Light-emitting devices and display devices

Abstract

A light-emitting device and a display device, the light-emitting device comprising: a first LED stack; a second LED stack, arranged below the first LED stack; a third LED stack, arranged below the second LED stack; and an electrode pad, electrically connected to the first LED stack, the second LED stack and the third LED stack, the electrode pad comprising: a common electrode pad, electrically connected to the first LED stack, the second LED stack and the third LED stack; and a first electrode pad, a second electrode pad and a third electrode pad, respectively connected to the first LED stack, the second LED stack and the third LED stack, the first LED stack, the second LED stack and the third LED stack are independently drivable, light generated in the first LED stack is emitted to the outside through the second LED stack and the third LED stack, and light generated in the second LED stack is emitted to the outside through the third LED stack.

Description

[0001] This application is a divisional application with application date of December 4, 2018, application number 201880039551.5, and invention name “Light-emitting device with LED stack for display and display device with the same”. Technical Field

[0002] The invention relates to a light emitting device and a display apparatus. Background Art

[0003] Light emitting diodes (LEDs) have been widely used as inorganic light sources in various fields such as display devices, automotive lights, and general lighting. Compared with existing light sources, light emitting diodes have longer life, lower power consumption, and faster response time, and therefore, LEDs are rapidly replacing existing light sources.

[0004] Conventional LEDs have been used mainly as backlight sources in display devices to date. However, recently, LED displays that directly generate images using light emitting diodes have been developed.

[0005] Display devices usually emit various colors by mixing blue light, green light and red light. In order to generate various images, each pixel has blue, green and red sub-pixels. The color of a particular pixel is determined by the colors of the sub-pixels, and the image is generated by the combination of these pixels.

[0006] Because LEDs can emit light of various colors depending on the materials used therein, individual LED chips emitting blue, green, and red light can be arranged on a two-dimensional plane of a display device. However, when one LED chip forms each sub-pixel, the number of LED chips required to form a display device may exceed millions, resulting in excessive time consumption in the installation process.

[0007] In addition, since the sub-pixels are arranged on a two-dimensional plane, one pixel including sub-pixels for blue light, green light, and red light occupies a relatively large area. Therefore, it is necessary to reduce the area of ​​each sub-pixel so that the sub-pixels can be formed in a limited area. However, this will lead to degradation of brightness due to the reduced light-emitting area, and increase the complexity of manufacturing in the process of mounting the LED chip.

[0008] Furthermore, reducing the area of ​​each sub-pixel will also lead to degradation of the light emitting efficiency of the LED due to heat generated in the LED chip.

[0009] The above information disclosed in this Background section is only for understanding the background of the present inventive concept and therefore, the above information may contain information that does not constitute the prior art. Summary of the invention

[0010] Technical issues

[0011] A light emitting diode and a display using the same constructed according to the principles and some exemplary embodiments of the present invention can increase the area of ​​each sub-pixel without increasing the area of ​​a pixel.

[0012] Light emitting diodes and displays using the same, such as micro-LEDs, constructed in accordance with the principles and some exemplary embodiments of the present invention can reduce the amount of time associated with mounting light emitting devices on circuit boards during manufacturing.

[0013] Light emitting diodes and displays using the same, such as micro-LEDs, constructed according to the principles and some exemplary embodiments of the present invention include one or more structures for improving current distribution.

[0014] Light emitting diodes and displays using the same, such as micro-LEDs, constructed according to the principles and some exemplary embodiments of the present invention include structures for improving heat dissipation.

[0015] Light emitting diodes and displays using the same, such as micro-LEDs, constructed according to the principles and some exemplary embodiments of the present invention include a mesh structure for improving light efficiency.

[0016] Additional features of the inventive concept will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concept.

[0017] Solution to the problem

[0018] Provided is a light-emitting device for a display, the light-emitting device comprising: a first LED stack; a second LED stack arranged below the first LED stack; a third LED stack arranged below the second LED stack; and electrode pads electrically connected to the first LED stack, the second LED stack and the third LED stack, the electrode pads comprising: a common electrode pad electrically connected to the first LED stack, the second LED stack and the third LED stack; and a first electrode pad, a second electrode pad and a third electrode pad respectively connected to the first LED stack, the second LED stack and the third LED stack, the first LED stack, the second LED stack and the third LED stack are independently drivable, light generated in the first LED stack is emitted to the outside through the second LED stack and the third LED stack, and light generated in the second LED stack is emitted to the outside through the third LED stack.

[0019] A display device is provided, comprising: a circuit board; and a plurality of light emitting devices arranged on the circuit board, wherein the light emitting devices are the above-mentioned light emitting devices, and electrode pads of the light emitting devices are electrically connected to the circuit board.

[0020] According to an exemplary embodiment, a light-emitting device for a display includes: a first LED sub-unit; a second LED sub-unit, which is arranged below the first LED sub-unit; a third LED sub-unit, which is arranged below the second LED sub-unit; and an electrode pad, which is electrically connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit, wherein the electrode pad includes a common electrode pad which is electrically connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit and a first electrode pad, a second electrode pad and a third electrode pad which are respectively connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit, the first LED sub-unit, the second LED sub-unit and the third LED sub-unit are configured to be driven independently, the light generated in the first LED sub-unit is configured to be emitted to the outside of the light-emitting device through the second LED sub-unit and the third LED sub-unit, and the light generated in the second LED sub-unit is configured to be emitted to the outside of the light-emitting device through the third LED sub-unit.

[0021] The first, second, and third LED sub-units may include first, second, and third LED stacks configured to emit red, green, and blue light, respectively.

[0022] The light emitting device may further include a first reflective electrode disposed between the electrode pad and the first LED sub-unit and in ohmic contact with the first LED sub-unit, wherein the common electrode pad is connected to the first reflective electrode.

[0023] The first reflective electrode may include: an ohmic contact layer in ohmic contact with an upper surface of the first LED sub-unit; and a reflective layer covering at least a portion of the ohmic contact layer.

[0024] The first reflective electrode may be in ohmic contact with the upper surface of the first LED sub-unit in a plurality of regions.

[0025] The light emitting device may further include: a second transparent electrode, which is interposed between the second LED sub-unit and the third LED sub-unit and is in ohmic contact with the lower surface of the second LED sub-unit; and a third transparent electrode, which is in ohmic contact with the upper surface of the third LED sub-unit, wherein the common electrode pad is electrically connected to the second transparent electrode and the third transparent electrode.

[0026] The light emitting device may further include a first metal current distribution layer connected to a lower surface of the second transparent electrode and a third metal current distribution layer connected to an upper surface of the third transparent electrode, wherein the common electrode pad is connected to the first metal current distribution layer and the third metal current distribution layer.

[0027] Each of the first metal current distribution layer and the third metal current distribution layer may have a pad region for connecting to the common electrode pad and a protrusion extending from the pad region.

[0028] The common electrode pad may be connected to an upper surface of the first metal current distribution layer and an upper surface of the third metal current distribution layer.

[0029] The light emitting device may further include a first color filter disposed between the third transparent electrode and the second LED subunit, wherein the third metal current distribution layer is disposed between the first color filter and the second LED subunit to be connected to the third transparent electrode through the first color filter.

[0030] The light emitting device may further include: a second color filter, disposed between the first LED sub-unit and the second LED sub-unit; and a second metal current distribution layer, disposed between the second color filter and the first LED sub-unit to be connected to the second transparent electrode through the second color filter, wherein the second electrode pad is connected to the second metal current distribution layer.

[0031] The second metal current distribution layer may have a pad region for connecting the second electrode pad and a protrusion extension portion extending from the pad region.

[0032] The first LED sub-unit and the third LED sub-unit may each include a first conductive semiconductor layer and a second conductive semiconductor layer arranged on a partial area of ​​the first conductive semiconductor layer, and the first electrode pad and the third electrode pad may be electrically connected to the first conductive semiconductor layer of the first LED sub-unit and the first conductive semiconductor layer of the third LED sub-unit, respectively.

[0033] The light emitting device may further include: a first ohmic electrode, disposed on the first conductive semiconductor layer of the first LED subunit; and a third ohmic electrode, disposed on the first conductive semiconductor layer of the third LED subunit, wherein the first electrode pad is connected to the first ohmic electrode, and the third electrode pad is connected to the third ohmic electrode.

[0034] The light emitting device may further include: a substrate connected to a lower surface of the third LED sub-unit.

[0035] The substrate may be a sapphire substrate or a gallium nitride substrate.

[0036] The light emitting device may further include an upper insulating layer disposed between the first LED sub-unit and the electrode pad, wherein the electrode pad is electrically connected to the first, second and third LED sub-units through the upper insulating layer.

[0037] The upper insulating layer may include at least one of a distributed Bragg reflector, a reflective organic material, and a light blocking material.

[0038] The light emitting device may include a micro-LED having a surface area less than approximately 10,000 square microns, the first LED sub-unit may be configured to emit any one of red light, green light, and blue light, the second LED sub-unit may be configured to emit one of red light, green light, and blue light different from the first LED sub-unit, and the third LED sub-unit may be configured to emit one of red light, green light, and blue light different from the first LED sub-unit and the second LED sub-unit.

[0039] The display device may include a circuit board and a plurality of light emitting devices arranged on the circuit board, at least one of the light emitting devices may include a light emitting device according to an exemplary embodiment, wherein the electrode pad of the light emitting device may be electrically connected to the circuit board, and the light emitting device may further include a substrate coupled to a corresponding third LED subunit, and the substrates may be spaced apart from each other.

[0040] According to an exemplary embodiment, a light-emitting device for a display includes: a first LED sub-unit; a second LED sub-unit, which is arranged on the first LED sub-unit; a third LED sub-unit, which is arranged on the second LED sub-unit; an electrode pad, which is arranged below the first LED sub-unit; and a filler, which is arranged between the electrode pads, wherein the electrode pads include a common electrode pad that is electrically connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit, and a first electrode pad, a second electrode pad and a third electrode pad that are respectively connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit, the first LED sub-unit, the second LED sub-unit and the third LED sub-unit are independently drivable, the light generated in the first LED sub-unit is configured to be emitted to the outside of the light-emitting device through the second LED sub-unit and the third LED sub-unit, and the light generated in the second LED sub-unit is configured to be emitted to the outside through the third LED sub-unit.

[0041] The first LED sub-unit, the second LED sub-unit, and the third LED sub-unit may respectively include a first LED stack configured to emit red light, a second LED stack configured to emit green light, and a third LED stack configured to emit blue light.

[0042] The light emitting device may further include: a first ohmic electrode, which is in ohmic contact with the first conductive semiconductor layer of the first LED sub-unit; and a first reflective electrode, which is arranged between the electrode pad and the first LED sub-unit to be in ohmic contact with the first LED sub-unit, wherein the first electrode pad is electrically connected to the first ohmic electrode, and the common electrode pad is electrically connected to the first reflective electrode below the first reflective electrode.

[0043] The first reflective electrode may include: an ohmic contact layer making ohmic contact with the second conductive semiconductor layer of the first LED sub-unit; and a reflective layer covering at least a portion of the ohmic contact layer.

[0044] The first reflective electrode may be in ohmic contact with an upper surface of the first LED sub-unit in a plurality of regions.

[0045] The light emitting device may further include: a second transparent electrode disposed between the first LED sub-unit and the second LED sub-unit to make ohmic contact with the lower surface of the second LED sub-unit; a third transparent electrode disposed between the second LED sub-unit and the third LED sub-unit to make ohmic contact with the lower surface of the third LED sub-unit; and a common connector electrically connecting the second transparent electrode and the third transparent electrode to the first reflective electrode, wherein the common connector is disposed on the first reflective electrode and electrically connected to the common electrode pad through the first reflective electrode.

[0046] The light emitting device may further include: a second metal current diffusion layer connected to the lower surface of the second transparent electrode; and a third metal current diffusion layer connected to the lower surface of the third transparent electrode, wherein the common connection member is connected to at least one of the second transparent electrode and the second metal current diffusion layer and at least one of the third transparent electrode and the third metal current diffusion layer.

[0047] The second metal current spreading layer and the third metal current spreading layer may each have a pad region for connecting to the common connection and a protrusion extending from the pad region.

[0048] The common connection may be connected to an upper surface of the second metal current spreading layer and an upper surface of the third metal current spreading layer.

[0049] The common connector may include: a first common connector for electrically connecting the second transparent electrode and the first reflective electrode to each other; and a second common connector for electrically connecting the third transparent electrode and the first common connector to each other.

[0050] The light emitting device may further include: a first color filter, arranged between the first LED subunit and the second transparent electrode; and a second color filter, arranged between the second LED subunit and the third transparent electrode, wherein the second metal current diffusion layer is arranged between the first color filter and the first LED subunit to be connected to the second transparent electrode through the first color filter, and the third metal current diffusion layer is arranged between the second color filter and the second LED subunit to be connected to the third transparent electrode through the second color filter.

[0051] The light-emitting device may further include: a second connector for electrically connecting the second LED sub-unit and the second electrode pad to each other; and a third connector for electrically connecting the third LED sub-unit and the third electrode pad to each other, wherein each of the second LED sub-unit and the third LED sub-unit may include a first conductive semiconductor layer and a second conductive semiconductor layer arranged below the first conductive semiconductor layer, the second connector is electrically connected to the first conductive semiconductor layer of the second LED sub-unit, and the third connector is electrically connected to the first conductive semiconductor layer of the third LED sub-unit.

[0052] At least one of the second connector and the third connector may contact the first conductive type semiconductor layer.

[0053] The light emitting device may further include: a second ohmic electrode in ohmic contact with the first conductive semiconductor layer of the second LED subunit; and a third ohmic electrode in ohmic contact with the first conductive semiconductor layer of the third LED subunit, wherein the second connecting member is connected to the second ohmic electrode, and the third connecting member is connected to the third ohmic electrode.

[0054] The second connection member and the third connection member may be connected to an upper surface of the second ohmic electrode and an upper surface of the third ohmic electrode, respectively.

[0055] The third connection member may include: a lower connection member passing through the second LED sub-unit; and an upper connection member passing through the third LED sub-unit and connected to an intermediate connection member, wherein the lower connection member has a pad area for connecting to the upper connection member.

[0056] The light emitting device may further include: an insulating layer covering side surfaces of the first LED sub-unit, the second LED sub-unit, and the third LED sub-unit, wherein the insulating layer may include a distributed Bragg reflector.

[0057] The light-emitting device may further include: a connecting pad, arranged below the first LED sub-unit; and a connector, arranged on the connecting pad and electrically connecting the second LED sub-unit and the third LED sub-unit to the connecting pad, respectively, wherein the second electrode pad and the third electrode pad are respectively connected to the connecting pad below the connecting pad.

[0058] The light emitting device may further include: a connection member for electrically connecting the second LED sub-unit and the third LED sub-unit to the electrode pad, wherein the connection member may include a material different from that of the electrode pad.

[0059] The display apparatus may include a circuit board and a plurality of light emitting devices arranged on the circuit board, at least one of the light emitting devices may include the light emitting device according to an exemplary embodiment, wherein the electrode pad of the light emitting device is electrically connected to the circuit board.

[0060] According to an exemplary embodiment, a light emitting device for a display includes: a first substrate; a first LED sub-unit, which is arranged below the first substrate; a second LED sub-unit, which is arranged below the first LED sub-unit; a third LED sub-unit, which is arranged below the second LED sub-unit; a first transparent electrode, which is interposed between the first LED sub-unit and the second LED sub-unit and is in ohmic contact with the lower surface of the first LED sub-unit; a second transparent electrode, which is interposed between the second LED sub-unit and the third LED sub-unit and is in ohmic contact with the lower surface of the second LED sub-unit; a third transparent electrode, which is interposed between the second transparent electrode and the third LED sub-unit and is in ohmic contact with the upper surface of the third LED sub-unit; at least one current diffusion member, which is connected to at least one of the first LED sub-unit, the second LED sub-unit and the third LED sub-unit; an electrode pad, which is arranged on the first substrate; and a through-hole passage, which is formed through the first substrate to electrically connect the electrode pad to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit, wherein at least one of the through-hole passages is formed through the first substrate, the first LED sub-unit and the second LED sub-unit.

[0061] The first LED sub-unit, the second LED sub-unit, and the third LED sub-unit may respectively include a first LED stack configured to emit red light, a second LED stack configured to emit green light, and a third LED stack configured to emit blue light.

[0062] The light emitting device may further include a distributed Bragg reflector interposed between the first substrate and the first LED subunit.

[0063] The first substrate may include GaAs.

[0064] The light emitting device may further include a second substrate disposed under the third LED sub-unit.

[0065] The second substrate may be a sapphire substrate or a GaN substrate.

[0066] The first LED sub-unit, the second LED sub-unit and the third LED sub-unit may be independently drivable, the light generated from the first LED sub-unit may be configured to be emitted to the outside of the light-emitting device through the second LED sub-unit, the third LED sub-unit and the second substrate, and the light generated from the second LED sub-unit may be configured to be emitted to the outside of the light-emitting device through the third LED sub-unit and the second substrate.

[0067] The electrode pad may include: a common electrode pad, which is electrically connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit; and a first electrode pad, a second electrode pad and a third electrode pad, which are electrically connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit respectively.

[0068] The common electrode pad may be electrically connected to a plurality of through-hole vias.

[0069] The second electrode pad can be electrically connected to the second LED sub-unit via a first through-hole path formed through the first substrate and the first LED sub-unit, and the third electrode pad can be electrically connected to the third LED sub-unit via a second through-hole path formed through the first substrate, the first LED sub-unit and the second LED sub-unit.

[0070] The first electrode pad may be electrically connected to the first substrate.

[0071] The first electrode pad may be electrically connected to the first LED sub-unit through a third through-hole via formed through the first substrate.

[0072] The at least one current spreading member may include: a first current spreading member, connected to the first LED sub-unit; a second current spreading member, connected to the second LED sub-unit; and a third current spreading member, connected to the third LED sub-unit, and the first current spreading member, the second current spreading member and the third current spreading member may be isolated from the first transparent electrode, the second transparent electrode and the third transparent electrode, respectively.

[0073] One of the electrode pads disposed on the first substrate may be electrically connected to the first transparent electrode, the second transparent electrode, and the third transparent electrode through a plurality of through-hole vias.

[0074] One of the electrode pads disposed on the first substrate may be connected to the first substrate.

[0075] The light emitting device may further include: a first color filter disposed between the third transparent electrode and the second transparent electrode; and a second color filter disposed between the second LED subunit and the first transparent electrode.

[0076] The first color filter and the second color filter may include insulating layers having different refractive indices.

[0077] The light emitting device may include an insulating layer disposed between the first substrate and the electrode pad and covering side surfaces of the first LED sub-unit, the second LED sub-unit, and the third LED sub-unit.

[0078] The at least one current spreader may have a body at least partially surrounding one of the through-hole vias and a protrusion extending outwardly from the body.

[0079] The body may have a generally annular shape, and the width of the protrusion may be smaller than a diameter of the body.

[0080] According to an exemplary embodiment, a display device includes a circuit board and a plurality of light-emitting devices arranged on the circuit board, at least one of the light-emitting devices includes: a first substrate; a first LED sub-unit, arranged below the first substrate; a second LED sub-unit, arranged below the first LED sub-unit; a third LED sub-unit, arranged below the second LED sub-unit; a first transparent electrode, interposed between the first LED sub-unit and the second LED sub-unit, and in ohmic contact with the lower surface of the first LED sub-unit; a second transparent electrode, interposed between the second LED sub-unit and the third LED sub-unit, and in ohmic contact with the lower surface of the second LED sub-unit; a third transparent electrode, interposed between the first LED sub-unit and the third LED sub-unit, and in ohmic contact with the lower surface of the second LED sub-unit; and a third transparent electrode, interposed between the second LED sub-unit and the third LED sub-unit. between the second transparent electrode and the third LED sub-unit, and in ohmic contact with the upper surface of the third LED sub-unit; at least one current diffusion member, connected to at least one of the first LED sub-unit, the second LED sub-unit and the third LED sub-unit; an electrode pad, arranged on the first substrate; and a through-hole passage, formed through the first substrate, to electrically connect the electrode pad to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit, wherein at least one of the through-hole passages is formed through the first substrate, the first LED sub-unit and the second LED sub-unit, and the electrode pad of the light-emitting device is electrically connected to the circuit board.

[0081] Each of the light emitting devices may further include: a second substrate coupled to the third LED sub-unit.

[0082] According to an exemplary embodiment, a light-emitting device for a display includes: a first substrate; a first LED sub-unit, arranged below the first substrate; a second LED sub-unit, arranged below the first LED sub-unit; a third LED sub-unit, arranged below the second LED sub-unit; an electrode pad, arranged above the first substrate; a through-hole passage, passing through the first substrate to electrically connect the electrode pad to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit; and a heat exchange element, arranged above the first LED sub-unit, at least a portion of each of the heat exchange elements being arranged inside the first substrate, wherein at least one of the through-hole passages passes through the first substrate, the first LED sub-unit and the second LED sub-unit.

[0083] The first, second, and third LED sub-units may include first, second, and third LED stacks configured to emit red, green, and blue light, respectively, and the heat exchanging element may include a heat pipe.

[0084] The light emitting device may include a distributed Bragg reflector between the first substrate and the first LED subunit, wherein the heat exchanging element may be disposed on the distributed Bragg reflector.

[0085] The first substrate may be a GaAs substrate.

[0086] The light emitting device may further include a second substrate disposed under the third LED sub-unit.

[0087] The second substrate may be a sapphire substrate or a GaN substrate.

[0088] The first LED sub-unit, the second LED sub-unit and the third LED sub-unit may be independently drivable, the light generated from the first LED sub-unit may be configured to be emitted to the outside of the light-emitting device through the second LED sub-unit, the third LED sub-unit and the second substrate, and the light generated from the second LED sub-unit may be configured to be emitted to the outside of the light-emitting device through the third LED sub-unit and the second substrate.

[0089] The electrode pad may include: a common electrode pad, which is electrically connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit; and a first electrode pad, a second electrode pad and a third electrode pad, which are electrically connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit respectively.

[0090] The common electrode pad may be electrically connected to a plurality of through-hole vias.

[0091] The second electrode pad can be electrically connected to the second LED sub-unit via a through-hole path formed through the first substrate and the first LED sub-unit, and the third electrode pad can be electrically connected to the third LED sub-unit via a through-hole path formed through the first substrate, the first LED sub-unit and the second LED sub-unit.

[0092] The first electrode pad may be electrically connected to the first substrate, and the heat exchange element may be electrically insulated from the common electrode pad, the second electrode pad, and the third electrode pad.

[0093] The first electrode pad may be electrically connected to the first LED sub-unit through a through-hole via passing through the first substrate, and the heat exchange element may be electrically connected to the common electrode pad and electrically insulated from the first electrode pad.

[0094] The through-hole via may be insulated from the substrate by an insulating layer inside the substrate, and the heat exchange element may contact the substrate inside the substrate.

[0095] The through-hole passage and the heat exchange element may be insulated from the substrate by the insulating layer inside the substrate.

[0096] The light-emitting device may also include: a first transparent electrode, which is interposed between the first LED sub-unit and the second LED sub-unit and is in ohmic contact with the lower surface of the first LED sub-unit; a second transparent electrode, which is interposed between the second LED sub-unit and the third LED sub-unit and is in ohmic contact with the lower surface of the second LED sub-unit; a third transparent electrode, which is interposed between the second transparent electrode and the third LED sub-unit and is in ohmic contact with the upper surface of the third LED sub-unit; and at least one current diffusion member, which is connected to at least one of the first LED sub-unit, the second LED sub-unit and the third LED sub-unit.

[0097] The at least one current diffuser may include a first current diffuser connected to the first LED subunit, a second current diffuser connected to the second LED subunit, and a third current diffuser connected to the third LED subunit, and the first current diffuser, the second current diffuser and the third current diffuser may be isolated from the first transparent electrode, the second transparent electrode and the third transparent electrode, respectively.

[0098] One of the electrode pads disposed on the first substrate may be electrically connected to the first transparent electrode, the second transparent electrode, and the third transparent electrode through the through-hole via.

[0099] The light emitting device may further include: a first color filter disposed between the third transparent electrode and the second transparent electrode; and a second color filter disposed between the second LED subunit and the first transparent electrode.

[0100] The light emitting device may further include an insulating layer interposed between the first substrate and the electrode pad and covering side surfaces of the first LED sub-unit, the second LED sub-unit, and the third LED sub-unit.

[0101] According to an exemplary embodiment, a light-emitting device for a display includes: a first substrate; a first LED sub-unit, which is arranged below the first substrate; a second LED sub-unit, which is arranged below the first LED sub-unit; a third LED sub-unit, which is arranged below the second LED sub-unit; and a heat exchange element, at least a portion of each of the heat exchange elements is arranged inside the first substrate, wherein the heat exchange element is arranged above the first LED sub-unit.

[0102] The light emitting device may further include: an electrode pad disposed on the first substrate; and a through-hole via electrically connecting the electrode pad to the first LED sub-unit, the second LED sub-unit, and the third LED sub-unit, wherein the heat exchange element includes a heat pipe.

[0103] The light emitting device may further include a second substrate disposed below the third LED sub-unit, wherein the first substrate may be a GaAs substrate, and the second substrate may be a sapphire substrate or a GaN substrate.

[0104] The light-emitting device may also include: a first transparent electrode, which is interposed between the first LED sub-unit and the second LED sub-unit and is in ohmic contact with the lower surface of the first LED sub-unit; a second transparent electrode, which is interposed between the second LED sub-unit and the third LED sub-unit and is in ohmic contact with the lower surface of the second LED sub-unit; a third transparent electrode, which is interposed between the second transparent electrode and the third LED sub-unit and is in ohmic contact with the upper surface of the third LED sub-unit; and at least one current diffusion member, which is connected to at least one of the first LED sub-unit, the second LED sub-unit and the third LED sub-unit.

[0105] The light emitting device may include a micro-LED having a surface area less than approximately 10,000 square microns, the first LED sub-unit may be configured to emit any one of red light, green light, and blue light, the second LED sub-unit may be configured to emit one of red light, green light, and blue light different from the first LED sub-unit, and the third LED sub-unit may be configured to emit one of red light, green light, and blue light different from the first LED sub-unit and the second LED sub-unit.

[0106] The display apparatus may include a circuit board and a plurality of light emitting devices arranged on the circuit board, and at least one of the light emitting devices may include the light emitting device according to the exemplary embodiment.

[0107] The electrode pad may be electrically connected to the circuit board.

[0108] Each of the light emitting devices may further include a second substrate coupled to the third LED sub-unit.

[0109] A light emitting device for a display according to an exemplary embodiment includes: a first substrate; a first LED sub-unit, disposed below the first substrate; a second LED sub-unit, disposed below the first LED sub-unit; a third LED sub-unit, disposed below the second LED sub-unit; a first ohmic electrode, interposed between the first LED sub-unit and the second LED sub-unit, and in ohmic contact with a lower surface of the first LED sub-unit; a second ohmic electrode, interposed between the second LED sub-unit and the third LED sub-unit, and in ohmic contact with a lower surface of the second LED sub-unit; a third ohmic electrode, interposed between the second ohmic electrode and the third LED sub-unit, and in ohmic contact with an upper surface of the third LED sub-unit; an electrode pad, disposed on the first substrate; and a through-hole via, formed through the first substrate, to electrically connect the electrode pad to the first LED sub-unit, the second LED sub-unit, and the third LED sub-unit, wherein at least one of the through-hole vias is formed through the first substrate, the first LED sub-unit, and the second LED sub-unit, and at least one of the first ohmic electrode, the second ohmic electrode, and the third ohmic electrode has a mesh structure.

[0110] The first LED sub-unit, the second LED sub-unit, and the third LED sub-unit may respectively include a first LED stack configured to emit red light, a second LED stack configured to emit green light, and a third LED stack configured to emit blue light.

[0111] The light emitting device may further include a distributed Bragg reflector interposed between the first substrate and the first LED subunit.

[0112] The first substrate may be a GaAs substrate.

[0113] The light emitting device may further include a second substrate disposed under the third LED sub-unit.

[0114] The second substrate may be a sapphire substrate or a GaN substrate.

[0115] The first LED sub-unit, the second LED sub-unit and the third LED sub-unit may be independently drivable, the light generated from the first LED sub-unit may be configured to be emitted to the outside of the light-emitting device through the second LED sub-unit, the third LED sub-unit and the second substrate, and the light generated from the second LED sub-unit may be configured to be emitted to the outside of the light-emitting device through the third LED sub-unit and the second substrate.

[0116] The electrode pad may include: a common electrode pad, which is electrically connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit; and a first electrode pad, a second electrode pad and a third electrode pad, which are electrically connected to the first LED sub-unit, the second LED sub-unit and the third LED sub-unit respectively.

[0117] The common electrode pad may be electrically connected to a plurality of through-hole vias.

[0118] The second electrode pad can be electrically connected to the second LED sub-unit via a through-hole path formed through the first substrate and the first LED sub-unit, and the third electrode pad can be electrically connected to the third LED sub-unit via a through-hole path formed through the first substrate, the first LED sub-unit and the second LED sub-unit.

[0119] The first electrode pad may be electrically connected to the first substrate.

[0120] The first electrode pad may be electrically connected to the first LED sub-unit through a through-hole via formed through the first substrate.

[0121] The first ohmic electrode may have a mesh structure and include Au—Zn or Au—Be, and the second ohmic electrode may have a mesh structure and include Pt or Rh.

[0122] One of the electrode pads disposed on the first substrate may be electrically connected to the first ohmic electrode, the second ohmic electrode, and the third ohmic electrode through a plurality of through-hole vias.

[0123] One of the electrode pads disposed on the first substrate may be connected to the first substrate.

[0124] The light emitting device may further include: a first color filter disposed between the third ohmic electrode and the second ohmic electrode; and a second color filter disposed between the second LED sub-unit and the first ohmic electrode.

[0125] The first color filter and the second color filter may include insulating layers having different refractive indices.

[0126] The light emitting device may further include: an insulating layer disposed between the first substrate and the electrode pad and covering side surfaces of the first LED sub-unit, the second LED sub-unit, and the third LED sub-unit.

[0127] The display apparatus may include a circuit board and a plurality of light emitting devices arranged on the circuit board, at least one of the light emitting devices may include the light emitting device according to the exemplary embodiment, wherein the electrode pad may be electrically connected to the circuit board.

[0128] Each of the light emitting devices may further include a second substrate coupled to the third LED sub-unit.

[0129] According to an exemplary embodiment, a light-emitting device for a display includes: a first substrate; a first LED sub-unit, which is arranged below the first substrate; a second LED sub-unit, which is arranged below the first LED sub-unit; a third LED sub-unit, which is arranged below the second LED sub-unit; a first ohmic electrode, which is between the first LED sub-unit and the second LED sub-unit and is in ohmic contact with the lower surface of the first LED sub-unit; a second ohmic electrode, which is between the second LED sub-unit and the third LED sub-unit and is in ohmic contact with the lower surface of the second LED sub-unit; a third ohmic electrode, which is between the second ohmic electrode and the third LED sub-unit and is in ohmic contact with the upper surface of the third LED sub-unit; a second substrate, which is arranged below the third LED sub-unit, wherein at least one of the first ohmic electrode, the second ohmic electrode and the third ohmic electrode has a grid structure.

[0130] The first substrate may be a GaAs substrate, and the second substrate may be a sapphire substrate or a GaN substrate.

[0131] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

[0132] Beneficial effects of the present invention

[0133] A light emitting diode and a display using the same constructed according to the principles and some exemplary embodiments of the present invention can increase the area of ​​each sub-pixel without increasing the area of ​​a pixel.

[0134] Light emitting diodes and displays using the same, such as micro-LEDs, constructed in accordance with the principles and some exemplary embodiments of the present invention can reduce the amount of time associated with mounting light emitting devices on circuit boards during manufacturing.

[0135] Light emitting diodes and displays using the same, such as micro-LEDs, constructed according to the principles and some exemplary embodiments of the present invention include one or more structures for improving current distribution.

[0136] Light emitting diodes and displays using the same, such as micro-LEDs, constructed according to the principles and some exemplary embodiments of the present invention include structures for improving heat dissipation.

[0137] Light emitting diodes and displays using the same, such as micro-LEDs, constructed according to the principles and some exemplary embodiments of the present invention include a mesh structure for improving light efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0138] The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate exemplary embodiments of the invention and together with the description serve to explain the inventive concept.

[0139] Figure 1 is a schematic plan view of a display device according to an exemplary embodiment.

[0140] Figure 2A is a schematic plan view of a light emitting device according to an exemplary embodiment.

[0141] Figure 2B It is along Figure 2A A schematic cross-sectional view taken along line AA.

[0142] Figure 3A , Figure 3B , Figure 4A , Figure 4B , Figure 5A , Figure 5B , Fig. 6A , Figure 6B , Fig. 7A , Figure 7B , Fig. 8A , Figure 8B , Fig.9A , Fig. 9B , Fig. 10A , Fig. 10B , Fig.11A , Fig. 11B , Fig. 12A , Fig. 12B , Fig.13A and Fig. 13B are schematic plan views and cross-sectional views illustrating a method of manufacturing a light emitting device according to an exemplary embodiment.

[0143] Fig.14 is a schematic plan view of a display device according to an exemplary embodiment.

[0144] Fig.15A is a schematic plan view of a light emitting device according to an exemplary embodiment.

[0145] Fig. 15B It is along Fig.15A A schematic cross-sectional view taken along line AB.

[0146] Fig.16A , Fig. 16B , Fig.17A , Fig. 17B , Fig.18A , Fig.18B , Fig.19A , Fig.19B , Fig. 20A , Fig. 20B , Fig.21A , Fig. 21B , Fig.22A , Fig. 22B , Fig.23A , Fig. 23B , Fig.24A , Fig. 24B , Fig.25A , Fig.25B , Fig.26A and Fig.26B are schematic plan views and cross-sectional views illustrating a method of manufacturing a light emitting device according to an exemplary embodiment.

[0147] Fig.27A is a schematic plan view of a light emitting device for a display according to another exemplary embodiment.

[0148] Fig.27B It is along Fig.27A A schematic cross-sectional view taken along line AB.

[0149] Fig.28A , Fig.28B , Fig.29A , Fig.29B , Fig. 30A , Fig. 30B , Fig.31A , Fig.31B , Fig.32A , Fig.32B , Fig.33A , Fig.33B , Fig.34A and Fig.34B are schematic plan views and cross-sectional views illustrating a method of manufacturing a light emitting device according to another exemplary embodiment.

[0150] Fig.35A is a plan view of a light emitting diode stack structure according to another exemplary embodiment.

[0151] Fig.35B It is along Fig.35A Schematic cross-sectional view taken along line AB.

[0152] Fig.36A is a schematic plan view of a light emitting device according to still another exemplary embodiment.

[0153] Fig.36B and Fig.36C Along the Fig.36A Schematic cross-sectional view taken along line GH and line IJ.

[0154] Fig.37 is a schematic plan view of a display device according to an exemplary embodiment.

[0155] Fig.38A is a schematic plan view of a light emitting device for a display according to an exemplary embodiment.

[0156] Fig.38B It is along Fig.38A A schematic cross-sectional view taken along line AA.

[0157] Fig.39A , Fig.39B , Fig.40A , Fig.40B , Fig.41A , Fig.41B , Fig.42 , Fig.43 , Fig.44 , Fig.45A , Fig.45B , Fig.46A , Fig.46B , Fig.47A , Fig.47B , Fig.48A , Fig.48B , Fig.49A and Fig.49B are schematic plan views and cross-sectional views illustrating a method of manufacturing a light emitting device for a display according to an exemplary embodiment.

[0158] Fig.50A and Fig.50B are a schematic plan view and a cross-sectional view, respectively, of a light emitting device for a display according to another exemplary embodiment.

[0159] Fig.51 is a schematic plan view of a display device according to an exemplary embodiment.

[0160] Fig.52A is a schematic plan view of a light emitting device for a display according to an exemplary embodiment.

[0161] Fig.52B It is along Fig.52A A schematic cross-sectional view taken along line AA.

[0162] Fig.53A , Fig.53B , Fig.54A , Fig.54B , Fig.55A , Fig.55B , Fig.56 , Fig.57 , Fig.58 , Fig.59A , Fig.59B , Fig.60A , Fig.60B , Fig.61A , Fig.61B , Fig.62A , Fig.62B , Fig.63A , Fig.63B , Fig.64A , Fig.64B , Fig.65A and Fig.65B are schematic plan views and cross-sectional views illustrating a method of manufacturing a light emitting device for a display according to an exemplary embodiment.

[0163] Fig.66A and Fig.66B are schematic plan views and cross-sectional views illustrating a light emitting device for a display according to another exemplary embodiment.

[0164] Fig.67A and Fig.67B are schematic plan views and cross-sectional views illustrating a light emitting device for a display according to another exemplary embodiment.

[0165] Fig.68A and Fig.68B are schematic plan views and cross-sectional views illustrating a light emitting device for a display according to another exemplary embodiment.

[0166] Fig.69 is a schematic plan view of a display device according to an exemplary embodiment.

[0167] Fig.70A is a schematic plan view of a light emitting device for a display according to an exemplary embodiment.

[0168] Fig.70B It is along Fig.70A A schematic cross-sectional view taken along line AA.

[0169] Fig.71A , Fig.71B , Fig.72A , Fig.72B , Fig.73A , Fig.73B , Fig.74 , Fig.75 , Fig.76 , Fig.77A , Fig.77B , Fig.78A , Fig.78B , Fig.79A , Fig.79B , Fig.80A , Fig.80B , Fig.81A and Fig.81B are schematic plan views and cross-sectional views illustrating a method of manufacturing a light emitting device for a display according to an exemplary embodiment.

[0170] Fig.82A and Fig.82B are a schematic plan view and a cross-sectional view, respectively, of a light emitting device for a display according to another exemplary embodiment. DETAILED DESCRIPTION

[0171] In the following description, for the purpose of illustration, many specific details are set forth to provide a thorough understanding of various exemplary embodiments or implementations of the present invention. As used herein, "embodiment" and "implementation" are interchangeable words, which are non-limiting examples of devices or methods using one or more inventive concepts disclosed herein. However, it is apparent that various exemplary embodiments can be practiced without these specific details or using one or more equivalent arrangements. In other cases, well-known structures and devices are shown in block diagram form to avoid unnecessary obscurity of various exemplary embodiments. In addition, various exemplary embodiments may be different, but do not have to be exclusive. For example, without departing from the inventive concept, the specific shape, configuration and characteristics of the exemplary embodiment may be used or implemented in another exemplary embodiment.

[0172] Unless otherwise specified, the exemplary embodiments shown will be understood as providing exemplary features of different details of some ways in which the inventive concept can be implemented in practice. Therefore, unless otherwise specified, the features, components, modules, layers, films, panels, regions and / or aspects of the various embodiments (hereinafter, individually or collectively referred to as "elements") can be combined, separated, interchanged and / or rearranged without departing from the inventive concept.

[0173] The use of cross hatching and / or shading in the drawings is generally provided to clarify the boundaries between adjacent elements. Thus, unless otherwise specified, the presence or absence of cross hatching or shading does not convey or indicate any preference or requirement for the specific material, material properties, size, ratio, commonality between the elements shown, and / or any other characteristics, attributes, properties, etc. of the elements. In addition, in the drawings, the size and relative size of the elements may be exaggerated for clarity and / or descriptive purposes. When the exemplary embodiments can be implemented differently, a specific process sequence can be performed differently from the described sequence. For example, two processes described in succession can be performed substantially simultaneously or in an order opposite to the described sequence. In addition, the same reference numerals represent the same elements.

[0174] When an element such as a layer is referred to as being "on" another element or layer, "connected to" or "bonded to" another element or layer, the element may be directly on, directly connected to or directly bonded to another element or layer, or there may be an intermediate element or layer. However, when an element or layer is referred to as being "directly on", "directly connected to" or "directly bonded to" another element or layer, there is no intermediate element or layer. For this reason, the term "connection" may refer to a physical connection, an electrical connection and / or a fluid connection with or without an intermediate element. In addition, the D1 axis, the D2 axis and the D3 axis are not limited to the three axes of a rectangular coordinate system, such as an x-axis, a y-axis and a z-axis, and may be interpreted in a broader sense. For example, the D1 axis, the D2 axis and the D3 axis may be perpendicular to each other, or may represent different directions that are not perpendicular to each other. For the purpose of this disclosure, "at least one of X, Y, and Z" and "at least one selected from the group consisting of X, Y, and Z" may be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y, and Z, such as XYZ, XYY, YZ, and ZZ. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0175] Although the terms "first", "second", etc. may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Therefore, without departing from the teachings of the present disclosure, the first element discussed below may be named as the second element.

[0176] For descriptive purposes, spatially relative terms such as "below," "beneath," "under," "down," "above," "upper," "above," "higher," "side" (e.g., as in "sidewall"), etc. may be used herein to describe the relationship of one element to other elements as shown in the figures. In addition to the orientations depicted in the accompanying drawings, spatially relative terms are intended to cover different orientations of the device in use, operation, and / or manufacture. For example, if the device is turned over in the accompanying drawings, elements described as being "below" or "below" other elements or features will subsequently be positioned as being "above" the other elements or features. Thus, the exemplary term "below" may cover both "above" and "below" orientations. In addition, the device may be otherwise positioned (e.g., rotated 90 degrees or at other orientations), so that the spatially relative descriptors used herein are interpreted accordingly.

[0177] The terms used here are for the purpose of describing specific embodiments and are not intended to be restrictive. As used here, unless the context clearly indicates otherwise, the singular forms "one", "a kind of" and "the" are also intended to include plural forms. In addition, when the terms "comprise", "include", "have" and / or "contain" are used in this specification, it is indicated that there are stated features, wholes, steps, operations, elements, components and / or their groups, but it is not excluded that there are or add one or more other features, wholes, steps, operations, elements, components and / or their groups. It is also noted that, as used here, the terms "substantially", "approximately" and other similar terms are used as approximate terms rather than degree terms, so as to explain the inherent deviations of measured values, calculated values ​​and / or set values ​​that will be recognized by those of ordinary skill in the art.

[0178] Various exemplary embodiments are described herein with reference to cross-sectional views and / or exploded views that are schematic diagrams of idealized exemplary embodiments and / or intermediate structures. As such, variations in the shapes of the views due to, for example, manufacturing techniques and / or tolerances are anticipated. Therefore, the exemplary embodiments disclosed herein should not necessarily be construed as being limited to the specific illustrated shapes of the regions, but will include shape deviations, for example, caused by manufacturing. In this manner, the regions illustrated in the drawings may be schematic in nature, and the shapes of these regions may not reflect the actual shapes of the regions of the device and, therefore, are not necessarily intended to be restrictive.

[0179] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this disclosure is a part. Unless explicitly defined as such herein, terms such as those defined in general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense.

[0180] Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. As used herein, a light emitting device or light emitting diode according to an exemplary embodiment may include a micro-LED having a surface area of ​​less than about 10,000 square microns as known in the art. In other exemplary embodiments, the surface area of ​​the micro-LED may be less than about 4,000 square microns, or less than about 2,500 square microns, depending on the specific application. In addition, the light emitting device may be mounted in various configurations such as flip-chip bonding, and therefore, the inventive concept is not limited to the specific stacking order of the first LED stack, the second LED stack, and the third LED stack.

[0181] Figure 1 is a schematic plan view illustrating a display device according to an exemplary embodiment.

[0182] Reference Figure 1 , the display device includes a circuit board 101 and a plurality of light emitting devices 100 .

[0183] The circuit board 101 may include circuits for passive matrix driving or active matrix driving. In one exemplary embodiment, the circuit board 101 may include wiring and resistors disposed therein. In another exemplary embodiment, the circuit board 101 may include wiring, transistors, and capacitors. The circuit board 101 may also have pads disposed on its upper surface to allow electrical connection to the circuits disposed therein.

[0184] A plurality of light emitting devices 100 are arranged on a circuit board 101. Each light emitting device 100 may constitute a pixel. The light emitting device 100 has electrode pads 81a, 81b, 81c, and 81d electrically connected to the circuit board 101. The light emitting device 100 may further include a substrate 41 disposed on an upper surface thereof. The light emitting devices 100 are spaced apart from each other so that the substrates 41 disposed on the upper surfaces of the light emitting devices 100 are also spaced apart from each other.

[0185] Will refer to Figure 2A and Figure 2B The configuration of the light emitting device 100 according to the exemplary embodiment is described in detail. Figure 2A is a schematic plan view of a light emitting device 100 according to an exemplary embodiment, Figure 2B It is along Figure 2A1. A cross-sectional view taken along line AA of FIG. 1. Although the electrode pads 81a, 81b, 81c, and 81d are shown as being arranged on the upper side of the light emitting device 100, the inventive concept is not limited thereto. For example, the light emitting device 100 may be flip-chip bonded to the circuit board 101, in which case the electrode pads 81a, 81b, 81c, and 81d may be arranged on the lower side of the light emitting device 100.

[0186] Reference Figure 2A and Figure 2B The light emitting device 100 includes a substrate 41, electrode pads 81a, 81b, 81c and 81d, a first LED stack 23, a second LED stack 33, a third LED stack 43, an insulating layer 25, a protective layer 29, a first reflective electrode 26, a second transparent electrode 35, a third transparent electrode 45, a first ohmic electrode 28 and a third ohmic electrode 48, a 2-1 current distribution layer 36, a 2-2 current distribution layer 38, a third current distribution layer 46, a first color filter 47, a second color filter 67, a first bonding layer 49, a planarization layer 39, a second bonding layer 69 and an upper insulating layer 71.

[0187] The substrate 41 may support the LED stacks 23, 33, and 43. The substrate 41 may be a growth substrate on which the third LED stack 43 is grown. For example, the substrate 41 may be a sapphire substrate or a gallium nitride substrate, specifically, a patterned sapphire substrate. The first LED stack 23, the second LED stack 33, and the third LED stack 43 are arranged on the substrate 41 in the order of the third LED stack 43, the second LED stack 33, and the first LED stack 23. A single third LED stack may be provided on one substrate 41, and thus, the light emitting device 100 may have a single chip structure of a single pixel. In some exemplary embodiments, the substrate 41 may be omitted, and the lower surface of the third LED stack 43 may be exposed. In this case, a rough surface may be formed on the lower surface of the third LED stack 43 by surface texturing.

[0188] The first LED stack 23, the second LED stack 33, and the third LED stack 43 include first conductive semiconductor layers 23a, 33a, and 43a, second conductive semiconductor layers 23b, 33b, and 43b, and active layers interposed between the first conductive semiconductor layers 23a, 33a, and 43a and the second conductive semiconductor layers 23b, 33b, and 43b, respectively. The active layer may have a multi-quantum well structure.

[0189] According to an exemplary embodiment, the LED stack may emit light with a shorter wavelength as it is arranged closer to the substrate 41. For example, the first LED stack 23 may be an inorganic light emitting diode that emits red light, the second LED stack 33 may be an inorganic light emitting diode that emits green light, and the third LED stack 43 may be an inorganic light emitting diode that emits blue light. The first LED stack 23 may include a GaInP-based well layer, and the second LED stack 33 and the third LED stack 43 may include a GaInN-based well layer. However, the inventive concept is not limited thereto. When the light emitting device 100 includes a micro-LED having a surface area of ​​less than about 10,000 square microns, or less than about 4,000 square microns or 2,500 square microns as known in the art, the first LED stack 23 may emit any one of red light, green light, and blue light, and the second LED stack 33 and the third LED stack 43 may emit a different one of red light, green light, and blue light without negatively affecting the operation due to the small form factor of the micro-LED.

[0190] The first conductive semiconductor layers 23a, 33a, and 43a of each LED stack 23, 33, and 43 may be n-type semiconductor layers, and the second conductive semiconductor layers 23b, 33b, and 43b of each LED stack 23, 33, and 43 may be p-type semiconductor layers. In the illustrated exemplary embodiment, the upper surface of the first LED stack 23 may be a p-type semiconductor layer 23b, the upper surface of the second LED stack 33 may be an n-type semiconductor layer 33a, and the upper surface of the third LED stack 43 may be a p-type semiconductor layer 43b. More specifically, the order of the semiconductor layers may be reversed only in the second LED stack 33. According to exemplary embodiments, the first LED stack 23 and the third LED stack 43 may have first conductive semiconductor layers 23a and 43a including textured surfaces, respectively, to improve light extraction efficiency. In some exemplary embodiments, the second LED stack 33 may also have a first conductive semiconductor layer 33a including a textured surface, however, because the first conductive semiconductor layer 33a is disposed farther away from the substrate 41 than the second conductive semiconductor layer 33b, the effect produced by the surface texturing may not be significant. Specifically, when the second LED stack 33 emits green light, the green light has higher visibility than red light or blue light. Therefore, the first LED stack 23 and the third LED stack 43 can be formed to have higher luminous efficiency than the second LED stack 33. In this way, the luminous intensities of red light, green light, and blue light can be adjusted to be substantially consistent with each other by applying surface texturing to a greater extent in the first LED stack 23 and the third LED stack 43 than in the second LED stack 33.

[0191] In addition, in the first LED stack 23 and the third LED stack 43, the second conductive semiconductor layers 23b and 43b may be disposed on partial regions of the first conductive semiconductor layers 23a and 43a, so that the first conductive semiconductor layers 23a and 43a are partially exposed. Alternatively, in the case of the second LED stack 33, the first conductive semiconductor layer 33a and the second conductive semiconductor layer 33b may completely overlap each other.

[0192] The first LED stack 23 is disposed away from the substrate 41, the second LED stack 33 is disposed below the first LED stack 23, and the third LED stack 43 is disposed below the second LED stack 33. According to an exemplary embodiment, since the wavelength of light emitted by the first LED stack 23 is longer than the wavelength of light emitted by the second LED stack 33 and the third LED stack 43, light generated in the first LED stack 23 may be emitted to the outside through the second LED stack 33, the third LED stack 43, and the substrate 41. In addition, since the wavelength of light emitted by the second LED stack 33 is longer than the wavelength of light emitted by the third LED stack 43, light generated in the second LED stack 33 may be emitted to the outside through the third LED stack 43 and the substrate 41.

[0193] The insulating layer 25 is disposed on the first LED stack 23 and has at least one opening exposing the second conductive type semiconductor layer 23b of the first LED stack 23. The insulating layer 25 may have a plurality of openings distributed on the first LED stack 23. The insulating layer 25 may be a transparent insulating layer having a lower refractive index than the first LED stack 23.

[0194] The first reflective electrode 26 makes ohmic contact with the second conductive semiconductor layer 23b of the first LED stack 23 and reflects light generated in the first LED stack 23 toward the substrate 41. The first reflective electrode 26 is disposed on the insulating layer 25 and connected to the first LED stack 23 through an opening of the insulating layer 25.

[0195] The first reflective electrode 26 may include an ohmic contact layer 26a and a reflective layer 26b. The ohmic contact layer 26a partially contacts the second conductive semiconductor layer 23b, such as a p-type semiconductor layer. The ohmic contact layer 26a may be formed with a limited area to prevent light from being absorbed by the ohmic contact layer 26a. The ohmic contact layer 26a may be formed on the second conductive semiconductor layer 23b exposed in the opening of the insulating layer 25. The ohmic contact layers 26a spaced apart from each other may be formed in a plurality of regions of the first LED stack 23 to facilitate current distribution in the second conductive semiconductor layer 23b. The ohmic contact layer 26a may be formed of a transparent conductive oxide or an Au alloy such as Au(Zn) or Au(Be).

[0196] The reflective layer 26b covers the ohmic contact layer 26a and the insulating layer 25. The reflective layer 26b covers the insulating layer 25 so that an omnidirectional reflector can be formed by the stacked structure of the first LED stack 23 having a relatively high refractive index, the insulating layer 25 having a relatively low refractive index, and the reflective layer 26b. The reflective layer 26b may include a reflective metal layer such as Al, Ag, or Au. In addition, the reflective layer 26b may include an adhesive metal layer such as Ti, Ta, Ni, or Cr located on the upper and lower surfaces of the reflective metal layer to improve the adhesion of the reflective metal layer. Au is particularly suitable for forming the reflective layer 26b in the first LED stack 23 due to its high reflectivity for red light and low reflectivity for blue or green light. The reflective layer 26b may cover 50% or more of the area of ​​the first LED stack 23, and in some exemplary embodiments, may cover most of the first LED stack 23 to improve light efficiency.

[0197] The ohmic contact layer 26a and the reflective layer 26b may be formed of a metal layer including Au. The reflective layer 26b may be formed of a metal layer having a high reflectivity for light (e.g., red light) generated in the first LED stack 23. The reflective layer 26b may have a low reflectivity for light (e.g., green light or blue light) generated in the second LED stack 33 and the third LED stack 43. Therefore, the reflective layer 26b may absorb light generated in the second LED stack 33 and the third LED stack 43 and incident on the reflective layer 26b to reduce or prevent light interference.

[0198] The first ohmic electrode 28 is disposed on the exposed first conductive type semiconductor layer 23a and is in ohmic contact with the first conductive type semiconductor layer 23a. The first ohmic electrode 28 may also be formed of a metal layer including Au.

[0199] The protective layer 29 may protect the first reflective electrode 26 by covering the first reflective electrode 26. However, the protective layer 29 may expose the first ohmic electrode 28.

[0200] The second transparent electrode 35 makes ohmic contact with the second conductive semiconductor layer 33b of the second LED stack 33. The second transparent electrode 35 may contact the lower surface of the second LED stack 33 between the second LED stack 33 and the third LED stack 43. The second transparent electrode 35 may be formed of a metal layer or a conductive oxide layer transparent to red and green light.

[0201] The third transparent electrode 45 is in ohmic contact with the second conductive semiconductor layer 43b of the third LED stack 43. The third transparent electrode 45 may be disposed between the second LED stack 33 and the third LED stack 43, and may contact the upper surface of the third LED stack 43. The third transparent electrode 45 may be formed of a metal layer or a conductive oxide layer that is transparent to red and green light. The third transparent electrode 45 may also be transparent to blue light. The second transparent electrode 35 and the third transparent electrode 45 may be in ohmic contact with the p-type semiconductor layer of each LED stack to facilitate current distribution. Examples of the conductive oxide layer for the second transparent electrode 35 and the third transparent electrode 45 may include SnO2, InO2, ITO, ZnO, IZO, and the like.

[0202] The first color filter 47 may be disposed between the third transparent electrode 45 and the second LED stack 33, and the second color filter 67 may be disposed between the second LED stack 33 and the first LED stack 23. The first color filter 47 may transmit light generated in the first LED stack 23 and the second LED stack 33, and reflect light generated in the third LED stack 43. The second color filter 67 may transmit light generated in the first LED stack 23, and reflect light generated in the second LED stack 33. Therefore, light generated in the first LED stack 23 may be emitted to the outside through the second LED stack 33 and the third LED stack 43, and light generated in the second LED stack 33 may be emitted to the outside through the third LED stack 43. In addition, light generated in the second LED stack 33 may be prevented from being lost due to being incident on the first LED stack 23, or light generated in the third LED stack 43 may be prevented from being lost due to being incident on the second LED stack 33.

[0203] In some exemplary embodiments, the second color filter 67 may reflect light generated in the third LED stack 43 .

[0204] The first color filter 47 and the second color filter 67 can be, for example, a low-pass filter that only passes a low frequency range (i.e., a long wave band), a band-pass filter that only passes a predetermined wave band, or a band-stop filter that only blocks a predetermined wave band. Specifically, the first color filter 47 and the second color filter 67 can be formed by alternately stacking insulating layers with different refractive indices from each other, for example, can be formed by alternately stacking TiO2 insulating layers and SiO2 insulating layers. Specifically, the first color filter 47 and the second color filter 67 may include a distributed Bragg reflector (DBR). The stop band of the distributed Bragg reflector can be controlled by adjusting the thickness of TiO2 and SiO2. The low-pass filter and the band-pass filter can also be formed by alternately stacking insulating layers with different refractive indices from each other.

[0205] The 2-1st current distribution layer 36 may be disposed on a lower surface of the second transparent electrode 35 . The 2-1st current distribution layer 36 may be electrically connected to the second conductive type semiconductor layer 33 b of the second LED stack 33 through the second transparent electrode 35 .

[0206] The 2-2nd current distribution layer 38 may be disposed on the second color filter 67, pass through the second color filter 67, and be electrically connected to the first conductive semiconductor layer 33a of the second LED stack 33. The second color filter 67 may have an opening exposing the second LED stack 33, and the 2-2nd current distribution layer 38 may be connected to the second LED stack 33 through the opening of the second color filter 67.

[0207] The third current distribution layer 46 may be disposed on the first color filter 47, pass through the first color filter 47, and be connected to the second conductive semiconductor layer 43b of the third LED stack 43. The first color filter 47 may have an opening exposing the third LED stack 43, and the third current distribution layer 46 may be connected to the third LED stack 43 through the opening of the first color filter 47.

[0208] The current distribution layers 36, 38, and 46 may be formed of a metal layer to facilitate current distribution. For example, the 2-1st current distribution layer 36 may include a pad region 36a and an extension portion 36b extending from the pad region 36a (see Figure 4A ). The 2-2 current distribution layer 38 includes a pad region 38a and an extension portion 38b extending from the pad region 38a, and the third current distribution layer 46 includes a pad region 46a and an extension portion 46b extending from the pad region 46a. The pad regions 36a, 38a, and 46a are regions to which the electrode pads 81d and 81b can be connected, and the extension portions 36b, 38b, and 46b can contribute to current distribution. The extension portions 36b, 38b, and 46b can be formed in various shapes so that the current can be evenly distributed in the second stack 33 and the third stack 43.

[0209] The planarization layer 39 covers the 2-1st current distribution layer 36 under the second LED stack 33 and provides a flat surface. The planarization layer 39 may be formed of a transparent layer and may be formed of SiO2, spin-on glass (SOG), or the like.

[0210] The first bonding layer 49 bonds the second LED stack 33 to the third LED stack 43. The first bonding layer 49 covers the first color filter 47 and is bonded to the planarization layer 39. The planarization layer 39 may also be used as a bonding layer. For example, the first bonding layer 49 and the planarization layer 39 may be a transparent organic layer or a transparent inorganic layer and bonded to each other. Examples of organic layers may include SU8, poly(methyl methacrylate) (PMMA), polyimide, polyparaxylene, benzocyclobutene (BCB), etc., and examples of inorganic layers include Al2O3, SiO2, SiN x etc. The organic layer may be joined under high vacuum and high pressure, and the inorganic layer may be joined under high vacuum while the surface energy is reduced by using plasma or the like after the surface is planarized by, for example, a chemical mechanical polishing process.

[0211] The second bonding layer 69 bonds the second LED stack 33 to the first LED stack 23. As shown, the second bonding layer 69 may cover the second color filter 67 and the 2-2 current distribution layer 38. The second bonding layer 69 may be in contact with the first LED stack 23, but is not limited thereto. In some exemplary embodiments, another planarization layer may be disposed on the lower surface of the first LED stack 23, and the second bonding layer 69 may be bonded to the another planarization layer. The second bonding layer 69 and the another planarization layer may be formed of the same material as the first bonding layer 49 and the planarization layer 39 described above.

[0212] The upper insulating layer 71 covers the side surfaces and upper regions of the first LED stack 23, the second LED stack 33, and the third LED stack 43. The upper insulating layer 71 may be formed of SiO2, Si3N4, SOG, or the like. In some exemplary embodiments, the upper insulating layer 71 may include a light-reflecting material or a light-blocking material to prevent light interference with adjacent light-emitting devices. For example, the upper insulating layer 71 may include a distributed Bragg reflector that reflects red, green, and blue light, or a SiO2 layer having a reflective metal layer or a highly reflective organic layer deposited thereon. Alternatively, for example, the upper insulating layer 71 may include black epoxy as a light-blocking material. The light-blocking material may prevent light interference between light-emitting devices and improve the contrast of an image.

[0213] The upper insulating layer 71 has openings exposing the first ohmic electrode 28 , the first reflective electrode 26 , the third ohmic electrode 48 , the 2-1st current distribution layer 36 , the 2-2nd current distribution layer 38 , and the third current distribution layer 46 .

[0214] The electrode pads 81a, 81b, 81c, and 81d are disposed above the first LED stack 23 and are electrically connected to the first LED stack 23, the second LED stack 33, and the third LED stack 43. The electrode pads 81a, 81b, 81c, and 81d are disposed on the upper insulating layer 71 and may be connected to the first ohmic electrode 28, the first reflective electrode 26, the third ohmic electrode 48, the 2-1st current distribution layer 36, the 2-2 current distribution layer 38, and the third current distribution layer 46 exposed through the opening of the upper insulating layer 71.

[0215] For example, the first electrode pad 81a may be connected to the first ohmic electrode 28 through the opening of the upper insulating layer 71. The first electrode pad 81a may be electrically connected to the first conductive type semiconductor layer 23a of the first LED stack 23.

[0216] The second electrode pad 81 b may be connected to the 2-2 th current distribution layer 38 through the opening of the upper insulating layer 71. The second electrode pad 81 b may be electrically connected to the first conductive type semiconductor layer 33a of the second LED stack 33.

[0217] The third electrode pad 81 c may be connected to the third ohmic electrode 48 through the opening of the upper insulating layer 71 , and may be electrically connected to the first conductive type semiconductor layer 43 a of the third LED stack 43 .

[0218] The common electrode pad 81d may be commonly connected to the 2-1st current distribution layer 36, the third current distribution layer 46, and the first reflective electrode 26 through the opening. The common electrode pad 81d may be commonly electrically connected to the second conductive semiconductor layer 23b of the first LED stack 23, the second conductive semiconductor layer 33b of the second LED stack 33, and the second conductive semiconductor layer 43b of the third LED stack 43.

[0219] 2 , the common electrode pad 81 d may be connected to the upper surface of the third current distribution layer 46 and the upper surface of the 2-1st current distribution layer 36. Thus, the 2-1st current distribution layer 36 may have a substantially annular shape, and the common electrode pad 81 d may be connected to the third current distribution layer 46 through the central region of the 2-1st current distribution layer 36.

[0220] According to the exemplary embodiment shown, the first LED stack 23 is electrically connected to the electrode pads 81d and 81a, the second LED stack 33 is electrically connected to the electrode pads 81d and 81b, and the third LED stack 43 is electrically connected to the electrode pads 81d and 81c. In this way, the anode of the first LED stack 23, the anode of the second LED stack 33, and the anode of the third LED stack 43 are electrically connected to the electrode pad 81d in common, and the cathode of the first LED stack 23, the cathode of the second LED stack 33, and the cathode of the third LED stack 43 are electrically connected to the first electrode pad 81a, the second electrode pad 81b, and the third electrode pad 81c, respectively. In this way, the first LED stack 23, the second LED stack 33, and the third LED stack 43 can be driven individually.

[0221] Figure 3A , Figure 3B , Figure 4A , Figure 4B , Figure 5A , Figure 5B , Fig. 6A , Figure 6B , Fig. 7A , Figure 7B , Fig. 8A , Figure 8B , Fig.9A , Fig. 9B , Fig. 10A , Fig. 10B , Fig.11A , Fig. 11B , Fig. 12A , Fig. 12B , Fig.13A and Fig. 13B 1 is a schematic plan view and a cross-sectional view showing a method of manufacturing a light emitting device 100 according to an exemplary embodiment. Figure 1 Each cross-sectional view (except Figure 4B (except for the above) is taken along line AA of the corresponding plane. Figure 4B It is along Figure 4A A cross-sectional view taken along line BB.

[0222] Reference Figure 3A and Figure 3B , a first LED stack 23 is grown on a first substrate 21. The first substrate 21 may be, for example, a GaAs substrate. The first LED stack may be formed of a semiconductor layer based on AlGaInP and include a first conductive type semiconductor layer 23a, an active layer, and a second conductive type semiconductor layer 23b. The first conductive type may be an n-type, and the second conductive type may be a p-type.

[0223] An insulating layer 25 is formed on the first LED stack 23, and an opening may be formed thereon by patterning the insulating layer 25. For example, SiO2 is formed on the first LED stack 23, a photoresist is applied to the SiO2, and then a photoresist pattern is formed using photolithography and development. Then, the SiO2 may be patterned using the photoresist pattern as an etching mask to form the insulating layer 25 having the opening.

[0224] Then, an ohmic contact layer 26a is formed in the opening of the insulating layer 25. The ohmic contact layer 26a may be formed by a lift-off technique or the like. After the ohmic contact layer 26a is formed, a reflective layer 26b covering the ohmic contact layer 26a and the insulating layer 25 is formed. The reflective layer 26b may be formed of, for example, Au and may be formed using a lift-off technique or the like. The first reflective electrode 26 may be formed of the ohmic contact layer 26a and the reflective layer 26b.

[0225] As shown in the figure, the first reflective electrode 26 may have a shape in which four corners are removed from a rectangular light emitting device region. The ohmic contact layer 26a may be widely distributed at the lower portion of the first reflective electrode 26. Figure 3A and Figure 3B One light emitting device region is shown, but a plurality of light emitting device regions may be provided on the substrate 21, and the first reflective electrode 26 may be formed in each light emitting device region.

[0226] The protective layer 29 may cover the first reflective electrode 26. The protective layer 29 may protect the first reflective electrode 26 from the external environment. The protective layer 29 may be formed of, for example, SiO2, Si3N4, SOG, or the like.

[0227] Then, the protective layer 29 and the second conductive type semiconductor layer 23b may be etched to expose the first conductive type semiconductor layer 23a, and a first ohmic contact layer 28 is formed on the exposed first conductive type semiconductor layer 23a. The first ohmic electrode 28 makes ohmic contact with the first conductive type semiconductor layer 23a.

[0228] Reference Figure 4A and Figure 4B , a second LED stack 33 is grown on the second substrate 31, and a second transparent electrode 35 is formed on the second LED stack 33. The second LED stack 33 may be formed of a gallium nitride-based semiconductor layer, and may include a first conductive type semiconductor layer 33a, an active layer, and a second conductive type semiconductor layer 33b. The active layer may include a GaInN well layer. The first conductive type may be an n-type, and the second conductive type may be a p-type.

[0229] The second substrate 31 is a substrate on which a gallium nitride-based semiconductor layer can be grown, and can be different from the first substrate 21. The composition ratio of the GaInN well layer can be determined so that the second LED stack 33 can emit, for example, green light. The second transparent electrode 35 is in ohmic contact with the second conductive type semiconductor layer 33b.

[0230] The 2-1st current distribution layer 36 is formed on the second transparent electrode 35. The 2-1st current distribution layer 36 may be formed of a metal layer. The 2-1st current distribution layer 36 may include a pad region 36a and an extension portion 36b. The pad region 36a may have an opening 36h having a substantially annular shape and exposing the second transparent electrode 35. As shown in the figure, the extension portion 36b extends from the pad region 36a and may extend substantially in a diagonal direction, but is not limited thereto. The extension portion 36b may have various shapes. Although Figure 4A and Figure 4B One light emitting device region is shown, but a plurality of light emitting device regions may be provided on the substrate 31, and the 2-1st current distribution layer 36 may be formed in each light emitting device region.

[0231] A planarization layer 39 is formed covering the 2-1st current distribution layer 36 and the second transparent electrode 35. The planarization layer 39 provides a flat surface on the 2-1st current distribution layer 36. The planarization layer 39 may be formed of light-transmitting SOG or the like, and may be used as a bonding layer.

[0232] Reference Figure 5A and Figure 5B , a third LED stack 43 is grown on the third substrate 41, and a third transparent electrode 45 and a first color filter 47 are formed on the third LED stack 43. The third LED stack 43 may be formed of a gallium nitride-based semiconductor layer, and may include a first conductive type semiconductor layer 43a, an active layer, and a second conductive type semiconductor layer 43b. The active layer may further include a GaInN well layer. The first conductive type may be an n-type, and the second conductive type may be a p-type.

[0233] The third substrate 41 is a substrate on which a gallium nitride-based semiconductor layer can be grown, and may be different from the first substrate 21. The composition ratio of GaInN may be determined so that the third LED stack 43 emits, for example, blue light. The third transparent electrode 45 is in ohmic contact with the second conductive type semiconductor layer 43b.

[0234] Since the first color filter 47 is Figure 2A and Figure 2B The described first color filter 47 is substantially the same, so a detailed description thereof will be omitted to avoid redundancy.

[0235] The first color filter 47 may be patterned to form openings 47a, 47b, and 47c exposing the third transparent electrode 45. In addition, the third transparent electrode 45 and the second conductive type semiconductor layer 43b exposed in the opening 47a may be sequentially patterned to expose the first conductive type semiconductor layer 43a.

[0236] A third ohmic electrode 48 is formed on the exposed first conductive type semiconductor layer 43a, and a third current distribution layer 46 is formed. The third current distribution layer 46 contacts the third transparent electrode 45 through the openings 47b and 47c. The third current distribution layer 46 may include a pad region 46a and an extension portion 46b. The pad region 46a may contact the third transparent electrode 45 through the opening 47b, and the extension portion 46b may contact the third transparent electrode 46 through the opening 47c. The third current distribution layer 46 and the third ohmic electrode 48 may include the same material, such as metal.

[0237] A planarization layer or a first bonding layer 49 is formed on the third current distribution layer 46 and the third ohmic electrode 48. The first bonding layer 49 may be formed of light-transmitting SOG.

[0238] Reference Fig. 6A and Figure 6B ,Will Figure 3A and Figure 3B The first LED stack 23 is bonded to the carrier substrate 51. The first LED stack 23 may be bonded to the carrier substrate 51 through the adhesive layer 53. Specifically, the protective layer 29 may be disposed to face the carrier substrate 51. Then, the substrate 21 is removed from the first LED stack 23. In this way, the first conductive semiconductor layer 23a is exposed. In order to improve light extraction efficiency, the surface of the exposed first conductive semiconductor layer 23a may be textured.

[0239] Hereinafter, a process of manufacturing a light emitting device by combining the first LED stack 23 , the second LED stack 33 , and the third LED stack 43 manufactured by the above process with each other and patterning the first LED stack 23 , the second LED stack 33 , and the third LED stack 43 will be described.

[0240] Reference Fig. 7A and Figure 7B ,Will Figure 4A and Figure 4B The second LED stack 33 is bonded to Figure 5A and Figure 5B On the third LED stack 43.

[0241] The first bonding layer 49 and the planarizing layer 39 are disposed to face each other to align the third current distribution layer 46 and the 2-1st current distribution layer 36. Specifically, the central portion of the pad region 36a of the 2-1st current distribution layer 36 is aligned over the pad region 46a of the third current distribution layer 46.

[0242] Then, the second substrate 31 is removed from the second LED stack 33 by a technique such as laser lift-off, chemical lift-off, etc. In this way, the first conductive semiconductor layer 33a of the second LED stack 33 is exposed from above. In some exemplary embodiments, the surface of the exposed first conductive semiconductor layer 33a may be textured.

[0243] Reference Fig. 8A and Figure 8B , a second color filter 67 is formed on the exposed first conductive type semiconductor layer 33a. Figure 2A and Figure 2B The described second color filter 67 is substantially the same, so a detailed description thereof will be omitted to avoid redundancy.

[0244] Then, the second color filter 67 may be patterned to form an opening exposing the second LED stack 33, and a 2-2 current distribution layer 38 may be formed on the second color filter 67. The 2-2 current distribution layer 38 is formed to correspond to each light emitting device region, and includes a pad region 38a and an extension portion 38b extending from the pad region 38a. The specific shape of the extension portion 38b is not particularly limited, and may have various shapes for current distribution in the second LED stack 33.

[0245] Then, the second bonding layer 69 covers the 2-2 current distribution layer 38 and the second color filter 67. The second bonding layer 69 may be a light-transmitting organic layer or an inorganic layer. In this way, a flat surface may be provided on the upper surface of the second LED stack 33.

[0246] Then, refer to Fig.9A and Fig. 9B ,Will Fig. 6A and Figure 6B The first LED stack 23 is bonded to the second LED stack 33. The exposed first conductive type semiconductor layer 23a of the first LED stack 23 may be bonded to the second bonding layer 69. Optionally, another planarization layer may be additionally formed on the first conductive type semiconductor layer 23a, and the another planarization layer and the second bonding layer 69 may be bonded to each other.

[0247] Then, the carrier substrate 51 and the adhesive layer 53 are removed. In this way, the protective layer 29 and the first ohmic electrode 28 may be exposed.

[0248] Reference Fig. 10A and Fig. 10B , the protection layer 29 and the insulating layer 25 may be patterned so that the first LED stack 23 is exposed around the first reflective electrode 26, and then the first LED stack 23 and the second bonding layer 69 may be sequentially patterned so that the 2-2 current distribution layer 38 is exposed. In addition, the second color filter 67 may be exposed around the first reflective electrode 26. The pad region 38a and the extension portion 36b of the 2-2 current distribution layer 38 may be partially exposed.

[0249] Meanwhile, a portion of the first conductive type semiconductor layer 23 a on which the first ohmic electrode 28 is disposed at one corner of the light emitting device region may remain.

[0250] Reference Fig.11A and Fig. 11B , the second color filter 67, the second LED stack 33, the second transparent electrode 35, the planarization layer 39, and the first bonding layer 49 may be sequentially patterned so that the third current distribution layer 46 and the third ohmic electrode 48 are exposed. In addition, the pad region 36a of the 2-1st current distribution layer 36 is exposed, and a through hole penetrating the central portion of the pad region 36a is formed.

[0251] A through hole exposing the third current distribution layer 46 and the third ohmic electrode 48 may be formed. The second color filter 67, the second LED stack 33, the second transparent electrode 35, the planarization layer 39, and the first bonding layer 49 may be sequentially removed in the edge portion of the light emitting device region, and the third transparent electrode 45 and the third LED stack 43 may be removed so that the upper surface of the substrate 41 may be exposed. The exposed region of the substrate 41 may be a cutting region for cutting the substrate 41 into a plurality of light emitting devices.

[0252] Although the third current distribution layer 46 and the third ohmic electrode 48 are described as being exposed through the through hole, in some exemplary embodiments, the second color filter 67, the second LED stack 33, the second transparent electrode 35, the planarization layer 39 and the first bonding layer 49 arranged around the first reflective electrode 26 can be sequentially removed, and thus the third current distribution layer 46 and the third ohmic electrode 48 can be arranged adjacent to the side surface of the second LED stack 33.

[0253] Reference Fig. 12A and Fig. 12B , an upper insulating layer 71 is formed to cover the side surfaces and upper regions of the first LED stack 23, the second LED stack 33, and the third LED stack 43. The upper insulating layer 71 may be formed of a single layer or multiple layers of SiO2, Si3N4, SOG, etc. Optionally, the upper insulating layer 71 may include a distributed Bragg reflector formed by alternately depositing SiO2 and TiO2.

[0254] Then, the upper insulating layer 71 is patterned using photolithography and etching techniques to form openings 71a, 71b, 71c, 71d, and 71e. The opening 71a exposes the third current distribution layer 46 and the 2-1st current distribution layer 36. The opening 71b exposes the first reflective electrode 26. The opening 71a and the opening 71b may be disposed adjacent to each other. In addition, the first reflective electrode 26 may be exposed through a plurality of openings 71.

[0255] The opening 71 c exposes the first ohmic electrode 28 , the opening 71 d exposes the 2 - 2 current distribution layer 38 , and the opening 71 e exposes the third ohmic electrode 48 .

[0256] The upper insulating layer 71 may be removed at the edge of the light emitting device region. In this way, the upper surface of the substrate 41 may be exposed in the cutting region.

[0257] Reference Fig.13A and Fig. 13B , electrode pads 81a, 81b, 81c, and 81d are formed on the upper insulating layer 71. The electrode pads 81a, 81b, 81c, and 81d include a first electrode pad 81a, a second electrode pad 81b, a third electrode pad 81c, and a common electrode pad 81d.

[0258] The common electrode pad 81d is connected to the 2-1st current distribution layer 36 and the third current distribution layer 46 through the opening 71a, and is connected to the first reflective electrode 26 through the opening 71b. In this way, the common electrode pad 81d is electrically connected to the anode of the first LED stack 23, the anode of the second LED stack 33, and the anode of the third LED stack 43 in common.

[0259] The first electrode pad 81a is connected to the first ohmic electrode 28 through the opening 71c to be electrically connected to the cathode of the first LED stack 23, for example, the first conductive semiconductor layer 23a. The second electrode pad 81b is connected to the 2-2 current distribution layer 38 through the opening 71d to be electrically connected to the cathode of the second LED stack 33, for example, the first conductive semiconductor layer 33a, and the third electrode pad 81c is connected to the third ohmic electrode 48 through the opening 71e to be electrically connected to the cathode of the third LED stack 43, for example, the first conductive semiconductor layer 43a.

[0260] The electrode pads 81 a , 81 b , 81 c , and 81 d are electrically isolated from each other so that each of the first LED stack 23 , the second LED stack 33 , and the third LED stack 43 is electrically connected to two electrode pads to be independently driven.

[0261] Then, the light emitting device 100 may be formed by dividing the substrate 41 into a plurality of light emitting device regions. Fig.13AAs shown, electrode pads 81a, 81b, 81c, and 81d may be disposed at four corners of each light emitting device 100. In addition, the electrode pads 81a, 81b, 81c, and 81d may have a substantially rectangular shape, but the inventive concept is not limited thereto.

[0262] Although the substrate 41 is described as being divided, in some exemplary embodiments, the substrate 41 may be removed, and thus the surface of the exposed first conductive type semiconductor layer 43a may be textured. The substrate 41 may be removed after the first LED stack 23 is bonded to the second LED stack 33, or may be removed after the electrode pads 81a, 81b, 81c, and 81d are formed.

[0263] According to an exemplary embodiment, the light emitting device includes a first LED stack 23, a second LED stack 33, and a third LED stack 43, wherein the anodes of the LED stacks are electrically connected in common, and the cathodes of the LED stacks are independently connected. However, the inventive concept is not limited thereto, and the anodes of the first LED stack 23, the anodes of the second LED stack 33, and the anodes of the third LED stack 43 may be independently connected to the electrode pads, and the cathodes of the first LED stack 23, the cathodes of the second LED stack 33, and the cathodes of the third LED stack 43 may be electrically connected in common.

[0264] The light emitting device 100 may include a first LED stack 23 emitting red light, a second LED stack 33 emitting green light, and a third LED stack 43 emitting blue light, and thus may be used as a single pixel in a display device. Figure 1 As described, a display device can be provided by arranging a plurality of light emitting devices 100 on a circuit board 101. Since the light emitting device 100 includes a first LED stack 23, a second LED stack 33, and a third LED stack 43, the area of ​​a sub-pixel in one pixel can be increased. In addition, the first LED stack 23, the second LED stack 33, and the third LED stack 43 can be installed by installing one light emitting device 100, thereby reducing the number of installation processes.

[0265] As reference Figure 1 As described, the light emitting device 100 mounted on the circuit board 101 may be driven by a passive matrix method or an active matrix method.

[0266] Fig.14 is a schematic plan view of a display device according to an exemplary embodiment.

[0267] Reference Fig.14 , the display device includes a circuit board 201 and a plurality of light emitting devices 200 .

[0268] The circuit board 201 may include a circuit for passive matrix driving or active matrix driving. In an exemplary embodiment, the circuit board 201 may include wiring and resistors disposed therein. In another exemplary embodiment, the circuit board 201 may include wiring, transistors, and capacitors. The circuit board 201 may have pads disposed on its upper surface to allow electrical connection to the circuit disposed therein.

[0269] A plurality of light emitting devices 200 are arranged on a circuit board 201. Each light emitting device 200 may constitute a pixel. The light emitting device 200 has bump pads 251a, 251b, 251c, and 251d, and the bump pads 251a, 251b, 251c, and 251d are electrically connected to the circuit board 201. The light emitting devices 200 are arranged on the circuit board 201 as separate chips and are spaced apart from each other. The upper surface of each light emitting device 200 may be the surface of the LED stack 243, for example, the surface of the n-type semiconductor layer. In addition, the surface of the LED stack 243 may include a roughened surface formed by surface texturing. However, in some exemplary embodiments, the surface of the LED stack 243 may be covered with a light-transmitting insulating layer.

[0270] Will refer to Fig.15A and Fig. 15B The specific configuration of the light emitting device 200 is described in detail. Fig.27A and Fig.27B Light emitting device 2000 or Fig.36A and Fig.36B The light emitting device 2001 may also be arranged on the circuit board 201 instead of the light emitting device 200 .

[0271] Fig.15A is a schematic plan view of a light emitting device 200 according to an exemplary embodiment, Fig. 15B It is along Fig.15A A cross-sectional view taken along line AB.

[0272] Reference Fig.15A and Fig. 15B The light emitting device 200 may include bump pads 251a, 251b, 251c and 251d, a filler 253, a first LED stack 223, a second LED stack 233, a third LED stack 243, insulating layers 225, 229, 261 and 271, a first reflective electrode 226, a second transparent electrode 235, a third transparent electrode 245, a first ohmic electrode 228a, a second ohmic electrode 238 and a third ohmic electrode 248, connecting pads 228b and 228c, a second current spreading layer 236, a third current spreading layer 246, a first color filter 237, a second color filter 247, a first bonding layer 239, a second bonding layer 269, and connectors 268b, 268c, 268d, 278c and 278d.

[0273] Bump pads (or electrode pads) 251a, 251b, 251c and 251d and filler 253 are disposed below the first LED stack 223 and support the first LED stack 223, the second LED stack 233 and the third LED stack 243. Bump pads 251a, 251b, 251c and 251d may include metals such as copper (Cu), titanium (Ti), nickel (Ni), tantalum (Ta), platinum (Pt), palladium (Pd), chromium (Cr), etc. In some exemplary embodiments, a multi-layer solder barrier layer may be formed on the upper surface of the bump pad, and a gold (Au) or silver (Ag) surface layer may be disposed on the surface of the bump pad to improve solder wettability. Filler 253 is formed of an insulating material. Because bump pads 251a, 251b, 251c and 251d and filler 253 can be used as a support structure, a separate support substrate may be omitted. The electrical connection of the bump pads 251a, 251b, 251c, and 251d will be described in detail below.

[0274] The LED stacks are disposed on the bump pads 251a, 251b, 251c, and 251d in the order of the first LED stack 223, the second LED stack 233, and the third LED stack 243. The first LED stack 223, the second LED stack 233, and the third LED stack 243 may be sequentially stacked on top of each other, and thus the light emitting device 200 has a single chip structure of a single pixel.

[0275] The first LED stack 223, the second LED stack 233, and the third LED stack 243 include first conductive semiconductor layers 223a, 233a, and 243a, second conductive semiconductor layers 223b, 233b, and 243b, and an active layer between the first conductive semiconductor layers 223a, 233a, and 243a and the second conductive semiconductor layers 223b, 233b, and 243b, respectively. Specifically, the active layer may have a multi-quantum well structure. As shown in the figure, the second conductive semiconductor layers 223b, 233b, and 243b are respectively arranged below some regions of the first conductive semiconductor layers 223a, 233a, and 243a, and therefore, the lower surfaces of the first conductive semiconductor layers 223a, 233a, and 243a may be partially exposed.

[0276] The first LED stack 223, the second LED stack 233, and the third LED stack 243 may emit light of longer wavelengths as they are arranged closer to the bump pads 251a, 251b, 251c, and 251d. For example, the first LED stack 223 may be an inorganic light emitting diode that emits red light, the second LED stack 233 may be an inorganic light emitting diode that emits green light, and the third LED stack 243 may be an inorganic light emitting diode that emits blue light. The first LED stack 223 may include a well layer based on GaInP, and the second LED stack 233 and the third LED stack 243 may include a well layer based on GaInN. However, the inventive concept is not limited thereto. When the light emitting device 200 includes a micro-LED having a surface area of ​​less than about 10,000 square microns as known in the art, or a surface area of ​​less than about 4,000 square microns or 2,500 square microns in other exemplary embodiments, the first LED stack 223 can emit any one of red, green, and blue light, and the second LED stack 233 and the third LED stack 243 can emit different ones of red, green, and blue light without negatively affecting operation due to the small form factor of the micro-LED.

[0277] Since the wavelength of light emitted by the first LED stack 223 may be longer than the wavelength of light emitted by the second LED stack 233 and the third LED stack 243, light generated in the first LED stack 223 may be emitted to the outside through the second LED stack 233, the third LED stack 243, and the substrate 241. In addition, since the wavelength of light emitted by the second LED stack 233 may be longer than the wavelength of light emitted by the third LED stack 243, light generated in the second LED stack 233 may be emitted to the outside through the third LED stack 243 and the substrate 241.

[0278] In addition, the first conductive semiconductor layers 223a, 233a, and 243a of each LED stack 223, 233, and 243 may be n-type semiconductor layers, and the second conductive semiconductor layers 223b, 233b, and 243b of each LED stack 223, 233, and 243 may be p-type semiconductor layers. In the illustrated exemplary embodiment, the upper surface of the first LED stack 223 is an n-type semiconductor layer 223b, the upper surface of the second LED stack 233 is an n-type semiconductor layer 233a, and the upper surface of the third LED stack 243 is an n-type semiconductor layer 243b. In an exemplary embodiment, the first LED stack 223, the second LED stack 233, and the third LED stack 243 may have first conductive semiconductor layers 223a, 233a, and 243a having textured surfaces, respectively, to improve light extraction efficiency. However, when the second LED stack 233 emits green light, since green light has higher visibility than red light or blue light, it is preferable to make the luminous efficiency of the first LED stack 223 and the third LED stack 243 higher than that of the second LED stack 233. In this way, the luminous intensities of red light, green light, and blue light can be adjusted to be substantially uniform by applying surface texturing to a greater extent in the first LED stack 223 and the third LED stack 243 than in the second LED stack 233.

[0279] The insulating layer 225 is disposed below the first LED stack 223 and has at least one opening exposing the second conductive type semiconductor layer 223b of the first LED stack 223. The insulating layer 225 may have a plurality of openings widely distributed above the first LED stack 223. The insulating layer 225 may be a transparent insulating layer having a lower refractive index than the first LED stack 223.

[0280] The first reflective electrode 226 makes ohmic contact with the second conductive semiconductor layer 223b of the first LED stack 223 and reflects light generated in the first LED stack 223 toward the second LED stack 233. The first reflective electrode 226 is disposed on the insulating layer 225 and connected to the first LED stack 223 through an opening of the insulating layer 225.

[0281] The first reflective electrode 226 may include an ohmic contact layer 226a and a reflective layer 226b. The ohmic contact layer 226a is partially in contact with the second conductive semiconductor layer 223b (e.g., a p-type semiconductor layer). The ohmic contact layer 226a may be formed with a limited area to prevent light from being absorbed by the ohmic contact layer 226a. The ohmic contact layer 226a may be formed on the second conductive semiconductor layer 223b exposed in the opening of the insulating layer 225. The ohmic contact layers 226a spaced apart from each other are formed in a plurality of regions on the first LED stack 223 to facilitate current distribution in the second conductive semiconductor layer 223b. The ohmic contact layer 226a may be formed of a transparent conductive oxide or an Au alloy such as Au(Zn) or Au(Be).

[0282] The reflective layer 226b covers the ohmic contact layer 226a and the insulating layer 225. The reflective layer 226b covers the insulating layer 225, so that an omni-directional reflector can be formed by a stacked structure of the first LED stack 223 having a relatively high refractive index and the insulating layer 225 and the reflective layer 226b having a relatively low refractive index. The reflective layer 226b may include a reflective metal layer, such as Al, Ag, or Au. In addition, the reflective layer 226b may include an adhesive metal layer, such as Ti, Ta, Ni, or Cr, located on the upper and lower surfaces of the reflective metal layer to improve the adhesion of the reflective metal layer. Au may be particularly suitable for forming the reflective layer 226b in the first LED stack 223 due to its high reflectivity for red light and low reflectivity for blue or green light. The reflective layer 226b may cover 50% or more of the area of ​​the first LED stack 223, and in some exemplary embodiments, may cover most of the area of ​​the first LED stack 223 to improve light efficiency.

[0283] The reflective layer 226b may be formed of a metal layer having high reflectivity for light (e.g., red light) generated in the first LED stack 223. The reflective layer 226b may have relatively low reflectivity for light (e.g., green light or blue light) generated in the second LED stack 233 and the third LED stack 243. Therefore, the reflective layer 226b may absorb light generated in the second LED stack 233 and the third LED stack 243 and incident on the reflective layer 226b to reduce light interference.

[0284] The first ohmic electrode 228a is disposed on the exposed first conductive type semiconductor layer 223a and is in ohmic contact with the first conductive type semiconductor layer 223a. Fig. 15B As shown, the first ohmic electrode 228a may be disposed between the first conductive semiconductor layer 223a and the first bump pad 251a. The first ohmic electrode 228a may also be formed of a metal layer including Au.

[0285] The connection pads 228b and 228c may be formed together when forming the first reflective electrode 226, but the inventive concept is not limited thereto. For example, the connection pads 228b and 228c may be formed together when forming the first ohmic electrode 228a, or by a separate process from the above process.

[0286] The connection pads 228 b and 228 c are electrically insulated from the first reflective electrode 226 and the first ohmic electrode 228 a. For example, the connection pads 228 b and 228 c may be disposed under the insulating layer 225 and insulated from the first LED stack 223 .

[0287] The insulating layer 229 covers the first reflective electrode 226 to isolate the first reflective electrode 226 from the bump pads 251a, 251b, 251c and 251d. The insulating layer 229 includes openings 229a, 229b, 229c and 229d. The opening 229a exposes the first ohmic electrode 228a, the opening 229b exposes the connection pad 228b, the opening 229c exposes the connection pad 29c, and the opening 229d exposes the first reflective electrode 226.

[0288] The material of the insulating layer 229 may be SiO 2 , Si 3 N 4 , SOG, etc., but is not limited thereto, and may include a material that transmits light or a material that does not transmit light.

[0289] The second transparent electrode 235 is in ohmic contact with the second conductive semiconductor layer 233b of the second LED stack 233. As shown in the figure, the second transparent electrode 235 is in contact with the lower surface of the second LED stack 233 between the first LED stack 223 and the second LED stack 233. The second transparent electrode 235 can be formed of a metal layer or a conductive oxide layer that is transparent to red light. The second transparent electrode 235 can also be transparent to green light.

[0290] The third transparent electrode 245 is in ohmic contact with the second conductive semiconductor layer 243b of the third LED stack 243. The third transparent electrode 245 may be disposed between the second LED stack 233 and the third LED stack 243 and in contact with the lower surface of the third LED stack 243. The third transparent electrode 245 may be formed of a metal layer or a conductive oxide layer that is transparent to red and green light. The third transparent electrode 245 may also be transparent to blue light. The second transparent electrode 235 and the third transparent electrode 245 may be in ohmic contact with the p-type semiconductor layer of each LED stack to facilitate current distribution. Examples of the conductive oxide layer for the second transparent electrode 235 and the third transparent electrode 245 may include SnO2, InO2, ITO, ZnO, IZO, and the like.

[0291] The first color filter 237 may be disposed between the second transparent electrode 235 and the first LED stack 223, and the second color filter 247 may be disposed between the second LED stack 233 and the third LED stack 243. The first color filter 237 transmits light generated in the first LED stack 223, and reflects light generated in the second LED stack 233. The second color filter 247 transmits light generated in the first LED stack 223 and the second LED stack 233, and reflects light generated in the third LED stack 243. Therefore, light generated in the first LED stack 223 may be emitted to the outside through the second LED stack 233 and the third LED stack 243, and light generated in the second LED stack 233 may be emitted to the outside through the third LED stack 243. In addition, light generated in the second LED stack 233 may be prevented from being lost due to incident on the first LED stack 223, or light generated in the third LED stack 243 may be prevented from being lost due to incident on the second LED stack 233.

[0292] In some exemplary embodiments, the first color filter 237 may also reflect light generated in the third LED stack 243 .

[0293] The first color filter 237 and the second color filter 247 can be, for example, a low-pass filter that only passes a low frequency range (i.e., a long wave band), a band-pass filter that only passes a predetermined wave band, or a band-stop filter that only blocks a predetermined wave band. Specifically, the first color filter 237 and the second color filter 247 can be formed by alternately stacking insulating layers with different refractive indices from each other, and can be formed, for example, by alternately stacking TiO2 and SiO2 insulating layers, Ta2O5 and SiO2 insulating layers, Nb2O5 and SiO2 insulating layers, HfO2 and SiO2 insulating layers, or ZrO2 and SiO2 insulating layers. Specifically, the first color filter 237 and the second color filter 247 can include a distributed Bragg reflector (DBR). The stop band of the distributed Bragg reflector can be controlled by adjusting the thickness of TiO2 and SiO2. The low-pass filter and the band-pass filter can also be formed by alternately stacking insulating layers with different refractive indices from each other.

[0294] The second current spreading layer 236 may be electrically connected to the second conductive semiconductor layer 233b of the second LED stack 233 through the second transparent electrode 235. The second current spreading layer 236 may be disposed on a lower surface of the first color filter 237 and connected to the second transparent electrode 235 through the first color filter 237. The first color filter 237 may have an opening exposing the second LED stack 233, and the second current spreading layer 236 may be connected to the second transparent electrode 235 through the opening of the first color filter 237.

[0295] The second current spreading layer 236 may include a pad region 236a and an extension portion 236b extending from the pad region 236a (see Fig.17A and Fig. 17B ). In addition, the pad region 236a may have a substantially annular shape including a hollow portion. Fig.17A The extending portion 236 b is shown extending in a diagonal direction of the light emitting device 200 , but the inventive concept is not limited thereto and the extending portion 236 b may have various shapes.

[0296] The second current spreading layer 236 is formed of a metal layer having a lower sheet resistance than the second transparent electrode 235, and thus contributes to current distribution in the second LED stack 233. In addition, the second current spreading layer 236 is disposed below the first color filter 237 so that the first color filter 237 reflects light generated in the second LED stack 233 and traveling toward the second current spreading layer 236 to prevent light loss.

[0297] The second ohmic electrode 238 makes ohmic contact with the exposed lower surface of the first conductive type semiconductor layer 233a. The second ohmic electrode 238 may have a substantially annular shape including a hollow portion (see Fig.17A In some exemplary embodiments, the second ohmic electrode 238 may include an extension portion for current distribution and a pad region. The first color filter 237 may surround the second ohmic electrode 238 and cover the first conductive type semiconductor layer 233 a.

[0298] The third current spreading layer 246 may be electrically connected to the second conductive semiconductor layer 243b of the third LED stack 243 through the third transparent electrode 245. The third current spreading layer 246 may be disposed on a lower surface of the second color filter 247 and connected to the third transparent electrode 245 through the second color filter 247. The second color filter 247 may have an opening exposing the third LED stack 243, and the third current spreading layer 246 may be connected to the third transparent electrode 245 through the opening of the second color filter 247.

[0299] The third current spreading layer 246 may include a pad region 246a and an extension portion 246b extending from the pad region 246a (see Fig.18A and Fig.18B ). In addition, the pad region 246a may have a substantially annular shape including a hollow portion. Fig.18A It is shown that the extension portion 246 b extends along the edge of one side of the light emitting device 200 , but the inventive concept is not limited thereto, and the extension portion 246 b may have various shapes.

[0300] The third current spreading layer 246 is formed of a metal layer having a lower sheet resistance than the third transparent electrode 245, and thus contributes to current distribution in the third LED stack 243. The third current spreading layer 246 is disposed under the second color filter 247 so that the second color filter 247 reflects light generated in the third LED stack 243 and traveling toward the third current spreading layer 246 to prevent light loss.

[0301] The third ohmic electrode 248 is in ohmic contact with the exposed lower surface of the first conductive type semiconductor layer 243a. The third ohmic electrode 248 may have a substantially annular shape including a hollow portion. In some exemplary embodiments, the third ohmic electrode 248 may include an extension portion for current distribution and a pad area. The second color filter 247 may surround the third ohmic electrode 248 and cover the first conductive type semiconductor layer 243a.

[0302] The first bonding layer 239 bonds the second LED stack 233 to the first LED stack 223. The first bonding layer 239 can bond the first LED stack 223 and the first color filter 238 to each other. The first bonding layer 239 may be formed of a transparent organic layer, or may be formed of a transparent inorganic layer. Examples of the organic layer may include SU8, poly(methyl methacrylate) (PMMA), polyimide, polyparaxylene, benzocyclobutene (BCB), etc., and examples of the inorganic layer may include Al2O3, SiO2, SiN x etc. The organic layer may be joined under high vacuum and high pressure, and the inorganic layer may be joined under high vacuum while adjusting the surface energy by using plasma or the like after the surface is planarized by, for example, a chemical mechanical polishing process.

[0303] The second bonding layer 269 bonds the third LED stack 243 to the second LED stack 233. As shown in the figure, the second bonding layer 269 can bond the second LED stack 233 and the second color filter 247 to each other. The second bonding layer 269 can contact the second LED stack 233, but is not limited thereto. As shown in the figure, an insulating layer can be provided on the second LED stack 233, and the second bonding layer 269 can also contact the insulating layer 261. The second bonding layer 269 can be formed of a transparent organic layer or a transparent inorganic layer.

[0304] Bump pads 251a, 251b, 251c, and 251d may be disposed under the insulating layer 229. The bump pads 251a, 251b, 251c, and 251d include a first bump pad 251a, a second bump pad 251b, a third bump pad 251c, and a common bump pad 251d.

[0305] The first bump pad 251a is electrically connected to the first conductive type semiconductor layer 223a of the first LED stack 223. The first bump pad 251a may be connected to the first ohmic electrode 228a through the opening 229a.

[0306] The second bump pad 251b is electrically connected to the first conductive type semiconductor layer 233a of the second LED stack 233. The second bump pad 251b may be connected to the connection pad 228b through the opening 229b.

[0307] The third bump pad 251c is electrically connected to the first conductive type semiconductor layer 243a of the third LED stack 243. The third bump pad 251c may be connected to the connection pad 228c through the opening 229c.

[0308] The common connection pad 251d is electrically connected to the second conductive semiconductor layers 223a of the first LED stack 223, the second LED stack 233, and the third LED stack 243. The common connection pad 251d may be connected to the first reflective electrode 226 through the opening 229d.

[0309] Connectors 268 b , 268 c , 268 d , 278 c , and 278 d are provided to electrically connect the second LED stack 233 and the third LED stack 243 to the bump pads 251 b , 251 c , and 251 d .

[0310] The second connector 268b electrically connects the first conductive semiconductor layer 233a of the second LED stack 233 to the second bump pad 251b. The second connector 268b may be connected to the upper surface of the second ohmic electrode 238 and the connecting pad 228b. The second connector 268b and the second bump pad 251b may be arranged above and below the connecting pad 228b, while the connecting pad 228b is interposed between the second connector 268b and the second bump pad 251b to electrically connect the second connector 268b and the second bump pad 251b to each other through the connecting pad 228b. However, the inventive concept is not limited thereto. For example, the connecting pad 28 may be omitted, and the second connector 268b may be directly connected to the second bump pad 251b. However, the second bump pad 251b and the second connector 268b may be formed by separate processes and may include materials different from each other.

[0311] The second connection member 268b may penetrate the first conductive type semiconductor layer 233a of the second LED stack 233 and may contact the first conductive type semiconductor layer 233a. The second connection member 268b is spaced apart from the second conductive type semiconductor layer 233b and is insulated from the first LED stack 223. To this end, the insulating layer 261 may cover the sidewall of the through hole in which the second connection member 268b is formed.

[0312] The third connector electrically connects the first conductive type semiconductor layer 243a of the third LED stack 243 to the third bump pad 251c. The third connector may include a 3-1st connector 268c and a 3-2nd connector 278c.

[0313] The 3-1st connection member 268c may penetrate the first LED stack 223 and the second LED stack 233 and may be connected to the connection pad 228c. The 3-1st connection member 268c is insulated from the first LED stack 223 and the second LED stack 233, and for this purpose, the insulating layer 261 insulates the 3-1st connection member 268c from the first LED stack 223 and the second LED stack 233.

[0314] According to an exemplary embodiment, the 3-1 th connection member 268 c may include a pad region on the second LED stack 233 .

[0315] The 3-2nd connection member 278c may penetrate the first conductive semiconductor layer 243a of the third LED stack 243 to be connected to the third ohmic electrode 248 and the pad region of the 3-1st connection member 268c. The 3-2nd connection member 278c may contact the upper surface of the third ohmic electrode 248 and contact the first conductive semiconductor layer 243a.

[0316] The common connectors 268 d and 278 d electrically connect the second conductive type semiconductor layer 233 b of the second LED stack 233 and the second conductive type semiconductor layer 243 b of the third LED stack 243 to the common bump pad 251 d .

[0317] The first common connector 268d may be connected to the second transparent electrode 245 and the first reflective electrode 226, and thus electrically connected to the common bump pad 251d. The first common connector 268d may penetrate the second current diffusion layer 236. For example, when the second current diffusion layer 236 includes a hollow portion, the first common connector 268d may pass through the hollow portion of the second current diffusion layer 236. In the illustrated exemplary embodiment, the first common connector 268d is connected to the second transparent electrode 235 and is spaced apart from the second current diffusion layer 236, but may also be electrically connected to the second current diffusion layer 236 through the second transparent electrode 235. In some exemplary embodiments, the first common connector 268d may be directly connected to the second current diffusion layer 236. For example, the upper surface of the second current diffusion layer 236 may be exposed through the second transparent electrode 235 and the first color filter 237, and the first common connector 268d may be connected to the exposed upper surface of the second current diffusion layer 236.

[0318] The first common connector 268d may include a pad region to which the second common connector 278d may be connected. The pad region of the first common connector 268d may be disposed on the first conductive semiconductor layer 233a of the second LED stack 233. However, since the first common connector 268d needs to be insulated from the first conductive semiconductor layer 233a, the insulating layer 261 may be interposed between the first common connector 268d and the first conductive semiconductor layer 233a.

[0319] The second common connection 278d may be connected to the third transparent electrode 245 and the first common connection 268d. The second common connection 278d may penetrate the third LED stack 243 to be connected to the third transparent electrode 245, and thus may be connected to the upper surface of the third transparent electrode 245. The second common connection 278d is insulated from the first conductive type semiconductor layer 243a, and for this purpose, the insulating layer 271 may be interposed between the second common connection 278d and the first conductive type semiconductor layer 243a.

[0320] The second common connector 278d may penetrate the third current spreading layer 246. For example, when the third current spreading layer 246 includes a hollow portion, the second common connector 278d may pass through the hollow portion of the third current spreading layer 246. In the illustrated exemplary embodiment, the second common connector 278d is connected to the third transparent electrode 245 and is spaced apart from the third current spreading layer 246, but is also electrically connected to the third current spreading layer 246 through the third transparent electrode 245. In some exemplary embodiments, the second common connector 278d may be directly connected to the third current spreading layer 246. For example, the upper surface of the third current spreading layer 246 may be exposed through the third transparent electrode 245 and the second color filter 247, and the second common connector 278d may be directly connected to the exposed upper surface of the third current spreading layer 246.

[0321] According to an exemplary embodiment, the first LED stack 223 is electrically connected to the bump pads 251d and 251a, the second LED stack 233 is electrically connected to the bump pads 251d and 251b, and the third LED stack 243 is electrically connected to the bump pads 251d and 251c. In this way, the anode of the first LED stack 223, the anode of the second LED stack 233, and the anode of the third LED stack 243 are electrically connected to the bump pad 251d, and the cathode of the first LED stack 223, the cathode of the second LED stack 233, and the cathode of the third LED stack 243 are electrically connected to the first bump pad 251a, the second bump pad 251b, and the third bump pad 251c, respectively. In this way, the first LED stack 223, the second LED stack 233, and the third LED stack 243 can be driven independently.

[0322] Fig.16A , Fig. 16B , Fig.17A , Fig. 17B , Fig.18A , Fig.18B , Fig.19A , Fig.19B , Fig. 20A , Fig. 20B , Fig.21A , Fig. 21B , Fig.22A , Fig. 22B , Fig.23A , Fig. 23B , Fig.24A , Fig. 24B , Fig.25A , Fig.25B , Fig.26A and Fig.26B 2 is a schematic plan view and a cross-sectional view showing a method of manufacturing a light emitting device 200 according to an exemplary embodiment. Fig.14, and each cross-sectional view is a cross-sectional view taken along a line shown in the corresponding plan view.

[0323] Reference Fig.16A and Fig. 16B , a first LED stack 223 is grown on a first substrate 221. The first substrate 221 may be, for example, a GaAs substrate. The first LED stack 223 may be formed of a semiconductor layer based on AlGaInP and include a first conductive type semiconductor layer 223a, an active layer, and a second conductive type semiconductor layer 223b. The first conductive type may be an n-type, and the second conductive type may be a p-type.

[0324] Next, the second conductive type semiconductor layer 223 b is partially removed to expose the first conductive type semiconductor layer 223 a .

[0325] An insulating layer 225 is formed on the first LED stack 223, and an opening may be formed by patterning the insulating layer 225. For example, SiO2 is formed on the first LED stack 223, a photoresist is applied to the SiO2, and then a photoresist pattern is formed using photolithography and development. Then, the SiO2 may be patterned using the photoresist pattern as an etching mask to form an opening.

[0326] Then, an ohmic contact layer 226a may be formed in each opening of the insulating layer 225. The ohmic contact layer 226a may be formed using a lift-off technique, etc. After the ohmic contact layer 226a is formed, a reflective layer 226b covering the ohmic contact layer 226a and the insulating layer 225 is formed. The reflective layer 226b may be formed of, for example, Au, and may be formed using a lift-off technique, etc. The first reflective electrode 226 is formed of the ohmic contact layer 226a and the reflective layer 226b.

[0327] As shown in the figure, the first reflective electrode 226 may have a shape in which three corners are removed from a rectangular light emitting device region. In addition, the ohmic contact layer 226a may be widely distributed at the lower portion of the first reflective electrode 226. Fig.16A One light emitting device region is shown, but a plurality of light emitting device regions may be provided on the substrate 221, and the first reflective electrode 226 may be formed in each light emitting device region.

[0328] A first ohmic electrode 228a is formed on the exposed first conductive type semiconductor layer 223a. The first ohmic electrode 228a is in ohmic contact with the first conductive type semiconductor layer 223a and is insulated from the second conductive type semiconductor layer 223b.

[0329] Connection pads 228b and 228c may be formed on the insulating layer 225. The connection pads 228b and 228c may be formed together with the reflective layer 226b or together with the first ohmic electrode 228a, but the inventive concept is not limited thereto and may be formed through a separate process.

[0330] An insulating layer 229 is formed on the first reflective layer 226, the first ohmic electrode 228a, and the connection pads 228c and 228d. The insulating layer 229 has openings 229a, 229b, 229c, and 229d that respectively expose the first ohmic electrode 228a, the connection pads 228c and 228d, and the first reflective electrode 226. The insulating layer 229 may be formed of, for example, SiO2, Si3N4, SOG, or the like.

[0331] Reference Fig.17A and Fig. 17B , a second LED stack 233 is grown on the second substrate 231, and a second transparent electrode 235 is formed on the second LED stack 233. The second LED stack 233 may be formed of a gallium nitride-based semiconductor layer, and may include a first conductive type semiconductor layer 233a, an active layer, and a second conductive type semiconductor layer 233b. The active layer may include a GaInN well layer. The first conductive type may be an n-type, and the second conductive type may be a p-type.

[0332] The second substrate 231 is a substrate on which a gallium nitride-based semiconductor layer may be grown, and may be different from the first substrate 221. The composition ratio of the GaInN well layer may be determined so that the second LED stack 233 may emit, for example, green light. The second transparent electrode 235 is in ohmic contact with the second conductive type semiconductor layer 233b.

[0333] The second transparent electrode 235 and the second conductive type semiconductor layer 233b are partially removed to expose the first conductive type semiconductor layer 233a. The exposed region of the first conductive type semiconductor layer 233a may be selected so as not to overlap with the exposed region of the first conductive type semiconductor layer 223a.

[0334] A first color filter 237 is formed on the second transparent electrode 235. The first color filter 237 may cover the exposed first conductive type semiconductor layer 233a. Fig.15A and Fig. 15B The described materials are substantially the same, so a detailed description thereof will be omitted to avoid redundancy.

[0335] The first color filter 237 is patterned to form an opening exposing the second transparent electrode 235 and an opening exposing the first conductive type semiconductor layer 233 a .

[0336] Then, a second current diffusion layer 236 is formed on the first color filter 237. The second current diffusion layer 236 is formed of a metal layer. The second current diffusion layer 236 may include a pad region 236a and an extension portion 236b. The pad region 236a may be formed to have a substantially annular shape and have a hollow portion exposing the first color filter 237 at its center. The extension portion 236b may extend from the pad region 236a and may be connected to the second transparent electrode 235 exposed through the opening of the first color filter 237. The extension portion 236b may extend substantially in a diagonal direction, but is not limited thereto. The extension portion 236b may have various shapes. Although Fig.17A One light emitting device region is shown, but a plurality of light emitting device regions may be provided on the substrate 231 , and the second current spreading layer 236 may be formed in each light emitting device region.

[0337] A second ohmic electrode 238 is formed on the first conductive semiconductor layer 233a. The second ohmic electrode 238 is in ohmic contact with the first conductive semiconductor layer 233a and may be formed of, for example, Ti / Al. A side surface of the second ohmic electrode 238 may be in contact with the first color filter 237, and thus, light may be prevented from leaking into a region between the second ohmic electrode 238 and the first color filter 237. The second ohmic electrode 238 and the second current diffusion layer 236 may also be formed together with each other through the same process, or may be formed through separate processes to include materials different from each other.

[0338] Reference Fig.18A and Fig.18B , a third LED stack 243 is grown on the third substrate 241, and a third transparent electrode 245 is formed on the third LED stack 243. The third LED stack 243 may be formed of a gallium nitride-based semiconductor layer, and may include a first conductive type semiconductor layer 243a, an active layer, and a second conductive type semiconductor layer 243b. The active layer may further include a GaInN well layer. The first conductive type may be an n-type, and the second conductive type may be a p-type.

[0339] The third substrate 241 is a substrate on which a gallium nitride-based semiconductor layer may be grown, and may be different from the first substrate 221. The composition ratio of GaInN may be determined so that the third LED stack 243 may emit, for example, blue light. The third transparent electrode 245 is in ohmic contact with the second conductive type semiconductor layer 243b.

[0340] The third transparent electrode 245 and the second conductive type semiconductor layer 243b are partially removed to expose the first conductive type semiconductor layer 243a. The exposed region of the first conductive type semiconductor layer 243a may be selected so as not to overlap with the exposed regions of the first conductive type semiconductor layers 223a and 233a.

[0341] A second color filter 247 is formed on the third transparent electrode 245. The second color filter 247 may also cover the exposed first conductive type semiconductor layer 243a. Fig.15A and Fig. 15B The described materials are substantially the same, so a detailed description thereof will be omitted to avoid redundancy.

[0342] The second color filter 247 may be patterned to form an opening exposing the third transparent electrode 245 and an opening exposing the first conductive type semiconductor layer 243 a .

[0343] Then, a third current diffusion layer 246 is formed on the second color filter 247. The third current diffusion layer 246 is formed of a metal layer. The third current diffusion layer 246 may include a pad region 246a and an extension 246b. The pad region 246a may be formed to have a substantially annular shape and have a hollow portion exposing the second color filter 247 at its center. By forming a hollow portion in the third current diffusion layer 245 in advance, the process of patterning the third current diffusion layer 246 may be omitted in a subsequent process to simplify the process of manufacturing the light emitting device 200. However, the inventive concept is not limited thereto, and the pad region 246a may be formed without a hollow portion, and a hollow portion may be formed by patterning the pad region 246a in a subsequent process.

[0344] The extension 246b may extend from the pad region 246a and may be connected to the third transparent electrode 245 exposed through the opening of the second color filter 247. As shown in the figure, the extension 246b may extend substantially along the edge, but is not limited thereto. The extension 246b may have various shapes. Although Fig.18A One light emitting device region is shown, but a plurality of light emitting device regions may be provided on the substrate 241 , and the third current spreading layer 246 may be formed in each light emitting device region.

[0345] A third ohmic electrode 248 is formed on the first conductive semiconductor layer 243a. The third ohmic electrode 248 is in ohmic contact with the first conductive semiconductor layer 243a and may be formed of, for example, Ti / Al. A side surface of the third ohmic electrode 248 may be in contact with the second color filter 247, and thus, light may be prevented from leaking into a region between the third ohmic electrode 248 and the second color filter 247. The third ohmic electrode 248 and the third current diffusion layer 246 may also be formed together with each other through the same process, or may be formed through separate processes to include materials different from each other.

[0346] Reference Fig.19A and Fig.19B ,exist Fig.16A and Fig. 16BBump pads 251a, 251b, 251c and 251d are formed on the first LED stack 223. Bump pads 251a, 251b, 251c and 251d are formed on the insulating layer 229. Bump pads 251a, 251b, 251c and 251d may include, for example, a solder barrier layer, a main body and a surface layer. The solder barrier layer may be formed of, for example, a single layer or multiple layers including at least one of Ti, Ni, Ta, Pt, Pd, Cr, etc., the main body may be formed of Cu, and the surface layer may be formed of Au or Ag. The surface layer may improve the wettability of the solder and facilitate the installation of the bump pads 251a, 251b, 251c and 251d, and the solder barrier layer may prevent the diffusion of metal materials such as Sn in the solder to improve the reliability of the light emitting device 200.

[0347] The first bump pad 251a is connected to the first ohmic electrode 228a through the opening 229a, the second bump pad 251b is connected to the connection pad 228b through the opening 229b, the third bump pad 251c is connected to the connection pad 228c through the opening 229c, and the common bump pad 251d is connected to the first reflective electrode 226 through the opening 229d.

[0348] Filler 253 may fill the area between bump pads 251a, 251b, 251c and 251d. Bump pads 251a, 251b, 251c and 251d are formed on substrate 221 for each light emitting device, and filler 253 fills the area between these bump pads 251a, 251b, 251c and 251d.

[0349] Reference Fig. 20A and Fig. 20B , and then remove the substrate 221 from the first LED stack 223 . Fig. 20B Shows Fig.19B . The bump pads 251a, 251b, 251c, and 251d and the filler 253 may be used as a support structure, and the substrate 221 may be removed from the first LED stack 223 by chemical etching or the like. Thus, the first conductive semiconductor layer 223a is exposed. In order to improve light extraction efficiency, the surface of the exposed first conductive semiconductor layer 223a may be textured.

[0350] Reference Fig.21A and Fig. 21B ,Will Fig.17A and Fig. 17B The second LED stack 233 is bonded to the first LED stack 223 . Bonding material layers are respectively formed on the first LED stack 223 and the first color filter 237 , and bonded to each other to form a first bonding layer 239 .

[0351] The second current spreading layer 236 and the bump pads 251b and 251d are bonded to each other to align with each other. Specifically, the central area of ​​the pad area 236a of the second current spreading layer 236 can be aligned to be positioned on the first reflective electrode 226, and the second ohmic electrode 238 can be aligned to be positioned on the connection pad 228b.

[0352] Then, the second substrate 231 is removed from the second LED stack 233 using a technique such as a laser lift-off technique, a chemical lift-off technique, etc. Thus, the first conductive semiconductor layer 233a of the second LED stack 233 is exposed from above. In some exemplary embodiments, the surface of the exposed first conductive semiconductor layer 233a is textured to form a roughened surface.

[0353] Reference Fig.22A and Fig. 22B , and then holes h1, h2, and h3 are formed that penetrate the second LED stack 233 and the first LED stack 223. The holes h1 and h2 may sequentially penetrate the second LED stack 233, the second transparent electrode 235, the first color filter 237, the first bonding layer 239, the first LED stack 223, and the insulating layer 225. When a hollow portion is not formed in the second current spreading layer 236, the second current spreading layer 236 is patterned when the hole h1 is formed, thereby forming a hollow portion. At the same time, the hole h1 may partially expose the upper surface of the second transparent electrode 235 and expose the upper surface of the first reflective electrode 226. Although Fig.22A and Fig. 22B It is shown that the upper surface of the second transparent electrode 235 is exposed by the hole h1, but the upper surface of the second current spreading layer 236 may also be exposed. The hole h2 exposes the upper surface of the connection pad 228c.

[0354] The hole h3 may penetrate the first conductive type semiconductor layer 233 a to expose the upper surface of the second ohmic electrode 238 , and may penetrate the first bonding layer 239 , the first LED stack 223 , and the insulating layer 225 to expose the connection pad 228 b .

[0355] Reference Fig.23A and Fig. 23B The insulating layer 261 may be formed to cover the sidewalls of the holes h1 , h2 , and h3 . The insulating layer 261 may also cover the upper surface of the second LED stack 233 .

[0356] Next, connectors 268b, 268c, and 268d are formed. Connector 268b connects the exposed second ohmic electrode 238 to connection pad 228b. Connector 268b connects the second ohmic electrode 238 and connection pad 228b. In addition, connector 268b may be connected to first conductive type semiconductor layer 233a. Connector 268b is electrically insulated from first LED stack 223 by insulating layer 261.

[0357] The connection member 268c is connected to the exposed connection pad 228c through the hole h2. The connection member 268c is electrically insulated from both the second LED stack 233 and the first LED stack 223 by the insulating layer 261. The connection member 268c may have a pad area located on the second LED stack 233.

[0358] The connector 268d is connected to the second transparent electrode 235 and the first reflective electrode 226 exposed by the hole h3, and electrically connects the second transparent electrode 235 and the first reflective electrode 226 to each other. The connector 268d is electrically insulated from the first conductive semiconductor layer 233a of the second LED stack 233 and the first conductive semiconductor layer 223a of the first LED stack 223. In another exemplary embodiment, the connector 268d may be connected to the second current spreading layer 236. The connector 268d may also include a pad region.

[0359] Reference Fig.24A and Fig. 24B ,Will Fig.18A and Fig.18B The third LED stack 243 is bonded to the second LED stack 233 .

[0360] A bonding material layer is formed on the second LED stack 233 on which the connectors 268b, 268c and 268d are formed, and another bonding material layer is formed on the second color filter 247. The second bonding layer 269 can be formed by bonding the bonding material layers to each other. In addition, the third substrate 241 can be removed from the third LED stack 243 using a technique such as a laser lift-off technique, a chemical lift-off technique, etc. Therefore, the first conductive semiconductor layer 243a can be exposed, and a surface roughened by surface texturing can be formed on the surface of the exposed first conductive semiconductor layer 243a.

[0361] The second bonding layer 269 may also contact the upper surface of the second LED stack 233 , but as shown, may also contact the insulating layer 261 .

[0362] Reference Fig.25A and Fig.25B , a hole is formed through the third LED stack 243 to expose the connectors 268c and 268d. The hole penetrates the second bonding layer 269. The upper surface of the third ohmic electrode 248 is exposed by the hole exposing the connector 268c, and the upper surface of the third transparent electrode 245 is partially exposed by the hole exposing the connector 268d. Although the upper surface of the third transparent electrode 245 is described as being exposed by the hole exposing the connector 268d, in some exemplary embodiments, the third transparent electrode 245 and the second color filter 247 may be removed, and the upper surface of the third current spreading layer 246 may also be exposed.

[0363] Reference Fig.26A and Fig.26B The insulating layer 271 may be formed to cover the sidewalls of the hole. The insulating layer 271 may also cover the upper surface of the third LED stack 243.

[0364] Next, connectors 278c and 278d are formed. The connector 278c connects the exposed third ohmic electrode 248 to the connector 268c. The connector 278c connects the third ohmic electrode 248 and the connector 268c to each other. In addition, the connector 278c may be connected to the first conductive type semiconductor layer 243a.

[0365] The connector 278d may be connected to the third transparent electrode 245 and the connector 268d. Thus, the second conductive semiconductor layer 243b of the third LED stack 243 is electrically connected to the common bump pad 251d. The connector 278d is electrically insulated from the first conductive semiconductor layer 243a by the insulating layer 271. The connector 278d may pass through the hollow portion of the third current spreading layer 246. In another exemplary embodiment, the upper surface of the third current spreading layer 246 may be exposed, and the connector 278d may be connected to the upper surface of the third current spreading layer 246.

[0366] Then, the light emitting device 200 is completed by dividing the substrate into light emitting device regions. Fig.26A As shown, bump pads 251a, 251b, 251c and 251d may be disposed at four corners of each light emitting device 200. In addition, bump pads 251a, 251b, 251c and 251d may have a substantially rectangular shape, but the inventive concept is not limited thereto. In some exemplary embodiments, an insulating layer covering the side surface of each light emitting device may be additionally formed. The insulating layer may include a distributed Bragg reflector, a transparent insulating film, or a reflective metal layer or an organic reflective layer of a multilayer structure formed thereon to reflect light, or may include a light absorbing layer such as a black epoxy resin to block light. In this way, light directed to the side surface from the first LED stack 223, the second LED stack 233, and the third LED stack 243 may be reflected or absorbed to prevent light interference between pixels. In addition, light directed to the side surface may be reflected using a reflective layer to improve light efficiency, and optionally, the contrast of the display device may be improved by blocking light using a light absorbing layer.

[0367] According to an exemplary embodiment, the light emitting device includes a first LED stack 223, a second LED stack 233, and a third LED stack 243, wherein an anode of the first LED stack 223, an anode of the second LED stack 233, and an anode of the third LED stack 243 are electrically connected in common, and a cathode of the first LED stack 223, a cathode of the second LED stack 233, and a cathode of the third LED stack 243 are independently connected. However, the inventive concept is not limited thereto, and the anode of the first LED stack 223, an anode of the second LED stack 233, and an anode of the third LED stack 243 may be independently connected to the bump pad, and the cathode of the first LED stack 223, a cathode of the second LED stack 233, and a cathode of the third LED stack 243 may be electrically connected in common.

[0368] The light emitting device 200 may include a first LED stack 223 emitting red light, a second LED stack 233 emitting green light, and a third LED stack 243 emitting blue light, and thus may be used as a single pixel in a display device. Fig.14 As described, a display device can be provided by arranging a plurality of light emitting devices 200 on a circuit board 201. Since the light emitting device 200 includes a first LED stack 223, a second LED stack 233, and a third LED stack 243, the area of ​​a sub-pixel in one pixel can be increased. In addition, the first LED stack 223, the second LED stack 233, and the third LED stack 243 can be installed by installing one light emitting device 200, thereby reducing the number of installation processes.

[0369] At the same time, as reference Fig.14 As described, the light emitting device 200 mounted on the circuit board 201 may be driven by a passive matrix method or an active matrix method.

[0370] Fig.27A and Fig.27B are schematic plan views and cross-sectional views of a light emitting device 2000 according to another exemplary embodiment.

[0371] Reference Fig.27A and Fig.27BAccording to the exemplary embodiment, the light emitting device 2000 may include bump pads 251a, 251b, 251c and 251d, a filler 253, a first LED stack 223, a second LED stack 233, a third LED stack 243, insulating layers 225, 229, 2161 and 2171, a first reflective electrode 226, a second transparent electrode 235, a third transparent electrode 245, a first ohmic electrode 228a, connecting pads 228b and 228c, a second current spreading layer 236, a third current spreading layer 246, a first color filter 237, a second color filter 247, a first bonding layer 2139, a second bonding layer 2169, and connectors 2168b, 2168c, 2168d, 2178c and 2178d.

[0372] The light emitting device 2000 according to the illustrated exemplary embodiment is substantially similar to the light emitting device 200 described above, except that the second ohmic electrode 238 and the third ohmic electrode 248 are omitted. Thus, detailed description of items identical or similar to those of the light emitting device 200 will be omitted to avoid redundancy.

[0373] The second LED stack 233 includes a first conductive semiconductor layer 233a, an active layer, and a second conductive semiconductor layer 233b. The second conductive semiconductor layer 233b may cover substantially the entire lower surface of the first conductive semiconductor layer 233a, and thus, the lower surface of the first conductive semiconductor layer 233a may not be exposed. The third LED stack 243 includes a first conductive semiconductor layer 243a, an active layer, and a second conductive semiconductor layer 243b. The second conductive semiconductor layer 243b may cover substantially the entire lower surface of the first conductive semiconductor layer 243a, and thus, the lower surface of the first conductive semiconductor layer 243a may not be exposed. In this way, the second ohmic electrode 238 and the third ohmic electrode 248 of the light emitting device 200 are omitted in the light emitting device 2000.

[0374] The first color filter 237 may be patterned in advance, and then a through hole for connecting the connectors to each other may be easily formed. However, the inventive concept is not limited thereto, and the through hole may penetrate the first color filter 237 .

[0375] The connector 2168b may penetrate the first and second conductive semiconductor layers 233a and 233b of the second LED stack 233 and the second transparent electrode 235 to be connected to the connection pad 228b. The connector 2168b may be connected to the upper surface of the first conductive semiconductor layer 233a.

[0376] Connector 2168c is substantially similar to Fig. 15BThe first color filter 237 may be patterned in advance and thus not exposed to the inner wall of the hole in which the connector 2168c is formed. However, the inventive concept is not limited thereto, and the connector 2168c may be exposed to the inner wall of the hole.

[0377] The connector 2168d is connected to the second current spreading layer 236 and to the first reflective electrode 226. The connector 2168d may be spaced apart from the second transparent electrode 235 and may be electrically connected to the second transparent electrode 235 through the second current spreading layer 236. The connector 2168d may include a pad region on the second LED stack 233. The pad region may be provided in a hole penetrating the second LED stack 233.

[0378] The insulating layer 2161 insulates the connector 2168b from the second conductive semiconductor layer 233b of the second LED stack 233 and the second transparent electrode 235. The insulating layer 2161 electrically insulates the connector 2168c from the first LED stack 223 and the second LED stack 233, and also insulates the connector 2168d from the first conductive semiconductor layer 223a of the first LED stack 223.

[0379] The first bonding layer 2139 may bond the first LED stack 223 and the first color filter 237 to each other, and may also contact a portion of the second transparent electrode 235. In addition, the second bonding layer 2169 may contact the second color filter 247 and the third transparent electrode 245.

[0380] The connector 2178c is connected to the first conductive semiconductor layer 243a of the third LED stack 243 and is also connected to the connector 2168c. The connector 2178c may be connected to the upper surface of the first conductive semiconductor layer 243a. The connector 2178c is insulated from the second conductive semiconductor layer 243b and the third transparent electrode 245 by the insulating layer 2171.

[0381] The connection member 2178d connects the third current spreading layer 246 and the connection member 168 to each other. The upper surface of the connection member 2178d may be positioned on the third LED stack 243. However, the position of the upper surface of the connection member 2178d is not necessarily limited thereto, and the upper surface of the connection member 2178d may be positioned in a hole formed in the third LED stack 243.

[0382] The insulating layer 2171 may cover the sidewalls of the hole formed in the third LED stack 243 and insulate the connector 2178c from the second conductive type semiconductor layer 243b and the third transparent electrode 245. In addition, the insulating layer 2171 may insulate the connector 2178d from the first conductive type semiconductor layer 243a.

[0383] Fig.28A , Fig.28B , Fig.29A , Fig.29B , Fig. 30A , Fig. 30B , Fig.31A , Fig.31B , Fig.32A , Fig.32B , Fig.33A , Fig.33B , Fig.34A and Fig.34B are a plan view and a cross-sectional view illustrating a method of manufacturing the light emitting device 2000 according to an exemplary embodiment.

[0384] Reference Fig.28A and Fig.28B , a second LED stack 233 is grown on the second substrate 231, and a second transparent electrode 235 is formed on the second LED stack 233. According to the exemplary embodiment shown, reference is omitted. Fig.17A and Fig. 17B A process of partially removing the second transparent electrode 235 and the second conductive type semiconductor layer 233 b is described.

[0385] The first color filter 237 is formed on the second transparent electrode 235. Since the material forming the first color filter 237 is the same as the reference Fig.15A and Fig. 15B The materials described are substantially the same, so in order to avoid redundancy, a detailed description thereof will be omitted. Then, the first color filter 237 is patterned to expose the second transparent electrode 235. The region exposing the second transparent electrode 235 may include a region to which the extension 236b is to be connected, and may also include a region in which a through hole is to be formed.

[0386] Then, a second current diffusion layer 236 is formed on the first color filter 237. Fig.17A and Fig. 17B The described second current spreading layer 236 is substantially the same, so a detailed description thereof will be omitted.

[0387] Reference Fig.29A and Fig.29B , a third LED stack 243 is grown on the third substrate 241, and a third transparent electrode 245 is formed on the third LED stack 243. According to the exemplary embodiment shown, reference is omitted. Fig.18A and Fig.18B A process of partially removing the third transparent electrode 245 and the second conductive type semiconductor layer 243b is described.

[0388] The second color filter 247 is formed on the third transparent electrode 245. Since the material forming the second color filter 247 is the same as the reference Fig.15A and Fig. 15B The described materials are substantially the same, so a detailed description thereof will be omitted to avoid redundancy.

[0389] The second color filter 247 is patterned to expose the third transparent electrode 245. The region where the third transparent electrode 245 is exposed may include a region to which the extension 246b is to be connected, and may also include a region in which a through hole is to be formed.

[0390] Then, a third current diffusion layer 246 is formed on the second color filter 247. Fig.18A and Fig.18B The third current spreading layer 246 described is substantially the same, so a detailed description thereof will be omitted.

[0391] Reference Fig. 30A and Fig. 30B , bump pads 251a, 251b, 251c, and 251d are formed on the first LED stack 223, and the substrate 221 is removed to expose the upper surface of the first LED stack 223. A surface roughened by surface texturing may be formed on the exposed upper surface of the first LED stack 223.

[0392] Then, the first bonding layer 2139 is used to Fig.28A and Fig.28B The second LED stack 233 is bonded to the first LED stack 223 , and the substrate 231 is removed.

[0393] Reference Fig.31A and Fig.31B , forming holes h1, h2, and h3 penetrating the second LED stack 233 and the first LED stack 223. The holes h1, h2, and h3 also penetrate the first bonding layer 2139.

[0394] The hole h1 exposes the second current spreading layer 236, and also exposes the first reflective layer 226. The first LED stack 233, the second transparent electrode 235, the first color filter 237, the first LED stack 223, the insulating layer 225, etc. may be exposed on the sidewall of the hole h1.

[0395] The hole h2 exposes the connection pad 228c. In addition, the second LED stack 233, the second transparent electrode 235, the first LED stack 223 and the insulating layer 225 may be exposed on the sidewall of the hole h2. The first color filter 237 may be spaced apart from the hole h2, but the inventive concept is not limited thereto, and the first color filter 237 may be exposed on the sidewall of the hole h2.

[0396] The hole h3 exposes the connection pad 228b. In addition, the second LED stack 233, the second transparent electrode 235, the first LED stack 223 and the insulating layer 225 may be exposed on the sidewall of the hole. The first color filter 237 may be spaced apart from the hole h3, but the inventive concept is not limited thereto, and the first color filter 237 may be exposed on the sidewall of the hole h3.

[0397] Reference Fig.32A and Fig.32B Then, an insulating layer 2161 is formed to cover the sidewalls of the holes h1 , h2 , and h3 . The insulating layer 2161 may also cover the upper surface of the second LED stack 233 .

[0398] The insulating layer 2161 exposes the first reflective electrode 226 and the connection pads 228 b and 228 c , and also exposes the second current spreading layer 236 .

[0399] Connectors 2168d, 2168c, and 2168b are formed in the holes h1, h2, and h3. Connector 2168b is connected to the first conductive semiconductor layer 233a and to the connection pad 228b. Connector 2168c is insulated from the second LED stack 233 and connected to the connection pad 228c. Connector 2168d is connected to the second current spreading layer 236 and to the first reflective electrode 226.

[0400] Then, refer to Fig.33A and Fig.33B ,Will Fig.29A and Fig.29B The third LED stack 243 is bonded to the second LED stack 233 and the substrate 241 is removed. The third LED stack 243 may be bonded to the second LED stack 233 via the second bonding layer 2169 .

[0401] Reference Fig.34A and Fig.34B , a hole is formed through the third LED stack 243 to expose the connectors 2168c and 2168d, an insulating layer 2171 is formed to cover the sidewalls of the hole, and then connectors 2178c and 2178d are formed.

[0402] The connector 2178c may be connected to the upper surface of the second conductive semiconductor layer 243a and may also be connected to the pad region of the connector 2168c. The pad region of the connector 2168c may be wider than the width of the hole penetrating the third LED stack 243. Meanwhile, the connector 2178d is connected to the upper surface of the third current spreading layer 246 and is also connected to the connector 2168d.

[0403] Then, the light emitting device 2000 is completed by dividing the substrate into light emitting device regions. Fig.34AAs shown, bump pads 251a, 251b, 251c and 251d may be disposed at four corners of each light emitting device 2000. In addition, bump pads 251a, 251b, 251c and 251d may have a substantially rectangular shape, but are not necessarily limited thereto. In some exemplary embodiments, an insulating layer covering the side surface of each light emitting device may be additionally formed, and the insulating layer may include a reflective layer that reflects light or an absorbing layer that absorbs light as described above. Therefore, light directed to the side surface from the first LED stack 223, the second LED stack 233, and the third LED stack 243 may be reflected or absorbed to prevent light interference between pixels, and the light efficiency of the light emitting device may be improved, or the contrast of the display device may be improved.

[0404] Meanwhile, the process of forming the through hole and the process of forming the connector are described as being performed whenever the second LED stack 233 and the third LED stack 243 are joined to each other. However, the process for connecting the connector may be performed after both the second LED stack 233 and the third LED stack 243 are joined. In addition, the connector is described as being formed using the through hole, but the inventive concept is not limited thereto. For example, the side surface of the light emitting device may be etched, and the connector may be formed along the side surface of the light emitting device.

[0405] Fig.35A and Fig.35B 1 is a plan view and a cross-sectional view showing a light emitting diode stack structure according to another exemplary embodiment. The light emitting diode stack structure according to the exemplary embodiment includes Fig.36A and Fig.36B 2001 is shown in FIG. 2001 , in which a second LED stack 233 and a third LED stack 243 are joined together.

[0406] Reference Fig.35A and Fig.35B , the light emitting diode stack structure may include bump pads 251a, 251b, 251c and 251d, filler 253, a first LED stack 223, a second LED stack 233, a third LED stack 243, insulating layers 225 and 229, a first reflective electrode 226, a second transparent electrode 235, a third transparent electrode 245, a first ohmic electrode 228a, a second ohmic electrode 238, connecting pads 228b and 228c, a second current spreading layer 2136, a third current spreading layer 2146, a first color filter 237, a second color filter 247, a first bonding layer 239, and a second bonding layer 269. Although Fig.35A Only one light emitting device region is shown, but a plurality of light emitting device regions may be continuously connected to each other.

[0407] The structure from the bump pads 251a, 251b, 251c and 251d and the filler 253 to the second LED stack 233 is Fig.21A and Fig. 21B The structures are substantially the same, and therefore, a detailed description thereof will be omitted.

[0408] However, despite Fig.21A and Fig. 21B The second current spreading layer 236 of FIG. 1 has a hollow portion in the pad region 236 a , but the second current spreading layer 2136 according to the illustrated exemplary embodiment may eliminate the need for the hollow portion.

[0409] In addition, the second ohmic electrode 238 is shown to be formed on some regions of the first conductive type semiconductor layer 233a, but in some exemplary embodiments, as shown in FIG. Fig. 30A and Fig. 30B As described, bonding can also be performed when the second ohmic electrode 238 is omitted.

[0410] At the same time, return to the reference FIG. 21A to FIG. 22B , the second LED stack 233 is bonded to the first LED stack 223, and then through holes h1, h2, and h3 are formed. However, in the illustrated exemplary embodiment, the process of forming the through holes is omitted, and the third LED stack 243 is bonded to the second LED stack 233 using the second bonding layer 269.

[0411] The third LED stack 243, the second color filter, and the third current spreading layer 2146 according to the illustrated exemplary embodiment can be referred to as Fig.29A and Fig.29B The method described above is used to manufacture the substrate 241 after bonding the third LED stack 243. However, unlike Fig.24A Unlike the third current spreading layer 246 shown in FIG. 2 , the third current spreading layer 2146 may not require a hollow portion.

[0412] In addition, the third LED stack 243 is shown to be bonded to the second LED stack 233 when the third ohmic electrode 248 is omitted on the first conductive semiconductor layer 243a, but the present inventive concept is not limited thereto. Fig.18A and Fig.18B As described, when forming the third ohmic electrode 248 , a portion of the first conductive semiconductor layer 243 a may be exposed, the third ohmic electrode 248 may be formed on the exposed first conductive semiconductor layer 243 a , and the third LED stack 243 may be bonded to the second LED stack 233 .

[0413] Therefore, it is possible to provide Fig.35B The light emitting diode stacking structure shown in FIG. 2 is used to form a light emitting device 2001 .

[0414] Fig.36A is a plan view of the light emitting device 2001, Fig.36B and Fig.36C Along the Fig.36A Schematic cross-sectional view taken along line GH and line IJ.

[0415] Reference Fig.36A , Fig.36B and Fig.36C , because the stacking structure of the light emitting device 2001 is similar to that of the reference Fig.35A and Fig.35B The described stacked structures are substantially the same, so a detailed description thereof is omitted, and hereinafter, the insulating layer 2261 having a changed shape by patterning and the connectors 2278 b , 2278 c , and 2278 d will be described.

[0416] The third LED stack 243 , the third transparent electrode 245 , and the second color filter 247 are partially removed to expose the third current spreading layer 2146 , and the second LED stack 233 , the second transparent electrode 245 , and the first color filter 237 are removed to expose the second ohmic electrode 238 and the second current spreading layer 2136 .

[0417] Furthermore, the first bonding layer 239 , the first LED stack 223 , and the insulating layer 225 are partially removed to expose the connection pads 228 b and 228 c and the first reflective electrode 226 .

[0418] In addition, by exposing the upper surface of the insulating layer 229 or the filler 253 , patterning may also be performed on a cutting region for separating the light emitting devices.

[0419] The insulating layer 2261 covers the side surfaces of the first LED stack 223, the second LED stack 233, the third LED stack 243 and other layers. The insulating layer 2261 has an opening exposing the third current spreading layer 2146, the second ohmic electrode 238, the second current spreading layer 2136, the first reflective electrode 226, and the connecting pads 228b and 228c. The insulating layer 2261 can be formed of a single layer or multiple layers of a light-transmitting material such as SiO2, Si3N4, etc. The insulating layer 2261 can also cover substantially the entire upper surface of the third LED stack 243. In addition, the insulating layer 2261 may include a distributed Bragg reflector that reflects light emitted from the first LED stack 223, the second LED stack 233, and the third LED stack 243, thereby preventing light from being emitted to the side surface of the light-emitting device 2001. Optionally, the insulating layer 2261 may include a transparent insulating film and a reflective metal layer or an organic reflective layer of a multilayer structure formed thereon, thereby reflecting light, or may include a light absorbing layer such as a black epoxy resin to block light. The insulating layer 2261 may include a reflective layer or an absorption layer, thereby preventing light interference between pixels and improving the contrast of the display device. When the insulating layer 2261 includes a reflective layer or an absorption layer, the insulating layer 2261 has an opening exposing the upper surface of the third LED stack 243.

[0420] The connectors 2278b, 2278c and 2278d are disposed on the insulating layer 2261 along the side surface of the light emitting device 2001. Fig.36B As shown, the connector 2278c connects the first conductive semiconductor layer 243a of the third LED stack 243 to the connecting pad 228c. Therefore, the first conductive semiconductor layer 243a of the third LED stack 243 is electrically connected to the third bump pad 251c. The connector 2278c can directly connect the third LED stack 243a to the connecting pad 228c. In this case, the connector 2278c may include an extension portion for current distribution located on the second LED stack 233. In some exemplary embodiments, when the third ohmic electrode 248 is formed, the connector 2278c may be connected to the third ohmic electrode 248. In this case, the third ohmic electrode 248 may include an extension portion and a pad area.

[0421] Reference Fig.36C, the connector 2278b connects the second ohmic electrode 238 to the connecting pad 228b. Therefore, the first conductive semiconductor layer 233a of the second LED stack 233 is electrically connected to the second bump pad 251b. When the second ohmic electrode 238 is omitted in some exemplary embodiments, the connector 2278b may be connected to the first conductive semiconductor layer 233a. The connector 2278c is connected to the third current diffusion layer 2146, the second current diffusion layer 2136, and the first reflective electrode 226. Therefore, the second conductive semiconductor layer 243b of the third LED stack 243, the second conductive semiconductor layer 233b of the second LED stack 233, and the second conductive semiconductor layer 223b of the first LED stack 223 are electrically connected to the common bump pad 251d.

[0422] In the illustrated exemplary embodiment, one connector 278d is described as connecting the third current diffusion layer 2146, the second current diffusion layer 2136, and the first reflective electrode 226 to each other, however, the inventive concept is not limited thereto, and a plurality of connectors may be used. For example, the third current diffusion layer 2146 and the second current diffusion layer 2136 may be connected to each other through one connector, and the second current diffusion layer 2136 and the first reflective electrode 226 may also be connected to each other through another connector.

[0423] By referring to Fig.35A and Fig.35B The described light emitting diode stack structure is patterned and divided into individual units to manufacture the light emitting device 2001 .

[0424] More specifically, the third LED stack 243, the third transparent electrode 245, and the second color filter 247 are patterned and partially removed. Fig.36C As shown, the third LED stack 243, the third transparent electrode 245, and the second color filter 247 are removed to expose the third current spreading layer 2146. The third LED stack 243, the third transparent electrode 245, and the second color filter 247 are removed from the cutting area for individually dividing the light emitting devices, and the periphery of the upper area of ​​the connection pads 228b and 228c and a portion of the upper area of ​​the first reflective electrode 226 are also removed. At the same time, when the third ohmic electrode 248 is formed on the third LED stack 243, the third ohmic electrode 248 is also exposed.

[0425] Then, the second bonding layer 269 and the second LED stack 233 are patterned to expose the second ohmic electrode 238. In addition, the second transparent electrode 235 and the first color filter 237 are removed to expose the second current spreading layer 2136. The second bonding layer 269, the second LED stack 233, the second transparent electrode 235, and the first color filter 237 are removed from the cutting area for individually dividing the light emitting devices.

[0426] Then, the first bonding layer 239, the first LED stack 223 and the insulating layer 225 are patterned to expose the connection pads 228b and 228c and the first reflective electrode 226. The first bonding layer 239, the first LED stack 223 and the insulating layer 225 are removed from a cutting region for individually dividing the light emitting devices.

[0427] Then, an insulating layer 2261 is formed to cover the exposed side surface of the light emitting device. The insulating layer 2261 is patterned using a photolithography and etching process, etc., and thus, an opening exposing the second current diffusion layer 236, the third current diffusion layer 246, the second ohmic electrode 238, the connection pads 228b and 228c, and the first reflective electrode 226 is formed.

[0428] Then, connectors 2278 b , 2278 c , and 2278 d are formed to electrically connect the exposed second current spreading layer 236 , the third current spreading layer 246 , the second ohmic electrode 238 , the connection pads 228 b and 228 c , and the first reflective electrode 226 .

[0429] Fig.37 is a schematic plan view of a display device according to an exemplary embodiment.

[0430] Reference Fig.37 , a display apparatus according to an exemplary embodiment includes a circuit board 301 and a plurality of light emitting devices 300 .

[0431] Circuit board 301 may include circuits for passive matrix driving or active matrix driving. In one exemplary embodiment, circuit board 301 may include interconnects and resistors. In another exemplary embodiment, circuit board 301 may include interconnects, transistors, and capacitors. Circuit board 301 may also have electrode pads disposed on its upper surface to allow electrical connection to the circuits therein.

[0432] The light emitting device 300 is arranged on the circuit board 301. Each light emitting device 300 may constitute a pixel. The light emitting device 300 includes electrode pads 373a, 373b, 373c, 373d electrically connected to the circuit board 301. In addition, the light emitting device 300 may include a substrate 341 located at the upper surface thereof. Because the light emitting devices 300 are isolated from each other, the substrate 341 disposed at the upper surface of the light emitting device 300 is also isolated from each other.

[0433] Will refer to Fig.38A and Fig.38B The details of the light emitting device 300 are described. Fig.38A is a schematic plan view of a light emitting device 300 for a display according to an exemplary embodiment, Fig.38B It is along Fig.38AAlthough the electrode pads 373a, 373b, 373c, 373d are shown and described as being disposed on the upper side of the light emitting device 300, the light emitting device 300 may be flipped and bonded on the upper side. Fig.37 on the circuit board 301, and the electrode pads 373a, 373b, 373c, 373d can be set on the lower side.

[0434] Reference Fig.38A and Fig.38B The light emitting device 300 may include a first substrate 321, a second substrate 341, a distributed Bragg reflector 322, a first LED stack 323, a second LED stack 333, a third LED stack 343, a first transparent electrode 325, a second transparent electrode 335, a third transparent electrode 345, an ohmic electrode 346, a first current diffuser 328, a second current diffuser 338, a third current diffuser 348, a first color filter 347, a second color filter 357, a first bonding layer 349, a second bonding layer 359, a lower insulating layer 361, an upper insulating layer 371, an ohmic electrode 363a, through-hole vias 363b, 365a, 365b, 367a, 367b, and electrode pads 373a, 373b, 373c, 373d.

[0435] The first substrate 321 may support the LED stacks 323, 333, 343. The first substrate 321 may be a growth substrate for the first LED stack 323, for example, a GaAs substrate. Specifically, the first substrate 321 may have conductivity.

[0436] The second substrate 341 may support LED stacks 323, 333, 343. The LED stacks 323, 333, 343 are disposed between the first substrate 321 and the second substrate 341. The second substrate 341 may be a growth substrate for the third LED stack 343. For example, the second substrate 341 may be a sapphire substrate or a GaN substrate, more specifically, a patterned sapphire substrate. The first LED stack to the third LED stack are disposed on the second substrate 341 in the order of the third LED stack 343, the second LED stack 333, and the first LED stack 323 from the second substrate 341. In an exemplary embodiment, a single third LED stack 343 may be disposed on a single second substrate 341. The second LED stack 333, the first LED stack 323, and the first substrate 321 are disposed on the third LED stack 343. Therefore, the light emitting device 300 may have a single chip structure of a single pixel.

[0437] In another exemplary embodiment, a plurality of third LED stacks 343 may be disposed on a single second substrate 341. The second LED stack 333, the first LED stack 323, and the first substrate 321 are disposed on each third LED stack 343, whereby the light emitting device 300 has a single chip structure of a plurality of pixels.

[0438] In some exemplary embodiments, the second substrate 341 may be omitted, and the lower surface of the third LED stack 343 may be exposed. In this case, a roughened surface may be formed on the lower surface of the third LED stack 343 by surface texturing.

[0439] Each of the first LED stack 323, the second LED stack 333, and the third LED stack 343 includes a first conductive semiconductor layer 323a, 333a, and 343a, a second conductive semiconductor layer 323b, 333b, and 343b, and an active layer interposed between the first conductive semiconductor layer 323a, 333a, and 343a and the second conductive semiconductor layer 323b, 333b, and 343b, respectively. The active layer may have a multi-quantum well structure.

[0440] The LED stack emitting light with a shorter wavelength may be disposed closer to the second substrate 341. For example, the first LED stack 323 may be an inorganic light emitting diode suitable for emitting red light, the second LED stack 333 may be an inorganic light emitting diode suitable for emitting green light, and the third LED stack 343 may be an inorganic light emitting diode suitable for emitting blue light. The first LED stack 323 may include a well layer based on AlGaInP, the second LED stack 333 may include a well layer based on AlGaInP or AlGaInN, and the third LED stack 343 may include a well layer based on AlGaInN. However, the inventive concept is not limited thereto. When the light emitting device 300 includes a micro-LED having a surface area of ​​less than about 10,000 square microns or less than about 4,000 square microns or 2,500 square microns as known in the art, the first LED stack 323 may emit any one of red light, green light, and blue light, and the second LED stack 333 and the third LED stack 343 may emit different ones of red light, green light, and blue light without negatively affecting the operation due to the small form factor of the micro-LED.

[0441] In addition, the first conductive semiconductor layer 323a, 333a and 343a of each LED stack in the LED stacks 323, 333, 343 may be an n-type semiconductor layer, and the second conductive semiconductor layer 323b, 333b and 343b of each LED stack in the LED stacks 323, 333, 343 may be a p-type semiconductor layer. According to the exemplary embodiment shown, the upper surface of the first LED stack 323 is an n-type semiconductor layer 323a, the upper surface of the second LED stack 333 is an n-type semiconductor layer 333a, and the upper surface of the third LED stack 343 is a p-type semiconductor layer 343b. Specifically, only the semiconductor layers of the third LED stack 343 are stacked in an order different from that of the first LED stack 323 and the second LED stack 333. The first conductive semiconductor layer 343a of the third LED stack 343 may be subjected to surface texturing to improve light extraction efficiency. In some exemplary embodiments, the first conductive semiconductor layer 333a of the second LED stack 333 may also be subjected to surface texturing.

[0442] The first LED stack 323, the second LED stack 333, and the third LED stack 343 may be stacked to overlap each other and may have substantially the same light emitting area. In addition, in each of the LED stacks 323, 333, 343, the first conductive semiconductor layers 323a, 333a, and 343a may have substantially the same area as the second conductive semiconductor layers 323b, 333b, and 343b. Specifically, in each of the first LED stack 323 and the second LED stack 333, the first conductive semiconductor layers 323a and 333a may completely overlap with the second conductive semiconductor layers 323b and 333b, respectively. In the third LED stack 343, the hole h5 (see Fig.45A ) is formed on the second conductive type semiconductor layer 343b to expose the first conductive type semiconductor layer 343a, and thus the first conductive type semiconductor layer 343a has a slightly larger area than the second conductive type semiconductor layer 343b.

[0443] The first LED stack 323 is disposed away from the second substrate 341, the second LED stack 333 is disposed below the first LED stack 323, and the third LED stack 343 is disposed below the second LED stack 333. Since the wavelength of light emitted by the first LED stack 323 is longer than the wavelengths of light emitted by the second LED stack 333 and the third LED stack 343, light generated from the first LED stack 323 may be emitted to the outside after passing through the second LED stack 333, the third LED stack 343, and the second substrate 341. In addition, since the wavelength of light emitted by the second LED stack 333 is longer than the wavelength of light emitted by the third LED stack 343, light generated from the second LED stack 333 may be emitted to the outside after passing through the third LED stack 343 and the second substrate 341.

[0444] The distributed Bragg reflector 322 may be disposed between the first substrate 321 and the first LED stack 323. The distributed Bragg reflector 322 reflects light generated from the first LED stack 323 to prevent the light from being lost by absorption by the substrate 321. For example, the distributed Bragg reflector 322 may be formed by alternately stacking AlAs-based semiconductor layers and AlGaAs-based semiconductor layers on each other.

[0445] The first transparent electrode 325 may be disposed between the first LED stack 323 and the second LED stack 333. The first transparent electrode 325 makes ohmic contact with the second conductive semiconductor layer 323b of the first LED stack 323 and transmits light generated from the first LED stack 323. The first transparent electrode 325 may include a metal layer or a transparent oxide layer, for example, an indium tin oxide (ITO) layer, etc.

[0446] The second transparent electrode 335 makes ohmic contact with the second conductive semiconductor layer 333b of the second LED stack 333. As shown in the figure, the second transparent electrode 335 contacts the lower surface of the second LED stack 333 between the second LED stack 333 and the third LED stack 343. The second transparent electrode 335 may include a metal layer or a conductive oxide layer transparent to red and green light.

[0447] The third transparent electrode 345 is in ohmic contact with the second conductive semiconductor layer 343b of the third LED stack 343. The third transparent electrode 345 may be disposed between the second LED stack 333 and the third LED stack 343 and contact the upper surface of the third LED stack 343. The third transparent electrode 345 may include a metal layer or a conductive oxide layer transparent to red and green light. The third transparent electrode 345 may also be transparent to blue light. Each of the second transparent electrode 335 and the third transparent electrode 345 is in ohmic contact with the p-type semiconductor layer of each LED stack to facilitate current diffusion. Examples of the conductive oxide layer for the second transparent electrode 335 and the third transparent electrode 345 may include SnO2, InO2, ITO, ZnO, IZO, etc.

[0448] The first current spreader 328, the second current spreader 338, and the third current spreader 348 may be provided to spread the current in the second conductive semiconductor layer 323b of the first LED stack 323, the second conductive semiconductor layer 333b of the second LED stack 333, and the second conductive semiconductor layer 343b of the third LED stack 343. As shown in the figure, the first current spreader 328 may be provided on the second conductive semiconductor layer 323b exposed by the first transparent electrode 325, the second current spreader 338 may be provided on the second conductive semiconductor layer 333b exposed by the second transparent electrode 335, and the third current spreader 348 may be provided on the second conductive semiconductor layer 343b exposed by the third transparent electrode 345. Fig.38A As shown, each of the first current spreader 328, the second current spreader 338, and the third current spreader 348 may be disposed along an edge of each of the first LED stack 323, the second LED stack 333, and the third LED stack 343. In addition, each of the first current spreader 328, the second current spreader 338, and the third current spreader 348 may have a substantially annular shape to surround the center of each LED stack, but the inventive concept is not limited thereto, and may have a substantially straight shape or a curved shape. In addition, the first current spreader 328, the second current spreader 338, and the third current spreader 348 may be disposed to overlap each other, but are not limited thereto.

[0449] The first current spreader 328, the second current spreader 338, and the third current spreader 348 may be isolated from the first transparent electrode 325, the second transparent electrode 335, and the third transparent electrode 345. Therefore, gaps may be formed between the side surface of the first current spreader 328 and the side surface of the first transparent electrode 325, between the side surface of the second current spreader 338 and the side surface of the second transparent electrode 335, and between the side surface of the third current spreader 348 and the side surface of the third transparent electrode 345. However, the inventive concept is not limited thereto, and at least one of the first current spreader 328, the second current spreader 338, and the third current spreader 348 may contact the first transparent electrode 325, the second transparent electrode 335, and the third transparent electrode 345.

[0450] The first, second, and third current spreaders 328, 338, and 348 may include a material having higher conductivity than the first, second, and third transparent electrodes 325, 335, and 345. In this manner, current may be uniformly spread over a wide area of ​​the second conductive type semiconductor layers 323b, 333b, and 343b.

[0451] The ohmic electrode 346 is in ohmic contact with the first conductive semiconductor layer 343a of the first LED stack layer 343. The ohmic electrode 346 may be disposed on the first conductive semiconductor layer 343a exposed by the third transparent electrode 345 and the second conductive semiconductor layer 343b. For example, the ohmic electrode 346 may be formed of Ni / Au / Ti or Ni / Au / Ti / Ni. When the surface of the ohmic electrode 346 is exposed during the etching process, a Ni layer may be formed on the surface of the ohmic electrode 346 and used as an etching stop layer. The ohmic electrode 346 may be formed to have various shapes. In an exemplary embodiment, the ohmic electrode 346 may have a substantially elongated shape to serve as a current diffuser. In some exemplary embodiments, the ohmic electrode 346 may be omitted.

[0452] The first color filter 347 may be disposed between the third transparent electrode 345 and the second LED stack 333, and the second color filter 357 may be disposed between the second LED stack 333 and the first LED stack 323. The first color filter 347 transmits light generated from the first LED stack 323 and the second LED stack 333, while reflecting light generated from the third LED stack 343. The second color filter 357 transmits light generated from the first LED stack 323, while reflecting light generated from the second LED stack 333. Therefore, light generated from the first LED stack 323 may be emitted to the outside through the second LED stack 333 and the third LED stack 343, and light generated from the second LED stack 333 may be emitted to the outside through the third LED stack 343. In addition, light loss may be prevented by preventing light generated from the second LED stack 333 from entering the first LED stack 323 or preventing light generated from the third LED stack 343 from entering the second LED stack 333.

[0453] In some exemplary embodiments, the second color filter 357 may reflect light generated from the third LED stack 343 .

[0454] For example, the first color filter 347 and the second color filter 357 can be a low-pass filter that allows light in a low frequency band (e.g., a long wave band) to pass through it, a band-pass filter that allows light in a predetermined wave band to pass through it, or a band-stop filter that prevents light in a predetermined wave band from passing through it. Specifically, each of the first color filter 347 and the second color filter 357 can be formed by alternately stacking insulating layers with different refractive indices (such as TiO2 and SiO2 as examples) on top of each other. Specifically, each of the first color filter 347 and the second color filter 357 can include a distributed Bragg reflector (DBR). In addition, the stop band of the distributed Bragg reflector can be controlled by adjusting the thickness of the TiO2 layer and the thickness of the SiO2 layer. Low-pass filters and band-pass filters can also be formed by alternately stacking insulating layers with different refractive indices on top of each other.

[0455] The first bonding layer 349 bonds the second LED stack 333 to the third LED stack 343. The first bonding layer 349 may bond the first color filter 347 to the second transparent electrode 335 between the first color filter 347 and the second transparent electrode 335. For example, the first bonding layer 349 may be formed of a transparent organic material or a transparent inorganic material. Examples of organic materials may include SU8, poly(methyl methacrylate) (PMMA), polyimide, polyparaxylene, benzocyclobutene (BCB), etc., and examples of inorganic materials may include Al2O3, SiO2, SiN x Etc. More specifically, the first bonding layer 349 may be formed of spin-on glass (SOG).

[0456] The second bonding layer 359 bonds the second LED stack 333 to the first LED stack 323. As shown, the second bonding layer 359 may be disposed between the second color filter 357 and the first transparent electrode 325. The second bonding layer 359 may be formed of substantially the same material as the first bonding layer 349.

[0457] Holes h1, h2, h3, h4, and h5 are formed through the first substrate 321. The hole h1 may be formed through the first substrate 321, the distributed Bragg reflector 322, and the first LED stack 323 to expose the first transparent electrode 325. The hole h2 may be formed through the first substrate 321, the distributed Bragg reflector 322, the first transparent electrode 325, the second bonding layer 359, and the second color filter 357 to expose the first conductive semiconductor layer 333a of the second LED stack 333.

[0458] A hole h3 may be formed through the first substrate 321, the distributed Bragg reflector 322, the first transparent electrode 325, the second bonding layer 359, the second color filter 357, and the second LED stack 333 to expose the second transparent electrode 335. A hole h4 may be formed through the first substrate 321, the distributed Bragg reflector 322, the first transparent electrode 325, the second bonding layer 359, the second color filter 357, the second LED stack 333, the second transparent electrode 335, the first bonding layer 349, and the first color filter 347 to expose the third transparent electrode 345. A hole h5 may be formed through the first substrate 321, the distributed Bragg reflector 322, the first transparent electrode 325, the second bonding layer 359, the second color filter 357, the second LED stack 333, the second transparent electrode 335, the first bonding layer 349, and the first color filter 347 to expose the ohmic electrode 346. When the ohmic electrode 346 is omitted in some exemplary embodiments, the first conductive type semiconductor layer 343 a may be exposed through the hole h5 .

[0459] Although the holes h1, h3, and h4 are shown to be isolated from each other to expose the first, second, and third transparent electrodes 325, 335, and 345, respectively, the inventive concept is not limited thereto, and the first, second, and third transparent electrodes 325, 335, and 345 may be exposed through a single hole.

[0460] In addition, although the first to third transparent electrodes 325 , 335 , and 345 are illustrated as being exposed through the holes h1 , h3 , and h4 , in some exemplary embodiments, the first to third current spreaders 328 , 338 , and 348 may be exposed.

[0461] The lower insulating layer 361 covers the side surfaces of the first substrate 321 and the side surfaces of the first LED stack 323, the second LED stack 333, and the third LED stack 343, while covering the upper surface of the first substrate 321. The lower insulating layer 361 also covers the side surfaces of the holes h1, h2, h3, h4, and h5. However, the lower insulating layer 361 may be patterned to expose the bottom of each of the holes h1, h2, h3, h4, and h5. In addition, the lower insulating layer 361 may also be patterned to expose the upper surface of the first substrate 321.

[0462] The ohmic electrode 363a is in ohmic contact with the upper surface of the first substrate 321. The ohmic electrode 363a may be formed in an exposed region of the first substrate 321 exposed by patterning the lower insulating layer 361. For example, the ohmic electrode 363a may be formed of an Au-Te alloy or an Au-Ge alloy. Each of the through-hole paths 363b, 365b, and 367b may be connected to the first transparent electrode 325, the second transparent electrode 335, and the third transparent electrode 345, and may be connected to the first current spreader 328, the second current spreader 338, and the third current spreader 348, respectively.

[0463] The through-hole vias 363b, 365a, 365b, 367a, 367b are disposed in the holes h1, h2, h3, h4, and h5. The through-hole via 363b may be disposed in the hole h1 and may be connected to the first transparent electrode 325. The through-hole via 365a may be disposed in the hole h2 and may be in ohmic contact with the first conductive semiconductor layer 333a. The through-hole via 365b may be disposed in the hole h3 and may be electrically connected to the second transparent electrode 335. The through-hole via 367a may be disposed in the hole h5 and may be electrically connected to the first conductive semiconductor layer 343a. For example, the through-hole via 367a may be electrically connected to the ohmic electrode 345 through the hole h5. The through-hole via 367b may be disposed in the hole h4 and may be connected to the third transparent electrode 345. The through-hole vias 363 b , 365 b , and 367 b may be connected to the first, second, and third transparent electrodes 325 , 335 , and 345 , respectively, or may be connected to the first, second, and third current spreaders 328 , 338 , and 348 , respectively.

[0464] The upper insulating layer 371 covers the lower insulating layer 361 and the ohmic electrode 363a. The upper insulating layer 371 may cover the lower insulating layer 361 located at the side of the first substrate 321 and the first LED stack 323, the second LED stack 333, and the third LED stack 343. The top surface of the lower insulating layer 361 may be covered by the upper insulating layer 371. The upper insulating layer 371 may have an opening 371a for exposing the ohmic electrode 363a, and may have an opening for exposing the through-hole vias 363b, 365a, 365b, 367a, and 367b.

[0465] The lower insulating layer 361 or the upper insulating layer 371 may be formed of silicon oxide or silicon nitride, but is not limited thereto. For example, the lower insulating layer 361 or the upper insulating layer 371 may be a distributed Bragg reflector formed by stacking insulating layers having different refractive indices. Specifically, the upper insulating layer 371 may be a light reflecting layer or a light blocking layer.

[0466] The electrode pads 373a, 373b, 373c, 373d are disposed on the upper insulating layer 371 and are electrically connected to the first LED stack 323, the second LED stack 333, and the third LED stack 343. For example, the first electrode pad 373a is electrically connected to the ohmic electrode 363a exposed through the opening 371a of the upper insulating layer 371, and the second electrode pad 373b is electrically connected to the through-hole via 365a exposed through the opening of the upper insulating layer 371. In addition, the third electrode pad 373c is electrically connected to the through-hole via 367a exposed through the opening of the upper insulating layer 371. The common electrode pad 373d is electrically connected to the through-hole vias 363b, 365b, and 367b in common.

[0467] Therefore, the common electrode pad 373d is electrically connected to the second conductive semiconductor layer 323b of the first LED stack 323, the second conductive semiconductor layer 333b of the second LED stack 333, and the second conductive semiconductor layer 343b of the third LED stack 343, and each of the electrode pads 373a, 373b, 373c is electrically connected to the first conductive semiconductor layer 323a of the first LED stack 323, the first conductive semiconductor layer 333a of the second LED stack 333, and the first conductive semiconductor layer 343a of the third LED stack 343, respectively.

[0468] According to the exemplary embodiment shown, the first LED stack 323 is electrically connected to the electrode pads 373d and 373a, the second LED stack 333 is electrically connected to the electrode pads 373d and 373b, and the third LED stack 343 is electrically connected to the electrode pads 373d and 373c. Therefore, the anode of the first LED stack 323, the anode of the second LED stack 333, and the anode of the third LED stack 343 are electrically connected to the electrode pad 373d, and the cathode of the first LED stack 323, the cathode of the second LED stack 333, and the cathode of the third LED stack 343 are electrically connected to the first electrode pad 373a, the second electrode pad 373b, and the third electrode pad 373c, respectively. Therefore, the first LED stack 323, the second LED stack 333, and the third LED stack 343 can be driven independently.

[0469] Fig.39A , Fig.39B , Fig.40A , Fig.40B , Fig.41A , Fig.41B , Fig.42 , Fig.43 , Fig.44 , Fig.45A , Fig.45B , Fig.46A , Fig.46B , Fig.47A , Fig.47B , Fig.48A , Fig.48B , Fig.49A and Fig.49B Schematic plan view and cross-sectional view showing a method of manufacturing a light emitting device for a display according to an exemplary embodiment. Fig.38A , each cross-sectional view is taken along line AA of the corresponding plan view. Fig.39B and Fig.40B Along the Fig.39A and Fig.40A A cross-sectional view taken along line BB.

[0470] Reference Fig.39A and Fig.39B , a first LED stack 323 is grown on a first substrate 321. For example, the first substrate 321 may be a GaAs substrate. The first LED stack 323 may include a semiconductor layer based on AlGaInP, and includes a first conductive type semiconductor layer 323a, an active layer, and a second conductive type semiconductor layer 323b. The first conductive type may be an n-type, and the second conductive type may be a p-type. A distributed Bragg reflector 322 may be formed before growing the first LED stack 323. For example, the distributed Bragg reflector 322 may have a stacked structure formed by repeatedly stacking AlAs / AlGaAs layers.

[0471] A first transparent electrode 325 may be formed on the second conductive type semiconductor layer 323b. The first transparent electrode 325 may be formed of a transparent oxide layer such as indium tin oxide (ITO), a transparent metal layer, or the like.

[0472] The first transparent electrode 325 may be formed to have an opening for exposing the second conductive semiconductor layer 323b, and the first current spreader 328 may be formed in the opening. The first transparent electrode 325 may be patterned by, for example, photolithography and etching techniques, which may form an opening for exposing the second conductive semiconductor layer 323b. The opening of the first transparent electrode 325 may define a region in which the first current spreader 328 may be formed.

[0473] although Fig.39A The first current spreader 328 is shown as having a substantially rectangular shape, but the inventive concept is not limited thereto. For example, the first current spreader 328 may have various shapes, such as an extended line or a curved line shape. The first current spreader 328 may be formed by a lift-off technique, etc., and its side may be isolated from the first transparent electrode 325. The first current spreader 328 may be formed to have the same or similar thickness as the first transparent electrode 325.

[0474] Reference Fig.40A and Fig.40B , a second LED stack 333 is grown on the substrate 331, and a second transparent electrode 335 is formed on the second LED stack 333. The second LED stack 333 may include a semiconductor layer based on AlGaInP or a semiconductor layer based on AlGaInN, and may include a first conductive type semiconductor layer 333a, an active layer, and a second conductive type semiconductor layer 333b. The substrate 331 may be a substrate on which a semiconductor layer based on AlGaInP can be grown, such as a GaAs substrate or a GaP substrate, or a substrate on which a semiconductor layer based on AlGaInN can be grown, such as a sapphire substrate. The first conductive type may be an n-type, and the second conductive type may be a p-type. The composition ratio of Al, Ga, and In for the second LED stack 333 may be determined so that the second LED stack 333 may emit, for example, green light. In addition, when a GaP substrate is used, a pure GaP layer or a GaP layer doped with nitrogen (N) is formed on the GaP substrate to achieve green light. The second transparent electrode 335 may be in ohmic contact with the second conductive type semiconductor layer 333b. The second transparent electrode 335 may be formed of a metal layer or a conductive oxide layer such as SnO 2 , InO 2 , ITO, ZnO, IZO, or the like.

[0475] The second transparent electrode 335 may be formed to have an opening for exposing the second conductive semiconductor layer 333b, and the second current spreader 338 may be formed in the opening. The second transparent electrode 335 may be patterned by, for example, photolithography and etching techniques, which may form an opening for exposing the second conductive semiconductor layer 333b. The opening of the second transparent electrode 335 may define a region for the second current spreader 338 to be formed.

[0476] although Fig.40A The second current spreader 338 is shown as having a substantially rectangular shape, but the inventive concept is not limited thereto. For example, the second current spreader 338 may have various shapes, such as a substantially extended line or curved line shape. The second current spreader 338 may be formed by a lift-off technique, etc., and its side may be isolated from the second transparent electrode 335. The second current spreader 338 may be formed to have the same or similar thickness as the second transparent electrode 335.

[0477] The second current spreader 338 may have the same shape and the same size as the first current spreader 328 , but is not limited thereto.

[0478] Reference Fig.41A and Fig.41B , a third LED stack 343 is grown on the second substrate 341, and a third transparent electrode 345 is formed on the third LED stack 343. The third LED stack 343 may include an AlGaInN-based semiconductor layer, and may include a first conductive type semiconductor layer 343a, an active layer, and a second conductive type semiconductor layer 343b. The first conductive type may be an n-type, and the second conductive type may be a p-type.

[0479] The second substrate 341 is a substrate on which a GaN-based semiconductor layer can be grown, and may be different from the first substrate 321. The composition ratio of AlGaInN for the third LED stack 343 is determined so that the third LED stack 343 emits, for example, blue light. The third transparent electrode 345 is in ohmic contact with the second conductive semiconductor layer 343b. The third transparent electrode 345 may be formed of a conductive oxide layer such as SnO2, InO2, ITO, ZnO, IZO, or the like.

[0480] The third transparent electrode 345 may be formed to have an opening for exposing the first conductive type semiconductor layer 343a and an opening for exposing the second conductive type semiconductor layer 343b. The opening for exposing the first conductive type semiconductor layer 343a may define a region where the ohmic electrode 346 may be formed, and the opening for exposing the second conductive type semiconductor layer 343b may define a region where the third current spreader 348 may be formed.

[0481] The third transparent electrode 345 may be patterned by, for example, photolithography and etching techniques, which may form an opening for exposing the second conductive semiconductor layer 343b. Subsequently, the first conductive semiconductor layer 343a may be exposed by partially etching the second conductive semiconductor layer 343b, and an ohmic electrode 346 may be formed in the exposed region of the first conductive semiconductor layer 343a. The ohmic electrode 346 may be formed by a metal layer and in ohmic contact with the first conductive semiconductor layer 343a. For example, the ohmic electrode 346 may be formed by a multilayer structure of Ni / Au / Ti or Ni / Au / Ti / Ni. The ohmic electrode 346 is electrically isolated from the third transparent electrode 345 and the second conductive semiconductor layer 343b.

[0482] A third current spreading member 348 is formed in the exposed region of the second conductive type semiconductor layer 343b. Fig.41A The third current spreader 348 is shown as having a substantially rectangular shape, but the inventive concept is not limited thereto. For example, the third current spreader 348 may have various shapes, such as a substantially extended line or curved line shape. The third current spreader 348 may be formed by a lift-off technique, etc., and the side of the third current spreader 348 may be isolated from the third transparent electrode 345. The third current spreader 348 may be formed to have the same or similar thickness as the third transparent electrode 345.

[0483] The third current spreader 348 may have substantially the same shape and the same size as the first current spreader 328 or the second current spreader 338 , but is not limited thereto.

[0484] Then, a first color filter 347 is formed on the second transparent electrode 345. Fig.38A and Fig.38B The described first color filter 347 is substantially the same, so a detailed description thereof will be omitted to avoid redundancy.

[0485] Reference Fig.42 ,Will Fig.40A and Fig.40B The second LED stack 333 is bonded to Fig.41A and Fig.41B The third LED stack 343 is formed on the substrate, and the second substrate 331 is removed therefrom.

[0486] The first color filter 347 is bonded to the second transparent electrode 335 to face each other. For example, a bonding material layer may be formed on the first color filter 347 and the second transparent electrode 335, and bonded to each other to form a first bonding layer 349. The bonding material layer may be a transparent organic material layer or a transparent inorganic material layer. Examples of organic materials may include SU8, poly(methyl methacrylate) (PMMA), polyimide, polyparaxylene, benzocyclobutene (BCB), etc., and examples of inorganic materials may include Al2O3, SiO2, SiN x Etc. More specifically, the first bonding layer 349 may be formed of spin-on glass (SOG).

[0487] In addition, the second current spreading member 338 may be disposed to overlap with the third current spreading member 348 , but is not limited thereto.

[0488] Thereafter, the substrate 331 may be removed from the second LED stack 333 by laser lift-off or chemical lift-off. In this way, the upper surface of the first conductive semiconductor layer 333a of the second LED stack 333 is exposed. The exposed surface of the first conductive semiconductor layer 333a may be subjected to texturing.

[0489] Reference Fig.43 , a second color filter 357 is formed on the second LED stack 333. The second color filter 357 may be formed by alternately stacking insulating layers having different refractive indices, and is aligned with the reference Fig.38A and Fig.38B The described second color filter 357 is substantially the same, and thus, a detailed description thereof will be omitted.

[0490] Then, refer to Fig.44 , the first LED stack 323 of FIG. 39 is bonded to the second LED stack 333. The second color filter 357 may be bonded to the first transparent electrode 325 to face each other. For example, a bonding material layer may be formed on the second color filter 357 and the first transparent electrode 325, and bonded to each other to form a second bonding layer 359. The bonding material layer is substantially the same as the bonding material layer described with reference to the first bonding layer 349, and therefore, a detailed description thereof will be omitted.

[0491] Meanwhile, the first diffusion member 328 may be disposed to overlap with the second current diffusion member 338 or the third current diffusion member 348 , but is not limited thereto.

[0492] Reference Fig.45A and Fig.45B , holes h1 , h2 , h3 , h4 , h5 are formed through the first substrate 321 , and isolation trenches defining a device region are also formed to expose the first substrate 341 .

[0493] The hole h1 exposes the first transparent electrode 325, the hole h2 exposes the first conductive semiconductor layer 333a, the hole h3 exposes the second transparent electrode 335, the hole h4 exposes the third transparent electrode 345, and the hole h5 exposes the ohmic electrode 346. When the hole h5 exposes the ohmic electrode 346, the upper surface of the ohmic electrode 346 may include an anti-etching layer, such as a Ni layer. In an exemplary embodiment, the holes h1, h3, and h4 may expose the first current spreader 328, the second current spreader 338, and the third current spreader 348, respectively. In addition, the hole h5 may expose the first conductive semiconductor layer 343a.

[0494] The isolation trench may expose the second substrate 341 along the periphery of each of the first LED stack 323, the second LED stack 333, and the third LED stack 343. Fig.45B It is shown that the isolation trench is formed to expose the second substrate 341, but in some exemplary embodiments, the isolation trench may be formed to expose the first conductive type semiconductor layer 343a. The hole h5 may be formed together with the isolation trench by etching technology, etc., but is not limited thereto.

[0495] The holes h1, h2, h3, h4, h5 and the isolation trenches may be formed by photolithography and etching techniques, and the order of formation is not particularly limited. For example, a shallower hole may be formed before a deeper hole, or vice versa. The isolation trench may be formed after or before the holes h1, h2, h3, h4, h5 are formed. Alternatively, as described above, the isolation trench may be formed together with the hole h5.

[0496] Reference Fig.46A and Fig.46B , a lower insulating layer 361 is formed on the first substrate 321. The lower insulating layer 361 may cover the side surface of the first substrate 321 exposed by the isolation trench and the side surfaces of the first LED stack 323, the second LED stack 333, and the third LED stack 343.

[0497] The lower insulating layer 361 may also cover the side surfaces of the holes h1, h2, h3, h4, h5. The lower insulating layer 361 is subjected to patterning to expose the bottom of each of the holes h1, h2, h3, h4, h5.

[0498] The lower insulating layer 361 may be formed of silicon oxide or silicon nitride, but the inventive concept is not limited thereto. The lower insulating layer 361 may be a distributed Bragg reflector.

[0499] Subsequently, through-hole vias 363b, 365a, 365b, 367a, 367b are formed in the holes h1, h2, h3, h4, h5. The through-hole vias 363b, 365a, 365b, 367a, 367b may be formed by electroplating or the like. For example, a seed layer may be first formed inside the holes h1, h2, h3, h4, h5, and the through-hole vias 363b, 365a, 365b, 367a, 367b may be formed by plating copper using the seed layer. The seed layer may be formed of, for example, Ni / Al / Ti / Cu.

[0500] Reference Fig.47A and Fig.47B , the upper surface of the first substrate 321 may be exposed by patterning the lower insulating layer 361. When the lower insulating layer 361 is patterned to expose the bottoms of the holes h1, h2, h3, h4, and h5, a process of patterning the lower insulating layer 361 to expose the upper surface of the first substrate 321 may be performed.

[0501] A substantial portion of the upper surface of the first substrate 321 may be exposed, for example, at least half of the area of ​​the light emitting device.

[0502] Thereafter, an ohmic electrode 363a is formed on the exposed upper surface of the first substrate 321. For example, the ohmic electrode 363a may be formed of a conductive layer such as Au-Te alloy or Au-Ge alloy, and make ohmic contact with the first substrate 321.

[0503] like Fig.47A As shown, the ohmic electrode 363a is isolated from the through-hole vias 363b, 365a, 365b, 367a, 367b.

[0504] Reference Fig.48A and Fig.48B , an upper insulating layer 371 is formed to cover the lower insulating layer 361 and the ohmic electrode 363a. The upper insulating layer 371 may also cover the lower insulating layer 361 at the side surface of the first LED stack 323, the side surface of the second LED stack 333, the side surface of the third LED stack 343, and the side surface of the first substrate 321. The upper insulating layer 371 may be patterned to form openings exposing the through-hole vias 363b, 365a, 365b, 367a, 367b and an opening 371a exposing the ohmic electrode 363a.

[0505] The upper insulating layer 371 may be formed of a transparent oxide layer such as silicon oxide or silicon nitride, but the inventive concept is not limited thereto. For example, the upper insulating layer 371 may be a light reflecting insulating layer such as a distributed Bragg reflector, or a light blocking layer such as a light absorbing layer.

[0506] Reference Fig.49A and Fig.49B , electrode pads 373a, 373b, 373c, 373d are formed on the upper insulating layer 371. The electrode pads 373a, 373b, 373c, 373d may include a first electrode pad 373a, a second electrode pad 373b, a third electrode pad 373c, and a common electrode pad 373d.

[0507] The first electrode pad 373a may be connected to the ohmic electrode 363a exposed through the opening 371a of the upper insulating layer 371, the second electrode pad 373b may be connected to the through-hole via 365a, and the third electrode pad 373c may be connected to the through-hole via 367a. The common electrode pad 373d may be commonly connected to the through-hole vias 363b, 365b, and 367b.

[0508] The electrode pads 373a, 373b, 373c, 373d are electrically isolated from each other, and thus, each of the first LED stack 323, the second LED stack 333, and the third LED stack 343 is electrically connected to two electrode pads to be independently driven.

[0509] Thereafter, the second substrate 341 is divided into regions for each light emitting device, thereby completing the light emitting device 300. Fig.49A As shown, electrode pads 373a, 373b, 373c, 373d may be disposed at four corners of each light emitting device 300. The electrode pads 373a, 373b, 373c, 373d may have a substantially rectangular shape, but the inventive concept is not limited thereto.

[0510] Although the second substrate 341 is described as being divided, in some exemplary embodiments, the second substrate 341 may be removed. In this case, the exposed surface of the first conductive type semiconductor layer 343 may be subjected to texturing.

[0511] Fig.50A and Fig.50B 3 and 4 are respectively a schematic plan view and a cross-sectional view of a light emitting device 302 for a display according to another exemplary embodiment.

[0512] Reference Fig.50A and Fig.50B , except that the anodes of the first to third LED stacks 323, 333, 343 are independently connected to the first to third electrode pads 3173a, 3173b, 3173c and the cathodes of the first to third LED stacks 323, 333, 343 are electrically connected to the common electrode pad 3173d, the light emitting device 302 according to the exemplary embodiment is different from the reference Fig.38A and Fig.38B The described light emitting device 300 is substantially similar.

[0513] More specifically, the first electrode pad 3173a is electrically connected to the first transparent electrode 325 through the through-hole via 3163b, the second electrode pad 3173b is electrically connected to the second transparent electrode 335 through the through-hole via 3165b, and the third electrode pad 3173c is electrically connected to the third transparent electrode 345 through the through-hole via 3167b. The common electrode pad 3173d is electrically connected to the ohmic electrode 3163a exposed through the opening 371a of the upper insulating layer 371, and is also electrically connected to the first conductive semiconductor layer 333a of the second LED stack 333 and the first conductive semiconductor layer 343a of the third LED stack 343 through the through-hole vias 3165a and 3167a. For example, the through-hole via 3165a may be connected to the first conductive semiconductor layer 333a, and the through-hole via 3175a may be connected to the ohmic electrode 346 that is in ohmic contact with the first conductive semiconductor layer 343a.

[0514] Each of the light emitting devices 300, 302 according to the exemplary embodiment includes a first LED stack 323, a second LED stack 333, and a third LED stack 343 that emit red light, green light, and blue light, respectively, and thus can be used as a pixel in a display device. Fig.37 As described, a display device can be implemented by arranging a plurality of light-emitting devices 300 or 302 on a circuit board 301. Since each of the light-emitting devices 300, 302 includes a first LED stack 323, a second LED stack 333, and a third LED stack 343, the area of ​​a sub-pixel in one pixel can be increased. In addition, the first LED stack 323, the second LED stack 333, and the third LED stack 343 can be mounted on the circuit board by mounting one light-emitting device, thereby reducing the number of mounting processes.

[0515] like Fig.37 As described, the light emitting device mounted on the circuit board 301 may be driven in a passive matrix driving manner or an active matrix driving manner.

[0516] Fig.51 is a schematic plan view of a display device according to an exemplary embodiment.

[0517] Reference Fig.51 , a display apparatus according to an exemplary embodiment includes a circuit board 401 and a plurality of light emitting devices 400 .

[0518] Circuit board 401 may include circuits for passive matrix driving or active matrix driving. In an exemplary embodiment, circuit board 401 may include interconnects and resistors. In another exemplary embodiment, circuit board 401 may include interconnects, transistors, and capacitors. Circuit board 401 may also have electrode pads disposed on its upper surface to allow electrical connection to the circuits therein.

[0519] The light emitting device 400 is arranged on the circuit board 401. Each light emitting device 400 may constitute a pixel. The light emitting device 400 may include electrode pads 473a, 473b, 473c, and 473d electrically connected to the circuit board 401. In addition, the light emitting device 400 may include a substrate 441 disposed at the upper surface thereof. Since the light emitting devices 400 are isolated from each other, the substrate 441 disposed at the upper surface of the light emitting device 400 is also isolated from each other.

[0520] Will refer to Fig.52A and Fig.52B The details of the light emitting device 400 are described. Fig.52A is a schematic plan view of a light emitting device 400 for a display according to an exemplary embodiment, Fig.52B It is along Fig.52A Although the electrode pads 473a, 473b, 473c and 473d are shown and described as being disposed on the upper side of the light emitting device, in some exemplary embodiments, the light emitting device 400 may be flip-chip bonded on the circuit board 401, in which case the electrode pads 473a, 473b, 473c and 473d may be disposed on the lower side thereof.

[0521] Reference Fig.52A and Fig.52B The light emitting device 400 may include a first substrate 421, a second substrate 441, a distributed Bragg reflector 422, a first LED stack 423, a second LED stack 433, a third LED stack 443, a first transparent electrode 425, a second transparent electrode 435, a third transparent electrode 445, an ohmic electrode 446, a first current diffuser 428, a second current diffuser 438, a third current diffuser 448, a first color filter 447, a second color filter 457, a first bonding layer 449, a second bonding layer 459, a lower insulating layer 461, an upper insulating layer 471, an ohmic electrode 463a, through-hole passages 463b, 465a, 465b, 467a and 467b, a heat pipe 469, and electrode pads 473a, 473b, 473c and 473d.

[0522] The first substrate 421 may support the LED stacks 423, 433, and 443. The first substrate 421 may be a growth substrate, for example, a GaAs substrate, for growing the first LED stack 423. Specifically, the first substrate 421 may have conductivity.

[0523] The second substrate 441 may support the LED stacks 423, 433, and 443. The LED stacks 423, 433, and 443 are disposed between the first substrate 421 and the second substrate 441. The second substrate 441 may be a growth substrate for growing the third LED stack 443. For example, the second substrate 441 may be a sapphire substrate or a GaN substrate, more specifically, a patterned sapphire substrate. The first LED stack, the second LED stack, and the third LED stack are disposed on the second substrate 441 in the order of the third LED stack 443, the second LED stack 433, and the first LED stack 423 from the second substrate 441. In an exemplary embodiment, a single third LED stack may be disposed on a single second substrate 441. The second LED stack 433, the first LED stack 423, and the first substrate 421 are disposed on the third LED stack 443. Therefore, the light emitting device 400 may have a single chip structure of a single pixel.

[0524] In another exemplary embodiment, a plurality of third LED stacks 43 may be disposed on a single second substrate 441. The second LED stack 433, the first LED stack 423, and the first substrate 421 are disposed on each third LED stack 43, and thus the light emitting device 400 has a single chip structure of a plurality of pixels.

[0525] In some exemplary embodiments, the second substrate 441 may be omitted, and the lower surface of the third LED stack 443 may be exposed. In this case, a roughened surface may be formed on the lower surface of the third LED stack 443 by surface texturing.

[0526] Each of the first LED stack 423, the second LED stack 433, and the third LED stack 443 includes a first conductive semiconductor layer 423a, 433a, and 443a, a second conductive semiconductor layer 423b, 433b, and 443b, and an active layer disposed between the first conductive semiconductor layer 423a, 433a, and 443a and the second conductive semiconductor layer 423b, 433b, and 443b, respectively. The active layer may have a multi-quantum well structure.

[0527] The LED stack may emit light of shorter wavelength as it is arranged closer to the second substrate 441. For example, the first LED stack 423 may be an inorganic light emitting diode suitable for emitting red light, the second LED stack 433 may be an inorganic light emitting diode suitable for emitting green light, and the third LED stack 443 may be an inorganic light emitting diode suitable for emitting blue light. The first LED stack 423 may include an AlGaInP-based well layer, the second LED stack 433 may include an AlGaInP-based well layer or an AlGaInN-based well layer, and the third LED stack 443 may include an AlGaInN-based well layer. However, the inventive concept is not limited thereto. When the light emitting device 400 includes a micro-LED having a surface area of ​​less than about 10,000 square microns, or less than about 4,000 square microns or 2,500 square microns in other exemplary embodiments as known in the art, the first LED stack 423 can emit any one of red, green, and blue light, and the second LED stack 433 and the third LED stack 443 can emit different ones of red, green, and blue light without negatively affecting operation due to the small form factor of the micro-LED.

[0528] In addition, the first conductive semiconductor layer 423a, 433a, and 443a of each of the LED stacks 423, 433, and 443 may be an n-type semiconductor layer, and the second conductive semiconductor layer 423b, 433b, and 443b of each of the LED stacks 423, 433, and 443 may be a p-type semiconductor layer. In the illustrated exemplary embodiment, the upper surface of the first LED stack 423 is an n-type semiconductor layer 423a, the upper surface of the second LED stack 433 is an n-type semiconductor layer 433a, and the upper surface of the third LED stack 443 is a p-type semiconductor layer 443b. Specifically, only the semiconductor layers of the third LED stack 443 are stacked in an order different from that of the first LED stack 423 and the second LED stack 433. The first conductive semiconductor layer 443a of the third LED stack 443 may be subjected to surface texturing to improve light extraction efficiency. In some exemplary embodiments, the first conductive semiconductor layer 433a of the second LED stack 433 may also be subjected to surface texturing.

[0529] The first LED stack 423, the second LED stack 433, and the third LED stack 443 may be stacked to overlap each other and may have substantially the same light emitting area. In addition, in each of the LED stacks 423, 433, and 443, the first conductive semiconductor layers 423a, 433a, and 443a may have substantially the same area as the second conductive semiconductor layers 423b, 433b, and 443b, respectively. Specifically, in each of the first LED stack 423 and the second LED stack 433 according to the exemplary embodiment, the first conductive semiconductor layer 423a or 433a may completely overlap the second conductive semiconductor layer 423b or 433b. In the third LED stack 443, a hole h5 is formed on the second conductive semiconductor layer 443b to expose the first conductive semiconductor layer 443a, and therefore, the first conductive semiconductor layer 443a has a slightly larger area than the second conductive semiconductor layer 443b.

[0530] The first LED stack 423 is disposed away from the second substrate 441, the second LED stack 433 is disposed below the first LED stack 423, and the third LED stack 443 is disposed below the second LED stack 433. Since the wavelength of light emitted by the first LED stack 423 may be longer than the wavelengths of light emitted by the second LED stack 433 and the third LED stack 443, light generated from the first LED stack 423 may be emitted to the outside after passing through the second LED stack 433, the third LED stack 443, and the second substrate 441. In addition, since the wavelength of light emitted by the second LED stack 433 may be longer than the wavelength of light emitted by the third LED stack 443, light generated from the second LED stack 433 may be emitted to the outside after passing through the third LED stack 443 and the second substrate 441.

[0531] The distributed Bragg reflector 422 may be disposed between the first substrate 421 and the first LED stack 423. The distributed Bragg reflector 422 reflects light generated from the first LED stack 423 to prevent the light from being lost by absorption by the substrate 421. For example, the distributed Bragg reflector 422 may be formed by alternately stacking AlAs-based semiconductor layers and AlGaAs-based semiconductor layers on each other.

[0532] The first transparent electrode 425 may be disposed between the first LED stack 423 and the second LED stack 433. The first transparent electrode 425 makes ohmic contact with the second conductive semiconductor layer 423b of the first LED stack 423 and transmits light generated from the first LED stack 423. The first transparent electrode 425 may include a metal layer or a transparent oxide layer (e.g., an indium tin oxide (ITO) layer, etc.).

[0533] The second transparent electrode 435 makes ohmic contact with the second conductive semiconductor layer 433b of the second LED stack 433. As shown in the figure, the second transparent electrode 435 contacts the lower surface of the second LED stack 433 between the second LED stack 433 and the third LED stack 443. The second transparent electrode 435 may include a metal layer or a conductive oxide layer transparent to red and green light.

[0534] The third transparent electrode 445 is in ohmic contact with the second conductive semiconductor layer 443b of the third LED stack 443. The third transparent electrode 445 may be disposed between the second LED stack 433 and the third LED stack 443 and contact the upper surface of the third LED stack 443. The third transparent electrode 445 may include a metal layer or a conductive oxide layer transparent to red light and green light. The third transparent electrode 445 may also be transparent to blue light. Each of the second transparent electrode 435 and the third transparent electrode 445 is in ohmic contact with the p-type semiconductor layer of each LED stack to facilitate current diffusion. Examples of the conductive oxide layer for the second transparent electrode 435 and the third transparent electrode 445 may include SnO2, InO2, ITO, ZnO, IZO, etc.

[0535] The first current spreader 428, the second current spreader 438, and the third current spreader 448 may be provided to spread the current in the second conductive semiconductor layer 423b of the first LED stack 423, the second conductive semiconductor layer 433b of the second LED stack 433, and the second conductive semiconductor layer 443b of the third LED stack 443. As shown in the figure, the first current spreader 428 may be provided on the second conductive semiconductor layer 423b exposed by the first transparent electrode 425, the second current spreader 438 may be provided on the second conductive semiconductor layer 433b exposed by the second transparent electrode 435, and the third current spreader 448 may be provided on the second conductive semiconductor layer 443b exposed by the third transparent electrode 445. Fig.52A As shown, each of the first current spreader 428, the second current spreader 438, and the third current spreader 448 may be disposed along the edge of each of the first LED stack 423, the second LED stack 433, and the third LED stack 443. In addition, each of the first current spreader 428, the second current spreader 438, and the third current spreader 448 may have a substantially rectangular shape to surround the center of each LED stack, but the inventive concept is not limited thereto, and the current spreader may have various shapes, such as a substantially extended line or curved line shape. In addition, the first current spreader 428, the second current spreader 438, and the third current spreader 448 may be disposed to overlap each other, but are not limited thereto.

[0536] The first current spreader 428, the second current spreader 438, and the third current spreader 448 may be isolated from the first transparent electrode 425, the second transparent electrode 435, and the third transparent electrode 445. Therefore, gaps may be formed between the side surface of the first current spreader 428 and the side surface of the first transparent electrode 425, between the side surface of the second current spreader 438 and the side surface of the second transparent electrode 435, and between the side surface of the third current spreader 448 and the side surface of the third transparent electrode 445. However, the inventive concept is not limited thereto, and at least one of the first current spreader 428, the second current spreader 438, and the third current spreader 448 may contact the first transparent electrode 425, the second transparent electrode 435, and the third transparent electrode 445.

[0537] The first current spreader 428, the second current spreader 438, and the third current spreader 448 may be formed of a material having higher conductivity than the first transparent electrode 425, the second transparent electrode 435, and the third transparent electrode 445, and thus current may be uniformly spread over a wide area of ​​the second conductive semiconductor layers 423b, 433b, and 443b.

[0538] The ohmic electrode 446 is in ohmic contact with the first conductive semiconductor layer 443a of the third LED stack 443. The ohmic electrode 446 may be disposed on the first conductive semiconductor layer 443a exposed by the third transparent electrode 445 and the second conductive semiconductor layer 443b. For example, the ohmic electrode 446 may be formed of Ni / Au / Ti or Ni / Au / Ti / Ni. When the surface of the ohmic electrode 446 is exposed during the etching process, a Ni layer may be formed on the surface of the ohmic electrode 446 to serve as an etching stop layer. The ohmic electrode 446 may be formed to have various shapes, and specifically, the ohmic electrode 446 may be formed to have a substantially elongated shape to serve as a current diffuser. In some exemplary embodiments, the ohmic electrode 446 may be omitted.

[0539] The first color filter 447 may be disposed between the third transparent electrode 445 and the second LED stack 433, and the second color filter 457 may be disposed between the second LED stack 433 and the first LED stack 423. The first color filter 447 transmits light generated from the first LED stack 423 and the second LED stack 433, while reflecting light generated from the third LED stack 443. The second color filter 457 transmits light generated from the first LED stack 423, while reflecting light generated from the second LED stack 433. Therefore, light generated from the first LED stack 423 may be emitted to the outside through the second LED stack 433 and the third LED stack 443, and light generated from the second LED stack 433 may be emitted to the outside through the third LED stack 443. In addition, light loss may be prevented by preventing light generated from the second LED stack 433 from entering the first LED stack 423 or preventing light generated from the third LED stack 443 from entering the second LED stack 433.

[0540] In some exemplary embodiments, the second color filter 457 may reflect light generated from the third LED stack 443 .

[0541] The first color filter 447 and the second color filter 457 can be, for example, a low-pass filter that allows light in a low frequency band (e.g., in a long wave band) to pass through it, a band-pass filter that allows light in a predetermined wave band to pass through it, or a band-stop filter that prevents light in a predetermined wave band from passing through it. Specifically, for example, each of the first color filter 447 and the second color filter 457 can be formed by alternately stacking insulating layers (such as TiO2 and SiO2) with different refractive indices on top of each other. Specifically, each of the first color filter 447 and the second color filter 457 can include a distributed Bragg reflector (DBR). In addition, the stop band of the distributed Bragg reflector can be controlled by adjusting the thickness of the TiO2 layer and the thickness of the SiO2 layer. Low-pass filters and band-pass filters can also be formed by alternately stacking insulating layers with different refractive indices on top of each other.

[0542] The first bonding layer 449 bonds the second LED stack 433 to the third LED stack 443. The first bonding layer 449 may bond the first color filter 447 to the second transparent electrode 435 between the first color filter 447 and the second transparent electrode 435. For example, the first bonding layer 449 may be formed of a transparent organic material or a transparent inorganic material. Examples of organic materials may include SU8, poly(methyl methacrylate) (PMMA), polyimide, polyparaxylene, benzocyclobutene (BCB), etc., and examples of inorganic materials may include Al2O3, SiO2, SiN x Etc. More specifically, the first bonding layer 449 may be formed of spin-on glass (SOG).

[0543] The second bonding layer 459 bonds the second LED stack 433 to the first LED stack 423. As shown, the second bonding layer 459 may be disposed between the second color filter 457 and the first transparent electrode 425. The second bonding layer 459 may be formed of substantially the same material as the first bonding layer 449.

[0544] Holes h1, h2, h3, h4, and h5 are formed through the first substrate 421. The hole h1 may be formed through the first substrate 421, the distributed Bragg reflector 422, and the first LED stack 423 to expose the first transparent electrode 425. The hole h2 may be formed through the first substrate 421, the distributed Bragg reflector 422, the first transparent electrode 425, the second bonding layer 459, and the second color filter 457 to expose the first conductive type semiconductor layer 433a of the second LED stack 433.

[0545] A hole h3 may be formed through the first substrate 421, the distributed Bragg reflector 422, the first transparent electrode 425, the second bonding layer 459, the second color filter 457, and the second LED stack 433 to expose the second transparent electrode 435. A hole h4 may be formed through the first substrate 421, the distributed Bragg reflector 422, the first transparent electrode 425, the second bonding layer 459, the second color filter 457, the second LED stack 433, the second transparent electrode 435, the first bonding layer 449, and the first color filter 447 to expose the third transparent electrode 445. In addition, a hole h5 may be formed through the first substrate 421, the distributed Bragg reflector 422, the first transparent electrode 425, the second bonding layer 459, the second color filter 457, the second LED stack 433, the second transparent electrode 435, the first bonding layer 449, and the first color filter 447 to expose the ohmic electrode 446. When the ohmic electrode 446 is omitted in some exemplary embodiments, the first conductive type semiconductor layer 443 a may be exposed by the hole h5 .

[0546] Although the holes h1, h3, and h4 are shown to be isolated from each other to expose the first, second, and third transparent electrodes 425, 435, and 445, respectively, the inventive concept is not limited thereto, and the first, second, and third transparent electrodes 425, 435, and 445 may be exposed through a single hole.

[0547] In addition, the first to third transparent electrodes 425 , 435 , and 445 are illustrated as being exposed through the holes h1 , h3 , and h4 , but in some exemplary embodiments, the first to third current spreaders 428 , 438 , and 448 may be exposed.

[0548] The lower insulating layer 461 covers the side surfaces of the first substrate 421 and the side surfaces of the first LED stack 423, the second LED stack 433, and the third LED stack 443, while covering the upper surface of the first substrate 421. The lower insulating layer 461 also covers the side surfaces of the holes h1, h2, h3, h4, and h5. However, the lower insulating layer 461 may be patterned to expose the bottom of each of the holes h1, h2, h3, h4, and h5. In addition, the lower insulating layer 461 may also be patterned to expose the upper surface of the first substrate 421.

[0549] The ohmic electrode 463a is in ohmic contact with the upper surface of the first substrate 421. The ohmic electrode 463a may be formed in an exposed region of the first substrate 421 exposed by patterning the lower insulating layer 461. For example, the ohmic electrode 463a may be formed of an Au-Te alloy or an Au-Ge alloy. Each of the through-hole paths 463b, 465b, and 467b may be connected to the first transparent electrode 425, the second transparent electrode 435, and the third transparent electrode 445, and may be connected to the first current spreader 428, the second current spreader 438, and the third current spreader 448.

[0550] The through-hole vias 463b, 465a, 465b, 467a and 467b are disposed in the holes h1, h2, h3, h4 and h5. The through-hole via 463b may be disposed in the hole h1 and may be connected to the first transparent electrode 425. The through-hole via 465a may be disposed in the hole h2 and may be in ohmic contact with the first conductive semiconductor layer 433a. The through-hole via 465b may be disposed in the hole h3 and may be electrically connected to the second transparent electrode 435. The through-hole via 467a may be disposed in the hole h5 and may be electrically connected to the first conductive semiconductor layer 443a. For example, the through-hole via 467a may be electrically connected to the ohmic electrode 445 through the hole h5. The through-hole via 467b may be disposed in the hole h4 and may be connected to the third transparent electrode 445. The through-hole vias 463 b , 465 b , and 467 b may be connected to the first, second, and third transparent electrodes 425 , 435 , and 445 , or may be connected to the first, second, and third current spreaders 428 , 438 , and 448 .

[0551] The through hole vias 463b, 465a, 465b, 467a, and 467b may be isolated and insulated from the substrate 421 by the lower insulating layer 461 inside the hole. The through hole vias 463b, 465a, 465b, 467a, and 467b may pass through the substrate 421 and may also pass through the distributed Bragg reflector 422.

[0552] At least a portion of each heat pipe 469 is disposed inside the substrate 421. Specifically, the heat pipe 469 may be disposed above the first LED stack 423 and may be disposed on the distributed Bragg reflector 422. The heat pipe 469 may contact the distributed Bragg reflector 422, or may be isolated from the distributed Bragg reflector 422. Since the heat pipe 469 is disposed on the distributed Bragg reflector 422, the distributed Bragg reflector 422 is not damaged by the heat pipe 469, and thus, a reduction in the reflectivity of the distributed Bragg reflector 422 caused by the heat pipe 469 may be prevented. However, the inventive concept is not limited thereto, and a portion of the heat pipe 469 may be disposed in the distributed Bragg reflector 422.

[0553] like Fig.52B As shown, the heat pipe 469 may be connected to the ohmic electrode 463a. However, the inventive concept is not limited thereto, and the heat pipe 469 may be isolated from the ohmic electrode 463a. In addition, the upper surface of the heat pipe 469 may be substantially flush with the upper surface of the substrate 421, but in some exemplary embodiments, the upper surface of the heat pipe 469 may protrude above the upper surface of the substrate 421.

[0554] The upper insulating layer 471 covers the lower insulating layer 461 and the ohmic electrode 463a. The upper insulating layer 471 may cover the lower insulating layer 461 at the sides of the first substrate 421, the first LED stack 423, the second LED stack 433, and the third LED stack 443. The top surface of the lower insulating layer 461 may be covered by the upper insulating layer 471. The upper insulating layer 471 may have an opening 471a for exposing the ohmic electrode 463a, and may have an opening for exposing the through-hole vias 463b, 465a, 465b, 467a, and 467b.

[0555] The upper insulating layer 471 may cover the upper portion of the heat pipe 469 , but in some exemplary embodiments, the upper insulating layer 471 may expose the upper surface of the heat pipe 469 .

[0556] The lower insulating layer 461 or the upper insulating layer 471 may be formed of silicon oxide or silicon nitride, but is not limited thereto. For example, the lower insulating layer 461 or the upper insulating layer 471 may be a distributed Bragg reflector formed by stacking insulating layers having different refractive indices. Specifically, the upper insulating layer 471 may be a light reflecting layer or a light blocking layer.

[0557] The electrode pads 473a, 473b, 473c, and 473d are disposed on the upper insulating layer 471 and are electrically connected to the first LED stack 423, the second LED stack 433, and the third LED stack 443. For example, the first electrode pad 473a is electrically connected to the ohmic electrode 463a exposed through the opening 471a of the upper insulating layer 471, and the second electrode pad 473b is electrically connected to the through-hole via 465a exposed through the opening of the upper insulating layer 471. In addition, the third electrode pad 473c is electrically connected to the through-hole via 467a exposed through the opening of the upper insulating layer 471. The common electrode pad 473d is electrically connected to the through-hole vias 463b, 465b, and 467b in common.

[0558] Therefore, the common electrode pad 473d is electrically connected to the second conductive semiconductor layer 423b of the first LED stack 423, the second conductive semiconductor layer 433b of the second LED stack 433, and the second conductive semiconductor layer 443b of the third LED stack 443, and each of the electrode pads 473a, 473b and 473c is electrically connected to the first conductive semiconductor layer 423a of the first LED stack 423, the first conductive semiconductor layer 433a of the second LED stack 433, and the first conductive semiconductor layer 443a of the third LED stack 443, respectively.

[0559] According to the exemplary embodiment shown, the first LED stack 423 is electrically connected to the electrode pads 473d and 473a, the second LED stack 433 is electrically connected to the electrode pads 473d and 473b, and the third LED stack 443 is electrically connected to the electrode pads 473d and 473c. In this way, the anode of the first LED stack 423, the anode of the second LED stack 433, and the anode of the third LED stack 443 are electrically connected to the electrode pad 473d, and the cathode of the first LED stack 423, the cathode of the second LED stack 433, and the cathode of the third LED stack 443 are electrically connected to the first electrode pad 473a, the second electrode pad 473b, and the third electrode pad 473c, respectively. Therefore, the first LED stack 423, the second LED stack 433, and the third LED stack 443 can be driven independently.

[0560] The heat pipe 469 may be electrically connected to the first electrode pad 473a through the ohmic electrode 463a. In some exemplary embodiments, a portion of the heat pipe 469 may be disposed in a lower region of the first electrode pad 473a.

[0561] Fig.53A , Fig.53B , Fig.54A , Fig.54B , Fig.55A , Fig.55B , Fig.56 , Fig.57 , Fig.58 , Fig.59A , Fig.59B , Fig.60A , Fig.60B , Fig.61A , Fig.61B , Fig.62A , Fig.62B , Fig.63A , Fig.63B , Fig.64A , Fig.64B , Fig.65A and Fig.65B Schematic plan view and cross-sectional view showing a method of manufacturing a light emitting device for a display according to an exemplary embodiment of the present disclosure. In the figure, each plan view corresponds to Fig.52A , each cross-sectional view is taken along line AA of the corresponding plan view. Fig.53B and Fig.54B Along the Fig.53A and Fig.54A A cross-sectional view taken along line BB.

[0562] First, refer to Fig.53A and Fig.53B , a first LED stack 423 is grown on a first substrate 421. For example, the first substrate 421 may be a GaAs substrate. In addition, the first LED stack 423 may include a semiconductor layer based on AlGaInP, and include a first conductive type semiconductor layer 423a, an active layer, and a second conductive type semiconductor layer 423b. The first conductive type may be an n-type, and the second conductive type may be a p-type. A distributed Bragg reflector 422 may be formed before growing the first LED stack 423. The distributed Bragg reflector 422 may have a stacked structure formed by repeatedly stacking, for example, AlAs / AlGaAs layers.

[0563] A first transparent electrode 425 may be formed on the second conductive type semiconductor layer 423b. The first transparent electrode 425 may be formed of a transparent oxide layer such as indium tin oxide (ITO), a transparent metal layer, or the like.

[0564] The first transparent electrode 425 may be formed to have an opening for exposing the second conductive semiconductor layer 423b, and the first current spreader 428 may be formed in the opening. The first transparent electrode 425 may be patterned by, for example, photolithography and etching techniques, which may form an opening for exposing the second conductive semiconductor layer 423b. The opening of the first transparent electrode 425 may define a region in which the first current spreader 428 may be formed.

[0565] although Fig.53AThe first current spreader 428 is shown as having a substantially rectangular shape, but the inventive concept is not limited thereto. For example, the first current spreader 428 may have various shapes, such as a substantially extended line or curved line shape. The first current spreader 428 may be formed by a lift-off technique, etc., and a side of the first current spreader 428 may be isolated from the first transparent electrode 425. The first current spreader 428 may be formed to have the same or similar thickness as the first transparent electrode 425.

[0566] Reference Fig.54A and Fig.54B , a second LED stack 433 is grown on the substrate 431, and a second transparent electrode 435 is formed on the second LED stack 433. The second LED stack 433 may include a semiconductor layer based on AlGaInP or a semiconductor layer based on AlGaInN, and may include a first conductive type semiconductor layer 433a, an active layer, and a second conductive type semiconductor layer 433b. The substrate 431 may be a substrate on which a semiconductor layer based on AlGaInP can be grown, such as a GaAs substrate or a GaP substrate, or a substrate on which a semiconductor layer based on AlGaInN can be grown, such as a sapphire substrate. The first conductive type may be an n-type, and the second conductive type may be a p-type. The composition ratio of Al, Ga, and In for the second LED stack 433 may be determined so that the second LED stack 433 may emit, for example, green light. In addition, when a GaP substrate is used, a pure GaP layer or a GaP layer doped with nitrogen (N) is formed on the GaP to emit green light. The second transparent electrode 435 is in ohmic contact with the second conductive type semiconductor layer 433b. The second transparent electrode 435 may be formed of a metal layer or a conductive oxide layer such as SnO 2 , InO 2 , ITO, ZnO, IZO, or the like.

[0567] The second transparent electrode 435 may be formed to have an opening for exposing the second conductive semiconductor layer 433b, and the second current spreader 438 may be formed in the opening. The second transparent electrode 435 may be patterned by, for example, photolithography and etching techniques, which may form an opening for exposing the second conductive semiconductor layer 433b. The opening of the second transparent electrode 435 may define a region in which the second current spreader 438 may be formed.

[0568] although Fig.54A The second current spreader 438 is shown as having a substantially rectangular shape, but the inventive concept is not limited thereto. For example, the second current spreader 438 may have various shapes, such as a substantially extended line or curved line shape. The second current spreader 438 may be formed by a lift-off technique, etc., and its side may be isolated from the second transparent electrode 435. The second current spreader 438 may be formed to have the same or similar thickness as the second transparent electrode 435.

[0569] The second current spreader 438 may have substantially the same shape and the same size as the first current spreader 428 , but the inventive concept is not limited thereto.

[0570] Reference Fig.55A and Fig.55B , a third LED stack 443 is grown on the second substrate 441, and a third transparent electrode 445 is formed on the third LED stack 443. The third LED stack 443 may include an AlGaInN-based semiconductor layer, and may include a first conductive type semiconductor layer 443a, an active layer, and a second conductive type semiconductor layer 443b. The first conductive type may be an n-type, and the second conductive type may be a p-type.

[0571] The second substrate 441 is a substrate on which a GaN-based semiconductor layer can be grown, and may be different from the first substrate 421. The composition ratio of AlGaInN for the third LED stack 443 is determined so that the third LED stack 443 emits, for example, blue light. The third transparent electrode 445 is in ohmic contact with the second conductive semiconductor layer 443b. The third transparent electrode 445 may be formed of a conductive oxide layer such as SnO2, InO2, ITO, ZnO, IZO, or the like.

[0572] The third transparent electrode 445 may be formed to have an opening for exposing the first conductive type semiconductor layer 443a and an opening for exposing the second conductive type semiconductor layer 443b. The opening for exposing the first conductive type semiconductor layer 443a may define a region where the ohmic electrode 446 may be formed, and the opening for exposing the second conductive type semiconductor layer 443b may define a region where the third current spreader 448 may be formed.

[0573] The third transparent electrode 445 may be patterned by, for example, photolithography and etching techniques, which may form an opening for exposing the second conductive semiconductor layer 443b. Subsequently, the first conductive semiconductor layer 443a may be exposed by partially etching the second conductive semiconductor layer 443b, and an ohmic electrode 446 may be formed in the exposed region of the first conductive semiconductor layer 443a. The ohmic electrode 446 may be formed by a metal layer and in ohmic contact with the first conductive semiconductor layer 443a. For example, the ohmic electrode 446 may be formed by a multilayer structure of Ni / Au / Ti or Ni / Au / Ti / Ni. The ohmic electrode 446 is electrically isolated from the third transparent electrode 445 and the second conductive semiconductor layer 443b.

[0574] A third current spreading member 448 is formed in the exposed region of the second conductive type semiconductor layer 443b. Fig.55AThe third current spreader 448 is shown to have a substantially rectangular shape, but the inventive concept is not limited thereto. For example, the third current spreader 448 may have various shapes, such as a substantially extended line or curved line shape. The third current spreader 448 may be formed by a lift-off technique, etc., and a side of the third current spreader 448 may be isolated from the third transparent electrode 445. The third current spreader 448 may be formed to have the same or similar thickness as the third transparent electrode 445.

[0575] The third current spreader 448 may have substantially the same shape and the same size as the first current spreader 428 or the second current spreader 438 , but the inventive concept is not limited thereto.

[0576] Then, a first color filter 447 is formed on the second transparent electrode 445. Fig.52A and Fig.52B The described first color filter 447 is substantially the same, so a detailed description thereof will be omitted to avoid redundancy.

[0577] Reference Fig.56 ,Will Fig.54A and Fig.54B The second LED stack 433 is bonded to Fig.55A and Fig.55B The third LED stack 443 is formed on the substrate 431 and the second substrate 431 is removed therefrom.

[0578] The first color filter 447 is bonded to the second transparent electrode 435 to face each other. For example, a bonding material layer may be formed on the first color filter 447 and the second transparent electrode 435, and bonded to each other to form a first bonding layer 449. For example, the bonding material layer may be a transparent organic material layer or a transparent inorganic material layer. Examples of organic materials may include SU8, poly(methyl methacrylate) (PMMA), polyimide, polyparaxylene, benzocyclobutene (BCB), etc., and examples of inorganic materials may include Al2O3, SiO2, SiN x Etc. More specifically, the first bonding layer 449 may be formed of spin-on glass (SOG).

[0579] The second current spreading member 438 may be disposed to overlap the third current spreading member 448 , but the present inventive concept is not limited thereto.

[0580] Thereafter, the substrate 431 may be removed from the second LED stack 433 by laser lift-off or chemical lift-off. In this way, the upper surface of the first conductive type semiconductor layer 433a of the second LED stack 433 is exposed. The exposed surface of the first conductive type semiconductor layer 433a may be subjected to texturing.

[0581] Reference Fig.57, a second color filter 457 is formed on the second LED stack 433. The second color filter 457 may be formed by alternately stacking insulating layers having different refractive indices and is aligned with the reference Fig.52A and Fig.52B The described second color filter 457 is substantially the same, and thus, a detailed description thereof will be omitted to avoid redundancy.

[0582] Then, refer to Fig.58 ,Will Fig.53A and Fig.53B The first LED stack 423 is bonded to the second LED stack 433. The second color filter 457 may be bonded to the first transparent electrode 425 to face each other. For example, a bonding material layer may be formed on the second color filter 457 and the first transparent electrode 425, and bonded to each other to form a second bonding layer 459. The bonding material layer is substantially the same as the bonding material layer described with reference to the first bonding layer 449, and therefore, a detailed description thereof will be omitted.

[0583] The first current spreader 428 may be disposed to overlap the second current spreader 438 or the third current spreader 448 , but the inventive concept is not limited thereto.

[0584] Reference Fig.59A and Fig.59B , holes h1 , h2 , h3 , h4 , and h5 are formed through the first substrate 421 , and isolation trenches defining a device region are formed to expose the first substrate 441 .

[0585] The hole h1 exposes the first transparent electrode 425, the hole h2 exposes the first conductive semiconductor layer 433a, the hole h3 exposes the second transparent electrode 435, the hole h4 exposes the third transparent electrode 445, and the hole h5 exposes the ohmic electrode 446. When the hole h5 exposes the ohmic electrode 446, the upper surface of the ohmic electrode 446 may include an anti-etching layer, such as a Ni layer. In an exemplary embodiment, the holes h1, h3, and h4 may expose the first current spreader 428, the second current spreader 438, and the third current spreader 448, respectively. In addition, the hole h5 may expose the first conductive semiconductor layer 443a.

[0586] The isolation trench may expose the second substrate 441 along the periphery of each of the first LED stack 423, the second LED stack 433, and the third LED stack 443. Although the isolation trench is shown as being formed to expose the second substrate 441 in the illustrated exemplary embodiment, in some exemplary embodiments, the isolation trench may be formed to expose the first conductive type semiconductor layer 443a. The hole h5 may be formed together with the isolation trench by an etching technique or the like, but the inventive concept is not limited thereto.

[0587] The holes h1, h2, h3, h4 and h5 and the isolation trenches can be formed by photolithography and etching techniques, but are not limited to a specific formation order. For example, a shallower hole can be formed before a deeper hole, or vice versa. The isolation trench can be formed before or after the holes h1, h2, h3, h4 and h5 are formed. Alternatively, as described above, the isolation trench can be formed together with the hole h5.

[0588] Reference Fig.60A and Fig.60B , a lower insulating layer 461 is formed on the first substrate 421. The lower insulating layer 461 may cover the side surface of the first substrate 421 exposed by the isolation trench and the side surfaces of the first LED stack 423, the second LED stack 433, and the third LED stack 443.

[0589] The lower insulating layer 461 may also cover the side surfaces of the holes h1, h2, h3, h4, and h5. The lower insulating layer 461 may be patterned to expose the bottom of each of the holes h1, h2, h3, h4, and h5. In addition, the lower insulating layer 461 may be patterned to expose the upper surface of the substrate 421. The first substrate 421 may be exposed to a relatively large area, for example, more than half of the area of ​​the light emitting device.

[0590] The process of exposing the bottoms of the holes h1 , h2 , h3 , h4 , and h5 and the process of exposing the upper surface of the substrate 421 may be performed in the same process or in separate processes.

[0591] The lower insulating layer 461 may be formed of silicon oxide or silicon nitride, but is not limited thereto. The lower insulating layer 461 may be a distributed Bragg reflector.

[0592] Reference Fig.61A and Fig.61B , a hole h6 is formed in the substrate 421. The hole h6 may be arranged to cross the substrate 421. Fig.61B As shown, the hole h6 may expose the distributed Bragg reflector 422 through the substrate 421, but the inventive concept is not limited thereto. For example, the bottom surface of the hole h6 is formed inside the substrate 421, so that the hole h6 may be isolated from the distributed Bragg reflector 422 and disposed above the distributed Bragg reflector 422. In another exemplary embodiment, the hole h6 may extend into the distributed Bragg reflector 422.

[0593] Reference Fig.62A and Fig.62B, through-hole passages 463b, 465a, 465b, 467a, and 467b are formed inside holes h1, h2, h3, h4, and h5, and a heat pipe 469 is formed inside hole h6. The through-hole passages 463b, 465a, 465b, 467a, and 467b and the heat pipe 469 may be formed by electroplating or the like. For example, a seed layer may be first formed inside holes h1, h2, h3, h4, h5, and h6, and the through-hole passages 463b, 465a, 465b, 467a, and 467b and the heat pipe 469 may be formed by copper plating using the seed layer. For example, the seed layer may be formed of Ni / Al / Ti / Cu.

[0594] In the exemplary embodiment shown, the through-hole passages 463b, 465a, 465b, 467a, and 467b are isolated from the substrate 421 by the lower insulating layer 461. However, the heat pipe 469 may contact the substrate 421 inside the substrate 421. Therefore, heat exchange may occur between the heat pipe 469 and the substrate 421, so that the heat generated in the LED stacks 423, 433, and 443 may be easily diffused into the substrate 421 and / or diffused to the outside.

[0595] Reference Fig.63A and Fig.63B , an ohmic electrode 463a is formed on the first substrate 421. The ohmic electrode 463a may be formed in an exposed region of the first substrate 421 exposed by patterning the lower insulating layer 461. The ohmic electrode 463a may be formed as a conductive layer in ohmic contact with the first substrate 421, and may be formed of, for example, an Au-Te alloy or an Au-Ge alloy.

[0596] like Fig.63A As shown, the ohmic electrode 463a may be isolated from the through-hole vias 463b, 465a, 465b, 467a, and 467b, and may cover the heat pipe 469. However, the inventive concept is not limited thereto, and the ohmic electrode 463a may be isolated from the heat pipe 469.

[0597] Reference Fig.64A and Fig.64B , an upper insulating layer 471 is formed to cover the lower insulating layer 461 and the ohmic electrode 463a. The upper insulating layer 471 may also cover the lower insulating layer 461 at the side surfaces of the first LED stack 423, the second LED stack 433, and the third LED stack 443 and the side surface of the first substrate 421. The upper insulating layer 471 may be patterned to form openings exposing the through-hole vias 463b, 465a, 465b, 467a, 467b and an opening 471a exposing the ohmic electrode 463a.

[0598] The upper insulating layer 471 may be formed of a transparent oxide layer such as silicon oxide or silicon nitride, but is not limited thereto. For example, the upper insulating layer 471 may be a light reflecting insulating layer such as a distributed Bragg reflector, or a light blocking layer such as a light absorbing layer.

[0599] Reference Fig.65A and Fig.65B , electrode pads 473a, 473b, 473c, and 473d are formed on the upper insulating layer 471. The electrode pads 473a, 473b, 473c, and 473d may include a first electrode pad 473a, a second electrode pad 473b, a third electrode pad 473c, and a common electrode pad 473d.

[0600] The first electrode pad 473a may be connected to the ohmic electrode 463a exposed through the opening 471a of the upper insulating layer 471, the second electrode pad 473b may be connected to the through-hole via 465a, and the third electrode pad 473c may be connected to the through-hole via 467a. The common electrode pad 473d may be commonly connected to the through-hole vias 463b, 465b, and 467b.

[0601] The electrode pads 473 a , 473 b , 473 c , and 473 d are electrically isolated from each other, and thus, each of the first LED stack 423 , the second LED stack 433 , and the third LED stack 443 is electrically connected to two electrode pads to be independently driven.

[0602] Thereafter, the second substrate 441 is divided into regions for each light emitting device, thereby completing the light emitting device 400. Fig.65A As shown, the electrode pads 473a, 473b, 473c, and 473d may be disposed near four corners of each light emitting device 400. In addition, the electrode pads 473a, 473b, 473c, and 473d may have a substantially rectangular shape, but the inventive concept is not limited thereto.

[0603] Although the second substrate 441 is illustrated as being divided, in some exemplary embodiments, the second substrate 441 may be removed. In this case, an exposed surface of the first conductive type semiconductor layer 443 may be subjected to texturing.

[0604] Fig.66A and Fig.66B are schematic plan views and cross-sectional views of a light emitting device 402 for a display according to another exemplary embodiment.

[0605] Reference Fig.66A and Fig.66B, except that the anode of the first LED stack 423, the anode of the second LED stack 433, and the anode of the third LED stack 443 are independently connected to the first electrode pad 4173a, the second electrode pad 4173b, and the third electrode pad 4173c, and the cathode of the first LED stack 423, the cathode of the second LED stack 433, and the cathode of the third LED stack 443 are electrically connected to the common electrode pad 4173d. Fig.52A and Fig.52B The described light emitting device 400 is substantially similar.

[0606] Specifically, the first electrode pad 4173a is electrically connected to the first transparent electrode 425 through the through-hole via 4163b, the second electrode pad 4173b is electrically connected to the second transparent electrode 435 through the through-hole via 4165b, and the third electrode pad 4173c is electrically connected to the third transparent electrode 445 through the through-hole via 4167b. The common electrode pad 4173d is electrically connected to the ohmic electrode 4163a exposed through the opening 471a of the upper insulating layer 471, and is also electrically connected to the first conductive semiconductor layer 433a of the second LED stack 433 and the first conductive semiconductor layer 443a of the third LED stack 443 through the through-hole vias 4165a and 4167a. For example, the through-hole via 4165a may be connected to the first conductive semiconductor layer 433a, and the through-hole via 4167a may be connected to the ohmic electrode 446 that is in ohmic contact with the first conductive semiconductor layer 443a.

[0607] Heat pipe 4169 is set as reference Fig.52A and Fig.52B However, in the illustrated exemplary embodiment, the heat pipe 4169 is connected to the ohmic electrode 4163a and, therefore, may be electrically connected to the common electrode pad 4173d.

[0608] Fig.67A and Fig.67B 4 are a schematic plan view and a cross-sectional view, respectively, of a light emitting device 403 for a display according to another exemplary embodiment.

[0609] Reference Fig.67A and Fig.67B , except that the heat pipe 4269 is insulated from the substrate 421 by the lower insulating layer 461, the light emitting device 403 according to the illustrated exemplary embodiment is different from the reference Fig.52A and Fig.52B The described light emitting device 400 is substantially similar.

[0610] More specifically, the lower insulating layer 461 covers the sidewalls of the through holes h1, h2, h3, h4, and h5, and also covers the sidewall of the hole h6 in which the heat pipe 4269 is formed. The lower insulating layer 461 may also cover the bottom of the hole h6.

[0611] In addition, the heat pipe 4269 may be isolated from the ohmic electrode 463 a. Therefore, the heat pipe 4269 may be electrically insulated from the substrate 421. However, the inventive concept is not limited thereto, and the ohmic electrode 463 a may cover the heat pipe 4269 and be connected to the heat pipe 4269.

[0612] Return to reference FIG. 60A to FIG. 60B , the hole h6 is formed after the lower insulating layer 461 is formed in the light emitting device 400. However, according to the illustrated exemplary embodiment, since the heat pipe 4269 is isolated from the substrate 421 by the lower insulating layer 461 inside the hole h6, the lower insulating layer 461 is also formed inside the hole h6. Therefore, the lower insulating layer 461 is formed after the through holes h1, h2, h3, h4 and h5 and the hole h6 are formed. For example, after the through holes h1, h2, h3, h4 and h5 and the hole h6 are formed, the side walls of the through holes h1, h2, h3, h4 and h5 and the side walls of the hole h6 are then covered with the lower insulating layer 461. Then, when the lower insulating layer 461 is patterned inside the through holes h1, h2, h3, h4 and h5 to form an opening, for example, the lower insulating layer 461 formed on the bottom of the hole h6 may not be patterned by covering the hole h6 with a mask.

[0613] Fig.68A and Fig.68B are schematic plan views and cross-sectional views of a light emitting device 404 for a display according to another exemplary embodiment.

[0614] Reference Fig.68A and Fig.68B , except that the heat pipe 4369 is further disposed below the electrode pads 4173a, 4173b, 4173c and 4173d, the light emitting device 404 according to the illustrated exemplary embodiment is different from the reference Fig.67A and Fig.67B The light emitting device 403 described is substantially similar.

[0615] The heat pipe 4369 may be connected to the electrode pads 4173a, 4173b, 4173c, and 4173d, and thus, heat may be quickly discharged to the outside of the light emitting device 404 through the heat pipe 4369 and the electrode pads 4173a, 4173b, 4173c, and 4173d.

[0616] Each of the light emitting devices 400, 402, 403, and 404 according to the exemplary embodiment includes a first LED stack 423, a second LED stack 433, and a third LED stack 443 that emit red light, green light, and blue light, respectively, and thus can be used as a pixel in a display device. Fig.51 As shown, the display device can be implemented by arranging a plurality of light-emitting devices 400, 402, 403, or 404 on a circuit board 401. Since each of the light-emitting devices 400, 402, 403, and 404 includes a first LED stack 423, a second LED stack 433, and a third LED stack 443, the area of ​​a sub-pixel in one pixel can be increased. In addition, the first LED stack 423, the second LED stack 433, and the third LED stack 443 can be mounted on the circuit board by mounting one light-emitting device, thereby reducing the number of mounting processes.

[0617] like Fig.51 As described, the light emitting device mounted on the circuit board 401 may be driven in a passive matrix driving manner or an active matrix driving manner.

[0618] Fig.69 is a schematic plan view of a display device according to an exemplary embodiment.

[0619] Reference Fig.69 , a display apparatus according to an exemplary embodiment includes a circuit board 501 and a plurality of light emitting devices 500 .

[0620] Circuit board 501 may include circuits for passive matrix driving or active matrix driving. In an exemplary embodiment, circuit board 501 may include interconnects and resistors. In another exemplary embodiment, circuit board 501 may include interconnects, transistors, and capacitors. Circuit board 501 may also have electrode pads disposed on its upper surface to allow electrical connection to the circuits therein.

[0621] The light emitting device 500 is arranged on the circuit board 501. Each light emitting device 500 may constitute a pixel. The light emitting device 500 includes electrode pads 573a, 573b, 573c, 573d electrically connected to the circuit board 501. In addition, the light emitting device 500 may include a substrate 541 located at the upper surface thereof. Because the light emitting devices 500 are isolated from each other, the substrate 541 disposed at the upper surface of the light emitting device 500 is also isolated from each other.

[0622] Will refer to Fig.70A and Fig.70B The details of the light emitting device 500 are described. Fig.70A is a schematic plan view of a light emitting device 500 for a display according to an exemplary embodiment, Fig.70B It is along Fig.70AAlthough the electrode pads 573a, 573b, 573c and 573d are shown and described as being disposed on the upper side of the light emitting device 500, in some exemplary embodiments, the light emitting device 500 may be flip-chip bonded on the upper side of the light emitting device 500. Fig.69 On the circuit board 501 shown in FIG. 1 , therefore, the electrode pads 573a, 573b, 573c and 573d may be disposed on the lower side thereof.

[0623] Reference Fig.70A and Fig.70B The light emitting device 500 may include a first substrate 521, a second substrate 541, a distributed Bragg reflector 522, a first LED stack 523, a second LED stack 533, a third LED stack 543, a first ohmic electrode 525, a second ohmic electrode 535, a third ohmic electrode 545, an ohmic electrode 546, a first color filter 547, a second color filter 557, a first bonding layer 549, a second bonding layer 559, a lower insulating layer 561, an upper insulating layer 571, an ohmic electrode 563a, through-hole vias 563b, 565a, 565b, 567a and 567b, and electrode pads 573a, 573b, 573c, 573d.

[0624] The first substrate 521 may support the LED stacks 523, 533, and 543. The first substrate 521 may be a growth substrate, for example, a GaAs substrate, for growing the first LED stack 523. Specifically, the first substrate 521 may have conductivity.

[0625] The second substrate 541 may support LED stacks 523, 533, and 543. The LED stacks 523, 533, and 543 are disposed between the first substrate 521 and the second substrate 541. The second substrate 541 may be a growth substrate for growing the third LED stack 543. For example, the second substrate 541 may be a sapphire substrate or a GaN substrate, specifically, a patterned sapphire substrate. The first LED stack, the second LED stack, and the third LED stack are disposed on the second substrate 541 in the order of the third LED stack 543, the second LED stack 533, and the first LED stack 523 from the second substrate 541. In an exemplary embodiment, a single third LED stack 543 may be disposed on a single second substrate 541. The second LED stack 533, the first LED stack 523, and the first substrate 521 are disposed on the third LED stack 543. Therefore, the light emitting device 500 may have a single chip structure of a single pixel.

[0626] In another exemplary embodiment, a plurality of third LED stacks 543 may be disposed on a single second substrate 541. The second LED stack 533, the first LED stack 523, and the first substrate 521 may be disposed on each third LED stack 543, and thus the light emitting device 500 has a single chip structure of a plurality of pixels.

[0627] In some exemplary embodiments, the second substrate 541 may be omitted, and the lower surface of the third LED stack 543 may be exposed. In this case, a roughened surface may be formed on the lower surface of the third LED stack 543 by surface texturing.

[0628] Each of the first LED stack 523, the second LED stack 533, and the third LED stack 543 includes a first conductive semiconductor layer 523a, 533a, and 543a, a second conductive semiconductor layer 523b, 533b, and 543b, and an active layer interposed between the first conductive semiconductor layer 523a, 533a, and 543a and the second conductive semiconductor layer 523b, 533b, and 543b. The active layer may have a multi-quantum well structure.

[0629] The LED stack may emit light of a shorter wavelength as it is disposed closer to the second substrate 541. For example, the first LED stack 523 may be an inorganic light emitting diode suitable for emitting red light, the second LED stack 533 may be an inorganic light emitting diode suitable for emitting green light, and the third LED stack 543 may be an inorganic light emitting diode suitable for emitting blue light. The first LED stack 523 may include a well layer based on AlGaInP, the second LED stack 533 may include a well layer based on AlGaInP or AlGaInN, and the third LED stack 543 may include a well layer based on AlGaInN. However, the inventive concept is not limited thereto. When the light emitting device 500 includes a micro-LED having a surface area of ​​less than about 10,000 square microns as known in the art, or less than about 4,000 square microns or 2,500 square microns in other exemplary embodiments, the first LED stack 523 may emit any one of red light, green light, and blue light, and the second LED stack 533 and the third LED stack 543 may emit different ones of red light, green light, and blue light without negatively affecting the operation due to the small form factor of the micro-LED.

[0630] The first conductive semiconductor layer 523a, 533a, and 543a of each of the LED stacks 523, 533, and 543 may be an n-type semiconductor layer, and the second conductive semiconductor layer 523b, 533b, and 543b of each of the LED stacks 523, 533, and 543 may be a p-type semiconductor layer. In the illustrated exemplary embodiment, the upper surface of the first LED stack 523 is an n-type semiconductor layer 523a, the upper surface of the second LED stack 533 is an n-type semiconductor layer 533a, and the upper surface of the third LED stack 543 is a p-type semiconductor layer 543b. More specifically, only the semiconductor layers of the third LED stack 543 are stacked in an order different from that of the first LED stack 523 and the second LED stack 533. The first conductive semiconductor layer 543a of the third LED stack 543 may be subjected to surface texturing to improve light extraction efficiency. In some exemplary embodiments, the first conductive semiconductor layer 533a of the second LED stack 533 may also be subjected to surface texturing.

[0631] The first LED stack 523, the second LED stack 533, and the third LED stack 543 may be stacked to overlap each other and may have substantially the same light emitting area. In addition, in each of the LED stacks 523, 533, and 543, the first conductive semiconductor layer 523a, 533a, and 543a may have substantially the same area as the second conductive semiconductor layer 523b, 533b, and 543b. Specifically, in each of the first LED stack 523 and the second LED stack 533, the first conductive semiconductor layer 523a or 533a may completely overlap the second conductive semiconductor layer 523b and 533b. In the third LED stack 543, a hole h5 is formed on the second conductive semiconductor layer 543b to expose the first conductive semiconductor layer 543a, and therefore, the first conductive semiconductor layer 543a has a slightly larger area than the second conductive semiconductor layer 543b.

[0632] The first LED stack 523 is disposed away from the second substrate 541, the second LED stack 533 is disposed below the first LED stack 523, and the third LED stack 543 is disposed below the second LED stack 533. Since the wavelength of light emitted by the first LED stack 523 may be longer than the wavelengths of light emitted by the second LED stack 533 and the third LED stack 543, light generated from the first LED stack 523 may be emitted to the outside after passing through the second LED stack 533, the third LED stack 543, and the second substrate 541. In addition, since the wavelength of light emitted by the second LED stack 533 may be longer than the wavelength of light emitted by the third LED stack 543, light generated from the second LED stack 533 may be emitted to the outside after passing through the third LED stack 543 and the second substrate 541.

[0633] The distributed Bragg reflector 522 may be disposed between the first substrate 521 and the first LED stack 523. The distributed Bragg reflector 522 reflects light generated from the first LED stack 523 to prevent the light from being lost by absorption by the substrate 521. For example, the distributed Bragg reflector 522 may be formed by alternately stacking AlAs-based semiconductor layers and AlGaAs-based semiconductor layers on each other.

[0634] The first ohmic electrode 525 is disposed between the first LED stack 523 and the second LED stack 533. The first ohmic electrode 525 is in ohmic contact with the second conductive semiconductor layer 523b of the first LED stack 523, and transmits light generated from the first LED stack 523. The first ohmic electrode 525 may be formed as a grid electrode. For example, the first ohmic electrode 525 may include a grid electrode formed of an Au-Zn or Au-Be metal layer. Fig.71B As shown, the first ohmic electrode 525 may include a pad region 525 a , and the through-hole via 563 b may be connected to the pad region 525 a .

[0635] As used herein, the term "grid electrode" may refer to a conductor or conductive structure having a grid shape that can be formed on lines connected to each other and an opening surrounded by the lines. In some exemplary embodiments, the lines connected to each other may be straight lines or curves, but are not limited thereto. In addition, the lines may have the same or different thicknesses as each other, and the openings surrounded by the lines may have the same or different areas as each other. The grid electrode may generally form a regular pattern in a plan view, but in some exemplary embodiments, the pattern formed by the grid electrode may be irregular. The first ohmic electrode 525 may have an opening, and the through-hole passages 565a, 565b, 567a, and 567b pass through the opening without contacting the first ohmic electrode 525.

[0636] The second ohmic electrode 535 is in ohmic contact with the second conductive semiconductor layer 533b of the second LED stack 533. As shown in the figure, the second ohmic electrode 535 contacts the lower surface of the second LED stack 533 between the second LED stack 533 and the third LED stack 543. The second ohmic electrode 535 can be formed as a grid electrode. For example, the second ohmic electrode 535 can include a grid electrode containing Pt or Rh, and can have a multilayer structure such as Ni / Ag / Pt. The second ohmic electrode 535 can include a pad area (see Fig.72A 535a) to connect the through hole passage 565b.

[0637] The third ohmic electrode 545 is in ohmic contact with the second conductive semiconductor layer 543b of the third LED stack 543. The third ohmic electrode 545 may be disposed between the second LED stack 533 and the third LED stack 543, and contact the upper surface of the third LED stack 543. In an exemplary embodiment, the third ohmic electrode 545 may be formed of a metal layer or a conductive oxide layer (such as ZnO) that is transparent to red light and green light. The third ohmic electrode 545 may also be transparent to blue light. In another exemplary embodiment, the third ohmic electrode 545 may be formed as a grid electrode. For example, the third ohmic electrode 545 may include a grid electrode containing Pt or Rh, and may have a multilayer structure of, for example, Ni / Ag / Pt. The third ohmic electrode 545 may include a pad area (see Fig.73A 545a) to connect the through hole passage 567b.

[0638] Each of the first ohmic electrode 525, the second ohmic electrode 535, and the third ohmic electrode 545 is in ohmic contact with the p-type semiconductor layer of each LED stack to facilitate current diffusion. In addition, the grid electrode includes an opening to transmit light generated from the first LED stack 523, the second LED stack 533, and the third LED stack 543.

[0639] The first color filter 547 may be disposed between the third ohmic electrode 545 and the second LED stack 533, and the second color filter 557 may be disposed between the second LED stack 533 and the first LED stack 523. The first color filter 547 transmits light generated from the first LED stack 523 and the second LED stack 533, while reflecting light generated from the third LED stack 543. The second color filter 557 transmits light generated from the first LED stack 523, while reflecting light generated from the second LED stack 533. Therefore, light generated from the first LED stack 523 may be emitted to the outside through the second LED stack 533 and the third LED stack 543, and light generated from the second LED stack 533 may be emitted to the outside through the third LED stack 543. In addition, light loss may be prevented by preventing light generated from the second LED stack 533 from entering the first LED stack 523 or preventing light generated from the third LED stack 543 from entering the second LED stack 533.

[0640] In some exemplary embodiments, the second color filter 557 may reflect light generated from the third LED stack 543 .

[0641] The first color filter 547 and the second color filter 557 can be, for example, a low-pass filter that allows light in a low frequency band (e.g., a long wave band) to pass through it, a band-pass filter that allows light in a predetermined wave band to pass through it, or a band-stop filter that prevents light in a predetermined wave band from passing through it. Specifically, for example, each of the first color filter 547 and the second color filter 557 can be formed by alternately stacking insulating layers (e.g., TiO2 and SiO2) with different refractive indices on top of each other. Specifically, each of the first color filter 547 and the second color filter 557 can include a distributed Bragg reflector (DBR). In addition, the stop band of the distributed Bragg reflector can be controlled by adjusting the thickness of the TiO2 layer and the thickness of the SiO2 layer. Low-pass filters and band-pass filters can also be formed by alternately stacking insulating layers with different refractive indices on top of each other.

[0642] The first bonding layer 549 bonds the second LED stack 533 to the third LED stack 543. The first bonding layer 549 may bond the first color filter 547 to the second ohmic electrode 535 between the first color filter 547 and the second ohmic electrode 535. For example, the first bonding layer 549 may be formed of a transparent organic material or a transparent inorganic material. Examples of organic materials may include SU8, poly(methyl methacrylate) (PMMA), polyimide, polyparaxylene, benzocyclobutene (BCB), etc., and examples of inorganic materials may include Al2O3, SiO2, SiN x Etc. More specifically, the first bonding layer 549 may be formed of spin-on glass (SOG).

[0643] The second bonding layer 559 bonds the second LED stack 533 to the first LED stack 523. As shown, the second bonding layer 559 may be disposed between the second color filter 5...

Claims

1. A light emitting device for a display, the light emitting device comprising: a first LED stack; A second LED stack is disposed below the first LED stack; A third LED stack is disposed below the second LED stack; an electrode pad electrically connected to the first LED stack, the second LED stack, and the third LED stack; an insulating layer, arranged on the first LED stack, and having a plurality of openings distributed on the first LED stack; A first reflective electrode is arranged on the insulating layer, Wherein, the electrode pad comprises: a common electrode pad commonly electrically connected to the first LED stack, the second LED stack, and the third LED stack; and a first electrode pad, a second electrode pad, and a third electrode pad, the first electrode pad being connected to the first LED stack, the second electrode pad being connected to the second LED stack, and the third electrode pad being connected to the third LED stack, Wherein, the first reflective electrode comprises: an ohmic contact layer partially making ohmic contact with the first LED stack through the plurality of openings in the insulating layer; and a reflective layer covering the ohmic contact layer and the insulating layer and having a refractive index lower than that of the first LED stack and the insulating layer, The first LED stack, the second LED stack and the third LED stack are independently driven. The light generated in the first LED stack is emitted to the outside through the second LED stack and the third LED stack, Light generated in the second LED stack is emitted to the outside through the third LED stack.

2. The light emitting device for a display according to claim 1, wherein: The first LED stack emits red light, the second LED stack emits green light, and the third LED stack emits blue light.

3. The light emitting device for a display according to claim 1, wherein: The common electrode pad is connected to the first reflective electrode.

4. The light emitting device for a display according to claim 3, wherein: The light emitting device further comprises: A second transparent electrode is disposed between the second LED stack and the third LED stack and is in ohmic contact with a lower surface of the second LED stack; and a third transparent electrode in ohmic contact with the upper surface of the third LED stack, The common electrode pad is electrically connected to the second transparent electrode and the third transparent electrode.

5. The light emitting device for a display according to claim 4, wherein: The light emitting device further comprises: a 2-1 metal current distribution layer connected to the lower surface of the second transparent electrode; and a third metal current distribution layer connected to the upper surface of the third transparent electrode, The common electrode pad is connected to the 2-1st metal current distribution layer and the third metal current distribution layer.

6. The light emitting device for a display according to claim 5, wherein: The 2-1st metal current distribution layer and the third metal current distribution layer each have a pad region for connecting to the common electrode pad and an extension portion extending from the pad region.

7. The light emitting device for a display according to claim 6, wherein: The common electrode pad is connected to an upper surface of the 2-1st metal current distribution layer and an upper surface of the third metal current distribution layer.

8. The light emitting device for a display according to claim 5, wherein: The light emitting device further comprises: a first color filter disposed between the third transparent electrode and the second LED stack, The third metal current distribution layer is disposed between the first color filter and the second LED stack to be connected to the third transparent electrode through the first color filter.

9. The light emitting device for a display according to claim 6, wherein: The light emitting device further comprises: a second color filter disposed between the second LED stack and the first LED stack; and a 2-2 metal current distribution layer, disposed between the second color filter and the first LED stack, so as to be connected to the second transparent electrode through the second color filter, The second electrode pad is connected to the 2-2 metal current distribution layer.

10. The light emitting device for a display according to claim 9, wherein: The 2-2 metal current distribution layer has a pad region for connecting to the second electrode pad and an extension portion extending from the pad region.

11. The light emitting device for a display according to claim 9, wherein: The first LED stack and the third LED stack include a first conductive semiconductor layer and a second conductive semiconductor layer disposed on a partial region of the first conductive semiconductor layer. The first electrode pad is electrically connected to the first conductive type semiconductor layer of the first LED stack, and the third electrode pad is electrically connected to the first conductive type semiconductor layer of the third LED stack.

12. The light emitting device for a display according to claim 11, wherein: The light emitting device further comprises: A first ohmic electrode is disposed on the first conductive semiconductor layer of the first LED stack; and a third ohmic electrode, disposed on the first conductive semiconductor layer of the third LED stack; The first electrode pad is connected to the first ohmic electrode, The third electrode pad is connected to the third ohmic electrode.

13. The light emitting device for a display according to claim 1, further comprising: The substrate is connected to the lower surface of the third LED stack.

14. The light emitting device for a display according to claim 13, wherein: The substrate is a sapphire substrate or a gallium nitride substrate.

15. The light emitting device for a display according to claim 1, wherein The light emitting device further comprises: an upper insulating layer disposed between the first LED stack, the second LED stack, the third LED stack and the electrode pad, The electrode pad is electrically connected to the first LED stack, the second LED stack, and the third LED stack through the upper insulating layer.

16. The light emitting device for a display according to claim 15, wherein: The upper insulating layer includes at least one material selected from a distributed Bragg reflector, a highly reflective organic material, and a light blocking material.

17. A display device, comprising: Circuit boards; as well as A plurality of light emitting devices are arranged on the circuit board. Each of the plurality of light emitting devices is a light emitting device according to any one of claims 1 to 16, The electrode pads of the light emitting device are electrically connected to the circuit board.

18. The display device according to claim 17, wherein: Each of the plurality of light emitting devices includes a substrate bonded to the third LED stack, The substrates are spaced apart from each other.

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