LED assembly with improved electrical contact and method for manufacturing same

Abstract

Disclosed are an LED assembly with improved electrical contact by etching both ends of an LED element to increase a contact area between the LED element and a transparent electrode, and a method for manufacturing same. The LED assembly according to the present invention comprises: a substrate; a first electrode and a second electrode spaced apart from each other on the substrate; a first insulating layer covering the first electrode and the second electrode and including a groove in a region between the first electrode and the second electrode; an LED element arranged in the groove and having both ends etched; a second insulating layer disposed in an upper portion of the LED element having both ends etched; and a first transparent electrode and a second transparent electrode spaced apart from each other to surround both ends of the LED element and the second insulating layer.

Description

LED assembly with improved electrical contact and method of manufacturing the same

[0001] The present invention relates to an LED assembly with improved electrical contact by increasing the contact area between an LED element and a transparent electrode by etching both ends of the LED element, and a method for manufacturing the same.

[0002] The research task information of the present invention is as follows.

[0003] Project No.: 00420281, Ministry: Ministry of Trade, Industry and Energy, Specialized Agency: Korea Institute of Industrial Technology Planning and Evaluation, Research Project Name: Technology Development for the Electronic Components Industry, Research Task Title: Development of Single-Cluster Type 6-Inch Class MOCVD Equipment Technology for High-Temperature Nitride Growth for High-Uniformity (Wavelength Uniformity ≤ ±2 nm) LED Characteristics, Performing Agency: Advanced Vue Technology, Research Period: 2024.04.01 ~ 2026.12.31

[0004] An LED device is a semiconductor device that utilizes the properties of compound semiconductors to have a structure in which an n-type semiconductor crystal, in which the majority of carriers are electrons, and a p-type semiconductor crystal, in which the majority of carriers are holes, are joined together.

[0005] LED elements convert electrical signals into light with a desired wavelength range and display it.

[0006] Recently, high-brightness red, orange, green, blue, and white LEDs are being utilized in many fields, including traffic lights, mobile phones, automotive headlights, outdoor electronic displays, LCD BLUs (backlight units), and indoor and outdoor lighting, and active research is continuing both domestically and internationally.

[0007] Meanwhile, in order to utilize LED elements for lighting, displays, etc., an LED element and an electrode capable of supplying power to the element are required. Various studies are being conducted on the arrangement structure of the LED element and two different electrodes in relation to the purpose of use, reduction of the space occupied by the electrode, and manufacturing methods.

[0008] For example, while it is possible to secure a contact area between the contact electrode and the LED element by using a method in which the contact electrode covers the LED element, there are limitations to reducing electrical resistance.

[0009] Therefore, there is a need for research on LED assemblies that can reduce electrical resistance by increasing the contact area between the LED element and the contact electrode.

[0010] The objective of the present invention is to provide an LED assembly with improved electrical contact by increasing the contact area between the LED element and the transparent electrode.

[0011] In addition, the objective of the present invention is to provide an LED assembly that is free from defects and failures and has excellent luminous efficiency.

[0012] In addition, the objective of the present invention is to provide a method for manufacturing an LED assembly capable of increasing the contact area between an LED element and a transparent electrode.

[0013] The objects of the present invention are not limited to those mentioned above, and other unmentioned objects and advantages of the present invention may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0014] An LED assembly according to the present invention comprises: a substrate; a first electrode and a second electrode spaced apart from each other on the substrate; a first insulating layer covering the first electrode and the second electrode, and including a groove in the region between the first electrode and the second electrode; an LED element aligned with the groove and having both ends etched; a second insulating layer disposed on top of the LED element with both ends etched; and a first transparent electrode and a second transparent electrode spaced apart from each other to surround both ends of the LED element and the second insulating layer.

[0015] The length of the groove may be greater than the length of the LED element, and the width of the groove may be greater than the diameter of the LED element. Additionally, the length of the groove may be greater than the distance between the first electrode and the second electrode.

[0016] The above LED element may include an n-type semiconductor layer, an active layer disposed on one side of the n-type semiconductor layer, a p-type semiconductor layer disposed on one side of the active layer, a current dispersing layer disposed on one side of the p-type semiconductor layer, and a passivation layer covering the outer surface of the LED element.

[0017] At this time, the side of the current distribution layer and the side of the n-type semiconductor layer of the LED element can be etched.

[0018] The second insulating layer may include a silicate polymer.

[0019] The above second insulating layer may be further disposed between both ends of the LED element and the side of the groove.

[0020] One LED element can be aligned in the above-mentioned single groove.

[0021] The first transparent electrode can be connected to the source electrode or drain electrode of a transistor disposed on the substrate, and the second transparent electrode is connected to a power supply voltage line (V DD It can be connected to the base voltage line (Vss) or the base voltage line.

[0022] A method for manufacturing an LED assembly according to the present invention comprises: (a) a first electrode and a second electrode spaced apart from each other on a substrate, a first insulating layer covering the first electrode and the second electrode and including a groove in the region between the first electrode and the second electrode, and aligning an LED element in the groove; (b) a second insulating layer formed by depositing a composition for the second insulating layer to cover the LED element; (c) a step of etching the second insulating layer to expose a portion of the outer surface of the LED element and both ends; (d) a step of etching both ends of the LED element; and (e) a step of forming a first transparent electrode and a second transparent electrode spaced apart from each other to surround both ends of the LED element and the second insulating layer.

[0023] In step (a) above, the length of the groove may be greater than the length of the LED element, and the width of the groove may be greater than the diameter of the LED element.

[0024] In step (a) above, the length of the groove may be greater than the distance between the first electrode and the second electrode.

[0025] In step (b) above, the composition for the second insulating layer may include a silicate polymer, an organic solvent, and distilled water.

[0026] Step (c) above may etch the second insulating layer so that the second insulating layer remains in the center of the inner region of the home and the outer surface of the LED element.

[0027] In step (d) above, the LED device can etch the side of the current distribution layer disposed on one side of the p-type semiconductor layer and the side of the n-type semiconductor layer.

[0028] In the above step (e), the method may include: (e1) a step of depositing a transparent electrode to surround both ends of the LED element and the second insulating layer; (e2) a step of patterning a photoresist on the transparent electrode to form a first transparent electrode and a second transparent electrode spaced apart; and (e3) a step of removing the photoresist.

[0029] The LED assembly and the method for manufacturing the same according to the present invention have the effect of improving electrical contact and providing excellent luminous efficiency by etching both ends of the LED element, thereby increasing the contact area between the LED element and the transparent electrode.

[0030] In addition, by depositing a second insulating layer on the outer surface of the LED element during the LED assembly manufacturing process to fix the LED element, there is an effect of preventing defects and failures.

[0031] In addition to the effects described above, the specific effects of the present invention are described together with the specific details for implementing the invention below.

[0032] FIG. 1 is a cross-sectional view of an LED assembly according to the present invention.

[0033] FIG. 2 is a cross-sectional view of LED elements aligned according to the present invention.

[0034] FIG. 3 is a cross-sectional view of an LED element according to the present invention.

[0035] FIG. 4 is a flowchart of a method for manufacturing an LED assembly according to the present invention.

[0036] FIG. 5 is a schematic diagram showing the manufacturing steps of an LED assembly according to the present invention.

[0037] [Explanation of the symbol]

[0038] 10 : Substrate

[0039] 20 : First electrode

[0040] 30 : Second electrode

[0041] 40 : First insulating layer

[0042] 50 : LED element

[0043] 60 : Second insulation layer

[0044] 70 : First transparent electrode

[0045] 80 : Second transparent electrode

[0046] The aforementioned objectives, features, and advantages are described in detail below with reference to the attached drawings, thereby enabling those skilled in the art to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0047] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0048] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0049] Hereinafter, an LED assembly with improved electrical contact and a method for manufacturing the same according to some embodiments of the present invention will be described.

[0050] FIG. 1 is a cross-sectional view of an LED assembly according to the present invention.

[0051] As illustrated in FIG. 1, an LED assembly according to the present invention may include a substrate, a first electrode and a second electrode spaced apart from each other on the substrate, a first insulating layer covering the first electrode and the second electrode and including a groove in the region between the first electrode and the second electrode, an LED element aligned with the groove and having both ends etched, a second insulating layer disposed on top of the LED element with both ends etched, and a first transparent electrode and a second transparent electrode spaced apart from each other to surround both ends of the LED element and the second insulating layer.

[0052] substrate (10)

[0053] The substrate can be an active matrix backplane.

[0054] First electrode (20) and second electrode (30)

[0055] Each of the first electrode and the second electrode may include a commonly used metal or metal oxide, and may include, for example, one or more of Al, Ti, In, Cr, Au, Ni, and ITO.

[0056] When a voltage is applied to the first electrode and the second electrode that are spaced apart from each other, an electric field can be generated between the first electrode and the second electrode, and an attractive force is generated between the first electrode and the second electrode.

[0057] By means of the above force, one end of the LED element located in the groove is superimposed on the first electrode and the other end of the LED element is superimposed on the second electrode, so that the LED element can be aligned in a more solid state in the groove.

[0058] The thickness of the first electrode and the second electrode may be 10 nm to 100 nm, but is not limited thereto.

[0059] The first electrode and the second electrode remain in the LED assembly and may not be separately connected or removed. The first electrode and the second electrode may not be used in processes after assembly.

[0060] First insulating layer (40)

[0061] A first insulating layer (40) can be arranged to cover the substrate (10), the first electrode (20), and the second electrode (30).

[0062] If there is no first insulating layer on the first electrode and the second electrode, a short circuit may occur as the LED element is arranged between the first electrode and the second electrode.

[0063] A plurality of grooves (42) can be formed at regular intervals in the region between the first electrode and the second electrode within the first insulating layer.

[0064] The grooves (42) can be formed in the longitudinal direction and at regular intervals in the region between the first electrode and the second electrode. The grooves can induce a stronger electric field formation between the first electrode and the second electrode.

[0065] FIG. 2 is a cross-sectional view of an LED element aligned according to the present invention.

[0066] As shown in FIG. 2, the groove (42) is a space in which an LED element is placed, and it is preferable that the size of the groove be larger than the size of the LED element. When the size of the groove is larger than the size of the LED element, one LED element can be stably aligned inside one groove, and there is an advantage in increasing the contact area between the LED element and the transparent electrode.

[0067] In this regard, the length (D) of the groove (42) L It is preferable that ) is larger than the length of the LED element and the width of the groove is larger than the diameter of the LED element.

[0068] Length of the groove (D LThe distance between the region between the first electrode and the second electrode can be adjusted within a range where the alignment of the LED elements is smooth. Preferably, the length of the groove may be greater than the distance between the region between the first electrode and the second electrode. If the length of the groove is greater than the distance between the region between the first electrode and the second electrode, the LED elements inside the groove are aligned to an accurate position by the electric field formed between the first electrode and the second electrode.

[0069] In particular, by forming the length of the groove to be greater than the distance between the first electrode and the second electrode, the magnitude of the electric field is locally increased in the groove, which has an advantageous effect for aligning one LED element in one groove. In addition, to align one LED element in one groove, the length of the groove (D L ) can be less than or equal to twice the length of the LED element.

[0070] In addition, if the thickness of the first insulating layer between the bottom surface of the groove and the upper surface of the first electrode and the second electrode is too thick, the electric field strength in the region between the first electrode and the second electrode tends to decrease, so it is desirable to control the thickness. For example, the thickness of the first insulating layer between the bottom surface of the groove and the upper surface of the first electrode and the second electrode may be approximately 0.01 to 1 μm, but is not limited thereto.

[0071] LED element (50)

[0072] The LED element (50) is a micro-luminescent material with the longest side length being approximately 100 μm or less, and may be a nano LED element or a micro LED element.

[0073] LED elements are organic or / or inorganic materials dispersed in a fluid and have various sizes in 1D, 2D, or 3D shapes.

[0074] LED elements can be in the form of nanowires with length, flat disks, cubes with an aspect ratio of 1 to 2, cylinders, or core-shells.

[0075] Preferably, the LED device may be in the form of a nanowire with a high aspect ratio and have a length of 1 to 100 μm, and more preferably may be a device having a length of 1 to 80 μm.

[0076] The nanowire-shaped LED device may have an aspect ratio of 1 to 10, specifically 1 to 5. In addition, the nanowire-shaped LED device may have a cross-sectional diameter of approximately 10 to 10,000 nm, specifically 10 to 1,000 nm.

[0077] LED devices with a high aspect ratio have a large surface area, resulting in excellent energy transfer and performance, as well as the advantage of high transparency.

[0078] For example, a cylindrical LED element may include an n-type semiconductor layer, an active layer, and a p-type semiconductor layer.

[0079] For example, in a core-shell shaped LED device, the active layer surrounds the outer surface of the n-type semiconductor layer; therefore, light can be emitted from the entire area where the active layer is located. In other words, because the area of ​​the active layer in a core-shell structured LED device is relatively large, a large area for light emission can be secured.

[0080] An LED element with a core-shell structure may include a core formed of an n-type semiconductor layer located in the center along the longitudinal direction of the LED element, an active layer disposed on the surface of the core and surrounding at least one side of the n-type semiconductor layer, and a p-type semiconductor layer disposed on the surface of the active layer and surrounding the active layer.

[0081] Additionally, it may further include a metal layer (not shown) surrounding a p-type semiconductor layer and an insulating film (not shown) surrounding a portion of the outer surface of the metal layer, but is not limited thereto.

[0082] For example, an LED element may have a hexagonal pyramid shape that tapers at a single vertex as it narrows from the center upwards, or a square prism shape with a uniform width from the center downwards. As another example, the LED element may have a polygonal prism shape that narrows from top to bottom, or conversely, a polygonal prism shape that narrows from bottom to top.

[0083] In the present invention, a display having nano-sized pixels can be fabricated using an LED assembly having various types of LED elements, and high density and high resolution can be achieved.

[0084] FIG. 3 is a cross-sectional view of an LED element according to the present invention.

[0085] In Fig. 3, a nanowire-shaped LED element is illustrated, but this is merely one example and is not limited thereto.

[0086] In this invention, the form of the LED element is assumed to be a nanowire for explanation purposes.

[0087] As illustrated in FIG. 3, the LED element (50) may include an n-type semiconductor layer (51), an active layer (52) disposed on one side of the n-type semiconductor layer, a p-type semiconductor layer (53) disposed on one side of the active layer, a current dispersing layer (54) disposed on one side of the p-type semiconductor layer, and a passivation layer (55) covering the outer surface of the LED element.

[0088] The current dispersion layer (54) is placed to disperse current on the side of the p-type semiconductor layer, which has relatively high resistance. The current dispersion layer (54) may include one or more types of metals such as Al, Cu, Cr, Ni or / and transparent conductive oxide (TCO) materials such as ITO (Indium Tin Oxide) and FTO (Fluorine-doped Tin Oxide).

[0089] Meanwhile, if an electrode comes into contact with the active layer of an LED element, an electrical short circuit occurs, which can cause a failure in light emission.

[0090] To solve the short-circuit problem that occurs when an electrode touches the active layer of an LED element, a passivation layer, which is an insulating film, can be formed on the parts of the LED element excluding both ends.

[0091] The passivation layer can be a transparent material to increase the luminous efficiency of the LED element.

[0092] The passivation layer may include one or more insulating materials among SiO2, Si3N4, Al2O3, AlN, and TiO2, but is not limited thereto.

[0093] In the present invention, the ends of the LED element are etched to increase the contact area between the LED element and the first transparent electrode and between the LED element and the second transparent electrode, and to reduce electrical resistance.

[0094] In an LED device, a portion of the current distribution layer and a portion of the n-type semiconductor layer may be etched. Specifically, the sides of the current distribution layer and the sides of the n-type semiconductor layer may be partially etched. As shown in FIG. 1, the etched sides may have a shape in which the horizontal and vertical planes of the LED device are alternately etched.

[0095] For example, the etched side may include a vertical plane and a horizontal plane extending outward from the vertical plane, and may include at least one vertical plane and at least one horizontal plane.

[0096] The sides of the current distribution layer and the sides of the n-type semiconductor layer may refer to the sides at both ends of the LED element when viewed in the cross-sectional view of FIG. 1.

[0097] As shown in FIG. 1, when the ends of the LED element are etched, the current distribution layer (54), the n-type semiconductor layer (51), and the passivation layer (55) are etched, and depending on the degree of etching, the p-type semiconductor layer (53) may also be etched.

[0098] Second insulating layer (60)

[0099] As shown in FIG. 1, a second insulating layer may be disposed on the outer surface of an LED element with both ends etched, and a second insulating layer may be disposed in the center of the outer surface of the LED element so as to expose the passivation layer.

[0100] In the cross-sectional view of FIG. 1, a second insulating layer is shown placed on the upper part of the LED element, but this means that the second insulating layer is placed to surround the outer surface of the LED element.

[0101] The second insulating layer may be positioned at the center of the outer surface of the LED element in a shape that wraps around the center of the pillar on the outer surface of the LED element. Additionally, the second insulating layer may be positioned to wrap around a portion of the two sides located at both ends of the LED element.

[0102] Since a second insulating layer is present in the center of the outer surface of the LED element, the contact area between the first transparent electrode and the second transparent electrode with respect to the LED element can be widened, thereby having the effect of lowering the contact resistance between the LED element and the first transparent electrode and the second transparent electrode.

[0103] In addition, the second insulating layer is also deposited inside the groove, so that the second insulating layer can be further filled between both ends of the LED element and the side of the groove.

[0104] A second insulating layer exists between both ends of the LED element and the side of the groove, thereby preventing the LED element from detaching due to the solution or connection (short circuit) failures caused by the contact electrode (ITO connection).

[0105] In addition, the presence of a second insulating layer between both ends of the LED element and the side of the groove has the effect of reducing the leakage current inherent to the LED element itself.

[0106] At this time, the fact that a second insulating layer is further disposed between both ends of the LED element and the side of the groove means that it is filled up to a predetermined height from the bottom surface of the groove, but it is not filled up to the height of the LED element.

[0107] The thickness of the second insulating layer may be 150 to 500 nm, and preferably 200 to 350 nm. By satisfying a thickness of 150 to 500 nm, the contact area between the first transparent electrode and the second transparent electrode can be secured widely, thereby having the effect of lowering the contact resistance between the LED element and the first transparent electrode and the second transparent electrode. Accordingly, the occurrence of defects in the LED assembly can be prevented, and higher yield and efficiency can be secured.

[0108] The second insulating layer is formed from a composition comprising a silicate polymer, an organic solvent, and distilled water, and may include a silicate polymer.

[0109] First transparent electrode (70) and second transparent electrode (80)

[0110] As shown in FIG. 1, the first transparent electrode and the second transparent electrode may be spaced apart from each other to surround both ends of the LED element and the second insulating layer.

[0111] The first transparent electrode can contact the upper surface and side of the second insulating layer, and can contact the side of the current dispersing layer of the LED element, the inner surface of the groove, and the outer surface of the groove.

[0112] The first transparent electrode can be extended in one direction and connected to the source electrode or drain electrode of a transistor disposed on the substrate.

[0113] The second transparent electrode can contact the upper surface and side of the second insulating layer, and can contact the side of the n-type semiconductor layer of the LED element, the inner surface of the groove, and the outer surface of the groove.

[0114] The second transparent electrode extends in one direction to the power supply voltage line (V DD It can be connected to the base voltage line (Vss) or the base voltage line.

[0115] The first transparent electrode and the second transparent electrode may include transparent conductive oxide (TCO) materials such as ITO (Indium Tin Oxide) and FTO (Fluorine-doped Tin Oxide).

[0116] The thickness of the transparent electrode can be 100 to 200 nm, and preferably 125 to 160 nm.

[0117] By satisfying a thickness of 100 to 200 nm for the transparent electrode, it has the effect of lowering the resistance of the applied current.

[0118] As such, the LED assembly of the present invention has the effect of improving electrical contact by aligning the LED element at an accurate position inside the groove and simultaneously increasing the contact area between the LED element and the first transparent electrode and the second transparent electrode through lateral etching of the LED element.

[0119] FIG. 4 is a flowchart of a method for manufacturing an LED assembly according to the present invention, and FIG. 5 is a schematic diagram showing the manufacturing steps of an LED assembly according to the present invention.

[0120] As illustrated in FIGS. 4 and 5, the method for manufacturing an LED assembly according to the present invention may include the steps of: aligning an LED element in a groove (S110); forming a second insulating layer by depositing a composition for a second insulating layer to cover the LED element (S120); etching the second insulating layer to expose a portion of the outer surface of the LED element and both ends (S130); etching both ends of the LED element (S140); and forming a first transparent electrode and a second transparent electrode spaced apart from each other to surround both ends of the LED element and the second insulating layer (S150).

[0121] Step of aligning LED elements in the home (S110)

[0122] A first electrode (20) and a second electrode (30) are spaced apart from each other on a substrate (10), and a first insulating layer (40) is provided that covers the first electrode and the second electrode and includes a groove (42) in the area between the first electrode and the second electrode, and an LED element (50) can be aligned in the groove.

[0123] Specifically, after placing a metal layer on a substrate (10), a portion of the metal layer can be etched to form a first electrode and a second electrode spaced apart from each other.

[0124] In general, display circuits require a large amount of metal wiring because LED elements must be connected via electrodes. Consequently, during the LED assembly process using an electric field, parasitic electric fields can be generated in unwanted locations, so it is important to minimize this phenomenon.

[0125] To this end, it is desirable to form a metal layer (not shown) over the entire area to cover all components of the circuit. The metal layer can serve as an electric field shielding layer and also align the LED components. Furthermore, by forming the metal layer over the entire area of ​​the substrate, the formation of parasitic electric fields can be minimized while simultaneously protecting the components located beneath the metal layer from the electric field. A first electrode and a second electrode can be formed spaced apart from each other from this metal layer, and the first and second electrodes can generate an electric field.

[0126] Next, a first insulating layer (40) can be arranged to cover the substrate, the first electrode, and the second electrode. In the first insulating layer (40), a plurality of grooves can be formed at regular intervals in the region between the first electrode and the second electrode.

[0127] The first insulating layer (40) can be formed from a polymer-based organic or / and inorganic material, and may include, for example, Al2O3, SiO2, etc.

[0128] A method for forming a groove in the first insulating layer (40) can be achieved using photoresist and etching. The etching can be a dry etching method such as sputter etching using an inert gas, ions, etc., plasma etching, or a wet etching method using a chemical reaction with a solution.

[0129] When a groove is formed in the region between the first electrode and the second electrode, a relatively high electric field is formed in the groove, and a strong attractive force is generated in that part, so the alignment of the LED element (50) in the groove becomes easier.

[0130] As described above, the length of the groove may be greater than the length of the LED element, and the width of the groove may be greater than the diameter of the LED element. Additionally, the length of the groove may be greater than the distance of the region between the first electrode and the second electrode.

[0131] In this structure, when observed in a planar view, one end of the LED element is placed on the first electrode and the other end of the LED element is placed on the second electrode, so that the two ends of the LED element overlap on the first electrode and the second electrode.

[0132] Step (S120) of forming a second insulating layer by depositing a composition for the second insulating layer to cover the LED element

[0133] It is preferable to flatten the upper surface while the LED element (50) is aligned in the home and to fix the LED element (50) by depositing a second insulating layer (60) on the entire surface of the LED element.

[0134] The second insulating layer (60) can be deposited and filled inside the groove as well to wrap around the outer surface of the LED element. As a result, the second insulating layer is fully deposited on the upper surface of the LED element and the first insulating layer, and can have a predetermined thickness.

[0135] The second insulating layer can be manufactured as follows.

[0136] First, a substrate made of silicon, glass, or plastic is mounted on a vacuum chuck.

[0137] Subsequently, the composition for the second insulating layer is distributed to the center of the substrate. It is rotated at an RPM speed according to the desired thin film thickness. Due to the centrifugal force caused by the rotation, the composition for the second insulating layer spreads evenly across the entire surface of the substrate, and a thin film is formed after the solvent evaporates rapidly. The second insulating layer formed in this way allows for precise control of film thickness and planarization through a spin process, and enables the fixation of LED elements within the groove.

[0138] The composition for the second insulating layer may include a silicate polymer, an organic solvent, and distilled water. Specifically, it may include 1 to 10 weight% of a silicate polymer and the remainder being an organic solvent and distilled water. More specifically, the composition for the second insulating layer may include 1 to 10 weight% of a silicate polymer, 30 to 50 weight% of isopropyl alcohol, 10 to 30 weight% of acetone, and 10 to 30 weight% of reagent alcohol.

[0139] Based on the upper surface of the LED element, the thickness of the second insulating layer deposited may be 100 to 150 nm, but is not limited thereto.

[0140] Step (S130) of etching the second insulating layer to expose a portion of the outer surface and both ends of the LED element

[0141] To expose the contact area of ​​the LED element, the second insulating layer can be etched.

[0142] The second insulating layer can be etched so that the second insulating layer remains in the lower region of the LED element, and the second insulating layer remains in the center of the outer surface of the LED element.

[0143] Regarding the etching of the second insulating layer, since it is impossible to deposit a portion of the second insulating layer using photoresist, it is preferable to etch the second insulating layer after depositing it over the entire surface.

[0144] Etching the second insulating layer means exposing both ends and a portion of the outer surface of the LED element.

[0145] In the step of etching the second insulating layer, photoresist (PR) and dry etching can be used.

[0146] Photoresist (PR) is a photosensitive material containing organic solvents and polymer materials. After spin-coating the photoresist, the organic solvent within the photoresist can be removed. Photoresist forms a pattern using light and is classified into negative and positive types. In negative PR, particles clump together when exposed to light, so the unexposed areas are removed when light is shone on them. In positive PR, the areas exposed to light react; since polymer bonds break when exposed to light, only the areas exposed to light are removed when light is shone on them.

[0147] When etching the second insulating layer, dry etching can be performed in a gas atmosphere of one or more of carbon tetrafluoride (CF4) and fluoroform (CHF3).

[0148] In dry etching, in addition to the gas used, the pressure inside the chamber, the amount of plasma generated, the force pulling the plasma, the temperature at which the PR does not burn, and the mixing ratio of the gases used (etch type) can be controlled.

[0149] The upper and lower regions of the second insulating layer can be distinguished based on the LED element shown in FIGS. 1 and FIGS. 5. The upper region of the second insulating layer is the region outside the groove, and the lower region of the second insulating layer is the region where the LED element is located inside the groove.

[0150] Meanwhile, among the upper and lower regions of the second insulating layer, the upper region is completely etched and a portion of the lower region is etched, and then the composition for the second insulating layer can be deposited on the center of the outer surface of the LED element; however, since the composition for the second insulating layer is applied in a full-surface deposition or full-surface coating form, there is a problem in that deposition and etching are difficult with this method.

[0151] Therefore, as described above, it is preferable to deposit the second insulating layer on the front surface and then etch it so that the second insulating layer remains in the inner region of the groove and in the center of the outer surface of the LED element.

[0152] Step of etching both ends of the LED element (S140)

[0153] To increase the contact area between the first transparent electrode and the second transparent electrode for the LED element, both ends of the LED element can be etched.

[0154] Etching both ends of the LED element may mean etching the side of the current distribution layer and the side of the n-type semiconductor layer placed on one side of the p-type semiconductor layer as seen in the cross-sectional view of FIG. 1. Due to the etching, the side of the LED element may have a shape in which horizontal and vertical planes are alternately etched.

[0155] Dry etching methods such as sputter etching using inert gas, ions, etc., and plasma etching can be used for etching.

[0156] When etching both ends of the LED element, one or more gases among chlorine (Cl2) and boron boride (BCl3) may be used.

[0157] When etching the second insulating layer and both ends of the LED element at once, one or more of chlorine (Cl2) and boron boride (BCl3) may be used.

[0158] However, since the second insulating layer and the LED element are made of different materials, their etching rates differ, so it is desirable to use different types of gases for each.

[0159] Step (S150) of forming a first transparent electrode and a second transparent electrode spaced apart from each other to surround both ends of the LED element and the second insulating layer

[0160] As shown in FIG. 5, the first transparent electrode and the second transparent electrode can be formed spaced apart from each other to surround both ends of the LED element and the second insulating layer.

[0161] Specifically, the method may include the steps of: depositing a transparent electrode to surround both ends of an LED element and a second insulating layer; patterning a photoresist on the transparent electrode to form a first transparent electrode and a second transparent electrode apart; and removing the photoresist.

[0162] In the step of depositing a transparent electrode, it can be deposited by physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALD).

[0163] Specifically, PVD can be performed by thermal evaporation, electron beam evaporation, plasma laser deposition (PLD), or sputtering.

[0164] CVD can be performed using Metal Organic Chemical Vapor Deposition (MOCVD), Atmospheric Pressure Chemical Vapor Deposition (APCVD), Low Pressure Chemical Vapor Deposition (LPCVD), Enhanced Chemical Vapor Deposition (PECVD), High Density Plasma Chemical Vapor Deposition (HDPCVD), and Atomic Scale Chemical Vapor Deposition (ALCVD).

[0165] In the step of forming the first transparent electrode and the second transparent electrode apart, the photoresist can be patterned so that the central part of the upper portion of the deposited transparent electrode is removed.

[0166] The first transparent electrode and the second transparent electrode, which are etched and spaced apart, can come into contact with the second insulating layer and the side of the LED element and the side of the groove with a uniform thickness.

[0167] The first transparent electrode can be connected to the source electrode or drain electrode of a transistor disposed on the substrate.

[0168] The second transparent electrode is the power supply voltage line (V DD It can be connected to the base voltage line (Vss) or the base voltage line.

[0169] As such, the LED assembly and the manufacturing method according to the present invention have the effect of improving electrical contact and providing excellent luminous efficiency by etching both ends of an LED element fixed inside a groove, thereby increasing a uniform contact area between the LED element and the transparent electrode instead of an uneven contact area caused by the fracture surface of the LED element.

[0170] Although the present invention has been described above with reference to the illustrated drawings, the present invention is not limited by the embodiments and drawings disclosed in this specification, and it is obvious that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration according to the present invention were not explicitly described while explaining the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized.

Claims

1. Substrate; A first electrode and a second electrode spaced apart from each other on the above substrate; A first insulating layer covering the first electrode and the second electrode, comprising a groove in the region between the first electrode and the second electrode; LED element aligned with the above groove and having both ends etched; A second insulating layer disposed on top of the LED element having both ends etched; and An LED assembly comprising: a first transparent electrode and a second transparent electrode spaced apart from each other to surround both ends of the LED element and a second insulating layer.

2. In Paragraph 1, An LED assembly in which the length of the groove is greater than the length of the LED element and the width of the groove is greater than the diameter of the LED element.

3. In Paragraph 1, An LED assembly in which the length of the above groove is greater than the distance between the first electrode and the second electrode.

4. In Paragraph 1, The above LED element comprises an n-type semiconductor layer, an active layer disposed on one side of the n-type semiconductor layer, a p-type semiconductor layer disposed on one side of the active layer, a current dispersing layer disposed on one side of the p-type semiconductor layer, and a passivation layer covering the outer surface of the LED element.

5. In Paragraph 4, The above LED element is an LED assembly in which the sides of the current distribution layer and the sides of the n-type semiconductor layer are etched.

6. In Paragraph 1, The above second insulating layer is an LED assembly comprising a silicate polymer.

7. In Paragraph 1, The above second insulating layer is further disposed between the two ends of the LED element and the side of the groove in an LED assembly.

8. In Paragraph 1, An LED assembly in which one LED element is aligned in one of the above-mentioned grooves.

9. (a) A first electrode and a second electrode spaced apart from each other on a substrate, a first insulating layer covering the first electrode and the second electrode, the insulating layer including a groove in the region between the first electrode and the second electrode, and aligning an LED element in the groove; (b) a step of forming a second insulating layer by depositing a composition for a second insulating layer to cover the LED element; (c) a step of etching the second insulating layer to expose a portion of the outer surface of the LED element and both ends; (d) a step of etching both ends of the LED element; and (e) a step of forming a first transparent electrode and a second transparent electrode spaced apart from each other to surround both ends of the LED element and the second insulating layer; a method for manufacturing an LED assembly.

10. In Paragraph 9, A method for manufacturing an LED assembly in step (a) above, wherein the length of the groove is greater than the length of the LED element and the width of the groove is greater than the diameter of the LED element.

11. In Paragraph 9, The above (c) step A method for manufacturing an LED assembly by etching a second insulating layer such that the second insulating layer remains in the inner region of the above-mentioned home and in the center of the outer surface of the LED element.

12. In Paragraph 9, In step (d) above, a method for manufacturing an LED assembly in which the LED element is etched from the side of a current distribution layer disposed on one side of a p-type semiconductor layer and the side of an n-type semiconductor layer.

13. In Paragraph 9, In the above (e) step, (e1) A step of depositing a transparent electrode to surround both ends of the LED element and the second insulating layer; (e2) patterning a photoresist on the transparent electrode to form a first transparent electrode and a second transparent electrode spaced apart; and (e3) A step of removing the photoresist; a method for manufacturing an LED assembly comprising.

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