KR102375861B1 - Ultra-small double LED devices with back-to-back construction and their manufacturing methods and Electrode assembly and manufacturing method of ultra-small double LED with back-to-back structure - Google Patents

Abstract

The back-to-back connected dual micro LEDs of the present invention solve the following problems due to the low polarity arrangement that occurs in the self-assembly and transfer process of the conventional single micro LEDs. can be solved First, since the ultra-small double LED device of the present invention does not require polarity arrangement, it is not necessary to apply a self-assembled voltage asymmetrically. can solve the problem of low luminance of light emission and degradation of efficiency. Third, therefore, the ultra-small double LED device having the back-to-back structure of the present invention can dramatically improve the light-emitting luminance and efficiency of the LED display.

Description

BACKGROUND ART Ultra-small double LED devices with back-to-back construction and their manufacturing methods and Electrode assembly and manufacturing method of ultra-small double LED with back-to-back structure}

The present invention relates to an ultra-small LED device having a novel structure, a manufacturing method thereof, and an ultra-small LED electrode assembly thereof, and more particularly, to a back-to-back-connected ultra-small dual LED of a nano or micro size. It relates to an electrode assembly of an ultra-small double LED device of a back-to-back structure and a method for manufacturing the same, which can effectively produce a device and increase the light emitting luminance and efficiency even when driving the ultra-small double LED device of the back-to-back structure produced by direct current. It relates to an electrode assembly of an ultra-small double LED device having a back-to-back structure of improved characteristics, which is connected without defects such as short circuit, and exhibits very excellent light emitting characteristics in DC driving even without polar ordering, and a method for manufacturing the same.

Currently, studies are actively conducted to develop a light emitting diode (LED) with high light conversion efficiency by improving the growth structure of the nitride-based semiconductor and the manufacturing process of the grown thin film using a nitride-based semiconductor with a large bandgap. is in progress In 1992, Nakamura et al. of Nichia Corporation of Japan succeeded in manufacturing a high-quality single-crystal GaN nitride semiconductor by applying a low-temperature GaN compound buffer layer, and the development has been actively carried out. The LED is a semiconductor device having a structure in which an n-type semiconductor crystal in which a plurality of carriers are electrons and a p-type semiconductor crystal in which a plurality of carriers are holes by using the characteristics of a compound semiconductor are bonded to each other. It is a kind of optical device that can convert light into light of a specific wavelength band.

In relation to such an LED, Korean Patent Application Laid-Open No. 2009-0121743 discloses a method for manufacturing a light emitting diode and a light emitting diode manufactured by the method. Existing LED devices are formed by depositing p-semiconductor layers, quantum well layers, and n-semiconductor layers of group III-V materials on a sapphire substrate with a size of 2 to 8 inches by metal organic chemical vapor deposition (MOCVD), followed by cutting. Through various post-processes such as , wiring, packaging, etc., it is manufactured into various types of devices. Since these LED devices have very high light conversion efficiency, energy consumption is very low, the life of the device is semi-permanent, and it is environmentally friendly, traffic lights, mobile phones, automobile headlights, outdoor electric signs, LCD BLU (back light unit), and indoor and outdoor lighting It is being applied in many fields, such as, and active research on it is continuing at home and abroad.

Among these series of studies, studies using LED devices in which the size of LED devices are manufactured in nano or micro units are being actively conducted. In particular, research for using such a miniature LED device for lighting or a display is continuing.

In particular, in order to realize an LED display, which is predicted as a next-generation display, a bottom-up method, 2) a top-down method, and 3) a method using these methods are being researched and developed.

First, the bottom-up method is a method of directly growing a group III-V thin film and a nanorod LED device on a patterned pixel position on a large-area glass substrate for an actual display. According to what has been known through many studies so far, it is known that a direct deposition process on a large substrate, such as a display-grade size for TV, is not possible due to facility reasons using the MOCVD method for growing a III-V group thin film. In addition, it is known that it is also very difficult crystallographically to grow a group III-V thin film and nanorod heterojunction LED device with high crystallinity/high efficiency on a transparent electrode having a pattern formed on a transparent amorphous glass substrate. Due to such technical limitations, there has been hardly any attempt to implement a full-color TV or monitor-level display by directly growing LED elements on a large-area glass substrate, except for small elements.

Another approach being pursued by many researchers to realize LED display is a bottom-up method 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, removing a part, and rearranging it on an electrode patterned with a pixel in a bottom-up method. However, the nanorod LED manufactured by the bottom-up method has a problem in that the luminous efficiency is low compared to the conventional thin film LED grown on a wafer. In addition, in order to arrange the nanorod LED device grown in the bottom-up method on the electrode by the bottom-up method self-assembly method, it is essential to obtain a nanorod device having a uniform size. However, there is very little possibility of mass production of nanorod LED devices having uniform size and characteristics that are easy for self-assembly by using a nanorod growth method such as the well-known Vapor-Liquid-Solid (VLS) method.

As another method, there is a top-down method in which a high-efficiency LED element is cut to realize an LED display. In general, this method is a method of realizing a display in a one-to-one correspondence method by arranging one micro LED element manufactured in a top-down method at the sub-pixel position of a large-area glass substrate. Specifically, in the case of a micro-sized LED display, each micro LED manufactured in the top-down method was manufactured as each sub-pixel, and a small micro LED display was developed. In this case, since the LED device is grown on a sapphire substrate and patterned to a micro size to manufacture the micro LED device and then the electrodes are wired, a micro LED display smaller than the size of the wafer substrate is realized. When this method is used, there is no problem in efficiency, but it is impossible to implement a large-area LED display due to the limitations of the substrate size and manufacturing process.

As a result, there is a limit to realizing a mass-produced, high-efficiency/large-area LED display device with the conventional top-down or bottom-up method of manufacturing ultra-small micro/nano LED devices.

Furthermore, when the miniature LED device manufactured by the conventional method is placed in the sub-pixel (pixel position) of the LED display substrate, the size of the LED device is too small, so the purpose of the micro/nano LED device on the sub-pixel of the LED display There was a problem that it could not be placed and mounted in one electrode area.

A method of manufacturing an ultra-small single LED device according to the prior art for solving the above-described problems includes: 1) sequentially forming a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer on a substrate; 2) etching the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer so that the diameter of the LED device has a nano or micro size; and 3) forming an insulating film on outer peripheral surfaces of the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer, and removing the substrate. (Patent Publication 10-2012-0122159)

The issues that are continuously attracting attention in the production and application research of these ultra-small LED devices are the electrodes that can apply power to the ultra-small LED devices, the arrangement of electrodes to minimize the space occupied by the electrodes, and the ultra-small LEDs on the arranged electrodes. There are things about how to properly mount the .

Among them, in the issue of how to mount the ultra-small single-type LED device on the arranged electrode, the problem that it is very difficult to place and mount the ultra-small LED device on the arrangement electrode as intended due to the limitation of the size of the ultra-small LED device still exists. there is. This is because, since ultra-small LED devices are nano-scale or micro-scale, it is impossible to arrange and mount micro-sized devices one by one in the target electrode area with a person or general equipment.

In addition, even if the micro LED device is mounted on the target electrode area, it is very difficult to control the number of micro LED devices included in the unit electrode area, the position of the micro LED device, etc. There is a difficult problem.

In order to overcome this, an assembly in which the bidirectional, non-polar axial ordering of the ultra-small LED device is increased by contacting a solution containing the micro-LED device to the micro-electrode line and applying a symmetrical AC power supply A manufacturing method and a miniature LED electrode assembly were implemented. (Republic of Korea Patent Publication No. 10-1490758) However, in the case of applying direct current (DC) as a driving power, in the miniature LED electrode assembly implemented with this technology, the number of miniature LED elements that do not emit light is almost half (50%) ), making it difficult to obtain the desired luminance.

This is because of the rectifying device characteristics of the ultra-small single type LED device. The current flow in the diode device is determined according to the device structure. For example, in the case of an LED in which a p-type semiconductor and an n-type semiconductor are junctioned, a (+) power is connected to the p-type semiconductor, and a (-) power is connected to the n-type semiconductor. When power is connected, current may flow while electrons injected into the n-type semiconductor move toward the p-type semiconductor, and the electrons may emit light while recombination with holes. However, if the (-) power is connected to the p-type semiconductor and the (+) power is connected to the n-type semiconductor, no current flows in the LED and no light is emitted.

For this reason, when the ultra-small single LED elements are arranged in the direction opposite to the direction of the current flow between the DC driving electrodes, the arranged ultra-small LED electrode assembly does not emit light in response to the application of the DC driving power, so There is a problem in that the light emission luminance is significantly lowered. In order to solve this problem, there is a limit in the selection of a power source to which an alternating current (AC) must be applied as a driving power.

In contrast, unidirectional polar ordering of the ultra-small single-type LED device has an asymmetric waveform to the micro-electrode line, and the magnitude of the upper peak voltage is different from that of the lower peak voltage by applying an asymmetric assembly voltage different from that of the lower peak voltage. ), a manufacturing method for implementing an increased assembly and an ultra-small LED electrode assembly were implemented. (Korea Registered Patent Publication No. 10-1730927)

In addition, a manufacturing method for implementing an assembly in which the arrangement of ultra-small single-type LED elements is increased by applying AC power and installing an assembly groove and a method for manufacturing an ultra-small LED electrode assembly have been proposed (Republic of Korea Patent Publication No. 10-2019) -0131263) This is also insufficient to realize high polarity alignment.

Accordingly, there is an urgent need to research and develop a more improved ultra-small LED electrode assembly of a micro/nano LED device.

The present invention has been devised to solve the above problems,

The first problem to be solved by the present invention is a method of manufacturing a new type of ultra-small micro/nano LED device that can solve the problem of low luminance and efficiency degradation due to the low polarity of the LED device in the transfer process of the existing ultra-small single type LED device is to provide

The second problem to be solved by the present invention is to provide a new micro/nano LED electrode assembly capable of operating even when the micro/nano LED device of the present invention is placed upside down on a sub-pixel (pixel position) of an LED display, and a method for manufacturing the same will provide

Another object of the present invention is to provide an electrode assembly for a novel ultra-small micro/nano LED that exhibits sufficient light emitting luminance characteristics with a DC driving power source and a method for manufacturing the same.

In addition, another object of the present invention is to provide an electrode assembly of a micro/nano LED having improved luminance and efficiency characteristics more than that of a conventional electrode assembly of an ultra-small single LED, and a method of manufacturing the same.

Another object of the present invention is to provide a light source capable of exhibiting excellent luminance characteristics through the electrode assembly of a micro/nano LED according to the present invention and a display having the same.

In addition, the present invention can express excellent luminance characteristics through the electrode assembly of the ultra-small micro/nano LED according to the present invention, and at the same time, a display with improved intensity of light for a specific color and uniform luminance can be expressed. Another object is to provide a full-color LED display with

A method of manufacturing an ultra-small micro/nano LED device according to an embodiment of the present invention for solving the above problems is 1) on a substrate

A first LED layer is sequentially formed, including a first conductive semiconductor layer, a first active layer, and a second conductive semiconductor layer,

The second LED layer is formed in reverse order by further including a third conductive semiconductor layer, a second active layer and a fourth conductive semiconductor layer successively on top of it,

sequentially forming a double LED device layer having a back-to-back structure;

2) The diameter of the double LED device of the back-to-back structure including the first conductive semiconductor layer, the first active layer, the second conductive semiconductor layer, the third conductive semiconductor layer, the second active layer, and the fourth conductive semiconductor layer is nano or etching to have a micro size; and

3) removing the substrate; including

It includes the step of manufacturing an ultra-small double LED device of the back-to-back structure.

According to a preferred embodiment of the present invention, the first conductive semiconductor layer and the fourth conductive semiconductor layer include at least one n-type semiconductor layer, and the second conductive semiconductor layer and the third conductive semiconductor layer include at least one It may include a p-type semiconductor layer.

According to another preferred embodiment of the present invention, the first conductive semiconductor layer and the fourth conductive semiconductor layer include at least one p-type semiconductor layer, and the second conductive semiconductor layer and the third conductive semiconductor layer are at least It may include one n-type semiconductor layer.

According to another preferred embodiment of the present invention, the step 2) is;

2-1) sequentially forming a second electrode layer, an insulating layer, and a metal mask layer on the fourth 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) The first conductive semiconductor layer, the first active layer, the second conductive semiconductor layer, the third conductive semiconductor layer, the second active layer and the fourth conductive semiconductor layer are dry or wet at nano or micro intervals depending on the pattern. etching;

and 2-4) removing the insulating layer, the metal mask layer, and the polymer layer.

According to another preferred embodiment of the present invention, the step 2) is;

2-5) forming a second electrode layer, an insulating layer, and a metal mask layer on the fourth conductive semiconductor layer;

2-6) forming a nanosphere or microsphere monolayer on the metal mask layer and performing self-assembly;

2-7) The first conductive semiconductor layer, the first active layer, the second conductive semiconductor layer, the third conductive semiconductor layer, the second active layer and the fourth conductive semiconductor layer are dry or wet at nano or micro intervals depending on the pattern. etching;

and 2-8) by removing the insulating layer, the metal mask layer, and the nanosphere or microsphere monolayer film

It may include manufacturing a back-to-back ultra-small double LED device.

According to another preferred embodiment of the present invention, the nanospheres or microspheres may be made of a polystyrene material.

According to another preferred embodiment of the present invention, the step 3) is;

3-1) forming a support film on the second electrode layer;

3-2) forming an insulating film on the outer peripheral surface including the first active layer and the second active layer;

3-3) removing the substrate;

3-4) forming a first electrode layer under the first conductive semiconductor layer;

and 3-5) removing the support film to manufacture a plurality of back-to-back ultra-small double LED devices.

In order to achieve the first object of the present invention, a first conductive semiconductor layer; a first active layer formed on the first conductive semiconductor layer; A second conductive semiconductor layer formed on the first active layer, a third conductive semiconductor layer formed on the second conductive semiconductor layer, a second active layer formed on the third conductive semiconductor layer, and a fourth formed on the second active layer A conductive semiconductor layer; including a micro- or nano-sized semiconductor light emitting device comprising a; The semiconductor light emitting device provides an ultra-small double LED device having a back-to-back structure including an insulating film coated on a portion of an outer circumferential surface.

According to a preferred embodiment of the present invention, it may include a hydrophobic film coated on the insulating film.

According to another preferred embodiment of the present invention, a first electrode layer formed under the first conductive semiconductor layer; and a second electrode layer formed on the fourth conductive semiconductor layer.

In order to achieve the second object of the present invention, the method for manufacturing an electrode assembly of an ultra-small double LED having a back-to-back structure according to an embodiment of the present invention includes (1) a first mounting electrode and a second mounting electrode formed to be spaced apart from the first mounting electrode Contacting a solution containing a plurality of back-to-back structure ultra-small double LED elements on the upper portion of the electrode line including the electrode;

(2) applying a power supply having an assembly voltage of 1.0 V or higher through the electrode line to generate electric and torque forces in the plurality of back-to-back structured ultra-small double LED devices to generate an electric field It includes; by moving and rotating so as to arrange non-polarity in the direction, the ends of the plurality of back-to-back structures of the ultra-small double LED elements are in contact with the first mounting electrode and the second mounting electrode with non-polar arrangement.

The method for manufacturing an electrode assembly of an ultra-small double LED having a back-to-back structure, which is an embodiment of the present invention,

The assembly voltage is a symmetric voltage.

In addition, in the step (1), it characterized in that it further comprises a third electrode formed to be spaced apart between the first mounting electrode and the second mounting electrode, the center of the plurality of back-to-back structure of the ultra-small double LED element, that is, the first A portion of the second conductive semiconductor layer and the third conductive semiconductor layer may be in contact with the third electrode.

In addition, after performing step (2),

(3) heat-treating the plurality of back-to-back ultra-small double LED devices arranged on the electrode line at 300° C. to 1,000° C. for 0.5 to 10 minutes; may further include.

In addition, in step (1), an insulating layer may be further included on the first and second mounting electrodes.

According to an embodiment of the present invention, there is provided an ultra-small double LED electrode assembly having a back-to-back structure, comprising: an electrode line including a first mounting electrode and a second mounting electrode spaced apart from each other; and a back-to-back ultra-small double LED device having one end in contact with the first mounting electrode, the other end in contact with the second mounting electrode, and improved nonpolar arrangement by applying an assembly voltage.

In addition, it characterized in that it further comprises a third electrode between the first mounting electrode and the second mounting electrode, the center of the plurality of back-to-back micro-sized double LED device, that is, the second conductive semiconductor layer and the third conductive semiconductor layer A portion of may be in contact with the third electrode.

In addition, the ultra-small double LED device of the back-to-back structure, a first active layer; It may include a second conductive semiconductor layer formed on the first active layer, a third conductive semiconductor layer formed thereon, a second active layer formed thereon, and a fourth conductive semiconductor layer formed thereon.

Here, the back-to-back structure of the ultra-small double LED device having a length of 100 nm to 30 μm may be used.

Furthermore, the ultra-small double LED device having the back-to-back structure may use one or more mounted per unit light emitting pixel.

An ultra-small double LED electrode assembly having a back-to-back structure, which is an embodiment of the present invention,

an electrode line including a first mounting electrode and a second mounting electrode spaced apart from each other; and

Including a first conductive semiconductor and a fourth conductive semiconductor, one end is in contact with the first mounting electrode, the other end is in contact with the second mounting electrode, and has a back-to-back structure with improved non-polarity arrangement by applying a symmetric assembly voltage. a double LED element;

Among the total number of ultra-small double LED devices of the back-to-back structure, 80% or more of the number of non-polar arrayed ultra-small LED devices in which the first conductive semiconductor or the fourth conductive semiconductor is in contact with the first mounting electrode may be used.

In addition, the first conductive semiconductor or the fourth conductive semiconductor is in contact with the first mounting electrode among the total number of ultra-small double LED devices of the back-to-back structure, and the back-to-back structure of the ultra-small double LED device is non-polar by applying a symmetric assembly voltage. The number may be 90% or more.

In addition, it characterized in that it further comprises a third electrode formed spaced apart between the first mounting electrode and the second mounting electrode, the center of the plurality of back-to-back ultra-small double LED device, that is, the second conductive semiconductor layer and the third A portion of the conductive semiconductor layer may be in contact with the third electrode.

The light source according to an embodiment of the present invention may include a back-to-back ultra-small double LED electrode assembly.

The display according to an embodiment of the present invention may include a back-to-back ultra-small double LED electrode assembly.

Hereinafter, the terms used in the present invention will be described.

In the description of the embodiment according to the present invention, "mounted electrode" and "third electrode" refer to electrodes that are in direct or indirect contact with both ends of a back-to-back micro-dual LED device, and a back-to-back micro-dual LED In order to drive the electrode assembly, a power supply may be directly connected to the mounting electrode and the third electrode, or an additional electrode, an address electrode or a gate electrode, or an insulating layer may be further included to be connected to the power supply.

In the description of an embodiment according to the present invention, each layer, region, pattern or structure is referred to as “on”, “above”, “above”, “under” the substrate, each layer, region, or patterns. In cases where it is described as being formed under “lower”, “lower”, “on”, “upper”, “upper”, “under”, “lower”, “lower” are “directly” and the meaning of "indirectly".

In the description of the embodiment according to the present invention, the meaning of "contact" includes all cases in which the components 1 and 2 are directly structurally connected or indirectly structurally connected including the component 3 . For example, the meaning of "the first conductive semiconductor in contact with the first mounting electrode" is not only when the first conductive semiconductor is directly structurally connected to the first mounting electrode, but also when an electrode layer is formed on the first conductive semiconductor, and the electrode layer and a case in which the first conductive semiconductor is indirectly structurally connected to the first mounting electrode as the first mounting electrode is structurally connected. On the other hand, the structural connection does not mean an electrical connection state related to whether or not the ultra-small double LED element of the back-to-back structure emits light when driving power is applied to the electrode line, and includes all states of physical contact even if not electrically connected.

In the description of the embodiment according to the present invention, each layer (film), region, pattern or structure is formed “on” or “under” each layer (film), region, pattern or substrate, each layer (film), region, or patterns. Where described as being, "on" and "under" include both "directly" and "indirectly". In addition, the criteria for above or below each layer will be described with reference to the drawings.

The back-to-back structure of the ultra-small dual LED device of the present invention can solve the problem of low light emitting luminance and efficiency degradation during direct current driving due to the low polarity arrangement problem that occurs in the self-assembly process of the conventional single ultra-small LED device. there is.

In addition, in the back-to-back structure of the ultra-small double LED device of the present invention, low polarity alignment is not a problem, and application of an asymmetric assembly voltage for inducing polarity alignment is not required, and sub-pixel (pixel position) of the LED display is not required. ) on the back-to-back structure of the ultra-small double LED elements arranged upside down can operate regardless of this, so it is possible to dramatically improve the DC driving luminance and efficiency of the LED display.

According to the present invention, as the non-polar arrangement of the back-to-back ultra-small double LED device in the electrode line is increased, even if the back-to-back ultra-small double LED device is disposed upside down on the micro electrode, excellent light emitting luminance can be expressed. In addition, it can be advantageous in terms of productivity and production cost because it is possible to arrange a small double LED device having a back-to-back structure even with a non-polar assembly voltage.

In addition, sufficient luminance characteristics can be expressed even through a DC driving power supply by solving the limitation in driving power selection of the ultra-small double LED electrode assembly having a back-to-back structure. That is, in the case of the ultra-small double LED electrode assembly having a back-to-back structure manufactured through an embodiment of the present invention, a DC voltage is applied as a driving power source between the first and third electrodes and between the second and third electrodes. When this is done, the intensity of light emission of the ultra-small double LED device having a back-to-back structure can be significantly increased.

Therefore, it can be a miniature double LED electrode assembly with a back-to-back structure more suitable for various electronic components and devices that use DC power as a driving power source at the same time as DC power is more efficient than AC power as a driving power, and a simple DC driving circuit can be used for productivity , it may be more advantageous in terms of production cost.

Furthermore, the intensity of the light corresponding to the light emission wavelength of the ultra-small double LED of the back-to-back structure is further improved, and even when converted to a color of another wavelength using this, it can be widely used in various lighting equipment with improved intensity of the converted color light. , can be applied to displays, various parts, and electronic devices in which LED devices are used.

1 is a cross-sectional view showing a step (left) of forming an ultra-small double LED device layer of a back-to-back structure according to an embodiment of the present invention and a step (right) of forming a micro-single LED device layer according to an embodiment of the present invention; am.
2 is a cross-sectional view illustrating a step of forming a second electrode layer, an insulating layer, and a metal mask layer on the fourth conductive semiconductor layer of the present invention.
3 is a cross-sectional view showing the step of forming a nanosphere or microsphere monolayer on the metal mask layer of the present invention.
4 is a cross-sectional view showing an ashing step of the nanosphere or microsphere monolayer of the present invention.
5 is a cross-sectional view showing an etching step of the present invention.
6 is a cross-sectional view showing the step of removing the sphere monolayer film, the metal mask layer, and the insulating layer of the present invention.
7 is a cross-sectional view showing the step of attaching the support film on the second electrode layer of the present invention.
8 is a cross-sectional view showing the step of coating the outer peripheral surface of the ultra-small dual LED device of the back-to-back structure of the present invention with an insulating film.
9 is a cross-sectional view showing the step of coating the insulating film formed on the outer peripheral surface of the ultra-small double LED device of the present invention with a hydrophobic film.
10 is a cross-sectional view illustrating a step of removing the substrate formed under the first conductive semiconductor layer of the ultra-small dual LED device of the back-to-back structure of the present invention.
11 is a cross-sectional view illustrating a step of depositing an electrode under the first conductive semiconductor layer from which the substrate of the present invention is removed.
12 is a cross-sectional view showing the step of manufacturing the ultra-small double LED devices of the independent back-to-back structure by removing the support film of the present invention.
13 is a perspective view and an electrical symbol showing a miniature dual LED device having a back-to-back structure of the present invention.
14 is a diagram of a back-to-back structure micro-dual LED electrode assembly according to an embodiment of the present invention. FIG. 14 is a perspective view of an electrode assembly of a back-to-back micro double LED electrode assembly having an improved nonpolar arrangement.
15A is a view of a miniature single type LED electrode assembly manufactured by applying a symmetrical assembly power source in a conventional method, and shows a perspective view and an electrical symbol of the miniature single type LED electrode assembly having a low polarity arrangement.
15B is a view of a miniature single LED electrode assembly manufactured by applying asymmetric assembly power in a conventional method, and is a perspective view of a miniature single LED electrode assembly having a low polarity arrangement.
16 is a schematic diagram of a manufacturing process of a back-to-back structure of an ultra-small double LED electrode assembly according to an embodiment of the present invention.
17 is a schematic diagram showing the electric force and torque force between the electric field by the assembly voltage applied between the mounting electrodes and the miniature LED element;
17A is a schematic diagram (left) before power is applied to the mounting electrode of the prior art and a schematic diagram showing the electric force and torque force between the electric field by the symmetric assembly power applied between the mounting electrodes and the ultra-small single type LED element (right). ,
17b is a schematic diagram showing the electric force and torque force between the electric field and the ultra-small single type LED element by the asymmetric assembly power applied between the mounting electrodes of the prior art;
17c is a schematic view showing the electric force and torque force between the electric field by the symmetric assembly power applied between the mounting electrodes of the present invention and the ultra-small double LED element of the back-to-back structure.
17D is a back-to-back structure micro-dual LED device mounted in a non-polar, non-polar arrangement by an electric field and a torque force between the miniature double LED device of the back-to-back structure and the electric field by the symmetric assembly power applied between the mounting electrodes of the present invention. is a schematic diagram showing

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are added to the same or similar elements throughout the specification.

As described above, the electrode assembly of the ultra-small single-type LED device manufactured by the conventional assembly voltage application method is highly likely to have problems of low light emitting luminance and reduced efficiency when driving a DC voltage due to low polarity arrangement. In addition, in the case of a conventional ultra-small single-type LED device, an agglomerate may be formed by mutual cohesion due to polarity between the micro devices, which may cause a number of defects in the pixel patterning process. Therefore, there is a limit to realizing a mass-produced, high-efficiency/large-area LED display device only with the existing ultra-small single-type LED device.

Furthermore, in the case of locating the existing ultra-small single type LED device in the sub-pixel (pixel position) of the LED display substrate by the conventional assembly voltage application method, the polarity orientation of the ultra-small single type LED device is too small, so that on the sub-pixel of the LED display There was a problem in that the existing ultra-small single-type LED device was placed upside down.

In order to solve these problems, accurately position the LED elements in the sub-pixels of the LED display substrate, and increase the light emitting luminance and efficiency of each independent element, it is urgently required to manufacture a new structure of micro/nano LED elements and a method for arranging them. there is.

Accordingly, in the present invention, 1) a first LED layer is sequentially formed including a first conductive semiconductor layer, a first active layer and a second conductive semiconductor layer on a substrate,

The second LED layer is formed in reverse order by further including a third conductive semiconductor layer, a second active layer and a fourth conductive semiconductor layer successively on top of it,

sequentially forming a double LED device layer having a back-to-back structure;

2) The diameter of the double LED device of the back-to-back structure including the first conductive semiconductor layer, the first active layer, the second conductive semiconductor layer, the third conductive semiconductor layer, the second active layer and the fourth conductive semiconductor layer is nano or micro size etching to have and

3) removing the substrate; including

A method for manufacturing an ultra-small double LED device having a back-to-back structure was provided to solve the above-mentioned problem.

First, as step 1), a first LED layer is sequentially formed on a substrate including a first conductive semiconductor layer, a first active layer, and a second conductive semiconductor layer, and a third conductive semiconductor layer, a second active layer, and Further including the fourth conductive semiconductor layer is sequentially formed including the second LED layer in reverse order.

Specifically, FIG. 1 is a cross-sectional view showing a step of forming a back-to-back ultra-small double LED device layer according to an embodiment of the present invention. A first conductive semiconductor layer 11, a first active layer 12, a first conductive semiconductor layer 11 on a substrate 10, It includes a second conductive semiconductor layer 13 , a third conductive semiconductor layer 242 , a second active layer 241 , and a fourth conductive semiconductor layer 240 .

The substrate 10 may include a sapphire substrate (Al ₂ 0 ₃ ) and a transparent substrate such as glass. In addition, the substrate 10 may be selected from the group consisting of GaN, SiC, ZnO, Si, GaP and GaAs, a conductive substrate, and the like. Hereinafter, the embodiment will be described as an example of a sapphire substrate. A concave-convex pattern may be formed on the upper surface of the substrate 10 .

A nitride semiconductor is grown on the substrate 10 , and the growth equipment is an electron beam evaporator, physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma laser deposition (PLD), and a dual-type thermal evaporator. ) may be formed by sputtering, metal organic chemical vapor deposition (MOCVD), or the like, but is not limited to such equipment.

A buffer layer (not shown) and/or an undoped conductor layer (not shown) may be formed on the substrate 10 . The buffer layer is a layer for reducing a difference in lattice constant with the substrate 10 and may be formed of at least one of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. The undoped semiconductor layer may be implemented as an undoped GaN layer, and functions as a substrate on which a nitride semiconductor is grown. Only one of the buffer layer and the undoped semiconductor layer may be formed, or both layers may or may not be formed.

According to a preferred embodiment of the present invention, the thickness of the substrate may be 400 to 500 μm, but is not limited thereto.

A 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, wherein the n-type semiconductor layer is In _x Al _y Ga _1-xy N (0 ≤ x ≤ 1, 0 ≤ y ≤ 1). , 0≤x+y≤1) of a semiconductor material having a composition formula, for example, InAlGaN, GaN, AlGaN, InGaN, AlN, InN, etc., any one or more may be selected, and the first conductive dopant (eg, Si, Ge, Sn) etc.) may be doped. According to a preferred embodiment of the present invention, the thickness of the first conductive semiconductor layer may be 1.5 to 5 μm, but is not limited thereto.

The first active layer 12 is formed on the first conductive semiconductor layer 11 and may have a single or multiple quantum well structure. A cladding layer (not shown) doped with a conductive dopant may be formed above and/or below the first active layer 12 , and the clad layer doped with the conductive dopant may be implemented as an AlGaN layer or an InAlGaN layer. there is. Of course, other materials such as AlGaN and AlInGaN may also be used as the first active layer 12 . In the first active layer 12 , when an electric field is applied, light is generated by bonding of electron-hole pairs. According to a preferred embodiment of the present invention, the thickness of the first active layer may be 0.05 ~ 0.25 ㎛, but is not limited thereto.

A second conductive semiconductor layer 13 is formed on the first active layer 12, and the second conductive semiconductor layer 13 may be implemented as at least one p-type semiconductor layer, wherein the p-type semiconductor layer includes In a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ x + y ≤ 1), for example, InAlGaN, GaN, AlGaN, InGaN, AlN, InN, etc. Any one or more may be selected, and a second conductive dopant (eg, Mg) may be doped. Here, the light emitting structure includes the first conductive semiconductor layer 11, the first active layer 12, and the second conductive semiconductor layer 13 as a minimum component, and different phosphors above and below each layer. It may further include a layer, an active layer, 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.

A third conductive semiconductor layer 242 is formed on the second conductive semiconductor layer 13 , and the third conductive semiconductor layer 242 may be implemented as at least one p-type semiconductor layer. The layer is made of a semiconductor material having a compositional formula of In _x Al _y Ga _1-xy N (0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ x+y ≤ 1), for example, InAlGaN, GaN, AlGaN, InGaN, AlN, Any one or more of InN may be selected, and a second conductive dopant (eg, Mg) may be doped.

According to a preferred embodiment of the present invention, the thickness of the third conductive semiconductor layer may be 0.08 to 0.25 μm, but is not limited thereto.

According to a preferred embodiment of the present invention, the third conductive semiconductor layer may have the same configuration as the second conductive semiconductor layer 13, but is not limited thereto.

In addition, according to a preferred embodiment of the present invention, the second conductive semiconductor layer 13 may perform the role of the third conductive semiconductor layer instead, so that, if necessary, the formation of the third conductive semiconductor layer is may be omitted, but is not limited thereto.

In addition, according to a preferred embodiment of the present invention, between the third conductive semiconductor layer and the second conductive semiconductor layer 13, if necessary, an additional conductive semiconductor layer for adjusting the device length may be formed. However, the present invention is not limited thereto.

The second active layer 241 is formed on the third conductive semiconductor layer 242 and may have a single or multiple quantum well structure. A cladding layer (not shown) doped with a conductive dopant may be formed above and/or below the second active layer 241 , and the clad layer doped with the conductive dopant may be implemented as an AlGaN layer or an InAlGaN layer. there is. Of course, other materials such as AlGaN and AlInGaN may also be used as the second active layer 241 . In the second active layer 241 , when an electric field is applied, light is generated by bonding of electron-hole pairs. According to a preferred embodiment of the present invention, the thickness of the second active layer may be 0.05 ~ 0.25 ㎛, but is not limited thereto.

According to a preferred embodiment of the present invention, the second active layer may have the same configuration as the first active layer 12, but is not limited thereto.

A fourth conductive semiconductor layer 240 is formed on the second active layer 241 . The fourth conductive semiconductor layer 240 may include, for example, an n-type semiconductor layer, wherein the n-type semiconductor layer is In _x Al _y Ga _1-xy N (0 ≤ x ≤ 1, 0 ≤ y ≤ 1). , 0≤x+y≤1) may be selected from any one or more semiconductor materials, for example, InAlGaN, GaN, AlGaN, InGaN, AlN, InN, and the like, and a fourth conductive dopant (eg, Si, Ge, Sn). etc.) may be doped. According to a preferred embodiment of the present invention, the thickness of the fourth conductive semiconductor layer may be 1.5 to 5 μm, but is not limited thereto.

According to a preferred embodiment of the present invention, the fourth conductive semiconductor layer may have the same configuration as the first conductive semiconductor layer 11, but is not limited thereto.

Here, the light emitting structure includes the first conductive semiconductor layer 11 , the first active layer 12 , the second conductive semiconductor layer 13 , the third conductive semiconductor layer 242 , and the second active layer 241 . ), including the fourth conductive semiconductor layer 240 as a minimum component, and may further include other phosphor layers, active layers, semiconductor layers and/or electrode layers above/under each layer.

In addition, since the light emission of the ultra-small double LED having the back-to-back structure is not limited to blue, there is no limitation in using a different type of group III-V semiconductor material as the semiconductor layer when the emission color is different. In addition, the positions of the first active layer and the second active layer may be variously positioned depending on the type of LED. Since the light color of the ultra-small LED device is not limited to blue, there is no limitation in using different types of III-V semiconductor materials as the first active layer and the second active layer when the emission color is different.

Next, step 2) includes the first conductive semiconductor layer, the first active layer, the second conductive semiconductor layer, the third conductive semiconductor layer, the second active layer, and the fourth conductive semiconductor layer so that the diameter of the LED device is nano- or micro-sized. etch to have 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 fourth 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 at nano or micro intervals depending on the pattern, including the first conductive semiconductor layer, the first active layer, the second conductive semiconductor layer, the third conductive semiconductor layer, the second active layer and the fourth conductive semiconductor layer etching; and

2-8) may include removing the insulating layer, the metal mask layer, and the monolayer film.

Specifically, FIG. 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 fourth conductive semiconductor 240 layer of the present invention. First, the second electrode layer 20 may use a metal or a metal oxide used in a typical LED device, preferably Cr, Ti, Al, Au, Ni, ITO, and oxides or alloys thereof, etc.

It may be used alone or in combination, 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.

The insulating layer 21 formed on the second electrode layer 20 includes a second electrode layer, a fourth conductive semiconductor layer, a second active layer, a third conductive semiconductor layer, a second conductive semiconductor layer, a first active layer, and a first conductive layer. It may serve as a mask for continuous etching of the semiconductor layer, and may use an oxide or nitride, and as a representative example, silicon oxide (SiO ₂ ) or silicon nitride (SiN) may be used, but is not limited thereto. .

According to a preferred embodiment of the present invention, the thickness of the insulating layer may be 0.5 to 1.5 μm, but is not limited thereto.

The metal mask layer 22 formed on the insulating layer 21 serves as a mask layer for etching, and a commonly used metal may be used. As a representative example, a 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.

3 is a cross-sectional view showing the step of forming the nanosphere or microsphere monolayer film 30 on the metal mask layer 22 of the present invention. Specifically, the nanosphere or microsphere monolayer film is formed to serve as a mask for the etching of the metal mask layer 22, and the method for forming the sphere particles may use the monolayer self-assembly characteristics of the spheres. The diameter of the sphere particles may be selectively used according to the desired diameter of the ultra-small double LED device having a back-to-back structure to be finally produced, and polystyrene spheres, silica spheres, etc. having a diameter of preferably 50 to 3000 nm may be used, but not limited thereto. does not

Figure 4 is a cross-sectional view showing the ashing (ashing) step of the nanosphere or microsphere monolayer 30 of the present invention, the sphere particles are spaced apart. It can be achieved through the ashing process of a conventional sphere monolayer film, and preferably, the ashing process can be performed through oxygen (O ₂ )-based reactive ion ashing (reactive ion ashing) and plasma ashing (plasma ashing).

5 is a cross-sectional view showing the etching step of the present invention, specifically, a process of forming a hole by etching between the sphere particles spaced apart through the ashing process in FIG. In this case, the portion where the sphere particles 30 are formed is not etched, and the spaced space between the sphere particles and the sphere particles is etched to form a hole. The hole may be selectively formed from the metal mask layer 22 to the top of the substrate 10 . As the etching process, a dry etching method such as reactive ion etching (RIE) or inductively coupled plasma reactive ion etching (ICP-RIE) may be used.

Unlike the wet etching method, the dry etching method is suitable for forming such a pattern because one-way etching is possible. That is, in the wet etching method, isotropic etching is performed and etching is performed in all directions. However, in the dry etching method, etching is possible mainly in the depth direction to form a hole, so that the size and spacing of the hole can be adjusted. It can be formed into any desired pattern.

In this case, when using the RIE or ICP-RIE method, Cl ₂ , O ₂ , etc. may be used as an etching gas capable of etching the metal mask.

The spacing (A) of the LED devices manufactured through the etching process is identical to the diameter of the sphere particles 30, and in this case, the spacing (A) of the LED devices may be in nanometers or micrometers, and more preferably may be 50 to 3000 nm.

6 is a step of removing the sphere particles 30, the metal mask layer 22 and the insulating layer 21 after the etching process, and the removal process may be performed through a conventional wet etching or dry etching method, but is limited thereto. and can be removed through a conventional removal method.

According to another embodiment of the present invention, the step 2) is;

2-1) 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) The first conductive semiconductor layer, the first active layer, the second conductive semiconductor layer, the third conductive semiconductor layer, the second active layer and the fourth conductive semiconductor layer are dry or wet at nano or micro intervals depending on the pattern. etching; and

2-4) may include removing the insulating layer, the metal mask layer, and the polymer layer.

Specifically, after forming a second electrode layer, an insulating layer, and a metal mask layer on the fourth conductive semiconductor layer, a conventional polymer layer that can be used in conventional lithography is formed on the metal mask layer, and photolithography is performed on the polymer layer. , e-beam lithography, or nanoimprint lithography, after forming a pattern at nano or micro spacing, dry or wet etching, and removing the insulating layer, the metal mask layer and the polymer layer.

Next, as a step 3), including the step of removing the substrate to manufacture an ultra-small double LED device having a back-to-back structure.

Specifically, according to a preferred embodiment of the present invention, step 3) is

3-1) forming a support film on the second electrode layer;

3-2) forming an insulating film on the outer peripheral surface including the first active layer and the second active layer;

3-3) coating a hydrophobic film on the insulating film;

3-4) removing the substrate;

3-5) forming a first electrode layer under the first conductive semiconductor layer; and

3-6) removing the support film may include manufacturing a plurality of back-to-back ultra-small double LED devices.

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 the substrate 10 so that when the substrate 10 is removed through the laser lift-off (LLO) method, a plurality of back-to-back structure ultra-small double LED elements are not dispersed, and is attached to prevent cracks in the LED elements. As such, the material of the support film may be a polymer epoxy or a bonding metal, and the thickness may be 0.3 to 70 μm, but is not limited thereto.

8 shows an insulating film 80 formed on a portion of an outer peripheral surface including the first active layer and the second active layer for the ultra-small double LED devices having a back-to-back structure on which the supporting film of the present invention is formed. Through this, it is possible to achieve the effect of improving the lifespan and efficiency by minimizing defects on the surface of the ultra-small double LED device of the back-to-back structure. The insulating film serves to prevent an electrical short circuit occurring in the back-to-back micro-double LED device when the active layers included in the back-to-back structure are in contact with the mounting electrode. In addition, the insulating film protects the outer surface including the active layer of the ultra-small double LED device of the back-to-back structure, thereby preventing surface defects of the active layer, thereby preventing a decrease in luminous efficiency.

The insulating film includes not only the first active layer 12 and the second active layer 241 , but also the first conductive semiconductor layer 11 , the second conductive semiconductor layer 13 , the third conductive semiconductor layer 242 , and the fourth conductive layer. It may also be formed on the outer peripheral surface of the semiconductor layer 240, 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 ultra-small double LED devices of the back-to-back structure is a method of applying or immersing an insulating material on the outer circumferential surfaces of the ultra-small double LED devices of the back-to-back structure to which the support film 70 and the substrate 10 are attached. can be used, but is not limited thereto. The material that can be used as the insulating film is preferably SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ , hafnium oxide (HfO ₂ ), yttrium oxide (Y ₂ O ₃ ) and TiO ₂ Any selected from the group consisting of It may include one or more, but may be transparent, but is not limited thereto. In the case of a transparent insulating film, it is possible to minimize a decrease in luminous efficiency that may occur by coating the insulating film while serving as the above insulating film. Preferably. As a representative example, Al ₂ O ₃ film can be formed through ALD (atomic layer deposition) method, and TMA (trimethyl aluminum) and H ₂ O source are supplied in pulse form to form a thin film using chemical adsorption and desorption. can be formed

9 is a cross-sectional view showing the step of coating the insulating film 80 formed on the outer peripheral surface of the ultra-small double LED device of the present invention with a hydrophobic film 90 of the back-to-back structure. The hydrophobic film 90 has hydrophobic properties on the surface of the ultra-small double LED device having a back-to-back structure to prevent aggregation between the devices. It is a method that can eliminate a number of defects in the pixel patterning process of the ultra-small double LED device and can be formed on the insulating film 80 . In this case, the usable hydrophobic film may be used without limitation as long as it is formed on the insulating film to prevent aggregation between the ultra-small double LED elements having a back-to-back structure, and preferably octadecyltrichlorosilane (OTS). ), self-assembled monolayers (SAMs) such as fluoroalkyltrichlorosilane and perfluoroalkyltriethoxysilane, and fluoropolymers such as Teflon and Cytop ( fluoropolymer) may be used alone or in combination, but is not limited thereto.

10 is a cross-sectional view illustrating a step of removing the substrate 10 formed under the first conductive semiconductor layer 11 of the ultra-small double LED device having a back-to-back structure of the present invention. A method of removing the substrate 10 may use a commonly used method, preferably a chemical lift-off (CLO) or a laser lift-off (LLO) method, but is not limited thereto.

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 typically used for LED devices, and preferably Cr, Ti, Al, Au, Ni, ITO, and a material obtained by mixing alone or a mixture of oxides or alloys thereof. may be used, but is not limited thereto. In addition, the thickness of the electrode may be 0.02 ~ 1 ㎛, but is not limited thereto.

FIG. 12 illustrates manufacturing of the ultra-small double LED devices 121 and 122 having an independent back-to-back structure by removing the support film 70 .

13 is a perspective view illustrating a back-to-back ultra-small double LED device of the present invention, a first active layer 12 formed on the first conductive semiconductor layer 11 , and a second conductive semiconductor layer 13 formed on the first active layer 12 . ), and a third conductive semiconductor layer 242 formed on the second conductive semiconductor layer 13, a second active layer 241 formed on the third conductive semiconductor layer 242, and the second active layer 241 It includes a fourth conductive semiconductor layer 240 formed thereon, a first electrode 110 is formed under the first conductive semiconductor layer 11 , and a second electrode 110 is formed above the fourth conductive semiconductor layer 240 . Two electrodes 20 may be formed. Of course, as described above, a separate buffer layer, an active layer, a phosphor layer and/or a semiconductor layer may be further included. Meanwhile, the insulating film 80 and/or the hydrophobic film 90 includes a first active layer 12 formed on the first conductive semiconductor layer 11 and a second conductive semiconductor layer 13 formed on the first active layer 12 . and a third conductive semiconductor layer 242 formed on the second conductive semiconductor layer 13, a second active layer 241 formed on the third conductive semiconductor layer 242, and an upper portion of the second active layer 241 The fourth conductive semiconductor layer 240 may be formed to include and surround the outer peripheral surface of a part or all of the fourth conductive semiconductor layer 240 .

In addition, the first electrode 10 and/or the second electrode 20 may be formed to include and surround a part or all of the outer peripheral surface.

The shape of the ultra-small double LED device of the back-to-back structure of the present invention may be formed without limitation, such as a cylindrical shape, a rectangular parallelepiped shape, etc., but may preferably be a cylindrical shape, and in the case of a cylindrical shape, the diameter (circle diameter) may be 50 ~ 3000 nm, The height (length from the first electrode to the second electrode) may be 1.5 to 30 μm, but is not limited thereto.

In addition, as ink, paste or solution containing the ultra-small double LED devices of the present invention, the back-to-back structure of the ultra-small double LED elements of the present invention can be directly transferred to a subpixel of a display substrate or transferred in the form of ink or paste. there is.

The fabrication and structure of the ultra-small double LED device with the back-to-back structure of the present invention is very different from the case of the existing ultra-small single-type LED device. have characteristics.

1) Existing ultra-small single-type LEDs may have intrinsic electric dipoles due to their inherent asymmetry in their structure, but the back-to-back ultra-small double LED device of the present invention has an internally symmetrical structure (LED1 and LED2). The dipole is 0. Therefore, as will be described later, the principles of arranging them between the mounting electrodes are completely different from the existing ones. That is, the conventional ultra-small single-type LED device is based on electrophoresis, whereas the back-to-back ultra-small double LED device of the present invention operates based on dielectrophoresis. In addition, these driving electrodes, which will be described later, are different from each other, that is, in the case of the existing ultra-small single type LED device, light emission of the device is possible only with the first mounting electrode and the second mounting electrode, whereas the ultra-small size of the back-to-back structure of the present invention In the case of a double LED device, a third electrode is essential in addition to the first and second mounting electrodes.

As a next step, according to a preferred embodiment of the present invention for transferring the ultra-small double LED elements of the present invention in the form of ink, paste or solution to a substrate such as a display, as shown in FIG. 14, the present invention The electrode assembly of the ultra-small double LED having a back-to-back structure according to , has an electrode line including a first mounting electrode 610 and a second mounting electrode 630 spaced apart from each other, and one end is in contact with the first mounting electrode, and the other end is It is implemented by including a plurality of back-to-back ultra-small double LED elements 121 and 122 having an improved axial ordering in contact with the second mounting electrode.

In addition, a third electrode 150 is further included between the first mounting electrode and the second mounting electrode, and the central portion of the plurality of back-to-back ultra-small double LED devices, that is, the second conductive semiconductor layer and the third A portion of the conductive semiconductor layer may be in contact with the third electrode. That is, in the case of the ultra-small double LED electrode assembly having a back-to-back structure manufactured according to an embodiment of the present invention, a DC voltage is applied as a driving power source between the first and third electrodes and between the second and third electrodes. When this is done, the intensity of light emission of the ultra-small double LED device having a back-to-back structure can be significantly increased.

14 , as an example, in an ultra-small double LED electrode assembly having a back-to-back structure, the first mounting electrode 610 , the second mounting electrode 630 , and the third electrode 150 are positioned on the same plane, and the back-to-back structure of the LED electrode assembly is By connecting the ultra-small double LED devices 121 and 122 to the electrodes, light extraction efficiency of the back-to-back ultra-small double LED device can be improved.

On the other hand, in the electrode assembly of the ultra-small double LED of the back-to-back structure as shown in FIG. 14 , the size of the back-to-back structure of the ultra-small double LED device, including the width of the electrode and the distance between the electrodes, is all micro or nano scale, so a person or a machine is separated into individual pieces. It is impossible to manufacture by mounting each of the ultra-small double LED devices with a back-to-back structure.

Accordingly, the early inventors brought a solution containing an ultra-small single-type LED device into contact with a micro-electrode line, and then applied the assembly power to align and arrange the ultra-small single LED device on two different mounting electrodes. A single type LED electrode assembly was fabricated.

However, the ultra-small single type LED electrode assembly as shown in FIG. 15A has a problem in that the actual light-emitting device is significantly reduced when a DC voltage instead of an AC voltage is used as a driving power source. Specifically, for the same ultra-small single type LED electrode assembly, the light emission degree of the ultra-small single type LED electrode assembly that is driven according to a DC voltage and emits light by changing the driving power source and the ultra small single type LED electrode assembly that emits light by being driven according to an AC voltage is compared, When a DC voltage is used as a driving power source, the luminance of light emission is significantly reduced.

The problem of the decrease in luminance in such a DC driving power supply is because there is no polarity orientation between different conductive semiconductors (Ex. p-type semiconductor, n-type semiconductor) of the ultra-small single LED element in the electrode assembly and the different mounting electrodes in contact with each other ( biaxial axial ordering, not polar ordering). Specifically, as can be seen in FIG. 15A , the same type of semiconductor is in contact with the first mounting electrode 510 as the first ultra-small single LED device 123 among ten ultra-small single-type LED devices mounted on the ultra-small single type LED electrode assembly. The number of elements is five, and in the other five ultra-small single-type LED elements 124 , different types of semiconductor elements are in contact with the first mounting electrode 510 . Therefore, when a unidirectional DC driving power is applied to the ultra-small single-type LED electrode assembly as shown in FIG. 15A, only five ultra-small single LED devices emit light, and the remaining five ultra-small single LED devices do not emit light, which is directly related to a decrease in luminance. do.

After all, when aligning the ultra-small single type LED device by the conventional manufacturing method, both ends of the ultra-small single type LED device could be in contact with two different electrodes with an axial ordering (not polar ordering), respectively, but the manufactured Looking at the miniature single type LED electrode assembly, a specific end, for example, a p-type semiconductor, does not contact only the first mounting electrode, but a part of the miniature single type LED devices is an n-type semiconductor in contact with the first mounting electrode. was in contact with the first mounting electrode, that is, the ultra-small single-type LED devices were aligned with orientation, but this is axial ordering, not polar ordering. In addition, since the probability of non-polar orientation is 50% as to which semiconductor layer is in contact with a specific mounting electrode more, based on this, it is slightly different every time an ultra-small single type LED electrode assembly is manufactured, so in some cases, a DC voltage is accidentally driven Although an ultra-small single type LED electrode assembly capable of emitting light as a power source can be manufactured, such an electrode assembly cannot always be manufactured.

Accordingly, a group of inventors put a solution containing a micro-single LED device into a micro-electrode line, and then applied an asymmetric assembly power to make a specific semiconductor layer in the micro-single LED device contact a specific mounting electrode (see Fig. 15b). . Specifically, it was confirmed that the first conductive semiconductor layer or the second conductive semiconductor layer can be aligned with the first mounting electrode or the second mounting electrode, and accordingly, the characteristic capable of being driven through a DC driving power is developed.

However, in the case of aligning the miniature single type LED device by the conventional manufacturing method, both ends of the ultra miniature single type LED device could be in contact with two different electrodes, respectively. One of the first ultra-small single-type LED devices 123 has a specific end, for example, the first conductive semiconductor layer does not contact only the first mounting electrode, but some of the ultra-small single LED devices 124 have a second conductive semiconductor layer. 1 It was in contact with the mounting electrode. That is, the ultra-small single-type LED devices have been aligned with polarity orientation, but their polarity orientation is still at a low level.

Accordingly, the inventors of the present invention have discovered the following alignment conditions. That is, in order to solve the problem of the polarity alignment of the conventional ultra-small single LED device described above, a solution containing a back-to-back structure ultra-small double LED device of the present invention is prepared and in contact with the substrate on which the mounting electrode is formed, and a symmetrical assembly voltage is applied. Accordingly, when the back-to-back ultra-small double LED device is aligned, the semiconductor layers at both ends of the back-to-back ultra-small double LED device may contact the mounting electrodes. For example, the first conductive semiconductor layer and the fourth conductive semiconductor layers of the back-to-back structure of the ultra-small double LED device are in contact with the first and second mounting electrodes, so that the back-to-back structure of the ultra-small double LED device has improved non-polar arrangement can be sorted with In addition, the third electrode previously formed between the first mounting electrode and the second mounting electrode has a back-to-back structure at the center of the ultra-small double LED device, that is, a portion of the second conductive semiconductor layer and the third conductive semiconductor layer is in contact with the third electrode. can be Accordingly, when DC driving power is applied between the first mounting electrode and the third electrode and between the second mounting electrode and the third electrode, direct current driving is possible, so that the light emission intensity of the ultra-small double LED device having a back-to-back structure is significantly increased. We have come to the present invention, which makes it possible.

Hereinafter, a method for manufacturing an ultra-small double LED electrode assembly having a back-to-back structure according to the present invention that enables driving by the DC voltage as described above will be described.

The ultra-small double LED electrode assembly having a back-to-back structure with improved non-polar arrangement according to the present invention includes (1) a first mounting electrode and a plurality of second mounting electrodes formed to be spaced apart from the first mounting electrode on an upper portion of an electrode line. Contacting a solution containing a back-to-back ultra-small dual LED device; (2) By applying power having an assembly voltage of 1.0 V or higher to the plurality of back-to-back micro-dual LED devices through the electrode line, changes in electrical force and torque force are generated in the plurality of back-to-back structured ultra-small double LED devices to move and rotate the plurality of back-to-back structured ultra-small double LED devices to a non-polar arrangement in one direction, so that the ends of the plurality of back-to-back structured ultra-small double LED devices are arranged in a non-polar manner to the first and second mounting electrodes It can be prepared including;

Here, the step of contacting the ends of the plurality of back-to-back ultra-small double LED devices with the first mounting electrode and the second mounting electrode with a non-polar arrangement includes the first conductivity of the plurality of back-to-back structured ultra-small double LED devices. It means a step in which the semiconductor layer and the fourth conductive semiconductor layer are in contact with the first mounting electrode and the second mounting electrode to have a non-polar arrangement.

In addition, if necessary, the central portion of the ultra-small double LED device having a back-to-back structure disposed in a non-polar arrangement on the third electrode formed to be spaced apart between the first and second mounting electrodes, that is, the second conductive semiconductor layer and the second electrode. 3 means a step in which the conductive semiconductor layer is in contact.

By such an operation, it can be expected that the non-polar arrangement of a plurality of back-to-back ultra-small double LED devices is increased, and accordingly, it is possible to apply a symmetrical assembly voltage and shorten the process time.

The step of contacting the solution including a plurality of back-to-back ultra-small double LED elements on the upper portion of the electrode line of the present invention means contacting the solution on the upper portion of the electrode line, and the solution is dropped onto the electrode line. method, immersion in a solution, etc. can be used.

First, in step (1), a plurality of back-to-back ultra-small double LED devices in an electrode line including the micro-miniature first mounting electrode and a second mounting electrode formed to be spaced apart from the first mounting electrode, and a solution that can contain them Steps to contact

Specifically, FIG. 16 is a schematic diagram of a manufacturing process of an ultra-small double LED electrode assembly having a back-to-back structure according to a preferred embodiment of the present invention, and FIG. 16A is a first mounting electrode 610 formed on the base substrate 100, the first A solution containing a second mounting electrode 630 spaced apart from the mounting electrode on the same plane and a plurality of back-to-back ultra-small double LED devices (back-to-back structure ultra-small double LED device 121, solvent 140) is shown. . Although not shown in FIG. 16B, after the solution containing the ultra-small double LED device of the back-to-back structure is contacted on the mountable area of the electrode line into which the solution containing the ultra-small double LED device of the back-to-back structure is put, the ultra-small double LED of the back-to-back structure An insulating barrier rib or an insulating film may be further provided so that the devices are gathered within the electrode line region to be mounted.

In addition, although not shown in FIG. 16 , a third electrode spaced apart from the first mounting electrode and the second mounting electrode may be further provided, if necessary.

In addition, an external magnetic field may be further provided to gather within the electrode line region.

Description of the specific manufacturing method of the base substrate, the electrode line including the first mounting electrode and the second mounting electrode, the insulating barrier rib that may be formed on the electrode line, the external magnetic field, etc. is provided in Korean Patent Registration No. 10-1429095 , Republic of Korea Patent Publication No. 10-2019-0113695 may be inserted as a reference, so the present invention will omit a detailed description thereof.

Next, in step (2) according to the present invention, in order to contact the ends of the micro LED device to the first mounting electrode and the second mounting electrode to the ultra-small double LED device of the back-to-back structure, the voltage on the electrode line is 1.0 An assembly power greater than V can be applied.

The applied assembly voltage is a symmetric voltage, and the frequency of the symmetric voltage is adjusted to perform a step of mounting a plurality of back-to-back micro-dual LED devices ( FIG. 16C ).

In the step (2), the electric field formed between the mounting electrodes by the application of a symmetrical voltage and the electric field-induced dipole of the back-to-back structure of the ultra-small double LED device interact (electric force and torque force generation) through interaction (electric force and torque force generation), eventually the device may move and rotate by itself to align and mount with a non-polar arrangement between the first and second mounting electrodes. That is, it is possible to apply a symmetric assembly voltage to the ultra-small double LED device having a back-to-back structure.

However, in order to improve the non-polar orientation of the ultra-small double LED devices of the back-to-back structure, which are mounted so that the device not only moves and aligns with the electrode, but also contacts the first mounting electrode of the first conductive semiconductor layer or the fourth conductive semiconductor layer in the device, For symmetric assembly voltage, a voltage with a voltage strength of 1.0 V or more must be applied.

A conventional ultra-small single-type LED electrode assembly by some inventors used a symmetrical assembly voltage in step (2) (Korean Patent Laid-Open Publication No. 10-2019-0113695). Then, what happens when this symmetric assembly voltage is applied to the ultra-small single type LED is shown in FIG. 17A. There are many electrons in the semiconductor constituting the micro LED, and when a voltage or an electric field is applied to these electrons from the outside, the micro LED tends to rotate in the direction of the electric field. This is because electrons in the ultra-small LED move by an external voltage or electric field, resulting in electrical polarization. The degree to which such polarization is likely to occur is called the dielectric constant, and since the ultra-small LED is not spherical in structure, the dielectric constant varies depending on the direction of the device, and this characteristic is called dielectric anisotropy (Δε). So, when a voltage (electric field) is applied to the micro LED solution, induced polarization occurs in the micro LED in the long axis direction, and the polarization direction is stable only when the direction of the polarization is parallel to the direction of the external electric field ( E ) (potential energy U _induced = - (1/2)ΔεE ² ), the ultra-small LED tries to change its direction to that of an external voltage. This is very similar to the principle that when a metal needle is placed between the N and S poles of a magnet, the needle rotates toward the direction between the two poles. (In addition, the rotation of non-polar arrangement due to dielectric anisotropy similarly occurs in liquid crystal molecules.) However, as shown in the last figure, even if the device is arranged with the orientation reversed, the induced polarization follows the direction of the electric field, so it is still in a stable state. Therefore, the probability that the device is polarized in one direction is 50%, therefore, it is insufficient to maximize the polarity orientation of the ultra-small single-type LED device to a specific mounting electrode, and the ultra-small single-type LED device has an appropriate level of polarity orientation. It is difficult to mount (see Fig. 17A).

On the other hand, by some inventors, a unidirectional polar arrangement of an ultra-small LED device by applying an asymmetric assembly voltage having an asymmetric waveform in a micro-electrode line and having an upper peak voltage different from that of a lower peak voltage A manufacturing method for implementing an assembly with increased polar ordering and an ultra-small LED electrode assembly were implemented. (Republic of Korea Patent Publication No. 10-1730927) This is due to the inherent asymmetry of the ultra-small single-type LED. In the ultra-small LED, intrinsic dipole, dipole p = charge (q) * distance ( d ) ) can have When an external asymmetric assembly voltage is applied to the micro LED solution, along with electrophoresis, the intrinsic electric dipole is stable only when aligned in the opposite direction to the direction of the external electric field (potential energy U _dipole = - p E ). Trying to change your direction. This is very similar to the principle that when a small magnet (eg a compass) is placed between the N and S poles of a large magnet, the small magnet rotates toward one pole of the large magnet. However, since the application of a high electric field is required along with the interaction between the miniature LEDs, this was also insufficient to realize high polarity alignment (see FIG. 17b ).

In contrast, in order to examine a case in which an assembly voltage is applied to the ultra-small double LED device having a back-to-back structure of the present invention, FIGS. 17C and 17D will be described with reference to FIG. Existing ultra-small single-type LEDs may have intrinsic electric dipoles due to their inherent asymmetry ( p ≠ 0), but the back-to-back ultra-small double LED device of the present invention has an internally symmetric structure (LED1 and LED2). Therefore, the intrinsic electric dipole is zero ( p = 0). Therefore, when the symmetric assembly voltage of the present invention is applied, polarization is induced in the long-axis direction by the dielectric anisotropy of the device described above in the ultra-small double LED device having a back-to-back structure, thereby generating an electrically-induced dipole, and this electric-induction The device moves by itself under the influence of the interaction (electric force) and dielectrophoresis of the symmetric electric field formed between the dipole and the mounting electrode, and the device rotates through the generation of torque force of the device described above, improving non-polar arrangement between the electrodes It can be mounted by sorting with . When looking at this extension, a plurality of back-to-back ultra-small double LED devices with a non-polar orientation applied to the mounting electrode can more easily contact the first mounting electrode or the second mounting electrode (see FIGS. 17c and d).

At this time, the assembly power applied to the mounting electrode is possible at 1.0 V or more, and 25 V or more may be used.

If the assembling voltage is less than 1.0 V, the orientation that causes the specific semiconductor layer of the miniature LED device to come into contact with the specific mounting electrode is reduced, so that the luminance is remarkably improved when driving power is applied to the manufactured back-to-back structured subminiature double LED electrode assembly. There is a problem with degradation.

On the other hand, when the assembling voltage exceeds 500 V, there is no problem with the orientation in a specific direction of the ultra-small double LED device of the back-to-back structure, but there is a risk that various substrates including the mounting electrode may be damaged. It is preferable to have a non-polar arrangement.

In addition, according to an embodiment of the present invention, the frequency of the assembled power supply may be 0.1 Hz ~ 1 GHz, and more preferably, the frequency may be a power supply of 10 kHz ~ 100 MHz. In addition, the power source may be a symmetric AC power source having the form of a sine wave, a square wave, or a triangular wave.

As a next step after performing step (2), heat treatment of the electrode line and the ultra-small double LED device having a back-to-back structure aligned on the electrode line at 300 to 1000° C. for 0.5 to 10 minutes may be further performed. In this case, the heat treatment temperature may be more preferably performed at 600° C. or higher. The heat treatment process is a process for removing the solvent injected to facilitate movement and alignment of the back-to-back structure of the ultra-small double LED device after contacting the back-to-back structure of the ultra-small double LED device with different mounting electrodes, respectively. When driving power is applied between the mounting electrodes and the third electrode in a state in which the solvent is not completely removed, the back-to-back structure of the ultra-small double LED electrode assembly may not exhibit desired levels of luminance and efficiency.

If the heat treatment is performed at less than 300 ° C. and / or less than 0.5 minutes, there may be a problem that impurities are not completely removed and a problem that the contact reaction between the back-to-back structure ultra-small double LED device and the electrode may not completely occur, If it exceeds 1000℃ and/or exceeds 10 minutes, the base substrate and/or electrode may be deformed or broken, and the voltage may not be properly applied to the back-to-back structure ultra-small double LED device due to the increase in resistance. can occur

On the other hand, in the method for manufacturing an ultra-small double LED electrode assembly having a back-to-back structure according to a preferred embodiment of the present invention, the step of forming an insulating film on the first mounting electrode and the second mounting electrode is further performed before step (1). can

The insulating film may be used without limitation as long as it is a conventional method known in the art, so the present invention is not limited to a specific method thereof, and a description thereof will be omitted. Also, a known material may be used for the material of the insulating layer. The insulating layer is made of an inorganic material such as SiO ₂ , SiN _x , SiON, Al ₂ O ₃ , TiO ₂ , HfO ₂ . Alternatively, the insulating film may be composed of a single layer or a multi-layer as an organic insulator. The insulating layer may have a thickness of several tens of nm to several μm.

On the other hand, the method for manufacturing an ultra-small double LED electrode assembly having a back-to-back structure according to a preferred embodiment of the present invention is a back-to-back ultra-small double LED with the first mounting electrode, the second mounting electrode, and the third electrode after step (3). The step of forming a metal ohmic layer on the contact portion of the device may be further performed.

The forming step of the metal ohmic layer is preferably performed after step (3) described above.

The reason for forming the metal ohmic layer on the contact portion is to further increase luminous efficiency by reducing contact resistance that may occur between the electrode and the back-to-back ultra-small double LED device when driving power is applied. The metal ohmic layer may be used without limitation as long as it is a conventional method known in the art, such as electroless plating, so that the present invention is not limited to a specific method thereof, and a description thereof is also omitted. Also, a known material may be used for the material of the metal ohmic layer.

On the other hand, in the method for manufacturing a back-to-back structure of an ultra-small double LED electrode assembly according to a preferred embodiment of the present invention, a transfer step may be performed as a next step after performing the above-described step (2). In order to utilize the ultra-small dual LED elements of the back-to-back structure in a display device, if necessary, they may be assembled or transferred to a separate final substrate. The final substrate is a substrate on which a wiring electrode for applying a voltage to the back-to-back structure of the ultra-small double LED device is formed so that the back-to-back structure of the ultra-small double LED device can emit light. Therefore, the ultra-small double LED devices having a back-to-back structure that emit light in each color can be transferred back to the final substrate after moving and assembly to a transfer substrate or an assembly substrate. In some cases, when a wiring process is directly performed on the transfer substrate or the assembly substrate, the transfer substrate or the assembly substrate serves as a final substrate.

When a plurality of back-to-back ultra-small double LED devices constituting individual unit pixels are disposed on the final substrate, a wiring process for electrically connecting the back-to-back ultra-small double LED devices may be performed. The wiring electrode formed through the wiring process electrically connects the ultra-small double LED elements of the back-to-back structure assembled or transferred to the substrate with the substrate. Also, a transistor for driving an active matrix may be previously formed under the substrate. Accordingly, the wiring electrode may be electrically connected to the transistor.

The ultra-small double LED electrode assembly of the back-to-back structure implemented through the manufacturing method according to the embodiment of the present invention described above is a first mounting electrode 610 and a second mounting electrode 630 that are spaced apart from each other as shown in FIG. 14 . and an electrode line including a third electrode 150 and a plurality of back-to-back structures in which one end is in contact with the first mounting electrode, the other end is in contact with the second mounting electrode, and a central portion is in contact with the third electrode. Includes ultra-small double LED elements (121, 122).

In addition, the ultra-small double LED device of the back-to-back structure mounted on the ultra-small double LED electrode assembly of the back-to-back structure according to the present invention emits light of about 80% or more of the ultra-small double LED device of the back-to-back structure of the total number of the mounted back-to-back structure of the ultra-small double LED device In this way, sufficient luminance characteristics can be expressed, and as DC is used as a driving power source, the circuit configuration is more simplified, which can be advantageous in terms of production efficiency and production cost. If less than 80% of the back-to-back ultra-small double LED devices of the entire mounted back-to-back structure exhibit non-polar orientation, the displayed luminance may be significantly reduced.

In addition, in the back-to-back ultra-small double LED electrode assembly according to an embodiment of the present invention, the number of back-to-back ultra-small double LED elements mounted per unit light emitting pixel may be one or more. On the other hand, the average mounting number of the ultra-small double LED device of the back-to-back structure per unit area does not mean the total area including the electrode area in which the ultra-small double LED device of the back-to-back structure cannot be substantially mounted, and the ultra-small double LED device of the back-to-back structure is substantially It refers to the number of units converted to the number of ultra-small double LED elements of the back-to-back structure mounted on the basis of the area of the electrode line that can be mounted as a .

On the other hand, the ultra-small double LED device of the back-to-back structure provided in the ultra-small double LED electrode assembly of the back-to-back structure can be used without limitation, if the structure of the LED device widely used in general light sources, displays, etc. is included, preferably the back-to-back structure The length of the ultra-small double LED device of the structure may be 100 nm to 30 μm, and more preferably 500 nm to 15 μm. If the length of the ultra-small double LED device having a back-to-back structure is less than 100 nm, it is difficult to manufacture a high-efficiency LED device, and if it exceeds 30 μm, the luminous efficiency of the LED device may be reduced.

The ultra-small double LED device of the back-to-back structure has a length of the ultra-small LED device, that is, a first conductive semiconductor layer, a first active layer, a second conductive semiconductor layer, a third conductive semiconductor layer, a second active layer, and a fourth conductive semiconductor. It means the ratio (L/r) of the length or diameter (r) in the width direction of both cross-sections of the element to the total length (L) in the thickness direction of the LED element including the layer or the like. For example, if the back-to-back ultra-small double LED device has a cylindrical shape, when the cross-section of the device, that is, the diameter (r) of the circle is 10 μm, the aspect ratio of less than 1.2 is the range of the length (L) of the device is less than 12 μm. it means.

In addition, even when a square semiconductor light emitting device having a side length of 10 μm is used as a unit pixel, sufficient brightness to form a display device appears. Accordingly, if the size of the unit pixel is a rectangular pixel having one side of 600 μm and the other side of 300 μm, for example, the distance between the semiconductor light emitting devices is relatively large.

The shape of the ultra-small double LED device of the back-to-back structure of the present invention may be various shapes such as a cuboid, a cube, an ellipsoid, a cylinder, and a disk type, and may preferably be a cylindrical shape, but is not limited to the above description.

The ultra-small double LED device having the back-to-back structure may be both a horizontal semiconductor light emitting device and a vertical semiconductor light emitting device. However, in the case of a vertical semiconductor light emitting device, since the first conductive electrode and the second conductive electrode have a structure that faces each other, the semiconductor light emitting device is separated from the growth substrate and a conductive electrode in one direction is formed in a subsequent process add the process In addition, for the polarity arrangement assembly process, the LED device may include a magnetic layer.

More specifically, the ultra-small double LED device of the back-to-back structure may have a vertical structure. As another example, the miniature LED device may be a flip chip type light emitting device. In addition, the aspect ratio of the ultra-small LED device may be 1.0 or more and 200 or less, more preferably 1.2 to 100, even more preferably 1.5 to 50, particularly preferably 1.5 to 30 in the case of the rod-shaped type. In addition, in the case of a disk type, the aspect ratio of the ultra-small LED device of the present invention may be in a range of less than 1.2, preferably less than 0.1, and more preferably less than 0.01.

On the other hand, the present invention includes a light source including the ultra-small double LED electrode assembly of the back-to-back structure according to the present invention described above. The light source may further include a support for accommodating or supporting the ultra-small double LED electrode assembly having a back-to-back structure, but is not limited thereto. I never do that.

In addition, the light source may further include a phosphor that is provided inside the support and is excited by light emitted from the ultra-small double LED device having a back-to-back structure. For example, when the back-to-back structure of the ultra-small double LED device is a UV ultra-small LED device, the phosphor that can be excited by UV may be any one of blue, yellow, green, amber and red phosphor, in this case, It may be a monochromatic LED light source emitting light of any one selected color. In addition, preferably, the phosphor excited by UV may be any one or more of blue, yellow, green, amber and red, and more preferably blue/yellow, blue/green/red and blue/green/amber/red. Any one type of mixed phosphor may be used, and in this case, white light may be irradiated by the phosphor.

As the specific phosphor can be selected and used in consideration of the emission color emitted by the selected back-to-back structure of the ultra-small double LED device, the detailed description thereof will be omitted in the present invention.

In addition, the present invention may be a lighting, a backlight unit, a light source for medical and bio use, a light source for a private vehicle, a light source for communication, a light source for a wearable device, and a display including the ultra-small double LED electrode assembly having a back-to-back structure according to the present invention.

Specifically, the LED display supports and accommodates a light emitting unit using the back-to-back structure of the ultra-small double LED electrode assembly as a sub-pixel, a light conversion layer including a quantum dot positioned thereon, and the light emitting unit and the light conversion layer. It may include a support member. In this case, an optical sheet disposed on the support member to suppress reflection of light incident from the outside may be further provided, and a heat dissipation member may be further provided under the light emitting unit unit. The ultra-small double LED electrode assembly having a back-to-back structure according to an embodiment of the present invention may be provided in the light emitting unit as a light source.

The display may be a flexible display. The flexible display includes a display that can be bent, bent, twisted, folded, or rolled by an external force. For example, the flexible display may be a display manufactured on a thin and flexible substrate that can be bent, bent, folded, or rolled like paper while maintaining the display characteristics of a conventional flat panel display.

In addition, the display device includes a passive matrix (PM) type display device as well as an active matrix (AM) type display device as the display device.

Since each configuration of the display may employ a configuration known in the field of display, a detailed description thereof will be omitted in the present invention.

In the above, the present invention has been mainly described with respect to the embodiment, but this is only an example and does not limit the embodiment of the present invention. It can be seen that various modifications and applications not exemplified above are possible without departing from the scope.

For example, each component specifically shown in the embodiment of the present invention can be implemented by modification. And differences related to such modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

The ultra-small LED device of the present invention can be widely used in the display industry.

10: substrate 11: first conductive semiconductor layer
12: first active layer 13: second conductive semiconductor layer
242: a third conductivity type semiconductor layer;
241: a second active layer;
240: fourth conductive semiconductor layer
20: second electrode layer 21: insulating layer
22: metal mask layer

Claims (20)

1) on the board
A first LED layer is sequentially formed, including a first conductive semiconductor layer, a first active layer, and a second conductive semiconductor layer,
A third conductive semiconductor layer, a second active layer, and a fourth conductive semiconductor layer are sequentially formed on the second LED layer in reverse order,
sequentially forming a double LED device layer having a back-to-back structure;
2) The diameter of the double LED device of the back-to-back structure including the first conductive semiconductor layer, the first active layer, the second conductive semiconductor layer, the third conductive semiconductor layer, the second active layer, and the fourth conductive semiconductor layer is nano or etching to have a micro size; and
3) removing the substrate;
A method of manufacturing a back-to-back ultra-small double LED device comprising a. According to claim 1,
The first conductive semiconductor layer and the fourth conductive semiconductor layer include at least one n-type semiconductor layer, and the second conductive semiconductor layer and the third conductive semiconductor layer include at least one p-type semiconductor layer. A method of manufacturing an ultra-small double LED device having a back-to-back structure. According to claim 1,
The first conductive semiconductor layer and the fourth conductive semiconductor layer include at least one p-type semiconductor layer, and the second conductive semiconductor layer and the third conductive semiconductor layer include at least one n-type semiconductor layer. A method of manufacturing an ultra-small double LED device having a back-to-back structure. The method of claim 1, wherein step 2) comprises;
2-1) forming a second electrode layer, an insulating layer, and a metal mask layer on the fourth 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) The first conductive semiconductor layer, the first active layer, the second conductive semiconductor layer, the third conductive semiconductor layer, the second active layer, and the fourth conductive semiconductor layer, including the dry or wet etching; and
2-4) A method of manufacturing a back-to-back ultra-small double LED device comprising the step of removing the insulating layer, the metal mask layer, and the polymer layer. The method of claim 1, wherein step 2) comprises;
2-5) forming a second electrode layer, an insulating layer, and a metal mask layer on the fourth conductive semiconductor layer;
2-6) forming a nanosphere or microsphere monolayer on the metal mask layer and performing self-assembly;
2-7) Dry method at nano or micro intervals depending on the pattern, including the first conductive semiconductor layer, the first active layer, the second conductive semiconductor layer, the third conductive semiconductor layer, the second active layer, and the fourth conductive semiconductor layer or wet etching; and
2-8) A method of manufacturing a back-to-back ultra-small double LED device comprising the step of removing the insulating layer, the metal mask layer, and the single layer. 6. The method of claim 5,
The nanosphere or microsphere is a method of manufacturing a back-to-back structure ultra-small double LED device, characterized in that the polystyrene material. The method of claim 5, wherein step 3) is;
3-1) forming a support film on the second electrode layer;
3-2) forming an insulating film on the outer peripheral surface including the first active layer and the second active layer;
3-3) removing the substrate;
3-4) forming a first electrode layer under the first conductive semiconductor layer; and
3-5) A method of manufacturing a back-to-back ultra-small double LED device comprising the step of manufacturing a plurality of back-to-back ultra-small double LED devices by removing the support film. a first conductive semiconductor layer;
a first active layer formed on the first conductive semiconductor layer;
a second conductive semiconductor layer formed on the first active layer;
a third conductive semiconductor layer formed on the second conductive semiconductor layer;
a second active layer formed on the third conductive semiconductor layer; and
Containing; a fourth conductive semiconductor layer formed on the second active layer
An ultra-small double LED device having a back-to-back structure including a semiconductor light emitting device having a diameter of micro or nano size. 9. The method of claim 8,
The semiconductor light emitting device includes an insulating film coated on a part of the outer circumferential surface and
A back-to-back ultra-small double LED device including a hydrophobic film coated on the insulating film. 10. The method of claim 9,
a first electrode layer formed under the first conductive semiconductor layer; and
A back-to-back ultra-small double LED device comprising a second electrode layer formed on the fourth conductive semiconductor layer. 9. The method of claim 8,
The first conductive semiconductor layer and the fourth conductive semiconductor layer include at least one n-type semiconductor layer, and the second conductive semiconductor layer and the third conductive semiconductor layer include at least one p-type semiconductor layer. Ultra-small double LED device with back-to-back structure. 11. The method according to any one of claims 9 to 10,
The insulating film includes at least one selected from the group consisting of SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ and TiO ₂ ; The hydrophobic film is a back-to-back ultra-small double LED device comprising at least one component of SAMs and a fluoropolymer. (1) contacting a solution including a plurality of back-to-back ultra-small double LED devices on an electrode line including a first mounting electrode and a second mounting electrode formed to be spaced apart from the first mounting electrode;
(2) A symmetrical power source having an assembly voltage of 1.0 V or higher is applied through the first mounting electrode and the second mounting electrode line to generate electric and torque forces to the plurality of back-to-back ultra-small double LED devices. By moving and rotating the back-to-back structure of the ultra-small double LED device to a non-polar arrangement in one direction, the ends of the plurality of back-to-back structured ultra-small double LED devices are arranged in the first and second mounting electrodes with non-polarity, A method for manufacturing an ultra-small double LED electrode assembly having a back-to-back structure with improved non-polar arrangement, characterized in that contact. 14. The method of claim 13,
In the step (1), it characterized in that it further comprises a third electrode formed to be spaced apart between the first mounting electrode and the second mounting electrode,
In step (2), the plurality of back-to-back ultra-small double LED devices are arranged between the first mounting electrode and the second mounting electrode so that a second conductive semiconductor layer or a third conductive semiconductor layer at the center of the device is the third Contacting the electrode; back-to-back structure ultra-small double LED electrode assembly manufacturing method further comprising a. 15. The method of claim 13 or 14,
After performing step (2),
(3) heat-treating the plurality of back-to-back ultra-small double LED devices arranged on the electrode line at 300° C. to 1,000° C. for 0.5 to 10 minutes; A method for manufacturing an ultra-small double LED electrode assembly with a structure. 14. The method of claim 13,
In the step (1), a method for manufacturing an ultra-small double LED electrode assembly having a back-to-back structure with improved non-polar arrangement, characterized in that it further comprises an insulating layer on the first and second mounting electrodes. an electrode line including a first mounting electrode and a second mounting electrode spaced apart from each other; and
A non-polarity comprising a; one end contacting the first mounting electrode and the other end contacting the second mounting electrode, a back-to-back structure with improved non-polar arrangement by applying a symmetric assembly voltage Ultra-small double LED electrode assembly with back-to-back structure with improved arrangement. 18. The method of claim 17,
The ultra-small double LED electrode assembly of the back-to-back structure is
an electrode line further comprising a third electrode spaced apart from the first mounting electrode and the second mounting electrode; and
a miniature dual LED device having a back-to-back structure with improved nonpolar arrangement by applying a symmetric assembly voltage, in which one end contacts the first mounting electrode, the other end contacts the second mounting electrode, and the center contacts the third electrode; An ultra-small double LED electrode assembly of a back-to-back structure with improved non-polar arrangement comprising a. A light source including; the ultra-small double LED electrode assembly of the back-to-back structure according to claim 18. A display including; the ultra-small double LED electrode assembly of the back-to-back structure according to claim 18.

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