conductivity type semiconductor layer 31, an active layer 33, and a second conductivity type semiconductor layer 35. According to an embodiment, the second light emitting stack 30 may include a semiconductor material that emits blue light such as GaN, InGaN, ZnSe, etc., but is not limited thereto. The second lower contact electrode 35p is disposed on the second conductivity type semiconductor layer 35 of the second light emitting stack 30.

[0065] The third light emitting stack 40 includes a first conductivity type semiconductor layer 41, an active layer 43, and a second conductivity type semiconductor layer 45. According to an embodiment, the third light emitting stack 40 may include a semiconductor material that emits green light such as GaN, InGaN, GaP, AlGaInP, AlGaP, etc. The third lower contact electrode 45p is disposed below the second conductivity type semiconductor layer 45 of the third light emitting stack 40. As described above, the semiconductor materials of the second light emitting stack 30 and the third light emitting stack 40 may be replaced with each other.

[0066] According to one embodiment, each of the first conductive type semiconductor layers 21, 31, 41 and the second conductive type semiconductor layers 25, 35, 45 of the first, second and third light emitting stacks 20, 30, 40 may have a single layer structure or a multilayer structure, and in some embodiments, may include a superlattice layer. Further, each of the active layers 23, 33, 43 of the first, second and third light emitting stacks 20, 30, 40 may have a single quantum well structure or a multiple quantum well structure.

[0067] Each of the first, second and third lower contact electrodes 25p, 35p, 45p may include a transparent conductive material that transmits light. For example, each of the lower contact electrodes 25p, 35p, 45p may include, but is not limited to, a transparent conductive oxide (TCO), such as SnO, InO2, ZnO, ITO (indium tin oxide), ITZO (indium tin zinc oxide), etc.

[0068] The first adhesive layer 61 is disposed between the first light emitting stack 20 and the second light emitting stack 30, the second adhesive layer 63 is disposed between the second light emitting stack 30 and the third light emitting stack 40, and the third adhesive layer 65 is disposed between the substrate 11 and the third light emitting stack 40.

[0069] The first adhesive layer 61 may include a non-conductive material that transmits light. For example, the first adhesive layer 61 may include an optically clear adhesive (OCA), which may include, but is not limited to, epoxy, polyimide, SU8, spin-on-glass (SOG), and benzocyclobutene (BCB).

[0070] In this embodiment, the second adhesive layer 63 contains a conductive material. The second adhesive layer 63 may be commonly and electrically connected to the first conductive type semiconductor layer 31 of the second light emitting stack 30 and the first conductive type semiconductor layer 41 of the third light emitting stack 40. The second adhesive layer 63 may be, for example, a bonding layer of each conductive oxide layer 31n, 41n such as ITO. By forming the second adhesive layer 63 with a conductive material layer, the first conductive type semiconductor layer 31 and the first conductive type semiconductor layer 41 can be electrically connected, and as a result, the manufacturing process of the light emitting element 100 can be simplified.

[0071] The third adhesive layer 65 may bond the substrate 11 and the third light emitting stack 40 and may be removed together with the substrate 11 when the substrate 11 is removed. In this case, the third adhesive layer 65 may be formed of, for example, an adhesive material that reacts to a laser, and as a result, the substrate 11 can be easily removed from each of the light emitting stacks 20, 30, 40 using the laser.

[0072] On the other hand, according to the illustrated embodiment, the first insulating layer 81 and the second insulating layer 83 are disposed on at least a part of each side surface of the first, second, and third light emitting stacks 20, 30, 40. At least one of the first and second insulating layers 81, 83 may contain various organic or inorganic insulating materials, for example, polyimide, SiO2, SiNx, Al2O3, etc. For example, at least one of the first and second insulating layers 81, 83 may contain a distributed Bragg reflector (DBR). As another example, at least one of the first and second insulating layers 81, 83 may contain a black organic polymer. In some embodiments, an electrically floating metal reflective layer is disposed on the first and second insulating layers 81, 83, and the light emitted from each of the light emitting stacks 20, 30, 40 can be reflected toward the third lower contact electrode 45p side. In some embodiments, at least one of the first and second insulating layers 81, 83 may have a single layer structure, or may have a multilayer structure formed of two or more insulating layers having different refractive indexes from each other.

[0073] The first conductive type semiconductor layers 21, 31, 41 of each light emitting stack may be n-type semiconductor layers, and the second conductive type semiconductor layers 25, 35, 45 may be p-type semiconductor layers. The first, second, and third lower contact electrodes 25p, 35p, 45p respectively connected to the p-type semiconductor layers (i.e., the second conductive type semiconductor layers 25, 35, 45) of each light emitting stack may be electrically connected to the first to third connection electrodes 20ce, 30ce, 40ce respectively. On the other hand, the n-type semiconductor layers (i.e., the first conductive type semiconductor layers 21, 31, 41) of each light emitting stack may be commonly and electrically connected to the fourth connection electrode 50ce. Thus, the light emitting element 100 may have a common n-type light emitting stack structure in which the n-type semiconductor layers 21, 31, 41 of the first, second, and third light emitting stacks 20, 30, 40 are commonly connected, and may be driven independently of each other. Since it has a common n-type light emitting stack structure, the sources of the voltages applied to the first, second, and third light emitting stacks 20, 30, 40 can be made different from each other.

[0074] The light emitting element 100 according to the illustrated embodiment has a common n-type structure, but the present disclosure is not limited thereto. For example, in some exemplary embodiments, the first conductive type semiconductor layers 21, 31, 41 of each light emitting stack may be p-type semiconductor layers, and the second conductive type semiconductor layers 25, 35, 45 of each light emitting stack may be n-type semiconductor layers, and as a result, a common p-type light emitting stack structure can be formed. Also, in some embodiments, the stacking sequence of each light emitting stack is not limited to that shown in the drawings and can be variously deformed. Hereinafter, the light emitting element 100 according to an embodiment of the present disclosure will be described with reference to the common n-type light emitting stack structure.

[0075] According to the illustrated embodiment, the light-emitting element 100 includes a first pad 20pd, a second pad 30pd, a third pad 40pd, and a fourth pad 50pd. The first pad 20pd is electrically connected to a first lower contact electrode 25p through a first contact hole 20CH defined by a first insulating layer 81. The first connection electrode 20ce is electrically connected to the first pad 20pd through a first through hole 20ct defined by a second insulating layer 83. The second pad 30pd is electrically connected to a second lower contact electrode 35p through a second contact hole 30CH defined by the first insulating layer 81. The second connection electrode 30ce is electrically connected to the second pad 30pd through a second through hole 30ct defined by the second insulating layer 83.

[0076] The third pad 40pd is electrically connected to a third lower contact electrode 45p through a third contact hole 40CH defined by the first insulating layer 81. The third connection electrode 40ce is electrically connected to the third pad 40pd through a third through hole 40ct defined by the second insulating layer 83.

[0077] The fourth pad 50pd is electrically connected to the first-conductivity-type semiconductor layers 21, 31, 41 of the first, second, and third light-emitting stacks 20, 30, 40 through a first sub-contact hole 50CHa and a second sub-contact hole 50CHb. The first sub-contact hole 50CHa can expose the first upper contact electrode 21n, and the fourth pad 50pd may be connected to the first upper contact electrode 21n through the first sub-contact hole 50CHa. Also, the second sub-contact hole 50CHb is formed on the second adhesive layer 63 and can expose a part of the second adhesive layer 63, and the fourth pad 50pd may be electrically connected to the second adhesive layer 63 through the second sub-contact hole 50CHb. By forming the second adhesive layer 63 as a conductive layer, the fourth pad 50pd may be commonly and electrically connected to the first-conductivity-type semiconductor layer 31 and the first-conductivity-type semiconductor layer 41 using the second sub-contact hole 50CHb.

[0078] The fourth connection electrode 50ce is electrically connected to the fourth pad 50pd through a fourth through-hole 50ct defined by the second insulating layer 83. As a result, it is commonly and electrically connected to the first conductivity type semiconductor layers 21, 31, and 41 through the fourth pad 50pd.

[0079] In this embodiment, although the connection electrodes 20ce, 30ce, 40ce, and 50ce are illustrated and described as being in direct contact with the pads 20pd, 30pd, 40pd, and 50pd respectively, the connection electrodes 20ce, 30ce, 40ce, and 50ce may not be directly connected to the pads 20pd, 30pd, 40pd, and 50pd, and other connectors may be interposed therebetween.

[0080] The first, second, third, and fourth pads 20pd, 30pd, 40pd, and 50pd are spaced apart from each other and insulated. According to one embodiment, each of the first, second, third, and fourth pads 20pd, 30pd, 40pd, and 50pd can cover at least a part of the side surfaces of the first, second, and third light-emitting stacks 20, 30, and 40. Through this, the heat generated from the first, second, and third light-emitting stacks 20, 30, and 40 can be easily dissipated.

[0081] According to the illustrated embodiment, each of the connection electrodes 20ce, 30ce, 40ce, and 50ce may have a substantially long shape protruding upward from the substrate 11. The connection electrodes 20ce, 30ce, 40ce, and 50ce may include, but are not limited to, metals such as Cu, Ni, Ti, Sb, Zn, Mo, Co, Sn, Ag, or alloys thereof. For example, each of the connection electrodes 20ce, 30ce, 40ce, 50ce may include two or more metals or a plurality of different metal layers to reduce the stress from the long shape of each of the connection electrodes 20ce, 30ce, 40ce, and 50ce. In other embodiments, when the connection electrodes 20ce, 30ce, 40ce, and 50ce include Cu, an additional metal may be deposited or plated to suppress the oxidation of Cu. In some embodiments, when the connection electrodes 20ce, 30ce, 40ce, and 50ce include Cu / Ni / Sn, Cu can prevent Sn from penetrating into the light-emitting stack structure. In some embodiments, the connection electrodes 20ce, 30ce, 40ce, 50ce may include a seed layer for forming a metal layer in the plating process, which will be described later.

[0082] As shown in the drawings, each of the connection electrodes 20ce, 30ce, 40ce, and 50ce may have a substantially flat upper surface, so that an electrical connection between an external line or electrode described later and the light-emitting stack structure can be easily made. According to one embodiment of the present disclosure, the surface area of the light-emitting device 100 is, as is known in the art, about 10,000 μm 2 less than, or in other embodiments about 4,000 μm 2 or 2,500 μm 2When including micro LEDs that are less than, the connecting electrodes 20ce, 30ce, 40ce, 50ce may overlap with a part of at least one of the first, second, and third light emitting stacks 20, 30, 40 as shown in the drawings. More specifically, each of the connecting electrodes 20ce, 30ce, 40ce, and 50ce may overlap with at least one step formed on the side surface of the light emitting stack structure. In this way, since the area of the lower surface of the connecting electrode is larger than the area of the upper surface, a larger contact area can be formed between the connecting electrodes 20ce, 30ce, 40ce, 50ce and the light emitting stack structure. As a result, the connecting electrodes 20ce, 30ce, 40ce, 50ce can be formed more stably on the light emitting stack structure. In such a manner, the structure of the light emitting element 100 can be strengthened with a larger contact area between the connecting electrodes 20ce, 30ce, 40ce, 50ce and the light emitting stack structure. Also, since the connecting electrodes 20ce, 30ce, 40ce, 50ce can overlap with at least one step formed on the side surface of the light emitting stack structure, the heat generated in the light emitting stack structure can be more efficiently dissipated to the outside.

[0083] In an exemplary embodiment, at least one of each of the connecting electrodes 20ce, 30ce, 40ce, and 50ce may overlap with the respective side surfaces of each of the light emitting stacks 20, 30, and 40, and as a result, the light emitting stacks 20, 30, 40 efficiently dissipate the heat generated inside to the outside. Also, when the connecting electrodes 20ce, 30ce, 40ce, 50ce contain a reflective substance such as metal, the connecting electrodes 20ce, 30ce, 40ce, 50ce can reflect the light emitted from at least one of the light emitting stacks 20, 30, 40, and as a result, the light efficiency can be improved.

[0084] Generally, during manufacturing, an array of a plurality of light-emitting elements may be formed on a substrate 11. The substrate 11 is cut along a scribing line to individualize (separate) each light-emitting element, and the light-emitting elements can be transferred to another substrate or tape using various transfer techniques for additional processing of the light-emitting elements such as packaging. In this case, when the light-emitting element includes a connection electrode such as a metal bump or pillar protruding outward from the light-emitting structure, various problems may occur during subsequent processes due to the structure of the light-emitting element that exposes each of the connection electrodes to the outside. For example, during the transfer stage. Also, when the light-emitting element is a micro-LED having a surface area of less than about 10,000 μm 2 less than, about 4,000 μm 2 less than or about 2,500 μm 2 less, handling of the light-emitting element can be further complicated by the small form factor.

[0085] For example, when the connection electrode has a substantially long shape such as a rod, transferring the light-emitting element using a conventional vacuum method may be difficult because the light-emitting element may not have a sufficient suction area due to the protruding structure of the connection electrode. Also, the exposed connection electrode may be directly affected by various stresses during subsequent processes such as when the connection electrode contacts a manufacturing apparatus, which can damage the structure of the light-emitting element. As another example, when the light-emitting element is transferred by attaching an adhesive tape on the upper surface (e.g., the surface opposite to the substrate) of the light-emitting element, the contact area between the light-emitting element and the adhesive tape can be limited to the upper surface of the connection electrode. In this case, contrary to when the adhesive tape adheres to the lower surface of the light-emitting element (e.g., the substrate), the adhesive force of the light-emitting element to the adhesive tape may be weakened, and the light-emitting element may be undesirably separated from the adhesive tape during transfer. As another example, when transferring the light-emitting element using a conventional pick-and-place method, the ejection pin may directly contact a part of the light-emitting element disposed between the connection pins, damaging the upper structure of the light-emitting structure. In particular, the ejection pin may hit the center of the light-emitting element, causing physical damage to the upper light-emitting stack of the light-emitting element.

[0086] According to an embodiment of the present disclosure, the protective layer 90 may be formed on the light-emitting stack structure. More specifically, as shown in FIG. 1A, the protective layer 90 is formed between the connection electrodes 20ce, 30ce, 40ce, 50ce and can cover at least the side surfaces of the light-emitting stack structure. According to the illustrated embodiment, the protective layer 90 can expose the side surfaces of the substrate 11, the first and second insulating layers 81, 83, and the third light-emitting stack 40. The protective layer 90 may be formed substantially flush with the upper surfaces of the connection electrodes 20ce, 30ce, 40ce, and 50ce and may include an epoxy molding compound (EMC). This can be formed in various hues such as black, white, or transparent, but the present disclosure is not limited thereto. For example, in some embodiments, the protective layer 90 may include polyimide (PID), and in this case, the PID may be provided as a dry film that is not liquid type in order to increase flatness when applied to the light-emitting stack structure. In some embodiments, the protective layer 90 may include a photosensitive substance. In such a manner, the protective layer 90 not only protects the light-emitting structure from external impacts that may be applied during subsequent processes, but also provides a sufficient contact area to the light-emitting element 100 to facilitate handling during subsequent transfer steps. Further, the protective layer 90 can prevent light leakage to the side surfaces of the light-emitting element 100 and prevent or at least suppress the interference of light emitted from adjacent light-emitting elements 100.

[0087] FIG. 2 is a schematic cross-sectional view of a light-emitting stack structure according to an embodiment of the present disclosure. Since the light-emitting stack structure according to the illustrated embodiment is substantially the same as that included in the above-described light-emitting element 100, for the sake of avoiding duplication, the description of the configuration for forming a substantially identical light-emitting stack structure is omitted. Also, although the first upper contact electrode 21n is not shown, finally, the first upper contact electrode 21n may be provided on the first conductive type semiconductor layer 21.

[0088] Referring to FIG. 2, the first, second, and third lower contact electrodes 25p, 35p, 45p according to an embodiment of the present disclosure are each individual lines SR 、S G 、S B may be connected to. The first-conductive-type semiconductor layers 21, 31, 41 of the first, second, and third light-emitting stacks 20, 30, 40 may be connected to a common line Sc. The common line Sc may be connected to the first-conductive-type semiconductor layer 21 of the first light-emitting stack 20 via the first upper contact electrode 21n. Also, the common line Sc may be connected to the second adhesive layer 63 and commonly and electrically connected to the first-conductive-type semiconductor layers 31, 41.

[0089] One embodiment of the present disclosure can apply different voltages to the first to third light-emitting stacks 20, 30, 40 by adopting an n-common structure. For example, the first light-emitting stack 20 that emits red light can be applied with a relatively lower voltage compared to the second and third light-emitting stacks 30, 40 that emit blue light and green light. Therefore, a voltage source suitable for each light-emitting stack can be used individually, and power loss can be reduced. In the illustrated exemplary embodiment, by using the individual lines S R 、S G 、S B and the common line Sc, the first, second, and third light-emitting stacks 20, 30, and 40 can be individually controlled to selectively emit light.

[0090] The light-emitting stack structure according to one embodiment of the present disclosure can display light of various hues depending on the operating states of the respective light-emitting stacks 20, 30, 40, while a conventional light-emitting element can display various hues by a combination of a large number of light-emitting cells that emit light of a single hue. More specifically, a conventional light-emitting element generally includes light-emitting cells that emit light of different colors, for example, red, green, and blue, spaced apart from each other along a two-dimensional plane in order to implement a full-color display. In this way, a relatively large area can be occupied by conventional light-emitting cells. However, the light-emitting stack structure according to one embodiment of the present disclosure can emit light of different hues by stacking a plurality of light-emitting stacks 20, 30, 40, providing a high level of integration through an area smaller than that of a conventional light-emitting device, and implementing full color.

[0091] Also, when each light-emitting element 100 is mounted on another substrate for manufacturing a display device, for example, the number of elements to be mounted can be significantly reduced compared to conventional light-emitting elements. Thus, especially when hundreds of thousands or millions of pixels are formed in one display device, the manufacturing of the display device using the light-emitting element 100 can be substantially simplified.

[0092] According to an exemplary embodiment, the light-emitting stack structure may further include various additional components to improve the purity and efficiency of the light emitted therefrom. For example, in some exemplary embodiments, a wavelength-pass filter may be disposed between each light-emitting stack. In some embodiments, in order to balance the brightness of light between each light-emitting stack, uneven portions may be formed on the light-emitting surface of at least one light-emitting stack. For example, in order to approximate the photometric mixing ratio of RGB to 3:6:1, it is necessary to increase the photometric intensity of green light, and for this purpose, unevenness may be formed on the second conductivity type semiconductor layer 45.

[0093] Hereinafter, a method of forming the light-emitting element 100 according to an embodiment of the present disclosure will be described with reference to the drawings.

[0094] FIGS. 3A, 4A, 5A, 6A, 7A, and 8A are plan views showing the process of manufacturing the light-emitting element of FIG. 1A according to an exemplary embodiment. FIGS. 3B, 4B, 5B, 6B, 7B, and 8B are cross-sectional views taken along line A-A' of the corresponding plan views shown in FIGS. 3A, 4A, 5A, 6A, 7A, and 8A according to an exemplary embodiment. FIGS. 3C, 4C, 5C, 6C, 7C, and 8C are cross-sectional views taken along line B-B' of the corresponding plan views shown in FIGS. 3A, 4A, 5A, 6A, 7A, and 8A according to an exemplary embodiment.

[0095] Referring again to FIG. 2, the first conductivity type semiconductor layer 41, the third active layer 43, and the second conductivity type semiconductor layer 45 of the third light emitting stack 40 can be sequentially grown on a growth substrate (not shown) by, for example, a metal organic chemical vapor deposition (MOCVD) method or a molecular beam epitaxy (MBE) method. The third lower contact electrode 45p may be formed on the second conductivity type semiconductor layer 45 by, for example, a physical vapor deposition method or a chemical vapor deposition method, and may include a transparent conductive oxide (TCO) such as SnO, InO2, ZnO, ITO, or ITZO. When the third light emitting stack 40 according to an embodiment of the present disclosure emits green light, the growth substrate includes Al2O3 (e.g., a sapphire substrate), and the third lower contact electrode 45p may include a transparent conductive oxide (TCO) such as tin oxide.

[0096] Subsequently, the substrate 11 may be attached on the third light emitting stack 40 with an adhesive layer 65 interposed therebetween, and the growth substrate may be removed from the third light emitting stack 40 using laser lift-off or the like. When the growth substrate is removed, the first conductivity type semiconductor layer 41 is exposed, and a transparent conductive oxide layer 41n such as ITO may be formed on the exposed first conductivity type semiconductor layer 41.

[0097] The second light emitting stack 30 is also formed through a process similar to that of the third light emitting stack 40, and a transparent conductive oxide layer 31n such as ITO may be formed on the first conductivity type semiconductor layer 31 from which the growth substrate has been removed.

[0098] On the other hand, the transparent conductive oxide layer 41n on the third light emitting stack 40 and the transparent conductive oxide layer 31n on the second light emitting stack 30 are joined to each other to form a joining layer 63, and the temporary substrate on the second light emitting stack 30 may be removed.

[0099] On the one hand, the first light-emitting stack 20 can be formed in a similar manner by sequentially growing a first-conductivity-type semiconductor layer, an active layer, and a second-conductivity-type semiconductor layer on a growth substrate. The lower contact electrodes including a transparent conductive oxide (TCO) may be respectively formed on the second-conductivity-type semiconductor layer 25 by, for example, physical vapor deposition or chemical vapor deposition. Then, the first light-emitting stack 20 may be coupled to the second light-emitting stack 30 via the first adhesive layer 61, and the growth substrate may be removed by chemical processes, mechanical processes, or the like.

[0100] In this embodiment, first, the coupling of the second light-emitting stack 30 and the third light-emitting stack 40 will be described, and subsequently, the coupling of the first light-emitting stack 20 to the second light-emitting stack 30, but these orders may be changed. For example, first, the first light-emitting stack 20 and the second light-emitting stack 30 may be coupled, and subsequently, the third light-emitting stack 40 may be coupled to the second light-emitting stack 30.

[0101] Subsequently, referring to FIGS. 3A, 3B, and 3C, various portions of the first, second, and third light-emitting stacks 20, 30, 40 are patterned through an etching process or the like to expose portions of the first-conductivity-type semiconductor layer 21, the first lower contact electrode 25p, the second lower contact electrode 35p, the third lower contact electrode 45p, and the second adhesive layer 63. Instead of the second adhesive layer 63, portions of the first-conductivity-type semiconductor layer 31 or the first-conductivity-type semiconductor layer 41 may be exposed. According to the illustrated embodiment, the first light-emitting stack 20 has the smallest area among the light-emitting stacks 20, 30, 40. On the other hand, the third light-emitting stack 40 can have the largest area among the light-emitting stacks 20, 30, 40, and as a result, the luminous intensity of the third light-emitting stack 40 can be relatively increased. However, the concept of the present disclosure is not particularly limited to the relative sizes of the light-emitting stacks 20, 30, and 40.

[0102] Referring to FIGS. 4A, 4B, and 4C, a part of the upper surface of the first-conductivity-type semiconductor layer 21 of the first light-emitting stack 20 may be patterned through wet etching to form the first upper contact electrode 21n. As described above, the first upper contact electrode 21n is formed with a thickness of about 100 nm in the recessed region of the first-conductivity-type semiconductor layer 21, and for example, the ohmic contact between them can be improved.

[0103] Referring to FIGS. 5A, 5B, and 5C, the first insulating layer 81 may be formed to cover the light-emitting stacks 20, 30, 40, and a part of the first insulating layer 81 may be removed to form the first, second, third, and fourth contact holes 20CH, 30CH, 40CH, and 50CH. The first contact hole 20CH is defined on the first lower contact electrode 25p and exposes a part of the first lower contact electrode 25p. The second contact hole 30CH is defined on the second lower contact electrode 35p and can expose a part of the second lower contact electrode 35p. The third contact hole 40CH is defined on the third lower contact electrode 45p and can expose a part of the third lower contact electrode 45p.

[0104] The fourth contact hole 50CH provides a path for allowing electrical connection to the first-conductivity-type semiconductor layers 21, 31, 41 of the first to third light-emitting stacks 20, 30, 40. The fourth contact hole 50CH may include a first sub-contact hole 50CHa and a second sub-contact hole 50CHb. The first sub-contact hole 50CHa is defined on the first-conductivity-type semiconductor layer 21 and can expose a part of the first upper contact electrode 21n, and the second sub-contact hole 50CHb is defined on the second adhesive layer 63 and can expose a part of the second adhesive layer 63.

[0105] Referring to FIGS. 6A, 6B, and 6C, the first, second, third, and fourth pads 20pd, 30pd, 40pd, and 50pd are formed on a first insulating layer 81 formed to have first, second, third, and fourth contact holes 20CH, 30CH, 40CH, and 50CH. The first, second, third, and fourth pads 20pd, 30pd, 40pd, and 50pd can be formed, for example, by forming a conductive layer substantially over the entire surface of the substrate 11 and patterning the conductive layer using a photolithography process.

[0106] The first pad 20pd is formed to overlap with a region where the first contact hole 20CH is formed and may be connected to the first lower contact electrode 25p through the first contact hole 20CH. The second pad 30pd is formed to overlap with a region where the second contact hole 30CH is formed and may be connected to the second lower contact electrode 35p through the second contact hole 30CH. The third pad 40pd is formed to overlap with a region where the third contact hole 40CH is formed and may be connected to the third lower contact electrode 45p through the third contact hole 40CH. The fourth pad 50pd is formed to overlap with a region where the fourth contact hole 50CH is formed, particularly a region where the first and second sub-contact holes 50CHa, 50CHb are formed, and may be electrically connected to the first conductivity type semiconductor layers 21, 31, 41 of the first to third light emitting stacks 20, 30, 40.

[0107] Referring to FIGS. 7A, 7B, and 7C, the second insulating layer 83 may be formed on the first insulating layer 81. The second insulating layer 83 may include silicon oxide and / or silicon nitride. However, the present disclosure is not limited thereto, and in some embodiments, the first and second insulating layers 81, 83 may include an inorganic substance. Subsequently, the second insulating layer 83 is patterned, and first, second, third, and fourth through holes 20ct, 30ct, 40ct, and 50ct may be formed to expose the first to fourth pads 20pd, 30pd, 40pd, 50pd.

[0108] The first through hole 20ct formed on the first pad 20pd exposes a part of the first pad 20pd. The second through hole 30ct formed on the second pad 30pd exposes a part of the second pad 30pd. The third through hole 40ct formed on the third pad 40pd exposes a part of the third pad 40pd. The fourth through hole 50ct formed on the fourth pad 50pd exposes a part of the fourth pad 50pd. In the illustrated exemplary embodiment, the first, second, third, and fourth through holes 20ct, 30ct, 40ct, and 50ct may be respectively defined within the regions where the first, second, third, and fourth pads 20pd, 30pd, 40pd, and 50pd are formed.

[0109] Referring to FIGS. 8A, 8B, and 8C, first, second, third, and fourth connection electrodes 20ce, 30ce, 40ce, 50ce are formed on the second insulating layer 83 in which the first, second, third, and fourth through holes 20ct, 30ct, 40ct, 50ct are formed. The first connection electrode 20ce may be formed so as to overlap with the region where the first through hole 20ct is formed and may be connected to the first pad 20pd through the first through hole 20ct. The second connection electrode 30ce may be formed so as to overlap with the region where the second through hole 30ct is formed and may be connected to the second pad 30pd through the second through hole 30ct. The third connection electrode 40ce may be formed so as to overlap with the region where the third through hole 40ct is formed and may be connected to the third pad 40pd through the third through hole 40ct. The fourth connection electrode 50ce may be formed so as to overlap with the region where the fourth through hole 50ct is formed and may be connected to the fourth pad 50pd through the fourth through hole 50ct.

[0110] The first, second, third, and fourth connection electrodes 20ce, 30ce, 40ce, 50ce may be formed on the light emitting stack structure separately from each other. The first, second, third, and fourth connection electrodes 20ce, 30ce, 40ce, 50ce are electrically connected to the first, second, third, and fourth pads 20pd, 30pd, 40pd, 50pd respectively, and can transmit an external signal to each of the light emitting stacks 20, 30, 40.

[0111] The method of forming the first, second, third, and fourth connecting electrodes 20ce, 30ce, 40ce, and 50ce is not particularly limited. For example, according to an embodiment of the present disclosure, a seed layer may be deposited as a conductive surface on the light-emitting stack structure, and a photoresist pattern may be formed such that the seed layer is exposed at the position where the connecting electrode is formed. According to one embodiment, the seed layer may be deposited with a thickness of about 1000 Å, but is not limited thereto. Subsequently, the seed layer may be plated with a metal such as Cu, Ni, Ti, Sb, Zn, Mo, Co, Sn, Ta, Ag, or an alloy thereof, and the photoresist pattern and the seed layer remaining between the respective connecting electrodes may be removed. In some exemplary embodiments, an additional metal may be deposited or plated on the plated metal (e.g., each connecting electrode) by electroless nickel immersion gold (ENIG) or the like to prevent or at least suppress oxidation of the plated metal. In some embodiments, the seed layer may remain on each connecting electrode.

[0112] According to the illustrated exemplary embodiment, each of the connecting electrodes 20ce, 30ce, 40ce, and 50ce may have a substantially long shape in a direction away from the substrate 11. In other exemplary embodiments, the connecting electrodes 20ce, 30ce, 40ce may include two or more metals or a plurality of different metal layers to reduce stress from the long shape of the connecting electrodes 20ce, 30ce, 40ce, 50ce. However, the present disclosure is not limited to the specific shape of the connecting electrodes 20ce, 30ce, 40ce, 50ce, and in some embodiments, the connecting electrodes can have various shapes.

[0113] As shown in the drawings, each of the connecting electrodes 20ce, 30ce, 40ce, and 50ce may have a substantially flat upper surface to facilitate electrical connection between the light emitting stack structure and an external line or electrode. Each of the connecting electrodes 20ce, 30ce, 40ce, and 50ce may overlap with at least one step formed on a side surface of the light emitting stack structure. In such a manner, the lower surface of the connecting electrode may have a greater width than the upper surface, providing a greater contact area between the connecting electrodes 20ce, 30ce, 40ce, and 50ce and the light emitting stack structure, and having a more stable structure in which the light emitting element 100 can withstand various subsequent processes together with the protective layer 90. In this case, the length of one side surface of the connecting electrodes 20ce, 30ce, 40ce, and 50ce disposed closer to the outside and the length of the other side surface disposed closer to the center of the light emitting element 100 may be different from each other. For example, the difference in length between two opposing surfaces of the connecting electrode may be 3 μm to 16 μm, but is not limited thereto.

[0114] And a protective layer 90 is disposed between the connecting electrodes 20ce, 30ce, 40ce, and 50ce. The protective layer 90 may be formed substantially flush with the upper surfaces of the connecting electrodes 20ce, 30ce, 40ce, and 50ce by a polishing process or the like. According to one embodiment, the protective layer 90 may include a black epoxy molding compound (EMC), but is not limited thereto. For example, in some embodiments, the protective layer 90 may include a photosensitive polyimide dry film (PID). In such a manner, the protective layer 90 can not only protect the light emitting structure from external shocks applied during subsequent processes, but also provide a sufficient contact area to the light emitting element 100 to facilitate handling during subsequent transfer steps. Further, the protective layer 90 can prevent light leakage to the side surfaces of the light emitting element 100 and prevent or at least suppress interference of light emitted from adjacent light emitting elements 100.

[0115] A plurality of light-emitting elements 100 are formed on a single substrate 11, and these light-emitting elements 100 may be divided into individual light-emitting elements 100 through a singulation process. In one embodiment, after a protective layer 90 is formed on the substrate 11, the individual light-emitting elements 100 can be manufactured by dividing the substrate 11 together with the protective layer 90 using laser scribing and breaking techniques. In other embodiments, after the protective layer 90 is formed, the substrate 11 and the third adhesive layer 65 can be separated, and the individual light-emitting elements 100 can also be manufactured by dividing the protective layer 90.

[0116] The plurality of light-emitting elements 100 may adhere to a tape or the like before being divided. After being divided into individual light-emitting elements, the tape can be expanded, and the light-emitting elements 100 can be spatially separated from each other.

[0117] FIGS. 9A and 9B are schematic cross-sectional views and plan views for explaining a light-emitting package according to an exemplary embodiment.

[0118] According to an embodiment of the present disclosure, the singulated light-emitting elements 100 may first be transferred and arranged on a carrier substrate (not shown). In this case, if the light-emitting element 100 includes a connection electrode that protrudes outward from the light-emitting stack structure, as described above, various problems may occur in subsequent processes, particularly in the transfer process, due to the non-uniform structure. Also, when the light-emitting element includes a micro-LED having a surface area of less than about 10,000 μm 2 less than, less than about 4,000 μm 2 less than or less than about 2,500 μm 2 less than, the handling of the light-emitting element may become even more difficult due to the small form factor. However, the provision of the light-emitting element 100 according to an exemplary embodiment in which a protective layer 90 is disposed between the connection electrodes 20ce, 30ce, 40ce, 50ce not only facilitates the handling of the light-emitting element 100 during subsequent processes such as transfer and packaging, but also protects the light-emitting structure from external shocks and prevents light interference between adjacent light-emitting elements 100.

[0119] Each light-emitting element 100 may be attached onto a carrier substrate with an adhesive layer interposed therebetween. The carrier substrate is not particularly limited as long as it can stably mount the light-emitting element 100.

[0120] The light-emitting element 100 attached onto the carrier substrate may be mounted on the circuit board 11p. According to one embodiment, the circuit board 11p may include an upper circuit electrode 11pa, a lower circuit electrode 11pc, and an intermediate circuit electrode 11pb that are electrically connected to each other. Each upper circuit electrode 11pa may correspond to each of the first, second, third, and fourth connection electrodes 20ce, 30ce, 40ce, and 50ce, respectively. In an exemplary embodiment, each upper circuit electrode 11pa is surface-treated by ENIG and partially melted at a high temperature, so that electrical connection to each connection electrode of the light-emitting element 100 can be easily achieved.

[0121] According to the illustrated embodiment, the light-emitting elements 100 can be spaced apart from each other on the carrier substrate at a desired pitch, preferably in consideration of the pitch P (see FIG. 9B) of the upper circuit electrodes of the circuit board 11p on which the light-emitting elements 100 are mounted in a final target device such as a display device.

[0122] According to an embodiment of the present disclosure, the first, second, third, and fourth connection electrodes 20ce, 30ce, 40ce, and 50ce of the light-emitting element 100 may be bonded to the upper circuit electrode 11pa of the circuit board 11p, for example, by anisotropic conductive film (ACF) bonding. When the light-emitting element 100 is bonded to the circuit board through ACF bonding that can be performed at a lower temperature than other bonding methods, it is possible to prevent the light-emitting element 100 from being exposed to high temperatures during bonding. However, the present disclosure is not limited to a specific bonding method. For example, in some exemplary embodiments, each light-emitting element 100 may be bonded to the circuit board 11p using anisotropic conductive paste (ACP), solder, ball grid array (BGA), or microbumps including at least one of Cu and Sn. In this case, since the upper surfaces of the connection electrodes 20ce, 30ce, 40ce, and 50ce and the protective layer 90 are substantially aligned with each other by a polishing process or the like, the adhesion of the light-emitting element 100 to the anisotropic conductive film increases, and a more stable structure can be formed when bonded to the circuit board 11p.

[0123] Subsequently, a molding layer 91 is formed between the light-emitting elements 100. According to an embodiment, the molding layer 91 can block light by reflecting or absorbing the light emitted from the light-emitting element 100. In particular, the molding layer 91 may be arranged along the upper surface of the light-emitting element 100, that is, the light-emitting surface. Thereby, the emission angle of the light emitted from the first to third light-emitting stacks 20, 30, and 40 can be narrowed. For example, the molding layer 91 may cover the side surface of the substrate 11 and be arranged along the upper surface of the substrate 11. Therefore, the molding layer 91 can prevent light from being emitted to the side surface of the substrate 11 and narrow the emission angle. Furthermore, since the light-emitting surface is limited to the upper surface of the substrate 11, the emission angles of the light of the first to third light-emitting stacks 20, 30, and 40 become substantially the same. In addition, the molding layer 91, together with the protective layer 90 formed on the light-emitting element 100, provides additional protection to the light-emitting package by strengthening its structure.

[0124] In an exemplary embodiment, the molding layer 91 may include an organic or inorganic polymer. In some embodiments, the molding layer 91 may further include a filler such as silica or alumina. In an exemplary embodiment, the molding layer 91 may include the same material as the protective layer 90. The molding layer 91 can be formed through various methods known in the art, such as lamination, plating, and / or printing methods. For example, the molding layer 91 can be formed by a vacuum lamination process in which an organic polymer sheet is disposed on the light-emitting element 100 and high temperature and high pressure are applied in a vacuum, and the light uniformity can be improved by providing a substantially flat upper surface of the light-emitting package. The molding layer 91 may be partially removed through a grinding process or a full-surface etching process so that the upper surface of the light-emitting element 100 is exposed.

[0125] In some embodiments, when the substrate 11 is removed from the light-emitting element 100, the molding layer 91 can cover the side surface of the third lower contact electrode 45p and expose the upper surface of the third lower contact electrode 45p.

[0126] In this embodiment, although the upper surface of the molding layer 91 is illustrated and described as being flush with the upper surface of the light-emitting element 100, a part of the molding layer 91 can also cover the upper surface of the light-emitting element 100. Thereby, it is possible to block the reflection of the light flowing in from the outside by the light-emitting element 100.

[0127] On one hand, the light-emitting element 100 disposed on the circuit board 11p can be formed as a light-emitting package 110 by being cut into a desired configuration. FIG. 9B shows four light-emitting elements 100 (2x2) disposed on the circuit board 11p. However, the present disclosure is not limited to a specific number of light-emitting elements formed in the light-emitting package 110. For example, in some embodiments, the light-emitting package 110 may include one or more light-emitting elements 100 formed on the circuit board 11p. Further, the present disclosure is not limited to a specific arrangement of one or more light-emitting elements 100 within the light-emitting package 110. For example, one or more light-emitting elements 100 within the light-emitting package 110 may be in an n×m arrangement, where n and m are positive integers. According to one embodiment, the circuit board 11p may include scan lines and data lines for independently driving each of the light-emitting elements 100 included in the light-emitting package 110.

[0128] FIG. 10 is a schematic cross-sectional view for explaining a display device according to an embodiment of the present disclosure.

[0129] Referring to FIG. 10, the display device may include a display substrate 11b and a light-emitting package 110. The light-emitting package 110 may be mounted on the display substrate 11b of a final device such as a display device. The display substrate 11b may include target electrodes 11s respectively corresponding to the lower circuit electrodes 11pc of the light-emitting package 110. The display device according to an embodiment of the present disclosure may include a plurality of pixels, and each light-emitting element 100 may be disposed corresponding to each pixel. More specifically, each light-emitting stack of the light-emitting element 100 according to an embodiment of the present disclosure may correspond to each sub-pixel of one pixel. Since the light-emitting element 100 includes vertically stacked light-emitting stacks 20, 30, and 40, the number of elements transferred to each sub-pixel can be substantially reduced compared to the number of conventional light-emitting elements. Further, since the lengths of the opposing surfaces of each pair of connection electrodes are different from each other, connection electrodes can be stably formed in the light-emitting stack structure, and the internal structure can be strengthened. Further, in some embodiments, the light-emitting element 100 includes a protective layer 90 between each pair of connection electrodes, so that the light-emitting element 100 can be protected from external impacts.

[0130] In this embodiment, the light-emitting package 110 is mounted on the display substrate 11b. However, the process of manufacturing the light-emitting package 110 may be omitted, and the molding layer 91 may also be formed by directly mounting the light-emitting element 100 on the display substrate 11b.

[0131] FIG. 11 is a schematic cross-sectional view for explaining a light-emitting package according to another embodiment of the present disclosure.

[0132] Referring to FIG. 11, the light-emitting package according to this embodiment is substantially similar to the light-emitting package already described with reference to FIGS. 9A and 9B, but is different in that the light-emitting element 200 does not include the substrate 11. The substrate 11 and the third adhesive layer 65 are removed from the light-emitting element 100, and as a result, the third lower contact electrode 45p is exposed. The light-emitting element 200 emits light through the upper surface of the third lower contact electrode 45p, and as a result, the upper surface of the third lower contact electrode 45p becomes the light-emitting surface. The molding layer 91 covers the side surface of the third lower contact electrode 45p and exposes its upper surface.

[0133] FIG. 12 is a schematic cross-sectional view of a light-emitting stack structure according to another embodiment of the present disclosure.

[0134] Referring to FIG. 12, the light-emitting stack structure according to this embodiment is substantially similar to the light-emitting stack structure of FIG. 2, but is different in the positions of the first conductive-type semiconductor layer 21 and the second conductive-type semiconductor layer 25 of the first light-emitting stack 20. That is, in this embodiment, the first conductive-type semiconductor layer 21 is disposed closer to the second light-emitting stack 30 than the second conductive-type semiconductor layer 25. On the other hand, the first upper contact electrode 21n is disposed below the first conductive-type semiconductor layer 21, and the first lower contact electrode 25p is disposed on the second conductive-type semiconductor layer 25.

[0135] Each individual line S R , S B , S Gmay be electrically connected to the first to third lower contact electrodes 25p, 35p, and 45p, respectively, and the common line Sc may be electrically connected to the first upper contact electrode 21n and the second adhesive layer 63. By using the light-emitting stack structure according to this embodiment, a light-emitting element having a common n light-emitting stack structure can be provided.

[0136] FIG. 13 is a schematic cross-sectional view of a light-emitting stack structure according to another embodiment of the present disclosure.

[0137] Referring to FIG. 13, the light-emitting stack structure according to this embodiment is substantially similar to the light-emitting stack structure of FIG. 2, but is different in that the first adhesive layer 61a contains a conductive material. That is, in the embodiment of FIG. 2, the second adhesive layer 63 contains a conductive material and electrically connects the first conductive type semiconductor layers 31 and 41 to each other, while in this embodiment, the first adhesive layer 61a contains a conductive material and electrically connects the first conductive type semiconductor layers 21 and 31 to each other. The first adhesive layer 61a may be, for example, a bonding layer between the first upper contact electrode 21n and the second upper contact electrode 31n, where the first upper contact electrode 21n and the second upper contact electrode 31n may each be formed of a transparent conductive oxide layer such as ITO. On the other hand, the second adhesive layer 63a is formed of an insulating material, and as a result, the third light-emitting stack 40 is insulated from the second light-emitting stack 30 by the second adhesive layer 63a.

[0138] Each individual line S R , S B , S G may be electrically connected to the first to third lower contact electrodes 25p, 35p, and 45p, respectively, and the common line Sc may be electrically connected to the first adhesive layer 61a and the first conductive type semiconductor layer 41. By using the light-emitting stack structure according to this embodiment, a light-emitting element having a common n light-emitting stack structure can be provided.

[0139] FIG. 14 is a schematic cross-sectional view of a light-emitting stack structure according to another embodiment of the present disclosure.

[0140] Referring to FIG. 14, the light-emitting stack structure according to this embodiment is substantially similar to the light-emitting stack structure of FIG. 13, but is different in the positions of the first-conductivity-type semiconductor layer 41 and the second-conductivity-type semiconductor layer 45 of the third light-emitting stack 40. That is, in this embodiment, the second-conductivity-type semiconductor layer 45 is disposed closer to the second light-emitting stack 30 than the first-conductivity-type semiconductor layer 41. On the other hand, the third lower contact electrode 45p is disposed on the second-conductivity-type semiconductor layer 45.

[0141] In this embodiment, the substrate 141 may be a growth substrate for growing the third light-emitting stack 40, and the first-conductivity-type semiconductor layer 41 can be grown on the substrate 141. Therefore, the third adhesive layer 65 described in each of the above embodiments is omitted in this embodiment.

[0142] Each individual line S R 、S B 、S G may be electrically connected to the first to third lower contact electrodes 25p, 35p, 45p, respectively, and the common line Sc may be electrically connected to the first adhesive layer 61a and the first-conductivity-type semiconductor layer 41. By using the light-emitting stack structure according to this embodiment, a light-emitting element of a common n light-emitting stack structure can be provided.

[0143] FIG. 15 is a schematic cross-sectional view of a light-emitting stack structure according to another embodiment of the present disclosure.

[0144] Referring to FIG. 15, the light-emitting stack structure according to this embodiment is substantially similar to the light-emitting stack structure described with reference to FIG. 2, but is different in that the second adhesive layer 63b electrically connects the second-conductivity-type semiconductor layer 35 of the second light-emitting stack 30 and the second-conductivity-type semiconductor layer 45 of the third light-emitting stack 40, and the substrate 141 may be a growth substrate for growing the third light-emitting stack 40.

[0145] In one embodiment, the second adhesive layer 63b may be a bonding layer between the second lower contact electrode 35p and the third lower contact electrode 45p, and the second and third lower contact electrodes 35p and 45p may each be a transparent conductive oxide layer such as ITO.

[0146] In this embodiment, each individual line S R , S B , S G may be electrically connected to the first conductive type semiconductor layers 21, 31, and 41, respectively, and the common line Sc may be electrically connected in common to the first lower contact electrode 25p and the second adhesive layer 63b. By using the light emitting stack structure according to this embodiment, a light emitting element of a common p light emitting stack structure can be provided.

[0147] FIG. 16 is a schematic cross-sectional view of a light emitting stack structure according to another embodiment of the present disclosure.

[0148] Referring to FIG. 16, the light emitting stack structure according to this embodiment is substantially similar to the light emitting stack structure described with reference to FIG. 15, but is different in the positions of the first conductive type semiconductor layer 21 and the second conductive type semiconductor layer 25 of the first light emitting stack 20. That is, in this embodiment, the first conductive type semiconductor layer 21 is disposed closer to the second light emitting stack 30 than the second conductive type semiconductor layer 25. On the other hand, the first upper contact electrode 21n is disposed below the first conductive type semiconductor layer 21, and the first lower contact electrode 25p is disposed on the second conductive type semiconductor layer 25.

[0149] Each individual line S R , S B , S G may be electrically connected to the first conductive type semiconductor layers 21, 31, and 41, respectively, and the common line Sc may be electrically connected in common to the first lower contact electrode 25p and the second adhesive layer 63b. By using the light emitting stack structure according to this embodiment, a light emitting element of a common p light emitting stack structure can be provided.

[0150] FIG. 17 is a schematic cross-sectional view of a light-emitting stack structure according to another embodiment of the present disclosure.

[0151] Referring to FIG. 17, the light-emitting stack structure according to this embodiment is substantially similar to the light-emitting stack structure described with reference to FIG. 13, but is different in that the first adhesive layer 61b electrically connects the second-conductive-type semiconductor layer 25 of the first light-emitting stack 20 and the second-conductive-type semiconductor layer 35 of the second light-emitting stack 30.

[0152] In one embodiment, the first adhesive layer 61b may be a bonding layer of the first lower contact electrode 25p and the second lower contact electrode 35p, and the first and second lower contact electrodes 25p, 35p may each be a transparent conductive oxide layer such as ITO.

[0153] In this embodiment, each individual line S R , S B , S G may be electrically connected to the first-conductive-type semiconductor layers 21, 31, 41, respectively, and the common line Sc may be commonly and electrically connected to the first adhesive layer 61b and the third lower contact electrode 45p. By using the light-emitting stack structure according to this embodiment, a light-emitting element of a common p light-emitting stack structure can be provided.

[0154] FIG. 18 is a schematic cross-sectional view of a light-emitting stack structure according to another embodiment of the present disclosure.

[0155] Referring to FIG. 18, the light-emitting stack structure according to this embodiment is substantially similar to the light-emitting stack structure described with reference to FIG. 17, but is different in the positions of the first-conductive-type semiconductor layer 41 and the second-conductive-type semiconductor layer 45 of the third light-emitting stack 40. That is, in this embodiment, the second-conductive-type semiconductor layer 45 is disposed closer to the second light-emitting stack 30 than the first-conductive-type semiconductor layer 41. On the other hand, the third lower contact electrode 45p is disposed on the second-conductive-type semiconductor layer 45.

[0156] In this embodiment, the substrate 141 may be a growth substrate for growing the third light-emitting stack 40, and the first conductivity type semiconductor layer 41 may be grown on the substrate 141. Accordingly, the third adhesive layer 65 described in each of the above embodiments is omitted in this embodiment.

[0157] Each individual line S R , S B , S G may be electrically connected to the first conductivity type semiconductor layers 21, 31, and 41, respectively, and the common line Sc may be electrically connected to the first adhesive layer 61b and the third lower contact electrode 45p. By using the light-emitting stack structure according to this embodiment, a light-emitting element having a common p light-emitting stack structure can be provided.

[0158] FIG. 19 is a schematic cross-sectional view of a light-emitting stack structure according to another embodiment of the present disclosure.

[0159] Referring to FIG. 19, the light-emitting stack structure according to this embodiment is substantially similar to the light-emitting stack structure described with reference to FIG. 2, but differs in that the second adhesive layer 63a contains a non-conductive material. The second adhesive layer 63a can transmit light. For example, the second adhesive layer 63a may include an optically transparent adhesive (OCA), which may include, but is not limited to, epoxy, polyimide, SU8, spin-on-glass (SOG), and benzocyclobutene (BCB).

[0160] Since the second adhesive layer 63a contains a non-conductive material, the first conductivity type semiconductor layer 31 of the second light-emitting stack 30 and the first conductivity type semiconductor layer 41 of the third light-emitting stack 40 are insulated by the second adhesive layer 63a.

[0161] FIG. 20A is a schematic plan view for explaining a light-emitting element according to another embodiment of the present disclosure, FIG. 20B is a schematic cross-sectional view taken along the line A-A' of FIG. 20A, and FIG. 20C is a schematic cross-sectional view taken along the line B-B' of FIG. 20A. Here, the light-emitting element may be formed using the light-emitting stack structure of FIG. 19, and the manufacturing process is omitted.

[0162] Referring to FIGS. 20A, 20B, and 20C, the light-emitting device according to this embodiment is substantially similar to the light-emitting device 100 already described with reference to FIGS. 1A to 1D, but differs in that the second adhesive layer 63a contains a non-conductive material.

[0163] For example, the second sub-contact hole 50CHb of the first insulating layer 81 does not expose a part of the second adhesive layer 63a, but exposes both a part of the first conductivity type semiconductor layer 31 and a part of the first conductivity type semiconductor layer 41. One sub-contact hole 50CHb can be used to simultaneously expose the first conductivity type semiconductor layers 31 and 41, and the process margin can be increased.

[0164] On the other hand, the fourth pad 50pd can be electrically connected to the first conductivity type semiconductor layers 31 and 41 through the second sub-contact hole 50CHb, and can be electrically connected to the first upper contact electrode 21n through the first sub-contact hole 50CHa. The fourth connection electrode 50ce is connected to the fourth pad 50pd exposed through the through hole 50ct of the second insulating layer 83, and as a result, can be commonly and electrically connected to the first conductivity type semiconductor layers 21, 31, and 41 through the fourth pad 50pd. Thereby, a light-emitting device with a common n structure can be provided.

[0165] In this embodiment, the substrate 11 and the third adhesive layer 65 of FIG. 19 may be finally removed from the light-emitting device. In other embodiments, the substrate 11 and the third adhesive layer 65 may remain in the light-emitting device.

[0166] Although specific exemplary embodiments and implementations have been described herein, other embodiments and modifications will be apparent from this description. Therefore, the present disclosure is not limited to such embodiments, but includes a broader scope of the appended claims and various modifications and equivalent configurations that are apparent and diverse to those skilled in the art.

Description of Reference Numerals

[0167] 11 Substrate 11b Display Substrate 11p circuit board 11pa upper circuit electrode 11pb middle circuit electrode 11pc lower circuit electrode 11s target electrode 20 first light-emitting stack 20ce first connection electrode 20CH first contact hole 20ct first through hole 20pd first pad 21 first conductive type semiconductor layer 21n first upper contact electrode 23 active layer 25 second conductive type semiconductor layer 25p first lower contact electrode 30 second light-emitting stack 30ce second connection electrode 30CH second contact hole 30ct second through hole 30pd second pad 31 first conductive type semiconductor layer 31n second upper contact electrode 33 active layer 35 second conductive type semiconductor layer 35p second lower contact electrode 40 third light-emitting stack 40ce third connection electrode 40CH third contact hole 40ct third through hole 40pd third pad 41 first conductive type semiconductor layer 41n transparent conductive oxide layer 43 third active layer 45 second conductive type semiconductor layer 45p third lower contact electrode 50ce fourth connection electrode 50CH fourth contact hole 50CHa first sub-contact hole 50CHb second sub-contact hole 50ct fourth through hole 50pd Fourth Pad 61, 61a, 61b First Adhesive Layer 63, 63a, 63b Second Adhesive Layer 65 Third Adhesive Layer 81 First Insulating Layer 83 Second Insulating Layer 90 Protective Layer 91 Molding Layer 100 Light-Emitting Element 110 Light-Emitting Package 141 Substrate 200 Light-Emitting Element

Claims

1. A display substrate; A plurality of light-emitting elements disposed on the display substrate; and A molding layer covering the side surfaces of the light-emitting elements, the molding layer preventing light from being emitted to the side surface of the substrate, and the molding layer restricting the light-emitting surface of the light-emitting elements to the upper surface of the substrate, a display device including the molding layer; The light-emitting elements are A first light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; A second light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; A third light-emitting stack including a first-conductivity-type semiconductor layer and a second-conductivity-type semiconductor layer; A first adhesive layer bonding the first light-emitting stack and the second light-emitting stack; and A second adhesive layer bonding the second light-emitting stack and the third light-emitting stack; including, The second light-emitting stack is disposed between the first light-emitting stack and the third light-emitting stack, One of the first adhesive layer and the second adhesive layer electrically connects the adjacent light-emitting stack, and A substrate is disposed adjacent to the third light-emitting stack, a display device.

2. The first, second, and third light-emitting stacks respectively emit red light, blue light, and green light, the display device according to Claim 1.

3. A first connection electrode electrically connected to the first light-emitting stack; A second connection electrode electrically connected to the second light-emitting stack; A third connection electrode electrically connected to the third light-emitting stack; and A fourth connection electrode commonly and electrically connected to the first, second, and third light-emitting stacks; further including, the display device according to Claim 1.

4. The fourth connection electrode is electrically connected to the adjacent light-emitting stack through one of the first adhesive layer and the second adhesive layer that electrically connects the adjacent light-emitting stack, the display device according to Claim 3.

5. The fourth connection electrode is commonly and electrically connected to the first-conductivity-type semiconductor layers of the first, second, and third light-emitting stacks, The first-conductivity-type semiconductor layer is an n-type semiconductor layer, the display device according to Claim 4.

6. The fourth connection electrode is commonly and electrically connected to the second-conductivity-type semiconductor layers of the first, second, and third light-emitting stacks, The second-conductivity-type semiconductor layer is a p-type semiconductor layer, the display device according to Claim 4.

7. The display device according to claim 3, further comprising a protective layer surrounding at least a part of the first, second, third, and fourth connection electrodes.

8. The protective layer includes an epoxy molding compound or a polyimide film, The display device according to claim 7, wherein an upper surface of the protective layer is substantially flush with upper surfaces of the first, second, third, and fourth connection electrodes.

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