Light emitting device having an LED stack for display and display apparatus having the same

Abstract

To provide a light emitting device for display and a display apparatus including the same.SOLUTION: A light emitting device for a display includes a first LED sub-unit, a second LED sub-unit disposed on the first LED sub-unit, a third LED sub-unit disposed on the second LED sub-unit, electrode pads disposed under the first LED sub-unit, each of the electrode pads being electrically connected to at least one of the first, second, and third LED sub-units, and lead electrodes electrically connected to the electrode pads and extending outward from the first LED sub-unit.SELECTED DRAWING: Figure 2B

Description

[Technical field]

[0001] Exemplary embodiments of the present invention relate to a light emitting device for a display and a display apparatus having the same, and in particular to a micro light emitting device having a stacked structure and a display apparatus having the same. [Background technology]

[0002] Light emitting diodes (LEDs) have been used as inorganic light sources in a variety of technical fields, such as displays, vehicle lamps, general lighting, etc. Due to the advantages of long life, low power consumption and fast response speed, light emitting diodes are rapidly replacing existing light sources.

[0003] Light-emitting diodes have been primarily used as backlight sources in display devices, but micro-LED displays have recently been developed that can directly use light-emitting diodes to realize images.

[0004] Generally, a display device realizes various hues by using a mixture of blue, green and red light hues. The display device includes pixels having sub-pixels corresponding to blue, green and red hues, respectively, and the hue of a particular pixel can be determined based on the hues of the sub-pixels therein, and an image can be displayed by a combination of pixels.

[0005] Because LEDs can emit a variety of hues depending on the material, a display device can have individual LED chips emitting blue, green, and red light arranged on a two-dimensional plane. However, when one LED chip is provided for each subpixel, the number of LED chips to be packaged to form a display device can become very large, e.g., hundreds of thousands or even millions, which can require significant time and complexity in the packaging process.

[0006] In addition, because the subpixels are arranged on a two-dimensional plane in a display device, a relatively large area is required for one pixel including subpixels for blue, green and red light, but reducing the light-emitting area of ​​each subpixel may reduce the brightness of the subpixel.

[0007] Furthermore, micro LEDs are typically around 10,000 μm 2 LEDs have a very small size with a surface area of ​​100 nm, which causes various problems, such as difficulty in probing when measuring the electrical or optical properties of the LEDs.

[0008] The information disclosed in this Background section is merely intended to provide an understanding of the background of the inventive concept and, as such, may include information that does not constitute prior art. Summary of the Invention [Problem to be solved by the invention]

[0009] Light emitting stack structures constructed in accordance with the principles of the present invention and certain exemplary embodiments can increase the light emitting area of ​​each subpixel without increasing the size of the pixel area.

[0010] Light emitting diodes and displays constructed in accordance with the principles of the present invention and some exemplary embodiments, for example light emitting diodes and displays using micro LEDs, have a simplified structure that reduces packaging process time in manufacturing.

[0011] Light emitting diodes and displays using light emitting diodes, e.g., micro-LEDs, constructed in accordance with the principles of the present invention and certain exemplary embodiments have a structure that allows for easy probe testing to measure the electrical and optical properties of the light emitting diode.

[0012] Light emitting diodes and displays constructed in accordance with the principles of the present invention and certain exemplary embodiments, such as light emitting diodes and displays using micro LEDs, have a structure that is stably positioned thereon and easily separable from the temporary substrate, thereby improving manufacturing productivity.

[0013] Additional features of the inventive concepts will be set forth in the description which follows, and in part will be obvious from such description, or may be learned by practicing the inventive concepts. [Means for solving the problem]

[0014] A light emitting device for a display according to an exemplary embodiment includes a first LED subunit, a second LED subunit disposed on the first LED subunit, a third LED subunit disposed on the second LED subunit, and an electrode pad disposed under the first LED subunit, each of the electrode pads including the electrode pad electrically connected to one or more of the first, second and third LED subunits, and a lead electrode electrically connected to the electrode pad and extending outward from the first LED subunit.

[0015] The first LED subunit, the second LED subunit and the third LED subunit are independently drivable, and light generated from the first LED subunit is configured to be emitted outside the light emitting device via the second LED subunit and the third LED subunit, and light generated from the second LED subunit is configured to be emitted outside the light emitting device via the third LED subunit.

[0016] The first, second and third LED subunits may include first, second and third LED stacks configured to emit red, green and blue light, respectively.

[0017] The lead electrode may have a bonding pad disposed on an outer side of the first LED subunit.

[0018] The light emitting device may further include a transparent member covering the first, second and third LED subunits.

[0019] The light emitting device may further include a lower insulating layer interposed between the electrode pad and the lead electrode, the lead electrode being connected to the electrode pad via the lower insulating layer.

[0020] The lower insulating layer may include one or more of a transparent insulating layer, a white insulating layer, and a black insulating layer.

[0021] The light emitting device may further include a transparent member covering the first, second and third LED subunits, and the lower insulating layer is disposed below the transparent member.

[0022] A side surface of the transparent member and a side surface of the lower insulating layer may be substantially flush with each other.

[0023] The electrode pad may include a common electrode pad electrically connected in common to the first, second and third LED subunits, and first, second and third electrode pads electrically connected to the first, second and third LED subunits, respectively, and the lead electrode may include a common lead electrode electrically connected to the common electrode pad, and first, second and third lead electrodes electrically connected to the first, second and third electrode pads, respectively.

[0024] The light emitting device may further include an ohmic electrode in ohmic contact with the first conductive type semiconductor layer of the first LED subunit, and a first reflective electrode interposed between the electrode pad and the first LED subunit and in ohmic contact with the first LED subunit, wherein the first electrode pad is electrically connected to the ohmic electrode, and the common electrode pad is electrically connected to the first reflective electrode at a lower portion of the first reflective electrode.

[0025] The first reflective electrode may include an ohmic contact layer in ohmic contact with the second conductive type semiconductor layer of the first LED subunit, and a reflective layer covering the ohmic contact layer.

[0026] The light emitting device may further include a second transparent electrode interposed between the first LED subunit and the second LED subunit and in ohmic contact with a lower surface of the second LED subunit, a third transparent electrode interposed between the second LED subunit and the third LED subunit and in ohmic contact with a lower surface of the third LED subunit, and a common connector connecting the second transparent electrode and the third transparent electrode to the first reflective electrode, wherein the common connector is electrically connected to the first reflective electrode at an upper portion of the first reflective electrode and to the common electrode pad via the first reflective electrode.

[0027] The common connector may include a first common connector penetrating the first LED subunit, a second common connector electrically connecting the second transparent electrode and the first common connector, and a third common connector electrically connecting the third transparent electrode and the second common connector, and the first common connector and the second common connector may have pad areas for connecting the second common connector and the third common connector, respectively.

[0028] The light emitting device may further include a first color filter interposed between a first LED subunit and the second transparent electrode, and a second color filter interposed between the second LED subunit and the third transparent electrode, wherein the first color filter can transmit light generated by the first LED subunit and can reflect light generated by the second LED subunit, and the second color filter can transmit light generated by the first and second LED subunits and can reflect light generated by the third LED subunit.

[0029] The light emitting device may further include a second connector electrically connecting the second LED subunit and the second electrode pad, and a third connector electrically connecting the third LED subunit and the third electrode pad, wherein the second connector is electrically connected to the first conductive type semiconductor layer of the second LED subunit, and the third connector is electrically connected to the first conductive type semiconductor layer of the third LED subunit.

[0030] One or more of the second connector and the third connector may be in direct contact with the first conductivity type semiconductor layer.

[0031] The second connector may include a second lower connector that penetrates the first LED subunit and a second upper connector that penetrates the second LED subunit, and the third connector may include a third lower connector that penetrates the first LED subunit, a third middle connector that penetrates the second LED subunit, and a third upper connector that penetrates the third LED subunit.

[0032] The light emitting device may further include a connector for electrically connecting the second and third LED subunits to the electrode pads, and the connector and the electrode pads may include different materials from each other.

[0033] A display device according to an exemplary embodiment includes a circuit board and a plurality of light-emitting devices arranged on the circuit board, one or more of the light-emitting devices including a first LED subunit, a second LED subunit arranged on the first LED subunit, a third LED subunit arranged on the second LED subunit, and an electrode pad arranged under the first LED subunit, each of the electrode pads including the electrode pad electrically connected to one or more of the first, second and third LED subunits, and a lead electrode electrically connected to the electrode pad and extending outward from the first LED subunit, and the electrode pads of the light-emitting devices are electrically connected to the circuit board.

[0034] A method for manufacturing a light emitting device for a display according to an exemplary embodiment includes the steps of providing a support substrate, forming a sacrificial layer on the support substrate, forming a membrane on the sacrificial layer, forming a light emitting diode stack having a separation region on the support substrate, the light emitting diode stack including a first LED subunit, a second LED subunit and a third LED subunit, removing the sacrificial layer, and separating the light emitting diode stack and the membrane from the support substrate.

[0035] The method for manufacturing the light-emitting device may further include a step of etching the membrane to form a first opening exposing the sacrificial layer, the first opening being separable by a first portion of the membrane, and the first portion of the membrane may overlap the separation region of the light-emitting diode stack.

[0036] The first portion of the membrane is formed prior to bonding the first LED subunit to the supporting substrate or after forming the isolation regions in the first, second and third LED subunits.

[0037] The light emitting diode stack may further include an electrode pad disposed below the first LED subunit and electrically connected to one of the first, second and third LED subunits.

[0038] The method for manufacturing the light-emitting device may further include the steps of forming a lower insulating layer under the electrode pads of the light-emitting diode stack separated from the supporting substrate, patterning the lower insulating layer to form second openings that expose the electrode pads, and forming lead electrodes connected to each of the electrode pads through the second openings.

[0039] The first opening may substantially surround the light emitting diode stack in plan view.

[0040] The step of forming the membrane may further include forming a central portion overlapping the light emitting diode stack and an outer portion not overlapping the light emitting diode stack, the first portion being disposed between the central portion and the outer portion, and the first portion of the membrane may connect the central portion and the outer portion after the sacrificial layer is removed.

[0041] 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. Effect of the Invention

[0042] Light emitting stack structures constructed in accordance with the principles of the present invention and certain exemplary embodiments can increase the light emitting area of ​​each subpixel without increasing the size of the pixel area.

[0043] Light emitting diodes and displays constructed in accordance with the principles of the present invention and some exemplary embodiments, for example light emitting diodes and displays using micro LEDs, have a simplified structure that reduces packaging process time in manufacturing.

[0044] Light emitting diodes and displays using light emitting diodes, e.g., micro-LEDs, constructed in accordance with the principles of the present invention and certain exemplary embodiments have a structure that allows for easy probe testing to measure the electrical and optical properties of the light emitting diode.

[0045] Light emitting diodes and displays constructed in accordance with the principles of the present invention and certain exemplary embodiments, such as light emitting diodes and displays using micro LEDs, have a structure that is stably positioned thereon and easily separable from the temporary substrate, thereby improving manufacturing productivity. [Brief description of the drawings]

[0046] The accompanying drawings, which are included to provide a further understanding of the invention, and which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with the detailed description, serve to explain the concepts of the invention. [Figure 1] 1 is a schematic plan view of a display device constructed in accordance with an exemplary embodiment of the present invention; [Figure 2A] 1 is a schematic plan view of a light emitting device constructed in accordance with an exemplary embodiment of the present invention; [Figure 2B] FIG. 2B is a cross-sectional view of FIG. 2A. [Figure 3A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 3B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 4A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 4B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 5A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 5B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 6] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 7] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 8A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 8B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 9A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 9B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 9C] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 9D] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 9E] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 10A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 10B]1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 11] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 12A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 12B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 13A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 13B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 14A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 14B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 15A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 15B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 16A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 16B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 17A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 17B]1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 18A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 18B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 19A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 19B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 20A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 20B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 21A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 21B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 22] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 23A] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 23B] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 23C] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 23D]1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 23E] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 23F] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 23G] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 23H] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 23I] 1A and 1B are schematic plan and cross-sectional views illustrating a method for manufacturing a light emitting device for a display according to an exemplary embodiment. [Figure 24A] 1A to 1C are schematic cross-sectional views illustrating a method for manufacturing a temporary support substrate according to an exemplary embodiment. [Figure 24B] 1A to 1C are schematic cross-sectional views illustrating a method for manufacturing a temporary support substrate according to an exemplary embodiment. [Figure 24C] 1A to 1C are schematic cross-sectional views illustrating a method for manufacturing a temporary support substrate according to an exemplary embodiment. [Figure 24D] 1A to 1C are schematic cross-sectional views illustrating a method for manufacturing a temporary support substrate according to an exemplary embodiment. [Figure 25A] 5A to 5C are schematic cross-sectional views illustrating a method for manufacturing a temporary support substrate according to another exemplary embodiment. [Figure 25B] 5A to 5C are schematic cross-sectional views illustrating a method for manufacturing a temporary support substrate according to another exemplary embodiment. [Figure 25C] 5A to 5C are schematic cross-sectional views illustrating a method for manufacturing a temporary support substrate according to another exemplary embodiment. [Figure 25D] 5A to 5C are schematic cross-sectional views illustrating a method for manufacturing a temporary support substrate according to another exemplary embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of various exemplary embodiments or examples of the present invention. As used herein, "embodiment" and "embodiment" are interchangeable words that refer to non-limiting examples of devices or methods that utilize one or more of the inventive concepts disclosed herein. However, it is clear that the various exemplary embodiments can be practiced without utilizing these specific details or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form to avoid unnecessarily obscuring the various exemplary embodiments. Furthermore, the various exemplary embodiments are different from one another but are not necessarily exclusive. For example, specific shapes, configurations and features of the exemplary embodiments may be used or implemented in other exemplary embodiments without departing from the inventive concepts.

[0048] Unless otherwise expressly stated, the illustrated exemplary embodiments should be understood to provide illustrative features of varying detail in some of the ways in which the inventive concepts may be practically implemented, and thus, unless otherwise expressly stated, the features, components, modules, layers, films, panels, regions and / or aspects, etc., of the various embodiments (hereinafter individually or collectively referred to as "elements") may be differently combined, separated, interchanged and / or rearranged without departing from the inventive concepts.

[0049] The use of section hatching and / or shading in the accompanying drawings is generally provided to clarify boundaries between adjacent elements. As such, the presence or absence of section hatching or shading does not imply or indicate any preference or requirement for particular materials, material properties, dimensions, proportions, commonalities between the illustrated elements and / or any other features, attributes, characteristics, etc., unless expressly stated. Also, in the accompanying drawings, the size and relative size of elements may be exaggerated for clarity and / or illustrative purposes. Certain steps may be performed out of the order described, if the illustrative embodiment is differently realizable. For example, two consecutively described steps may be performed substantially simultaneously or in the reverse order from that described. Additionally, identical reference numbers represent identical elements.

[0050] When an element, such as a layer, is referred to as being "on", "connected to" or "coupled to" another element or layer, the element may be directly on, connected to or coupled to the other element or layer, or there may be intervening elements or layers. However, when an element or layer is referred to as being "directly on", "connected to" or "coupled to" another element or layer, there are no intervening elements or layers. For this reason, the term "connected" may refer to a physical, electrical and / or fluid connection, with or without intervening elements. Also, the D1, D2 and D3 axes are not limited to the three axes of a Cartesian coordinate system, such as the x, y and z axes, but may be interpreted in a broader sense. For example, the D1, D2 and D3 axes may be perpendicular to each other, or may indicate different directions that are not perpendicular to each other. For purposes of this disclosure, "one or more of X, Y, and Z" and "one or more selected from the group consisting of X, Y, and Z" may be interpreted as X alone, Y alone, Z alone, or any combination of two or more of X, Y, and Z, such as, for example, 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.

[0051] In this specification, the terms "first", "second", etc. are used to describe various types of elements, but these elements should not be limited by these terms. These terms are used to distinguish one element from another element. Therefore, the first element described below can be named the second element to the extent that it does not deviate from the teachings of the present disclosure.

[0052] Spatially relative terms such as "below," "below," "beneath," "lower," "upper," "upper," "higher" (e.g., as in "sidewall"), "side," and the like may be used herein for descriptive purposes and to describe the relationship of one element to other elements as depicted in the figures. Spatially relative terms are intended to include different orientations of the device during use, operation, and / or manufacture in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, an element described as "below" or "below" another element or feature would be placed "above" the other element or feature. Thus, the exemplary term "below" can include both above and below orientations. Also, the device may be oriented differently (e.g., rotated 90 degrees or at other orientations), and thus, the spatially relative descriptions used herein may be interpreted accordingly.

[0053] The terminology used herein is for the purpose of describing particular embodiments and is not limiting. As used herein, the singular forms are intended to further include the plural forms unless the context clearly dictates otherwise. Additionally, as used herein, the terms "comprises," "comprising," "including," and / or "comprising" refer to the presence of a stated feature, integer, step, operation, element, component, and / or group thereof, but may also refer to the presence or absence of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Additionally, the terms "substantially," "about," and other similar terms are used herein as terms of approximation, not terms of degree, and thus are used to account for inherent deviations in measured, calculated, and / or provided values ​​that are discernible by one of ordinary skill in the art.

[0054] Various exemplary embodiments are described below with reference to cross-sectional and / or exploded illustrations that are schematic illustrations of idealized exemplary embodiments and / or intermediate structures. As such, variations from the shapes of the illustrations are to be expected as a result of, for example, manufacturing techniques and / or tolerances. As such, the exemplary embodiments disclosed herein should not be construed as necessarily limited to the shapes of the specific illustrated regions, but should be construed to include, for example, deviations in shapes that arise due to 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 a device, and thus are not necessarily intended to have a limiting sense.

[0055] Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by a person of ordinary skill in the art to which this disclosure belongs. Terms as defined in commonly used 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 ideal or overly formal sense unless expressly defined herein.

[0056] Exemplary embodiments of the present disclosure will now 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 has a diameter of about 10,000 μm, as is known in the art. 2 In another exemplary embodiment, the micro LED may have a surface area of ​​less than about 4,000 μm, depending on the particular application. 2 Less than or about 2,500 μm 2 In some cases, the surface area may be less than 100 nm.

[0057] FIG. 1 is a schematic plan view of a display device according to an exemplary embodiment.

[0058] Referring to FIG. 1, a display device according to an exemplary embodiment includes a circuit board 101 and a plurality of light emitting devices 200 disposed thereon.

[0059] The circuit board 101 may include circuitry for passive matrix driving or active matrix driving. In one exemplary embodiment, the circuit board 101 may include interconnect lines and resistors. In another exemplary embodiment, the circuit board 101 may include interconnect lines, transistors and resistors. The circuit board 101 may further have electrode pads disposed on its upper surface that allow electrical connection to the circuitry therein.

[0060] The light emitting devices 200 are arranged on the circuit board 101. Each light emitting device 200 can constitute one pixel. The light emitting device 200 has lead electrodes 190a, 190b, 190c, and 190d, a light emitting diode stack 100, and a molding member. The lead electrodes 190a, 190b, 190c, and 190d are electrically connected to the circuit board 101. The light emitting devices 200 are arranged on the circuit board 101 and spaced apart from each other.

[0061] Each of the light emitting devices 200 includes a light emitting diode stack 100. Each of the light emitting diode stacks 100 may have an electrode pad on its lower surface. Each of the lead electrodes 190a, 190b, 190c, and 190d is connected to an electrode pad. .

[0062] FIG. 2A is a schematic plan view of a light emitting device 200 according to an example embodiment, and FIG. 2B is a schematic cross-sectional view taken along a diagonal of FIG. 2A.

[0063] 2A and 2B, a light emitting device 200 according to an example embodiment includes the light emitting diode stack 100, a lower insulating layer 177, lead electrodes 190a, 190b, 190c and 190d, and a transparent molding member 175.

[0064] The light emitting diode stack 100 may include first, second and third LED stacks, and the electrode pads are electrically connected to the first to third LED stacks. FIG. 2B shows two electrode pads 51c and 51d, but electrode pads 51a and 51b are also disposed below the light emitting diode stack 100, as shown in FIG. 5A. The structure of the light emitting diode stack 100 will be described in more detail below.

[0065] The molding member 175 covers the side and top surfaces of the light emitting diode stack 100. The molding member 175 is made of a transparent resin, glass, or the like, and allows light emitted from the light emitting diode stack 100 to pass therethrough.

[0066] The lower insulating layer 177 is disposed under the molding member 175. The lower insulating layer 177 may be formed of a transparent insulating layer, but the concept of the present invention is not limited thereto. For example, the lower insulating layer 177 may include a white insulating layer or a black insulating layer for reflecting or absorbing light. Examples of the transparent insulating layer include SU8, polyimide, phenylene, etc., examples of the white insulating layer include white PSR (photosensitive resist), and examples of the black insulating layer include black epoxy.

[0067] The lower insulating layer 177 is interposed between the lead electrodes 190a, 190b, 190c, and 190d and the light-emitting diode stack 100, and has openings for exposing the electrode pads 51a, 51b, 51c, and 51d.

[0068] The lead electrodes 190a, 190b, 190c, and 190d are connected to the electrode pads 51a, 51b, 51c, and 51d through openings in the lower insulating layer 177. The lead electrodes 190a, 190b, 190c, and 190d extend outward from the lower region of the light-emitting diode stack 100. In particular, each of the lead electrodes 190a, 190b, 190c, and 190d can have a bonding pad outside the lower region of the LED stack 100, and the bonding pads can be bonded to the circuit board 101 of FIG.

[0069] 3A, 3B, 4A, 4B, 5A, 5B, 6, 7, 8A, 8B, 9A, 9B, 9C, 9D, 9E, 10A, 10B, 11 (11(a) to 11(g)), 12A, 12B, 13A, 13B, 14A, 14B, 15A, 15B, 16A, 16B, 17A, 17B, ​​Figures 18A, 18B, Figures 19A, 19B, Figures 20A, 20B, Figures 21A, 21B, Figures 22, 23A, 23B, Figures 23C, 23D, Figures 23E, 23F, Figures 23G, 23H and 23I are schematic plan and cross-sectional views showing a method of manufacturing a light-emitting device for a display according to an illustrative embodiment.

[0070] 3A and 3B, the 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 23 is formed of an AlGaInP-based semiconductor layer and includes a first conductive type semiconductor layer 23a, an active layer, and a second conductive type semiconductor layer 23b. The first conductive type may be n-type, and the second conductive type may be p-type.

[0071] The second conductivity type semiconductor layer 23b is partially removed to expose the first conductivity type semiconductor layer 23a. Although Figures 3A and 3B show one single region of a light emitting device, the substrate 21 may include multiple regions of light emitting devices and the first conductivity type semiconductor layer 23a may be exposed in each region of the light emitting device.

[0072] Then, an ohmic contact layer 26a is formed on the second conductive type semiconductor layer 23b, and a reflective layer 26b is formed covering the ohmic contact layer 26a. The ohmic contact layer 26a and the reflective layer 26b are formed, for example, by a lift-off method. The first reflective electrode 26 is formed by the ohmic contact layer 26a and the reflective layer 26b.

[0073] In another exemplary embodiment, an insulating layer having an opening is formed, an ohmic contact layer 26a is formed in the opening of the insulating layer, and a reflective layer 26b is formed covering the ohmic contact layer 26a and the insulating layer 25.

[0074] The ohmic contact layer 26a is formed of, for example, an Au-Te alloy or an Au-Ge alloy. The reflective layer 26b can include a reflective metal layer, such as Al, Ag, or Au. The reflective layer 26b can also include an adhesive metal layer, such as Ti, Ta, Ni, or Cr, on the upper and lower surfaces of the reflective metal layer to improve the adhesion of the reflective metal layer. In an exemplary embodiment, Au can be used as the reflective layer 26b formed in the first LED stack 23 due to its high reflectivity for red light and low reflectivity for blue and green light. The reflective layer 26b occupies a larger area than the ohmic contact layer 26a and can cover more than 50% of the area of ​​the light emitting device. In some exemplary embodiments, the reflective layer 26b can cover most of the area to improve the light emitting efficiency.

[0075] The first reflective electrode 26 may have a shape in which three corners are removed from a single rectangular area of ​​the light emitting device as shown, and the ohmic contact layer 26a is partially disposed on the remaining one corner, but the concept of the present invention is not limited thereto, and the ohmic contact layer 26a may be distributed widely over the area of ​​the light emitting device.

[0076] Although Figures 3A and 3B show one single region of a light emitting device, multiple regions of light emitting devices are provided on the substrate 21, with a first reflective electrode 26 formed on each region of the light emitting device.

[0077] An ohmic electrode 28 is formed on the exposed first conductivity type semiconductor layer 23a. The ohmic electrode 28 is in ohmic contact with the first conductivity type semiconductor layer 23a and is insulated from the second conductivity type semiconductor layer 23b. Although one single ohmic electrode 28 is shown in Figures 3A and 3B, multiple ohmic electrodes 28 are formed on the substrate 21 in multiple regions of the light emitting device. The ohmic electrode 28 is formed of, for example, an Au-Te alloy, an Au-Ge alloy, or the like.

[0078] 4A and 4B, an insulating layer 29 is formed on the first reflective electrode 26 and the ohmic electrode 28. The insulating layer 29 has openings 29a and 29d for exposing the ohmic electrode 28 and the first reflective electrode 26, respectively, and openings 29b and 29c for exposing the first LED stack 23. The insulating layer 29 is formed of, for example, SiO2, Si3N4, SOG, etc., but the concept of the present invention is not limited thereto, and may include light-transmitting or opaque materials. The openings 29a, 29b, 29c, and 29d are disposed adjacent to the four corners of each region of the light-emitting device.

[0079] The second conductive type semiconductor layer 23b of the first LED stack is exposed through the openings 29b and 29c, but the concept of the present invention is not limited thereto. For example, the second conductive type semiconductor layer 23b may be partially removed in advance, so that the first conductive type semiconductor layer 23a is exposed through the openings 29b and 29c. As another example, a connection pad may be formed on the first LED stack 23, and the connection pad may be exposed through the openings 29b and 29c. The connection pad may be formed at the same time as the ohmic electrode 28 or the first reflective electrode 26 is formed.

[0080] 5A and 5B, electrode pads 51a, 51b, 51c and 51d are formed on the first LED stack 23. The electrode pads 51a, 51b, 51c and 51d are formed on the insulating layer 29. Hereinafter, the electrode pads 51a, 51b and 51c are referred to as the first, second and third electrode pads, respectively, and the electrode pad 51d is referred to as the common electrode pad.

[0081] The first electrode pad 51d is connected to the ohmic electrode 28 through the opening 29a, and the second and third electrode pads 51b and 51c are connected to the first LED stack 23 exposed through the openings 29b and 29c. The common electrode pad 51d is connected to the first reflective electrode 26 through the opening 29d.

[0082] 6, a second LED stack 33 is grown on a second substrate 31, and a second transparent electrode 35 is formed on the second LED stack 33. The second LED stack 33 is formed of a gallium nitride 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 n-type, and the second conductive type may be p-type.

[0083] The second substrate 31 differs from the first substrate 21 in that a gallium nitride based semiconductor layer can be grown on the second substrate 31. The composition of the GaInN well layer of the second LED stack 33 can be determined to emit, for example, green light. The second transparent electrode 35 is in ohmic contact with the second conductivity type semiconductor layer 33b.

[0084] The second transparent electrode 35 is formed of, for example, a metal layer or a conductive oxide film that transmits red light, and in some exemplary embodiments, the second transparent electrode 35 can also transmit green light.

[0085] A first color filter 37 is formed on the second transparent electrode 35. The first color filter 37 transmits light generated by the first LED stack 23 and reflects light generated by the second LED stack 33. The first color filter 37 may be a low-pass filter for passing only a low-frequency region, for example, a long-wavelength region, a band-pass filter for passing only a predetermined wavelength band, or a band-rejection filter for blocking only a predetermined wavelength band. In particular, the first color filter 37 can be formed by alternately stacking insulating layers having different refractive indices. For example, TiO2 and SiO2, Ta2O5 and SiO2, Nb2O5 and SiO2, HfO2 and SiO2, or ZrO2 and SiO2 are alternately stacked. In particular, the first color filter 37 can include a distributed Bragg reflector (DBR). The blocking 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 having different refractive indices.

[0086] 7, a third LED stack 43 is grown on a third substrate 41, and a third transparent electrode 45 and a second color filter 47 are formed on the third LED stack 43. The third LED stack 43 is formed of a gallium nitride semiconductor layer and includes a first conductive type semiconductor layer 43a, an active layer, and a second conductive type semiconductor layer 43b. The active layer may include a GaInN well layer. The first conductive type may be n-type, and the second conductive type may be p-type.

[0087] The third substrate 41 differs from the first substrate 21 in that a gallium nitride based semiconductor layer can be grown on the third substrate 41. The composition of GaInN in the third LED stack 43 can be determined to emit, for example, blue light. The third transparent electrode 45 is in ohmic contact with the second conductivity type semiconductor layer 43b.

[0088] The third transparent electrode 45 is formed of, for example, a metal layer or a conductive oxide film that transmits red and green light. Examples of the conductive oxide film used for the second and third transparent electrodes 35 and 45 include SnO2, InO2, ITO, ZnO, IZO, etc.

[0089] The second color filter 47 transmits the light generated in the first and second LED stacks 23 and 33 and reflects the light generated in the third LED stack 43. The second color filter 47 can be formed by alternately stacking insulating layers having different refractive indices. For example, the second color filter 47 can be formed by alternately stacking TiO2 and SiO2. In particular, the second color filter 47 can include a distributed Bragg reflector. The stop band of the distributed Bragg reflector can be controlled by adjusting the thickness of the TiO2 and SiO2. A low-pass filter and a band-pass filter can also be formed by alternately stacking insulating layers having different refractive indices.

[0090] 8A and 8B, a temporary support substrate 151 is provided for supporting the first to third LED stacks 23, 33, and 43. The temporary support substrate 151 may have an anchor 151a on a surface thereof, and may include a protective layer 153, a sacrificial layer 155, and a membrane 157.

[0091] 9A to 9E are cross-sectional views showing a method for manufacturing a temporary support substrate 151 according to an exemplary embodiment, and FIGS. 10A and 10B are plan views of the temporary support substrate 151 according to an exemplary embodiment.

[0092] 9A, the anchors 151a are formed by etching the surface of a temporary support substrate 151, which may be made of silicon, for example. The anchors 151a may be formed in a substantially mesh-like shape, but the concept of the present invention is not limited thereto, and the anchors 151a may be formed in various shapes.

[0093] 9B, a protective layer 153 is formed on a surface of a temporary supporting substrate 151. The protective layer 153 covers the surface of the temporary supporting substrate 151. The protective layer 153 can prevent the surface of the substrate 151 from being etched when a sacrificial layer 155 formed thereon is etched by an etchant. Thus, the protective layer 153 is formed of a material layer that is resistant to the etchant of the sacrificial layer 155.

[0094] 9C, a sacrificial layer 155 is formed on the protective layer 153 and planarized until the anchors 151a are exposed. Thus, the sacrificial layer 155 is disposed within a limited area surrounded by the anchors 151a. The sacrificial layer 155 is formed of, for example, polysilicon, SiO2, SiNx, polymer, Ti, Ta, etc.

[0095] Referring to FIG. 9D, a membrane 157 is formed covering the anchors 151a and the sacrificial layer 155.

[0096] 9E, an opening 157b exposing the sacrificial layer 155 is formed by patterning the membrane 157. In this case, the shape of the membrane 157 is maintained by the anchors 151a.

[0097] As shown in Figures 10A and 10B, a membrane 157 disposed within the region of the light emitting device is connected to the membrane 157 attached to the anchor 151a by a fuse 157a.

[0098] The fuse 157a can be located in various positions and formed in various shapes. Figure 11 (Figures 11(a)-11(g)) shows fuse 157a having various shapes according to an example embodiment.

[0099] The opening 157b formed in the membrane 157 can function as a passage through which an etching solution can be provided to remove the sacrificial layer 155. In this case, since the membrane 157 is resistant to the etching solution, the membrane 157 can retain its shape during the process of removing the sacrificial layer 155. For example, when the sacrificial layer 155 includes polysilicon, SF6 or XeF2 can be used as the etching solution, and the membrane 157 can be formed of SiO2 or SiNx. As another example, when the sacrificial layer 155 is formed of SiO2, the etching solution can include HF, and the membrane 157 can be formed of Si or SiNx. Also, when the sacrificial layer 155 is formed of SiNx, the etching solution can include H2PO4, and the membrane 157 can be formed of SiO2 or Si. On the other hand, when the sacrificial layer 155 is formed of a polymer, the etching solution can include O2 or F2, and the membrane 157 can be formed of Si, SiO2, or SiNx. Furthermore, if the sacrificial layer 155 is formed of Ti or Ta, the etchant may include SF6, and the membrane 157 may be formed of Si, SiO2, or SiNx.

[0100] In the illustrated exemplary embodiment, the fuse 157a is described as being formed on the temporary support substrate 151, but in some exemplary embodiments, the fuse 157a may be formed after bonding the first to third LED stacks 23, 33 and 43.

[0101] Hereinafter, a method for forming the light-emitting diode stack 100 by bonding the first to third LED stacks 23, 33, and 43 onto the temporary support substrate 151 will be described.

[0102] 12A and 12B, the first LED stack is bonded to the temporary support substrate 151 by bonding the electrode pads 51a, 51b, 51c, and 51d shown in FIG. 5A and FIG. 5B to the temporary support substrate 151. The electrode pads 51a, 51b, 51c, and 51d are bonded to the temporary support substrate 151 through a first bonding layer 53. The first bonding layer 53 is formed of a transparent organic material layer or a transparent inorganic material layer. Examples of the organic material layer include SU8, poly methylmethacrylate (PMMA), polyimide, parylene, benzocyclobutene (BCB), and the like. Examples of the inorganic material layer include Al2O3, SiO2, SiNx, and the like. The organic material layer can be bonded under high vacuum and high pressure. The surface of the inorganic material layer can be planarized by, for example, a chemical mechanical polishing process, and its surface energy can be controlled using plasma, and the bonding can be performed under high vacuum.

[0103] For example, bonding material layers can be disposed on the temporary support substrate 151 and the electrode pads 51 a , 51 b , 51 c and 51 d , respectively, and combined with each other to form the first bonding layer 53 .

[0104] The substrate 21 is then removed from the first LED stack 23. The substrate 21 can be removed from the first LED stack 23, for example, by chemical etching. Thus, the first conductivity type semiconductor layer 23a is exposed. In some exemplary embodiments, the exposed first conductivity type semiconductor layer 23a is subjected to surface texturing to improve light extraction efficiency.

[0105] 13A and 13B, holes L1H2, L1H3, and L1H4 are formed by patterning the first LED stack 23. Holes L1H2 and L1H3 expose electrode pads 51b and 51c, respectively, and hole L1H4 exposes the first reflective electrode 26. Although holes L1H2 and L1H3 are shown exposing electrode pads 51b and 51c, in some exemplary embodiments, holes L1H2 and L1H3 can expose the connection pads when the connection pads are disposed on the electrode pads. Although FIGS. 13A and 13B show that the ohmic contact layer 26a can be exposed through hole L1H4, in some exemplary embodiments, the reflective layer 26b can be exposed by hole L1H4.

[0106] Meanwhile, as shown in Fig. 13A, a portion of the first LED stack 23 disposed on the top of the ohmic electrode 28 is kept intact, so that the ohmic electrode 28 is buried and not exposed. The first LED stack 23 can further be removed in the light emitting device isolation region L1_ISO during patterning the first LED stack 23, so that the insulating layer 29 or the first bonding layer 53 can be exposed. In some example embodiments, the insulating layer 29 and the first bonding layer 53 can be removed in the light emitting device isolation region L1_ISO.

[0107] 14A and 14B, an insulating layer 61 is formed to cover the sidewalls of the holes L1H2, L1H3, and L1H4 and at least partially cover the upper surface of the first conductive type semiconductor layer 23a. The insulating layer 61 is made of SiO2 or the like. The insulating layer 61 exposes the first reflective electrode 26, the second electrode pad 51b, and the third electrode pad 51c in each of the holes.

[0108] Thereafter, connectors 68b, 68c and 68d are formed in each of the holes L1H2, L1H3 and L1H4, respectively. Hereinafter, the connectors 68b, 68c and 68d are also referred to as the second-first connector, the third-first connector and the first common connector, respectively.

[0109] The connectors 68b, 68c, and 68d are electrically connected to the second electrode pad 51b, the third electrode pad 51c, and the common electrode pad 51d, respectively. For example, the 2-1 connector 68b is directly connected to the second electrode pad 51b, the 3-1 connector 68c is directly connected to the third electrode pad 51c, and the common electrode pad 68d is directly connected to the first reflective electrode 26. Each of the connectors 68b, 68c, and 68d can be formed to penetrate the first LED stack 23.

[0110] The connectors 68b, 68c, and 68d may have pad areas on the first LED stack 23. However, the connectors 68b, 68c, and 68d are insulated from the first conductivity type semiconductor layer 23a by the insulating layer 61.

[0111] 15A and 15B, the second LED stack 33 shown in FIG. 6 is bonded onto the first LED stack 23. A bonding material layer is formed on each of the first LED stack 23 and the first color filter 37, and the bonding material layers are bonded to face each other to form a second bonding layer 55. The second bonding layer 55 may further contact the connectors 68b, 68c, and 68d. The second bonding layer 55 may include substantially the same material as the first bonding layer 53.

[0112] The second substrate 31 is then removed from the second LED stack 33 using techniques such as laser lift-off or chemical lift-off, thus exposing the first conductive type semiconductor layer 33a of the second LED stack 33. The exposed first conductive type semiconductor layer 33a is subjected to surface texturing to form a rough surface.

[0113] 16A and 16B, holes L2H2, L2H3, and L2H4 are formed through the second LED stack 33. The holes L2H2, L2H3, and L2H4 may penetrate the second LED stack 33, the second transparent electrode 35, the first color filter 37, and the second bonding layer 55. The connectors 68b, 68c, and 68d are exposed by the holes L2H2, L2H3, and L2H4. The hole L2H4 may also partially expose the top surface of the second transparent electrode 35.

[0114] A portion of the second LED stack 33 may be removed in the light emitting device isolation region L2_ISO such that a top surface of the second bonding layer 55 is exposed in the light emitting device isolation region L2_ISO.

[0115] 17A and 17B, an insulating layer 71 is formed to cover the sidewalls of the holes L2H2, L2H3 and L2H4. The insulating layer 71 may further partially cover the top surface of the second LED stack 33.

[0116] Thereafter, connectors 78b, 78c, and 78d are formed in holes L2H2, L2H3, and L2H4. Hereinafter, connector 78b is also referred to as the 2-2 connector, connector 78c is also referred to as the 3-2 connector, and connector 78d is also referred to as the second common connector. These connectors 78b, 78c, and 78d can be formed to pass through the second LED stack 33.

[0117] The 2-2 connector 78b electrically connects the first conductive type semiconductor layer 33a to the 2-1 connector 68b. As shown, the 2-2 connector 78b is connected to the upper surface of the first conductive type semiconductor layer 33a. To this end, the insulating layer 71 exposes the upper surface of the first conductive type semiconductor layer 33a. The 2-2 connector 78b is also connected to the pad region of the 2-1 connector 68b. The 3-2 connector 78c is connected to the 3-1 connector 68c, in particular, to the pad region of the 3-1 connector 68c. The 3-2 connector 78c is insulated from the second LED stack 33 by the insulating layer 71.

[0118] The second common connector 78d is connected to the first common connector 68d, is connected to the second transparent electrode 35, and is electrically connected to the second conductive type semiconductor layer 33b. The second common connector 78d is connected to the pad region of the first common connector 68d. However, the second common connector 78d is insulated from the first conductive type semiconductor layer 33a by the insulating layer 71.

[0119] The third-2 connector 78c and the second common connector 78d may each have a pad area at a top end.

[0120] 18A and 18B, the third LED stack 43 shown in FIG. 7 is bonded onto the second LED stack 33. A bonding material layer may be formed on the second LED stack 33 with the connectors 78b, 78c and 78d formed thereon, a bonding material layer may be formed on the second color filter 47, and then the two bonding material layers may be combined together to form the third bonding layer 57. The third bonding layer 57 may include substantially the same material as the first bonding layer 53.

[0121] The third substrate 41 is removed from the third LED stack 43 using a technique such as laser lift-off or chemical lift-off, thus exposing the first conductivity type semiconductor layer 43a, and the exposed first conductivity type semiconductor layer 43a is subjected to surface texturing to form a rough surface.

[0122] As shown, the third bonding layer 57 can contact the top surface and sides of the second LED stack 33 .

[0123] 19A and 19B, holes L3H3 and L3H4 penetrating the third LED stack 43 are formed to expose the connectors 78c and 78d. The holes L3H3 and L3H4 may penetrate the third LED stack 43, the third transparent electrode 45, the second color filter 47, and the third bonding layer 57. The connector 78c is exposed by the hole L3H3, and the connector 78d is exposed by the hole L3H4. Also, the top surface of the third transparent electrode 45 is partially exposed by the hole L3H4. Meanwhile, the connector 78b is covered by the third LED stack 43.

[0124] The third LED stack 43, the third transparent electrode 45 and a portion of the second color filter 47 may be removed in the light emitting device isolation areas to expose the third bonding layer 57.

[0125] 20A and 20B, an insulating layer 81 may be formed to cover the sidewalls of the holes L3H3 and L3H4. The insulating layer 81 may further partially cover the top surface of the third LED stack 43.

[0126] Thereafter, connectors 88c and 88d are formed. Hereinafter, connectors 88c and 88d are also referred to as the 3-3 connector and the third common connector, respectively. The 3-3 connector 88c connects the first conductive type semiconductor layer 43a to the 3-2 connector 78c. The 3-3 connector 88c is connected to the upper surface of the first conductive type semiconductor layer 43a and is connected to the pad region of the 3-2 connector 78c.

[0127] The third common connector 88d is connected to the third transparent electrode 45 and simultaneously to the second common connector 78d. Thus, the second conductive type semiconductor layer 43b of the third LED stack 43 is electrically connected to the common electrode pad 51d. The third common connector 88d is insulated from the first conductive type semiconductor layer 43a by the insulating layer 81.

[0128] 21A and 21B, portions of the third bonding layer 57, the second bonding layer 55, the insulating layer 29 and the first bonding layer 53 are sequentially removed in the light-emitting device separation region to expose the membrane 157 on the temporary support substrate 151. The exposed membrane 157 may have openings 157b exposing the sacrificial layer 155, and fuses 157a may be formed to hold the membrane 157 using anchors 151a. If the membrane 157 is not patterned on the temporary support substrate 151, the openings 157b and the fuses 157a may be formed by patterning the membrane 157 after the bonding layers are removed in the light-emitting device separation region.

[0129] Thereafter, the sacrificial layer 155 exposed through the openings 157b of the membrane 157 is removed. In particular, the sacrificial layer 155 may be removed using an etching solution, such that the sacrificial layer 155 is removed in the area surrounded by the anchors 151a, and the membrane 157 is attached to and supported by the anchors 151a.

[0130] As shown in FIG. 22, a plurality of light emitting diode stacks 100 are arranged on a temporary support substrate 151 and are attached and held on a membrane 157 .

[0131] A method for manufacturing a light emitting device 200 using a light emitting diode stack 100 disposed on a temporary support substrate 151 will now be described.

[0132] 23A and 23B, the light emitting diode stacks 100 arranged at regular intervals are separated from the temporary support substrate 151 and transferred to a molding substrate 171 using a picker 161. An adhesive layer 173 is disposed on a surface of the molding substrate 171, and the light emitting diode stacks 100 can be attached to the adhesive layer 173.

[0133] The electrode pads 51a, 51b, 51c and 51d disposed on the lower surface of the light-emitting diode stack 100 are covered with a first bonding layer 53, and the light-emitting diode stack 100 can be attached to a molding substrate 171 with the first bonding layer 53 covered with a membrane 157.

[0134] In this manner, the light emitting diode stacks 100 are formed on the molding substrate 171 at intervals that are relatively larger than the intervals of the light emitting diode stacks 100 disposed on the temporary support substrate 151 .

[0135] 23C, a molding member 175 is formed on the molding substrate 171. The molding member 175 covers and molds the light emitting diode stack 100. The molding member 175 transmits light emitted from the first to third LED stacks 23, 33, and 43.

[0136] 23D and 23E, the carrier substrate 181 is attached onto the molding member 175, and the molding substrate 171 is removed. Thus, the light-emitting diode stack 100 is disposed on the carrier substrate 181 with the electrode pads 51a, 51b, 51c, and 51d disposed thereon. An adhesive layer 183 may be disposed on a surface of the carrier substrate 181, and the molding member 175 may be attached to the adhesive layer 183.

[0137] 23F, the electrode pads 51a, 51b, 51c, and 51d are exposed. The first bonding layer 53 and the molding member 175 disposed on the electrode pads 51a, 51b, 51c, and 51d may be removed by polishing or the like to expose the electrode pads 51a, 51b, 51c, and 51d.

[0138] 23G, a lower insulating layer 177 is then formed. The lower insulating layer 177 is patterned to have openings for exposing the electrode pads 51a, 51b, 51c, and 51d. The lower insulating layer 177 may be formed of a transparent insulating layer, but the concept of the present invention is not limited thereto, and the lower insulating layer 177 may be a white or black insulating layer. Examples of the transparent insulating layer include SU8, polyimide, phenylene, etc., examples of the white insulating layer include white PSR (photosensitive resist), and examples of the black insulating layer include black epoxy.

[0139] 23H, a lead electrode 190 is formed. As shown in Figures 2A and 2B, the lead electrode 190 may include first to third lead electrodes 190a, 190b, and 190c connected to electrode pads 51a, 51b, 51c, and 51d, respectively, and a common lead electrode 190d.

[0140] Thereafter, referring to Fig. 23I, the molding member 175 is diced together with the lower insulating layer 177 to separate into individual light emitting devices. Thus, the light emitting device 200 described with reference to Figs. 2A and 2B is provided. At this stage, a probe test is performed using the lead electrodes 190 to determine whether each light emitting device 200 is defective, and good light emitting devices 200 can be selected.

[0141] Meanwhile, in some exemplary embodiments, a reflective or light-shielding layer is formed covering the sidewalls of the molding member 175 .

[0142] According to an exemplary embodiment, the light emitting device 200 may include first to third LED stacks 23, 33 and 43, with the anodes of each LED stack electrically connected in common and the cathodes of each LED stack independently connected. However, the concept of the present invention is not limited thereto, and the anodes of the first to third LED stacks 23, 33 and 43 may be independently connected to electrode pads, and the cathodes may be electrically connected in common.

[0143] The light emitting device 100 can emit red, green and blue light from the first to third LED stacks 23, 33 and 43, and can therefore be used as one pixel in a display device. The display device according to the exemplary embodiment can include a plurality of light emitting devices 200 on a circuit board 101. Since the light emitting device 200 includes the first to third LED stacks 23, 33 and 43, the area of ​​a subpixel in one pixel can be increased. In addition, since the first to third LED stacks 23, 33 and 43 are implemented by implementing one light emitting device 200, the number of implementation steps can be significantly reduced.

[0144] According to an exemplary embodiment, the light emitting device 200 mounted on the circuit board 101 can be driven by passive matrix methods or active matrix methods.

[0145] According to example embodiments, the light emitting device 200 may be manufactured in various ways different from those described above. Also, the temporary support substrate 151 may be formed differently from that described with reference to Figures 9A to 9E. The temporary support substrate 151 may be formed using a glass substrate or a sapphire substrate.

[0146] 24A to 24D are schematic cross-sectional views showing a method for forming a temporary support substrate 251 using a glass substrate according to an exemplary embodiment.

[0147] 24A, the surface of a substrate 251 is partially etched to form anchors 251a, which are substantially similar to the anchors 151a described with reference to FIG. 9A, and therefore a detailed description thereof will be omitted to avoid redundancy.

[0148] 24B, a sacrificial layer 155 is formed. A sacrificial layer covering the surface of the substrate 251 is deposited and planarized to expose the surfaces of the anchors 251a, so that the sacrificial layer 155 is disposed within a limited area surrounded by the anchors 251a.

[0149] In the illustrated exemplary embodiment, the protective layer 153 may be omitted since the glass substrate has a relatively large etch selectivity compared to the sacrificial layer 155 .

[0150] Thereafter, with reference to Figures 24C and 24D, a membrane 157 is formed covering the sacrificial layer 155 and the anchors 251a, and the membrane 157 may be patterned to form openings 157b and fuses 157a.

[0151] 25A to 25D are schematic cross-sectional views showing a method for forming a temporary support substrate 351 using a substrate having high strength such as a sapphire substrate according to another exemplary embodiment.

[0152] 25A, a sacrificial layer 355 is formed on a substrate 351. Because it is generally difficult to pattern a sapphire substrate to form anchors, in an exemplary embodiment, the step of patterning the sapphire substrate can be omitted.

[0153] 25B, the sacrificial layer 355 is then patterned to expose the surface of the substrate 351. The exposed surface of the substrate 351 can function as an anchor 351a. Thus, the exposed surface can have the shape of the anchor 151a as shown in FIG. 9, and the sacrificial layer 355 is surrounded by the anchor 351a.

[0154] 25C, a membrane 357 is formed on the sacrificial layer 355. The membrane 357 covers the sacrificial layer 355 and the anchors 351a and is attached to the anchors 351a.

[0155] Thereafter, referring to FIG. 25D, membrane 357 is patterned to form openings 357b, and fuses are formed between openings 357b.

[0156] A temporary support substrate 351 can be used in place of the temporary support substrate 151, and the light emitting device 200 can be manufactured by substantially the same process.

[0157] In the light emitting device 200 according to the exemplary embodiment, the first to third LED stacks 23, 33 and 43 can be disposed closer to the electrode pads 51a, 51b, 51c and 51d to emit light of longer wavelengths. 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.

[0158] Since the first LED stack 23 can emit light having a longer wavelength than the second and third LED stacks 33 and 43, the light generated by the first LED stack 23 can be emitted to the outside through the second and third LED stacks 33 and 43 and the substrate 41. Also, since the second LED stack 33 can emit light having a longer wavelength than the third LED stack 43, the light generated by the second LED stack 33 can be emitted to the outside through the third LED stack 43 and the substrate 41. However, the concept of the present invention is not so limited. The light emitting device can be, as known in the art, a luminous flux density (DfD) of about 10,000 μm. 2 or less than about 4,000 μm in other exemplary embodiments. 2 or 2,500 μm 2 When including micro LEDs having a surface area of ​​less than 100 nm, the small form factor of the micro LEDs allows the first LED stack 23 to emit any one of red, green and blue light, and the second and third LED stacks 33 and 43 to emit different ones of red, green and blue light, without adversely affecting operation.

[0159] Meanwhile, the first LED stack 23, the second LED stack 33 and the third LED stack 43 may have the first conductive type semiconductor layers 23a, 33a and 43a that are subjected to surface texturing to improve light extraction efficiency. However, when the second LED stack 33 emits green light, since the green light has higher visibility than the red light or blue light, it may be preferable to increase the luminous efficiency of the first LED stack 23 and the third LED stack 43 rather than the luminous efficiency of the second LED stack 33. Therefore, in order to adjust the brightness of the red light, the green light and the blue light substantially uniformly from each other, surface texturing may be applied to the first LED stack 23 and the third LED stack 43 to improve the light extraction efficiency while the second LED stack 33 is used without surface texturing or with a small degree of surface texturing.

[0160] While certain exemplary examples and embodiments have been described herein, other examples and variations will be apparent from such description, and the inventive concept is therefore not limited to such examples, but rather is to be limited to the broader scope of the appended claims and various obvious modifications and equivalent arrangements as will be apparent to those of ordinary skill in the art.

Claims

1. 1. A display device, comprising: A circuit board including a conductor pattern; a light emitting stack electrically connected to the conductor pattern, A first LED subunit; A second LED subunit disposed on the first LED subunit; A third LED subunit disposed on the second LED subunit; a light-emitting stack comprising: electrode pads disposed on and electrically connected to the first LED subunit, the second LED subunit, and the third LED subunit, each of the electrode pads overlapping at least a portion of the first LED subunit along a vertical direction; a lead electrode electrically connected to the electrode pad, the lead electrode extending from the electrode pad to an outer end of the light emitting stack, and at least a portion of the lead electrode overlapping the first LED subunit in the vertical direction; a molding member covering the light emitting stack; a lower insulating layer that defines an outer boundary of a light emitting device and is disposed between the lead electrode and the molding member and in direct contact with the molding member; A display device in which the outer end of the lead electrode is located inside the outer boundary defined by the lower insulating layer.

2. 10. The display device of claim 1, wherein the first LED subunit, the second LED subunit and the third LED subunit are configured to emit red, green and blue light, respectively, and are independently drivable.

3. The display device according to claim 1 , wherein the lead electrodes are connected to the electrode pads through openings in the lower insulating layer.

4. The display device according to claim 1 , wherein the lead electrodes further comprise a common lead electrode electrically connected to a common electrode pad, the common lead electrode being made of the same material as other lead electrodes.

5. The display device of claim 1 , wherein the molding member is configured to transmit light emitted from the light emitting stack.

6. 10. The display device of claim 1, wherein a plurality of light emitting stacks are disposed on the circuit board, the lower insulating layer being disposed on each of the light emitting stacks respectively to define individual pixels.

7. 10. The display device of claim 1, wherein light generated in the emissive stack is transmitted through a textured surface and extracted externally.

8. 10. The display device of claim 1, wherein the first LED subunit and the second LED subunit include GaInN layers, the composition of the GaInN of the first LED subunit being distinct from the composition of the GaInN of the second LED subunit.

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