Source: https://patents.google.com/patent/KR20170048066A/en
Timestamp: 2020-01-29 14:09:30
Document Index: 559556293

Matched Legal Cases: ['art 1162', 'art 1162', 'art 1161', 'art 2162', 'art 2161', 'art 2162']

KR20170048066A - Display device using semiconductor light emitting device and method for manufacturing the same - Google Patents
Display device using semiconductor light emitting device and method for manufacturing the same Download PDF
KR20170048066A
KR20170048066A KR1020150148965A KR20150148965A KR20170048066A KR 20170048066 A KR20170048066 A KR 20170048066A KR 1020150148965 A KR1020150148965 A KR 1020150148965A KR 20150148965 A KR20150148965 A KR 20150148965A KR 20170048066 A KR20170048066 A KR 20170048066A
KR1020150148965A
여환국
2015-10-26 Application filed by 엘지전자 주식회사 filed Critical 엘지전자 주식회사
2015-10-26 Priority to KR1020150148965A priority Critical patent/KR20170048066A/en
2017-05-08 Publication of KR20170048066A publication Critical patent/KR20170048066A/en
The present invention relates to a display device, and more particularly, to a display device using a semiconductor light emitting device. At least one of the semiconductor light emitting devices may include a first conductive type semiconductor layer, a second conductive type semiconductor layer overlapping the first conductive type semiconductor layer, and a second conductive type semiconductor layer overlapping the first conductive type semiconductor layer, And a second conductive type semiconductor layer, wherein the second conductive type semiconductor layer has a recessed groove formed in at least a part of the second conductive type semiconductor layer, Type semiconductor layer and has a side wall part surrounding the bottom part.
TECHNICAL FIELD [0001] The present invention relates to a display device using a semiconductor light emitting device, and a method of manufacturing the same. [0002]
The present invention relates to a display device and a method of manufacturing the same, and more particularly to a flexible display device using a semiconductor light emitting element.
In recent years, display devices having excellent characteristics such as a thin shape and a flexible shape in the field of display technology have been developed. On the other hand, major displays that are commercialized today are represented by LCD (Liguid Crystal Display) and AMOLED (Active Matrix Organic Light Emitting Diodes).
However, in the case of LCD, there is a problem that the reaction time is not fast and the implementation of flexible is difficult. In the case of AMOLED, there is a weak point that the lifetime is short, the mass production yield is not good, and the degree of flexible is weak.
Light emitting diodes (LEDs) are well-known semiconductor light emitting devices that convert current into light. In 1962, red LEDs using GaAsP compound semiconductors were commercialized, Has been used as a light source for a display image of an electronic device including a communication device. Accordingly, a method of solving the above problems by implementing a flexible display using the semiconductor light emitting device can be presented.
The flexible display using the semiconductor light emitting device may need to improve the luminous efficiency of the semiconductor light emitting device. In order to improve the luminous efficiency, the portion of the light-emitting surface covered with the wiring electrode connected to the semiconductor light-emitting device must be minimized. On the other hand, a contact surface at which the wiring electrode is in electrical contact with the semiconductor light emitting element should be maximally secured. Accordingly, the present invention proposes a mechanism capable of reducing the portion where the light-emitting surface is covered while securing the contact surface.
It is an object of the present invention to provide a structure for improving luminance in a display device and a method of manufacturing the same.
Another object of the present invention is to lower the operating voltage of the semiconductor light emitting devices and improve the light emitting efficiency.
The display device according to the present invention is a display device including a plurality of semiconductor light emitting devices, wherein at least one of the semiconductor light emitting devices includes a first conductivity type semiconductor layer, 2 conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer. A recessed groove is formed in at least a part of the second conductive type semiconductor layer, and the recessed groove has a bottom portion and a side wall portion formed along an edge of the second conductive type semiconductor layer and surrounding the bottom portion.
In an embodiment, at least a part of the wiring electrode for supplying an electric signal to the semiconductor light emitting elements may be disposed in the recessed groove. The wiring electrode may be formed to cover at least a part of the side wall portion. The side wall portion may have a pair of side walls parallel to each other, and the wiring electrode may be formed so as to cover one of the pair of side walls and not cover the other.
In one embodiment, the first conductivity type semiconductor layer is a P-type GaN layer, the second conductivity type semiconductor layer is an N-type GaN layer, and the recess groove is a portion where at least a part of the N-type Gan layer is etched .
In one embodiment of the present invention, at least one of the semiconductor light emitting devices further includes an undoped semiconductor layer formed to cover the second conductive type semiconductor layer, Type semiconductor layer to the first conductive-type semiconductive layer.
In an embodiment, the surface of the bottom portion may have irregularities. The side wall portion may be inclined with respect to a direction perpendicular to the bottom portion.
According to another aspect of the present invention, there is provided a semiconductor light emitting device including: a first conductivity type semiconductor layer; a second conductivity type semiconductor layer that overlaps with the first conductivity type semiconductor layer; Wherein a recessed groove is formed in at least a part of the second conductive type semiconductor layer, the recessed groove is formed along a bottom portion and an edge of the first conductive type semiconductor layer, And a side wall portion.
According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor light emitting device, comprising: sequentially growing a second conductivity type semiconductor layer, an active layer and a first conductivity type semiconductor layer on a substrate so that the first conductivity type semiconductor layer, Isolating the semiconductor light emitting devices on the substrate by etching the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer; separating the semiconductor light emitting device from the substrate; Forming a recessed groove in the conductive type semiconductor layer, and electrically connecting the second conductive type semiconductor layer formed with the recessed groove to the wiring electrode. .
In the display device according to the present invention, the contact area between the wiring electrodes and the semiconductor light emitting elements can be widened by the well structure. Accordingly, the operating voltage of the semiconductor light emitting devices can be lowered and at the same time, the light extraction efficiency can be improved. Therefore, the brightness of the display device can be greatly improved.
In addition, according to the present invention, since the recessed grooves are formed on one surface of the semiconductor light emitting devices, the luminance improvement of the display device can be realized despite the simple manufacturing method.
In addition, in the present invention, it is possible to realize a wiring electrode connection structure that can ensure reliability even in the process margin of a semiconductor light emitting device of a micro unit size.
1 is a conceptual diagram showing an embodiment of a display device using the semiconductor light emitting device of the present invention.
Fig. 2 is a partially enlarged view of part A of Fig. 1, and Figs. 3a and 3b are cross-sectional views taken along line BB and CC of Fig.
4 is a conceptual diagram showing a flip chip type semiconductor light emitting device of FIG.
FIGS. 5A to 5C are conceptual diagrams showing various forms of implementing a color in relation to a flip chip type semiconductor light emitting device.
6 is a cross-sectional view illustrating a method of manufacturing a display device using the semiconductor light emitting device of the present invention.
7 is a perspective view showing another embodiment of a display device using the semiconductor light emitting device of the present invention.
8 is a cross-sectional view taken along line DD of FIG.
9 is a conceptual diagram showing a vertical semiconductor light emitting device of FIG.
Fig. 10 is an enlarged view of a portion A in Fig. 1 for explaining another embodiment of the present invention to which a semiconductor light emitting element having a new structure is applied.
11 is a cross-sectional view taken along the line EE of Fig.
12 is a cross-sectional view taken along the line FF of Fig.
13 is a conceptual diagram showing a semiconductor light emitting device having a novel structure of FIG.
FIG. 14 is a current flow chart comparing the display device of FIG. 10 with a conventional display device.
FIG. 15A is a photograph of a product of the semiconductor light emitting device of FIG. 13, and FIG. 15B is a plan view showing the well structure and the wiring electrode of the present invention.
16A, 16B, 16C, 16D, 17A, 17B, 17, and 17D are cross-sectional views illustrating a method of manufacturing a display device using the semiconductor light emitting device of the present invention.
FIG. 18 is a cross-sectional view for explaining another embodiment of the present invention, and FIG. 19 is a conceptual diagram showing a semiconductor light emitting device having a novel structure of FIG.
It is also to be understood that when an element such as a layer, region or substrate is referred to as being present on another element "on," it is understood that it may be directly on the other element or there may be an intermediate element in between There will be.
The display device described in this specification includes a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, a slate PC, , A Tablet PC, an Ultra Book, 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 embodiments described herein may be applied to a device capable of being displayed, even in the form of a new product to be developed in the future.
According to the illustrated example, the information processed in the control unit of the display device 100 may be displayed using a flexible display.
The flexible display includes a display that can be bent, twistable, collapsible, and curlable, which can be bent by an external force. For example, a flexible display can be a display made on a thin, flexible substrate that can be bent, bent, folded or rolled like paper while maintaining the display characteristics of conventional flat panel displays.
In a state where the flexible display is not bent (for example, a state having an infinite radius of curvature, hereinafter referred to as a first state), the display area of the flexible display is flat. In the first state, the display area may be a curved surface in a state of being bent by an external force (for example, a state having a finite radius of curvature, hereinafter referred to as a second state). As shown in the figure, the information displayed in the second state may be time information output on the curved surface. Such visual information is realized by independently controlling the emission of a sub-pixel arranged in a matrix form. The unit pixel means a minimum unit for implementing one color.
The unit pixel of the flexible display may be implemented by a semiconductor light emitting device. In the present invention, a light emitting diode (LED) is exemplified as one type of semiconductor light emitting device for converting a current into light. The light emitting diode is formed in a small size, so that it can serve as a unit pixel even in the second state.
Hereinafter, a flexible display implemented using the light emitting diode will be described in detail with reference to the drawings.
FIG. 2 is a partial enlarged view of a portion A of FIG. 1, FIGS. 3 A and 3B are cross-sectional views taken along lines BB and CC of FIG. 2, FIG. 4 is a conceptual view of a flip chip type semiconductor light emitting device of FIG. FIGS. 5A to 5C are conceptual diagrams showing various forms of implementing a color in relation to a flip chip type semiconductor light emitting device.
Referring to FIGS. 2, 3A and 3B, a display device 100 using a passive matrix (PM) semiconductor light emitting device as a display device 100 using a semiconductor light emitting device is illustrated. However, the example described below is also applicable to an active matrix (AM) semiconductor light emitting device.
The display device 100 includes a 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 substrate 110 may be a flexible substrate. For example, to implement a flexible display device, the substrate 110 may comprise glass or polyimide (PI). In addition, any insulating material such as PEN (polyethylene naphthalate) and PET (polyethylene terephthalate) may be used as long as it is insulating and flexible. In addition, the substrate 110 may be either a transparent material or an opaque material.
The substrate 110 may be a wiring substrate on which the first electrode 120 is disposed, so that the first electrode 120 may be positioned on the substrate 110.
The insulating layer 160 may be disposed on the substrate 110 on which the first electrode 120 is located and the auxiliary electrode 170 may be disposed on the insulating layer 160. In this case, a state in which the insulating layer 160 is laminated on the substrate 110 may be one wiring substrate. More specifically, the insulating layer 160 is formed of a flexible material such as polyimide (PI), polyimide (PET), or PEN, and is integrally formed with the substrate 110 to form 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 and corresponds to the position of the first electrode 120. For example, the auxiliary electrode 170 may be in the form of a dot and may be electrically connected to the first electrode 120 by an electrode hole 171 passing through the insulating layer 160. The electrode hole 171 may be formed by filling a via hole with a conductive material.
Referring to these drawings, the conductive adhesive layer 130 is formed on one surface of the insulating layer 160, but the present invention is not limited thereto. For example, a layer having a specific function may be formed between the insulating layer 160 and the conductive adhesive layer 130, or a structure in which the conductive adhesive layer 130 is disposed on the substrate 110 without the insulating layer 160 It is also possible. In the structure in which the conductive adhesive layer 130 is disposed on the substrate 110, the conductive adhesive layer 130 may serve as an insulating layer.
The conductive adhesive layer 130 may be a layer having adhesiveness and conductivity. To this end, the conductive adhesive layer 130 may be mixed with a substance having conductivity and a substance having adhesiveness. Also, the conductive adhesive layer 130 has ductility, thereby enabling the flexible function in the display device.
As an example, the conductive adhesive layer 130 may be an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing conductive particles, or the like. The conductive adhesive layer 130 may be formed as a layer having electrical insulation in the horizontal X-Y direction while permitting electrical interconnection in the Z direction passing through the thickness. 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 part of the anisotropic conductive film has conductivity due to the anisotropic conductive medium. Hereinafter, the anisotropic conductive film is described as being subjected to heat and pressure, but other methods may be used to partially conduct the anisotropic conductive film. In this method, for example, either the heat or the pressure may be applied, or UV curing may be performed.
In addition, the anisotropic conduction medium can be, for example, a conductive ball or a conductive particle. According to the example, in the present example, 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 specific portions are conductive by the conductive balls. The anisotropic conductive film may be a state in which a plurality of particles coated with an insulating film made of a polymer material are contained in the core of the conductive material. In this case, the insulating film is broken by heat and pressure, . At this time, the shape of the core may be deformed to form a layer in contact with each other in the thickness direction of the film. As a more specific example, heat and pressure are applied to the anisotropic conductive film as a whole, and the electrical connection in the Z-axis direction is partially formed by the height difference of the mating member adhered by the anisotropic conductive film.
As another example, the anisotropic conductive film may be in a state in which a plurality of particles coated with a conductive material are contained in the insulating core. In this case, the conductive material is deformed (pressed) to the portion where the heat and the pressure are applied, so that the conductive material becomes conductive in the thickness direction of the film. As another example, it is possible that the conductive material penetrates the insulating base member in the Z-axis direction and has conductivity in the thickness direction of the film. In this case, the conductive material may have a pointed end.
According to the present invention, the anisotropic conductive film may be a fixed array anisotropic conductive film (ACF) in which conductive balls are inserted into one surface of an insulating base member. More specifically, the insulating base member is formed of a material having adhesiveness, and the conductive ball is concentrated on the bottom portion of the insulating base member, and is deformed together with the conductive ball when heat and pressure are applied to the base member So that they have conductivity in the vertical direction.
However, the present invention is not limited thereto. The anisotropic conductive film may be formed by randomly mixing conductive balls into an insulating base member or by forming a plurality of layers in which a conductive ball is placed in a double- ACF) are all available.
The anisotropic conductive paste is a combination of a paste and a conductive ball, and may be a paste in which a conductive ball is mixed with an insulating and adhesive base material. In addition, solutions containing conductive particles can be solutions in the form of conductive particles or nanoparticles.
Referring again to FIG. 5, the second electrode 140 is located in the insulating layer 160, away from the auxiliary electrode 170. That is, the conductive adhesive layer 130 is disposed on the insulating layer 160 on which the auxiliary electrode 170 and the second electrode 140 are disposed.
After the conductive adhesive layer 130 is formed in a state where the auxiliary electrode 170 and the second electrode 140 are positioned in the insulating layer 160, the semiconductor light emitting device 150 is connected to 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 the 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 semiconductor layer 155 in which a p-type electrode 156, a p-type electrode 156 are formed, an active layer 154 formed on the p-type semiconductor layer 155, And an n-type electrode 152 disposed on the n-type semiconductor layer 153 and the p-type electrode 156 on the n-type semiconductor layer 153 and 154 in the horizontal direction. In this case, 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 again to FIGS. 2, 3A and 3B, the auxiliary electrode 170 is elongated in one direction, and one auxiliary electrode may be electrically connected to the plurality of semiconductor light emitting devices 150. For example, the p-type electrodes of the right and left semiconductor light emitting elements may be electrically connected to one auxiliary electrode around the auxiliary electrode.
More specifically, the semiconductor light emitting device 150 is inserted into the conductive adhesive layer 130 by heat and pressure, and the semiconductor light emitting device 150 is inserted into the conductive adhesive layer 130 through the p- And only the portion between the n-type electrode 152 and the second electrode 140 of the semiconductor light emitting device 150 has conductivity and the semiconductor light emitting device does not have a conductive property because the semiconductor light emitting device is not press- The conductive adhesive layer 130 not only couples the semiconductor light emitting device 150 and the auxiliary electrode 170 and the semiconductor light emitting device 150 and the second electrode 140 but also forms an electrical connection.
In addition, the plurality of semiconductor light emitting devices 150 constitute a light emitting element array, and the phosphor layer 180 is formed in the light emitting element array.
The light emitting element array may include a plurality of semiconductor light emitting elements having different brightness values. Each of the semiconductor light emitting devices 150 constitutes a unit pixel and is electrically connected to the first electrode 120. For example, the first electrodes 120 may be a plurality of semiconductor light emitting devices, and the semiconductor light emitting devices may be electrically connected to any one of the plurality of first electrodes.
Also, since the semiconductor light emitting devices are connected in a flip chip form, the semiconductor light emitting devices grown on the transparent dielectric substrate can be used. The semiconductor light emitting devices may be, for example, a nitride semiconductor light emitting device. Since the semiconductor light emitting device 150 has excellent brightness, individual unit pixels can be formed with a small size.
According to the structure, the barrier ribs 190 may be formed between the semiconductor light emitting devices 150. In this case, the barrier ribs 190 may separate the individual unit pixels from each other, and may be integrally formed with the conductive adhesive layer 130. For example, by inserting the semiconductor light emitting device 150 into the anisotropic conductive film, the base member of the anisotropic conductive film can form the partition.
Also, if the base member of the anisotropic conductive film is black, the barrier 190 may have a reflection characteristic and a contrast may be increased without a separate black insulator.
As another example, the barrier ribs 190 may be provided separately from the reflective barrier ribs. In this case, the barrier rib 190 may include a black or white insulation depending on the purpose of the display device. When a barrier of a white insulator is used, an effect of enhancing reflectivity may be obtained. When a barrier of a black insulator is used, a contrast characteristic may be increased while having a reflection characteristic.
The phosphor layer 180 may be located on the 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 converts the blue (B) light into the color of a unit pixel. The phosphor layer 180 may be a red phosphor 181 or a green phosphor 182 constituting an individual pixel.
That is, a red phosphor 181 capable of converting blue light into red (R) light can be laminated on the blue semiconductor light emitting element 151 at a position forming a red unit pixel, A green phosphor 182 capable of converting blue light into green (G) light may be laminated on the blue semiconductor light emitting element 151. [ In addition, only the blue semiconductor light emitting element 151 can be used alone in a portion constituting a blue unit pixel. In this case, the unit pixels of red (R), green (G), and blue (B) can form one pixel. More specifically, phosphors of one color may be stacked along each line of the first electrode 120. Accordingly, one line in the first electrode 120 may be an electrode for controlling one color. In other words, red (R), green (G), and blue (B) may be arranged in order along the second electrode 140, thereby realizing a unit pixel.
(R), green (G), and blue (B) unit pixels may be implemented by combining the semiconductor light emitting device 150 and the quantum dot QD instead of the fluorescent material. have.
In addition, a black matrix 191 may be disposed between each of the phosphor layers to improve contrast. That is, the black matrix 191 can improve the contrast of light and dark.
However, the present invention is not limited thereto, and other structures for implementing blue, red, and green may be applied.
5A, each of the semiconductor light emitting devices 150 includes gallium nitride (GaN), indium (In) and / or aluminum (Al) are added together to form a high output light Device.
In this case, the semiconductor light emitting device 150 may be a red, green, and blue semiconductor light emitting device to form a unit pixel (sub-pixel), respectively. For example, red, green, and blue semiconductor light emitting elements R, G, and B are alternately arranged, and red, green, and blue unit pixels Form a single pixel, through which a full color display can be implemented.
Referring to FIG. 5B, the semiconductor light emitting device may include a white light emitting device W having a yellow phosphor layer for each individual 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 element W to form a unit pixel. Further, a unit pixel can be formed by using a color filter in which red, green, and blue are repeated on the white light emitting element W.
Referring to FIG. 5C, a red phosphor layer 181, a green phosphor layer 182, and a blue phosphor layer 183 may be provided on the ultraviolet light emitting element UV. As described above, the semiconductor light emitting device can be used not only for visible light but also for ultraviolet (UV), and can be extended to a form of a semiconductor light emitting device in which ultraviolet (UV) can be used as an excitation source of the upper phosphor .
The semiconductor light emitting device 150 is disposed on the conductive adhesive layer 130 and constitutes a unit pixel in the display device. Since the semiconductor light emitting device 150 has excellent brightness, individual unit pixels can be formed with a small size. The size of the individual semiconductor light emitting device 150 may be 80 mu m or less on one side and may be a rectangular or square device. In the case of a rectangle, the size may be 20 X 80 μm or less.
Also, even if a square semiconductor light emitting device 150 having a length of 10 m on one side is used as a unit pixel, sufficient brightness for forming a display device appears. Accordingly, when the unit pixel is a rectangular pixel having a side of 600 mu m and the other side of 300 mu m as an example, the distance of the semiconductor light emitting element becomes relatively large. Accordingly, in such a case, it becomes possible to implement a flexible display device having HD picture quality.
The display device using the semiconductor light emitting device described above can be manufactured by a novel manufacturing method. Hereinafter, the manufacturing method will be described with reference to FIG.
The conductive adhesive layer 130 is formed on the insulating layer 160 on which the auxiliary electrode 170 and the second electrode 140 are disposed. A first electrode 120, an auxiliary electrode 170, and a second electrode 140 are formed on the wiring substrate, and the insulating layer 160 is formed on the first substrate 110 to form a single substrate (or a wiring substrate) . In this case, the first electrode 120 and the second electrode 140 may be arranged in mutually orthogonal directions. In addition, the first substrate 110 and the insulating layer 160 may include glass or polyimide (PI), respectively, in order to implement a flexible display device.
The conductive adhesive layer 130 may be formed, for example, by an anisotropic conductive film, and an anisotropic conductive film may be applied to the substrate on which the insulating layer 160 is disposed.
A second substrate 112 corresponding to the positions of the auxiliary electrode 170 and the second electrodes 140 and having a plurality of semiconductor light emitting elements 150 constituting individual pixels is disposed on the semiconductor light emitting element 150 Are arranged so as to face the auxiliary electrode 170 and the second electrode 140.
In this case, the second substrate 112 is a growth substrate for growing the semiconductor light emitting device 150, and may be a spire substrate or a silicon substrate.
When the semiconductor light emitting device is formed in units of wafers, the semiconductor light emitting device can be effectively used in a display device by having an interval and a size at which a display device can be formed.
Then, the wiring substrate and the second substrate 112 are thermally bonded. For example, the wiring board and the second substrate 112 may be thermocompression-bonded using an ACF press head. The wiring substrate and the second substrate 112 are bonded by the thermocompression bonding. Only the portion between the semiconductor light emitting device 150 and the auxiliary electrode 170 and the second electrode 140 has conductivity due to the characteristics of the anisotropic conductive film having conductivity by thermocompression, The device 150 may be electrically connected. At this time, the semiconductor light emitting device 150 is inserted into the anisotropic conductive film, and partition walls may be formed between the semiconductor light emitting devices 150.
Then, the second substrate 112 is removed. For example, the second substrate 112 may be removed using a laser lift-off method (LLO) or a chemical lift-off method (CLO).
Finally, the second substrate 112 is removed to expose the semiconductor light emitting devices 150 to the outside. If necessary, a transparent insulating layer (not shown) may be formed by coating a wiring substrate on which the semiconductor light emitting device 150 is coupled with silicon oxide (SiOx) or the like.
Further, the method may further include forming a phosphor layer on one 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 a red phosphor or a green phosphor for converting the blue (B) A layer can be formed on one surface of the device.
The manufacturing method and structure of the display device using the semiconductor light emitting device described above can be modified into various forms. For example, a vertical semiconductor light emitting device may be applied to the display device described above. Hereinafter, the vertical structure will be described with reference to Figs. 5 and 6. Fig.
In the modifications or embodiments described below, the same or similar reference numerals are given to the same or similar components as those of the previous example, and the description is replaced with the first explanation.
8 is a cross-sectional view taken along the line DD of FIG. 7, and FIG. 9 is a conceptual view illustrating a vertical semiconductor light emitting device of FIG. 8. FIG. 7 is a perspective view showing another embodiment of a display device using the semiconductor light emitting device of the present invention, to be.
Referring to these drawings, the display device may be a display device using a passive matrix (PM) vertical semiconductor light emitting device.
The display device includes 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 is a wiring substrate on which the first electrode 220 is disposed. The substrate 210 may include polyimide (PI) to implement a flexible display device. In addition, any insulating and flexible material may be used.
The first electrode 220 is disposed on the substrate 210 and may be formed as a long bar electrode in one direction. The first electrode 220 may serve as a data electrode.
A conductive adhesive layer 230 is formed on the substrate 210 on which the first electrode 220 is located. The conductive adhesive layer 230 may be formed of an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing a conductive particle, or the like, as in a display device using a flip chip type light emitting device. ) And the like. However, the present embodiment also exemplifies the case where the conductive adhesive layer 230 is realized by the anisotropic conductive film.
If the semiconductor light emitting device 250 is connected to the semiconductor light emitting device 250 by applying heat and pressure after the anisotropic conductive film is positioned in a state where the first electrode 220 is positioned on the substrate 210, And is electrically connected to the electrode 220. In this case, the semiconductor light emitting device 250 may be disposed on the first electrode 220.
As described above, the electrical connection is generated because heat and pressure are applied to the anisotropic conductive film to partially conduct in the thickness direction. Therefore, in the anisotropic conductive film, it is divided into a portion 231 having conductivity in the thickness direction and a portion 232 having no conductivity.
In addition, since the anisotropic conductive film contains an adhesive component, the conductive adhesive layer 230 realizes electrical connection as well as mechanical bonding between the semiconductor light emitting element 250 and the first electrode 220.
Thus, the semiconductor light emitting device 250 is positioned on the conductive adhesive layer 230, thereby forming individual pixels in the display device. Since the semiconductor light emitting device 250 has excellent brightness, individual unit pixels can be formed with a small size. The size of the individual semiconductor light emitting device 250 may be 80 μm or less on one side and may be a rectangular or square device. In the case of a rectangle, the size may be 20 X 80 μm or less.
The semiconductor light emitting device 250 may have a vertical structure.
A plurality of second electrodes 240 electrically connected to the vertical semiconductor light emitting device 250 are disposed between the vertical semiconductor light emitting devices in a direction crossing the longitudinal direction of the first electrode 220.
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. In this case, 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 As shown in FIG. Since the vertical semiconductor light emitting device 250 can arrange the electrodes up and down, it has a great advantage that the chip size can be reduced.
Referring to FIG. 8 again, a phosphor layer 280 may be formed on one side 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 a phosphor layer 280 for converting the blue (B) . In this case, the phosphor layer 280 may be a red phosphor 281 and a green phosphor 282 constituting individual pixels.
That is, a red phosphor 281 capable of converting blue light into red (R) light can be laminated on the blue semiconductor light emitting element 251 at a position forming a red unit pixel, A green phosphor 282 capable of converting blue light into green (G) light may be laminated on the blue semiconductor light emitting element 251. In addition, only the blue semiconductor light emitting element 251 can be used alone in a portion constituting a blue unit pixel. In this case, the unit pixels of red (R), green (G), and blue (B) can form one pixel.
However, the present invention is not limited thereto, and other structures for implementing blue, red, and green may be applied to a display device to which a flip chip type light emitting device is applied, as described above.
The second electrode 240 is located between the semiconductor light emitting devices 250 and 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 columns of the semiconductor light emitting devices 250.
The second electrode 240 may be positioned between the semiconductor light emitting devices 250 because the distance between the semiconductor light emitting devices 250 forming the individual pixels is sufficiently large.
The second electrode 240 may be formed as a long bar-shaped electrode in one direction and may be disposed in a direction perpendicular to the first electrode.
The second electrode 240 and the semiconductor light emitting device 250 may be electrically connected by a connection electrode protruding from the second electrode 240. More specifically, the connection 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 a part of the ohmic electrode by printing or vapor deposition. Accordingly, the second electrode 240 and the n-type electrode of the semiconductor light emitting device 250 can be electrically connected.
According to the example, the second electrode 240 may be disposed on the conductive adhesive layer 230. A transparent insulating layer (not shown) containing silicon oxide (SiOx) or the like may be formed on the substrate 210 on which the semiconductor light emitting device 250 is formed. When the second electrode 240 is positioned after the transparent insulating layer is formed, the second electrode 240 is positioned on the transparent insulating layer. In addition, the second electrode 240 may be formed spaced apart from the conductive adhesive layer 230 or the transparent insulating layer.
If a transparent electrode such as ITO (Indium Tin Oxide) is used for positioning the second electrode 240 on the semiconductor light emitting device 250, the problem that the ITO material has poor adhesion with the n-type semiconductor layer have. Accordingly, the present invention has an advantage in that the second electrode 240 is positioned between the semiconductor light emitting devices 250, so that a transparent electrode such as ITO is not used. Therefore, the light extraction efficiency can be improved by using a conductive material having good adhesiveness with the n-type semiconductor layer as a horizontal electrode without being bound by transparent material selection.
According to the structure, the barrier ribs 290 may be positioned between the semiconductor light emitting devices 250. That is, the barrier ribs 290 may be disposed between the vertical semiconductor light emitting devices 250 to isolate the semiconductor light emitting devices 250 forming the individual pixels. In this case, the barrier ribs 290 may separate the individual unit pixels from each other, and may be formed integrally with the conductive adhesive layer 230. For example, by inserting the semiconductor light emitting device 250 into the anisotropic conductive film, the base member of the anisotropic conductive film can form the partition.
Also, if the base member of the anisotropic conductive film is black, the barrier ribs 290 may have a reflection characteristic and a contrast may be increased without a separate black insulator.
As another example, as the partition 190, a reflective barrier may be separately provided. The barrier ribs 290 may include black or white insulators depending on the purpose of the display device.
If the second electrode 240 is directly disposed on the conductive adhesive layer 230 between the semiconductor light emitting devices 250, the barrier ribs 290 may be formed between the vertical semiconductor light emitting device 250 and the second electrode 240 As shown in FIG. Therefore, individual unit pixels can be formed with a small size by using the semiconductor light emitting device 250, and the distance between the semiconductor light emitting device 250 can be relatively large enough so that the second electrode 240 can be electrically connected to the semiconductor light emitting device 250 ), And it is possible to realize a flexible display device having HD picture quality.
In addition, according to the present invention, a black matrix 291 may be disposed between the respective phosphors to improve the contrast. That is, this black matrix 291 can improve the contrast of light and dark.
As described above, the semiconductor light emitting device 250 is disposed on the conductive adhesive layer 230, thereby forming individual pixels in the display device. Since the semiconductor light emitting device 250 has excellent brightness, individual unit pixels can be formed with a small size. Therefore, a full color display in which red (R), green (G), and blue (B) unit pixels form one pixel can be realized by the semiconductor light emitting device.
In the display device of the present invention described above, the size of the semiconductor light emitting device is small, and it is difficult to increase the brightness of the display device. This is because the area of the upper surface (light emitting surface) where light is emitted from the semiconductor light emitting device is small, and therefore there is a limit to increase in luminance. In addition, in the semiconductor light emitting device having a vertical structure, a part of the light emitting surface is shrunk by the wiring electrode contacting the area of the light emitting surface. In this case, the upper wiring electrode structure is determined in consideration of operating voltage, light extraction efficiency, and light spreading. In the semiconductor light emitting device of several tens of microunits, a simple structure of a rectangular parallelepiped shape is obtained due to a process margin do. In such a structure, if the area of the upper wiring electrode (or the contact area between the wiring electrode and the semiconductor light emitting element) is reduced, there is a problem that the operating voltage increases.
The present invention provides a semiconductor light emitting device having a novel structure capable of solving such a problem. Hereinafter, a display device to which a semiconductor light emitting device having a novel structure is applied and a method of manufacturing the same will be described.
Fig. 10 is an enlarged view of a portion A in Fig. 1 for explaining another embodiment of the present invention to which a semiconductor light emitting device having a new structure is applied, Fig. 11 is a cross- 10, and FIG. 13 is a conceptual diagram showing a semiconductor light emitting device having a novel structure of FIG. 15 is a photograph of a product of the semiconductor light emitting device of FIG. 13, and FIG. 15B is a view showing a well structure and a wiring electrode of the present invention. FIG. 14 is a current flow chart comparing the display device of FIG. 10 with a conventional display device, FIG.
10, 11, and 12, a display device 1000 using a passive matrix (PM) vertical semiconductor light emitting device as a display device 1000 using a semiconductor light emitting device is illustrated. However, the example described below is also applicable to an active matrix (AM) semiconductor light emitting device.
The display device 1000 includes a substrate 1010, a first electrode 1020, a conductive adhesive layer 1030, a second electrode 1040, and a plurality of semiconductor light emitting devices 1050. Here, the first electrode 1020 and the second electrode 1040 may each include a plurality of electrode lines.
The substrate 1010 is a wiring substrate on which the first electrode 1020 is disposed, and may include polyimide (PI) to implement a flexible display device. In addition, any insulating and flexible material may be used.
The first electrode 1020 is disposed on the substrate 1010 and may be formed as a long bar electrode in one direction. The first electrode 1020 may serve as a data electrode.
A conductive adhesive layer 1030 is formed on the substrate 1010 where the first electrode 1020 is located. The conductive adhesive layer 1030 may be an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing a conductive particle, or the like, as in a display device using a flip chip type light emitting device described above. solution or the like. However, in this embodiment, the conductive adhesive layer 1030 may be replaced with an adhesive layer. For example, if the first electrode 1020 is not located on the substrate 1010 but is formed integrally with the conductive electrode of the semiconductor light emitting device, the adhesive layer may not be conductive.
A plurality of second electrodes 1040 electrically connected to the semiconductor light emitting device 1050 are disposed between the semiconductor light emitting devices in a direction crossing the longitudinal direction of the first electrode 1020.
According to the illustration, the second electrode 1040 may be positioned on the conductive adhesive layer 1030. That is, the conductive adhesive layer 1030 is disposed between the wiring substrate and the second electrode 1040. The second electrode 1040 may be electrically connected to the semiconductor light emitting device 1050 by contact with the semiconductor light emitting device 1050.
The plurality of semiconductor light emitting devices 1050 are coupled to the conductive adhesive layer 1030 and are electrically connected to the first electrode 1020 and the second electrode 1040. [
A transparent insulating layer (not shown) containing silicon oxide (SiOx) or the like may be formed on the substrate 1010 on which the semiconductor light emitting element 1050 is formed. When the second electrode 1040 is positioned after the transparent insulation layer is formed, the second electrode 1040 is positioned on the transparent insulation layer. In addition, the second electrode 1040 may be formed apart from the conductive adhesive layer 1030 or the transparent insulating layer.
As shown in the figure, the plurality of semiconductor light emitting devices 1050 can form a plurality of rows in a direction parallel to a plurality of electrode lines provided in the first electrode 1020. However, the present invention is not limited thereto. For example, the plurality of semiconductor light emitting devices 1050 may form a plurality of rows along the second electrode 1040.
Furthermore, the display device 1000 may further include a phosphor layer 1080 formed on one surface of the plurality of semiconductor light emitting devices 1050. For example, the semiconductor light emitting device 1050 is a blue semiconductor light emitting device that emits blue (B) light, and the phosphor layer 1080 converts the blue (B) light into the color of a unit pixel. The phosphor layer 1080 may be a red phosphor 1081 or a green phosphor 1082 constituting an individual pixel. That is, a red phosphor 1081 capable of converting blue light into red (R) light can be laminated on the blue semiconductor light emitting element 1051a at a position forming a red unit pixel, A green phosphor 1082 capable of converting blue light into green (G) light can be laminated on the blue semiconductor light emitting element 1051b. Further, only the blue semiconductor light emitting element 1051c can be used solely in the portion constituting the blue unit pixel. In this case, the unit pixels of red (R), green (G), and blue (B) can form one pixel. More specifically, phosphors of one color may be laminated along the respective lines of the first electrode 1020. Accordingly, one line in the first electrode 1020 may be an electrode for controlling one color. That is, red (R), green (G), and blue (B) may be arranged in order along the second electrode 1040, and a unit pixel may be realized through the red However, the present invention is not necessarily limited thereto. Instead of the fluorescent material, the semiconductor light emitting device 1050 and the quantum dot QD may be combined to form a unit pixel emitting red (R), green (G) and blue (B) Can be implemented.
In order to improve the contrast of the phosphor layer 1080, the display device may further include a black matrix 1091 disposed between the phosphors. The black matrix 1091 may be formed in such a manner that a gap is formed between the phosphor dots and a black material fills the gap. Through this, the black matrix 1091 absorbs the external light reflection and can improve contrast of light and dark. The black matrix 1091 is located between the respective phosphor layers along the first electrode 1020 in the direction in which the phosphor layers 1080 are stacked. In this case, a phosphor layer is not formed at a position corresponding to the blue semiconductor light emitting element 1051, but a black matrix 1091 is provided between the blue light emitting element 1051c and the blue light emitting element 1051c Respectively, on both sides. The black matrix 1091 serves as a barrier to prevent color mixing among the phosphors.
In the semiconductor light emitting device 1050 of this example, since the semiconductor light emitting device 1050 can arrange the electrodes up and down in this example, it has a great advantage that the chip size can be reduced. However, since the electrodes are arranged at the upper and lower sides, the light emitting surface is covered by the electrodes, and the area of the light emitting surface is reduced. More specifically, the display device has a front surface on which the visual information is output, and a portion where the second electrode 1040 and the semiconductor light emitting device 1050 are electrically connected is electrically connected to the light output by the semiconductor light emitting device toward the front surface .
Therefore, the semiconductor light emitting device of the present embodiment has a mechanism that maximizes the contact surface where the electrode is in electrical contact with the semiconductor light emitting device, while minimizing a portion where the light emitting surface is shielded by the electrode. Hereinafter, Will be described in more detail.
13, for example, the semiconductor light emitting device 1050 includes a first conductive type electrode 1156, a first conductive type semiconductor layer 1155 on which a first conductive type electrode 1156 is formed, An active layer 1154 formed on the first conductivity type semiconductor layer 1155 and a second conductivity type semiconductor layer 1153 formed on the active layer 1154. [
According to the structure, the second electrode 1040 is connected to the second conductivity type semiconductor layer. In this example, the case where the second conductive electrode is not separately provided for each semiconductor light emitting element, and the second conductive electrode is formed integrally with the second electrode 1040 will be described. In this case, the second electrode may be formed without depositing the second conductive electrode on each semiconductor light emitting device.
The first conductivity type semiconductor layer 1155 and the second conductivity type semiconductor layer 1153 overlap each other in the vertical direction (or thickness direction of the semiconductor light emitting device or the display device), and the second conductivity type semiconductor layer 1153, And the first conductive type electrode 1156 is disposed on the lower surface of the first conductive type semiconductor layer 1155. The first conductive type semiconductor layer 1155 is formed on the lower surface of the first conductive type semiconductor layer 1155, In this case, the upper surface of the second conductivity type semiconductor layer 1153 is one surface of the second conductivity type semiconductor layer 1153 farthest from the first conductivity type semiconductor layer 1155, 1155 may be one surface of the first conductivity type semiconductor layer 1155 farthest from the second conductivity type semiconductor layer 1153. [ The first conductive type electrode 1156 and the second electrode 1040 are disposed on the upper and lower sides of the first conductive type semiconductor layer 1155 and the second conductive type semiconductor layer 1153 .
13, the lower surface of the first conductive type semiconductor layer 1155 may be a surface closest to the wiring substrate, and the upper surface of the second conductive type semiconductor layer may be a wiring It may be the farthest surface to the substrate.
More specifically, the first conductive type electrode 1156 and the first conductive type semiconductor layer 1155 may be a p-type electrode and a p-type semiconductor layer, respectively, and the second electrode 1040 and the second conductive type The semiconductor layer 1153 may be an n-type electrode and an n-type semiconductor layer, respectively. More specifically, the first conductivity type semiconductor layer 1155 may be a P-type GaN layer and the second conductivity type semiconductor layer 1153 may be an N-type Gan layer.
In this case, the p-type electrode located at the upper portion may be electrically connected to the first electrode 1020 by the conductive adhesive layer 1030, and the n-type electrode located at the lower portion may serve as the second electrode 1040, They can be connected to each other. However, the present invention is not limited thereto, and the first conductivity type may be n-type and the second conductivity type may be p-type.
At this time, the semiconductor light emitting device may include a passivation layer 1157 formed to surround the first conductivity type semiconductor layer 1155 and the side surfaces of the second conductivity type semiconductor layer 1153. The passivation layer 1157 is formed of an insulating material to cover the side surface of the semiconductor light emitting device to stabilize the characteristics of the semiconductor light emitting device. Since the gap between the first conductivity type semiconductor layer 1155 and the second conductivity type semiconductor layer 1153 is electrically disconnected by the passivation layer 1157, the P type GaN and the N type GaN can be insulated from each other.
The active layer 1154 is disposed between the first conductivity type semiconductor layer 1155 and the second conductivity type semiconductor layer 1153 and is electrically connected to the first conductivity type electrode 1156 and the second electrode 1040 The light is emitted by the current flowing between the light emitting elements.
In this example, at least one of the semiconductor light emitting devices may have a recessed groove 1160 formed in at least a part of the second conductive type semiconductor layer 1153. [ At least a part of the wiring electrodes for supplying an electric signal to the semiconductor light emitting elements may be disposed in the recess groove 1160.
For example, as shown in FIG. 13, the second electrode 1040 may be disposed in the recess groove 1160 as the wiring electrode. That is, the second electrode 1040 is formed on the second conductive type semiconductor layer 1153 and extends laterally to electrically connect the adjacent semiconductor light emitting elements, and the second electrode is formed on the recessed groove 1160, . However, the present invention is not limited thereto, and the second conductive type electrode may be separately provided in each semiconductor light emitting element. In this case, the second conductive type electrode 1152 is disposed in the recessed groove 1160 as at least a part of the wiring electrode, and the details will be described later.
Referring to FIGS. 13 and 15B, for example, the recess groove 1160 may have a bottom portion 1161 and a side wall portion 1162. The side wall portion 1162 may be formed along the edge of the second conductive type semiconductor layer 1153 to surround the bottom portion 1161. In this case, the recessed recess is recessed from the one surface of the second conductive type semiconductor layer 1153 toward the other surface, and the portion except for the recessed groove 1160 on the one surface may be formed into a rectangular annular shape.
The bottom portion 1161 is formed in the region of the second conductive type semiconductor layer 1153 and overlaps with the active layer 1154. [ The bottom portion 1161 is disposed parallel to one surface of the second conductive type semiconductor layer 1153 and the side wall portion 1162 completely surrounds the bottom portion 1161 and corresponds to the rectangular annular shape As shown in FIG.
According to the illustrated example, the wiring electrode may be formed to cover at least a part of the sidewall portion 1162. More specifically, the second electrode 1040 is formed so as to cover at least a part of the side wall portion 1162. In this case, the second electrode 1040 may be disposed on either side of the sidewall 1162. For example, the side wall portion 1162 may include a pair of side walls 1162a and 1162b parallel to each other, the second electrode 1040 may cover any one of the pair of side walls, Is not covered.
In addition, the side wall portion may include another pair of side walls 1162c and 1162d disposed perpendicularly to the pair of side walls, and the second electrode 1040 may be formed to cover a portion of the other pair of side walls . At this time, the other pair of sidewalls has a first sidewall 1162c and a second sidewall 1162d, and the second electrode 1040 includes the first sidewall 1162c, the bottom 1161, And a line passing through the second side wall 1162d in order can be formed. According to the well structure in which the recessed trench 1160 is formed in the second conductivity type semiconductor layer 1153 as described above, at least the portion of the second electrode 1040 coated with the second electrode 1040 And the second conductive type semiconductor layer 1153 are widened.
15B, the height of the sidewall portion 1162 may be 10 to 20% of the length of any one of the pair of sidewalls, or a portion where the first sidewall 1162c overlaps with the wiring electrode To 25% of the length of the &lt; / RTI &gt; For example, when the size of the second conductivity type semiconductor layer is 20 占 퐉 x 49 占 퐉 and the bottom portion 1161 has a recessed groove of 14 占 퐉 34 占 퐉, the second electrode 1040 is 10 占 퐉 in the longitudinal direction, The contact area between the second electrode 1040 and the second conductivity type semiconductor layer 1153 is increased by about 1.25 times when the second conductivity type semiconductor layer is covered.
The side wall portion 1162 is inclined with respect to a direction perpendicular to the bottom portion 1161. As shown in FIG. For example, the recessed groove may be formed to have an increased cross-sectional area as the distance from the first conductive type semiconductor layer 1155 increases due to the inclination of the side wall portion 1162. The actual area of the side wall portion 1162 may increase and the contact area between the second electrode 1040 and the second conductive type semiconductor layer 1153 may be larger than the above- Can be increased.
FIG. 14 is an I-V graph comparing the present invention with an existing display device. It can be seen that a difference in operating voltage appears when the same current is supplied. For example, it can be seen that the operating voltage is reduced by 0.5 to 1 V at a current of 100 mA. As described above, according to the semiconductor light emitting device having the well structure like the present invention, the operation voltage can be lowered and the light extraction efficiency can be improved at the same time.
15A and 15B, irregularities may be formed on the surface of the bottom portion 1161. FIG. The irregularities may be formed in the size of micrometers, and may be formed at the time of etching the recessed recesses 1160 due to the residue after the growth substrate and the second conductive type semiconductor layer 1153 are separated.
The irregularities may be formed on at least a part of the side wall part 1162 and the irregularities of the side wall part 1162 may be formed to be smaller than the irregularities of the bottom part 1161. This is because a lot of irregularities corresponding to the shape of the residue can be formed on the bottom due to the influence of the residue. The contact area between the second electrode 1040 and the second conductive type semiconductor layer 1153 is further increased by the unevenness and the light emitting surface of the semiconductor light emitting device can also be increased.
According to the structure of the new display device as described above, not only a structure for improving the brightness while reducing the operating voltage, but also a manufacturing process capable of ensuring reliability in the process margin of the semiconductor light emitting device can be realized.
Hereinafter, a manufacturing method for forming the structure of the new display device as described above will be described in more detail with reference to the accompanying drawings. 16A, 16B, 16C, 16D, 17A, 17B, 17, and 17D are cross-sectional views illustrating a method of manufacturing a display device using the semiconductor light emitting device of the present invention.
First, according to the manufacturing method, the second conductive type semiconductor layer 1153, the active layer 1154, and the first conductive type semiconductor layer 1155 are grown on the growth substrate W or the semiconductor wafer, respectively (Fig. 16A).
When the second conductive type semiconductor layer 1153 is grown, an active layer 1154 is grown on the first conductive type semiconductor layer 1152 and then a first conductive type semiconductor layer 1154 is formed on the active layer 1154. Next, Layer 1155 is grown. When the second conductivity type semiconductor layer 1153, the active layer 1154 and the first conductivity type semiconductor layer 1155 are sequentially grown as described above, the second conductivity type semiconductor layer 1153, the active layer 1154, 1154 and the first conductive type semiconductor layer 1155 form a laminated structure.
The growth substrate W may be formed of any material having optical transparency, for example, sapphire (Al 2 O 3), GaN, ZnO, or AlO, but is not limited thereto. Further, the growth substrate W may be formed of a carrier wafer, which is a material suitable for semiconductor material growth. And may include a conductive substrate or an insulating substrate, for example, a SiC substrate having higher thermal conductivity than a sapphire (Al2O3) substrate, or at least one of Si, GaAs, GaP, InP and Ga2O3 Can be used.
The second conductive type semiconductor layer 1153 may be an n-type semiconductor layer, and may be a nitride semiconductor layer such as n-Gan.
Next, an etching process for separating the p-type semiconductor and the n-type semiconductor and forming a plurality of semiconductor light emitting elements isolated from each other on the substrate is performed. That is, the first conductive type semiconductor layer 1155, the active layer 1154, and the second conductive type semiconductor layer 1153 are etched to isolate the semiconductor light emitting elements on the substrate.
16B, at least a part of the first conductivity type semiconductor layer 1155, the active layer 1154 and the second conductivity type semiconductor layer 1153 are etched to isolate each other on the substrate, Thereby forming a plurality of semiconductor light emitting elements. In this case, the etching may proceed until the substrate is exposed. As another example, the etching may proceed to a state in which a part of the second conductive type semiconductor layer 1153 is left between the semiconductor light emitting elements.
Next, at least one conductive electrode is formed on the semiconductor light emitting devices (FIG. 16C). More specifically, the first conductive type electrode 1156 is formed on one surface of the first conductive type semiconductor layer 1155. That is, after the array of the semiconductor light emitting devices is formed on the substrate, the first conductive type electrode 1156 is stacked on the first conductive type semiconductor layer 1155.
Thereafter, a passivation layer 1157 is formed to surround the side surfaces of the semiconductor light emitting devices (FIG. 16D).
The passivation layer 1157 has a plurality of layers having different refractive indexes so as to reflect light emitted to the side surface, and a material having a relatively high refractive index and a material having a relatively high refractive index can be repeatedly stacked in the plurality of layers .
Thereafter, a step of connecting the first conductive type electrode to the wiring substrate, separating the semiconductor light emitting element from the substrate, and forming a recessed groove in the second conductive type semiconductor layer through etching is performed.
For example, semiconductor light emitting devices are bonded to a wiring substrate using a conductive adhesive layer, and the growth substrate is removed (Fig. 17A). The first electrode 1020 is a lower wiring and is electrically connected to the first conductive electrode 1156 by a conductive ball or the like in the conductive adhesive layer 1030. [ do.
As another example, it is also possible to form a bonding metal on the wiring substrate and selectively bond the semiconductor light emitting element in the growth substrate to the wiring substrate, as shown in Fig. 18 to be described later. In this case, the conductive adhesive layer is not necessary, and the bonding metal is disposed on the first electrode to physically contact the first conductive electrode.
The growth substrate is removed using a laser lift-off method (LLO) or a chemical lift-off method (CLO), whereby the semiconductor light emitting device is separated from the substrate.
Next, a gap formed between the semiconductor light emitting elements is filled with a material that does not flow current (Fig. 17B). As an example, the gap may be filled with polyimide 1158. [ In addition, the polyimide may be filled to completely cover the semiconductor light emitting element. In this case, in the structure without the conductive adhesive layer, the polyimide may be filled between the semiconductor light emitting elements (see FIG. 18).
Thereafter, a pattern is formed on the polyimide (FIG. 17B), and then a recessed groove is formed in the second conductivity type semiconductor layer through etching (FIG. 17C).
The recess groove 1160 may have a bottom portion 1161 and a side wall portion 1162 as described above. The side wall portion 1162 may be formed along the edge of the second conductive type semiconductor layer 1153 to surround the bottom portion 1161. In this case, the recessed recess 1160 is recessed from the one surface of the second conductive type semiconductor layer 1153 toward the other surface, and the portion except for the recessed recess 1160 on the one surface is formed into a rectangular annular shape .
On the other hand, if the growth substrate and the second conductivity type semiconductor layer 1153 are separated from each other, fine irregularities may be generated on the surface of the second conductivity type semiconductor layer 1153. In this case, it is possible to form the concavities and convexities corresponding to the fine irregularities in the recess groove 1160 by performing the etching without chemically treating the fine irregularities.
As another example, an undoped semiconductor layer (not shown) may be formed on one surface of the second conductive type semiconductor layer 1153. In this case, the undoped semiconductor layer may be etched until the second conductive type semiconductor layer 1153 is exposed to the outside. According to this structure, the second conductive type semiconductor layer 1153 forms the bottom of the recessed groove 1160. All or most of the sidewall portion 1162 of the recessed groove 1160 forms the undoped semiconductor layer.
Also, at this time, the growth substrate and the undoped semiconductor layer are separated from each other and then the etching is performed without chemical treatment, so that the recessed groove corresponding to the fine irregularities can be formed in the recessed groove 1160.
More specifically, when a laser beam is emitted using a laser having a wavelength in the ultraviolet region to remove the sapphire substrate, the sapphire and the GaN layer are separated. In the process of separating the growth substrate, a Ga droplet is present between the two interfaces. In order to remove it, the surface may be cleaned using hydrochloric acid or the like, but the undoped current Dry region). In this case, since the dry etching rate or etch rate of the Un-GaN layer is different between the position where the Ga residue remains and the position where the Ga residue remains, the texturing structure can be naturally formed.
17B). Next, a step of electrically connecting the second conductivity type semiconductor layer formed with the recessed groove to the wiring electrode proceeds (FIG. 17D), and then the phosphor layer 1080 is formed to cover the semiconductor light- (Not shown). For example, the second electrode 1040 is directly connected to the second conductive type semiconductor layer 1153 as an upper wiring. More specifically, the second electrode 1040 is deposited or printed on one surface of the second conductive type semiconductor layer 1153 and the recessed recess to form an upper wiring of the semiconductor light emitting device.
At least a part of the wiring electrodes for supplying an electric signal to the semiconductor light emitting devices by the manufacturing process may be disposed in the recessed grooves. According to the manufacturing method described above, since the recessed grooves are formed on one surface of the semiconductor light emitting devices, the luminance of the display device can be improved despite the simple manufacturing method.
On the other hand, the present invention is not necessarily limited to the above production method. As another example, after the second conductive type electrode 1152 is deposited in the recessed groove with the second conductive type semiconductor layer 1153 for each light emitting element, the second conductive type electrode 1152 is connected to the second conductive type electrode 1152 Two electrodes 1040 may be formed. As described above, the display device using the semiconductor light emitting element described above can be modified into various forms, and such modified examples will be described below.
Referring to FIG. 18, a display device 2000 using a passive matrix (PM) type semiconductor light emitting device as a display device 2000 using a semiconductor light emitting device is illustrated. However, the example described below is also applicable to an active matrix (AM) semiconductor light emitting device.
The display device 2000 includes a substrate 2010, a first electrode 2020, a second electrode 2040, and a plurality of semiconductor light emitting devices 2050. Here, the first electrode 2020 and the second electrode 2040 may include a plurality of electrode lines, respectively.
The substrate 2010 is a wiring substrate on which the first electrode 2020 is disposed, and may include polyimide (PI) to implement a flexible display device. In addition, any insulating and flexible material may be used.
The first electrode 2020 is disposed on the substrate 2010 and may be formed as a long bar electrode in one direction. The first electrode 1020 may serve as a data electrode. The second electrode 2040 is disposed on the opposite side of the first electrode with respect to the semiconductor light emitting element.
A plurality of semiconductor light emitting devices 2050 are coupled to the substrate 2010 and are electrically connected to the first electrode 2020 and the second electrode 2040. More specifically, a plurality of second electrodes 1040, which are arranged in a direction intersecting the longitudinal direction of the first electrode 1020 and are electrically connected to the semiconductor light emitting device 1050, are disposed between the semiconductor light emitting devices, do.
A plurality of semiconductor light emitting devices 2050 may form a plurality of rows in a direction parallel to a plurality of electrode lines provided in the first electrode 2020. [ However, the present invention is not limited thereto. For example, the plurality of semiconductor light emitting devices 2050 may form a plurality of rows along the second electrode 2040.
19, for example, the semiconductor light emitting device 2050 includes a first conductive type electrode 2156, a first conductive type semiconductor layer 2155 on which a first conductive type electrode 2156 is formed, The second conductivity type semiconductor layer 2153 formed on the active layer 2154 and the second conductive type semiconductor layer 2153 formed on the first conductivity type semiconductor layer 2155; And includes a conductive electrode 2152.
The first conductive type electrode 2156 and the first conductive type semiconductor layer 2155 may be a p-type electrode and a p-type semiconductor layer, respectively. The second conductive type electrode 2152 and the second conductive type semiconductor layer 2155 may be a p- Type semiconductor layer 2153 may be an n-type electrode and an n-type semiconductor layer, respectively. However, the present invention is not limited thereto, and the first conductivity type may be n-type and the second conductivity type may be p-type.
More specifically, the first conductive type electrode 2156 is formed on one surface of the first conductive type semiconductor layer 2155, and the active layer 2154 is formed on the other surface of the first conductive type semiconductor layer 2155, And the second conductive type electrode 2152 is formed on one surface of the second conductive type semiconductor layer 2153. The second conductive type semiconductor layer 2153 is formed on one surface of the second conductive type semiconductor layer 2153,
According to the illustrated example, the first conductive electrode 2156 contacts the first electrode 2020. The first conductive electrode 2156 is formed of at least one of TiO, Ti, Pt, and Au, and is in physical contact with the first electrode by pressurization. More specifically, the bonding conductive metal 2159 is disposed between the first electrode 2020 of the first conductive conductive electrode 2156, and the first conductive conductive electrode 2156 and the first conductive conductive electrode 21512 are disposed on both sides of the bonding metal. The first electrodes 2020 are brought into pressure contact with each other. In this case, since there is no conductive adhesive layer, the polyimide 2158 can be filled between the semiconductor light emitting elements.
In this case, the second conductive type electrode is disposed on one surface of the second conductive type semiconductor layer 2153, and an undoped semiconductor layer 2153a is formed on the other surface of the second conductive type semiconductor layer 2153 May be formed.
Referring to FIGS. 18 and 19, the second electrode 2040 and the second conductive electrode 2152 may be connected to each other by ohmic contact. For example, the second conductive electrode 2152 is formed of an ohmic electrode for ohmic contact, and the second electrode 2040 covers at least a part of the ohmic electrode by printing or vapor deposition.
At least one of the semiconductor light emitting devices may include a recessed groove formed in at least a part of the undoped semiconductor layer 2153a and the second conductive type semiconductor layer 2153. At least a part of the second conductive type electrode for supplying an electric signal to the semiconductor light emitting elements may be disposed in the recessed groove 2160 as a part of the wiring electrode.
Referring to these drawings, for example, the recess groove 2160 may have a bottom portion 2161 and a side wall portion 2162. The side wall part 2162 may be formed along the edge of the second conductivity type semiconductor layer 2153 to surround the bottom part 2161. In this case, the recessed recess 2160 is recessed from one surface of the undoped semiconductor layer 2153a toward the other surface, and a portion of the recessed recess 2160, except for the recessed recess 2160, .
The bottom portion 2161 is formed in the second conductivity type semiconductor layer and overlaps with the active layer. Also, the bottom portion 2161 is disposed parallel to one side of the undoped semiconductor layer 2153a, the side wall portion 2162 completely surrounds the bottom portion, and the shape corresponding to the rectangular annular shape &Lt; / RTI &gt;
The second conductive electrode 2152 may be formed to cover at least a part of the sidewall portion 2162. More specifically, the second conductive type electrode is formed to cover at least a part of the side wall portion 2162. In this case, the second conductive type electrode may be disposed at a side of the side wall portion 2162. For example, the side wall part 2162 has a pair of side walls parallel to each other, and the second conductive type electrode 2152 covers one of the pair of side walls and does not cover the other side .
The side wall portion may include another pair of side walls disposed perpendicular to the pair of side walls, and the second conductive electrode may be formed to cover a portion of the other pair of side walls. At this time, the other pair of sidewalls has a first sidewall and a second sidewall (not shown in Fig. 15B), and the second conductive-type electrode has the first sidewall, the bottom and the second sidewall A passing line can be formed. According to the well-shaped structure in which the recessed trench is formed in the second conductivity type semiconductor layer, the second conductive-type electrode and the second conductive-type semiconductor are formed at least on the side wall of the second conductive- The contact area of the layer becomes wider.
According to the embodiment, the side wall portion is inclined with respect to a direction perpendicular to the bottom portion. For example, the recessed groove may be formed such that the cross-sectional area of the recessed groove increases as the distance from the first conductive type semiconductor layer increases. Since the sidewall portion is inclined, the actual area of the sidewall portion may increase, and thus the contact area between the second conductive type electrode and the second conductive type semiconductor layer may be further increased.
Further, irregularities (not shown in FIG. 15A) may be formed on the surface of the bottom portion. The irregularities are formed in the size of micrometers, and can be formed at the time of etching the recessed groove due to the residue after the growth substrate and the second conductivity type semiconductor layer are separated.
The irregularities may be formed in at least a part of the side wall part, and the irregularities of the side wall part may be smaller than the irregularities of the bottom part. This is because a lot of irregularities corresponding to the shape of the residue can be formed on the bottom due to the influence of the residue. The contact area between the second conductive type electrode and the second conductivity type semiconductor layer is increased by the unevenness, and the light emitting surface of the semiconductor light emitting device can also be increased.
The above-described display device using the semiconductor light emitting device is not limited to the configuration and the method of the embodiments described above, but all or a part of the embodiments may be selectively combined so that various modifications may be made to the embodiments It is possible.
1. A display device comprising a plurality of semiconductor light emitting elements,
Wherein at least one of the semiconductor light-
A second conductivity type semiconductor layer overlapping the first conductivity type semiconductor layer; And
And an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer,
A recessed groove is formed in at least a part of the second conductivity type semiconductor layer,
Wherein the recessed groove has a bottom portion and a side wall portion formed along an edge of the second conductive type semiconductor layer and surrounding the bottom portion.
And at least a part of the wiring electrode for supplying an electric signal to the semiconductor light emitting elements is disposed in the recessed groove.
And the wiring electrode is formed to cover at least a part of the side wall portion.
The side wall portion has a pair of side walls parallel to each other,
Wherein the wiring electrode covers one of the pair of side walls and does not cover the other.
The side wall portion having another pair of side walls disposed perpendicularly to the pair of side walls,
And the wiring electrode is formed to cover a part of the other pair of side walls.
The other pair of side walls having a first sidewall and a second sidewall,
And the wiring electrode forms a line passing through the first side wall, the bottom and the second side wall in order.
Wherein the height of the sidewall portion is 10 to 20% of the length of one of the pair of sidewalls or 25 to 35% of the length of the portion of the first sidewall overlapping the wiring electrode.
Wherein the first conductivity type semiconductor layer is a P-type GaN layer, the second conductivity type semiconductor layer is an N-type GaN layer, and the recess groove is a portion in which at least a part of the N-type Gan layer is etched Display device.
Wherein the display device has a front surface on which time information is output,
And the N-type GaN layer is closer to the front surface than the P-type GaN layer.
At least one of the semiconductor light emitting devices further includes an undoped semiconductor layer formed to cover the second conductive type semiconductor layer,
And the recessed recess is recessed from the one surface of the undoped semiconductor layer toward the first conductive-type semiconductor layer.
Wherein the bottom portion is formed in the second conductivity type semiconductor layer, and the side wall portion is formed in the second conductivity type semiconductor layer and the undoped semiconductor layer.
Wherein a wiring electrode for supplying an electric signal to the semiconductor light emitting elements extends from one surface of the undoped semiconductor layer to the recessed groove.
And a concave and a convex are formed on a surface of the bottom portion.
Wherein the concavities and convexities are formed on at least a part of the side wall portion, and the concave and convex portions of the side wall portion are smaller in size than the concave and convex portions of the bottom portion.
Wherein the side wall portion is inclined with respect to a direction perpendicular to the bottom portion.
Wherein a cross-sectional area of the recessed groove increases as a distance from the first conductive type semiconductor layer increases due to an inclination of the side wall portion.
Wherein the recessed groove has a bottom portion and a side wall portion formed along an edge of the first conductivity type semiconductor layer and surrounding the bottom portion.
Wherein the second conductivity type semiconductor layer is an N-type GaN layer, and the recessed portion is an etched portion of at least a part of the N-type Gan layer.
Sequentially growing a second conductivity type semiconductor layer, an active layer and a first conductivity type semiconductor layer on the substrate so that the first conductivity type semiconductor layer, the active layer and the second conductivity type semiconductor layer are laminated;
Etching the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer to isolate the semiconductor light emitting elements on the substrate;
Separating the semiconductor light emitting device from the substrate;
Forming a recessed groove in the second conductive semiconductor layer through etching; And
And electrically connecting the second conductivity type semiconductor layer formed with the recessed groove to the wiring electrode.
KR1020150148965A 2015-10-26 2015-10-26 Display device using semiconductor light emitting device and method for manufacturing the same KR20170048066A (en)
KR1020150148965A KR20170048066A (en) 2015-10-26 2015-10-26 Display device using semiconductor light emitting device and method for manufacturing the same
PCT/KR2016/004286 WO2017073865A1 (en) 2015-10-26 2016-04-25 Display device using semiconductor light emitting device and method for manufacturing the same
US15/140,339 US9831222B2 (en) 2015-10-26 2016-04-27 Display device using semiconductor light emitting device and method for manufacturing the same
KR20170048066A true KR20170048066A (en) 2017-05-08
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