Patent Publication Number: US-2022238759-A1

Title: Display device using micro led

Description:
TECHNICAL FIELD 
     The present disclosure relates to a display device using a micro-LED (or micro LED), and more particularly, to a display device using a semiconductor light emitting device with a size of several pm to several tens of pm. 
     BACKGROUND ART 
     In recent years, display devices having excellent characteristics, such as a thin shape, flexibility, and the like, are being developed in a field of a display technology. Currently commercialized main displays are represented by liquid crystal displays (LCDs) and active matrix organic light emitting diodes (AMOLEDs). 
     Light emitting diodes (LEDs), which are well known light emitting devices for converting an electrical current to light, have been used as a light source for displaying an image in an electronic device including information communication devices since red LEDs using GaAsP compound semiconductors were made commercially available in  1962 , together with a GaP:N-based green LEDs. Accordingly, the semiconductor light emitting devices may be used to implement a display, thereby presenting a scheme for solving the problems. 
     When manufacturing a display device using semiconductor light emitting devices, a step of high temperature exposure may be included. In the related art display device using semiconductor light emitting devices, a conductive adhesive is mainly used. When the conductive adhesive is exposed to a high temperature, an adhesive force may be lost, causing the semiconductor light emitting devices to be separated from a substrate. This leads to a reduction in productivity of the display device. Thus, attempts have been made to manufacture a display device without using a conductive adhesive. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     The present disclosure describes semiconductor light emitting devices capable of maintaining light emitting ability even when a part of the semiconductor light emitting devices is damaged. 
     Solution to Problem 
     According to one aspect of the subject matter described in this application, a display device includes a substrate including a plurality of electrode lines, and a plurality of semiconductor light emitting devices disposed on the substrate and electrically connected to the electrode lines. Each of the plurality of semiconductor light emitting devices includes a first conductive semiconductor layer, a second conductive semiconductor layer formed on the first conductive semiconductor layer, and an active layer formed between the first and second conductive semiconductor layers. The second conductive semiconductor layer is provided in plurality on the first conductive semiconductor layer, such that a plurality of active layers spaced apart from each other are formed on each of the plurality of semiconductor light emitting devices. 
     In some implementations, each of the semiconductor light emitting devices may further include a first conductive electrode disposed on the first conductive semiconductor layer, and a plurality of second conductive electrodes disposed on the plurality of second conductive semiconductor layers, respectively. Each of the plurality of second conductive semiconductor layers may be electrically connected to one of the electrode lines. 
     In some implementations, the plurality of second conductive semiconductor layers may be connected in parallel to the same electrode line. 
     In some implementations, the plurality of second conductive semiconductor layers may be electrically connected to different electrode lines. 
     In some implementations, the plurality of second conductive semiconductor layers may be disposed at one surface of both surfaces of the first conductive semiconductor layer, and the first conductive electrode may be disposed on the one surface, of the both surfaces of the first conductive semiconductor layer, where the plurality of second conductive semiconductor layers are disposed. 
     In some implementations, the plurality of second conductive semiconductor layers may be disposed at one surface of both surfaces of the first conductive semiconductor layer, and the first conductive electrode may be disposed on a remaining one surface of the both surfaces of the first conductive semiconductor layer that is different from the one surface where the plurality of second conductive semiconductor layers are disposed. 
     According to another aspect, a semiconductor light emitting device includes a first conductive semiconductor layer, a second conductive semiconductor layer formed on the first conductive semiconductor layer, and an active layer formed between the first and second conductive semiconductor layers. The second conductive semiconductor layer is provided in plurality on the first conductive semiconductor layer, such that a plurality of active layers spaced apart from each other are formed on the semiconductor light emitting device. 
     Advantageous Effects of Invention 
     As a semiconductor light emitting device according to the present disclosure includes a plurality of light emitting regions, light emitting ability of the semiconductor light emitting device can be maintained even when one of the light emitting regions loses its light emitting ability. Accordingly, there is no need to dispose a plurality of semiconductor light emitting devices for each sub-pixel in preparation for semiconductor light emitting device damage. Thus, a high-resolution display with a very small distance between semiconductor light emitting devices can be achieved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a conceptual view illustrating a display device using a semiconductor light emitting device (diode) according to one implementation of the present disclosure. 
         FIG. 2  is a partially enlarged view illustrating a portion “A” of  FIG. 1 , and 
         FIGS. 3A and 3B  are cross-sectional views taken along the lines “B-B” and “C-C” of  FIG. 2 . 
         FIG. 4  is a conceptual view illustrating a flip chip type semiconductor light emitting device of  FIG. 3 . 
         FIGS. 5A to 5C  are conceptual views illustrating various forms of realizing a color in association with a flip chip type semiconductor light emitting device. 
         FIG. 6  is a cross-sectional view illustrating a method of manufacturing a display device using a semiconductor light emitting device according to the present disclosure. 
         FIG. 7  is a perspective view illustrating a display device using a semiconductor light emitting device according to another implementation of the present disclosure. 
         FIG. 8  is a cross-sectional view taken along the line “D-D” of  FIG. 7 . 
         FIG. 9  is a conceptual view illustrating a vertical type semiconductor light emitting device of  FIG. 8 . 
         FIG. 10  is a cross-sectional view illustrating a semiconductor light emitting device according to one implementation of the present disclosure. 
         FIGS. 11 and 12  are planar views illustrating a semiconductor light emitting device according to the present disclosure. 
         FIG. 13  is a conceptual view illustrating an example state in which semiconductor light emitting devices and wiring electrodes are connected to each other. 
         FIG. 14  is a conceptual view illustrating various modified examples of a semiconductor light emitting device according to the present disclosure. 
         FIG. 15  is a conceptual view illustrating a vertical type semiconductor light emitting device including a plurality of active layers. 
     
    
    
     MODE FOR THE INVENTION 
     Description will now be given in detail according to exemplary implementations disclosed herein, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components may be provided with the same or similar reference numbers, and description thereof will not be repeated. In general, a suffix such as “module” and “unit” may be used to refer to elements or components. Use of such a suffix herein is merely intended to facilitate description of the specification, and the suffix itself is not intended to give any special meaning or function. In describing the present disclosure, if a detailed explanation for a related known function or construction is considered to unnecessarily divert the main point of the present disclosure, such explanation has been omitted but would be understood by those skilled in the art. The accompanying drawings are used to help easily understand the technical idea of the present disclosure and it should be understood that the idea of the present disclosure is not limited by the accompanying drawings. 
     It will be understood that when an element such as a layer, area or substrate is referred to as being “on” another element, it can be directly on the element, or one or more intervening elements may also be present. 
     A display device disclosed herein may include a mobile phone, a smart phone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, a slate PC, a tablet PC, an ultrabook, a digital TV, a desktop computer, and the like. However, it will be readily apparent to those skilled in the art that the configuration according to the implementations described herein may also be applied to a new product type of display device that will be developed later. 
       FIG. 1  is a conceptual view illustrating a display device using a semiconductor light emitting device (diode) according to one implementation of the present disclosure. 
     As illustrated, information processed in a controller (or control unit) of a display device  100  may be displayed using a flexible display. 
     The flexible display may include a flexible, bendable, twistable, foldable, and rollable display. For example, the flexible display may be a display fabricated on a thin and flexible substrate that can be warped, bent, folded, or rolled like a paper sheet while maintaining the display characteristics of a flat display of the related art. 
     A display area of the flexible display becomes a plane in a state or configuration that the flexible display is not warped (e.g., a configuration having an infinite radius of curvature, hereinafter, referred to as a “first configuration”). The display area of the flexible display becomes a curved surface in a configuration that the flexible display is warped by an external force in the first configuration (e.g., a configuration having a finite radius of curvature, hereinafter, referred to as a “second configuration”). As illustrated in the drawing, information displayed in the second state may be visual information output on a curved surface. Such visual information is realized by independently controlling emission of sub-pixels (unit pixels) arranged in a matrix form. The sub-pixel denotes an elementary unit for representing one color. 
     The sub-pixel of the flexible display may be implemented by a semiconductor light emitting device. The present disclosure exemplarily illustrates a light emitting diode (LED) as a type of semiconductor light emitting device for converting current into light. The light emitting diode may have a small size to thereby serve as a sub-pixel even in the second configuration. 
     Hereinafter, a flexible display implemented using the light emitting diode will be described in more detail with reference to the accompanying drawings. 
       FIG. 2  is a partially enlarged view illustrating a portion “A” of  FIG. 1 , and  FIGS. 3A and 3B  are cross-sectional views taken along the lines “B-B” and “C-C” of  FIG. 2 ,  FIG. 4  is a conceptual view illustrating a flip chip type semiconductor light emitting device of  FIG. 3 , and  FIGS. 5A to 5C  are conceptual views illustrating various forms of realizing a color in association with a flip chip type semiconductor light emitting device. 
     Referring to  FIGS. 2, 3A, and 3B , a display device using a passive matrix (PM) type semiconductor light emitting device is used as a display device  100  using a semiconductor light emitting device. However, an example described hereinafter may also be applied to an active matrix (AM) type semiconductor light emitting device. 
     The display device  100  may include a first substrate  110 , a first electrode  120 , a conductive adhesive layer  130 , a second electrode  140 , and a plurality of semiconductor light emitting devices  150 . 
     The first substrate  110  may be a flexible substrate. The first substrate  110  may contain glass or polyimide (PI) to implement the flexible display device, for example. The first substrate  110  may alternatively be made of any material with an insulating property and flexibility such as polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and the like. In addition to, the first substrate  110  may be either one of transparent and non-transparent materials. 
     The first substrate  110  may be a wiring substrate provided with the first electrode  120 , and thus, the first electrode  120  may be placed on the first substrate  110 . 
     As illustrated, an insulating layer  160  may be disposed on the first substrate  110  on which the first electrode  120  is located, and an auxiliary electrode  170  may be disposed on the insulating layer  160 . Here, a configuration in which the insulating layer  160  is disposed on the first substrate  110  may be a single wiring substrate. More specifically, the insulating layer  160  may be made of a flexible insulating material, such as polyimide (PI), PET, and PEN, and may be formed integrally with the first substrate  110  to define a single substrate. 
     The auxiliary electrode  170  is an electrode that electrically connects the first electrode  120  and the semiconductor light emitting device  150 , and is disposed on the insulating layer  160  to correspond to a position of the first electrode  120 . For example, the auxiliary electrode  170  may have a dot-like shape and may be electrically connected to the first electrode  120  by an electrode hole  171  formed through the insulating layer  160 . The electrode hole  171  may be formed by filling a conductive material into a via hole. 
     Referring to the drawings, the conductive adhesive layer  130  may be formed on one surface of the insulating layer  160 , but the present disclosure may not be necessarily limited to this. For example, a layer serving as a specific function may be disposed between the insulating layer  160  and the conductive adhesive layer  130 , or the conductive adhesive layer  130  may be disposed on the first substrate  110  without the insulating layer  160 . The conductive adhesive layer  130  may perform the role of an insulating layer in a structure in which the conductive adhesive layer  130  is disposed on the first substrate  110 . 
     The conductive adhesive layer  130  may be a layer having adhesiveness and conductivity, and to this end, a conductive material and an adhesive material may be mixed for the conductive adhesive layer  130 . In addition, the conductive adhesive layer  130  may have flexibility to thereby enable a flexible function in the display device. 
     For such an example, the conductive adhesive layer  130  may be an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing conductive particles, and the like. The conductive adhesive layer  130  may allow electrical interconnection in a z-direction passing through the thickness thereof, but may be configured as a layer having electrical insulation in a horizontal x-y direction. Accordingly, the conductive adhesive layer  130  may be referred to as a z-axis conductive layer (hereinafter referred to as a ‘conductive adhesive layer’). 
     The anisotropic conductive film is a film in which an anisotropic conductive medium is mixed with an insulating base member. When heat and pressure are applied, only a specific portion has conductivity by the anisotropic conductive medium. Hereinafter, a description will be given of an example in which heat and pressure are both applied to the anisotropic conductive film, but other methods may alternatively be used to allow the anisotropic conductive film to partially have conductivity. Such methods may include applying either the heat or the pressure, a UV curing method, and the like. 
     In addition, the anisotropic conductive medium may be, for example, a conductive ball or a conductive particle. In this implementation, the anisotropic conductive film is a film in which conductive balls are mixed with an insulating base member. When heat and pressure are applied, only a specific portion of the anisotropic conductive film obtains conductivity by the conductive balls. The anisotropic conductive film may be a state of containing a plurality of particles each of which a core of a conductive material is coated with an insulating film made of a polymer material. At this time, a portion of the insulating film to which heat and pressure have been applied is broken to thereby obtain conductivity by the core. Here, the shape of the core may be deformed to form a layer in contact with the film in a thickness direction. As a more specific example, heat and pressure are applied to the entire anisotropic conductive film, and an electric connection in the z-axis direction is partially formed by a height difference of an object adhered by the anisotropic conductive film. 
     As another example, the anisotropic conductive film may be a state of containing a plurality of particles each of which the insulating core is coated with the conductive material. In this case, a portion of the conductive material to which the heat and pressure have been applied is deformed (stuck), and thus the portion has conductivity in the thickness direction of the film. As another example, the conductive material may penetrate through the insulating base member in the z-axis direction such that the film has conductivity in its thickness direction. In this case, the conductive material may have a sharp end portion. 
     As illustrated, the anisotropic conductive film may be a fixed array anisotropic conductive film (ACF) in which conductive balls are inserted into one surface of the insulating base member. More specifically, the insulating base member is made of a material having adhesiveness, and the conductive balls are concentrated on a bottom portion of the insulating base member. When heat and pressure are applied to the base member, the base member is deformed together with the conductive balls to thereby obtain conductivity in a perpendicular direction. 
     However, the present disclosure is not limited thereto. The anisotropic conductive film may alternatively be formed by randomly inserting conductive balls into the insulating base member, or may be configured in the form of double-ACF in which a plurality of layers are provided and the conductive balls are disposed in one of the layers. 
     The anisotropic conductive paste that is a combination of a paste and conductive balls may be a paste in which conductive balls are mixed with a base material having insulating property and adhesiveness. In addition, the solution containing conductive particles may be a solution in which conductive particles or nano particles are contained. 
     Referring to the drawing again, the second electrode  140  is located on the insulating layer  160  with being spaced apart from the auxiliary electrode  170 . In other words, the conductive adhesive layer  130  is disposed on the insulating layer  160  where the auxiliary electrode  170  and second electrode  140  are located. 
     When the conductive adhesive layer  130  is formed in a state that the auxiliary electrode  170  and second electrode  140  are located on the insulating layer  160 , and then heat and pressure are applied to connect the semiconductor light emitting device  150  in a flip chip form, the semiconductor light emitting device  150  is electrically connected to the first electrode  120  and second electrode  140 . 
     Referring to  FIG. 4 , the semiconductor light emitting device may be a flip chip type light emitting device. 
     For example, the semiconductor light emitting device includes a p-type electrode  156 , a p-type semiconductor layer  155  provided with the p-type electrode  156 , an active layer  154  disposed on the p-type semiconductor layer  155 , an n-type electrode  153  disposed on the active layer  154 , and an n-type electrode  152  disposed on the n-type semiconductor layer  153  with being spaced apart from the p-type electrode  156  in a horizontal direction. Here, the p-type electrode  156  may be electrically connected to the auxiliary electrode  170  by the conductive adhesive layer  130 , and the n-type electrode  152  may be electrically connected to the second electrode  140 . 
     Referring back to  FIGS. 2, 3A, and 3B , the auxiliary electrode  170  may be formed long in one direction, and one auxiliary electrode may be electrically connected to the plurality of semiconductor light emitting devices  150 . For example, p-type electrodes of the left and right semiconductor light emitting devices based on the auxiliary electrode may be electrically connected to one auxiliary electrode. 
     More specifically, the semiconductor light emitting device  150  is press-fitted into the conductive adhesive layer  130  by heat and pressure. Accordingly, only a portion between the p-type electrode  156  and auxiliary electrode  170  of the semiconductor light emitting device  150 , and a portion between the n-type electrode  152  and second electrode  140  of the semiconductor light emitting device  150  have conductivity, and the remaining portion does not have conductivity since there is no press-fitting of the semiconductor light emitting device. As such, the conductive adhesive layer  130  provides a mutual coupling as well as electrical connection between the semiconductor light emitting device  150  and the auxiliary electrode  170 , and between the semiconductor light emitting device  150  and the second electrode  140 . 
     In addition, the plurality of semiconductor light emitting devices  150  constitute a light emitting device array, and a phosphor layer  180  is formed on the light emitting device array. 
     The light emitting device array may include a plurality of semiconductor light emitting devices having different luminance values. Each of the semiconductor light emitting devices  150  constitutes a sub-pixel and is electrically connected to the first electrode  120 . For example, the first electrode  120  may be provided in plurality. The semiconductor light emitting devices, for example, may be arranged in several rows, and the semiconductor light emitting devices in each row may be electrically connected to one of the plurality of first electrodes. 
     In addition, since the semiconductor light emitting devices are connected in the form of a flip chip, the semiconductor light emitting devices grown on a transparent dielectric substrate can be used. The semiconductor light emitting devices may be, for example, nitride semiconductor light emitting devices. Since the semiconductor light emitting device  150  has excellent luminance, it can constitute an individual sub-pixel even though it is small in size. 
     As illustrated, a partition wall  190  may be formed between the semiconductor light emitting devices  150 . In this case, the partition wall  190  may perform the role of dividing individual sub-pixels from one another, and be formed as an integral body with the conductive adhesive layer  130 . For example, a base member of the anisotropic conductive film may form the partition wall when the semiconductor light emitting device  150  is inserted into the anisotropic conductive film. 
     When the base member of the anisotropic conductive film is black, the partition wall  190  may have reflective characteristics and also increase contrast even without an additional black insulator. 
     As another example, a reflective partition wall may be separately provided as the partition wall  190 . In this case, the partition wall  190  may include a black or white insulator according to the purpose of the display device. Reflectivity can be enhanced when the partition wall of the white insulator is used, and reflective characteristics can be obtained and contrast can be increased as well when the partition wall of the black insulator is used. 
     The phosphor layer  180  may be located at an outer surface of the semiconductor light emitting device  150 . For example, the semiconductor light emitting device  150  is a blue semiconductor light emitting device that emits blue (B) light, and the phosphor layer  180  performs the role of converting the blue (B) light into a color of a sub-pixel. The phosphor layer  180  may be a red phosphor layer  181  or a green phosphor layer  182  constituting individual pixels. 
     In other words, a red phosphor  181  capable of converting blue light into red (R) light may be stacked or disposed on the blue semiconductor light emitting device  151  at a location implementing a red sub-pixel, and a green phosphor  182  capable of converting blue light into green (G) light may be disposed on the blue semiconductor light emitting device  151  at a location implementing a green sub-pixel. In addition, only the blue semiconductor light emitting device  151  may be solely used at a location implementing a blue sub-pixel. In this case, the red (R), green (G), and blue (B) sub-pixels may implement one pixel. More specifically, one color phosphor may be disposed along each line of the first electrode  120 . Accordingly, one line on the first electrode  120  may be an electrode controlling one color. In other words, red (R), green (B), and blue (B) may be sequentially arranged along the second electrode  140 , thereby implementing sub-pixels. 
     However, the present disclosure may not be necessarily limited to this, and the semiconductor light emitting device  150  may be combined with a quantum dot (QD) instead of the phosphor to implement red (R), green (G), and blue (B) sub-pixels. 
     In addition, a black matrix  191  may be disposed between each of the phosphor layers to enhance contrast. In other words, the black matrix  191  can enhance the contrast of luminance. 
     However, the present disclosure may not be necessarily limited to this, and another structure for implementing blue, red, and green lights may be also applicable thereto. 
     Referring to  FIG. 5A , each of the semiconductor light emitting devices  150  may be implemented as a high-power light emitting device that emits various light including blue light in a manner that gallium nitride (GaN) is mostly used, and indium (In) and or aluminum (Al) are added thereto. 
     In this case, the semiconductor light emitting devices  150  may be red, green, and blue semiconductor light emitting devices, respectively, to implement each sub-pixel. For instance, red, green, and blue semiconductor light emitting devices (R, G, B) are alternately disposed, and red, green, and blue sub-pixels implement one pixel by the red, green, and blue semiconductor light emitting devices, thereby achieving a full color display. 
     Referring to  FIG. 5B , the semiconductor light emitting device may have a white light emitting device (W) provided with a yellow phosphor layer for each device. In this case, a red phosphor layer  181 , a green phosphor layer  182 , and a blue phosphor layer  183  may be provided on the white light emitting device (VV) to implement a sub-pixel. Further, the sub-pixel may be formed by using a color filter repeated with red, green, and blue on the white light emitting device (W). 
     Referring to  FIG. 5C , a structure in which a red phosphor layer  181 , a green phosphor layer  182 , and a blue phosphor layer  183  are provided on a ultra violet light emitting device (UV) is also available. In this manner, the semiconductor light emitting device can be used over the entire region up to ultra violet (UV) as well as visible light, and can be extensively used in the form of a semiconductor light emitting device in which ultra violet (UV) is used as an excitation source. 
     Returning back to the implementation, the semiconductor light emitting device  150  is located on the conductive adhesive layer  130  to configure a sub-pixel in the display device. The semiconductor light emitting device  150  has excellent luminance to thereby configure an individual sub-pixel even it is small size. The size of the individual semiconductor light emitting device  150  may be less than 80 μm in the length of one side thereof, and may be a rectangular or square shaped device. In the case of a rectangular shaped device, its size may be less than 20×80 μm. 
     Further, even when a square shaped semiconductor light emitting device  150  with the length of one side of  10 pm is used as a sub-pixel, it will exhibit sufficient brightness for implementing a display device. Taking a rectangular pixel as an example, when one side of a sub-pixel is  600 pm and the other side thereof is 300 μm, a distance between the semiconductor light emitting devices is relatively sufficiently large. Accordingly, a flexible display device having an HD image quality can be achieved. 
     A display device using the semiconductor light emitting device described above may be manufactured by a new type of manufacturing method. Hereinafter, the manufacturing method will be described with reference to  FIG. 6 . 
       FIG. 6  is a cross-sectional view illustrating a method of manufacturing a display device using a semiconductor light emitting device according to the present disclosure. 
     Referring to the drawing, first, a conductive adhesive layer  130  is formed on an insulating layer  160  where an auxiliary electrode  170  and a second electrode  140  are located. The insulating layer  160  is disposed on a first substrate  110  to form one substrate (or wiring substrate), and a first electrode  120 , the auxiliary electrode  170 , and the second electrode  140  are disposed at the wiring substrate. In this case, the first electrode  120  and second electrode  140  may be disposed in an orthogonal direction to each other. In addition, the first substrate  110  and the insulating layer  160  may each contain glass or polyimide (PI) to implement a flexible display device. 
     The conductive adhesive layer  130  may be implemented by an anisotropic conductive film, for example. To this end, an anisotropic conductive film may be coated on the substrate where the insulating layer  160  is located. 
     Next, a second substrate  112  having a plurality of semiconductor light emitting devices  150  that correspond to locations of the auxiliary electrodes  170  and second electrodes  140  and constitute individual pixels is disposed such that the semiconductor light emitting devices  150  face the auxiliary electrodes  170  and the second electrodes  140 . 
     In this case, the second substrate  112 , which is a growth substrate for growing the semiconductor light emitting device  150 , may be a sapphire substrate or silicon substrate. 
     The semiconductor light emitting device may have a gap and size capable of implementing a display device when formed in the wafer unit, thereby being effectively used for the display device. 
     Next, the wiring substrate and the second substrate  112  are thermally compressed together. For example, the wiring substrate and second substrate  112  may be thermally compressed to each other by using an ACF press head. The wiring substrate and second substrate  112  are bonded together by the thermal compression. Only portions between the semiconductor light emitting device  150  and the auxiliary electrode  170 , and between the semiconductor light emitting device  150  and the second electrode  140  may have conductivity due to the characteristics of an anisotropic conductive film having conductivity by thermal compression, thereby allowing the electrodes and the semiconductor light emitting device  150  to be electrically connected to each other. Here, the semiconductor light emitting device  150  may be inserted into the anisotropic conductive film to thereby define a partition wall between the semiconductor light emitting devices  150 . 
     Next, the second substrate  112  is removed. For example, the second substrate  112  may be removed using a laser lift-off (LLO) method or a chemical lift-off (CLO) method. 
     Finally, the second substrate  112  is removed to expose the semiconductor light emitting devices  150  to the outside. Silicon oxide (SiOx) or the like may be coated on the wiring substrate coupled to the semiconductor light emitting device  150  to form a transparent insulating layer (not shown). 
     In addition, a step (or process) of forming a phosphor layer on one surface of the semiconductor light emitting device  150  may be further included. For example, the semiconductor light emitting device  150  may be a blue semiconductor light emitting device that emits blue (B) light, and a red or green phosphor for converting the blue (B) light into the color of the sub-pixel may form a layer on one surface of the blue semiconductor light emitting device. 
     The manufacturing method or structure of the display device using the semiconductor light emitting device described above may be modified in various forms. For such an example, a vertical semiconductor type light emitting device may also be employed in the aforementioned display device. Hereinafter, the vertical structure will be described with reference to  FIGS. 5 and 6 . 
     Further, according to the following modified example or implementation, the same or similar reference numerals are designated to the same or similar configurations to the previous example, and a description thereof will be substituted by the earlier description. 
       FIG. 7  is a perspective view illustrating a display device using a semiconductor light emitting device according to another implementation of the present disclosure,  FIG. 8  is a cross-sectional view taken along the line “D-D” of  FIG. 7 , and  FIG. 9  is a conceptual view illustrating a vertical type semiconductor light emitting device of  FIG. 8 . 
     Referring to the drawings, the display device may be a display device using a passive matrix (PM) type of a vertical semiconductor light emitting device. 
     The display device may include a substrate  210 , a first electrode  220 , a conductive adhesive layer  230 , a second electrode  240 , and a plurality of semiconductor light emitting devices  250 . 
     The substrate  210 , which is a wiring substrate on which the first electrode  220  is disposed, may include polyimide (PI) to implement a flexible display device. In addition to, any material may be used if it is an insulating and flexible material. 
     The first electrode  220  may be located on the substrate  210  and formed in a shape of a long bar in one direction. The first electrode  220  may serve as a data electrode. 
     The conductive adhesive layer  230  is formed on the substrate  210  where the first electrode  220  is located. Similar to the display device in which a flip chip type light emitting device is employed, the conductive adhesive layer  230  may be an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing conductive particles, or the like. However, this implementation illustrates a case in which the conductive adhesive layer  230  is implemented by an anisotropic conductive film. 
     When an anisotropic conductive film is disposed in a state that the first electrode  220  is located on the substrate  210 , and then heat and pressure are applied to connect the semiconductor light emitting device  250 , the semiconductor light emitting device  250  is electrically connected to the first electrode  220 . Here, the semiconductor light emitting device  250  may be, preferably, disposed on the first electrode  220 . 
     The electrical connection is achieved when heat and pressure are applied because an anisotropic conductive film partially has conductivity in the thickness direction, as described above. Accordingly, the anisotropic conductive film is divided into a portion having conductivity and a portion having no conductivity in the thickness direction thereof. 
     Further, the anisotropic conductive film contains an adhesive component, and thus the conductive adhesive layer  230  provides not only a mechanical coupling but also an electrical connection between the semiconductor light emitting device  250  and the first electrode  220 . 
     In this manner, the semiconductor light emitting device  250  is placed on the conductive adhesive layer  230  to thereby configure a separate sub-pixel in the display device. Since the semiconductor light emitting device  250  has excellent luminance, it can constitute an individual sub-pixel even though it is small in size. The size of the individual semiconductor light emitting device  250  may be less than 80 μm in the length of one side thereof, and may be a rectangular or square shaped device. In the case of a rectangular shaped device, its size may be less than 20×80 μm. 
     The semiconductor light emitting device  250  may be a vertical structure. 
     A plurality of second electrodes  240  that are disposed in a direction crossing a lengthwise direction of the first electrode  220  and are electrically connected to the vertical semiconductor light emitting device  250  may be located between vertical semiconductor light emitting devices. 
     Referring to  FIG. 9 , the vertical type semiconductor light emitting device includes a p-type electrode  256 , a p-type semiconductor layer  255  formed on the p-type electrode  256 , an active layer  254  formed on the p-type semiconductor layer  255 , an n-type semiconductor layer  253  formed on the active layer  254 , and an n-type electrode  252  formed on the n-type semiconductor layer  253 . Here, the p-type electrode  256  located at the bottom may be electrically connected to the first electrode  220  by the conductive adhesive layer  230 , and the n-type electrode  252  located at the top may be electrically connected to the second electrode  240  to be described hereinafter. The electrodes may be disposed in an up-and-down direction in the vertical type semiconductor light emitting device  250  to thereby provide a great advantage of reducing the chip size. 
     Referring back to  FIG. 8 , a phosphor layer  280  may be formed on one surface of the semiconductor light emitting device  250 . For example, the semiconductor light emitting device  250  is a blue semiconductor light emitting device  251  that emits blue (B) light, and the phosphor layer  280  for converting the blue (B) light into the color of the sub-pixel may be provided thereon. In this case, the phosphor layer  280  may be a red phosphor  281  and a green phosphor  282  constituting individual pixels. 
     In other words, a red phosphor  281  capable of converting blue light into red (R) light may be disposed on the blue semiconductor light emitting device  251  at a location implementing a red sub-pixel, and a green phosphor  282  capable of converting blue light into green (G) light may be disposed on the blue semiconductor light emitting device  251  at a location implementing a green sub-pixel. In addition, only the blue semiconductor light emitting device  251  may be solely used at a location implementing a blue sub-pixel. In this case, the red (R), green (G), and blue (B) sub-pixels may implement one pixel. 
     However, the present disclosure may not be necessarily limited to this, and other structures for implementing blue, red, and green may be also applicable as described above in the display device in which a flip chip type light emitting device is employed. 
     In this implementation, the second electrode  240  is located between the semiconductor light emitting devices  250 , and is electrically connected to the semiconductor light emitting devices  250 . For example, the semiconductor light emitting devices  250  may be disposed in a plurality of rows, and the second electrode  240  may be disposed between the rows of the semiconductor light emitting devices  250 . 
     Since a distance between the semiconductor light emitting devices  250  constituting individual pixels is sufficiently large, the second electrode  240  may be located between the semiconductor light emitting devices  250 . 
     The second electrode  240  may be formed as a bar-shaped electrode elongated in one direction and disposed in a direction perpendicular to the first electrode. 
     Further, the second electrode  240  may be electrically connected to the semiconductor light emitting device  250  by a connecting electrode that protrudes from the second electrode  240 . More specifically, the connecting electrode may be an n-type electrode of the semiconductor light emitting device  250 . For example, the n-type electrode is formed as an ohmic electrode for ohmic contact, and the second electrode covers at least part of the ohmic electrode by printing or deposition. Accordingly, the second electrode  240  may be electrically connected to the n-type electrode of the semiconductor light emitting device  250 . 
     As illustrated, the second electrode  240  may be located on the conductive adhesive layer  230 . In some implementations, a transparent insulating layer (not shown) containing silicon oxide (SiOx) may be formed on the substrate  210  provided with the semiconductor light emitting device  250 . When the transparent insulating layer is formed and then the second electrode  240  is placed thereon, the second electrode  240  may be located on the transparent insulating layer. In addition, the second electrode  240  may be spaced apart from the conductive adhesive layer  230  or the transparent insulating layer. 
     If a transparent electrode such as indium tin oxide (ITO) is used to locate the second electrode  240  on the semiconductor light emitting device  250 , the ITO material has bad adhesiveness with an n-type semiconductor. In the present disclosure, as the second electrode  240  is placed between the semiconductor light emitting devices  250 , a transparent electrode such as an ITO is not required. Therefore, an n-type semiconductor layer and a conductive material having good adhesiveness may be used as a horizontal electrode without being restricted by the selection of a transparent material, thereby enhancing the light extraction efficiency. 
     As illustrated, a partition wall  290  may be disposed between the semiconductor light emitting devices  250 . In other words, the partition wall  290  may be disposed between the vertical semiconductor light emitting devices  250  to isolate the semiconductor light emitting devices  250  constituting individual pixels. In this case, the partition wall  290  may serve to divide individual sub-pixels from one another, and be formed as an integral body with the conductive adhesive layer  230 . For example, a base member of the anisotropic conductive film may define the partition wall when the semiconductor light emitting device  250  is inserted into the anisotropic conductive film. 
     When the base member of the anisotropic conductive film is black, the partition wall  290  may have reflective characteristics and increase contrast as well even without an additional black insulator. 
     As another example, a reflective partition wall may be separately provided as the partition wall  290 . In this case, the partition wall  290  may include a black or white insulator according to the purpose of the display device. 
     If the second electrode  240  is directly located on the conductive adhesive layer  230  between the semiconductor light emitting devices  250 , the partition wall  290  may be located between the semiconductor light emitting device  250  and the second electrode  240 . Accordingly, individual sub-pixels may be configured even with a small size using the semiconductor light emitting device  250 , and a distance between the semiconductor light emitting devices  250  may be relatively sufficiently large to place the second electrode  240  between the semiconductor light emitting devices  250 , thereby achieving a flexible display device having a HD image quality. 
     Further, according to the drawing, a black matrix  291  may be disposed between each of the phosphor layers to enhance contrast. In other words, the black matrix  291  can enhance the contrast of luminance. 
     In this manner, the semiconductor light emitting device  250  is placed on the conductive adhesive layer  230  to thereby configure a separate sub-pixel in the display device. Since the semiconductor light emitting device  250  has excellent luminance, it can constitute an individual sub-pixel even though it is small in size. As a result, a full color display in which the sub-pixels of red (R), green (G), and blue (B) implement one pixel by the semiconductor light emitting device can be achieved. 
     Meanwhile, the semiconductor light emitting devices provided in the display device described with reference to  FIGS. 1 to 9  are formed on a wafer. In detail, conductive semiconductor layers are sequentially disposed on a wafer to fabricate individual semiconductor light emitting devices through an isolation process and a mesa process. Hereinafter, a method of fabricating the flip chip type semiconductor light emitting device described with reference to  FIG. 4  will be described in detail. However, the present disclosure may be applied not only to the flip chip type semiconductor light emitting device, but also to the vertical type semiconductor light emitting device described with reference to  FIG. 9 . 
     In detail, a growth substrate (wafer) may be made of a light transmissive material, for example, one of sapphire (Al2O3), GaN, ZnO, and AlO, but the present disclosure is not limited thereto. In addition, the growth substrate may be made of a material suitable for growing a semiconductor material, namely, a carrier wafer. The growth substrate may also be formed of a material having high thermal conductivity. The growth substrate may use at least one of a SiC substrate having higher thermal conductivity than the sapphire (Al2O3) substrate, Si, GaAs, GaP, InP, and Ga2O3, in addition to a conductive substrate or an insulating substrate. 
     Next, at least portions or parts of a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer are removed to form a plurality of semiconductor light emitting devices. 
     More specifically, isolation is performed such that the plurality of light emitting devices form an array with an epi-chip. That is, the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer are etched in a vertical direction to form a plurality of semiconductor light emitting devices. 
     In this step, a mesa process in which the active layer and the second conductive semiconductor layer are partially removed in the vertical direction such that the first conductive semiconductor layer is exposed to the outside is performed, and then an isolation process in which the first conductive semiconductor layer is etched to form a plurality of semiconductor light emitting device arrays is performed. Here, the semiconductor light emitting device may be isolated to a size of 100 μm or less. 
     Next, a second conductive electrode (or p-type electrode) is formed on one surface of the second conductive semiconductor layer. The second conductive electrode may be formed by a deposition method such as sputtering, but the present disclosure is not limited thereto. However, when the first conductive semiconductor layer and the second conductive semiconductor layer are an n-type semiconductor layer and a p-type semiconductor layer, respectively, the second conductive electrode may be an n-type electrode. 
     Each of the first and second conductive semiconductor layers and the active layer has a shape in which crystal lattices having a predetermined structure are repeated. Crystal lattices respectively constituting the first and second conductive semiconductor layers and the active layer may have different structures. For this reason, at least one of the first conductive semiconductor layer, the second conductive semiconductor layer, and the active layer may be damaged or broken during the isolation or mesa process. In particular, when even a portion of the active layer is damaged, the semiconductor light emitting device loses its light emitting ability. 
     Conventionally, in order to solve the problem of semiconductor light emitting device damage with a certain probability, a plurality of semiconductor light emitting devices are disposed for each sub-pixel. Accordingly, even if one of the semiconductor light emitting devices included in a sub-pixel loses light emitting ability, other semiconductor light emitting devices can perform the function of the sub-pixel. 
     However, this solution is not suitable for a high-resolution display in which a distance between the semiconductor light emitting devices is very small. The present disclosure provides a structure for minimizing a distance between semiconductor light emitting devices while preventing the semiconductor light emitting devices from being damaged with a certain probability. 
     Hereinafter, a structure of the semiconductor light emitting device (or element) according to the present disclosure will be described in detail. 
       FIG. 10  is a cross-sectional view illustrating a semiconductor light emitting device according to one implementation of the present disclosure, and  FIGS. 11 and 12  are planar views illustrating a semiconductor light emitting device according to the present disclosure. 
     Referring to  FIG. 10 , a semiconductor light emitting device  300  according to one implementation of the present disclosure includes a first conductive semiconductor layer (or first conductive-type semiconductor layer)  353 , a second conductive semiconductor layer (or second conductive-type semiconductor layer)  355  formed on the first conductive semiconductor layer  353 , and an active layer  354  disposed between the first and second conductive semiconductor layers  353  and  355 . 
     Here, the second conductive semiconductor layer  355  is provided in plurality on the first conductive semiconductor layer  353 , such that a plurality of active layers that are spaced apart from one another are formed on each of the plurality of semiconductor light emitting devices. 
     That is, the plurality of second conductive semiconductor layers spaced apart from each another are disposed on the first conductive semiconductor layer  353 . Each of the active layers is formed at a position where the first conductive semiconductor layer  353  and each of the plurality of second conductive semiconductor layers overlap. Accordingly, one semiconductor light emitting device includes a plurality of second conductive semiconductor layers and a plurality of active layers. 
     A first conductive electrode  352  is formed on one surface of the first conductive semiconductor layer  353 , and second conductive electrodes  356 a and  356   b  are disposed on the plurality of second conductive semiconductor layers  355 , respectively. This allows a voltage to be applied to each of the plurality of second conductive semiconductor layers  355 . A structure for applying a voltage to each of the plurality of second conductive semiconductor layers will be described later. 
     The semiconductor light emitting device according to the present disclosure may be implemented in various shapes. In detail, as illustrated in  FIG. 10 , the first and second conductive semiconductor layers may be alternately disposed along one direction. In this case, the semiconductor light emitting device has a bar shape. 
     Alternatively, referring to  FIG. 11 , a semiconductor light emitting device  400  may have a shape with equal length and width, or a shape with little difference in length and width. A first conductive electrode  452  is disposed on one surface of a first conductive semiconductor layer  453 . A second conductive semiconductor layer  455  may be defined in a region of the one surface except a region in which the first conductive electrode  452  is disposed. Since an active layer is formed in a region where the first conductive semiconductor layer  453  and the second conductive semiconductor layer  455  overlap, an overlapping area of the first conductive semiconductor layer  453  and the second conductive semiconductor layer  455  should be maximized. 
     Meanwhile, the second conductive semiconductor layers are not necessarily two in number. Three or more second conductive semiconductor layers may be defined in one semiconductor light emitting device. For example, referring to  FIG. 12 , three second conductive semiconductor layers  555   a,    555   b,  and  555   c  may be formed on one surface of a first conductive semiconductor layer  553  included in a semiconductor light emitting device  500 . Different second conductive electrodes  556   a,    556   b,  and  556   c  may be disposed on the three second conductive semiconductor layers  555   a,    555   b,  and  555   c,  respectively. 
     As described above, the semiconductor light emitting device according to the present disclosure includes a plurality of second conductive semiconductor layers and a plurality of active layers. Accordingly, even when any one of the active layers that are spaced apart from each other is damaged, the remaining active layer maintains its light emitting ability. Thus, in the present disclosure, a problem of occurrence of semiconductor light emitting device damage or failure with a certain probability or possibility can be solved without arranging a plurality of semiconductor light emitting devices in a single sub-pixel. 
     Hereinafter, a structure for applying a voltage to the semiconductor light emitting device according to the present disclosure will be described. 
       FIG. 13  is a conceptual view illustrating an example state in which semiconductor light emitting devices and wiring electrodes are connected to each other. 
     A plurality of electrode lines are disposed on a substrate. In detail, a first electrode line that is electrically connected to one of first and second conductive electrodes, and a second electrode line that is electrically connected to the remaining one of the first and second conductive electrodes are disposed on the substrate. In this specification, an example in which the first electrode line is connected to the second conductive electrode, and the second electrode line is connected to the first conductive electrode will be described, but the present disclosure is not limited thereto. 
     A first electrode line  320  and a second electrode line  340  are formed at a substrate illustrated in  FIG. 13 . The first and second electrode lines  320  and  340  are formed on different planes. In detail, the first electrode line  320  is disposed below the second electrode line  340 . 
       FIG. 13  illustrates a state in which the semiconductor light emitting device described with reference to  FIGS. 1 to 9 , and the semiconductor light emitting devices described with reference to  FIGS. 10 and 12  are connected to wiring electrodes. The semiconductor light emitting device described with reference to  FIGS. 1 to 9  includes a first conductive electrode  252  and a second conductive electrode  256 . The first conductive electrode  252  is electrically connected to the second electrode line  340  through an auxiliary electrode  342 , and the second conductive electrode  256  is electrically connected to the first electrode line  320  through an auxiliary electrode  370  and a via hole  371 . 
     Meanwhile, semiconductor light emitting devices according to one implementation of the present disclosure each include a plurality of second conductive semiconductor layers, and second conductive electrodes are formed on the second conductive semiconductor layers, respectively. Each of the second conductive electrodes is electrically connected to one of a plurality of electrode lines. 
     Referring to the semiconductor light emitting device  300  described with reference to  FIG. 10 , the plurality of second conductive semiconductor layers are electrically connected to different electrode lines. In detail, one ( 356   a ) of a plurality of second conductive electrodes  356   a  and  356   b  included in the semiconductor light emitting device  300  is electrically connected to one ( 320   a ) of a plurality of first electrode lines  320   a  and  320   b  through an auxiliary electrode  370   a  and a first via hole  371   a.  The remaining one ( 356   b ) of the plurality of second conductive electrodes  356   a  and  356   b  is electrically connected to the remaining one ( 320   b ) of the plurality of first electrode lines  320   a  and  320   b  through an auxiliary electrode  370   b  and a second via hole  371   b.  Meanwhile, one (or single) first conductive electrode  352  is electrically connected to the second electrode line  340  through an auxiliary electrode  342 . 
     Referring to the semiconductor light emitting device  400  described with reference to  FIG. 11 , the plurality of second conductive semiconductor layers are electrically connected to different electrode lines. In detail, one ( 456   a ) of a plurality of second conductive electrodes  456   a  and  456   b  included in the semiconductor light emitting device  400  is electrically connected to one ( 320   a ) of a plurality of electrode lines  320   a  and  320   b  through an auxiliary electrode  370   a  and a first via hole  371   a.  The remaining one ( 456   b ) of the plurality of second conductive electrodes  456   a  and  456   b  is electrically connected to the remaining one ( 320   b ) of the plurality of first electrode lines  320   a  and  320   b  through an auxiliary electrode  370   b  and a second via hole  371   b.  Meanwhile, one first conductive electrode  452  is electrically connected to the second electrode line  340  through an auxiliary electrode  342 . 
     As such, in the present disclosure, the plurality of second conductive semiconductor layers are electrically connected to different electrode lines, so that even when one of the plurality of active layers provided at the semiconductor light emitting device is damaged, light can be emitted through the remaining active layer. 
     Meanwhile, although not illustrated, a plurality of second conductive semiconductor layers provided in a single semiconductor light emitting device may be connected in parallel to the same electrode line. In this case, when a voltage is applied to first and second electrode lines, the magnitude of current flowing through the entire semiconductor light emitting device is kept constant all the time. Taking the semiconductor light emitting device described with reference to  FIG. 10  as an example, when a voltage is applied to the first and second electrode lines in a state that both of the active layers are not damaged, current flowing through the entire semiconductor light emitting device is branched or diverged into two second conductive semiconductor layers. Assuming that the amount of light required by one semiconductor light emitting device is  100 , the amount of light emitted from each of the two active layers is  50 . 
     If one of the two active layers is damaged, current flowing through the entire semiconductor light emitting device flows only through a conductive semiconductor layer that overlaps an undamaged active layer of the two second conductive semiconductor layers. Assuming that the amount of light required by one semiconductor light emitting device is  100 , the amount of light emitted from the undamaged active layer is  100 . 
     Thus, in the present disclosure, the original light quantity of the semiconductor light emitting device can be maintained without a separate control and repair when a part of the plurality of active layers is damaged. 
     Referring to  FIG. 14 , the flip chip type semiconductor light emitting device described above may be implemented in various shapes. In detail, a semiconductor light emitting device may be formed in a rectangular shape ((a), (c), and (e)), such that p-type and n-type electrodes may be formed within a range that can maximize the use of a rectangular plane. However, the present disclosure is not limited thereto, and the semiconductor light emitting device may be implemented in other various shapes, such as a bar shape (b), a hexagonal shape (d), and a circular shape (f). In  FIG. 14 , a first conductive semiconductor layer is illustrated as an n-type semiconductor layer, and a second conductive semiconductor layer is illustrated as a p-type semiconductor layer. However, the present disclosure is not limited thereto. 
     Meanwhile, the present disclosure may also be applied to a vertical type semiconductor light emitting device. Hereinafter, a vertical type semiconductor light emitting device including a plurality of active layers will be described. 
       FIG. 15  is a conceptual view illustrating a vertical type semiconductor light emitting device including a plurality of active layers. 
     Referring to  FIG. 15 , a plurality of second conductive semiconductor layers  655   a  and  655   b  may be disposed at one of both surfaces of a first conductive semiconductor layer  653 , and a first conductive electrode  652  may be disposed at the remaining one surface of the both surfaces of the first conductive semiconductor layer  653  that is different from the one surface at which the plurality of second conductive semiconductor layers  655   a  and  655   b  are disposed. Accordingly, the first conductive electrode  652  and a plurality of second conductive electrodes  656   a  and  656   b  are disposed to face opposite directions. 
     Accordingly, a plurality of active layers  654   a  and  654   b  are defined in one vertical type semiconductor light emitting device, and even when one of the plurality of active layers is damaged, light is emitted through the remaining active layer. 
     The vertical type semiconductor light emitting device may be formed in a circular shape as shown in (b) of  FIG. 15 , or in a rectangular shape as shown in (c) of  FIG. 15 . A plurality of p-type electrodes may be disposed at one surface of the semiconductor light emitting device. In  FIG. 15 , a first conductive semiconductor layer is illustrated as an n-type semiconductor layer, and a second conductive semiconductor layer is illustrated as a p-type semiconductor layer. However, the present disclosure is not limited thereto. 
     As such, the semiconductor light emitting device according to the present disclosure includes a plurality of light emitting regions, light emitting ability of the semiconductor light emitting device can be maintained even when one of the light emitting regions loses its light emitting ability. Accordingly, there is no need to dispose a plurality of semiconductor light emitting devices for each sub-pixel in preparation for semiconductor light emitting device damage. Thus, a high-resolution display with a very small distance between semiconductor light emitting devices can be achieved. 
     The aforementioned display device using the semiconductor light emitting devices are not limited to the configuration and the method of the implementations described above, but the implementations may be configured such that all or some of the implementations are selectively combined so that various modifications can be made.