LED assembly with low contact resistance and method for manufacturing same

Abstract

A method for manufacturing an LED assembly according to the present invention is characterized by comprising: (a) a step for preparing a structure including a substrate, a first electrode layer and a second electrode layer spaced apart from each other on the substrate, an insulating layer covering the first electrode layer and the second electrode layer and including a groove in a region between the first electrode layer and the second electrode layer, and an LED element aligned with the groove; (b) a step for filling a gap between the insulating layer and the LED element by coating the upper surface of the structure with a silicon oxide solution; (c) a step for patterning a first photoresist on the coated silicon oxide layer; (d) a step for etching the insulating layer and the silicon oxide layer by means of a first photoresist and then removing the first photoresist; (e) a step for depositing a transparent electrode on the etched structure; (f) a step for patterning, on the transparent electrode, a second photoresist for separating the transparent electrode; and (g) a step for etching the transparent electrode by means of a second photoresist and then removing the second photoresist.

Description

LED assembly with low contact resistance and method for manufacturing the same

[0001] The present invention relates to an LED assembly having low contact resistance between an LED element and a transparent electrode, and a manufacturing method thereof, by forming a silicon oxide layer between the LED element and the transparent electrode and forming a slope in a groove.

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

[0003] Detailed project number: 00467525, Ministry of SMEs and Startups, Project management agency: Korea Technology Information Promotion Agency for Small and Medium Businesses, Research project name: Startup Growth Technology Development Project (Stepping Stone), Research project name: Development of submicron ultra-small LED-based fluid-based transfer technology and display panel manufacturing technology, Project implementing organization: Advanced View Technology Co., Ltd., Research period: 2024.08.01-2025.07.31

[0004] In order to utilize LED elements for lighting, displays, etc., an LED element and an electrode capable of supplying power to the LED element are required. Various arrangements of the LED element and two different electrodes are being studied in relation to the purpose of use, reduction of the space occupied by the electrode, or manufacturing method.

[0005] For example, a method of arranging LED elements on electrodes after growing them independently is a method of arranging each LED element individually on a patterned electrode.

[0006] However, when the size of the LED element is ultra-small in the nanometer scale, it is very difficult to place the LED element on two different ultra-small electrodes within the intended range, and even if the LED element is placed on two different ultra-small electrodes, there is a problem in that the intended electrode assembly cannot be realized due to frequent defects caused by electrical short-circuiting between the electrodes and the ultra-small LED element.

[0007] In addition, when independently grown LED elements are placed on an electrode and power is applied to the electrode, there is a problem that contact resistance occurs between the LED element and the electrode, resulting in a decrease in light extraction efficiency.

[0008] Therefore, there is a need for research on an LED assembly with improved electrical contact that can not only increase conductivity between the LED element and the electrode but also reduce contact resistance.

[0009] An object of the present invention is to provide an LED assembly capable of securing a contact area between an LED element and a transparent electrode.

[0010] Another object of the present invention is to provide an LED assembly capable of maintaining the alignment position of LED elements even when the size of the groove of the insulating layer is large.

[0011] Another object of the present invention is to provide an LED assembly having no defects or failures and excellent yield.

[0012] Another object of the present invention is to provide a method for manufacturing an LED assembly in which the structure can be changed so that the side surface of the groove of the insulating layer has an inclined surface.

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

[0014] A method for manufacturing an LED assembly according to the present invention comprises the steps of: (a) providing a structure including a substrate, a first electrode layer and a second electrode layer spaced apart from each other on the substrate, an insulating layer covering the first electrode layer and the second electrode layer and including a groove in a region between the first electrode layer and the second electrode layer, and an LED element aligned in the groove; (b) coating a silicon oxide solution on an upper surface of the structure to fill a gap between the insulating layer and the LED element; (c) patterning a first photoresist on the coated silicon oxide layer; (d) etching the insulating layer and the silicon oxide layer by the first photoresist and then removing the first photoresist; (e) depositing a transparent electrode on the etched structure; (f) patterning a second photoresist on the transparent electrode to separate the transparent electrodes; And (g) a step of removing the second photoresist after etching the transparent electrode by the second photoresist.

[0015] The above silicon oxide solution may include a silicate polymer, an organic solvent, and distilled water.

[0016] The thickness of the above silicon oxide layer may be 100 to 150 nm.

[0017] In the above step (b), the gap between the insulating layer and the LED element can be filled to fix the LED element to the groove.

[0018] In the above step (b), the coated silicon oxide solution is first heat-treated at 80 to 430°C, then second and third heat-treated, and the first heat-treatment temperature (T1) < second heat-treatment temperature (T2) < third heat-treatment temperature (T3) can be satisfied.

[0019] The step (c) above may include a step of (c1) patterning a first photoresist on the coated silicon oxide layer; and a step of (c2) heat-treating the patterned first photoresist to form an inclined surface on a side surface of the first photoresist.

[0020] In the above step (c2), heat treatment can be performed at 110 to 150°C.

[0021] The step (d) above may include (d1) a step of etching the side of the insulating layer, the side of the silicon oxide layer, and the side of the silicon oxide layer present on the upper portion of the LED element so that they have an inclined surface by the first photoresist; and (d2) a step of removing the first photoresist.

[0022] In the above step (g), the first transparent electrode and the second transparent electrode, which are etched and separated, can contact the side surface of the LED element and the silicon oxide layer present on the top and bottom of the LED element.

[0023] One micro LED element can be aligned in one of the above grooves.

[0024] A method for manufacturing an LED assembly according to another embodiment of the present invention is characterized by comprising the steps of: providing a structure including a substrate, a first electrode layer and a second electrode layer spaced apart from each other on the substrate, an insulating layer covering the first electrode layer and the second electrode layer and including a groove in a region between the first electrode layer and the second electrode layer, and an LED element aligned in the groove; filling a gap between the insulating layer and the LED element; etching the insulating layer and the silicon oxide layer; depositing a transparent electrode on the etched structure; and etching the transparent electrode.

[0025] An LED assembly according to the present invention is characterized by including: a substrate; a first electrode layer and a second electrode layer spaced apart from each other on the substrate; an insulating layer covering the first electrode layer and the second electrode layer and including a groove in a region between the first electrode layer and the second electrode layer; an LED element aligned in the groove; a silicon oxide layer disposed on an upper portion of the insulating layer and on an upper and lower portion of the LED element; and a first transparent electrode and a second transparent electrode spaced apart from each other so as to surround a side surface of the LED element and the silicon oxide layer.

[0026] The side of the above home may have a slope.

[0027] The LED assembly and its manufacturing method according to the present invention have the effect of lowering contact resistance by filling the gap between the insulating layer and the LED element using a silicon oxide solution to fix the LED element, and then making the side surface of the insulating layer have an inclined surface, thereby securing a contact area between the LED element and the transparent electrode.

[0028] In addition, by applying a silicon oxide layer, the alignment position of the LED element can be maintained even if the size of the groove of the insulating layer is large, and the occurrence of defects and failures in the LED element can be prevented, resulting in an excellent yield.

[0029] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0030] Figure 1 is a flowchart showing a method for manufacturing an LED assembly according to the present invention.

[0031] Figure 2 is a schematic diagram showing a method for manufacturing an LED assembly according to the present invention.

[0032] [Explanation of symbols]

[0033] 10: Substrate

[0034] 22: First electrode layer

[0035] 24: Second electrode layer

[0036] 30: Insulating layer

[0037] 32: Home

[0038] 35: LED element

[0039] 40: Silicon oxide layer

[0040] 50: First photo resist

[0041] 60: Transparent electrode

[0042] 62: First transparent electrode

[0043] 64: Second transparent electrode

[0044] 70: Second photo resist

[0045] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if a detailed description of a known technology related to the present invention is judged to unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0046] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0047] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0048] Hereinafter, a low contact resistance LED assembly and a manufacturing method thereof according to some embodiments of the present invention will be described.

[0049] In the present invention, contact resistance refers to resistance that occurs in the contact between structures that electrically connect multiple films on a wafer, and by lowering this contact resistance, the defect rate of a product can be lowered.

[0050] FIG. 1 is a flowchart showing a method for manufacturing an LED assembly according to the present invention, and FIG. 2 is a schematic diagram of a method for manufacturing an LED assembly.

[0051] As illustrated in FIGS. 1 and 2, a method for manufacturing an LED assembly may include a step of providing a structure including a substrate, a first electrode layer and a second electrode layer spaced apart from each other on the substrate, an insulating layer covering the first electrode layer and the second electrode layer and including a groove in a region between the first electrode layer and the second electrode layer, and an LED element aligned in the groove (S110), a step of filling a gap between the insulating layer and the LED element by coating a silicon oxide solution (S120), a step of patterning a first photoresist (S130), a step of removing the first photoresist after etching the insulating layer and the silicon oxide layer (S140), a step of depositing a transparent electrode on the etched structure (S150), a step of patterning a second photoresist for spaced-apart separation of the transparent electrodes (S160), and a step of removing the second photoresist after etching the transparent electrodes (S170).

[0052] A step (S110) of preparing a structure including a substrate, a first electrode layer and a second electrode layer spaced apart from each other on the substrate, an insulating layer covering the first electrode layer and the second electrode layer but including a groove in an area between the first electrode layer and the second electrode layer, and an LED element aligned in the groove

[0053] As illustrated in FIG. 2, when viewed from the cross-sectional side, the structure has a structure in which an insulating layer (30) is disposed on a substrate on which a first electrode layer (22) and a second electrode layer (24) are spaced apart, and an LED element (35) is assembled into a groove (32) of the insulating layer. At this time, it is preferable that one LED element (35) is assembled into one groove (32) formed in the insulating layer (30), and this structure is maintained until the final step of patterning the transparent electrode (60).

[0054] The substrate (10) may be an active matrix backplane.

[0055] Each of the first electrode layer (22) and the second electrode layer (24) 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] The thickness of the first electrode layer and the second electrode layer may be 10 nm to 100 nm, but is not limited thereto.

[0057] An insulating layer (30) can be placed to cover all of the substrate (10), the first electrode layer (22), and the second electrode layer (24).

[0058] If there is no insulating layer on the first electrode layer and the second electrode layer, a short may occur when the LED element is arranged between the first electrode layer and the second electrode layer.

[0059] A plurality of grooves can be formed at regular intervals in a region corresponding to the area between the first electrode layer and the second electrode layer among the insulating layers. The insulating layer corresponding to the region between the first electrode layer and the second electrode layer can be patterned to a certain thickness to form grooves (32) for inducing the formation of an electric field in the substrate.

[0060] As illustrated in step S110 of FIG. 2, the groove (32) is a space where the LED element is placed, and the size of the groove is preferably larger than the size of the LED element. The length of the groove and the distance between the first electrode layer and the second electrode layer can be adjusted within a range that allows smooth alignment of the LED element. The length of the groove is preferably larger than the distance between the first electrode layer and the second electrode layer.

[0061] By forming the length of the groove (32) to be greater than the distance between the first electrode layer and the second electrode layer, it is possible to locally increase the size of the electric field and obtain an advantage in selectively aligning the LED elements.

[0062] Additionally, to align one LED element in one groove, the length of the groove may be greater than the length of the LED element and may be less than or equal to twice the length of the LED element.

[0063] In addition, if the thickness of the insulating layer between the groove and the electrode layer is too thick, the intensity of the electric field in the region between the first electrode layer and the second electrode layer tends to decrease, so it is desirable to have an appropriate thickness. For example, the thickness of the insulating layer between the groove and the first electrode layer and the second electrode layer may be approximately 0.01 to 1 ㎛, and specifically, may be 0.1 to 1 ㎛, but is not limited thereto.

[0064] LED elements are ultra-small light-emitting materials with a longest side length of approximately 100 μm or less, and may be nano LED elements or micro LED elements. These LED elements are made of organic or / and inorganic materials dispersed in a fluid and have various sizes in 1D, 2D, or 3D shapes.

[0065] The LED element may be in the form of a nanowire having a length, a flat and flat disk shape, a cube shape having an aspect ratio of 1 to 2, a cylinder shape, or a core-shell shape. Preferably, the LED element may be a device having a high aspect ratio and a nanowire shape and having a length of 1 to 100 μm, preferably a device having a length of 1 to 80 μm. The nanowire-shaped LED element may have an aspect ratio of approximately 1 to 10, preferably 1 to 5. In addition, the nanowire-shaped LED element may have a cross-sectional diameter of approximately 10 to 10,000 nm, preferably 10 to 1,000 nm.

[0066] High aspect ratio LED elements have a large surface area, which allows for superior energy transfer and performance, as well as high transparency.

[0067] For example, a cylindrical LED element may include an n-type semiconductor layer, an active layer, and a p-type semiconductor layer.

[0068] For example, since a core-shell LED device is configured such that the active layer surrounds the outer surface of the n-type semiconductor layer, light can be emitted from all areas along the active layer's location. In other words, since a core-shell LED device has a relatively large active layer area, it can secure a large area from which light is emitted.

[0069] An LED element having a core-shell structure may include a core formed of an n-type semiconductor layer positioned in the center along the length direction of the LED element, an active layer disposed on a surface of the core and surrounding at least one side of the n-type semiconductor layer, and a p-type semiconductor layer disposed on a surface of the active layer and surrounding the active layer. In addition, the LED element may further include a metal layer (not shown) surrounding the 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.

[0070] For example, the LED element may have a hexagonal pyramid shape that narrows from the center to the top and touches a single vertex, or a square column shape that has the same width from the center to the bottom. As another example, the LED element may have a polygonal column shape that narrows from the top to the bottom, or conversely, a polygonal column shape that narrows from the bottom to the top.

[0071] The LED element has the same configuration as a commonly used LED element, and may include an n-type semiconductor layer, a p-type semiconductor layer, and an active layer interposed between the n-type semiconductor layer and the p-type semiconductor layer. The LED element may further include, but is not limited to, an electrode for current distribution on the side of the p-type semiconductor layer having relatively high resistance. Here, the electrode may include at least one of a metal such as Al, Cu, Cr, Ni, and / or a transparent conductive oxide (TCO) material such as ITO (Indium Tin Oxide) and FTO (Fluorine-doped Tin Oxide).

[0072] Step of filling the gap between the insulating layer and the LED element by coating a silicon oxide solution (S120)

[0073] When a silicon oxide solution is applied to the upper surface of the structure and the silicon oxide solution is applied between the insulating layer (30) and the LED element (35), the silicon oxide solution first fills the gap between the insulating layer and the LED element, and a thin film silicon oxide layer (40) covering the upper surface of the insulating layer and the LED element can be formed.

[0074] Coating with a silicon oxide solution is done by spin coating. After mounting a substrate made of silicon, glass, or plastic on a vacuum chuck, a small amount of silicon oxide solution is distributed to the center of the substrate, and the substrate is rotated at a speed of rpm according to the desired film thickness. The centrifugal force from the rotation causes the silicon oxide solution to spread evenly over the entire surface of the substrate, rapidly evaporating the solvent, and forming a thin film.

[0075] By coating the upper surface of the structure with a silicon oxide solution in this way, the gap between the insulating layer and the LED element can be filled, and the film thickness can be precisely controlled through a spin process, forming a flattened thin film. In addition, by filling the gap between the insulating layer and the LED element, the LED element (35) can be fixed to the groove (32).

[0076] At this time, after coating the silicon oxide solution, the coated silicon oxide solution is heat-treated in stages to slowly evaporate the solvent, thereby reducing the thermal shock and ensuring the flatness of the silicon oxide layer.

[0077] From this perspective, the silicon oxide solution may be heat-treated in a soft bake step and a hard bake step. The soft bake step may include a first to a third heat treatment, and the hard bake may heat-treat the third heat-treated silicon oxide layer at 410 to 430°C, preferably at 415 to 425°C.

[0078] Soft bake is performed by first heat treatment at 80 to 280℃, followed by second and third heat treatments, and can satisfy the condition of first heat treatment temperature (T1) < second heat treatment temperature (T2) < third heat treatment temperature (T3). Since the first to third heat treatments are performed in steps, the first heat treatment temperature can be 80 to 100℃, the second heat treatment temperature can be 130 to 180℃, and the third heat treatment temperature can be 230 to 280℃. After that, hard bake can be performed and then cooled to room temperature. The stepwise heat treatment of the silicon oxide solution can be performed using hot plate and furnace equipment.

[0079] If the silicon oxide solution is not heat-treated or is heat-treated at a temperature below 80°C, the silicon oxide layer may exhibit a sticky or soft liquid state rather than a thin film, which may cause defects in the first photoresist patterning process. Conversely, if the silicon oxide solution is heat-treated at a temperature exceeding 430°C, the flatness of the silicon oxide layer may be insufficient due to thermal shock. In addition, if the stepwise heat treatment is not performed, the problem of the high solvent evaporation rate, which increases the thermal shock, may occur.

[0080] Therefore, it is preferable to pattern the first photoresist (50) on the silicon oxide layer (40) after coating the silicon oxide solution and performing stepwise heat treatment by gradually increasing the temperature.

[0081] The silicon oxide solution may be an insulator and may include a silicate polymer, an organic solvent, and distilled water. Specifically, the silicon oxide solution may include 1 to 10 wt% of a silicate polymer and the remainder being an organic solvent and distilled water. More specifically, the silicon oxide solution may include 1 to 10 wt% of a silicate polymer, 30 to 50 wt% of isopropyl alcohol, 10 to 30 wt% of acetone, and 10 to 30 wt% of a reagent alcohol.

[0082] The above isopropyl alcohol, acetone, and reagent alcohol are organic solvents.

[0083] The thickness of the silicon oxide layer (40) may be 150 to 500 nm, and preferably 300 to 350 nm. By satisfying the thickness of the silicon oxide layer of 150 to 500 nm, a wide contact area between the LED element and the transparent electrode can be secured, thereby having the effect of lowering the contact resistance between the LED element and the transparent electrode. Accordingly, the occurrence of defects in the LED assembly can be prevented, and higher yield and efficiency can be secured.

[0084] This silicon oxide layer is a high-density silicon oxide layer, with a density of 2.27 (20°C) to 2.65 (25°C) g / cm, which is the density of existing commercialized silicon oxide layers. 3 Higher density 4.14(20℃) ~ 4.46(25℃)g / cm 3 It can be expressed as . Since the silicon oxide layer exhibits high density, it can provide the effect of reducing the defect (leakage) of the LED element itself.

[0085] Step of patterning the first photoresist (S130)

[0086] Etching can be performed by patterning a first photoresist (50) on a coated silicon oxide layer (40). Specifically, the method may include (c1) a step of patterning the first photoresist on the coated silicon oxide layer and then performing a heat treatment, and (c2) a step of forming an inclined surface on a side surface of the heat-treated first photoresist.

[0087] In order to etch the side surface of the above groove (32) so that it is inclined, the first photoresist can be applied to the upper surface of the silicon oxide layer, in the upper direction of the LED element and in both directions of the LED element.

[0088] Photoresist is a light-sensitive material that contains an organic solvent and a polymer. After spin-coating the photoresist, the organic solvent within the photoresist can be removed. Photoresists use light to form patterns and are categorized as negative and positive. Negative photoresists cause particles to clump together when exposed to light, so when exposed to light, the unexposed portion is removed. Positive photoresists react only to the light-exposed area. When exposed to light, the polymer bonds break, so when exposed to light, only the exposed portion is removed.

[0089] In S130 of Fig. 2, it is illustrated as a positive PR, but is not limited thereto.

[0090] After patterning the first photoresist (50), a heat treatment can be performed to form an inclined surface on the side surface of the first photoresist (50). When the first photoresist is heat treated, the remaining first photoresist is evaporated, and during the evaporation process, shrinkage of the first photoresist occurs, which can form an angle on the surface. In particular, the angle of the inclined surface forming the side surface of the first photoresist can be adjusted depending on the heat treatment temperature. Additionally, by heat treating the first photoresist, the residual organic solvent remaining in the soft bake step is removed, thereby improving the adhesion between the first photoresist and the substrate, thereby increasing the resistance in the subsequent etching step.

[0091] As shown in Fig. 2, the slope may be at an angle satisfying 40 to 50° from the vertical to the floor surface, but is not limited thereto.

[0092] The above heat treatment can be performed at 110 to 150°C, and preferably at 120 to 140°C. By satisfying the heat treatment temperature of 110 to 150°C, there is an effect of facilitating interconnection between the transparent electrode and the LED element.

[0093] Step of removing the first photoresist after etching the insulating layer and silicon oxide layer (S140)

[0094] After dry etching the insulating layer (30) and the silicon oxide layer (40) using the first photoresist (50), the first photoresist (50) can be removed.

[0095] Specifically, (d1) a step of etching the side surface of the insulating layer (30), the side surface of the silicon oxide layer (40), and the side surface of the silicon oxide layer (40) present on the upper portion of the LED element to have an inclined surface by the first photoresist (50), and (d2) a step of removing the first photoresist (50).

[0096] When etching is performed, dry etching is performed anisotropically from the end of the thinnest thickness of the first photoresist, so that when viewed from the side in cross-section as shown in S140, a groove structure having a slope that slopes outward from the bottom to the top can be displayed.

[0097] Anisotropic etching is an etching speed that varies depending on the direction, so etching can occur in a specific direction, and the etched shape can be closer to a vertical shape than a round shape.

[0098] In dry etching, one or more gases among chlorine (Cl2), boron carbide (BCL3), carbon tetrafluoride (CF4), fluoroform (CHF3), and argon (Ar) can be used, and can be performed at -5 to 5°C, and preferably, one or more gases among carbon tetrafluoride (CF4), fluoroform (CHF3), and argon (Ar) can be used.

[0099] The dry etching time can be performed for 100 to 200 seconds, preferably for 140 to 180 seconds, and more preferably for 150 to 170 seconds.

[0100] The structure remaining by etching may be the silicon oxide layer (40) present on the upper and lower portions of the LED element, the inclined surfaces of the insulating layer (30) present on both sides of the LED element, and the inclined surfaces of the silicon oxide layer (40). In addition, since the side surface of the first photoresist has an inclined surface, the side surface of the silicon oxide layer present on the upper portion of the LED element can also be etched to have an inclined surface. The silicon oxide layer is completely removed and does not remain on the surface of the n-type semiconductor layer and the surface of the p-type semiconductor layer, which are the side surfaces of the LED element.

[0101] Additionally, as the area of ​​the bottom surface of the groove becomes wider due to etching at step S140, the area of ​​the bottom surface of the groove at step S140 may be larger than the area of ​​the bottom surface of the groove at step S110.

[0102] Step of depositing a transparent electrode on the etched structure (S150)

[0103] A transparent electrode (60) can be deposited on the etched structure, and preferably, the transparent electrode can be deposited on the entire surface of the substrate so as to cover the insulating layer (30), the silicon oxide layer (40), and the LED element.

[0104] The transparent electrode (60) can be separated into a first transparent electrode (62) and a second transparent electrode (64) by etching, which is a subsequent process, and can include a transparent conductive oxide (TCO) material such as ITO (Indium Tin Oxide), FTO (Fluorine-doped Tin Oxide), etc.

[0105] The thickness of the transparent electrode (60) may be 100 to 200 nm, and preferably 125 to 160 nm. By satisfying the thickness of the transparent electrode to 100 to 200 nm, there is an effect of lowering the resistance of the applied current.

[0106] The transparent electrode (60) can be deposited by physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALD).

[0107] Specifically, PVD can be performed by thermal evaporation, electron beam evaporation, plasma laser deposition (PLD), or sputtering.

[0108] CVD can be manufactured by metal organic chemical vapor deposition (MOCVD), atmospheric pressure chemical vapor deposition (APCVD), low pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor deposition (PECVD), high density plasma enhanced chemical vapor deposition (HDPCVD), and atomic level chemical vapor deposition (ALCVD).

[0109] Step of patterning the second photoresist for separating the transparent electrode (S160)

[0110] A second photoresist (70) can be patterned on the transparent electrode to separate the transparent electrode.

[0111] The second photoresist (70) can be applied to both sides of the LED element, excluding the center direction of the LED element, among the upper surfaces of the transparent electrode. In addition, there is no need to perform an etching process to have an inclined surface in a subsequent step, and since the transparent electrode is separated by etching, there is no need to heat treat the second photoresist in this step.

[0112] In S160 of Fig. 2, it is illustrated as a positive PR, but is not limited thereto.

[0113] Step of removing the second photoresist after etching the transparent electrode (S170)

[0114] After the transparent electrodes (60) are separated from each other by etching them with the second photo resist (70), the second photo resist (70) can be removed.

[0115] When etching the transparent electrode (60), wet etching or dry etching can be used.

[0116] In wet etching, an aqueous solution containing hydrogen fluoride (HF) and ammonium fluoride (NH4F) can be used, and preferably, an aqueous solution containing hydrogen fluoride (HF) : ammonium fluoride (NH4F) = 0.5 to 3:10 in a weight ratio can be used. In addition, wet etching can be performed for 5 to 60 seconds, and preferably for 10 to 30 seconds.

[0117] In dry etching, one or more gases among chlorine (Cl2), boron boride (BCL3), carbon tetrafluoride (CF4), fluoroform (CHF3), and argon (Ar) can be used, and can be performed at -5 to 5°C, and preferably, one or more gases among chlorine (Cl2) and boron boride (BCL3) can be used.

[0118] The dry etching time can be performed for 100 to 600 seconds, preferably for 200 to 600 seconds, and more preferably for 400 to 600 seconds.

[0119] By wet etching or dry etching the transparent electrode, excellent uniformity of the etched surface can be achieved.

[0120] The first transparent electrode (62) and the second transparent electrode (64) that are etched and separated can contact the side of the LED element and the silicon oxide layer (40) present on the upper and lower sides of the LED element.

[0121] In this way, the LED assembly from which the second photoresist has been removed can have a structure in which one micro LED element is aligned in one groove, and even in a structure in which the side of the groove has an inclined surface, there is an effect in which the LED element is assembled in a fixed state.

[0122] Additionally, since the silicon oxide layer supports the upper and lower parts of the LED elements, the arrangement of the LED elements is maintained and there is an effect of not being detached even if the groove size increases.

[0123] An LED assembly according to the present invention may include a substrate, a first electrode layer and a second electrode layer spaced apart from each other on the substrate, an insulating layer covering the first electrode layer and the second electrode layer and including a groove in a region between the first electrode layer and the second electrode layer, an LED element aligned in the groove, a silicon oxide layer disposed on an upper portion of the insulating layer and on an upper and lower portion of the LED element, and a first transparent electrode and a second transparent electrode spaced apart from each other so as to surround a side surface of the LED element and the silicon oxide layer.

[0124] At this time, the side of the home may have a slope that slopes outward from the bottom to the top when viewed from the side in a cross-sectional view, and the side of the silicon oxide layer present on the top of the LED element may also have a slope.

[0125] In addition, with respect to the thickness of the silicon oxide layers disposed on the upper and lower portions of the LED element, the thickness of the upper silicon oxide layer may be greater than the thickness of the lower silicon oxide layer. This is because, if the thickness of the upper silicon oxide layer is relatively thick, a sufficient contact area between the LED element and the transparent electrode is secured, which has the effect of lowering the contact resistance.

[0126] Details on each component are the same as those described above in the manufacturing method, so they will be omitted.

[0127] Specific examples of an LED assembly with low contact resistance and a manufacturing method thereof are as follows.

[0128] After applying the silicon oxide solution according to the present invention, observation was performed.

[0129] The silicon oxide solution was heat-treated stepwise at 85°C, 155°C, and 255°C, and then cooled to room temperature. The first photoresist was heat-treated at 110°C for 1 minute using AZ MIR 700 equipment, and then selectively removed using a developer for 40 seconds, followed by heat-treatment at 110°C for 2 minutes.

[0130] The gap between the insulating layer and the LED element was filled by coating the upper surface of the structure with a silicon oxide solution, and it was confirmed that the silicon oxide solution was also coated on the LED element. The thickness of the silicon oxide layer coated on the LED element was measured to be approximately 109 nm.

[0131] Additionally, it was confirmed that the first photoresist was applied and patterned on the coated silicon oxide layer.

[0132] In this way, the LED assembly and its manufacturing method according to the present invention have the effect of lowering contact resistance by securing a contact area between the LED element and the transparent electrode by filling the gap between the insulating layer and the LED element using a silicon oxide solution and fixing the LED element, and then making the side surface of the insulating layer have an inclined surface.

[0133] In addition, by applying a silicon oxide layer during the manufacturing process of the LED assembly, the alignment position of the LED element can be maintained even if the size of the groove of the insulating layer is large, and the occurrence of defects and failures in the LED element can be prevented, resulting in an excellent yield.

[0134] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

Claims

1. (a) A step of preparing a structure including a substrate, a first electrode layer and a second electrode layer spaced apart from each other on the substrate, an insulating layer covering the first electrode layer and the second electrode layer and including a groove in a region between the first electrode layer and the second electrode layer, and an LED element aligned in the groove; (b) a step of coating a silicon oxide solution on the upper surface of the structure to fill the gap between the insulating layer and the LED element; (c) a step of patterning a first photoresist on the coated silicon oxide layer; (d) a step of etching the insulating layer and the silicon oxide layer using the first photoresist, and then removing the first photoresist; (e) a step of depositing a transparent electrode on the etched structure; (f) a step of patterning a second photoresist for separating transparent electrodes on the transparent electrode; and (g) A method for manufacturing an LED assembly, comprising: a step of etching a transparent electrode by the second photoresist, and then removing the second photoresist.

2. In paragraph 1, The above silicon oxide solution is a method for manufacturing an LED assembly comprising a silicate polymer, an organic solvent, and distilled water.

3. In paragraph 1, A method for manufacturing an LED assembly wherein the thickness of the above silicon oxide layer is 100 to 150 nm.

4. In paragraph 1, A method for manufacturing an LED assembly, wherein, in step (b) above, the gap between the insulating layer and the LED element is filled to secure the LED element to the groove.

5. In paragraph 1, In the above step (b), a soft bake step of first heat-treating the coated silicon oxide solution at 80 to 280°C, then second heat-treating and third heat-treating it; and a hard bake step of heat-treating the third heat-treated silicon oxide layer at 410 to 430°C; A method for manufacturing an LED assembly that satisfies the following conditions: first heat treatment temperature (T1) < second heat treatment temperature (T2) < third heat treatment temperature (T3).

6. In paragraph 1, Step (c) above (c1) a step of patterning a first photoresist on the coated silicon oxide layer; and (c2) A method for manufacturing an LED assembly, comprising the step of heat-treating the patterned first photoresist to form an inclined surface on the side of the first photoresist.

7. In paragraph 6, A method for manufacturing an LED assembly by heat treating at 110 to 150°C in the above step (c2).

8. In paragraph 1, Step (d) above (d1) a step of etching the side of the insulating layer, the side of the silicon oxide layer, and the side of the silicon oxide layer present on the upper portion of the LED element so that they have an inclined surface by the first photoresist; and (d2) A method for manufacturing an LED assembly, comprising: a step of removing the first photoresist.

9. In paragraph 1, A method for manufacturing an LED assembly in which, in the step (g) above, the first transparent electrode and the second transparent electrode, which are etched and separated, are in contact with the side surface of the LED element and the silicon oxide layer present on the upper and lower surfaces of the LED element.

10. In paragraph 1, A method for manufacturing an LED assembly in which one micro LED element is aligned in one of the above-mentioned grooves.

11. Substrate; A first electrode layer and a second electrode layer spaced apart from each other on the substrate; An insulating layer covering the first electrode layer and the second electrode layer, and including a groove in the area between the first electrode layer and the second electrode layer; LED elements aligned in the above groove; A silicon oxide layer disposed on the upper part of the insulating layer and on the upper and lower parts of the LED element; and An LED assembly comprising a first transparent electrode and a second transparent electrode spaced apart from each other so as to surround the side surface of the LED element and the silicon oxide layer.

12. In paragraph 11, The side of the above home is an LED assembly having an inclined surface.

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