WO2012148231A2 - Micro led bundle and method for manufacturing same - Google Patents

Micro led bundle and method for manufacturing same Download PDF

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Publication number
WO2012148231A2
WO2012148231A2 PCT/KR2012/003319 KR2012003319W WO2012148231A2 WO 2012148231 A2 WO2012148231 A2 WO 2012148231A2 KR 2012003319 W KR2012003319 W KR 2012003319W WO 2012148231 A2 WO2012148231 A2 WO 2012148231A2
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WIPO (PCT)
Prior art keywords
layer
semiconductor layer
conductive semiconductor
forming
micro
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PCT/KR2012/003319
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French (fr)
Korean (ko)
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WO2012148231A3 (en
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도영락
성연국
Original Assignee
국민대학교 산학협력단
피에스아이 주식회사
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Publication of WO2012148231A2 publication Critical patent/WO2012148231A2/en
Publication of WO2012148231A3 publication Critical patent/WO2012148231A3/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/20—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0093—Wafer bonding; Removal of the growth substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/16—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
    • H01L33/18—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous within the light emitting region

Definitions

  • the present invention relates to an ultra-small LED device bundle and a method of manufacturing the same, and more particularly to an ultra-small LED device bundle and a method for manufacturing the ultra-small LED device that can minimize the defect rate when attached to the display substrate. It is about.
  • LED TV is LCD as a LCD TV employing a cold cathode fluorescent lamp (cold cathode fluorescent lamp, CCFL) white or tri-color LED devices on behalf of the backlight in the backlight used in conventional LCD TV, precisely with the LED back light TV.
  • CCFL cold cathode fluorescent lamp
  • the current commercially available full-color LED display is the only product that can be encountered in everyday life, the display for outdoor billboards in which tens of thousands to hundreds of thousands of red, green and blue three-color LED lamps are inserted into a very large substrate.
  • a full-featured LED full-color display has not been realized as a home TV or computer monitor.
  • LED device manufacturing method is a metal organic chemical vapor deposition (MOCVD) method on the sapphire substrate of 2 ⁇ 8 inches size p-semiconductor layer, quantum well layer, n-semiconductor layer of III-V material After depositing these, it is a method of manufacturing the LED device of the required form through various post-processing such as cutting / wiring / packaging. If you build your own display for a TV using this method, you can simply calculate the 40-inch TV only by connecting 5 to 40 sheets of 2 to 8 inch wafers.
  • MOCVD metal organic chemical vapor deposition
  • Another approach being pushed by many researchers to realize LED displays is a bottom-up approach based on nanotechnology.
  • This method is a method of realizing a large-area display by growing a nanorod type LED on a single crystal substrate, and then removing a portion and rearranging it in a bottom-up manner on an electrode patterned with pixels.
  • the nanorod LED manufactured by the bottom-up method has poor luminous efficiency compared to the thin film LEDs grown on the wafer, even if the LED display is implemented with this technology, there is a problem of efficiency degradation for a considerable period of time. Can't solve it.
  • nanorod LED device grown in the bottom-up method on the electrode by the bottom-up self-assembly
  • VLS Vapor-Liquid-Solid
  • Another method is a top-down method that cuts high-efficiency LED devices to create an LED display.
  • this method is a method of implementing a display in a one-to-one correspondence method in which micro-LED devices manufactured in a top-down manner are arranged one by one in a sub-pixel position of a large area glass substrate.
  • the individual micro LEDs manufactured by the top-down method are manufactured for each sub-pixel, and thus, were developed for the small micro LED display.
  • the LED device is grown on a sapphire substrate, and then patterned to a micro size to manufacture a micro LED device, and then the electrodes are wired to implement a micro LED display smaller than the wafer substrate size. If this method is used, there is no problem in efficiency, but it is impossible to realize a large-area LED display due to limitations in substrate size and manufacturing process.
  • the ultra-small LED device manufactured by the conventional top-down or bottom-up method is very likely to cause problems of efficiency and stability due to an increase in surface defects caused by etching.
  • the ultra-small LED device manufactured by the conventional top-down or bottom-up method is very likely to cause problems of efficiency and stability due to an increase in surface defects caused by etching.
  • an independent micro LED device due to the surface polarity between the micro devices, mutual cohesion occurs and aggregates are formed, which may result in a large number of defects in the pixel patterning process. Therefore, there is a limitation in implementing mass-efficient high efficiency / large-area LED display devices only by manufacturing independent micromini LED devices.
  • the ultra-small LED device manufactured by the conventional method is placed in a subpixel (pixel position) of the LED display substrate, the micro LED device is too small to stand on the subpixel of the LED display because the size of the LED device is too small. There was a problem of lying down or upside down.
  • the present invention has been made to solve the above-mentioned problems, the first technical problem of the present invention, the surface defects caused by the etching operation of the small LED device can be solved the problem of efficiency and stability and the cohesion between the small LED device due to the increase in surface defects It is to provide a method of manufacturing a small LED device bundle.
  • a second technical problem of the present invention is to provide a micro LED bundle that enables the micro LED device to be accurately positioned without lying on its side or flipped over on a subpixel (pixel position) of the LED display.
  • the present invention to solve the first technical problem
  • the first conductive semiconductor layer may include at least one n-type semiconductor layer
  • the second conductive semiconductor layer may include at least one p-type semiconductor layer
  • the step 2) is;
  • step 2 the step 2);
  • the nanospheres or microspheres may be a polystyrene material.
  • step 3) is performed; 3-1) forming a supporting film on the second electrode layer; 3-2) forming an insulating film on an outer circumferential surface including the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer; 3-3) removing the substrate; 3-4) forming a plurality of bundles by forming a binder on an outer circumferential surface of the plurality of ultra-small LED elements having an insulating film formed thereon; 3-5) forming a first electrode under the first conductive semiconductor layer; 3-6) attaching a coupling linker for self-assembly to the first electrode formed under the first conductive semiconductor layer; And 3-7) manufacturing the plurality of micro LED bundles by removing the support film.
  • the binder is hydrophobic, and one of the plurality of bundles may include 5 to 100 micro LEDs.
  • a first conductive semiconductor layer An active layer formed on the first conductive semiconductor layer;
  • a plurality of micro LED devices having a diameter of a micro or nano size including a second conductive semiconductor layer formed on the active layer, the plurality of micro LED devices is a binder formed on the outer peripheral surface to form a bundle Provides a compact LED device bundle.
  • the binder is hydrophobic, and one bundle may include 5 to 100 micro LEDs.
  • a first electrode layer may be formed below the first conductive semiconductor layer, and a second electrode layer may be formed above the second conductive semiconductor layer.
  • the micro LED device may include an insulating film formed inside the binder.
  • a coupling linker may be included on the surface of at least one electrode layer of the lower surface of the first electrode layer and the upper surface of the second electrode layer.
  • the coupling linker may be complementarily coupled to the substrate of the LED display.
  • the first conductive semiconductor layer may include at least one n-type semiconductor layer
  • the second conductive semiconductor layer may include at least one p-type semiconductor layer
  • the binder may include one or more materials selected from the group consisting of a photosensitive polymer and spin-on-glass.
  • each layer (film), region, pattern or structures is described as being formed on or “under” a substrate, each layer (film), region, or pattern.
  • the terms “on” and “under” include both “directly” and “indirectly”.
  • standard about the top or bottom of each layer is demonstrated based on drawing.
  • the manufacturing method of the ultra-small LED device according to the present invention can solve the problem of cohesion between the ultra-small LED device, the surface defects increase due to the etching operation, thereby reducing efficiency and stability and the ultra-small LED device.
  • the present invention it is not only easy to handle very small LED elements, but also it is possible to accurately position the LED elements on a subpixel (pixel position) of the LED display without lying on its side or upside down. This can dramatically improve the efficiency of the LED display.
  • FIG. 1 is a cross-sectional view showing a step of forming an LED basic device layer according to an embodiment of the present invention.
  • FIG. 2 is a cross-sectional view illustrating a step of forming a second electrode layer, an insulating layer, and a metal mask layer on a second conductive semiconductor layer of the present invention.
  • FIG 3 is a cross-sectional view showing a step of forming a nanosphere or microsphere monolayer film on the metal mask layer of the present invention.
  • FIG. 4 is a cross-sectional view showing the ashing step of the nanospheres or microspheres monolayer film of the present invention.
  • FIG. 5 is a cross-sectional view showing an etching step of the present invention.
  • FIG. 6 is a cross-sectional view showing a step of removing a spear monolayer film, a metal mask layer, and an insulating layer of the present invention.
  • FIG. 7 is a cross-sectional view showing a step of attaching a support film on the second electrode layer of the present invention.
  • FIG. 8 is a view showing a step of coating an insulating film on the outer circumferential surface of each LED device of the present invention.
  • FIG. 9 is a cross-sectional view showing a step of coating the insulating film formed on the outer peripheral surface of the LED device of the present invention with a hydrophobic film.
  • FIG. 10 is a view illustrating a step of manufacturing a micro LED device bundle by commonly connecting a polymer binder to an insulating film formed on outer surfaces of the LED devices of the present invention.
  • FIG. 11 is a cross-sectional view illustrating depositing an electrode under a first conductive semiconductor layer from which a substrate of the present invention is removed.
  • FIG. 12 is a cross-sectional view showing a step of coating a coupling linker for self-assembly on the surface of the electrode of the present invention.
  • FIG. 13 is a cross-sectional view showing a step of manufacturing the independent ultra-small LED device by removing the support film of the present invention.
  • FIG. 14 is a perspective view illustrating an ultra-small LED device bundle manufactured by commonly connecting a binder to the outer circumferential surfaces of the LED devices of the present invention.
  • FIG. 15 is a perspective view illustrating an ultra-small LED device bundle manufactured by forming an insulating film on an outer circumferential surface of each LED device of the present invention and connecting the same with a binder.
  • FIG. 16 is a perspective view of a micro LED device in which a coupling linker for self-assembly is formed on a surface of an electrode of the present invention.
  • FIG. 17 is an ink or paste containing the ultra-small LED device bundle of the present invention.
  • 19 is an electron microscope photograph of a cross section in which an insulating layer and a metal mask layer are formed on a second conductive semiconductor layer of the present invention.
  • FIG. 20A is an electron microscope photograph of a cross section of a nanosphere monolayer film formed on a metal mask layer of the present invention
  • FIG. 20B is an electron microscope photograph of a plane thereof.
  • Fig. 21A is an electron microscope photograph of a cross section obtained by ashing the nanosphere monolayer film of the present invention under an O 2 gas atmosphere
  • Fig. 21B is an electron microscope photograph of the plane thereof.
  • FIG. 22A is an electron microscope photograph of a cross-section of a metal mask layer etched in a Cl 2 gas atmosphere using a nanosphere of which the size of the present invention is reduced
  • FIG. 22B is an electron microscope photograph of the plane thereof.
  • FIG. 23A is an electron microscope photograph of a cross section of a metal mask layer pattern transferred as it is in the shape of polystyrene by an etching process of the present invention
  • FIG. 23B is an electron microscope photograph of a plane thereof.
  • FIG. 24A is an electron microscope photograph of a cross section obtained by etching SiO 2 (insulating layer) under CF 4 and O 2 gas atmospheres using the metal mask layer pattern of the present invention
  • FIG. 24B is an electron microscope photograph of the plane thereof. to be.
  • FIG. 25A is an electron microscope photograph of a section etched by the ICP method under an SiCl 4 and Ar gas atmosphere using the etched insulating layer of the present invention
  • FIG. 25B is an electron microscope photograph of the plane.
  • FIG. 26A is an electron micrograph of a cross-sectional view after removing an insulating layer used as a mask of the present invention
  • FIG. 26B is an electron micrograph of a plane thereof.
  • 27A and 27B show contact angles before (27a) and after (27b) of coating the hydrophobic coating (octadecyltrichlorosilane) on the semiconductor layer coated with the insulating coating (Al 2 O 3 ) of the present invention. ) Is a drawing measured.
  • 28A and 28B are electron micrographs of cross-sections of laser-lift-off processes using a buffer layer or an undoped semiconductor layer and a sapphire substrate to which the supporting film of the present invention is not attached.
  • 29A and 29B are electron micrographs of a cross section obtained by etching the buffer layer or the undoped semiconductor layer to some extent in order to expose the first conductive semiconductor layer of the present invention.
  • 30a and 30b are electron micrographs observed in cross section after further etching by the ICP method of the present invention.
  • FIG. 31A is an electron microscope photograph of a cross section etched to expose a first conductive semiconductor layer by the ICP method of the present invention
  • FIG. 31B is an electron microscope photograph of a plane thereof.
  • FIG. 32 is a photograph observing a cross-section of a micro LED device manufactured by coating a binder of the present invention in a bundle form with an electron microscope.
  • FIG. 33 is a photograph of an electron microscope of a cross section of the electrode Ti deposited on the first conductive semiconductor layer by a sputtering method after the binder of the present invention is slightly removed through an ashing process.
  • 34A and 34B are photographs observed by electron microscopy of a bundle-type micro LED having the support film of the present invention removed with acetone.
  • 35 is a photograph of observing the bundle-type microminiature LED device of the present invention on an electrode substrate with an electron microscope.
  • 36 is a diagram illustrating a spectrum measured after aligning the bundled microminiature LED elements of the present invention to an electrode substrate.
  • 37A to 37C are photographs visually observing a state in which the ultra-small LED bundle of the present invention emits blue light.
  • the ultra-small LED device manufactured according to the prior art is placed on the subpixel (pixel position) of the LED display substrate, the size of the LED device is too small, so the ultra-small LED device on the subpixel of the LED display There was a problem in that it could not be placed right sideways, lying sideways or upside down.
  • step 1) a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer are sequentially formed on a substrate.
  • Figure 1 is a cross-sectional view showing the step of forming the LED elementary device layer according to an embodiment of the present invention, the first conductive semiconductor layer 11, the active layer 12 and the second conductive semiconductor on the substrate 10 Forming a layer (13).
  • the substrate 10 may be a transparent substrate such as sapphire substrate (Al 2 O 3 ) and glass.
  • the substrate 10 may be selected from the group consisting of GaN, SiC, ZnO, Si, GaP and GaAs, conductive substrates.
  • the embodiment will be described as an example of the sapphire substrate.
  • An uneven pattern may be formed on the upper surface of the substrate 10.
  • the nitride semiconductor is grown on the substrate 10, and the growth equipment includes electron beam deposition, physical vapor deposition (PVD), chemical vapor deposition (CVD), and plasma laser deposition (PLD). ), Dual-type thermal evaporator, sputtering, metal organic chemical vapor deposition (MOCVD), etc., but is not limited thereto.
  • a buffer layer and / or an undoped semiconductor layer may be formed on the substrate 10.
  • the buffer layer may be formed of at least one of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN as a layer for reducing a difference in lattice constant from the substrate 10.
  • the undoped semiconductor layer may be implemented as an undoped GaN layer, and functions as a substrate on which a nitride semiconductor is grown.
  • the buffer layer and the undoped semiconductor layer may be formed of only one layer, or both layers may or may not be formed.
  • the thickness of the substrate may be 400 to 1500 ⁇ m, but is not limited thereto.
  • the first conductive semiconductor layer 11 is formed on the substrate 10.
  • the first conductive semiconductor layer 11 may include, for example, an n-type semiconductor layer, and the n-type semiconductor layer may include InxAlyGa1-x-yN (0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ x
  • a semiconductor material having a compositional formula of + y ⁇ 1) for example, InAlGaN, GaN, AlGaN, InGaN, AlN, InN, or the like, may be selected, and the first conductive dopant (eg, Si, Ge, Sn, etc.) may be doped.
  • the thickness of the first conductive semiconductor layer may be 1.5 to 5 ⁇ m, but is not limited thereto.
  • the active layer 12 is formed on the first conductive semiconductor layer 11 and may be formed in a single or multiple quantum well structure.
  • a cladding layer (not shown) doped with a conductive dopant may be formed on and / or under the active layer 12, and the cladding layer doped with the conductive dopant may be implemented as an AlGaN layer or an InAlGaN layer.
  • materials such as AlGaN and AlInGaN may also be used as the active layer 12.
  • the thickness of the active layer may be 0.05 to 0.25 ⁇ m, but is not limited thereto.
  • a second conductive semiconductor layer 13 is formed on the active layer 12, and the second conductive semiconductor layer 13 may be implemented with at least one p-type semiconductor layer, wherein the p-type semiconductor layer is InxAlyGa1-x.
  • the p-type semiconductor layer is InxAlyGa1-x.
  • the second conductive dopant eg, Mg
  • Mg may be doped.
  • the light emitting structure includes the first conductive semiconductor layer 11, the active layer 12, and the second conductive semiconductor layer 13 as minimum components, and different phosphor layers and active layers above and below each layer. , May further include a semiconductor layer and / or an electrode layer. According to a preferred embodiment of the present invention, the thickness of the second conductive semiconductor layer may be 0.08 to 0.25 ⁇ m, but is not limited thereto.
  • step 2) includes the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer to manufacture a plurality of micro LED devices by etching the diameter of the LED device to have a nano or micro size.
  • 2-5) forming a second electrode layer, an insulating layer and a metal mask layer on the second conductive semiconductor layer;
  • 2-6) forming a nanosphere or microsphere monolayer on the metal mask layer and performing self-assembly;
  • 2-7) dry or wet etching the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer at nano or micro intervals according to a pattern;
  • 2-8) removing the insulating layer, the metal mask layer, and the single layer film.
  • the second electrode layer 20 may use a metal or a metal oxide used in a conventional LED device, preferably Cr, Ti, Al, Au, Ni, ITO and oxides or alloys thereof, alone or mixed. It can be used, but is not limited thereto.
  • the thickness of the metal mask layer may be 0.02 ⁇ 0.1 ⁇ m, but is not limited thereto.
  • the insulating layer 21 formed on the second electrode layer 20 may serve as a mask for continuous etching of the second electrode layer, the second conductive semiconductor layer, the active layer, and the first conductive semiconductor layer.
  • Nitride may be used, and as a representative example, silicon oxide (SiO 2 ) or silicon nitride (SiN) may be used, but is not limited thereto.
  • the thickness of the insulating layer may be 0.5 to 1.5 ⁇ m, but is not limited thereto.
  • the metal mask layer 22 formed on the insulating layer 21 serves as a mask layer for etching, and may be a metal commonly used.
  • chromium (Cr) metal may be used. May be, but is not limited thereto.
  • the thickness of the metal mask layer may be 30 ⁇ 150 nm, but is not limited thereto.
  • FIG. 3 is a cross-sectional view showing a step of forming a nanosphere or microsphere monolayer film 30 on the metal mask layer 22 of the present invention.
  • the nanospheres or microspheres monolayer film is formed to serve as a mask for etching the metal mask layer 22, and the method of forming the sphere particles may use the self-assembly of the spheres.
  • the spears are sent on the surface of the water at a constant speed to self-assemble each other.
  • the spear monolayer film can be formed.
  • the diameter of the sphere particles can be selectively used according to the desired diameter of the ultra-small LED device to be produced, preferably polystyrene spheres, silica spheres and the like having a diameter of 50 ⁇ 3000nm, but is not limited thereto.
  • FIG. 4 is a cross-sectional view showing the ashing step of the nanospheres or microspheres monolayer film 30 of the present invention, the spacing of the sphere particles are spaced apart. It can be achieved through an ashing process of a conventional spear monolayer film, and preferably, an ashing process (eg, heating) is performed through oxygen (O 2 ) -based reactive ion ashing and plasma ashing. Can be performed.
  • an ashing process eg, heating
  • oxygen (O 2 ) -based reactive ion ashing and plasma ashing can be performed.
  • FIG. 5 is a cross-sectional view illustrating an etching step of the present invention.
  • FIG. 4 illustrates a process of forming holes by etching between spear particles spaced through an ashing process.
  • the portion in which the sphere particles 30 are formed is not etched, and the spaced part spaced between the sphere particles and the sphere particles is etched to form holes.
  • the hole may be selectively formed from the metal mask layer 22 to the substrate 10.
  • the etching process may use a dry etching method such as reactive ion etching (RIE) or inductively coupled plasma reactive ion etching (ICP-RIE).
  • RIE reactive ion etching
  • ICP-RIE inductively coupled plasma reactive ion etching
  • the dry etching method is capable of unidirectional etching and is suitable for forming such a pattern. That is, the wet etching method is an isotropic etching, the etching is performed in all directions, but the dry etching method can be etched mainly in the depth direction to form a hole, the size and spacing of the holes, etc. It can be formed in a desired pattern.
  • Cl 2 , O 2, or the like may be used as an etching gas capable of etching the metal mask.
  • the spacing (A) of the LED device manufactured by the etching process is matched with the diameter of the sphere particles 30, in this case, the spacing (A) of the LED device may be in the nanometer unit or micrometer unit, more preferably Preferably from 50 to 3000 nm.
  • the removal process may be performed by a conventional wet etching or dry etching method. .
  • the step 2) is; 2-1) sequentially forming a second electrode layer, an insulating layer, and a metal mask layer on the second conductive semiconductor layer; 2-2) forming a polymer layer on the metal mask layer and forming a pattern on the polymer layer at nano or micro intervals; 2-3) dry or wet etching the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer at nano or micro intervals according to a pattern; And 2-4) removing the insulating layer, the metal mask layer, and the polymer layer.
  • a conventional polymer layer that can be used for conventional lithography, etc. is formed on the metal mask layer, and a photo on the polymer layer Achieved by forming patterns at nano or micro intervals through methods such as lithography, e-beam lithography, or nano imprint lithography, followed by dry or wet etching and removal of insulating layers, metal mask layers, and polymer layers Can be.
  • one bundle may be formed by forming a binder on the outer circumferential surface of the plurality of ultra-small LED devices to manufacture the micro-LED bundle according to the present invention.
  • Step 3 3-1) forming a supporting film on the second electrode layer; 3-2) forming an insulating film on an outer circumferential surface including the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer; 3-3) removing the substrate; 3-4) forming a plurality of bundles by forming a binder on an outer circumferential surface of the plurality of micro LED devices having an insulating film formed thereon; 3-5) forming a first electrode under the first conductive semiconductor layer; 3-6) attaching a coupling linker for self-assembly to the first electrode formed under the first conductive semiconductor layer; And 3-7) manufacturing the plurality of micro LED bundles by removing the support film.
  • the support film 70 supports a plurality of ultra-small LED devices so as not to be dispersed when the substrate 10 is removed through a laser lift-off (LLO) method, and also prevents cracking of the LED devices.
  • LLO laser lift-off
  • the material of the support film may be a polymer exposure or bonding metal, the thickness may be 0.3 ⁇ 70 ⁇ m, but is not limited thereto.
  • FIG. 8 illustrates an insulating film 80 formed on an outer circumferential surface including the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer with respect to the micro LED devices having the supporting film of the present invention. This minimizes defects on the surface of tiny LED devices, resulting in improved lifetime and efficiency.
  • the insulating film may be formed not only on the first conductive semiconductor layer 11, the active layer 12, and the second conductive semiconductor layer 13, but also on the outer circumferential surface of the first electrode layer and / or the second electrode layer and other layers.
  • the method of forming an insulating film on the outer circumferential surface of the micro LED devices may be a method of applying or dipping an insulating material on the outer circumferential surfaces of the micro LED devices to which the support film 70 and the substrate 10 are attached, but are not limited thereto. Do not.
  • a material that may be used as the insulating film any one or more selected from the group consisting of SiO 2 , Si 3 N 4 , Al 2 O 3, and TiO 2 may be used, but is not limited thereto.
  • the Al 2 O 3 film can be formed by atomic layer deposition (ALD), and trimethyl aluminum (TMA) and H 2 O sources are supplied in the form of pulses for chemical adsorption and desorption.
  • the thin film can be formed by using.
  • the method of removing the substrate 10 may be a conventionally used method, preferably chemical lift-off (CLO) or laser lift-off (LLO) method. Can be used, but is not limited thereto.
  • CLO chemical lift-off
  • LLO laser lift-off
  • FIG. 10 is a cross-sectional view of manufacturing a micro LED package by forming binders 90 and 91 on the outer circumferential surfaces of the micro LED devices on which the support film of the present invention is formed.
  • one ultra-small LED device bundle is manufactured by treating the outer circumferential surfaces of five micro-LED devices with binders 90 and 91.
  • the number of the ultra-small LED elements forming one bundle may be five or more, preferably 5 to 100 in one bundle for ease of handling.
  • the binder that can be used is not limited as long as it can form a bundle, but preferably a polymer or spin-on-glass may be used, and the polymer may be SU-8, poly (methyl methacrylate) (poly ( methylmethacrylate): PMMA), poly (4-hydroxystyrene) (poly (4-hydroxystyrene), poly (methyl glutarimide) (poly (methyl glutarimide): a photosensitive polymer such as PMGI) may be used, but is not limited thereto
  • the binder may be hydrophobic or coated with a hydrophobic material to prevent aggregation between bundles.
  • the method of forming a plurality of bundles can be used a photolithography method when using a photosensitive polymer.
  • the mask may be positioned according to the photosensitive polymer type, and then ultraviolet rays may be freely left in only a desired portion.
  • Photosensitive polymer types include a positive type and a negative type, and a mask may be positioned according to the type to remove or leave the photosensitive polymer in a desired portion, thereby forming a plurality of LED device bundles.
  • Another method is to use a photosensitive polymer and a dry etching method to mask a portion of the photosensitive polymer to be left with a mask and ashing to remove a plurality of bundles in the desired position.
  • spin-on-glass is used instead of the photosensitive polymer to coat the first conductive semiconductor layer from which the substrate is removed, and then a plurality of LED device bundles are formed at desired positions by etching. You may.
  • the bundle forming method is exemplary, and in addition to this, a bundle of micro LED devices may be formed through various methods.
  • the first electrode 110 may be used without limitation as long as it is a material generally used in an LED device.
  • the material is a single or mixed material such as Cr, Ti, Al, Au, Ni, ITO and oxides or alloys thereof. This can be used.
  • the thickness of the electrode may be 0.02 ⁇ 1 ⁇ m, but is not limited thereto.
  • FIG. 12 is a cross-sectional view illustrating a step of coating a coupling linker 120 for self-assembly on the surface of the first electrode 110 of the present invention.
  • the coupling linker 120 for self-assembly may be coated on the surface of the first electrode 110, and the coupling linker 12O may be coupled to a subpixel (pixel position) of the corresponding LED display substrate.
  • a second linker (not shown) is formed, even when the micro LED element is transferred or added to the sub pixel in the form of ink or paste, the micro LED element does not lie down or flipped, and the electrode surface is positioned on the sub pixel at a desired position. It can be attached.
  • the second linker is not formed, if the functional group remaining in the coupling linker is bonded to the surface of the subpixel of the LED display substrate, the small LED device may not solve the problem of laying down or flipping.
  • the coupling linker must be coupled to the electrode surface of the micro LED device and the surface of the subpixel of the display substrate and / or the second linker formed on the subpixel, and thus may have two or more functional groups.
  • a thiol-based aminoethanethiol and an oxide reacting with a metal and an aminopropyltrirthoxysilane reacting with the metal may be used, but are not limited thereto.
  • the second linker formed on the surface of the subpixel of the display substrate may be used without limitation as long as it can be complementarily bonded to the coupling linker of the present invention.
  • the same series as the coupling linker may be used.
  • FIG. 13 is to manufacture the independent micro LEDs 130 and 131 by removing the support film 70.
  • the coupling linker 120 may be formed on at least one surface of the second electrode 20 and the first electrode 110 after removing the support film 70.
  • the present invention the first conductive semiconductor layer; An active layer formed on the first conductive semiconductor layer; A plurality of micro LED devices having a diameter of a micro or nano size including a second conductive semiconductor layer formed on the active layer, the plurality of micro LED devices is a binder formed on the outer peripheral surface to form a bundle Provides a compact LED device bundle.
  • FIG. 14 is a perspective view illustrating a micro LED device according to the present invention.
  • the micro LED device according to the present invention includes an active layer 141 formed on the first conductive semiconductor layer 140 and a second conductive semiconductor layer formed on the active layer 141. 142, wherein a first electrode 143 is formed under the first conductive semiconductor layer 140, and a second electrode 144 is formed on the second conductive semiconductor layer 142.
  • a separate buffer layer, an active layer, a phosphor layer, and / or a semiconductor layer may be further included.
  • the insulating film 150 to surround the active layer 141 formed on the first conductive semiconductor layer 140, including the outer peripheral surface of part or all of the second conductive semiconductor layer 142 formed on the active layer 141 Can be formed.
  • the first and second electrodes 143 and / or the second electrode 144 may be formed to include an outer circumferential surface thereof.
  • the drawings of the present invention show that the insulating film and / or the binder cover only a portion of the semiconductor layer, but actually cover the entire outer circumferential surface thereof. Can be.
  • FIG. 15 is a perspective view illustrating the ultra-small LED device bundle of the present invention, wherein the individual micro-LED devices bundle a binder 90 around the outer circumferential surface thereof to form a bundle.
  • the number of micro LEDs forming one bundle may be five or more.
  • FIG. 15 illustrates only a part of the binder 90 in order to show the structure of the ultra-small LED device.
  • the polymer binder 80 may form a bundle around the outer circumferential surface of the ultra-small LED devices.
  • FIG. 15 illustrates a configuration in which the insulating film 80 is formed inside the binder 90, the present invention is not limited thereto, and the binder 90 may be formed without forming the insulating film 80.
  • FIG. 16 is a perspective view of a micro LED device in which a coupling linker for self-assembly is formed on a surface of an electrode of the present invention.
  • FIG. 16 As described above, since the micro LED device is too small in size, when the micro LED device is attached to a subpixel (pixel position) of the LED display substrate, there may be a problem that the micro LED device does not stand upright and is lying or flipped over. In order to prevent this, a coupling linker 170 for self-assembly may be formed on at least one surface of the first electrode 143 and the second electrode 144.
  • a second linker (170) is formed on the surface of the first electrode (143) and can be coupled to the coupling linker (17O) in a subpixel (pixel position) of the LED display substrate corresponding thereto.
  • the electrode surface may be attached to the sub-pixel at the desired position without lying or upside down even when the micro-LED element is transferred or added to the sub-pixel in the form of ink or paste. .
  • the coupling linker 170 is formed on both the first electrode 143 and the second electrode 144, a part of the ultra-small LED device coupled to the subpixel (pixel position) of the LED display substrate may be the first electrode ( 143 is coupled and the second electrode 144 is coupled. In this case, when an alternating current is applied to the LED display substrate, the LED display can be driven.
  • the shape of the ultra-small LED device of the present invention may be formed without limitation, such as cylindrical, rectangular parallelepiped, preferably cylindrical, in the case of a cylindrical diameter (circle diameter) may be 50 ⁇ 3000nm, height (second Length from one electrode to the second electrode) may be 1.5 ⁇ 7 ⁇ m, but is not limited thereto.
  • the micro LED bundle of the present invention can be transferred directly to a subpixel of the display substrate or in the form of an ink or paste.
  • Buffered or undoped semiconductor layer (undoped GaN, 2.4-2.8 ⁇ m thick), first conductive semiconductor layer (n ⁇ ) on a sapphire substrate (2 inch wafer size, 430 ⁇ 25 ⁇ m) to manufacture an LED basic device layer (GaN) Type GaN, 2.0-2.4 ⁇ m thick), active layer (InGaN / GaN multi-quantum well, 100-140 ⁇ m), and second conductive semiconductor layer (p-type GaN, 200 nm thick) were formed using MOCVD method (FIG. 18). Reference).
  • the LED basic device layer manufactured as described above was manufactured as a micro LED device by the following method.
  • SiO 2 800 nm to 1 ⁇ m thick
  • a chromium layer 100 to 120 nm thick
  • PECVD thermal evaporation, respectively
  • thermal deposition 130 ⁇ 140A, 9.0x10 -6 torr , 20 ⁇ 30 minutes) (see FIG. 19).
  • polystyrene nanospheres were prepared as monolayer films (960-1000 nm thick) well aligned in hexagonal form and formed on the metal mask layer (see FIGS. 20A and 20B).
  • the monolayer film was reduced to a size of 500-800 nm through an ashing process (50W, 0.05torr, O 2 100sccm) in an O 2 gas atmosphere (see FIGS. 21A and 21B).
  • the metal mask layer was etched under Cl 2 gas atmosphere by RIE method (dry etching method) (50W, 0.08torr, Cl 2 40sccm) (see FIGS. 22A and 22B).
  • the semiconductor layer (GaN) was etched by ICP method under SiCl 4 and Ar gas atmosphere using the insulating layer etched by the rod pattern (RF 50W, ICP 300W, 3 torr, SiCl 4 2sccm, Ar 20sccm)
  • the pattern was prepared (see FIGS. 25A and 25B).
  • the insulating layer which was used as a mask to manufacture the semiconductor layer rod pattern, was removed by etching under a CF 4 and O 2 gas atmosphere (see FIGS. 26A and 26B).
  • Atomic layer deposition (ALD) method trimethylaluminum (TMA) as metal reactant, water vapor as oxygen source, TMA vapor pressure of 0.04 torr
  • TMA trimethylaluminum
  • Ar was used as the carrier gas and the purging gas
  • an insulating film Al 2 O 3
  • OTS octadecyltrichlorosilane
  • a supporting film was attached on the second electrode layer by using an epoxy resin (cyanoacrylate adhesive metal-type, purchased from Sigma Aldrich) (thickness: 3.5-5 ⁇ m). Subsequently, the sapphire substrate was removed by performing a lift-off process using a laser toward the buffer layer or the undoped semiconductor layer and the sapphire substrate to which the support film was not attached (see FIGS. 28A and 28B).
  • an epoxy resin cyanoacrylate adhesive metal-type, purchased from Sigma Aldrich
  • the buffer layer or the undoped semiconductor layer was removed by etching by the ICP method under SiCl 4 and Ar gas atmosphere (RF 50W, ICP 300W, 3 torr, SiCl 4 2sccm, Ar 20sccm), Through this process, it was possible to obtain an independent ultra-small LED rod form to which the support film was attached (see FIGS. 29A and 29B, FIGS. 30A and 30B, and FIGS. 31A and 31B).
  • the supporting film was removed to some extent through an ashing process under an O 2 gas atmosphere so that the small LED devices were exposed from the supporting film. Power 50W, working pressure 0.05torr, O 2 100sccm ). Subsequently, a binder (PMMA, 1.5-2.0 ⁇ m thick) to bundle the ultra-small LED devices was coated on the LED devices (see FIG. 32).
  • the binder in order to form the electrode on the first conductive semiconductor layer, the binder is ashed and removed in an O 2 gas atmosphere until the semiconductor layer is exposed (power 50W, working pressure 0.05torr, O 2 100sccm), and the electrode (Ti ) Was deposited (300V, 0.17A, Ar 100sccm) (see FIG. 33).
  • nonaneedithiol was coated on the surface of the electrode as a bonding linker by liquid or gas phase self-assembly.
  • the coating process was performed in the liquid phase, 1mM nonanedithiol solution was prepared by mixing ethanol anhydride (10ml) and nonanedithiol (20 ⁇ l), and the ultra-small LED rod form on which the electrode was deposited was added to the nonanedithiol solution. After soaking for one day, the micro LED rod was taken out and washed. The support film was removed using acetone to prepare bundled ultra-small LED devices in the form of ink or paste (see FIGS. 34A and 34B). The ink or paste was aligned by dropping onto an electrode substrate having a linker (metal fine powder: silver nanoparticles) that reacted with its binding linker (nonanedithiol linker).
  • a linker metal fine powder: silver nanoparticles
  • a pattern was formed by patterning on the electrode using silver nanoparticles, which are fine metal powders that can react with the dithiol linker reacting with the electrode substrate and the coupling linker of the micro LED.
  • the nonanedithiol linker was first reacted with the electrode substrate, and then coated with silver nanoparticles on the opposite side of the nonanedithiol linker, which is not attached to the electrode substrate.
  • the coating was carried out by taking an electrode substrate having a nonanedithiol linker in a toluene solution in which silver nanoparticles were dispersed, and then removing the electrode substrate.
  • the ultra-small LED device bundle according to the present invention is formed by forming a metal ohmic layer through a soldering process (annealing process of 100 ⁇ 200 °C) Prepared (see Figure 35).
  • FIG. 36 illustrates a spectrum measured after aligning the ultra-small LED devices manufactured as described above to an electrode substrate, and also visually observed photographs of the micro LED devices manufactured in FIGS. 37A to 37C. As can be seen from the drawings, it can be seen that the blue light is emitted from the ultra-small LED device bundle according to the present invention.
  • micro LED device according to the present invention can be widely used throughout the display industry.

Abstract

The present invention relates to a micro LED bundle and to a method for manufacturing same, and more specifically, to a micro LED bundle, comprising: a first conductive semiconductor layer; an active layer which is formed on the first conductive semiconductor layer; and a plurality of micro LEDs having a diameter which is micro- or nano-sized and including a second conductive layer that is formed on the active layer, wherein the plurality of micro LEDs are provided with a binder on the outer circumferential surfaces thereof to form one bundle, and to a method for manufacturing the micro LED comprising the following steps: 1) sequentially forming the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer, on a substrate; 2) forming the plurality of micro LEDs by etching the LEDs comprising the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer so that the diameters of the LEDs are in the nano or micro size range; and 3) forming a plurality of bundles by forming the binder on the outer circumferential surfaces of the plurality of LEDs. According to the present invention, the nano- or micro-sized micro LED can be effectively produced by combining a top-down method and a bottom-up method, and the light emitting efficiency can be improved by preventing surface defects on the micro LEDs that are produced.

Description

초소형 LED 소자 번들 및 그 제조방법Micro LED Bundle and Manufacturing Method
본 발명은 초소형 LED 소자 번들 및 그 제조방법에 관한 것으로, 보다 상세하게는 초소형 LED 소자를 보다 용이하게 취급할 수 있으며, 디스플레이 기판에 부착시 불량률을 최소화할 수 있는 초소형 LED 소자 번들 및 그 제조방법에 관한 것이다.The present invention relates to an ultra-small LED device bundle and a method of manufacturing the same, and more particularly to an ultra-small LED device bundle and a method for manufacturing the ultra-small LED device that can minimize the defect rate when attached to the display substrate. It is about.
현재 큰 밴드갭을 가진 질화물계 반도체를 이용하여 질화물계 반도체 성장 구조나 성장된 박막의 제작공정을 개선시켜 광변환 효율이 높은 발광 소자(LED: light emitting diode)를 개발하려는 노력이 활발히 이루어지고 있다.Currently, efforts are being made to develop a light emitting diode (LED) having high light conversion efficiency by improving a nitride semiconductor growth structure or a manufacturing process of a grown thin film using a nitride semiconductor having a large band gap. .
그런데, 지금까지 알려진 LED TV는 기존의 LCD TV에 사용되는 냉음극형광등 (cold cathode fluorescent lamp, CCFL) 백라이트를 대신해 백색 또는 삼원색 LED 소자를 백라이트로 채용한 LCD TV로서, 정확하게 말하면 LED 백라이트를 사용한 LCD TV이다. 구체적으로, 현재 상용화된 풀칼라 LED 디스플레이는 초대형 기판에 적, 녹, 청 3원색 LED 램프를 수만개에서 수십만 개 이상 삽입한 옥외전광판용 디스플레이가 유일하게 일상에서 접할 수 있는 제품이다. 따라서, 현재까지는 진정한 의미의 LED 풀칼라 디스플레이를 가정용 TV나 컴퓨터용 모니터로는 구현하지 못하고 있다. By the way, known to date LED TV is LCD as a LCD TV employing a cold cathode fluorescent lamp (cold cathode fluorescent lamp, CCFL) white or tri-color LED devices on behalf of the backlight in the backlight used in conventional LCD TV, precisely with the LED back light TV. Specifically, the current commercially available full-color LED display is the only product that can be encountered in everyday life, the display for outdoor billboards in which tens of thousands to hundreds of thousands of red, green and blue three-color LED lamps are inserted into a very large substrate. Thus, until now, a full-featured LED full-color display has not been realized as a home TV or computer monitor.
기존의 LED 소자를 이용해서 TV나 모니터급 사이즈의 디스플레이로 발전시키지 못하는 이유는 LED 소자를 이용해서 디스플레이를 제조하는 기술적 방법과 풀칼라를 구현하는 방법의 근본적인 한계에 기인한다. 기존 LED 소자의 제조방법은 2 ~ 8 인치 사이즈의 사파이어 기판에 금속 유기물 화학 증착 (metal organic chemical vapor deposition: MOCVD) 방법으로 III-V족 물질의 p-반도체층, 양자우물층, n-반도체층 들을 증착시킨 후, 절단/배선/패키징 등의 다양한 후공정을 통해서 필요한 형태의 LED 소자를 제조하는 방법이다. 이러한 방법을 사용해서 직접 TV용 디스플레이를 만들 경우, 단순히 계산해보면 2 ~ 8 인치 웨이퍼를 5 ~ 40 장 연결해야만 40인치 급 TV를 제작할 수 있다. 따라서, 현재 알려진 제조기술을 사용해서 LED소자로 직접 TV급 디스플레이를 실현하는 데는 현재의 기술로는 극복할 수 없는 수 많은 문제점들이 산재해 있다. 이와 더불어, 풀칼라를 구현하기 위해서는 적, 녹, 청 3원색 LED 소자를 한 개의 픽셀 (pixel)에 같이 박아 넣어야 하므로 단순히 적, 녹, 청 LED 웨이퍼를 이어 붙여서는 LED 풀칼라 디스플레이를 구현할 수 없다. The reason why the existing LED device cannot be developed into a TV or monitor size display is due to the fundamental limitation of the technical method of manufacturing the display using the LED device and the method of implementing full color. Conventional LED device manufacturing method is a metal organic chemical vapor deposition (MOCVD) method on the sapphire substrate of 2 ~ 8 inches size p-semiconductor layer, quantum well layer, n-semiconductor layer of III-V material After depositing these, it is a method of manufacturing the LED device of the required form through various post-processing such as cutting / wiring / packaging. If you build your own display for a TV using this method, you can simply calculate the 40-inch TV only by connecting 5 to 40 sheets of 2 to 8 inch wafers. Therefore, there are a number of problems scattered in the current technology to realize a TV-class display directly using LED devices using current manufacturing technology. In addition, in order to realize full color, red, green, and blue primary LED devices must be embedded together in one pixel, so it is impossible to realize LED full color display by simply connecting red, green, and blue LED wafers together. .
고효율 LED 디스플레이를 실현하기 위해서는 실제 디스플레이용 대면적 유리기판의 패턴된 픽셀 위치에 III-V족 박막 및 나노로드 LED 소자를 직접 성장시키는 바텀-업 (bottom-up) 방법이 있다. 지금까지 많은 연구를 통해서 알려진 바에 의하면, III-V 족 박막을 성장시키는 MOCVD 방법으로는 TV용 디스플레이급 사이즈와 같은 대형기판에 직접 증착하는 공정은 설비상 불가능한 것으로 알려져 있다. 이 뿐만 아니라, 투명한 비결정질 유리기판에 패턴된 투명전극 위에 고결정성/고효율 III-V족 박막 및 나노로드 헤테로접합 (heterojunction) LED 소자를 성장시키는 것 역시 결정학적으로도 매우 어려운 것으로 알려져 있다. 이와 같은 기술적 한계 때문에 작은 소자를 제외하고 대면적 유리기판에 LED 소자를 직접 성장시켜서 TV 또는 모니터급 풀칼라 디스플레이를 구현하는 방법은 거의 시도되지 않고 있다.To realize high-efficiency LED displays, there is a bottom-up method of directly growing III-V thin film and nanorod LED devices at patterned pixel positions of large-area glass substrates for actual displays. It is known that the process of directly depositing on a large substrate such as a display size for TV is impossible in the MOCVD method of growing III-V thin film. Not only that, it is also known to grow a high crystalline / high efficiency group III-V thin film and nanorod heterojunction LED device on a transparent electrode patterned on a transparent amorphous glass substrate. Due to these technical limitations, except for small devices, a method of realizing a TV or monitor-class full-color display by directly growing LED devices on a large-area glass substrate has not been attempted.
LED 디스플레이를 실현하기 위해서 많은 연구자들에 의해서 추진되고 있는 또 다른 접근법은 나노기술을 기반으로 한 바텀-업 방식이다. 이 방법은 단결정 기판 위에 나노로드형 LED를 성장시킨 후, 일부를 떼어 내어서 픽셀로 패턴된 전극 위에 바텀-업 방식으로 재배열시킴으로써, 대면적 디스플레이를 구현하는 방법이다. 하지만, 이와 같이 바텀-업 방식으로 제조한 나노로드 LED는 기존에 웨이퍼에 성장시킨 박막형 LED에 비교하여 발광효율이 형편없이 떨어지므로, 이 기술로 LED 디스플레이를 구현하더라도 상당한 기간 동안 효율 저하의 문제점을 해결할 수 없다. 뿐만 아니라, 바텀-업 방식으로 성장시킨 나노로드 LED 소자를 바텀-업 방식의 자기조립법으로 전극위에 배열하기 위해서는 사이즈와 높이가 균일한 나노로드 소자를 얻는 것이 필수적이다. 하지만, 잘 알려진 기상-액상-고상 (Vapor-Liquid-Solid: VLS) 방법과 같은 나노로드 성장법을 이용해서 자기조립에 용이한 균일한 사이즈와 특성을 갖는 나노로드 LED 소자를 대량으로 제조할 가능성이 매우 적다.Another approach being pushed by many researchers to realize LED displays is a bottom-up approach based on nanotechnology. This method is a method of realizing a large-area display by growing a nanorod type LED on a single crystal substrate, and then removing a portion and rearranging it in a bottom-up manner on an electrode patterned with pixels. However, since the nanorod LED manufactured by the bottom-up method has poor luminous efficiency compared to the thin film LEDs grown on the wafer, even if the LED display is implemented with this technology, there is a problem of efficiency degradation for a considerable period of time. Can't solve it. In addition, in order to arrange the nanorod LED device grown in the bottom-up method on the electrode by the bottom-up self-assembly, it is essential to obtain a nanorod device having a uniform size and height. However, using nanorod growth methods such as the well-known Vapor-Liquid-Solid (VLS) method, it is possible to mass-produce nanorod LED devices with uniform size and characteristics that are easy to self-assemble. This is very small.
또 다른 방법으로는, 고효율 LED 소자를 잘라서 LED 디스플레이를 구현하는 탑-다운 (top-down) 방법이 있다. 일반적으로, 이 방법은 대면적 유리 기판의 써브-픽셀 위치에 탑-다운 방식으로 제조한 마이크로 LED 소자를 한 개씩 배열하는 일대일 대응 방식으로 디스플레이를 구현하는 방법이다. 구체적으로, 마이크로 사이즈의 LED 디스플레이의 경우는 탑-다운 방식으로 제조한 개개의 마이크로 LED를 각각의 써브-픽셀로 제작하므로, 소형 마이크로 LED 디스플레이용으로 개발되었다. 이 경우 LED 소자를 사파이어 기판에 성장시킨 후, 마이크로 사이즈로 패터닝하여 마이크로 LED 소자를 제조한 후 전극을 배선하므로 웨이퍼 기판사이즈보다 적은 마이크로 LED 디스플레이를 구현한다. 이 방법을 이용할 경우, 효율에는 문제가 없으나, 기판 사이즈 및 제조 공정의 한계로 대면적 사이즈의 LED 디스플레이를 구현하는 것은 불가능하다.Another method is a top-down method that cuts high-efficiency LED devices to create an LED display. In general, this method is a method of implementing a display in a one-to-one correspondence method in which micro-LED devices manufactured in a top-down manner are arranged one by one in a sub-pixel position of a large area glass substrate. Specifically, in the case of the micro-sized LED display, the individual micro LEDs manufactured by the top-down method are manufactured for each sub-pixel, and thus, were developed for the small micro LED display. In this case, the LED device is grown on a sapphire substrate, and then patterned to a micro size to manufacture a micro LED device, and then the electrodes are wired to implement a micro LED display smaller than the wafer substrate size. If this method is used, there is no problem in efficiency, but it is impossible to realize a large-area LED display due to limitations in substrate size and manufacturing process.
결국, 종래의 탑-다운 또는 바텀-업 방식으로 제조한 초소형 LED 소자는 에칭작업에 의한 표면 결함의 증가로 효율 및 안정성 저하의 문제가 발생할 가능성이 매우 높다. 또한, 독립된 초소형 LED 소자의 경우, 초소형 소자간의 표면 극성으로 인해서 상호 응집력이 발생하고 응집체가 형성되며, 그에 따른 픽셀 패터닝 공정에서 다수의 불량을 초래할 수 있다. 따라서, 독립된 초소형 마이크로 LED 소자의 제조만으로 양산성 있는 고효율/대면적 LED 디스플레이 소자를 구현하는 데는 한계가 있다. As a result, the ultra-small LED device manufactured by the conventional top-down or bottom-up method is very likely to cause problems of efficiency and stability due to an increase in surface defects caused by etching. In addition, in the case of an independent micro LED device, due to the surface polarity between the micro devices, mutual cohesion occurs and aggregates are formed, which may result in a large number of defects in the pixel patterning process. Therefore, there is a limitation in implementing mass-efficient high efficiency / large-area LED display devices only by manufacturing independent micromini LED devices.
나아가, 종래의 방법으로 제조된 초소형 LED 소자를 LED 디스플레이 기판의 서브픽셀 (픽셀위치)에 위치시키는 경우, LED 소자의 크기가 너무 작으므로 LED 디스플레이의 서브픽셀 상에 초소형 LED 소자가 바로서지 못하고 옆으로 눕거나 뒤집혀서 위치하게 되는 문제가 있었다.Furthermore, when the ultra-small LED device manufactured by the conventional method is placed in a subpixel (pixel position) of the LED display substrate, the micro LED device is too small to stand on the subpixel of the LED display because the size of the LED device is too small. There was a problem of lying down or upside down.
본 발명은 상술한 문제점을 해결하기 위해 안출된 것으로, 본 발명의 첫 번째 기술적 과제는, 초소형 LED 소자의 에칭작업에 의한 표면 결함의 증가로 효율 및 안정성 저하 및 초소형 LED 소자간의 응집 문제를 해결할 수 있는 초소형 LED 소자 번들의 제조방법을 제공하는 것이다.The present invention has been made to solve the above-mentioned problems, the first technical problem of the present invention, the surface defects caused by the etching operation of the small LED device can be solved the problem of efficiency and stability and the cohesion between the small LED device due to the increase in surface defects It is to provide a method of manufacturing a small LED device bundle.
본 발명의 두 번째 기술적 과제는, LED 디스플레이의 서브픽셀 (픽셀위치) 상에서 초소형 LED 소자가 옆으로 눕거나 뒤집히지 않고 정확하게 위치할 수 있는 초소형 LED 소자 번들을 제공하는 것이다.A second technical problem of the present invention is to provide a micro LED bundle that enables the micro LED device to be accurately positioned without lying on its side or flipped over on a subpixel (pixel position) of the LED display.
본 발명은 상기 첫 번째 기술적 과제를 해결하기 위해서,The present invention to solve the first technical problem,
1) 기판 위에 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 순차적으로 형성하는 단계; 2) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 포함하는 LED 소자의 직경이 나노 또는 마이크로 크기를 가지도록 식각함으로써, 복수개의 초소형 LED 소자를 형성하는 단계; 및 3) 상기 복수개의 초소형 LED 소자의 외주면에 바인더를 형성함으로써, 복수개의 번들(bundle)을 형성하는 단계를 포함하는 초소형 LED 소자 번들의 제조방법을 제공한다.1) sequentially forming a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer on the substrate; 2) forming a plurality of ultra-small LED devices by etching the diameter of the LED device including the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer to have a nano or micro size; And 3) forming a plurality of bundles by forming a binder on the outer circumferential surface of the plurality of micro LEDs, thereby providing a method of manufacturing a micro LED bundle.
본 발명의 일 실시예에 따르면, 상기 제1 도전성 반도체층은 적어도 하나의 n형 반도체층을 포함하고, 상기 제2 도전성 반도체층은 적어도 하나의 p형 반도체층을 포함할 수 있다.According to an embodiment of the present invention, the first conductive semiconductor layer may include at least one n-type semiconductor layer, and the second conductive semiconductor layer may include at least one p-type semiconductor layer.
본 발명의 다른 실시예에 따르면, 상기 2) 단계는;According to another embodiment of the invention, the step 2) is;
2-1) 제2 도전성 반도체층의 위에 제2 전극층, 절연층 및 금속 마스크층을 순차적으로 형성하는 단계; 2-2) 상기 금속 마스크층 위에 폴리머층을 형성하고 상기 폴리머층에 나노 또는 마이크로 간격으로 패턴을 형성하는 단계; 2-3) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 패턴에 따라 나노 또는 마이크로 간격으로 건식 또는 습식 식각하는 단계; 및 2-4) 상기 절연층, 금속 마스크층 및 폴리머층을 제거하는 단계를 포함할 수 있다.2-1) sequentially forming a second electrode layer, an insulating layer, and a metal mask layer on the second conductive semiconductor layer; 2-2) forming a polymer layer on the metal mask layer and forming a pattern on the polymer layer at nano or micro intervals; 2-3) dry or wet etching the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer at nano or micro intervals according to a pattern; And 2-4) removing the insulating layer, the metal mask layer, and the polymer layer.
본 발명의 또 다른 실시예에 따르면, 상기 2) 단계는;According to another embodiment of the present invention, the step 2);
2-5) 제2 도전성 반도체층의 위에 제2 전극층, 절연층 및 금속 마스크층을 형성하는 단계; 2-6) 상기 금속 마스크층 위에 나노스피어 또는 마이크로스피어 단층막을 형성하고 자기조립을 수행하는 단계; 2-7) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 패턴에 따라 나노 또는 마이크로 간격으로 건식 또는 습식 식각하는 단계; 및 2-8) 상기 절연층, 금속 마스크층 및 단층막을 제거하는 단계를 포함할 수 있다.2-5) forming a second electrode layer, an insulating layer, and a metal mask layer on the second conductive semiconductor layer; 2-6) forming a nanosphere or microsphere monolayer on the metal mask layer and performing self-assembly; 2-7) dry or wet etching the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer at nano or micro intervals according to a pattern; And 2-8) removing the insulating layer, the metal mask layer, and the single layer film.
본 발명의 또 다른 실시예에 따르면, 상기 나노스피어 또는 마이크로스피어는 폴리스티렌 재질일 수 있다.According to another embodiment of the present invention, the nanospheres or microspheres may be a polystyrene material.
본 발명의 또 다른 실시예에 따르면, 상기 3) 단계는; 3-1) 제2 전극층의 위에 지지필름을 형성하는 단계; 3-2) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 포함하는 외주면에 절연피막을 형성하는 단계; 3-3) 상기 기판을 제거하는 단계; 3-4) 절연피막이 형성된 상기 복수개의 초소형 LED 소자들의 외주면에 바인더를 형성하여 복수개의 번들(bundle)을 형성하는 단계; 3-5) 상기 제1 도전성 반도체층의 하부에 제1 전극을 형성하는 단계; 3-6) 상기 제1 도전성 반도체층의 하부에 형성된 제1 전극에 자기조립을 위하여 결합링커를 부착하는 단계; 및 3-7) 상기 지지필름을 제거하여 복수개의 초소형 LED 소자 번들을 제조하는 단계를 포함할 수 있다.According to another embodiment of the present invention, step 3) is performed; 3-1) forming a supporting film on the second electrode layer; 3-2) forming an insulating film on an outer circumferential surface including the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer; 3-3) removing the substrate; 3-4) forming a plurality of bundles by forming a binder on an outer circumferential surface of the plurality of ultra-small LED elements having an insulating film formed thereon; 3-5) forming a first electrode under the first conductive semiconductor layer; 3-6) attaching a coupling linker for self-assembly to the first electrode formed under the first conductive semiconductor layer; And 3-7) manufacturing the plurality of micro LED bundles by removing the support film.
본 발명의 또 다른 실시예에 따르면, 상기 바인더는 소수성이며, 상기 복수개의 번들 중 하나의 번들은 5 ~ 100 개의 초소형 LED 소자를 포함할 수 있다.According to another embodiment of the present invention, the binder is hydrophobic, and one of the plurality of bundles may include 5 to 100 micro LEDs.
또한, 본 발명은 상기 두 번째 과제를 해결하기 위해서,In addition, the present invention to solve the second problem,
제1 도전성 반도체층; 상기 제1 도전성 반도체층 위에 형성된 활성층; 상기 활성층 위에 형성된 제2 도전성 반도체층을 포함하는 직경이 마이크로 또는 나노 크기의 복수개의 초소형 LED 소자를 포함하며, 상기 복수개의 초소형 LED 소자는 그 외주면에 바인더가 형성되어 하나의 번들(bundle)을 형성하는 초소형 LED 소자 번들을 제공한다.A first conductive semiconductor layer; An active layer formed on the first conductive semiconductor layer; A plurality of micro LED devices having a diameter of a micro or nano size including a second conductive semiconductor layer formed on the active layer, the plurality of micro LED devices is a binder formed on the outer peripheral surface to form a bundle Provides a compact LED device bundle.
본 발명의 일 실시예에 따르면, 상기 바인더는 소수성이며, 하나의 번들은 5 ~ 100개의 초소형 LED 소자를 포함할 수 있다.According to an embodiment of the present invention, the binder is hydrophobic, and one bundle may include 5 to 100 micro LEDs.
본 발명의 다른 실시예에 따르면, 상기 제1 도전성 반도체층의 하부에는 제1 전극층이 형성되고, 상기 제2 도전성 반도체층의 상부에는 제2 전극층이 형성될 수 있다.According to another embodiment of the present invention, a first electrode layer may be formed below the first conductive semiconductor layer, and a second electrode layer may be formed above the second conductive semiconductor layer.
본 발명의 또 다른 실시예에 따르면, 상기 초소형 LED 소자는 바인더의 내부에 형성된 절연피막을 포함할 수 있다.According to another embodiment of the present invention, the micro LED device may include an insulating film formed inside the binder.
본 발명의 또 다른 실시예에 따르면, 상기 제1전극층의 하부면 및 제2 전극층의 상부면 중 적어도 하나의 전극층의 표면에 결합링커를 포함할 수 있다.According to another embodiment of the present invention, a coupling linker may be included on the surface of at least one electrode layer of the lower surface of the first electrode layer and the upper surface of the second electrode layer.
본 발명의 또 다른 실시예에 따르면, 상기 결합링커는 LED 디스플레이의 기판과 상보적으로 결합할 수 있다.According to another embodiment of the present invention, the coupling linker may be complementarily coupled to the substrate of the LED display.
본 발명의 또 다른 실시예에 따르면, 상기 제1 도전성 반도체층은 적어도 하나의 n형 반도체층을 포함하고, 상기 제2 도전성 반도체층은 적어도 하나의 p형 반도체층을 포함할 수 있다.According to another embodiment of the present invention, the first conductive semiconductor layer may include at least one n-type semiconductor layer, and the second conductive semiconductor layer may include at least one p-type semiconductor layer.
본 발명의 또 다른 실시예에 따르면, 상기 바인더는 감광성 폴리머 및 스핀-온-글래스 (Spin-on-glass)로 이루어지는 군으로부터 선택된 하나 이상의 물질을 포함할 수 있다.According to another embodiment of the present invention, the binder may include one or more materials selected from the group consisting of a photosensitive polymer and spin-on-glass.
이하, 본 발명에 있어서, 각 층 (막), 영역, 패턴 또는 구조물들이 기판, 각 층 (막), 영역, 패턴들의 "위(on)"에 또는 "아래(under)"에 형성되는 것으로 기재되는 경우에 있어, "위(on)"와 "아래(under)"는 "직접적으로 (directly)"와 "간접적으로 (indirectly)"의 의미를 모두 포함한다. 또한, 각 층의 위 또는 아래에 대한 기준은 도면을 기준으로 설명한다.Hereinafter, in the present invention, each layer (film), region, pattern or structures is described as being formed on or "under" a substrate, each layer (film), region, or pattern. In this case, the terms "on" and "under" include both "directly" and "indirectly". In addition, the reference | standard about the top or bottom of each layer is demonstrated based on drawing.
본 발명에 따른 초소형 LED 소자의 제조방법은 종래 초소형 LED 소자의 문제점이었던, 에칭작업에 의한 표면 결함 증가, 그에 따른 효율 및 안정성 저하 및 초소형 LED 소자간의 응집문제를 해결할 수 있다.The manufacturing method of the ultra-small LED device according to the present invention can solve the problem of cohesion between the ultra-small LED device, the surface defects increase due to the etching operation, thereby reducing efficiency and stability and the ultra-small LED device.
또한, 본 발명에 따르면, 크기가 매우 작은 초소형 LED 소자의 취급을 용이하게 할 수 있을 뿐 아니라, LED 디스플레이의 서브픽셀(픽셀위치) 상에서 초소형 LED 소자가 옆으로 눕거나 뒤집히지 않고 정확하게 위치할 수 있어 LED 디스플레이의 효율을 획기적으로 개선할 수 있다.Further, according to the present invention, it is not only easy to handle very small LED elements, but also it is possible to accurately position the LED elements on a subpixel (pixel position) of the LED display without lying on its side or upside down. This can dramatically improve the efficiency of the LED display.
도 1은 본 발명의 일 실시예에 따른 LED 기본소자층을 형성하는 단계를 나타내는 단면도이다.1 is a cross-sectional view showing a step of forming an LED basic device layer according to an embodiment of the present invention.
도 2는 본 발명의 제2 도전성 반도체층 위에 제2 전극층, 절연층 및 금속 마스크층을 형성하는 단계를 나타내는 단면도이다.2 is a cross-sectional view illustrating a step of forming a second electrode layer, an insulating layer, and a metal mask layer on a second conductive semiconductor layer of the present invention.
도 3은 본 발명의 금속 마스크층 위에 나노스피어 또는 마이크로스피어 단층막을 형성하는 단계를 나타내는 단면도이다.3 is a cross-sectional view showing a step of forming a nanosphere or microsphere monolayer film on the metal mask layer of the present invention.
도 4는 본 발명의 나노스피어 또는 마이크로스피어 단층막의 애싱 (ashing) 단계를 나타내는 단면도이다.4 is a cross-sectional view showing the ashing step of the nanospheres or microspheres monolayer film of the present invention.
도 5는 본 발명의 식각단계를 나타내는 단면도이다.5 is a cross-sectional view showing an etching step of the present invention.
도 6은 본 발명의 스피어 단층막, 금속 마스크층 및 절연층을 제거하는 단계를 나타내는 단면도이다.6 is a cross-sectional view showing a step of removing a spear monolayer film, a metal mask layer, and an insulating layer of the present invention.
도 7은 본 발명의 제2 전극층 위에 지지필름을 부착하는 단계를 나타내는 단면도이다.7 is a cross-sectional view showing a step of attaching a support film on the second electrode layer of the present invention.
도 8은 본 발명의 개개의 LED 소자의 외주면에 절연피막을 코팅하는 단계를 나타내는 도면이다.8 is a view showing a step of coating an insulating film on the outer circumferential surface of each LED device of the present invention.
도 9는 본 발명의 LED 소자의 외주면에 형성된 절연피막을 소수성 피막으로 코팅하는 단계를 나타내는 단면도이다.9 is a cross-sectional view showing a step of coating the insulating film formed on the outer peripheral surface of the LED device of the present invention with a hydrophobic film.
도 10은 본 발명의 LED 소자들의 외주면에 형성된 절연피막에 폴리머 바인더를 공통으로 연결하여 초소형 LED 소자 번들을 제조하는 단계를 나타내는 도면이다.FIG. 10 is a view illustrating a step of manufacturing a micro LED device bundle by commonly connecting a polymer binder to an insulating film formed on outer surfaces of the LED devices of the present invention.
도 11은 본 발명의 기판이 제거된 제1 도전성 반도체층의 아래에 전극을 증착하는 단계를 나타내는 단면도이다.11 is a cross-sectional view illustrating depositing an electrode under a first conductive semiconductor layer from which a substrate of the present invention is removed.
도 12는 본 발명의 전극의 표면에 자기조립을 위한 결합링커를 코팅하는 단계를 나타내는 단면도이다.12 is a cross-sectional view showing a step of coating a coupling linker for self-assembly on the surface of the electrode of the present invention.
도 13은 본 발명의 지지필름을 제거하여 독립적인 초소형 LED 소자들을 제조하는 단계를 나타내는 단면도이다.13 is a cross-sectional view showing a step of manufacturing the independent ultra-small LED device by removing the support film of the present invention.
도 14는 본 발명의 LED 소자들의 외주면에 바인더를 공통으로 연결하여 제조된 초소형 LED 소자 번들을 나타내는 사시도이다.FIG. 14 is a perspective view illustrating an ultra-small LED device bundle manufactured by commonly connecting a binder to the outer circumferential surfaces of the LED devices of the present invention.
도 15는 본 발명의 개개의 LED 소자의 외주면에 절연피막을 형성하고, 이를 바인더로 연결하여 제조된 초소형 LED 소자 번들을 나타내는 사시도이다.FIG. 15 is a perspective view illustrating an ultra-small LED device bundle manufactured by forming an insulating film on an outer circumferential surface of each LED device of the present invention and connecting the same with a binder.
도 16은 본 발명의 전극의 표면에 자기조립을 위한 결합링커가 형성된 초소형 LED 소자를 나타내는 사시도이다.FIG. 16 is a perspective view of a micro LED device in which a coupling linker for self-assembly is formed on a surface of an electrode of the present invention. FIG.
도 17은 본 발명의 초소형 LED 소자 번들을 포함하는 잉크 또는 페이스트이다.FIG. 17 is an ink or paste containing the ultra-small LED device bundle of the present invention.
도 18은 본 발명의 LED 기본소자층 단면에 대한 전자현미경 관찰사진이다.18 is an electron microscope photograph of the cross-section of the LED basic device layer of the present invention.
도 19는 본 발명의 제2 도전성 반도체층 위에 절연층과 금속 마스크층을 형성한 단면에 대한 전자현미경 관찰사진이다.19 is an electron microscope photograph of a cross section in which an insulating layer and a metal mask layer are formed on a second conductive semiconductor layer of the present invention.
도 20a는 본 발명의 금속 마스크층 위에 나노스피어 단층막을 형성한 단면을 관찰한 전자현미경 사진이고, 도 20b는 그 평면을 관찰한 전자현미경 사진이다.20A is an electron microscope photograph of a cross section of a nanosphere monolayer film formed on a metal mask layer of the present invention, and FIG. 20B is an electron microscope photograph of a plane thereof.
도 21a는 본 발명의 나노스피어 단층막을 O2 가스 분위기 하에서 애싱 처리한 단면을 관찰한 전자현미경 사진이고, 도 21b는 그 평면을 관찰한 전자현미경 사진이다.Fig. 21A is an electron microscope photograph of a cross section obtained by ashing the nanosphere monolayer film of the present invention under an O 2 gas atmosphere, and Fig. 21B is an electron microscope photograph of the plane thereof.
도 22a는 본 발명의 크기가 축소된 나노스피어를 마스크로 하여 Cl2 가스 분위기 하에서 금속 마스크층을 에칭한 단면을 관찰한 전자현미경 사진이고, 도 22b는 그 평면을 관찰한 전자현미경 사진이다.FIG. 22A is an electron microscope photograph of a cross-section of a metal mask layer etched in a Cl 2 gas atmosphere using a nanosphere of which the size of the present invention is reduced, and FIG. 22B is an electron microscope photograph of the plane thereof.
도 23a는 본 발명의 에칭 공정에 의해서 폴리스티렌의 모양 그대로 전사 (transfer)된 금속 마스크층 패턴의 단면을 관찰한 전자현미경 사진이고, 도 23b는 그 평면을 관찰한 전자현미경 사진이다.FIG. 23A is an electron microscope photograph of a cross section of a metal mask layer pattern transferred as it is in the shape of polystyrene by an etching process of the present invention, and FIG. 23B is an electron microscope photograph of a plane thereof.
도 24a는 본 발명의 금속 마스크층 패턴을 이용해서 CF4 및 O2 가스 분위기하에서 SiO2 (절연층)를 식각한 단면을 관찰한 전자현미경 사진이고, 도 24b는 그 평면을 관찰한 전자현미경 사진이다. 24A is an electron microscope photograph of a cross section obtained by etching SiO 2 (insulating layer) under CF 4 and O 2 gas atmospheres using the metal mask layer pattern of the present invention, and FIG. 24B is an electron microscope photograph of the plane thereof. to be.
도 25a는 본 발명의 식각된 절연층을 이용해서 SiCl4 및 Ar 가스 분위기 하에서 ICP 방법으로 식각한 단면을 관찰한 전자현미경 사진이고, 도 25b는 그 평면을 관찰한 전자현미경 사진이다.FIG. 25A is an electron microscope photograph of a section etched by the ICP method under an SiCl 4 and Ar gas atmosphere using the etched insulating layer of the present invention, and FIG. 25B is an electron microscope photograph of the plane.
도 26a는 본 발명의 마스크로 사용된 절연층을 제거한 후 단면을 관찰한 전자현미경 사진이고, 도 26b는 그 평면을 관찰한 전자현미경 사진이다.FIG. 26A is an electron micrograph of a cross-sectional view after removing an insulating layer used as a mask of the present invention, and FIG. 26B is an electron micrograph of a plane thereof.
도 27a 및 27b는 본 발명의 절연피막 (Al2O3)이 코팅된 반도체층에 소수성 피막 (옥타데실트리클로로실란)을 코팅하기 전 (27a) 및 코팅한 후 (27b)의 접촉각 (contact angle)을 측정한 도면이다.27A and 27B show contact angles before (27a) and after (27b) of coating the hydrophobic coating (octadecyltrichlorosilane) on the semiconductor layer coated with the insulating coating (Al 2 O 3 ) of the present invention. ) Is a drawing measured.
도 28a 및 28b는 본 발명의 지지 필름이 부착되지 않은 버퍼층 또는 언도프드 반도체층과 사파이어 기판 쪽으로 레이저를 이용한 리프트-오프 공정을 수행한 단면을 관찰한 전자현미경 사진이다.28A and 28B are electron micrographs of cross-sections of laser-lift-off processes using a buffer layer or an undoped semiconductor layer and a sapphire substrate to which the supporting film of the present invention is not attached.
도 29a 및 29b는 본 발명의 제1 도전성 반도체층이 노출되도록 하기 위해서 버퍼층 또는 언도프드 반도체층을 ICP 방법으로 어느 정도 식각한 단면을 관찰한 전자현미경 사진이다.29A and 29B are electron micrographs of a cross section obtained by etching the buffer layer or the undoped semiconductor layer to some extent in order to expose the first conductive semiconductor layer of the present invention.
도 30a 및 30b는 본 발명의 ICP 방법으로 더욱 식각을 진행한 후 단면을 관찰한 전자현미경 사진이다.30a and 30b are electron micrographs observed in cross section after further etching by the ICP method of the present invention.
도 31a는 본 발명의 ICP 방법으로 제1 도전성 반도체층이 노출되도록 식각된 단면을 관찰한 전자현미경 사진이고, 도 31b는 그 평면을 관찰한 전자현미경 사진이다.FIG. 31A is an electron microscope photograph of a cross section etched to expose a first conductive semiconductor layer by the ICP method of the present invention, and FIG. 31B is an electron microscope photograph of a plane thereof.
도 32는 본 발명의 바인더를 코팅하여 초소형 LED 소자를 번들형으로 제조한 단면을 전자현미경으로 관찰한 사진이다.32 is a photograph observing a cross-section of a micro LED device manufactured by coating a binder of the present invention in a bundle form with an electron microscope.
도 33은 본 발명의 바인더를 애싱 공정을 통해 조금 제거한 뒤, 제1 도전성 반도체 층에 스퍼터링 방법으로 전극(Ti)을 증착한 단면을 전자현미경으로 관찰한 사진이다.FIG. 33 is a photograph of an electron microscope of a cross section of the electrode Ti deposited on the first conductive semiconductor layer by a sputtering method after the binder of the present invention is slightly removed through an ashing process.
도 34a 및 34b는 본 발명의 지지 필름을 아세톤으로 제거한 번들형의 초소형 LED를 전자현미경으로 관찰한 사진이다.34A and 34B are photographs observed by electron microscopy of a bundle-type micro LED having the support film of the present invention removed with acetone.
도 35는 본 발명의 번들형의 초소형 LED 소자를 전극 기판에 정렬시킨 것을 전자현미경으로 관찰한 사진이다.35 is a photograph of observing the bundle-type microminiature LED device of the present invention on an electrode substrate with an electron microscope.
도 36은 본 발명의 번들형의 초소형 LED 소자들을 전극 기판에 정렬시킨 뒤 측정한 스펙트럼을 도시한 도면이다.36 is a diagram illustrating a spectrum measured after aligning the bundled microminiature LED elements of the present invention to an electrode substrate.
도 37a 내지 37c는 본 발명의 초소형 LED 번들이 청색 발광하는 모습을 육안으로 관찰한 사진이다.37A to 37C are photographs visually observing a state in which the ultra-small LED bundle of the present invention emits blue light.
이하, 첨부된 도면을 참조하여 본 발명을 보다 상세히 설명한다.Hereinafter, with reference to the accompanying drawings will be described the present invention in more detail.
상술한 바와 같이, 종래기술에 따라 제조된 초소형 LED 소자를 LED 디스플레이 기판의 서브픽셀(픽셀위치) 상에 위치시키는 경우, LED 소자의 크기가 너무 작으므로, LED 디스플레이의 서브픽셀 상에 초소형 LED 소자가 바로서지 못하고 옆으로 눕거나 뒤집혀서 위치하게 되는 문제가 있었다.As described above, when the ultra-small LED device manufactured according to the prior art is placed on the subpixel (pixel position) of the LED display substrate, the size of the LED device is too small, so the ultra-small LED device on the subpixel of the LED display There was a problem in that it could not be placed right sideways, lying sideways or upside down.
이에 본 발명에서는, 1) 기판 위에 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 순차적으로 형성하는 단계; 2) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 포함하는 LED 소자의 직경이 나노 또는 마이크로 크기를 가지도록 식각함으로써, 복수개의 초소형 LED 소자를 형성하는 단계; 및 3) 상기 복수개의 초소형 LED 소자의 외주면에 바인더를 형성함으로써, 복수개의 번들(bundle)을 형성하는 단계를 포함하는 초소형 LED 소자 번들의 제조방법을 제공함으로써 상술한 문제점을 해결하고자 한다.In the present invention, 1) forming a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer sequentially on the substrate; 2) forming a plurality of ultra-small LED devices by etching the diameter of the LED device including the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer to have a nano or micro size; And 3) forming a binder on an outer circumferential surface of the plurality of micro LEDs, thereby providing a method of manufacturing a micro LED bundle including a step of forming a plurality of bundles.
먼저, 1) 단계로서 기판위에 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 순차적으로 형성한다. 구체적으로, 도 1은 본 발명의 일구현예에 따른 LED 기본소자층을 형성하는 단계를 나타내는 단면도로서, 기판(10)위에 제1 도전성 반도체층(11), 활성층(12) 및 제2 도전성 반도체층(13)을 형성하는 단계를 포함한다.First, as step 1), a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer are sequentially formed on a substrate. Specifically, Figure 1 is a cross-sectional view showing the step of forming the LED elementary device layer according to an embodiment of the present invention, the first conductive semiconductor layer 11, the active layer 12 and the second conductive semiconductor on the substrate 10 Forming a layer (13).
상기 기판(10)은 사파이어 기판(Al203) 및 유리와 같은 투과성 기판이 사용될 수 있다. 또한, 상기 기판(10)은 GaN, SiC, ZnO, Si, GaP 및 GaAs, 도전성 기판 등으로 이루어진 군에서 선택될 수 있다. 이하, 실시예에서는 사파이어 기판의 예로 설명하기로 한다. 상기 기판(10)의 상면은 요철 패턴이 형성될 수도 있다.The substrate 10 may be a transparent substrate such as sapphire substrate (Al 2 O 3 ) and glass. In addition, the substrate 10 may be selected from the group consisting of GaN, SiC, ZnO, Si, GaP and GaAs, conductive substrates. Hereinafter, the embodiment will be described as an example of the sapphire substrate. An uneven pattern may be formed on the upper surface of the substrate 10.
상기 기판(10) 위에는 질화물 반도체가 성장되는데, 그 성장 장비는 전자빔 증착, 물리적 기상증착 (physical vapor deposition: PVD), 화학적 기상증착 (chemical vapor deposition: CVD), 플라즈마 레이저 증착 (plasma laser deposition: PLD), 이중형 열증착 (dual-type thermal evaporator), 스퍼터링(sputtering), 금속 유기 화학적 기상증착 (metal organic chemical vapor deposition: MOCVD) 등에 의해 형성할 수 있으나, 이러한 방법으로만 제한되는 것은 아니다.The nitride semiconductor is grown on the substrate 10, and the growth equipment includes electron beam deposition, physical vapor deposition (PVD), chemical vapor deposition (CVD), and plasma laser deposition (PLD). ), Dual-type thermal evaporator, sputtering, metal organic chemical vapor deposition (MOCVD), etc., but is not limited thereto.
상기 기판(10) 위에는 버퍼층(미도시) 및/또는 미도핑 반도체층(미도시)이 형성될 수 있다. 상기 버퍼층은 상기 기판(10)과의 격자 상수 차이를 줄여주기 위한 층으로서, GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN 중 적어도 하나로 형성될 수 있다. 상기 미도핑 반도체층은 미도핑 GaN층으로 구현될 수 있으며, 질화물 반도체가 성장되는 기판으로 기능하게 된다. 상기 버퍼층 및 미도핑 반도체층은 어느 한 층만 형성하거나, 두 층 모두 형성되거나 형성되지 않을 수도 있다.A buffer layer and / or an undoped semiconductor layer (not shown) may be formed on the substrate 10. The buffer layer may be formed of at least one of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN as a layer for reducing a difference in lattice constant from the substrate 10. The undoped semiconductor layer may be implemented as an undoped GaN layer, and functions as a substrate on which a nitride semiconductor is grown. The buffer layer and the undoped semiconductor layer may be formed of only one layer, or both layers may or may not be formed.
본 발명의 바람직한 일구현예에 따르면 상기 기판의 두께는 400 ~ 1500㎛일 수 있으나, 이에 제한되지 않는다.According to a preferred embodiment of the present invention, the thickness of the substrate may be 400 to 1500 μm, but is not limited thereto.
상기 기판(10) 위에는 제1 도전성 반도체층(11)이 형성된다. 상기 제1 도전성 반도체층(11)은 예컨대, n형 반도체층을 포함할 수 있는 데, 상기 n형 반도체층은 InxAlyGa1-x-yN (0≤x≤1, 0 ≤y≤1, 0≤x+y≤1)의 조성식을 갖는 반도체 재료 예컨대, InAlGaN, GaN, AlGaN, InGaN, AlN, InN 등에서 어느 하나 이상이 선택될 수 있으며, 제1 도전성 도펀트(예: Si, Ge, Sn 등)가 도핑될 수 있다. 본 발명의 바람직한 일구현예에 따르면, 상기 제1 도전성 반도체층의 두께는 1.5 ~ 5㎛일 수 있으나, 이에 제한되지 않는다.The first conductive semiconductor layer 11 is formed on the substrate 10. The first conductive semiconductor layer 11 may include, for example, an n-type semiconductor layer, and the n-type semiconductor layer may include InxAlyGa1-x-yN (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x At least one of a semiconductor material having a compositional formula of + y ≦ 1), for example, InAlGaN, GaN, AlGaN, InGaN, AlN, InN, or the like, may be selected, and the first conductive dopant (eg, Si, Ge, Sn, etc.) may be doped. Can be. According to a preferred embodiment of the present invention, the thickness of the first conductive semiconductor layer may be 1.5 to 5㎛, but is not limited thereto.
상기 활성층(12)은 상기 제1 도전성 반도체층(11) 위에 형성되며, 단일 또는 다중 양자 우물 구조로 형성될 수 있다. 상기 활성층(12)의 위 및/또는 아래에는 도전성 도펀트가 도핑된 클래드층(미도시)이 형성될 수도 있으며, 상기 도전성 도펀트가 도핑된 클래드층은 AlGaN층 또는 InAlGaN층으로 구현될 수 있다. 그 외에, AlGaN, AlInGaN 등의 물질도 활성층(12)으로 이용될 수 있음은 물론이다. 이러한 활성층(12)에서는 전계를 인가하였을 때, 전자-정공 쌍의 결합에 의하여 빛이 발생하게 된다. 본 발명의 바람직한 일구현예에 따르면 상기 활성층의 두께는 0.05 ~ 0.25㎛일 수 있으나, 이에 제한되지 않는다.The active layer 12 is formed on the first conductive semiconductor layer 11 and may be formed in a single or multiple quantum well structure. A cladding layer (not shown) doped with a conductive dopant may be formed on and / or under the active layer 12, and the cladding layer doped with the conductive dopant may be implemented as an AlGaN layer or an InAlGaN layer. In addition, materials such as AlGaN and AlInGaN may also be used as the active layer 12. In the active layer 12, when an electric field is applied, light is generated by the combination of the electron-hole pairs. According to a preferred embodiment of the present invention, the thickness of the active layer may be 0.05 to 0.25 μm, but is not limited thereto.
상기 활성층(12) 위에는 제2 도전성 반도체층(13)이 형성되며, 상기 제2 도전성 반도체층(13)은 적어도 하나의 p형 반도체층으로 구현될 수 있는데, 상기 p형 반도체층은 InxAlyGa1-x-yN (0≤x≤1, 0 ≤y≤1, 0≤x+y≤1)의 조성식을 갖는 반도체 물질 예컨대, InAlGaN, GaN, AlGaN, InGaN, AlN, InN 등에서 어느 하나 이상이 선택될 수 있으며, 제2 도전성 도펀트(예: Mg)가 도핑될 수 있다. 여기서, 발광 구조물은 상기 제1 도전성 반도체층(11), 상기 활성층(12), 상기 제2 도전성 반도체층(13)을 최소 구성 요소로 포함하며, 각 층의 위/아래에 다른 형광체층, 활성층, 반도체층 및/또는 전극층을 더 포함할 수도 있다. 본 발명의 바람직한 일구현예에 따르면 상기 제2 도전성 반도체층의 두께는 0.08 ~ 0.25㎛일 수 있으나, 이에 제한되지 않는다.A second conductive semiconductor layer 13 is formed on the active layer 12, and the second conductive semiconductor layer 13 may be implemented with at least one p-type semiconductor layer, wherein the p-type semiconductor layer is InxAlyGa1-x. Any one or more of semiconductor materials having a compositional formula of -yN (0≤x≤1, 0≤y≤1, 0≤x + y≤1), such as InAlGaN, GaN, AlGaN, InGaN, AlN, InN, etc., may be selected. The second conductive dopant (eg, Mg) may be doped. The light emitting structure includes the first conductive semiconductor layer 11, the active layer 12, and the second conductive semiconductor layer 13 as minimum components, and different phosphor layers and active layers above and below each layer. , May further include a semiconductor layer and / or an electrode layer. According to a preferred embodiment of the present invention, the thickness of the second conductive semiconductor layer may be 0.08 to 0.25 μm, but is not limited thereto.
다음, 2) 단계는 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 포함하여 LED 소자의 직경이 나노 또는 마이크로 크기를 가지도록 식각함으로써 복수개의 초소형 LED 소자들을 제조한다.Next, step 2) includes the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer to manufacture a plurality of micro LED devices by etching the diameter of the LED device to have a nano or micro size.
이를 위하여 본 발명의 바람직한 일구현예에 따르면, 2-5) 제2 도전성 반도체층의 위에 제2 전극층, 절연층 및 금속 마스크층을 형성하는 단계; 2-6) 상기 금속 마스크층 위에 나노스피어 또는 마이크로스피어 단층막을 형성하고 자기조립을 수행하는 단계; 2-7) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 패턴에 따라 나노 또는 마이크로 간격으로 건식 또는 습식 식각하는 단계; 및 2-8) 상기 절연층, 금속 마스크층 및 단층막을 제거하는 단계를 포함할 수 있다.To this end, according to a preferred embodiment of the present invention, 2-5) forming a second electrode layer, an insulating layer and a metal mask layer on the second conductive semiconductor layer; 2-6) forming a nanosphere or microsphere monolayer on the metal mask layer and performing self-assembly; 2-7) dry or wet etching the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer at nano or micro intervals according to a pattern; And 2-8) removing the insulating layer, the metal mask layer, and the single layer film.
구체적으로 도 2는 본 발명의 제2 도전성 반도체(13)층 위에 제2 전극층(20), 절연층(21) 및 금속 마스크층(22)을 형성하는 단계를 나타내는 단면도이다. 먼저, 제2 전극층(20)은 통상의 LED 소자에 사용되는 금속 또는 금속산화물을 이용할 수 있으며, 바람직하게는 Cr, Ti, Al, Au, Ni, ITO 및 이들의 산화물 또는 합금 등을 단독 또는 혼합하여 사용할 수 있으나, 이에 제한되지 않는다. 본 발명의 바람직한 일구현예에 따르면, 상기 금속 마스크층의 두께는 0.02 ~ 0.1㎛일 수 있으나, 이에 제한되지 않는다.2 is a cross-sectional view illustrating a step of forming the second electrode layer 20, the insulating layer 21, and the metal mask layer 22 on the second conductive semiconductor 13 layer of the present invention. First, the second electrode layer 20 may use a metal or a metal oxide used in a conventional LED device, preferably Cr, Ti, Al, Au, Ni, ITO and oxides or alloys thereof, alone or mixed. It can be used, but is not limited thereto. According to a preferred embodiment of the present invention, the thickness of the metal mask layer may be 0.02 ~ 0.1㎛, but is not limited thereto.
상기 제2 전극층(20) 위에 형성되는 절연층(21)은 제2 전극층, 제2 도전성 반도체층, 활성층 및 제1 도전성 반도체층의 연속적인 에칭을 위한 마스크의 역할을 수행할 수 있으며, 산화물 또는 질화물을 이용할 수 있고, 대표적인 예로, 실리콘 산화물(SiO2) 또는 실리콘 질화물(SiN)이 이용될 수 있으나, 이에 제한되는 것은 아니다.The insulating layer 21 formed on the second electrode layer 20 may serve as a mask for continuous etching of the second electrode layer, the second conductive semiconductor layer, the active layer, and the first conductive semiconductor layer. Nitride may be used, and as a representative example, silicon oxide (SiO 2 ) or silicon nitride (SiN) may be used, but is not limited thereto.
본 발명의 바람직한 일구현예에 따르면 상기 절연층의 두께는 0.5 ~ 1.5㎛일 수 있으나, 이에 제한되지 않는다.According to a preferred embodiment of the present invention, the thickness of the insulating layer may be 0.5 to 1.5㎛, but is not limited thereto.
상기 절연층(21)의 위에 형성되는 금속 마스크층(22)은 에칭을 위한 마스크층의 역할을 수행하는 것으로, 통상적으로 사용되는 금속을 이용할 수 있으며, 대표적인 예로, 크롬(Cr) 금속이 이용될 수 있으나, 이에 제한되는 것은 아니다. 본 발명의 바람직한 일구현예에 따르면, 상기 금속 마스크층의 두께는 30 ~ 150 nm일 수 있으나, 이에 제한되지 않는다.The metal mask layer 22 formed on the insulating layer 21 serves as a mask layer for etching, and may be a metal commonly used. For example, chromium (Cr) metal may be used. May be, but is not limited thereto. According to a preferred embodiment of the present invention, the thickness of the metal mask layer may be 30 ~ 150 nm, but is not limited thereto.
도 3은 본 발명의 금속 마스크층(22) 위에 나노스피어 또는 마이크로스피어 단층막(30)을 형성하는 단계를 나타내는 단면도이다. 구체적으로, 나노스피어 또는 마이크로스피어 단층막은 금속 마스크층(22)의 에칭을 위한 마스크 역할을 하기 위하여 형성하는 것으로서, 스피어 입자의 형성방법은 스피어의 자기조립 특성을 이용할 수 있다. 스피어들의 자기조립에 의한 완전한 한층의 구조 배열 형성을 위하여 물 표면위에 스피어를 일정한 속도로 띄어 보내어 서로 자기조립되도록 만든다. 물에서 퍼지면서 형성된 스피어 영역은 작고 불규칙적이기 때문에, 추가적인 에너지와 계면활성제를 가하여 크고 규칙적인 배열을 가진 스피어 1층을 형성하고, 상기 금속 마스크층(22) 위로 스피어 1층을 떠냄으로서 금속층 위에 규칙적으로 배열된 스피어 단층막을 형성할 수 있다. 스피어 입자의 직경은 최종 생산하려는 초소형 LED 소자의 원하는 직경에 따라 선택적으로 사용될 수 있으며, 바람직하게는 50 ~ 3000㎚의 직경을 갖는 폴리스티렌 스피어, 실리카 스피어 등을 사용할 수 있으나, 이에 제한되지 않는다.3 is a cross-sectional view showing a step of forming a nanosphere or microsphere monolayer film 30 on the metal mask layer 22 of the present invention. Specifically, the nanospheres or microspheres monolayer film is formed to serve as a mask for etching the metal mask layer 22, and the method of forming the sphere particles may use the self-assembly of the spheres. In order to form a complete structure arrangement by self-assembly of spears, the spears are sent on the surface of the water at a constant speed to self-assemble each other. Since the spheres formed while spreading in water are small and irregular, they are added regularly with additional energy and surfactants to form a large, regular array of spheres, and the regular spheres on the metal layer by floating one layer of spheres over the metal mask layer 22. The spear monolayer film can be formed. The diameter of the sphere particles can be selectively used according to the desired diameter of the ultra-small LED device to be produced, preferably polystyrene spheres, silica spheres and the like having a diameter of 50 ~ 3000nm, but is not limited thereto.
도 4는 본 발명의 나노스피어 또는 마이크로스피어 단층막(30)의 애싱(ashing) 단계를 나타내는 단면도로서, 스피어 입자의 간격이 이격된다. 통상의 스피어 단층막의 애싱공정을 통해 달성될 수 있으며, 바람직하게는, 산소(O2) 기반의 반응성 이온 애싱 (Reactive ion ashing)과 플라즈마 애싱 (plasma ashing)을 통해서 (예: 가열) 애싱공정이 수행될 수 있다.4 is a cross-sectional view showing the ashing step of the nanospheres or microspheres monolayer film 30 of the present invention, the spacing of the sphere particles are spaced apart. It can be achieved through an ashing process of a conventional spear monolayer film, and preferably, an ashing process (eg, heating) is performed through oxygen (O 2 ) -based reactive ion ashing and plasma ashing. Can be performed.
도 5는 본 발명의 식각단계를 나타내는 단면도로서, 구체적으로 도 4에서 애싱공정을 통해 이격된 스피어 입자 사이를 식각하여 홀을 형성하는 공정이다. 이 경우, 스피어 입자(30)가 형성된 부분은 식각되지 않고 스피어 입자와 스피어 입자 사이의 이격된 공간부분이 식각되어 홀을 형성한다. 상기 홀은 금속 마스크층(22)부터 기판(10)의 위까지 선택적으로 형성될 수 있다. 이러한 식각공정은 반응성 이온 에칭 (reactive ion etching: RIE) 또는 유도 결합 플라즈마 반응성 이온 에칭 (inductively coupled plasma reactive ion etching: ICP-RIE)과 같은 건식 식각법이 이용될 수 있다.FIG. 5 is a cross-sectional view illustrating an etching step of the present invention. Specifically, FIG. 4 illustrates a process of forming holes by etching between spear particles spaced through an ashing process. In this case, the portion in which the sphere particles 30 are formed is not etched, and the spaced part spaced between the sphere particles and the sphere particles is etched to form holes. The hole may be selectively formed from the metal mask layer 22 to the substrate 10. The etching process may use a dry etching method such as reactive ion etching (RIE) or inductively coupled plasma reactive ion etching (ICP-RIE).
이러한 건식 식각법은 습식 식각법과 달리, 일방성 식각이 가능하여 이러한 패턴을 형성하기에 적합하다. 즉, 습식 식각법은 등방성(isotropic) 식각이 이루어져, 모든 방향으로 식각이 이루어지나, 이와 달리 건식 식각법은 홀을 형성하기 위한 깊이 방향이 주로 식각되는 식각이 가능하여, 홀의 크기 및 간격 등을 원하는 패턴으로 형성할 수 있다.Unlike the wet etching method, the dry etching method is capable of unidirectional etching and is suitable for forming such a pattern. That is, the wet etching method is an isotropic etching, the etching is performed in all directions, but the dry etching method can be etched mainly in the depth direction to form a hole, the size and spacing of the holes, etc. It can be formed in a desired pattern.
이때, 상기 RIE 또는 ICP-RIE법을 이용할 경우, 금속 마스크를 식각할 수 있는 에칭 가스로는 Cl2, O2 등이 이용될 수 있다.In this case, when the RIE or ICP-RIE method is used, Cl 2 , O 2, or the like may be used as an etching gas capable of etching the metal mask.
상기 식각공정을 통해 제조된 LED 소자의 간격(A)은 스피어 입자(30)의 직경과 일치하게 되고, 이 경우 LED 소자의 간격(A)은 나노미터 단위 또는 마이크로미터 단위일 수 있으며, 보다 바람직하게는 50 ~ 3000㎚일 수 있다.The spacing (A) of the LED device manufactured by the etching process is matched with the diameter of the sphere particles 30, in this case, the spacing (A) of the LED device may be in the nanometer unit or micrometer unit, more preferably Preferably from 50 to 3000 nm.
도 6은 식각공정 이후 상기 스피어 입자(30), 금속 마스크층(22) 및 절연층(21)을 제거하는 단계로서, 통상의 습식식각 또는 건식식각 등의 방법을 통해 제거공정을 수행할 수 있다.6 is a step of removing the sphere particles 30, the metal mask layer 22 and the insulating layer 21 after the etching process, the removal process may be performed by a conventional wet etching or dry etching method. .
본 발명의 다른 구현예에 따르면, 상기 2) 단계는; 2-1) 제2 도전성 반도체층의 위에 제2 전극층, 절연층 및 금속 마스크층을 순차적으로 형성하는 단계; 2-2) 상기 금속 마스크층 위에 폴리머층을 형성하고 상기 폴리머층에 나노 또는 마이크로 간격으로 패턴을 형성하는 단계; 2-3) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 패턴에 따라 나노 또는 마이크로 간격으로 건식 또는 습식 식각하는 단계; 및 2-4) 상기 절연층, 금속 마스크층 및 폴리머층을 제거하는 단계를 포함할 수 있다.According to another embodiment of the invention, the step 2) is; 2-1) sequentially forming a second electrode layer, an insulating layer, and a metal mask layer on the second conductive semiconductor layer; 2-2) forming a polymer layer on the metal mask layer and forming a pattern on the polymer layer at nano or micro intervals; 2-3) dry or wet etching the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer at nano or micro intervals according to a pattern; And 2-4) removing the insulating layer, the metal mask layer, and the polymer layer.
구체적으로, 제2 도전성 반도체층의 위에 제2 전극층, 금속 마스크층 및 절연층을 형성한 후, 상기 금속 마스크층 위에 통상의 리소그래피 등에 사용될 수 있는 통상의 폴리머층을 형성하고, 상기 폴리머층에 포토 리소그레피, e-빔 리소그래피, 또는 나노 임프린트 리소그래피 등의 방법을 통해 나노 또는 마이크로 간격으로 패턴을 형성한 후, 이를 건식 또는 습식식각하고 절연층, 금속 마스크층 및 폴리머층을 제거하는 것을 통해 달성될 수 있다.Specifically, after forming the second electrode layer, the metal mask layer and the insulating layer on the second conductive semiconductor layer, a conventional polymer layer that can be used for conventional lithography, etc. is formed on the metal mask layer, and a photo on the polymer layer Achieved by forming patterns at nano or micro intervals through methods such as lithography, e-beam lithography, or nano imprint lithography, followed by dry or wet etching and removal of insulating layers, metal mask layers, and polymer layers Can be.
다음, 3) 단계로서 상기 복수개의 초소형 LED 소자의 외주면에 바인더를 형성하여 하나의 번들(bundle)을 형성함으로써 본 발명에 따른 초소형 LED 소자 번들을 제조할 수 있다.Next, as a step 3), one bundle may be formed by forming a binder on the outer circumferential surface of the plurality of ultra-small LED devices to manufacture the micro-LED bundle according to the present invention.
상기 3) 단계는; 3-1) 제2 전극층의 위에 지지필름을 형성하는 단계; 3-2) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 포함하는 외주면에 절연피막을 형성하는 단계; 3-3) 상기 기판을 제거하는 단계; 3-4) 절연피막이 형성된 상기 복수개의 초소형 LED 소자들의 외주면에 바인더를 형성하여 복수개의 번들(bundle)을 형성하는 단계; 3-5) 상기 제1 도전성 반도체층의 하부에 제1 전극을 형성하는 단계; 3-6) 상기 제1 도전성 반도체층의 하부에 형성된 제1 전극에 자기조립을 위하여 결합링커를 부착하는 단계; 및 3-7) 상기 지지필름을 제거하여 복수개의 초소형 LED 소자 번들을 제조하는 단계를 포함할 수 있다.Step 3); 3-1) forming a supporting film on the second electrode layer; 3-2) forming an insulating film on an outer circumferential surface including the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer; 3-3) removing the substrate; 3-4) forming a plurality of bundles by forming a binder on an outer circumferential surface of the plurality of micro LED devices having an insulating film formed thereon; 3-5) forming a first electrode under the first conductive semiconductor layer; 3-6) attaching a coupling linker for self-assembly to the first electrode formed under the first conductive semiconductor layer; And 3-7) manufacturing the plurality of micro LED bundles by removing the support film.
도 7은 본 발명의 제2 전극층(20) 위에 지지필름(70)을 부착하는 단계를 나타내는 단면도이다. 상기 지지필름(70)은 기판(10)을 레이저 리프트-오프 (laser lift-off: LLO) 방법을 통해 제거할 때 복수개의 초소형 LED 소자가 분산되지 않도록 지지하며, 또한 LED 소자의 크랙을 방지하기 위해 부착하는 것으로서, 상기 지지필름의 재질은 폴리머 엑포시 또는 본딩 메탈일 수 있으며, 두께는 0.3 ~ 70 ㎛일 수 있으나, 이에 제한되지 않는다.7 is a cross-sectional view showing the step of attaching the support film 70 on the second electrode layer 20 of the present invention. The support film 70 supports a plurality of ultra-small LED devices so as not to be dispersed when the substrate 10 is removed through a laser lift-off (LLO) method, and also prevents cracking of the LED devices. In order to attach, the material of the support film may be a polymer exposure or bonding metal, the thickness may be 0.3 ~ 70 ㎛, but is not limited thereto.
도 8은 본 발명의 지지필름이 형성된 초소형 LED 소자들에 대하여 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 포함하는 외주면에 절연피막(80)을 형성한다. 이를 통해 초소형 LED 소자 표면의 결함을 최소화하여 수명과 효율을 향상시키는 효과를 달성할 수 있다.8 illustrates an insulating film 80 formed on an outer circumferential surface including the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer with respect to the micro LED devices having the supporting film of the present invention. This minimizes defects on the surface of tiny LED devices, resulting in improved lifetime and efficiency.
상기 절연피막은 제1 도전성 반도체층(11), 활성층(12) 및 제2 도전성 반도체층(13) 뿐만 아니라, 제1 전극층 및/또는 제2 전극층 및 기타 다른 층의 외주면에도 형성될 수 있다. The insulating film may be formed not only on the first conductive semiconductor layer 11, the active layer 12, and the second conductive semiconductor layer 13, but also on the outer circumferential surface of the first electrode layer and / or the second electrode layer and other layers.
초소형 LED 소자들의 외주면에 절연피막을 형성하는 방법은 상기 지지필름(70) 및 기판(10)이 부착된 초소형 LED 소자들의 외주면에 절연물질을 도포하거나 이를 침지하는 방법을 이용할 수 있으나, 이에 제한되지 않는다. 상기 절연피막으로 사용될 수 있는 물질로는, SiO2, Si3N4, Al2O3 및 TiO2로 이루어지는 군으로부터 선택되는 어느 하나 이상이 사용될 수 있으나, 이에 제한되지 않는다. 예를 들어, Al2O3막은 원자층 증착 (atomic layer deposition: ALD)방식을 통하여 형성할 수 있으며, 트리메틸알루미늄 (trimethyl aluminum: TMA)와 H2O 소스를 펄스형태로 공급하여 화학적 흡착과 탈착을 이용하여 박막을 형성할 수 있다.The method of forming an insulating film on the outer circumferential surface of the micro LED devices may be a method of applying or dipping an insulating material on the outer circumferential surfaces of the micro LED devices to which the support film 70 and the substrate 10 are attached, but are not limited thereto. Do not. As a material that may be used as the insulating film, any one or more selected from the group consisting of SiO 2 , Si 3 N 4 , Al 2 O 3, and TiO 2 may be used, but is not limited thereto. For example, the Al 2 O 3 film can be formed by atomic layer deposition (ALD), and trimethyl aluminum (TMA) and H 2 O sources are supplied in the form of pulses for chemical adsorption and desorption. The thin film can be formed by using.
도 9는 본 발명의 LED 소자들의 제1 도전성 반도체층(11)의 아래에 형성된 기판(10)을 제거하는 단계를 나타내는 단면도이다. 상기 기판(10)을 제거하는 방법은 통상적으로 사용되는 방법을 이용할 수 있으며, 바람직하게는 화학적 리프트-오프 (chemical lift-off: CLO)나 레이저 리프트-오프 (laser lift-off: LLO) 방식을 이용할 수 있으나, 이에 제한되지 않는다.9 is a cross-sectional view showing a step of removing the substrate 10 formed under the first conductive semiconductor layer 11 of the LED elements of the present invention. The method of removing the substrate 10 may be a conventionally used method, preferably chemical lift-off (CLO) or laser lift-off (LLO) method. Can be used, but is not limited thereto.
도 10은 본 발명의 지지필름이 형성된 초소형 LED 소자들의 외주면에 바인더(90, 91)를 형성시킴으로써, 초소형 LED 소자 번들을 제조한 단면도이다. 구체적으로, 도 10에서는 예를 들어, 5개의 초소형 LED 소자의 외주면을 바인더 (90, 91) 처리하여 하나의 초소형 LED 소자 번들을 제조한 것이다. 이 때, 하나의 번들을 형성하는 초소형 LED 소자들의 개수는 5개 이상일 수 있으며, 바람직하게는 취급의 용이성을 위하여 5 ~ 100개를 하나의 번들로 형성할 수도 있다. 사용될 수 있는 바인더는 번들을 형성할 수 있는 것이면 종류의 제한이 없지만 바람직하게는 폴리머 또는 스핀-온-글래스를 사용할 수 있으며, 상기 폴리머로는 SU-8, 폴리(메틸메타크릴레이트) (poly(methylmethacrylate): PMMA), 폴리(4-히드록시스티렌) (poly(4-hydroxystyrene), 폴리(메틸글루타르이미드) (poly(methyl glutarimide): PMGI) 등과 같은 감광성 폴리머를 사용할 수 있으나, 이에 제한되지 않는다. 또한, 번들 간에 응집현상을 방지하기 위하여 상기 바인더는 소수성을 띄거나 소수성 물질이 코팅될 수 있다.10 is a cross-sectional view of manufacturing a micro LED package by forming binders 90 and 91 on the outer circumferential surfaces of the micro LED devices on which the support film of the present invention is formed. Specifically, in FIG. 10, for example, one ultra-small LED device bundle is manufactured by treating the outer circumferential surfaces of five micro-LED devices with binders 90 and 91. At this time, the number of the ultra-small LED elements forming one bundle may be five or more, preferably 5 to 100 in one bundle for ease of handling. The binder that can be used is not limited as long as it can form a bundle, but preferably a polymer or spin-on-glass may be used, and the polymer may be SU-8, poly (methyl methacrylate) (poly ( methylmethacrylate): PMMA), poly (4-hydroxystyrene) (poly (4-hydroxystyrene), poly (methyl glutarimide) (poly (methyl glutarimide): a photosensitive polymer such as PMGI) may be used, but is not limited thereto In addition, the binder may be hydrophobic or coated with a hydrophobic material to prevent aggregation between bundles.
한편, 복수개의 번들을 형성하는 방법은 감광성 폴리머를 사용할 경우에 포토리소그래피 방법을 사용할 수 있다. 먼저, 감광성 폴리머를 기판이 제거된 제1 도전성 반도체층에 스핀코팅한 후, 감광성폴리머 타입에 따라 마스크를 위치시킨 후에 자외선을 쏘게 되면 원하는 부분에만 자유롭게 감광성 폴리머를 남길 수 있다. 감광성 폴리머 타입에는 포지티브 타입과 네가티브 타입이 있으며 타입에 따라 마스크를 위치시켜 원하는 부분에 감광성 폴리머를 제거하거나 남길 수 있으며, 이를 통해 복수개의 LED 소자 번들을 형성할 수 있다. 다른 방법은 감광성 폴리머와 건식식각 방법을 사용해 코팅된 감광성 폴리머에서 남기고자 하는 부분은 마스크로 막고 애싱하여 제거하면 원하는 위치에 복수개의 번들을 형성할 수 있다. 또 다른 방법으로는, 위의 방법과 비슷하게 감광성 폴리머 대신 스핀-온-글래스를 사용하여 기판이 제거된 제1 도전성 반도체층에 코팅한 후, 에칭방법을 통해 원하는 위치에 복수개의 LED 소자 번들을 형성할 수도 있다. 상기 번들 형성방법은 예시적인 것으로서, 이외에도 다양한 방법을 통해 초소형 LED 소자들의 번들을 형성할 수 있다.On the other hand, the method of forming a plurality of bundles can be used a photolithography method when using a photosensitive polymer. First, after the photosensitive polymer is spin-coated to the first conductive semiconductor layer from which the substrate is removed, the mask may be positioned according to the photosensitive polymer type, and then ultraviolet rays may be freely left in only a desired portion. Photosensitive polymer types include a positive type and a negative type, and a mask may be positioned according to the type to remove or leave the photosensitive polymer in a desired portion, thereby forming a plurality of LED device bundles. Another method is to use a photosensitive polymer and a dry etching method to mask a portion of the photosensitive polymer to be left with a mask and ashing to remove a plurality of bundles in the desired position. In another method, similar to the above method, spin-on-glass is used instead of the photosensitive polymer to coat the first conductive semiconductor layer from which the substrate is removed, and then a plurality of LED device bundles are formed at desired positions by etching. You may. The bundle forming method is exemplary, and in addition to this, a bundle of micro LED devices may be formed through various methods.
도 11은 본 발명의 기판(10)이 제거된 제1 도전성 반도체층(11)의 아래에 제1 전극(110)을 형성하는 단계를 나타내는 단면도이다. 상기 제1 전극(110)은 통상적으로 LED 소자에 사용되는 재질이면 제한없이 사용될 수 있으며, 바람직하게는 Cr, Ti, Al, Au, Ni, ITO 및 이들의 산화물 또는 합금 등을 단독 또는 혼합한 재질이 사용될 수 있다. 또한, 전극의 두께는 0.02 ~ 1 ㎛일 수 있으나, 이에 제한되지 않는다.11 is a cross-sectional view illustrating a step of forming the first electrode 110 under the first conductive semiconductor layer 11 from which the substrate 10 of the present invention is removed. The first electrode 110 may be used without limitation as long as it is a material generally used in an LED device. Preferably, the material is a single or mixed material such as Cr, Ti, Al, Au, Ni, ITO and oxides or alloys thereof. This can be used. In addition, the thickness of the electrode may be 0.02 ~ 1 ㎛, but is not limited thereto.
도 12는 본 발명의 제1 전극(110)의 표면에 자기조립을 위한 결합링커(120)를 코팅하는 단계를 나타내는 단면도이다. 상술한 바와 같이, 초소형 LED 소자는 크기가 너무 작기 때문에 이를 LED 디스플레이 기판의 서브픽셀(픽셀자리)에 부착하는 경우, 초소형 LED 소자가 바로서지 못하고 누워있거나 뒤집히는 문제가 발생할 수 있다. 이를 방지하기 위하여 제1 전극(110)의 표면에 자기조립을 위한 결합링커(120)를 코팅하고, 이에 대응하는 LED 디스플레이 기판의 서브픽셀(픽셀자리)에 상기 결합링커(12O)와 결합할 수 있는 제2 링커(미도시)를 형성한다면, 상기 초소형 LED 소자를 전사하거나 잉크 또는 페이스트 형태로 상기 서브픽셀에 부가하는 경우에도 초소형 LED 소자가 누워있거나 뒤집히지 않고 전극표면이 원하는 위치의 서브픽셀에 부착될 수 있는 것이다. 또한 제2 링커를 형성하지 않더라도 결합링커에 남아있는 관능기가 LED 디스플레이 기판의 서브픽셀의 표면에 결합한다면 초소형 LED 소자가 바로서지 못하고 누워있거나 뒤집히는 문제를 해결할 수 있다.12 is a cross-sectional view illustrating a step of coating a coupling linker 120 for self-assembly on the surface of the first electrode 110 of the present invention. As described above, when the ultra-small LED device is so small in size, when it is attached to a subpixel (pixel seat) of the LED display substrate, there may be a problem that the ultra-small LED device does not stand upright and is lying or flipped over. In order to prevent this, the coupling linker 120 for self-assembly may be coated on the surface of the first electrode 110, and the coupling linker 12O may be coupled to a subpixel (pixel position) of the corresponding LED display substrate. If a second linker (not shown) is formed, even when the micro LED element is transferred or added to the sub pixel in the form of ink or paste, the micro LED element does not lie down or flipped, and the electrode surface is positioned on the sub pixel at a desired position. It can be attached. In addition, even if the second linker is not formed, if the functional group remaining in the coupling linker is bonded to the surface of the subpixel of the LED display substrate, the small LED device may not solve the problem of laying down or flipping.
결합링커는 초소형 LED 소자의 전극표면과 디스플레이 기판의 서브픽셀의 표면 및/또는 서브픽셀에 형성된 제2 링커와 결합하여야 하므로, 이를 위하여 2개 이상의 관능기를 가질 수 있다. 구체적으로, 메탈과 반응하는 티올계열의 아미노에테인싸이올 (aminoethanethiol)과 산화물 및 이와 반응하는 아미노프로필트리에톡시실란 (aminopropyltrirthoxysilane) 등이 사용될 수 있으나, 이에 제한되는 것은 아니다. 또한, 디스플레이 기판의 서브픽셀의 표면에 형성되는 제2 링커는 본 발명의 결합링커에 상보적으로 결합할 수 있는 것이면 제한없이 사용될 수 있으며, 바람직하게는 결합링커와 동일한 계열을 사용할 수 있다.The coupling linker must be coupled to the electrode surface of the micro LED device and the surface of the subpixel of the display substrate and / or the second linker formed on the subpixel, and thus may have two or more functional groups. Specifically, a thiol-based aminoethanethiol and an oxide reacting with a metal and an aminopropyltrirthoxysilane reacting with the metal may be used, but are not limited thereto. In addition, the second linker formed on the surface of the subpixel of the display substrate may be used without limitation as long as it can be complementarily bonded to the coupling linker of the present invention. Preferably, the same series as the coupling linker may be used.
도 13은 상기 지지필름(70)을 제거하여 독립된 초소형 LED 소자들(130, 131)을 제조하는 것이다. 한편, 본 발명의 다른 일구현예에 따르면, 상기 결합링커(120)는 지지필름(70)을 제거한 후, 제2 전극(20)과 제1 전극(110) 중 적어도 일면에 형성될 수 있다.FIG. 13 is to manufacture the independent micro LEDs 130 and 131 by removing the support film 70. On the other hand, according to another embodiment of the present invention, the coupling linker 120 may be formed on at least one surface of the second electrode 20 and the first electrode 110 after removing the support film 70.
한편, 본 발명은, 제1 도전성 반도체층; 상기 제1 도전성 반도체층 위에 형성된 활성층; 상기 활성층 위에 형성된 제2 도전성 반도체층을 포함하는 직경이 마이크로 또는 나노 크기의 복수개의 초소형 LED 소자를 포함하며, 상기 복수개의 초소형 LED 소자는 그 외주면에 바인더가 형성되어 하나의 번들(bundle)을 형성하는 초소형 LED 소자 번들을 제공한다.On the other hand, the present invention, the first conductive semiconductor layer; An active layer formed on the first conductive semiconductor layer; A plurality of micro LED devices having a diameter of a micro or nano size including a second conductive semiconductor layer formed on the active layer, the plurality of micro LED devices is a binder formed on the outer peripheral surface to form a bundle Provides a compact LED device bundle.
도 14는 본 발명의 초소형 LED 소자를 나타내는 사시도로서, 본 발명에 따른 초소형 LED 소자는, 제1 도전성 반도체층(140) 위에 형성된 활성층(141), 상기 활성층(141) 위에 형성된 제2 도전성 반도체층(142)를 포함하며, 상기 제1 도전성 반도체층(140)의 아래에는 제1 전극(143)이 형성되고, 상기 제2 도전성 반도체층(142)의 상부에는 제2 전극(144)이 형성될 수 있다. 물론, 상술한 바와 같이 별도의 버퍼층, 활성층, 형광체층 및/또는 반도체층 등을 더 포함되는 것도 가능하다. 한편, 절연피막(150)은 상기 제1 도전성 반도체층(140) 위에 형성된 활성층(141), 상기 활성층(141) 위에 형성된 제2 도전성 반도체층(142)의 일부 또는 전부의 외주면을 포함하여 감싸도록 형성될 수 있다. 또한, 상기 제1 전극(143) 및/또는 제2 전극(144)의 일부 또는 전부의 외주면을 포함하여 감싸도록 형성될 수 있다.FIG. 14 is a perspective view illustrating a micro LED device according to the present invention. The micro LED device according to the present invention includes an active layer 141 formed on the first conductive semiconductor layer 140 and a second conductive semiconductor layer formed on the active layer 141. 142, wherein a first electrode 143 is formed under the first conductive semiconductor layer 140, and a second electrode 144 is formed on the second conductive semiconductor layer 142. Can be. Of course, as described above, a separate buffer layer, an active layer, a phosphor layer, and / or a semiconductor layer may be further included. On the other hand, the insulating film 150 to surround the active layer 141 formed on the first conductive semiconductor layer 140, including the outer peripheral surface of part or all of the second conductive semiconductor layer 142 formed on the active layer 141 Can be formed. In addition, the first and second electrodes 143 and / or the second electrode 144 may be formed to include an outer circumferential surface thereof.
한편, 본 발명의 도면들은 절연피막(80) 및 내부에 형성된 반도체층들을 명확하게 살펴보기 위해서, 상기 절연피막 및/또는 바인더가 반도체층 등을 일부만 감싸도록 도시하고 있으나, 실제로는 외주면 전체를 감쌀 수 있다.Meanwhile, in order to clearly see the insulating film 80 and the semiconductor layers formed therein, the drawings of the present invention show that the insulating film and / or the binder cover only a portion of the semiconductor layer, but actually cover the entire outer circumferential surface thereof. Can be.
도 15는 본 발명의 초소형 LED 소자 번들을 나타내는 사시도로,서 상기 개개의 초소형 LED 소자들은 그 외주면을 바인더(90)가 감싸게 되어 하나의 번들(bundle)이 형성된다. 상술한 바와 같이 하나의 번들을 형성하는 초소형 LED 소자들의 개수는 5개 이상일 수 있다. 또한, 도 15는 초소형 LED 소자의 구조를 도시하기 위하여 바인더(90)의 일부만을 나타낸 것으로서, 실제로는 상기 폴리머 바인더(80)가 초소형 LED 소자들의 외주면을 감싸 하나의 번들을 형성할 수 있다. 또한, 도 15는 바인더(90)의 내부에 절연피막(80)이 형성된 구성을 도시하였지만 이에 한정되는 것은 아니며, 절연피막(80)이 형성되지 않고 바인더(90)가 형성되는 것도 가능하다.FIG. 15 is a perspective view illustrating the ultra-small LED device bundle of the present invention, wherein the individual micro-LED devices bundle a binder 90 around the outer circumferential surface thereof to form a bundle. As described above, the number of micro LEDs forming one bundle may be five or more. In addition, FIG. 15 illustrates only a part of the binder 90 in order to show the structure of the ultra-small LED device. In practice, the polymer binder 80 may form a bundle around the outer circumferential surface of the ultra-small LED devices. In addition, although FIG. 15 illustrates a configuration in which the insulating film 80 is formed inside the binder 90, the present invention is not limited thereto, and the binder 90 may be formed without forming the insulating film 80.
도 16은 본 발명의 전극의 표면에 자기조립을 위한 결합링커가 형성된 초소형 LED 소자를 나타내는 사시도이다. 상술한 바와 같이, 초소형 LED 소자는 크기가 너무 작기 때문에 이를 LED 디스플레이 기판의 서브픽셀(픽셀자리)에 부착하는 경우 초소형 LED 소자가 바로서지 못하고 누워있거나 뒤집히는 문제가 발생할 수 있다. 이를 방지하기 위하여 제1 전극(143) 및 제2 전극(144) 중 적어도 일면에 자기조립을 위한 결합링커(170)가 형성될 수 있다. 구체적으로, 상기 제1 전극(143)의 표면에 결합링커(170)가 형성되고 이에 대응하는 LED 디스플레이 기판의 서브픽셀(픽셀자리)에 상기 결합링커(17O)와 결합할 수 있는 제2 링커(미도시)를 형성한다면, 상기 초소형 LED 소자를 전사하거나 잉크 또는 페이스트 형태로 상기 서브픽셀에 부가하는 경우에도 초소형 LED 소자가 누워있거나 뒤집히지 않고 전극 표면이 원하는 위치의 서브픽셀에 부착될 수 있는 것이다.FIG. 16 is a perspective view of a micro LED device in which a coupling linker for self-assembly is formed on a surface of an electrode of the present invention. FIG. As described above, since the micro LED device is too small in size, when the micro LED device is attached to a subpixel (pixel position) of the LED display substrate, there may be a problem that the micro LED device does not stand upright and is lying or flipped over. In order to prevent this, a coupling linker 170 for self-assembly may be formed on at least one surface of the first electrode 143 and the second electrode 144. Specifically, a second linker (170) is formed on the surface of the first electrode (143) and can be coupled to the coupling linker (17O) in a subpixel (pixel position) of the LED display substrate corresponding thereto. (Not shown), the electrode surface may be attached to the sub-pixel at the desired position without lying or upside down even when the micro-LED element is transferred or added to the sub-pixel in the form of ink or paste. .
나아가, 제1 전극(143)과 제2 전극(144)에 모두 결합링커(170)가 형성된다면, LED 디스플레이 기판의 서브픽셀(픽셀자리)에 결합되는 초소형 LED 소자의 일부는 상기 제1 전극(143)이 결합되고 나머지는 제2 전극(144)이 결합될 것이다. 이 경우, LED 디스플레이 기판에 교류를 인가하면 LED 디스플레이를 구동할 수 있게 된다.Furthermore, if the coupling linker 170 is formed on both the first electrode 143 and the second electrode 144, a part of the ultra-small LED device coupled to the subpixel (pixel position) of the LED display substrate may be the first electrode ( 143 is coupled and the second electrode 144 is coupled. In this case, when an alternating current is applied to the LED display substrate, the LED display can be driven.
본 발명의 초소형 LED 소자의 형상은 원통형, 직육면체형 등 제한없이 형성될 수 있으나, 바람직하게는 원통형일 수 있으며, 원통형인 경우 직경(원의 직경)은 50 ~ 3000㎚일 수 있으며, 높이(제1전극에서 제2 전극까지의 길이)는 1.5 ~7㎛일 수 있으나, 이에 제한되지 않는다.The shape of the ultra-small LED device of the present invention may be formed without limitation, such as cylindrical, rectangular parallelepiped, preferably cylindrical, in the case of a cylindrical diameter (circle diameter) may be 50 ~ 3000nm, height (second Length from one electrode to the second electrode) may be 1.5 ~ 7㎛, but is not limited thereto.
도 17은 본 발명의 초소형 LED 소자 번들을 포함하는 잉크 또는 페이스트로서, 본 발명의 초소형 LED 소자 번들은 디스플레이 기판의 서브픽셀에 직접 전사되거나 잉크 또는 페이스트의 형태로 전사될 수 있다.17 is an ink or paste comprising the micro LED bundle of the present invention, the micro LED bundle of the present invention can be transferred directly to a subpixel of the display substrate or in the form of an ink or paste.
이하, 실시예를 통하여 본 발명을 더욱 상세하게 설명하기로 하되, 하기 실시예는 본 발명의 이해를 돕기 위한 것일 뿐, 본 발명의 범위를 제한하는 것은 아니다.Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are only intended to help the understanding of the present invention, but are not intended to limit the scope of the present invention.
LED 기본 소자층 (GaN)을 제조하기 위해서 사파이어 기판 (2인치 웨이퍼 사이즈, 430±25㎛) 위에 버퍼층 또는 언도프드 반도체층 (undoped GaN, 2.4~2.8㎛ 두께), 제1 도전성 반도체층 (n-타입 GaN, 2.0~2.4㎛ 두께), 활성층 (InGaN/GaN 다중 양자 우물, 100~140㎛), 제2 도전성 반도체층 (p-타입 GaN, 200nm 두께)을 MOCVD 방법을 이용하여 형성하였다 (도 18 참조). Buffered or undoped semiconductor layer (undoped GaN, 2.4-2.8 μm thick), first conductive semiconductor layer (n−) on a sapphire substrate (2 inch wafer size, 430 ± 25 μm) to manufacture an LED basic device layer (GaN) Type GaN, 2.0-2.4 μm thick), active layer (InGaN / GaN multi-quantum well, 100-140 μm), and second conductive semiconductor layer (p-type GaN, 200 nm thick) were formed using MOCVD method (FIG. 18). Reference).
위와 같이 제조된 LED 기본 소자층을 하기와 같은 방법에 의해서 초소형 LED 소자로 제조하였다. 먼저, 제2 도전성 반도체층 위에 절연층으로서 SiO2 (800nm~1㎛ 두께)와 금속 마스크층으로서 크롬층 (100~120nm 두께)을 각각 PECVD 방법과 열증착 (thermal evaporation) 방법으로 형성하였다 (PECVD: 60W, 550mtorr, SiH4 160sccm, N2 240sccm, N2O 1500sccm, 35~40분; 열증착: 130~140A, 9.0x10-6torr, 20~30분) (도 19 참조). 이어서, 폴리스티렌 나노스피어를 헥사고날 형태로 잘 정렬된 단층막 (960~1000nm 두께)으로 제조하여 상기 금속 마스크층 위에 형성하였다 (도 20a 및 20b 참조). 상기 단층막을 O2 가스 분위기하에서 애싱공정 (50W, 0.05torr, O2 100sccm)을 통해 500~800nm의 크기로 줄여 주었다 (도 21a 및 21b 참조). 크기가 축소된 폴리스티렌 나노스피어를 마스크로 사용하여, 상기 금속 마스크층을 건식 식각 방법인 RIE 방법으로 Cl2 가스 분위기하에서 에칭하였다 (50W, 0.08torr, Cl2 40sccm) (도 22a 및 22b 참조). 상기 에칭공정에 의해서 폴리스티렌의 모양 그대로 전사(transfer)된 금속 마스크층 패턴을 제조하였으며 (도 23a 및 23b 참조), 제조된 금속 마스크층 패턴을 이용해서 하부에 존재하는 절연층 부분을 CF4와 O2 가스 분위기 하에서 다시 에칭하였다 (100W, 0.042torr, CF4 40sccm, O2 2sccm) (도 24a 및 24b 참조). 라드패턴으로 식각된 절연층을 이용하여 반도체층 (GaN)을 SiCl4와 Ar 가스 분위기 하에서 ICP 방법으로 에칭하여 (RF 50W, ICP 300W, 3 torr, SiCl4 2sccm, Ar 20sccm), 반도체층의 라드패턴을 제조하였다 (도 25a 및 25b 참조). 이어서, 반도체층 라드패턴을 제조하기 위해서 마스크로 사용되었던 절연층을 CF4와 O2 가스 분위기 하에서 에칭하여 제거하였다 (도 26a 및 26b 참조).The LED basic device layer manufactured as described above was manufactured as a micro LED device by the following method. First, SiO 2 (800 nm to 1 μm thick) as an insulating layer and a chromium layer (100 to 120 nm thick) as a metal mask layer were formed on the second conductive semiconductor layer by PECVD and thermal evaporation, respectively (PECVD). : 60W, 550mtorr, SiH 4 160sccm , N 2 240sccm, N 2 O 1500sccm, 35 ~ 40 minutes; thermal deposition: 130 ~ 140A, 9.0x10 -6 torr , 20 ~ 30 minutes) (see FIG. 19). Subsequently, polystyrene nanospheres were prepared as monolayer films (960-1000 nm thick) well aligned in hexagonal form and formed on the metal mask layer (see FIGS. 20A and 20B). The monolayer film was reduced to a size of 500-800 nm through an ashing process (50W, 0.05torr, O 2 100sccm) in an O 2 gas atmosphere (see FIGS. 21A and 21B). Using the reduced size polystyrene nanospheres as a mask, the metal mask layer was etched under Cl 2 gas atmosphere by RIE method (dry etching method) (50W, 0.08torr, Cl 2 40sccm) (see FIGS. 22A and 22B). An insulating layer portion wherein the same transfer form of polystyrene by the etching process (transfer) was prepared in the metal mask layer pattern (see Fig. 23a and 23b), by using the prepared metal mask layer pattern is present on the lower CF 4 and O Etched again under 2 gas atmosphere (100W, 0.042torr, CF 4 40sccm, O 2 2sccm) (see FIGS. 24A and 24B). The semiconductor layer (GaN) was etched by ICP method under SiCl 4 and Ar gas atmosphere using the insulating layer etched by the rod pattern (RF 50W, ICP 300W, 3 torr, SiCl 4 2sccm, Ar 20sccm) The pattern was prepared (see FIGS. 25A and 25B). Subsequently, the insulating layer, which was used as a mask to manufacture the semiconductor layer rod pattern, was removed by etching under a CF 4 and O 2 gas atmosphere (see FIGS. 26A and 26B).
상기와 같이 제조된 반도체층의 외주면에 원자층 증착 (atomic layer deposition: ALD) 방법 (금속 반응물질로서 트리메틸알루미늄 (trimethylaluminum: TMA)를, 산소 소스로서 수증기를 사용하고, TMA 증기압은 0.04 torr로, 챔버 온도는 80℃로 유지, 캐리어 가스 및 퍼징 가스로는 Ar을 사용, 성장 속도: ~1.5Å)에 의해서 절연피막(Al2O3)을 코팅하였으며 (두께: 20nm), 액상의 자기조립공정을 통하여 소수성 피막으로서, 옥타데실트리클로로실란 (octadecyltrichlorosilane: OTS)을 수 nm의 두께로 코팅하였다. 도 27a 및 27b를 참조하면, 이러한 소수성 피막 코팅에 의해서 물과의 접촉각이 증가함을 알 수 있다. 절연피막과 소수성 피막을 코팅한 후, 제2 전극층 위에 에폭시 수지 (시아노아크릴레이트 접착제 금속-타입, Sigma Aldrich사로부터 구입)를 이용하여 지지필름을 부착하였다 (두께: 3.5~5㎛). 이어서, 지지필름이 부착되어 있지 않은 버퍼층 또는 언도프드 반도체층과 사파이어 기판 쪽으로 레이저를 이용한 리프트-오프 공정을 수행함으로써 사파이어 기판을 제거하였다 (도 28a 및 28b 참조). 제1 도전성 반도체층이 노출되도록 하기 위해서, 버퍼층 또는 언도프드 반도체층을 SiCl4와 Ar 가스 분위기 하에서 ICP 방법으로 식각하여 제거하였으며 (RF 50W, ICP 300W, 3 torr, SiCl4 2sccm, Ar 20sccm), 이러한 과정을 통해서 지지필름이 부착된 독립적인 초소형 LED 라드형태를 얻을 수 있었다 (도 29a 및 29b, 도 30a 및 30b, 도 31a 및 31b 참조).Atomic layer deposition (ALD) method (trimethylaluminum (TMA) as metal reactant, water vapor as oxygen source, TMA vapor pressure of 0.04 torr) The chamber temperature was maintained at 80 ° C, and Ar was used as the carrier gas and the purging gas, and an insulating film (Al 2 O 3 ) was coated (thickness: 20 nm) by the growth rate: ~ 1.5 kPa). As a hydrophobic coating, octadecyltrichlorosilane (OTS) was coated to a thickness of several nm. Referring to Figure 27a and 27b, it can be seen that the contact angle with water is increased by this hydrophobic coating coating. After coating the insulating film and the hydrophobic film, a supporting film was attached on the second electrode layer by using an epoxy resin (cyanoacrylate adhesive metal-type, purchased from Sigma Aldrich) (thickness: 3.5-5 μm). Subsequently, the sapphire substrate was removed by performing a lift-off process using a laser toward the buffer layer or the undoped semiconductor layer and the sapphire substrate to which the support film was not attached (see FIGS. 28A and 28B). In order to expose the first conductive semiconductor layer, the buffer layer or the undoped semiconductor layer was removed by etching by the ICP method under SiCl 4 and Ar gas atmosphere (RF 50W, ICP 300W, 3 torr, SiCl 4 2sccm, Ar 20sccm), Through this process, it was possible to obtain an independent ultra-small LED rod form to which the support film was attached (see FIGS. 29A and 29B, FIGS. 30A and 30B, and FIGS. 31A and 31B).
초소형 LED 라드형태의 소자들을 번들형으로 제조하기 위해서, 초소형 LED 소자들이 지지필름에서 노출되도록 지지필름을 O2 가스 분위기하에서 애싱 공정을 통하여 어느 정도 제거하였다 power 50W, working pressure 0.05torr, O2 100sccm). 이어서, 상기 초소형 LED 소자들을 번들형으로 만들어 줄 바인더 (PMMA, 1.5~2.0㎛ 두께)를 LED 소자에 코팅하였다 (도 32 참조). 바인더 코팅 후, 전극을 제1 도전성 반도체층 위에 형성시키기 위해서, 반도체층이 드러날 때까지 바인더를 O2 가스 분위기 하에서 애싱하여 제거한 뒤 (power 50W, working pressure 0.05torr, O2 100sccm), 전극 (Ti)을 증착하였다 (300V, 0.17A, Ar 100sccm) (도 33 참조). 다음으로, 전극 표면에 결합링커로서 노네인디티올 (nonanedithiol)을 액상 또는 기상의 자기조립방법으로 코팅하였다. 코팅 공정은 액상으로 진행되었으며, 에탈올 무수물 (10ml)와 노네인디티올 (20㎕)을 혼합하여 1mM 노네인디티올 용액을 제조하고, 전극이 증착되어 있는 초소형 LED 라드형태를 상기 노네인디티올 용액에 하루 동안 담근 다음, 초소형 LED 라드를 꺼내어 세척하였다. 상기 지지필름은 아세톤을 이용해 제거함으로써 번들형의 초소형 LED 소자들을 잉크 또는 페이스트 형태로 제조하였다 (도 34a 및 34b 참조). 상기 잉크 또는 페이스트를 그 결합링커 (노네인디티올 링커)와 반응하는 링커 (금속 미분말: 은 나노입자)를 가지고 있는 전극 기판에 떨어뜨림으로써 정렬시켰다. 전극 기판의 경우, 전극 기판과 반응하는 디티올 링커와 초소형 LED의 결합링커와 반응할 수 있는 금속미분말인 은 나노입자를 이용해서 전극 위에 패턴함으로써 패턴을 형성하였다. 구체적으로, 노네인디티올 링커를 먼저 전극 기판에 반응시켜 붙인 후, 전극 기판과 붙어있지 않은 노네인디티올 링커 반대쪽으로 은 나노입자를 코팅하였다. 코팅은 노네인디티올 링커가 붙어 있는 전극 기판을 은 나노입자가 분산되어 있는 톨루엔 용액에 넣어 반응시킨 후 꺼냄으로써 수행하였다. 이러한 과정에 의해서 전극 기판의 금속 미분말과 초소형 LED 소자 번들의 결합링커를 반응시킨 다음, 솔더링 공정 (100~200℃의 어닐링 과정)을 통하여 금속 오믹층을 형성함으로써 본 발명에 따른 초소형 LED 소자 번들을 제조하였다 (도 35 참조). 한편, 도 36에는 전술한 바와 같이 제조된 초소형 LED 소자들을 전극 기판에 정렬시킨 후 측정한 스펙트럼을 도시하였으며, 또한 도 37a 내지 37c에는 제조된 초소형 LED 소자에 대한 육안으로 관찰한 사진을 도시하였다. 상기 도면들로부터 알 수 있는 바와 같이, 본 발명에 따른 초소형 LED 소자 번들에서 청색광이 발광되는 것을 확인할 수 있다.In order to bundle the small LED rod-type devices, the supporting film was removed to some extent through an ashing process under an O 2 gas atmosphere so that the small LED devices were exposed from the supporting film. Power 50W, working pressure 0.05torr, O 2 100sccm ). Subsequently, a binder (PMMA, 1.5-2.0 μm thick) to bundle the ultra-small LED devices was coated on the LED devices (see FIG. 32). After the binder coating, in order to form the electrode on the first conductive semiconductor layer, the binder is ashed and removed in an O 2 gas atmosphere until the semiconductor layer is exposed (power 50W, working pressure 0.05torr, O 2 100sccm), and the electrode (Ti ) Was deposited (300V, 0.17A, Ar 100sccm) (see FIG. 33). Next, nonaneedithiol was coated on the surface of the electrode as a bonding linker by liquid or gas phase self-assembly. The coating process was performed in the liquid phase, 1mM nonanedithiol solution was prepared by mixing ethanol anhydride (10ml) and nonanedithiol (20μl), and the ultra-small LED rod form on which the electrode was deposited was added to the nonanedithiol solution. After soaking for one day, the micro LED rod was taken out and washed. The support film was removed using acetone to prepare bundled ultra-small LED devices in the form of ink or paste (see FIGS. 34A and 34B). The ink or paste was aligned by dropping onto an electrode substrate having a linker (metal fine powder: silver nanoparticles) that reacted with its binding linker (nonanedithiol linker). In the case of the electrode substrate, a pattern was formed by patterning on the electrode using silver nanoparticles, which are fine metal powders that can react with the dithiol linker reacting with the electrode substrate and the coupling linker of the micro LED. Specifically, the nonanedithiol linker was first reacted with the electrode substrate, and then coated with silver nanoparticles on the opposite side of the nonanedithiol linker, which is not attached to the electrode substrate. The coating was carried out by taking an electrode substrate having a nonanedithiol linker in a toluene solution in which silver nanoparticles were dispersed, and then removing the electrode substrate. By reacting the fine metal powder of the electrode substrate and the coupling linker of the ultra-small LED device bundle by such a process, the ultra-small LED device bundle according to the present invention is formed by forming a metal ohmic layer through a soldering process (annealing process of 100 ~ 200 ℃) Prepared (see Figure 35). Meanwhile, FIG. 36 illustrates a spectrum measured after aligning the ultra-small LED devices manufactured as described above to an electrode substrate, and also visually observed photographs of the micro LED devices manufactured in FIGS. 37A to 37C. As can be seen from the drawings, it can be seen that the blue light is emitted from the ultra-small LED device bundle according to the present invention.
본 발명에 따른 초소형 LED 소자는 디스플레이 산업 전반에 걸쳐서 폭넓게 활용될 수 있다.The micro LED device according to the present invention can be widely used throughout the display industry.

Claims (15)

1) 기판 위에 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 순차적으로 형성하는 단계;1) sequentially forming a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer on the substrate;
2) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 포함하는 LED 소자의 직경이 나노 또는 마이크로 크기를 가지도록 식각함으로써, 복수개의 초소형 LED 소자를 형성하는 단계; 및2) forming a plurality of ultra-small LED devices by etching the diameter of the LED device including the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer to have a nano or micro size; And
3) 상기 복수개의 초소형 LED 소자의 외주면에 바인더를 형성함으로써, 복수개의 번들(bundle)을 형성하는 단계를 포함하는 초소형 LED 소자 번들의 제조방법.And 3) forming a plurality of bundles by forming a binder on an outer circumferential surface of the plurality of micro LEDs.
제1항에 있어서, 상기 제1 도전성 반도체층은 적어도 하나의 n형 반도체층을 포함하고, 상기 제2 도전성 반도체층은 적어도 하나의 p형 반도체층을 포함하는 것을 특징으로 하는 초소형 LED 소자 번들의 제조방법.The bundle of micro LEDs of claim 1, wherein the first conductive semiconductor layer comprises at least one n-type semiconductor layer and the second conductive semiconductor layer comprises at least one p-type semiconductor layer. Manufacturing method.
제1항에 있어서, 상기 2) 단계는;The method of claim 1, wherein step 2);
2-1) 제2 도전성 반도체층의 위에 제2 전극층, 절연층 및 금속 마스크층을 순차적으로 형성하는 단계;2-1) sequentially forming a second electrode layer, an insulating layer, and a metal mask layer on the second conductive semiconductor layer;
2-2) 상기 금속 마스크층 위에 폴리머층을 형성하고 상기 폴리머층에 나노 또는 마이크로 간격으로 패턴을 형성하는 단계;2-2) forming a polymer layer on the metal mask layer and forming a pattern on the polymer layer at nano or micro intervals;
2-3) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 패턴에 따라 나노 또는 마이크로 간격으로 건식 또는 습식 식각하는 단계; 및2-3) dry or wet etching the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer at nano or micro intervals according to a pattern; And
2-4) 상기 절연층, 금속 마스크층 및 폴리머층을 제거하는 단계를 포함하는 것을 특징으로 하는 초소형 LED 소자 번들의 제조방법.2-4) The method of manufacturing the ultra-small LED device bundle comprising the step of removing the insulating layer, the metal mask layer and the polymer layer.
제1항에 있어서, 상기 2) 단계는;The method of claim 1, wherein step 2);
2-5) 제2 도전성 반도체층의 위에 제2 전극층, 절연층 및 금속 마스크층을 형성하는 단계;2-5) forming a second electrode layer, an insulating layer, and a metal mask layer on the second conductive semiconductor layer;
2-6) 상기 금속 마스크층 위에 나노스피어 또는 마이크로스피어 단층막을 형성하고 자기조립을 수행하는 단계;2-6) forming a nanosphere or microsphere monolayer on the metal mask layer and performing self-assembly;
2-7) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 패턴에 따라 나노 또는 마이크로 간격으로 건식 또는 습식 식각하는 단계; 및2-7) dry or wet etching the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer at nano or micro intervals according to a pattern; And
2-8) 상기 절연층, 금속 마스크층 및 단층막을 제거하는 단계를 포함하는 것을 특징으로 하는 초소형 LED 소자 번들의 제조방법.2-8) A method of manufacturing a small LED device bundle comprising the step of removing the insulating layer, the metal mask layer and the single layer film.
제4항에 있어서, 상기 나노스피어 또는 마이크로스피어는 폴리스티렌 재질인 것을 특징으로 하는 초소형 LED 소자 번들의 제조방법.The method of claim 4, wherein the nanospheres or microspheres are made of polystyrene.
제3항 또는 제4항에 있어서, 상기 3) 단계는;The method of claim 3 or 4, wherein 3) comprises:
3-1) 제2 전극층의 위에 지지필름을 형성하는 단계;3-1) forming a supporting film on the second electrode layer;
3-2) 상기 제1 도전성 반도체층, 활성층 및 제2 도전성 반도체층을 포함하는 외주면에 절연피막을 형성하는 단계;3-2) forming an insulating film on an outer circumferential surface including the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer;
3-3) 상기 기판을 제거하는 단계;3-3) removing the substrate;
3-4) 절연피막이 형성된 상기 복수개의 초소형 LED 소자들의 외주면에 바인더를 형성하여 복수개의 번들(bundle)을 형성하는 단계;3-4) forming a plurality of bundles by forming a binder on an outer circumferential surface of the plurality of ultra-small LED elements having an insulating film formed thereon;
3-5) 상기 제1 도전성 반도체층의 하부에 제1 전극을 형성하는 단계;3-5) forming a first electrode under the first conductive semiconductor layer;
3-6) 상기 제1 도전성 반도체층의 하부에 형성된 제1 전극에 자기조립을 위하여 결합링커를 부착하는 단계; 및3-6) attaching a coupling linker for self-assembly to the first electrode formed under the first conductive semiconductor layer; And
3-7) 상기 지지필름을 제거하여 복수개의 초소형 LED 소자 번들을 제조하는 단계를 포함하는 것을 특징으로 하는 초소형 LED 소자 번들의 제조방법.3-7) Method of manufacturing a small LED device bundle comprising the step of removing the supporting film to produce a plurality of ultra-small LED device bundle.
제1항에 있어서, 상기 바인더는 소수성이며, 상기 복수개의 번들 중 하나의 번들은 5 ~ 100 개의 초소형 LED 소자를 포함하는 것을 특징으로 하는 초소형 LED 소자 번들의 제조방법.The method of claim 1, wherein the binder is hydrophobic, and one bundle of the plurality of bundles includes 5 to 100 ultra-small LED elements.
제1 도전성 반도체층;A first conductive semiconductor layer;
상기 제1 도전성 반도체층 위에 형성된 활성층;An active layer formed on the first conductive semiconductor layer;
상기 활성층 위에 형성된 제2 도전성 반도체층을 포함하는 직경이 마이크로 또는 나노 크기의 복수개의 초소형 LED 소자를 포함하며,A plurality of micro LED devices having a diameter of a micro or nano size including a second conductive semiconductor layer formed on the active layer,
상기 복수개의 초소형 LED 소자는 그 외주면에 바인더가 형성되어 하나의 번들(bundle)을 형성하는 초소형 LED 소자 번들.The plurality of ultra-small LED device is a bundle of ultra-small LED device to form a bundle by forming a binder on the outer peripheral surface.
제8항에 있어서, 상기 바인더는 소수성이며, 하나의 번들은 5 ~ 100개의 초소형 LED 소자를 포함하는 것을 특징으로 하는 초소형 LED 소자 번들.The ultra-small LED device bundle of claim 8, wherein the binder is hydrophobic and one bundle includes 5 to 100 ultra-small LED devices.
제8항에 있어서, 상기 제1 도전성 반도체층의 하부에는 제1 전극층이 형성되고, 상기 제2 도전성 반도체층의 상부에는 제2 전극층이 형성되는 것을 특징으로 하는 초소형 LED 소자 번들.The ultra-small LED device bundle of claim 8, wherein a first electrode layer is formed below the first conductive semiconductor layer, and a second electrode layer is formed above the second conductive semiconductor layer.
제8항에 있어서, 상기 초소형 LED 소자는 바인더의 내부에 형성된 절연피막을 포함하는 것을 특징으로 하는 초소형 LED 소자 번들.The ultra-small LED device bundle of claim 8, wherein the micro-LED device includes an insulating film formed inside the binder.
제10항에 있어서, 상기 제1전극층의 하부면 및 제2 전극층의 상부면 중 적어도 하나의 전극층의 표면에 결합링커를 포함하는 것을 특징으로 하는 초소형 LED 소자 번들.11. The micro LED bundle of claim 10, further comprising a coupling linker on a surface of at least one of the lower surface of the first electrode layer and the upper surface of the second electrode layer.
제12항에 있어서, 상기 결합링커는 LED 디스플레이의 기판과 상보적으로 결합할 수 있는 것을 특징으로 하는 초소형 LED 소자 번들.13. The ultra-small LED device bundle of claim 12, wherein the coupling linker is capable of complementarily coupling with a substrate of the LED display.
제8항에 있어서, 상기 제1 도전성 반도체층은 적어도 하나의 n형 반도체층을 포함하고, 상기 제2 도전성 반도체층은 적어도 하나의 p형 반도체층을 포함하는 것을 특징으로 하는 초소형 LED 소자 번들.The ultra-small LED device bundle of claim 8, wherein the first conductive semiconductor layer comprises at least one n-type semiconductor layer, and the second conductive semiconductor layer comprises at least one p-type semiconductor layer.
제8항에 있어서, 상기 바인더는 감광성 폴리머 및 스핀-온-글래스 (Spin-on-glass)로 이루어지는 군으로부터 선택된 하나 이상의 물질을 포함하는 것을 특징으로 하는 초소형 LED 소자 번들.The ultra-small LED device bundle of claim 8, wherein the binder comprises at least one material selected from the group consisting of a photosensitive polymer and spin-on-glass.
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