Micro light emitting diode display and method for manufacturing the same

Abstract

The present invention discloses a micro-LED display configured with a micro-LED or a nano-LED and a transistor and a manufacturing method thereof. The micro-LED display of one embodiment of the present invention comprises: a transistor, which is configured on a substrate and includes a gate, a gate insulating film, an active layer, a source and a drain; a first electrode layer and a second electrode layer, wherein the first electrode layer extends from one of the source and the drain of the transistor, and the second electrode layer is configured on the substrate in a manner of being horizontally separated from the first electrode layer; a first fixed electrode and a second fixed electrode, wherein the first fixed electrode extends from the first electrode layer in an upper direction, and the second fixed electrode extends from the second electrode layer in an upper direction; and a light-emitting diode, the two ends of which are connected to the first fixed electrode and the second fixed electrode.

Description

Technical Field

[0001] The present invention relates to a micro light emitting diode display, and more particularly, to a micro light emitting diode display configured with micro light emitting diodes or nano light emitting diodes and transistors and a method for manufacturing the same. Background Art

[0002] Recently, micro light emitting diodes (LEDs) have attracted much attention as ideal display devices.

[0003] Micro LED displays have self-luminous properties, and when compared to organic light-emitting diodes with the same self-luminous properties, they are superior in terms of response speed, brightness, color reproducibility, and low-power driving properties. Micro LED displays have high durability and life due to the characteristics of inorganic devices, making them more advantageous in terms of application to mobile displays.

[0004] Due to the characteristics of micro light-emitting diodes, they can be assembled into modules, making them suitable for large-scale ultra-high-definition displays.

[0005] Furthermore, the micro light emitting diode display may be embodied as a flexible display.

[0006] Micro LEDs are manufactured by directly implanting (transferring) LEDs at RGB pixel locations.

[0007] In terms of commercialization, micro-LEDs should verify mass transfer feasibility, productivity, process cost, transfer success rate, large-area process, high integration, and compatibility with the backplane. However, the existing transfer process method has fundamental limitations in commercialization.

[0008] In the case of micro-LEDs, for devices with a size of 3 to 100 μm, a large number of them should be implanted into the required position by physical contact. However, the smaller the device size of the micro-LED is, the more difficult it is to implant using physical contact.

[0009] In particular, in the case of the transfer process, it is almost impossible to achieve a micro-LED integration level of ppi (pixel per inch) > 2000.

[0010] Alternatively, without a separate transfer process, a silicon-based micro laser diode (μLEDoS, micro LED on Si) method is considered, which is directly combined with a Si-CMOS backplane chip. In the case of the above-mentioned non-transfer method, a blue micro LED and Si CMOS are combined and a quantum dot-based color conversion layer is used for full-color display. However, due to the introduction of the color conversion layer, the advantages of the micro LED cannot be presented, and not only that, the quantum dot color conversion layer needs to be additionally developed.

[0011] Therefore, it is urgent to develop a new device technology that can overcome the shortcomings of the existing transfer method and achieve high integration. Summary of the invention

[0012] Technical issues

[0013] The object to be achieved by the present invention is to provide a micro light emitting diode display which utilizes fixed electrodes to electrically connect a micro light emitting diode or a nano light emitting diode to a transistor.

[0014] Furthermore, the present invention aims to provide a micro light emitting diode display in which the light emitting diodes are separated from the substrate surface so as to ensure heat dissipation and a wide contact area is ensured by using fixed electrodes.

[0015] The purpose of the present invention is not limited to the above-mentioned purpose. Other purposes and advantages of the present invention that are not mentioned can be understood through the following description and can be more clearly understood through the embodiments of the present invention. In addition, the purposes and advantages of the present invention can be easily achieved through the units and combinations thereof presented in the scope of the invention claims.

[0016] Technical Solution

[0017] The micro light emitting diode display of the embodiment of the present invention includes: a transistor, which is arranged on a substrate, and the transistor includes a gate, a gate insulating film, an active layer, a source and a drain; a first electrode layer and a second electrode layer, the first electrode layer extends from one of the source and the drain of the transistor, and the second electrode layer is arranged on the substrate in a manner of being horizontally separated from the first electrode layer; a first fixed electrode and a second fixed electrode, the first fixed electrode extends from the first electrode layer along an upper direction, and the second fixed electrode extends from the second electrode layer along an upper direction; and a light emitting diode, the two ends of the light emitting diode are combined with the first fixed electrode and the second fixed electrode.

[0018] The transistor may be one of bottom gate-top contact, bottom gate-bottom contact, top gate-top contact, and top gate-bottom contact.

[0019] A gap region may be included between the first electrode layer and the second electrode layer, and the micro light emitting diode display includes a micro light emitting diode arrangement region overlapping a portion of the gap region.

[0020] The first electrode layer and the second electrode layer may be arranged to protrude toward each other.

[0021] The light emitting diodes whose two ends are connected to the first electrode layer and the second electrode layer may be arranged to be separated from the upper surface of the first electrode layer and the upper surface of the second electrode layer.

[0022] The light emitting diode may be in the form of a nanowire having a length of 1 to 100 μm.

[0023] The second electrode layer can be connected to the power supply voltage line V DD Or the base voltage line V ss connect.

[0024] The manufacturing method of the micro-LED display of the embodiment of the present invention may include: step (a), forming a transistor including a gate, a gate insulating film, an active layer, and a metal layer for source and drain on a substrate, and forming a first electrode layer and a second electrode layer, wherein the first electrode layer extends from the metal layer for source and drain of the transistor, and the second electrode layer is formed on the substrate in a manner of being horizontally separated from the first electrode layer via a gap region; step (b), forming an insulating layer, wherein the insulating layer covers the entire gap region between the first electrode layer and the second electrode layer, and forming a micro-LED display having a groove structure in a portion of the insulating layer on the gap region. A light-emitting diode arrangement area; step (c), supplying a fluid including light-emitting diodes onto the substrate, and applying an electrical signal to the first electrode layer and the second electrode layer to arrange the light-emitting diodes in the micro light-emitting diode arrangement area of ​​the groove structure; step (d), removing the lower side portions of the two ends of the light-emitting diodes in the insulating layer; step (e), forming a first fixed electrode extending from the first electrode layer along the upper direction and a second fixed electrode extending from the second electrode layer along the upper direction in the area where the insulating layer has been removed; and step (f), combining the two ends of the light-emitting diode to the first fixed electrode and the second fixed electrode.

[0025] After the step (f), the source and drain metal layers may be etched to form source and drain electrodes.

[0026] The step of forming the above-mentioned insulating layer may include: step (b1), forming the above-mentioned insulating layer on the above-mentioned first electrode layer, the above-mentioned second electrode layer and the above-mentioned gap area; and step (b2), in the above-mentioned insulating layer, partially etching a portion corresponding to the above-mentioned portion of the area on the above-mentioned gap area to form the micro-light-emitting diode arrangement area of ​​the above-mentioned groove structure.

[0027] In the step of arranging the above-mentioned light-emitting diodes in the micro-light-emitting diode arrangement area of ​​the above-mentioned groove structure, an electric signal can be applied to each column in turn in a plurality of columns, a fluid including red micro-light-emitting diodes can be supplied, and an electric signal can be applied to the first electrode layer and the second electrode layer connected to the transistor included in the red pixel to arrange the red light-emitting diodes in the micro-light-emitting diode arrangement area included in the red pixel and dry them, and an electric signal can be applied to each column in turn in a plurality of columns, a fluid including green micro-light-emitting diodes can be supplied, and an electric signal can be applied to the first electrode layer and the second electrode layer connected to the transistor included in the green pixel to arrange the red light-emitting diodes in the micro-light-emitting diode arrangement area included in the green pixel and dry them, and an electric signal can be applied to each column in turn in a plurality of columns, a fluid including blue micro-light-emitting diodes can be supplied, and an electric signal can be applied to the first electrode layer and the second electrode layer connected to the transistor included in the blue pixel to arrange the red light-emitting diodes in the micro-light-emitting diode arrangement area included in the blue pixel and dry them.

[0028] The step of removing the lower portions of the two ends of the light-emitting diode in the above-mentioned insulating layer may include: step (d1), applying photoresist to the above-mentioned insulating layer and the above-mentioned light-emitting diode; step (d2), removing portions of the above-mentioned photoresist corresponding to the above-mentioned two ends of the above-mentioned light-emitting diode to form a photoresist pattern; and step (d3), using the above-mentioned photoresist pattern as an etching mask and removing the lower portions of the above-mentioned two ends of the above-mentioned light-emitting diode in the above-mentioned insulating layer.

[0029] The first fixed electrode and the second fixed electrode may be formed by evaporating or electroplating metal in the region where the insulating layer is removed.

[0030] After the above step (f), the method may further include a step of removing all the above insulating layers.

[0031] Effects of the Invention

[0032] In the micro-LED display of the present invention, as the two ends of the LED are combined with the first electrode layer and the second electrode layer horizontally spaced apart in the micro-LED arrangement area of ​​the groove structure (microhole structure), the transistor can be electrically connected to the LED.

[0033] Furthermore, in the micro light emitting diode display of the present invention, the light emitting diode is separated from the substrate surface, thereby exhibiting a heat dissipation effect, and a wide contact area is ensured by applying a fixed electrode.

[0034] Hereinafter, the above-mentioned effects and specific effects of the present invention will be described together with specific matters for implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A circuit diagram of a general pixel with a 2T-1C structure is shown.

[0036] Figure 2 FIG. 4 is a top view of a light emitting diode display manufactured according to an embodiment of the present invention.

[0037] Figure 3 When cutting along the AB direction Figure 2 A cross-sectional view of a light emitting diode display is shown.

[0038] Figure 4 sectional views for explaining steps of forming a transistor on a substrate according to an embodiment of the present invention.

[0039] Figure 5 2 is a cross-sectional view for explaining an electrode layer forming step of forming a first electrode layer and a second electrode layer according to an embodiment of the present invention.

[0040] Figure 6 FIG. 1 is a cross-sectional view for explaining a step of forming an insulating layer including a micro light emitting diode arrangement region according to an embodiment of the present invention.

[0041] Figure 7 The figure is a top view for explaining a step of forming an insulating layer including a micro light emitting diode arrangement region according to an embodiment of the present invention.

[0042] Figure 8 The figure is a top view for explaining a step of forming an insulating layer including a micro light emitting diode arrangement region according to another embodiment of the present invention.

[0043] Fig. 9 FIG. 1 is a cross-sectional view for explaining a light emitting diode arranging step of arranging light emitting diodes according to an embodiment of the present invention.

[0044] Fig.10FIG. 1 is a cross-sectional view showing a plurality of pixels in which light emitting diodes are arranged according to an embodiment of the present invention.

[0045] Fig.11 FIG. 1 is a top view showing a plurality of pixels of light emitting diodes arranged according to an embodiment of the present invention.

[0046] Fig.12 This is the result of simulating the electric field generated between multiple electrode layers.

[0047] Fig.13 The present invention is a flow chart showing a method of arranging nano-LEDs corresponding to RGB colors.

[0048] Fig.14 2 is a cross-sectional view for explaining a light emitting diode combining step of combining a light emitting diode and an electrode forming step of forming a source electrode and a drain electrode according to an embodiment of the present invention.

[0049] Fig.15 It is a cross-sectional view showing a light emitting diode assembly step, an electrode forming step, an electrode patterning step and a device separation step according to an embodiment of the present invention.

[0050] Description of Reference Numerals

[0051] 100: Light Emitting Diode Display DT: Driving Transistor

[0052] ST:Switching transistor C st : Storage capacitor

[0053] ML: Micro LED 121: Gate

[0054] 123: Gate insulating film 125: Active layer

[0055] 131: first electrode layer 133: second electrode layer

[0056] 140: Insulating layer 151: First fixed electrode

[0057] 153: second fixed electrode 161: source electrode

[0058] 163: Drain 165: Power supply electrode

[0059] 171, 173: Metal layer. DETAILED DESCRIPTION

[0060] The specific structural or functional descriptions of the embodiments based on the concepts of the present invention disclosed in this specification are only used to illustrate the embodiments based on the concepts of the present invention, which can be implemented in various forms based on the concepts of the present invention and are not limited to the embodiments described in this specification.

[0061] The embodiments based on the concept of the present invention may have various changes and various forms, therefore, the embodiments are illustrated in the drawings and described in detail in this specification. However, this does not limit the embodiments based on the concept of the present invention to a specific disclosed form, but includes all changes, equivalent technical solutions or alternative technical solutions within the scope of the idea and technology of the present invention.

[0062] The terms "first" or "second" etc. may be used to describe a variety of structural elements, and the above structural elements are not limited to the above terms. The above terms are only used to distinguish two structural elements. For example, without exceeding the scope of the invention claims based on the concept of the present invention, the first structural element may be named as the second structural element, and similarly, the second structural element may be named as the first structural element.

[0063] When a structural element is "connected" or "coupled" to other structural elements, it can be understood as being directly connected or coupled to other structural elements, or it can be understood as other structural elements being present in between. On the contrary, when a structural element is "directly connected" or "directly coupled" to other structural elements, it can be understood as no other structural elements being present in between. Other expressions that describe the relationship between multiple structural elements, namely, "between" and "directly between" or "adjacent to" or "directly adjacent to" should also be interpreted in the same way.

[0064] The terms used in this specification are only used to illustrate specific embodiments and are not used to limit the present invention. Unless the context clearly indicates, the singular includes the plural. In this specification, the terms "including" or "having" are intended to specify the existence of features, numbers, steps, actions, structural elements, parts or combinations thereof, but do not preclude the existence or additional possibility of more than one feature, number, step, action, structural element or combination thereof.

[0065] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. Terms defined in commonly used dictionaries have the same meaning as those in the context of the relevant technology and cannot be interpreted as ideal or excessive meanings unless clearly defined in this specification.

[0066] Hereinafter, a micro light emitting diode display and a manufacturing method thereof according to various embodiments of the present invention will be described.

[0067] Figure 1 A circuit diagram of a general pixel with a 2T-1C structure is shown. Figure 2 FIG. 4 is a top view of a light emitting diode display manufactured according to an embodiment of the present invention. Figure 3 When cutting along the AB direction Figure 2A cross-sectional view of a light emitting diode display is shown.

[0068] Figure 1 A circuit diagram showing a pixel of the simplest structure manufactured according to the present invention, but the embodiments of the present invention are not limited thereto. Figure 3 For the convenience of explanation, some parts except the substrate 100, the driving transistor DT, and the power supply voltage line V DD And parts other than the micro light emitting diode ML.

[0069] Reference Figures 1 to 3 One pixel of the light emitting diode display 100 may include two transistors ST and DT formed on the substrate 110 and one capacitor C st And micro light emitting diode ML.

[0070] In the present invention, the transistor refers to a driving transistor DT. In the transistor, the first electrode 161 and the second electrode 163 may be a source or a drain, respectively. In the present invention, the first electrode 161 is assumed to be a source, and the second electrode 163 is assumed to be a drain for description.

[0071] The gate of the switching transistor ST is connected to the gate line GL, and the source of the switching transistor ST is connected to the data line DL. The drain of the switching transistor ST is connected to the gate of the driving transistor DT and the storage capacitor C st The first end of the connection.

[0072] The switching transistor ST couples the data line DL and the gate of the driving transistor DT in response to a signal supplied through the gate line GL.

[0073] The gate electrode 121 of the driving transistor DT is connected to the drain electrode 163 of the switch transistor ST through the via hole Via3. The source electrode 161 of the driving transistor DT is connected to the ground GND through the via hole Via1. The drain electrode 163 of the driving transistor DT is connected to the micro light emitting diode ML.

[0074] A gate insulating film 123 is formed on the gate electrode 121 of the driving transistor DT. The gate insulating film 123 is formed to surround the gate electrode 121 .

[0075] The active layer 125 is formed on the gate insulating film 123 . The active layer 125 is formed on a partial region of the gate insulating film 123 .

[0076] The driving transistor DT makes the storage capacitor C st The charging voltage corresponds to the current from the power supply voltage line V DD The current flows through the micro light emitting diode ML to the ground GND.

[0077] Storage capacitor C stConnected between the gate of the driving transistor DT and the ground GND.

[0078] The micro light emitting diode ML is connected to the drain 163 of the driving transistor DT and the power supply voltage line V DD Specifically, the first end of the micro light emitting diode ML is connected to the drain electrode 163 of the driving transistor DT through the first fixed electrode 151. The second end of the micro light emitting diode ML is connected to the power supply voltage line V through the second fixed electrode 153. DD In this case, the supply voltage line V DD The line of the power supply electrode 165 may be formed in a layer different from the driving transistor DT. In the case of being formed in other layers, the power supply electrode 165 is connected to the power supply V DD The second electrode layer 133 and the power supply voltage line V DD Or the base voltage line V ss connect.

[0079] According to an embodiment, the micro light emitting diode ML may be in the form of a nanowire having a length of 1 to 100 μm. In the present invention, the cross-sectional diameter of the nanowire may be about 10 nm to 10 μm. In addition, the nanowire may have a relatively large aspect ratio, which may be about 1.1 to 10. The nanowire with a large aspect ratio has a larger surface area, and therefore, has excellent energy transfer and performance and high transparency.

[0080] like Figures 4 to 13 As shown, the LED display 100 can be manufactured through an insulating layer forming step, an LED arranging step, a fixed electrode forming step and an LED combining step.

[0081] Figure 4 2 is a cross-sectional view for illustrating a step of forming a transistor on a substrate according to an embodiment of the present invention.

[0082] Reference Figure 4 In the basic circuit forming step, a transistor including a basic circuit 120 is formed on a substrate 110. The substrate may be an active drive backplane or an active matrix backplane. The transistor is a transistor that can adjust the current of a micro light emitting diode.

[0083] The transistor includes an active layer 125 , a gate 121 for opening and closing the active layer 125 , a source 161 for directly flowing current, a drain 163 , and a gate insulating film 123 for insulating the gate 121 from the active layer 125 .

[0084] In the drawings of the present invention, the structure of the transistor is a structure in which a gate 121 is formed on a substrate 110. In addition, the present invention shows a structure in which a gate insulating film 123 is formed to surround the gate 121, and an active layer 125 is formed on the gate insulating film 123.

[0085] Based on the position of the gate 121, the transistor is divided into an inverse staggered structure (bottom gate type) and a forward staggered structure (top gate type). In addition, according to the configuration of the gate 121 and the active layer 125, there are four structures: 1) bottom gate-top contact, 2) bottom gate-bottom contact, 3) top gate-top contact, and 4) top gate-bottom contact.

[0086] The top gate structure is a structure in which the gate 121 is disposed on the upper side of the gate insulating film 123 , and the active layer 125 is formed on the lower side of the gate insulating film 123 .

[0087] The bottom gate structure is a structure in which the gate 121 is disposed on the lower side of the gate insulating film 123 , and the active layer 125 is formed on the upper side of the gate insulating film 123 .

[0088] In addition, the bottom contact is a configuration in which the source electrode 161 and the drain electrode 165 are formed prior to the active layer 125 , so that the lower surface of the active layer 125 is in contact with the source electrode 161 and the drain electrode 165 .

[0089] Furthermore, the top contact is a configuration in which the active layer 125 is formed prior to the source electrode 161 and the drain electrode 165 , so that the upper surface of the active layer 125 is in contact with the source electrode 161 and the drain electrode 165 .

[0090] The transistor of the present invention can be applied to one of four structures.

[0091] The gate 121 may include at least one of metals such as aluminum (Al), copper (Cu), tantalum (Ta) or their metal nitrides. The gate insulating film 123 may include at least one of organic, inorganic and / or organic-inorganic substances. The active layer 125 may include at least one of ZnO, indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), amorphous silicon, polycrystalline silicon and crystalline silicon.

[0092] Figure 5 2 is a cross-sectional view for explaining an electrode layer forming step of forming a first electrode layer and a second electrode layer according to an embodiment of the present invention.

[0093] Reference Figure 5 After the foundation forming step, in the electrode layer forming step, the first electrode layer 131 and the second electrode layer 133 are formed.

[0094] like Figure 5 As shown in part (a) of FIG. 1 , a source and drain metal layer 130 surrounding the base circuit 120 is stacked on the base circuit 120 .

[0095] Afterwards, if Figure 5 As shown in part (b) of FIG. 1 , a portion of the source and drain metal layer 130 corresponding to the gap area GA is removed to form the first electrode layer 131 and the second electrode layer 133 .

[0096] Generally, in display circuits, transistors and micro-LEDs should be connected to electrodes, so a lot of metal wiring is required. As a result, parasitic electric fields may be generated in unwanted locations during the assembly of micro-LEDs through electric fields, so this phenomenon should be minimized.

[0097] For this reason, Figure 5 As shown in part (c) of FIG. 1 , an electrode that acts as an electric field shielding layer and an arrangement function is formed in the entire region in a manner that covers all devices of the circuit. If a metal layer 130 for source and drain is formed in the entire region, the formation of a parasitic electric field can be minimized while protecting the underlying devices from the electric field. Figure 5 Part (c) is a plan view of a state after the source and drain metal layer 130 is formed and patterned, and is shown by the first electrode layer 131 and the second electrode layer 133 .

[0098] In the present invention, the source 161 , the drain 163 , the first electrode layer 131 , and the second electrode layer 133 of the transistor can be formed from the source and drain metal layer 130 by etching.

[0099] For example, after the light emitting diode combining step, the source electrode 161 and the drain electrode 163 may be formed by etching the source and drain metal layer 130 .

[0100] According to an embodiment, a photoresist pattern is formed on the first metal layer 130 in a region other than the gap area GA, and the gap area GA portion is removed from the first metal layer 130 by etching using the formed photoresist pattern as an etching mask.

[0101] like Figure 5 Part (b) of Figure 7 As shown, the gap area GA may be in the form of a groove having a short width D1 and a long length.

[0102] Figure 6FIG. 1 is a cross-sectional view for explaining a step of forming an insulating layer including a micro light emitting diode arrangement region according to an embodiment of the present invention. Figure 7 The figure is a top view for explaining a step of forming an insulating layer including a micro light emitting diode arrangement region according to an embodiment of the present invention.

[0103] Reference Figure 6 and Figure 7 After the electrode layer forming step, in the insulating layer forming step, an insulating layer 140 including the micro light emitting diode arrangement area LAA with a groove structure is formed.

[0104] like Figure 6 As shown in part (a) of FIG. 1 , the insulating layer 14 is stacked on the first electrode layer 131 , the second electrode layer 133 , and the gap area GA.

[0105] Afterwards, if Figure 6 As shown in part (b) of the embodiment, a portion of the insulating layer 140 corresponding to the micro-LED arrangement area LAA is partially removed to form a micro-LED arrangement area LAA with a trench structure. The meaning of partial removal is as follows, that is, the insulating material of the portion corresponding to the micro-LED arrangement area LAA is not completely removed, but a predetermined thickness remains.

[0106] For example, the partial etching may be performed by coating a photoresist with different thicknesses on the insulating layer 140 and performing etching so that the insulating material of the portion corresponding to the micro light emitting diode arrangement area LAA is further etched.

[0107] As another example, although not shown, the insulating layer 140 is divided into two or more layers and stacked, and the upper layer of a portion corresponding to the micro LED arrangement area LAA is removed to form the micro LED arrangement area LAA.

[0108] like Figure 7 As shown, the micro LED arrangement area LAA overlaps a portion of the gap area GA. The LED display 100 is formed by a plurality of micro LED arrangement areas LAA at predetermined intervals along the gap direction of the gap area GA.

[0109] The major axis width D2 of the micro LED arrangement area LAA is greater than the width D1 of the gap area GA.

[0110] Figure 8 The figure is a top view for explaining a step of forming an insulating layer including a micro light emitting diode arrangement region according to another embodiment of the present invention.

[0111] Reference Figure 8In the micro light emitting diode arrangement area LAA, the first electrode layer 131 and the second electrode layer 133 may protrude toward each other.

[0112] In other words, the first electrode layer 131 and the second electrode layer 133 may include the protrusions PT in the micro light emitting diode arrangement area LAA, respectively.

[0113] In the case of the protrusion PT, in the subsequent LED arrangement step, the electric field can be concentratedly formed in the micro LED arrangement area LAA, thereby increasing the possibility of successful arrangement of the LEDs ML.

[0114] In this case, preferably, the width D1 corresponding to the electrode gap is adjusted within a range in which the micro-LEDs are smoothly arranged and is smaller than the length of the micro-LEDs.

[0115] As described above, preferably, the micro-LED display of the present invention includes an insulating layer 140 and a micro-LED arrangement area LAA. In the absence of the insulating layer 140, when the micro-LEDs in the form of nanowires are arranged on the electrode layers 131 and 133, a short circuit may occur. Therefore, it is necessary to form the insulating layer 140 directly on the electrode layers 131 and 133, or to form the insulating layer 140 on the entire substrate and then locally form a thin groove structure in the micro-LED arrangement area LAA.

[0116] That is, in the absence of the insulating layer 140 and the micro-LED arrangement area LAA, the micro-LEDs will also be arranged, but since a high current flows at the moment of arrangement, the micro-LEDs will be destroyed.

[0117] When the micro-LED arrangement area LAA is formed, a higher electric field is formed in the micro-LED arrangement area LAA, and electrophoresis will act more selectively on its portion.

[0118] With the insulating layer 140 having the micro-LED arrangement area LAA, the insulating layer 140 will remain on the first electrode layer 131 and the second electrode layer 133. If the thickness of the insulating layer 140 between the micro-LED arrangement area LAA of the groove structure and the electrode layers 131 and 133 is too thick, it tends to reduce the strength of the electric field formed in the electrode gap, so it is preferably of appropriate thickness. For example, the thickness of the insulating layer 140 between the micro-LED arrangement area LAA and the electrode layers 131 and 133 can be about 10nm to 1μm.

[0119] Fig. 9 FIG. 1 is a cross-sectional view for explaining a light emitting diode arranging step of arranging light emitting diodes according to an embodiment of the present invention. Fig.10FIG. 1 is a cross-sectional view showing a plurality of pixels in which light emitting diodes are arranged according to an embodiment of the present invention. Fig.11 FIG. 1 is a top view showing a plurality of pixels of light emitting diodes arranged according to an embodiment of the present invention. Fig.12 This is the result of simulating the electric field generated between multiple electrode layers.

[0120] Reference Figures 9 to 12 After the insulating layer forming step, in the light emitting diode arranging step, the light emitting diodes ML are arranged in the micro light emitting diode arrangement area LAA.

[0121] In the light emitting diode arrangement step, a fluid FL is supplied onto the substrate 110. The fluid FL includes a plurality of micro light emitting diodes ML.

[0122] The fluid FL may be a liquid having a lower dielectric constant than the micro light emitting diode ML when an electrical signal is applied through the electrical signal supplying unit 200 .

[0123] According to an embodiment, the fluid FL may be a liquid including at least one of isopropyl alcohol, acetone, toluene, and water.

[0124] While the fluid FL including the plurality of micro light emitting diodes ML is supplied onto the substrate 110 , the electric signal supplier 200 generates an electric field EF between the first electrode layer 131 and the second electrode layer 133 by supplying an electric signal to the first electrode layer 131 and the second electrode layer 133 .

[0125] When the electric field EF is generated, one of the plurality of micro light emitting diodes ML in the fluid FL may be arranged in the micro light emitting diode arrangement area LAA by the attraction of the electric field EF.

[0126] In this case, the first electrode layer 131 and the second electrode layer 133 may generate the electric field EF and function as an electric field shielding layer for other circuits below the first electrode layer 131 and the second electrode layer 133 .

[0127] The electrical signal supply unit 200 may supply a direct current signal, an alternating current signal, or a pulsed direct current (pulsed DC) signal to the first electrode layer 131 and the second electrode layer 133 .

[0128] The electrical signal supply unit 200 may supply a pulsed DC signal to the first electrode layer 131 and the second electrode layer 133 so as to make the directions of the micro light emitting diodes ML arranged in the micro light emitting diode arrangement area LAA constant.

[0129] The pulse current signal is a periodic electrical signal whose value changes but whose polarity is kept constant. For example, the electrical signal supply unit 200 can generate a pulse DC signal by adding a biased DC signal to an AC signal.

[0130] Figures 10 to 12 1 is a diagram for explaining a method of manufacturing the light emitting diode display 100 when the types of the micro light emitting diodes ML are various.

[0131] When there are three types of micro light emitting diodes ML1, ML2, and ML3, the three types of micro light emitting diodes ML1, ML2, and ML3 can be installed at accurate positions through three steps.

[0132] First, when installing the first micro light emitting diode ML1, the fluid FL including the first micro light emitting diode ML1 is supplied, and the electrical signal supply unit 200 supplies an electrical signal to the first electrode layer 131 and the second electrode layer 133. An attractive force is generated between the first electrode layer 131 and the second electrode layer 133, so that the first micro light emitting diode ML1 can be installed at the corresponding portion.

[0133] In this case, the electric signal supply unit 200 does not apply an electric signal to the third electrode layer 135 and the fourth electrode layer 137 , or may supply an electric signal that does not generate an attractive force in the first electrode layer 131 or the second electrode layer 133 .

[0134] Thereafter, when the second micro light emitting diode ML2 is mounted, the fluid FL including the second micro light emitting diode ML2 is supplied, and the electrical signal supply unit 200 supplies an electrical signal to the second electrode layer 133 and the third electrode layer 135. An attractive force is generated between the second electrode layer 133 and the third electrode layer 135, so that the second micro light emitting diode ML2 can be mounted at the corresponding portion.

[0135] Finally, when the third micro light emitting diode ML3 is installed, the fluid FL including the third micro light emitting diode ML3 is supplied, and the electrical signal supply unit 200 supplies an electrical signal to the third electrode layer 135 and the fourth electrode layer 137. An attractive force is generated between the third electrode layer 135 and the fourth electrode layer 137, so that the third micro light emitting diode ML3 can be installed at the corresponding portion.

[0136] exist Fig.12 Each of the assembly processes shown generates an electric field between a plurality of electrode layers in regions for mounting corresponding micro light emitting diodes, thereby making it possible to perform light emitting diode arrangement.

[0137] Fig.13 The present invention is a flow chart showing a method of arranging nano-LEDs corresponding to RGB colors.

[0138] In a plurality of columns, each column sequentially applies an electrical signal to arrange micro-LEDs having different light-emitting characteristics, for example, nano- or micro-LEDs corresponding to RGB colors as display pixels on a display backplane. In this case, a circuit device that can apply electrical signals individually is used to sequentially form a magnetic field.

[0139] In order to realize RGB full color by using different electric fields for each pixel, the light emitting diodes can be arranged in the following method regardless of the order.

[0140] Among the plurality of light-emitting diodes, a fluid including a red light-emitting diode is supplied, and an electrical signal is applied to the first electrode layer and the second electrode layer connected to the transistor included in the red pixel. The red light-emitting diodes are arranged in the micro light-emitting diode arrangement area included in the red pixel and the substrate (bottom plate) is dried.

[0141] In addition, among the plurality of light-emitting diodes, a fluid including a green light-emitting diode is supplied, and an electrical signal is applied to the first electrode layer and the second electrode layer connected to the transistor included in the green pixel. A red light-emitting diode is arranged in the micro light-emitting diode arrangement area included in the green pixel, and the substrate (bottom plate) is dried.

[0142] In addition, among the plurality of light-emitting diodes, a fluid including a blue light-emitting diode is supplied, and an electrical signal is applied to the first electrode layer and the second electrode layer connected to the transistor included in the blue pixel. Red light-emitting diodes are arranged in the micro light-emitting diode arrangement area included in the blue pixel, and the substrate (bottom plate) is dried.

[0143] As described above, the fluid supply, micro-LED arrangement, and drying processes are repeated to form an RGB nano-LED array on the display, and the electrode formation and metal electrode patterning processes are used to complete the full-color display device.

[0144] Fig.14 The figure is a cross-sectional view for explaining a light emitting diode combining step of combining a light emitting diode and an electrode forming step of forming a source electrode, a drain electrode and a power supply electrode according to an embodiment of the present invention. Fig.15 It is a cross-sectional view showing a light emitting diode assembly step, an electrode forming step, an electrode patterning step and a device separation step according to an embodiment of the present invention.

[0145] Reference Fig.14 and Fig.15 After the light emitting diode arrangement step, in the light emitting diode bonding step, the insulating layer 140 is removed, and two ends of the micro light emitting diode ML are bonded to the first electrode layer 131 and the second electrode layer 133 respectively.

[0146] like Fig.14As shown in part (a) of FIG. 1 , a photoresist PR is applied on the insulating layer 140 where the micro light emitting diodes ML are arranged. In the applied photoresist PR, portions corresponding to the two ends of the micro light emitting diodes ML are removed to form a photoresist pattern. The formed photoresist pattern is etched using an etching mask, thereby removing the lower portions of the two ends of the micro light emitting diodes ML in the insulating layer 140.

[0147] Afterwards, if Fig.14 As shown in part (b) of FIG. 1 , a first fixed electrode 151 and a second fixed electrode 153 are formed by evaporating or electroplating a metal in a region where the insulating layer 140 is removed. As an example of evaporation, electrolytic deposition (electrodeposition, electrophoretic evaporation) can be performed.

[0148] One end of the micro-LED ML can be electrically connected to and physically fixed by the first fixed electrode 151. Similarly, the other end of the micro-LED ML can be electrically connected to and physically fixed by the second electrode layer 133 by the second fixed electrode 153. The heights of the first fixed electrode 151 and the second fixed electrode 153 can be adjusted according to the distance from the electrodes 131 and 133 of the micro-LED arrangement area LAA. Fig.13 As shown, it can have a fixed height or Fig.14 As shown, it can be in the form of a layer such as a thin film.

[0149] like Fig.14 Part (b) of Fig.15 As shown, the insulating layer may remain on the first electrode layer 131 and the second electrode layer 133 .

[0150] Afterwards, if Fig.14 As shown in part (c) of FIG. 1 , the photoresist PR and the insulating layer 140 are entirely removed.

[0151] As described above, after the light emitting diode combining step, the source and drain metal layer 130 may be etched according to a pattern to form the source 161 , the drain 163 , and the power electrode 165 .

[0152] like Fig.14 As shown in part (d), in the first electrode layer 131, a specified area, i.e., the upper area of ​​the active layer 125 is removed, and in the second electrode layer 133, the middle area between the basic circuit 120 and the micro light-emitting diode ML is removed to generate the source 161, the drain 163 and the power electrode 165.

[0153] As the electrodes are etched apart, metal layers 171, 173 will remain on the left side of the source electrode 161 and on the right side of the power electrode 165. In a micro LED display, when a complex circuit such as 2 transistors and 1 capacitor is required, such metal layers 171, 173 can be used as adjacent electrodes.

[0154] Afterwards, although not shown, a material capable of protecting the completed circuit, ie, the source electrode 161 , the drain electrode 163 , the power electrode 165 , the fixed electrodes 151 , 153 and the micro light emitting diode ML may be entirely coated as needed to complete the light emitting diode display 100 .

[0155] As described above, the micro LEDs ML can be easily mounted at the desired position on the substrate using the electric field. In addition, the embodiments described in this specification can be used to rapidly manufacture LED displays at a lower cost and with a higher yield.

[0156] As described above, the micro LED display of the present invention includes a transistor, a first electrode layer 131 , a second electrode layer 133 , a first fixed electrode 151 , a second fixed electrode 153 , and a light emitting diode having two ends connected to the first fixed electrode 151 and the second fixed electrode 153 .

[0157] Specifically, the transistor refers to a driving transistor DT, and as described above, one of transistors having four configuration structures can be selected.

[0158] The first electrode layer 131 extends from one of the source and drain of the transistor. The second electrode layer 133 is disposed on the substrate in a manner of being horizontally spaced apart from the first electrode layer 131. The second electrode layer 133 may be connected to the power supply voltage line V DD Or the base voltage line V ss connect.

[0159] The first fixed electrode 151 extends in an upper direction from the first electrode layer 131. The second fixed electrode 153 extends in an upper direction from the second electrode layer 133. Thus, both ends of the light emitting diode are combined with the first fixed electrode 151 and the second fixed electrode 153.

[0160] The first fixed electrode 151 and the second fixed electrode 153 are disposed apart from each other. The light emitting diode is disposed apart from the upper surface of the first electrode layer 131 and the upper surface of the second electrode layer 133 and is separated from the substrate surface, thereby providing a heat dissipation effect.

[0161] In the manufacturing method, matters regarding the gap region, the micro light emitting diode arrangement region, etc. are the same as described above, and therefore, description thereof will be omitted.

[0162] As described above, the present invention is described with reference to the illustrative drawings, and the present invention is not limited to the embodiments and drawings disclosed in the present invention, and a person skilled in the art of the present invention may make various modifications. At the same time, in the process of describing the above embodiments of the present invention, even if the effects based on the structure are not explicitly described, the effects that can be predicted should be verified by the corresponding structure.

Claims

1. A method for manufacturing a micro light emitting diode display, characterized in that: include: Step (a), forming a transistor including a gate, a gate insulating film, an active layer, and a metal layer for a source and a drain on a substrate, and forming a first electrode layer and a second electrode layer, wherein the first electrode layer extends from the metal layer for the source and the drain of the transistor, and the second electrode layer is formed on the substrate in a manner of being horizontally separated from the first electrode layer via a gap region; Step (b), forming an insulating layer, wherein the insulating layer covers the entire gap region between the first electrode layer and the second electrode layer, and a micro-LED arrangement region with a groove structure is formed in a portion of the insulating layer on the gap region; Step (c), supplying a fluid including light-emitting diodes onto the substrate, and applying electrical signals to the first electrode layer and the second electrode layer to arrange the light-emitting diodes in the micro light-emitting diode arrangement region of the groove structure; Step (d), removing the lower portions of both ends of the light emitting diode in the insulating layer; Step (e), forming a first fixed electrode extending from the first electrode layer in an upward direction and a second fixed electrode extending from the second electrode layer in an upward direction in the region where the insulating layer has been removed; and Step (f), combining two ends of the light emitting diode to the first fixed electrode and the second fixed electrode.

2. The method for manufacturing a micro light emitting diode display according to claim 1, characterized in that: After the step (f), the source and drain metal layers are etched to form source and drain electrodes.

3. The method for manufacturing a micro light emitting diode display according to claim 1, characterized in that: The steps of forming the above-mentioned insulating layer include: Step (b1), forming the insulating layer on the first electrode layer, the second electrode layer and the gap region; and Step (b2), in the insulating layer, partially etching a portion corresponding to the portion of the region on the gap region to form a micro-LED arrangement region of the groove structure.

4. The method for manufacturing a micro light emitting diode display according to claim 1, characterized in that: In the step of arranging the light emitting diodes in the micro light emitting diode arrangement region of the groove structure, In multiple columns, an electrical signal is applied to each column in turn, supplying a fluid including red micro-LEDs, and applying an electrical signal to a first electrode layer and a second electrode layer connected to a transistor included in a red pixel to arrange the red LEDs in a micro-LED arrangement region included in the red pixel and drying the red LEDs, Supplying a fluid including green micro-LEDs, and applying an electrical signal to a first electrode layer and a second electrode layer connected to a transistor included in a green pixel to arrange a red LED in a micro-LED arrangement region included in the green pixel and drying the red LEDs, A fluid including blue micro LEDs is supplied, and an electrical signal is applied to a first electrode layer and a second electrode layer connected to a transistor included in a blue pixel to arrange and dry a red LED in a micro LED arrangement region included in the blue pixel.

5. The method for manufacturing a micro light emitting diode display according to claim 1, characterized in that: The step of removing the lower side portions of both ends of the light emitting diode in the insulating layer comprises: Step (d1), applying photoresist to the insulating layer and the light emitting diode; Step (d2), removing portions of the photoresist corresponding to the two ends of the light emitting diode to form a photoresist pattern; and Step (d3), using the photoresist pattern as an etching mask and removing the lower side portions of the two ends of the light emitting diode in the insulating layer.

6. The method for manufacturing a micro light emitting diode display according to claim 1, characterized in that: The first fixed electrode and the second fixed electrode are formed by evaporating or electroplating metal in the region where the insulating layer is removed.

7. The method for manufacturing a micro light emitting diode display according to claim 1, characterized in that: After the above step (f), the method further includes the step of removing all the above insulating layers.

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