KR102233158B1 - Method for manufacturing display device using semiconductor light emitting diode - Google Patents

Abstract

In the method of manufacturing a display device according to an embodiment of the present invention, the semiconductor light emitting device formed on the growth substrate by bonding a growth substrate on which semiconductor light emitting devices are formed at predetermined intervals and a temporary substrate on which a sacrificial layer etched in a fluid is formed. Transferring them to the temporary substrate; Introducing into a fluid an acceptor substrate in which cells on which the semiconductor light emitting devices are mounted are formed at predetermined intervals; Aligning the temporary substrate in the fluid so that the sacrificial layer faces the acceptor substrate; Applying power to at least one of the temporary substrate and the acceptor substrate to form an electric field for moving the semiconductor light emitting devices; And mounting the semiconductor light emitting devices separated from the temporary substrate on the cells formed on the acceptor substrate, wherein the semiconductor light emitting devices maintain the same distance as the distance formed on the growth substrate, and It is characterized in that it is seated on the Scepter substrate.

Description

Manufacturing method of display device using semiconductor light emitting device {METHOD FOR MANUFACTURING DISPLAY DEVICE USING SEMICONDUCTOR LIGHT EMITTING DIODE}

The present invention relates to a method of manufacturing a display device using a semiconductor light emitting device having a size of several to tens of μm.

Recently, liquid crystal displays (LCDs), organic light-emitting device (OLED) displays, and micro LED displays are competing in the field of display technology to implement large-area displays.

On the other hand, if a semiconductor light emitting device (micro LED) having a diameter or cross-sectional area of 100 μm or less is used in the display, since the display does not absorb light using a polarizing plate or the like, very high efficiency can be provided. However, since a large display requires millions of semiconductor light emitting devices, it is difficult to transfer devices compared to other technologies.

delete

Technologies currently being developed for the transfer process include pick & place, laser lift-off (LLO), or self-assembly. Among them, the self-assembly method is a method in which the semiconductor light emitting device locates itself in a fluid, and is the most advantageous method for realizing a large-screen display device.

Meanwhile, in the self-assembly method, there are a method of assembling a semiconductor light emitting device directly to a final substrate (or wiring board) on which wiring is formed, and a method of assembling the semiconductor light emitting device to an assembly substrate and then transferring it to the final substrate through an additional transfer process. The method of assembling directly on the final substrate is efficient in terms of the process, and in the case of using the assembled substrate, there is an advantage in that a structure for self-assembly can be added without limitation, so two methods are selectively used.

An object of the present invention is to provide a method of manufacturing a display device capable of transferring semiconductor light emitting devices formed at predetermined intervals on a growth substrate to a wiring board or an assembly board by a self-assembly method, while maintaining the intervals. It is done.

In the method of manufacturing a display device according to an embodiment of the present invention, the semiconductor light emitting device formed on the growth substrate by bonding a growth substrate on which semiconductor light emitting devices are formed at predetermined intervals and a temporary substrate on which a sacrificial layer etched in a fluid is formed. Transferring them to the temporary substrate; Introducing into a fluid an acceptor substrate in which cells on which the semiconductor light emitting devices are mounted are formed at predetermined intervals; Aligning the temporary substrate in the fluid so that the sacrificial layer faces the acceptor substrate; Applying power to at least one of the temporary substrate and the acceptor substrate to form an electric field for moving the semiconductor light emitting devices; And mounting the semiconductor light emitting devices separated from the temporary substrate on the cells formed on the acceptor substrate, wherein the semiconductor light emitting devices maintain the same distance as the distance formed on the growth substrate, and It is characterized in that it is seated on the Scepter substrate.

In this embodiment, at least the semiconductor light emitting devices fixed to the temporary substrate are arranged to face the cells formed on the acceptor substrate.

In this embodiment, the acceptor substrate includes at least one of a first assembly electrode and a second assembly electrode that forms an electric field when power is applied, and is an assembly substrate temporarily accommodating the semiconductor light emitting devices, or the semiconductor light emitting device It is characterized in that it is a wiring board on which driving electrodes for driving the elements are formed.

In this embodiment, the temporary substrate includes a third assembly electrode that forms an electric field for moving the semiconductor light emitting elements in cooperation with the first assembly electrode or the second assembly electrode of the acceptor substrate when power is applied, and , The third assembly electrode is characterized in that it is formed of a transparent conductive material.

In this embodiment, the first assembly electrode and the second assembly electrode are formed to be parallel to each other.

In this embodiment, the driving electrode includes a metal solder electrically connected to the semiconductor light emitting devices, and the wiring board is characterized in that at least a part of the metal solder is exposed on a bottom surface of the cell. .

In this embodiment, the temporary substrate includes an auxiliary bonding layer formed of a photosensitive material under the sacrificial layer.

In this embodiment, the sacrificial layer is formed of a photosensitive material and includes an exposed region etched in the fluid and a non-exposed region not etched in the fluid, and at least some of the semiconductor light emitting devices are fixed to the exposed region. It is done.

In the present embodiment, after the transfer of the semiconductor light emitting devices fixed to the temporary substrate is completed, the step of discharging the fluid to the side where the acceptor substrate is disposed is further included.

In this embodiment, when the acceptor substrate is the assembly substrate, after transfer of the semiconductor light emitting devices fixed to the temporary substrate is completed, the step of applying an adhesive material to the assembly substrate is selectively included. do.

In this embodiment, the semiconductor light emitting devices include a blue semiconductor light emitting device emitting blue light, a green semiconductor light emitting device emitting green light, and a red semiconductor light emitting device emitting red light.

In the method of manufacturing a display device according to an embodiment of the present invention, since the semiconductor light emitting devices formed on the temporary substrate are transferred to the acceptor substrate while maintaining the spacing, a specific semiconductor light emitting device is positioned at a specific position through alignment of the temporary substrate and the acceptor substrate. It has a possible effect to settle in the cell of.

In addition, the self-assembly of the semiconductor light emitting devices formed on the temporary substrate is simultaneously performed, thereby improving the efficiency of the process, and minimizing the moving distance of the semiconductor light emitting devices to prepare for loss and damage of the semiconductor light emitting devices.

1 is a conceptual diagram showing an embodiment of a display device using a semiconductor light emitting device of the present invention.
FIG. 2 is a partially enlarged view of portion A of the display device of FIG. 1.
3 is an enlarged view of the semiconductor light emitting device of FIG. 2.
4 is an enlarged view showing another embodiment of the semiconductor light emitting device of FIG. 2.
5A to 5E are conceptual diagrams for explaining a new process of manufacturing the above-described semiconductor light emitting device.
6 is a conceptual diagram showing an example of a self-assembly device of a semiconductor light emitting device according to the present invention.
7 is a block diagram of the self-assembly device of FIG. 6.
8A to 8E are conceptual diagrams illustrating a process of self-assembling a semiconductor light emitting device using the self-assembly device of FIG. 6.
9 is a conceptual diagram illustrating the semiconductor light emitting device of FIGS. 8A to 8E.
10 is a diagram schematically showing a self-assembly process according to the present invention.
11 is a diagram illustrating an arrangement of subpixels and pixels on an acceptor substrate according to an embodiment of the present invention.
12A to 12C are views showing a self-assembly process according to an embodiment (wiring substrate) of the present invention.
13A to 13C are views showing a self-assembly process according to another embodiment (assembled substrate) of the present invention.
14A to 14D are views showing the structure of a temporary substrate according to an embodiment of the present invention.
15 is a view showing a self-assembly process using the temporary substrate according to FIG. 14D.
16 is a view showing an assembly electrode formed on an assembly substrate according to an embodiment of the present invention.
17 is a diagram illustrating a process from a manufacturing step of a semiconductor light emitting device to a transfer step to a temporary substrate as a pre-process of the self-assembly process according to an embodiment of the present invention.
18 is a view showing a post-process of the self-assembly process according to an embodiment of the present invention.
19 is a view showing a post-process of a self-assembly process according to another embodiment of the present invention.

Hereinafter, exemplary embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but identical or similar elements are denoted by the same reference numerals regardless of reference numerals, and redundant descriptions thereof will be omitted. The suffixes “module” and “unit” for the constituent elements used in the following description are given or used interchangeably in consideration of only the ease of preparation of the specification, and do not themselves have a distinct meaning or role from each other. In addition, in describing the embodiments disclosed in the present specification, when it is determined that a detailed description of related known technologies may obscure the subject matter of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed in the present specification is not to be construed as being limited by the accompanying drawings. Also, when an element such as a layer, region, or substrate is referred to as being “on” another component, it can be understood that it may exist directly on the other element, or intermediate elements may exist between them. There will be.

Display devices described herein include 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 system, and a slate PC. (slate PC), tablet PC (tablet PC), ultra book (ultra book), digital TV (digital TV), desktop computer (desktop computer), and the like may be included. However, the configuration according to the embodiment described in the present specification may be applied even if a new product type to be developed later can include a display.

1 is a conceptual diagram showing an embodiment of a display device using a semiconductor light emitting device of the present invention, FIG. 2 is a partial enlarged view of part A of the display device of FIG. 1, and FIG. 3 is an enlarged view of the semiconductor light emitting device of FIG. And FIG. 4 is an enlarged view showing another embodiment of the semiconductor light emitting device of FIG. 2.

As illustrated, information processed by the controller of the display device 100 may be output from the display module 140. A case 101 in a closed loop shape surrounding an edge of the display module may form a bezel of the display device.

The display module 140 includes a panel 141 on which an image is displayed, and the panel 141 includes a micro-sized semiconductor light emitting device 150 and a wiring board 110 on which the semiconductor light emitting device 150 is mounted. It can be provided.

A wiring is formed on the wiring board 110 to be connected to the n-type electrode 152 and the p-type electrode 156 of the semiconductor light emitting device 150. Through this, the semiconductor light emitting device 150 may be provided on the wiring board 110 as an individual pixel that emits light.

The image displayed on the panel 141 is visual information, and is implemented by independently controlling light emission of sub-pixels arranged in a matrix form through the wiring.

In the present invention, a micro LED (Light Emitting Diode) is exemplified as a kind of semiconductor light emitting device 150 that converts current into light. The micro LED may be a light emitting diode formed in a small size of 100 microns or less. In the semiconductor light emitting device 150, blue, red, and green are respectively provided in the emission region, and a unit pixel may be implemented by a combination thereof. That is, the unit pixel means a minimum unit for implementing one color, and at least three micro LEDs may be provided in the unit pixel.

More specifically, referring to FIG. 3, the semiconductor light emitting device 150 may have a vertical structure.

For example, the semiconductor light emitting device 150 is mainly made of gallium nitride (GaN), and indium (In) and/or aluminum (Al) are added together to be implemented as a high-power light emitting device that emits various light including blue. Can be.

Such a vertical semiconductor light emitting device includes a p-type electrode 156, a p-type semiconductor layer 155 formed on the p-type electrode 156, an active layer 154 formed on the p-type semiconductor layer 155, and an active layer 154. And an n-type semiconductor layer 153 formed thereon, and an n-type electrode 152 formed on the n-type semiconductor layer 153. In this case, the p-type electrode 156 located at the bottom may be electrically connected to the p electrode of the wiring board, and the n-type electrode 152 located at the top may be electrically connected to the n electrode at the top of the semiconductor light emitting device. The vertical semiconductor light emitting device 150 has a great advantage of reducing a chip size because electrodes can be arranged up and down.

As another example, referring to FIG. 4, the semiconductor light emitting device may be a flip chip type light emitting device.

As such an example, the semiconductor light emitting device 250 includes a p-type electrode 256, a p-type semiconductor layer 255 on which the p-type electrode 256 is formed, and 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 disposed horizontally apart from the p-type electrode 256 on the n-type semiconductor layer 253. In this case, both the p-type electrode 256 and the n-type electrode 152 may be electrically connected to the p-electrode and the n-electrode of the wiring board under the semiconductor light emitting device.

Each of the vertical semiconductor light emitting device and the horizontal semiconductor light emitting device may be a green semiconductor light emitting device, a blue semiconductor light emitting device, or a red semiconductor light emitting device. In the case of green and blue semiconductor light emitting devices, gallium nitride (GaN) is mainly used, and indium (In) and/or aluminum (Al) are added together to embody green or blue light. Can be. As such an example, the semiconductor light emitting device may be a gallium nitride thin film formed in various layers such as n-Gan, p-Gan, AlGaN, InGan, and specifically, the p-type semiconductor layer is P-type GaN, and the n The type semiconductor layer may be N-type GaN. However, in the case of a red semiconductor light emitting device, the p-type semiconductor layer may be P-type GaAs, and the n-type semiconductor layer may be N-type GaAs.

Further, the p-type semiconductor layer may be P-type GaN doped with Mg at the p-electrode side, and the n-type semiconductor layer may be N-type GaN doped with Si at the n-electrode side. In this case, the above-described semiconductor light emitting devices may be semiconductor light emitting devices without an active layer.

Meanwhile, referring to FIGS. 1 to 4, since the light emitting diode is very small, unit pixels that emit light may be arranged in a high-definition manner in the display panel, thereby implementing a high-definition display device.

In the display device using the semiconductor light emitting device of the present invention described above, a semiconductor light emitting device grown on a wafer and formed through mesa and isolation is used as an individual pixel. In this case, the micro-sized semiconductor light emitting device 150 must be transferred to a wafer to a predetermined position on the substrate of the display panel. There is pick and place as such transfer technology, but the success rate is low and very long time is required. As another example, there is a technique of transferring several elements at once using a stamp or a roll, but there is a limit to the yield, so it is not suitable for a large screen display. In the present invention, a new manufacturing method and manufacturing apparatus for a display device capable of solving this problem are proposed.

To this end, hereinafter, first, a new method of manufacturing a display device will be described. 5A to 5E are conceptual diagrams for explaining a new process of manufacturing the above-described semiconductor light emitting device.

In the present specification, a display device using a passive matrix (PM) type semiconductor light emitting device is exemplified. However, the example described below is applicable to an active matrix (AM) type semiconductor light emitting device. In addition, a method of self-assembling a horizontal type semiconductor light emitting device is illustrated, but this is applicable to a method of self-assembling a vertical type semiconductor light emitting device.

First, according to the manufacturing method, a first conductive type semiconductor layer 153, an active layer 154, and a second conductive type semiconductor layer 155 are respectively grown on the growth substrate 159 (FIG. 5A).

When the first conductive type semiconductor layer 153 is grown, next, an active layer 154 is grown on the first conductive type semiconductor layer 153, and then a second conductive type semiconductor is formed on the active layer 154. The layer 155 is grown. In this way, when the first conductive type semiconductor layer 153, the active layer 154, and the second conductive type semiconductor layer 155 are sequentially grown, as shown in FIG. 5A, the first conductive type semiconductor layer 153 , The active layer 154 and the second conductive semiconductor layer 155 form a stacked structure.

In this case, the first conductive type semiconductor layer 153 may be a p-type semiconductor layer, and the second conductive type semiconductor layer 155 may be an n-type semiconductor layer. However, the present invention is not necessarily limited thereto, and an example in which the first conductivity type is n-type and the second conductivity type is p-type is also possible.

In addition, although the present embodiment illustrates a case in which the active layer is present, as described above, a structure without the active layer may be possible depending on the case. As such an example, the p-type semiconductor layer may be P-type GaN doped with Mg, and the n-type semiconductor layer may be N-type GaN doped with Si on the n-electrode side.

The growth substrate 159 (wafer) may be formed of a material having a light-transmitting property, for example, any one of sapphire (Al2O3), GaN, ZnO, and AlO, but is not limited thereto. In addition, the growth substrate 1059 may be formed of a material suitable for growth of semiconductor materials or a carrier wafer. It can be formed of a material having excellent thermal conductivity, including a conductive substrate or an insulating substrate, for example, a SiC substrate having a higher thermal conductivity than a sapphire (Al2O3) substrate, or at least one of Si, GaAs, GaP, InP, and Ga2O3. Can be used.

Next, at least a portion of the first conductive type semiconductor layer 153, the active layer 154, and the second conductive type semiconductor layer 155 is removed to form a plurality of semiconductor light emitting devices (FIG. 5B).

More specifically, isolation is performed so that a plurality of light emitting devices form a light emitting device array. That is, the first conductive type semiconductor layer 153, the active layer 154, and the second conductive type semiconductor layer 155 are vertically etched to form a plurality of semiconductor light emitting devices.

If, in the case of forming a horizontal type semiconductor light emitting device, the active layer 154 and the second conductive type semiconductor layer 155 are partially removed in the vertical direction, so that the first conductive type semiconductor layer 153 goes to the outside. The exposed mesa process and the isolation of forming a plurality of semiconductor light emitting device arrays by etching the first conductive type semiconductor layer thereafter may be performed.

Next, a second conductive type electrode 156 (or a p-type electrode) is formed on one surface of the second conductive type semiconductor layer 155 (FIG. 5C). The second conductive electrode 156 may be formed by a deposition method such as sputtering, but the present invention 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 type electrode 156 may be an n-type electrode.

Then, the growth substrate 159 is removed to provide a plurality of semiconductor light emitting devices. For example, the growth substrate 1059 may be removed using a laser lift-off method (LLO) or a chemical lift-off method (CLO) (FIG. 5D).

Thereafter, a step in which the semiconductor light emitting devices 150 are seated on a substrate in a chamber filled with a fluid is performed (FIG. 5E).

For example, the semiconductor light emitting devices 150 and a substrate are placed in a chamber filled with a fluid, and the semiconductor light emitting devices are self-assembled to the substrate 1061 using flow, gravity, and surface tension. In this case, the substrate may be an assembled substrate 161.

As another example, it is possible to put a wiring board in the fluid chamber instead of the assembly board 161 so that the semiconductor light emitting devices 150 are directly seated on the wiring board. In this case, the substrate may be a wiring substrate. However, for convenience of explanation, the present invention illustrates that the substrate is provided as the assembly substrate 161 and the semiconductor light emitting devices 1050 are mounted thereon.

Cells (not shown) into which the semiconductor light emitting devices 150 are inserted may be provided on the assembly substrate 161 to facilitate mounting of the semiconductor light emitting devices 150 on the assembly substrate 161. Specifically, cells in which the semiconductor light emitting devices 150 are mounted are formed on the assembly substrate 161 at a position where the semiconductor light emitting devices 150 are aligned with a wiring electrode. The semiconductor light emitting devices 150 are assembled in the cells while moving in the fluid.

After a plurality of semiconductor light emitting elements are arrayed on the assembled substrate 161, when the semiconductor light emitting elements of the assembled substrate 161 are transferred to a wiring board, a large area can be transferred. Accordingly, the assembled substrate 161 may be referred to as a temporary substrate.

Meanwhile, in order to apply the self-assembly method described above to manufacturing a large screen display, the transfer yield must be increased. The present invention proposes a method and apparatus for minimizing the influence of gravity or friction and preventing non-specific binding in order to increase the transfer yield.

In this case, in the display device according to the present invention, a magnetic material is disposed on the semiconductor light emitting device to move the semiconductor light emitting device using magnetic force, and the semiconductor light emitting device is seated at a predetermined position using an electric field during the moving process. Hereinafter, such a transfer method and apparatus will be described in more detail together with the accompanying drawings.

6 is a conceptual diagram illustrating an example of a self-assembly device of a semiconductor light emitting device according to the present invention, and FIG. 7 is a block diagram of the self-assembly device of FIG. 6. In addition, FIGS. 8A to 8D are conceptual diagrams illustrating a process of self-assembling a semiconductor light emitting device using the self-assembling device of FIG. 6, and FIG. 9 is a conceptual diagram illustrating the semiconductor light emitting device of FIGS. 8A to 8D.

6 and 7, the self-assembly device 160 of the present invention may include a fluid chamber 162, a magnet 163, and a position control unit 164.

The fluid chamber 162 has a space for accommodating a plurality of semiconductor light emitting devices. The space may be filled with a fluid, and the fluid may contain water or the like as an assembly solution. Accordingly, the fluid chamber 162 may be a water tank, and may be configured in an open type. However, the present invention is not limited thereto, and the fluid chamber 162 may be a closed type in which the space is a closed space.

In the fluid chamber 162, a substrate 161 may be disposed such that an assembly surface on which the semiconductor light emitting devices 150 are assembled faces downward. For example, the substrate 161 is transferred to an assembly position by a transfer unit, and the transfer unit may include a stage 165 on which the substrate is mounted. The stage 165 is positioned by a control unit, through which the substrate 161 may be transferred to the assembly position.

At this time, the assembly surface of the substrate 161 faces the bottom of the fluid chamber 150 at the assembly position. As illustrated, the assembly surface of the substrate 161 is disposed to be immersed in the fluid in the fluid chamber 162. Accordingly, the semiconductor light emitting device 150 moves to the assembly surface in the fluid.

The substrate 161 is an assembled substrate capable of forming an electric field, and may include a base portion 161a, a dielectric layer 161b, and a plurality of electrodes 161c.

The base portion 161a is made of an insulating material, and the plurality of electrodes 161c may be a thin film or thick bi-planar electrode patterned on one surface of the base portion 161a. The electrode 161c may be formed of, for example, a stack of Ti/Cu/Ti, Ag paste, and ITO.

The dielectric layer 161b may be made of an inorganic material such as SiO2, SiNx, SiON, Al2O3, TiO2, and HfO2. Alternatively, the dielectric layer 161b may be formed of a single layer or a multilayer as an organic insulator. The dielectric layer 161b may have a thickness of several tens of nm to several μ\μm.

Furthermore, the substrate 161 according to the present invention includes a plurality of cells 161d partitioned by a partition wall. The cells 161d are sequentially disposed in one direction, and may be made of a polymer material. In addition, the partition wall 161e constituting the cells 161d is made to be shared with the neighboring cells 161d. The partition wall 161e protrudes from the base portion 161a, and the cells 161d may be sequentially disposed in one direction by the partition wall 161e. More specifically, the cells 161d are sequentially arranged in column and row directions, respectively, and may have a matrix structure.

Inside the cells 161d, as illustrated, a groove for accommodating the semiconductor light emitting device 150 may be provided, and the groove may be a space defined by the partition wall 161e. The shape of the groove may be the same or similar to the shape of the semiconductor light emitting device. For example, when the semiconductor light emitting device has a square shape, the groove may have a square shape. Further, although not shown, when the semiconductor light emitting device is circular, grooves formed inside the cells may be circular. Furthermore, each of the cells is made to accommodate a single semiconductor light emitting device. That is, one semiconductor light emitting device is accommodated in one cell.

Meanwhile, the plurality of electrodes 161c may include a plurality of electrode lines disposed on the bottom of each of the cells 161d, and the plurality of electrode lines may extend to neighboring cells.

The plurality of electrodes 161c are disposed under the cells 161d, and different polarities are respectively applied to generate an electric field in the cells 161d. In order to form the electric field, the dielectric layer may form the bottom of the cells 161d while the dielectric layer covers the plurality of electrodes 161c. In this structure, when different polarities are applied to the pair of electrodes 161c under each of the cells 161d, an electric field is formed, and the semiconductor light emitting device can be inserted into the cells 161d by the electric field. have.

At the assembly position, the electrodes of the substrate 161 are electrically connected to the power supply unit 171. The power supply unit 171 performs a function of generating the electric field by applying power to the plurality of electrodes.

As illustrated, the self-assembly device may include a magnet 163 for applying magnetic force to the semiconductor light emitting devices. The magnet 163 is disposed to be spaced apart from the fluid chamber 162 to apply a magnetic force to the semiconductor light emitting devices 150. The magnet 163 may be disposed to face the opposite surface of the assembly surface of the substrate 161, and the position of the magnet is controlled by a position control unit 164 connected to the magnet 163.

The semiconductor light emitting device 1050 may include a magnetic material to move in the fluid by the magnetic field of the magnet 163.

Referring to FIG. 9, a semiconductor light emitting device including a magnetic material includes a first conductive type electrode 1052 and a second conductive type electrode 1056, and a first conductive type semiconductor layer on which the first conductive type electrode 1052 is disposed. (1053), a second conductive type semiconductor layer 1055 overlapping with the first conductive type semiconductor layer 1052 and on which the second conductive type electrode 1056 is disposed, and the first and second conductive type semiconductors An active layer 1054 disposed between the layers 1053 and 1055 may be included.

Here, the first conductivity type is p-type, the second conductivity type may be n-type, and vice versa. In addition, as described above, it may be a semiconductor light emitting device without the active layer.

Meanwhile, in the present invention, the first conductive type electrode 1052 may be generated after the semiconductor light emitting device is assembled to the wiring board by self-assembly of the semiconductor light emitting device. In addition, in the present invention, the second conductive type electrode 1056 may include the magnetic material. The magnetic material may mean a metal exhibiting magnetism. The magnetic material may be Ni, SmCo, or the like, and as another example, may include a material corresponding to at least one of Gd-based, La-based, and Mn-based.

The magnetic material may be provided on the second conductive electrode 1056 in the form of particles. Also, differently, in the conductive type electrode including a magnetic material, one layer of the conductive type electrode may be formed of a magnetic material. As such an example, as shown in FIG. 9, the second conductive type electrode 1056 of the semiconductor light emitting device 1050 may include a first layer 1056a and a second layer 1056b. Here, the first layer 1056a may be formed to include a magnetic material, and the second layer 1056b may include a metal material other than a magnetic material.

As illustrated, in the present example, the first layer 1056a including a magnetic material may be disposed to contact the second conductivity type semiconductor layer 1055. In this case, the first layer 1056a is disposed between the second layer 1056b and the second conductive semiconductor layer 1055. The second layer 1056b may be a contact metal connected to the second electrode of the wiring board. However, the present invention is not necessarily limited thereto, and the magnetic material may be disposed on one surface of the first conductive type semiconductor layer.

Referring back to FIGS. 6 and 7, more specifically, the self-assembly device includes a magnetic handler that can be automatically or manually moved in the x, y, z axis on the top of the fluid chamber, or the magnet 163 It may be provided with a motor capable of rotating. The magnet handler and the motor may constitute the position control unit 164. Through this, the magnet 163 rotates in a horizontal direction, a clockwise direction, or a counterclockwise direction with the substrate 161.

Meanwhile, a light-transmitting bottom plate 166 is formed in the fluid chamber 162, and the semiconductor light emitting devices may be disposed between the bottom plate 166 and the substrate 161. The image sensor 167 may be disposed to face the bottom plate 166 so as to monitor the inside of the fluid chamber 162 through the bottom plate 166. The image sensor 167 is controlled by the control unit 172 and may include an inverted type lens and a CCD so that the assembly surface of the substrate 161 can be observed.

The self-assembly device described above is made to use a combination of a magnetic field and an electric field, and if this is used, the semiconductor light emitting devices are seated at a predetermined position on the substrate by the electric field in the process of moving by the position change of the magnet. I can. Hereinafter, the assembly process using the self-assembly device described above will be described in more detail.

First, a plurality of semiconductor light emitting devices 1050 including magnetic materials are formed through the process described in FIGS. 5A to 5C. In this case, in the process of forming the second conductive type electrode of FIG. 5C, a magnetic material may be deposited on the semiconductor light emitting device.

Next, the substrate 161 is transferred to the assembly position, and the semiconductor light emitting devices 1050 are put into the fluid chamber 162 (FIG. 8A).

As described above, the assembly position of the substrate 161 may be a position disposed in the fluid chamber 162 such that the assembly surface on which the semiconductor light emitting devices 1050 of the substrate 161 are assembled faces downward. I can.

In this case, some of the semiconductor light emitting devices 1050 may sink to the bottom of the fluid chamber 162 and some may float in the fluid. When the light-transmitting bottom plate 166 is provided in the fluid chamber 162, some of the semiconductor light emitting devices 1050 may sink to the bottom plate 166.

Next, a magnetic force is applied to the semiconductor light emitting devices 1050 so that the semiconductor light emitting devices 1050 rise in the vertical direction within the fluid chamber 162 (FIG. 8B).

When the magnet 163 of the self-assembly device moves from its original position to a surface opposite to the assembly surface of the substrate 161, the semiconductor light emitting devices 1050 rise in the fluid toward the substrate 161. The original position may be a position away from the fluid chamber 162. As another example, the magnet 163 may be composed of an electromagnet. In this case, electricity is supplied to the electromagnet to generate an initial magnetic force.

Meanwhile, in this example, when the magnitude of the magnetic force is adjusted, a separation distance between the assembly surface of the substrate 161 and the semiconductor light emitting devices 1050 may be controlled. For example, the separation distance is controlled using the weight, buoyancy, and magnetic force of the semiconductor light emitting devices 1050. The separation distance may be several millimeters to tens of micrometers from the outermost surface of the substrate.

Next, magnetic force is applied to the semiconductor light emitting devices 1050 so that the semiconductor light emitting devices 1050 move in one direction within the fluid chamber 162. For example, the magnet 163 is moved in a direction horizontal to the substrate, in a clockwise direction, or in a counterclockwise direction (FIG. 8C). In this case, the semiconductor light emitting devices 1050 move in a direction horizontal to the substrate 161 at a position spaced apart from the substrate 161 by the magnetic force.

Next, the step of inducing the semiconductor light emitting devices 1050 to the preset positions by applying an electric field so that the semiconductor light emitting devices 1050 are settled at a preset position of the substrate 161 during the movement of the semiconductor light emitting devices 1050 It proceeds (Fig. 8C). For example, while the semiconductor light emitting devices 1050 are moving in a direction horizontal to the substrate 161, they are moved in a direction perpendicular to the substrate 161 by the electric field. It is settled in the set position.

More specifically, power is supplied to the bi-planar electrode of the substrate 161 to generate an electric field, and by using this, the assembly is induced only at a predetermined position. That is, by using the selectively generated electric field, the semiconductor light emitting devices 1050 are self-assembled to the assembly position of the substrate 161. To this end, cells to which the semiconductor light emitting devices 1050 are inserted may be provided on the substrate 161.

Thereafter, the unloading process of the substrate 161 is performed, and the assembly process is completed. When the substrate 161 is an assembly substrate, a post-process for implementing a display device may be performed by transferring the arranged semiconductor light emitting devices to a wiring board as described above.

Meanwhile, after inducing the semiconductor light emitting devices 1050 to the preset position, the magnets so that the semiconductor light emitting devices 1050 remaining in the fluid chamber 162 fall to the bottom of the fluid chamber 162. The 163 may be moved in a direction away from the substrate 161 (FIG. 8D). As another example, when the power supply is stopped when the magnet 163 is an electromagnet, the semiconductor light emitting devices 1050 remaining in the fluid chamber 162 fall to the bottom of the fluid chamber 162.

Thereafter, when the semiconductor light emitting devices 1050 on the bottom of the fluid chamber 162 are recovered, the recovered semiconductor light emitting devices 1050 can be reused.

The self-assembly device and method described above focuses distant parts near a predetermined assembly site using a magnetic field to increase assembly yield in a fluidic assembly, and applies a separate electric field to the assembly site to selectively select parts only at the assembly site. Let it be assembled. At this time, the assembly board is placed on the top of the water tank and the assembly surface faces down, minimizing the effect of gravity caused by the weight of the parts, and preventing non-specific binding to eliminate defects. That is, in order to increase the transfer yield, the assembly substrate is placed on the top to minimize the effect of gravity or friction, and prevent non-specific binding.

As described above, according to the present invention having the above configuration, in a display device in which individual pixels are formed as semiconductor light emitting devices, a large number of semiconductor light emitting devices can be assembled at once.

As described above, according to the present invention, it is possible to pixelate a semiconductor light emitting device in a large amount on a small-sized wafer and then transfer it to a large area substrate. Through this, it is possible to manufacture a large-area display device at low cost.

On the other hand, the present invention provides a structure and method of an assembled substrate for increasing the yield of the above-described self-assembly process and the process yield after self-assembly. The present invention is limited to when the substrate 161 is used as an assembly substrate. That is, the assembly board to be described later is not used as a wiring board of a display device. Accordingly, hereinafter, the substrate 161 is referred to as an assembly substrate 161.

The present invention improves the process yield from two perspectives. First, according to the present invention, a strong electric field is formed at an undesired position, preventing the semiconductor light emitting device from being seated at an undesired position. Second, the present invention prevents the semiconductor light emitting elements from remaining on the assembly substrate when transferring the semiconductor light emitting elements mounted on the assembly substrate to another substrate.

In the present invention, a self-assembly method different from the self-assembly method (FIGS. 8A to 8E) using the electric and magnetic fields described above is proposed.

According to the above-described self-assembly method, the semiconductor light emitting devices 1050 randomly injected into the fluid formed a dummy made of a plurality of semiconductor light emitting devices 1050 and moved together along the moving direction of the magnetic field. The semiconductor light emitting devices 1050 were seated inside each cell 161d by being attracted to an electric field strongly formed inside the cell 161d.

That is, in the above-described self-assembly method, since the moving direction of the semiconductor light emitting devices 1050 is determined by the magnetic field, the semiconductor light emitting devices 1050 are simultaneously assembled to all cells 161d or specified in a specific cell 161d. The semiconductor light emitting device 1050 could not be assembled.

The present invention relates to a substrate-to-substrate self-assembly method, in which semiconductor light emitting devices 1100 provided on a first substrate are simultaneously transferred to a second substrate, but the distance between the semiconductor light emitting devices is a first substrate and a second substrate. It relates to a self-assembly method that is kept constant on the substrate.

Here, the first substrate is a donor substrate that provides the semiconductor light emitting devices 1100 and may be a temporary substrate 2000, and the second substrate is wired as an acceptor substrate (A) accommodating the semiconductor light emitting devices 1100. It may be a substrate 3000 or an assembly substrate 4000. A detailed description of each substrate will be described later.

10 is a diagram schematically showing a self-assembly process according to the present invention, and the self-assembly process according to the present invention may largely include the following steps.

First, as shown in FIGS. 10A and 10B, a growth substrate 1000 on which semiconductor light emitting devices 1100 are formed at predetermined intervals, and a temporary substrate 2000 on which a sacrificial layer 2100 etched in a fluid is formed. After bonding, a step of transferring the semiconductor light emitting devices 1100 formed on the growth substrate 1000 to the temporary substrate 2000 may be performed.

Specifically, one surface of the growth substrate 1000 on which the semiconductor light emitting devices 1100 are formed and one surface of the temporary substrate 2000 on which the sacrificial layer 2100 is formed are pressed together to form the semiconductor light emitting devices 1100 on the growth substrate ( 1000) may be transferred to the sacrificial layer 2100 of the temporary substrate 2000, and the spacing of the semiconductor light emitting devices 1100 may be kept the same.

In addition, the sacrificial layer 2100 may be formed of a material having excellent adhesion or bonding strength compared to the growth substrate 1000, whereby the semiconductor light emitting devices 1100 formed on the growth substrate 1000 can be easily used as the temporary substrate 2000. Can be transferred.

Next, as shown in FIG. 10(c), an acceptor substrate in which cells on which the semiconductor light emitting devices 1100 are seated is formed at predetermined intervals is introduced into the fluid L, and then the temporary substrate 2000 is introduced into the fluid. After the alignment with respect to the acceptor substrate may be performed.

In this case, the temporary substrate 2000 may be aligned in a fluid such that the sacrificial layer 2100 to which the semiconductor light emitting devices 1100 transferred from the growth substrate 1000 are fixed faces the acceptor substrate, and the sacrificial layer 2100 One surface of the acceptor substrate facing) may be a surface in which a cell on which the semiconductor light emitting devices 1100 are to be mounted is formed.

In addition, all of the semiconductor light emitting devices 1100 fixed to at least the temporary substrate 2000 may be aligned to face cells formed on the acceptor substrate. In other words, some cells may not face the semiconductor light emitting device 1100, but at least all of the semiconductor light emitting devices 1100 fixed to the temporary substrate 2000 may be aligned to face the cells.

In addition, it is preferable that the temporary substrate 2000 and the acceptor substrate are aligned so as not to contact each other while maintaining a state as close to each other as possible in the fluid.

Next, as shown in FIG. 10(d), the step of forming an electric field for moving the semiconductor light emitting devices 1100 by applying power to at least one of the temporary substrate 2000 and the acceptor substrate is performed. I can.

Power may be applied to both the temporary substrate 2000 and the acceptor substrate (formation of an electric field in the vertical direction) or may be applied only to the acceptor substrate (formation of an electric field in the horizontal direction). In each case, the structure of the temporary substrate 2000 and the type of the acceptor substrate may be different, and details related thereto will be described later.

Finally, as shown in FIG. 10E, a step of mounting the semiconductor light emitting devices 1100 separated from the temporary substrate 2000 on cells formed on the acceptor substrate may be performed.

The semiconductor light emitting devices 1100 may be separated from the temporary substrate 2000 as the sacrificial layer 2100 to which the semiconductor light emitting devices 1100 are fixed is etched in a fluid, and dielectrophoretic force is generated by the formed electric field. force) to move from the temporary substrate 2000 to the acceptor substrate, and may be seated on the facing cell.

In addition, since the temporary substrate 2000 and the acceptor substrate are arranged as close to each other as possible, the semiconductor light emitting devices 1100 can be mounted on the acceptor substrate while maintaining the same distance as the fixed distance to the temporary substrate 2000. .

Next, various embodiments of the temporary substrate 2000 will be described with reference to FIGS. 14 and 15.

14A to 14D are views showing the structure of a temporary substrate according to an embodiment of the present invention, and FIG. 15 is a view showing a self-assembly process using the temporary substrate according to FIG. 14D.

The temporary substrate 2000 may be a substrate on which the semiconductor light emitting devices 1100 formed on the growth substrate 1000 before self-assembly are transferred by pressure. The semiconductor light emitting devices 1100 may be temporarily fixed to the sacrificial layer 2100 formed on one surface of the temporary substrate 2000, and the sacrificial layer 2100 may be etched in a fluid in which self-assembly proceeds, so that the semiconductor light emitting device The field 1100 may be separated from the temporary substrate 2000.

That is, the temporary substrate 2000 may necessarily include the sacrificial layer 2100 for self-assembly according to an embodiment of the present invention, and the sacrificial layer 2100 has a bonding force to fix the semiconductor light emitting devices 1100. While having, it may be formed of a polymer material that can be etched in a fluid.

For example, the sacrificial layer 2100 is propylene-butene (butylene) copolymers, PVC cement, solvent type acrylic adhesives, solvent type soluble It may be a solvent-type adhesive such as polyimide (solvent soluble polyimide).

In this case, as the fluid L, acetone or isopropyl alcohol (IPA) capable of etching the sacrificial layer 2100 may be used.

On the other hand, the sacrificial layer 2100 formed of the above-described material is etched entirely in the fluid, but it is also possible to configure only a partial region of the sacrificial layer 2100 to be selectively etched in the fluid.

To this end, the sacrificial layer 2100 may be formed of a photosensitive material, and exposure (projection type photolithography) may be performed on only a partial area. As shown in FIG. 14D, the sacrificial layer 2100 may include an exposed area 2100a and a non-exposed area 2100b through an exposure process, and the fluid L is a developer capable of etching only the exposed area 2100a. By doing so, the sacrificial layer 2100 may be selectively etched.

At this time, at least some of the semiconductor light emitting devices 1100 fixed to the temporary substrate 2000 are fixed to the exposure area 2100a, so that the exposure area 2100a is in the fluid L. As etched in, only some of the semiconductor light emitting devices 1100 may be selectively separated from the temporary substrate 2000.

As another embodiment for selective separation, the temporary substrate 2000 may include an auxiliary bonding layer 2300 formed of a photosensitive material under the sacrificial layer 2100 (FIG. 14C), and in this case, the sacrificial layer 2100 ) May be formed of any of the above-described solvent-type adhesive materials.

In this case, through the above-described exposure process, the auxiliary bonding layer 2300 may include an exposed area 2300a and a non-exposed area 2300b, and only the exposed area 2300a may be selectively etched by a developer.

When the auxiliary bonding layer 2300 is exposed to light, the bonding force between the sacrificial layer 2100 and the semiconductor light emitting devices 1100 may be maintained for a long time.

When the temporary substrate 2000 structure including the auxiliary bonding layer 2300 is used, an isolation process may be performed on a region of the sacrificial layer 2100 to which the semiconductor light emitting devices 1100 are not fixed before the exposure process. That is, the sacrificial layer 2100 may be etched in a region between the semiconductor light emitting devices 1100 to expose the auxiliary bonding layer 2300 formed under the sacrificial layer 2100.

In addition, in order to remove the partial sacrificial layer 2100 remaining on one surface of the semiconductor light emitting devices 1100 after self-assembly, a process of replacing the fluid L with acetone or isopropyl alcohol in a developer may be performed.

Meanwhile, the temporary substrate 2000 may include a third assembly electrode 2200 for forming an electric field under the sacrificial layer 2100 according to the type of the acceptor substrate (FIG. 14B).

The third assembly electrode 2200 may cooperate with the assembly electrode formed on the acceptor substrate when power is applied to form an electric field for moving the semiconductor light emitting devices. In this case, the power applied to form the electric field may be a voltage.

In addition, the third assembly electrode 2200 may be formed of a transparent conductive material to align the temporary substrate 2000 so that the semiconductor light emitting devices 1100 formed on the temporary substrate 2000 face cells formed on the acceptor substrate. have.

The temporary substrate 2000 including the third assembly electrode 2200 may be used when the acceptor substrate is the wiring substrate 3000, which will be described later.

11 is a diagram illustrating an arrangement of sub-pixels and pixels on an acceptor substrate according to an exemplary embodiment of the present invention.

According to the present invention, the acceptor substrate may be made of only semiconductor light emitting devices 1100 emitting the same color, but preferably, semiconductor light emitting devices 1100 emitting two or more different colors may be assembled. have.

Specifically, the semiconductor light emitting devices 1100 used for self-assembly of the present invention include a blue semiconductor light emitting device that emits blue light (hereinafter, referred to as a BLUE chip), a green semiconductor light emitting device that emits green light (hereinafter, a GREEN chip), and a red color. It may include a red semiconductor light emitting device (hereinafter, RED chip) emitting light.

The BLUE chip, the GREEN chip, and the RED chip may be grown on different growth substrates 1000, transferred to different temporary substrates 2000, and finally assembled on the acceptor substrate through the above-described self-assembly method. .

For example, sub-pixels may be assembled in a matrix-like array on the acceptor substrate, and a unit pixel may be composed of four adjacent sub-pixels (2×2, RGBR) as shown in FIG. 11. Alternatively, the unit pixel may be composed of three sub-pixels (RGB).

In the self-assembly according to the present invention, the wiring board 3000 or the assembly board 4000 may be used as the acceptor substrate. Hereinafter, the semiconductor light emitting devices 1100 are manufactured as a pre-process of self-assembly, and the temporary board 2000 After explaining the process of fixing on the substrate, each case in which the wiring board 3000 and the assembly board 4000 are used as acceptor substrates will be described.

17 is a diagram illustrating a process from a manufacturing step of a semiconductor light emitting device to a transfer step to a temporary substrate as a pre-process of the self-assembly process according to an embodiment of the present invention.

The pre-process of self-assembly according to FIG. 17 can be equally applied regardless of the type of the acceptor substrate.

First, a step of growing a plurality of semiconductor layers constituting the semiconductor light emitting device 1100 on the growth substrate 1000 is performed. The BLUE chip and the GREEN chip can be grown by the nitride-based semiconductor growth method, and the RED chip can be by the phosphide-based semiconductor growth method.

Specifically, in the case of a BLUE chip and a GREEN chip, a first conductivity type semiconductor layer (hereinafter, n-type semiconductor layer) 1110, an active layer 1120, and a second conductivity type semiconductor layer (hereinafter, referred to as , p-type semiconductor layers) 1130 are sequentially stacked (FIG. 17A), and then a second conductivity-type electrode layer (hereinafter, p-type electrode layer) 1140 for forming an ohmic contact is deposited (FIG. 17B).

In the case of the RED chip, an n-type semiconductor layer 1110, an active layer 1120, and a p-type semiconductor layer 1130 may be sequentially stacked on the GaAs growth substrate 1000, and a p-type electrode layer 1140 may be deposited.

For example, the p-type electrode layer 1140 may be a transparent electrode layer such as indium tin oxide (ITO) or a metal electrode layer. In the case of a transparent electrode layer, it may be manufactured through sputtering and etching processes, and in the case of a metal electrode layer, it may be manufactured through E-beam deposition and lift-off process.

Next, a current injection region is formed on the p-type semiconductor layer 1130 through photolithography patterning and etching processes (FIG. 17C). There are a method of etching only a part of the surface of the p-type semiconductor layer 1130 or a method of etching only a part of the active layer 1120 so that the side of the active layer 1120 is not exposed as much as possible, and a method of etching so that a part of the n-type semiconductor layer 1110 is exposed. . The process of forming the current injection region is to prepare for a decrease in luminous efficiency due to a surface non-emission recombination phenomenon, and the step may be omitted.

Next, a passivation layer 1160 may be formed on the surface of the p-type semiconductor layer 1130 in which the current injection region is formed (FIG. 17D). The passivation layer 1160 may be formed by depositing an insulating film made _{of SiO 2} or SiN _x. The step of forming the passivation layer 1160 may be included or omitted depending on whether power is applied to the temporary substrate 2000 in the subsequent self-assembly process.

Thereafter, the growth substrate 1000 on which the plurality of semiconductor layers and passivation layers 1160 are formed and the temporary substrate 2000 on which the third assembly electrode 2200 and the sacrificial layer 2100 are deposited are bonded (FIG. 17E). . Specifically, the passivation layer 1160 of the growth substrate 1000 and the sacrificial layer 2100 of the temporary substrate 2000 may be bonded to come into contact with each other.

At this time, the third assembly electrode 2200 formed on the temporary substrate 2000 must be optically aligned so that the semiconductor light emitting device 1100 and the cells of the acceptor substrate face each other, so that it is made of a transparent conductive material (for example, ITO). Can be formed.

In addition, the sacrificial layer 2100 may be formed of a polymer material that can be easily etched by a fluid of a specific component while having a relatively strong bonding force at about 100°C (glass transition temperature, T _{g) where bonding is performed.} .

Next, the growth substrate 1000 is separated through a laser lift-off (LLO) or chemical lift-off (CLO) method (FIG. 17F), and the n-type semiconductor exposed to the surface as the growth substrate 1000 is separated. A process of thinning the thickness of the n-type semiconductor layer 1110 (approximately 5 to 10 μm in thickness) by etching the entire surface of the layer 1110 is performed (FIG. 17G).

Thereafter, after depositing a transparent conductor such as ITO on the n-type semiconductor layer 1110, patterning is performed so that the n-type electrode layer 1150 for ohmic contact is positioned at a position coincident with the current injection region (FIG. 17H), The process of manufacturing the semiconductor light emitting device 1100 may be completed by isolation etching (FIG. 17I), and a self-assembly process to be described later may be performed in this state.

12A to 12C are views showing a self-assembly process according to an embodiment (wiring substrate) of the present invention, and FIGS. 13A to 13C are views showing a self-assembly process according to another embodiment (assembly substrate) of the present invention. And FIG. 16 is a view showing an assembly electrode formed on an assembly substrate according to an embodiment of the present invention.

First, a case of using the wiring board 3000 as an acceptor substrate according to an embodiment of the present invention will be described.

The wiring substrate 3000 is a substrate on which the driving electrodes 3100 for driving the semiconductor light emitting devices 1100 are formed, and may be a substrate used as a final display panel.

Referring to FIGS. 12A to 12C, when the acceptor substrate is the wiring substrate 3000, power may be simultaneously applied to the temporary substrate 2000 and the wiring substrate 3000 so that an electric field is formed in a vertical direction. For example, the applied power may be a voltage, and voltages of different polarities may be applied to the temporary substrate 2000 and the wiring substrate 3000.

Accordingly, both the temporary substrate 2000 and the wiring substrate 3000 may include assembly electrodes for forming an electric field. For example, the temporary substrate 2000 including the third assembly electrode 2200 may be used as the temporary substrate 2000 (FIG. 14B), and the wiring substrate 3000 may be a first assembly electrode or a second assembly electrode. It may include. Alternatively, the driving electrode 3100 formed on the wiring board 3000 may function as a first assembly electrode or a second assembly electrode.

Here, the first assembly electrode and the second assembly electrode may be classified according to the polarity of the applied voltage. For example, a voltage of + polarity is applied to the first assembly electrode and a voltage of-polarity is applied to the second assembly electrode. Can be authorized.

When the acceptor substrate is the wiring board 3000, power is simultaneously applied to the third assembly electrode 2200 of the temporary board 2000 and the driving electrode 3100 of the wiring board 3000 to provide the temporary board 2000 and wiring. An electric field may be formed in the space between the substrates 3000 in a vertical direction, and the semiconductor light emitting devices 1100 fixed to the temporary substrate 2000 are separated from the sacrificial layer 2100, and thus the wiring board (3000) can be settled.

Meanwhile, in order to assemble all of the RED chip, the GREEN chip, and the BLUE chip on the wiring board 3000 as shown in FIGS. 12A to 12C, assembling the RED chip, assembling the GREEN chip, and assembling the BLUE chip are Each can be performed.

The order of each step can be arbitrarily changed, and in this specification, assembling in the order of RED chip-GREEN chip-BLUE chip will be described as an example.

First, self-assembly is performed using the temporary board 2000 and the wiring board 3000 on which the RED chips are formed at predetermined intervals, and then the temporary board 2000 and the wiring board 3000 on which the GREEN chips and the BLUE chips are formed in the same manner. ) Can be used for self-assembly. In this case, after the chips formed on the temporary substrate 2000 are aligned to face the cells 3200 to be mounted on the wiring board 3000, self-assembly may be performed.

In particular, GREEN chips may be arranged to face cells in which RED chips are not seated, and BLUE chips may be arranged to face cells in which RED chips and GREEN chips are not seated.

Meanwhile, when the transfer of the semiconductor light emitting devices 1100 fixed to one temporary substrate 2000 is completed, a step of discharging the fluid L to the acceptor substrate may be performed.

For example, when all the RED chips fixed to the temporary substrate 2000 are transferred to the wiring board 3000 as shown in FIG. 12A, the fluid L is discharged to the lower portion of the wiring board 3000, and A new fluid L may be re-injected, and when the step of transferring the GREEN chips as shown in FIG. 12B is completed, the fluid L may be discharged again and a new fluid L for assembling BLUE chips may be introduced.

In this case, the fixing force of the semiconductor light emitting devices 1100 assembled on the acceptor substrate may be improved by the adhesive component of the sacrificial layer 2100 dissolved in the fluid L.

18 is a view showing a post-process of the self-assembly process according to an embodiment of the present invention.

According to an embodiment of the present invention, a part of the driving electrode 3100 is exposed on the bottom surface of the cells 3200 formed on the wiring board 3000 to be mounted on the cell 3200 by self-assembly. ) May be electrically connected, and a part of the driving electrode 3100 may be a metal solder.

Specifically, after self-assembly is completed, the fluid L is discharged while an electric field is applied, and then heat and pressure are applied to bond the n-type electrode layer 1150 and the driving electrode 3100 of the semiconductor light emitting device 1100. Can be applied (Fig. 18A). In this case, the n-type electrode layer 1150 need not necessarily be a transparent electrode layer.

Subsequently, a passivation layer 3300 is formed on the wiring board 3000 and a planarization layer 3400 is formed to cover the passivation layer 3300 while filling the gap between subpixels, and then connected to the p-type electrode layer 1140. An AM type transparent driving electrode 3500 may be formed (FIGS. 18B to 18D ).

Next, a case where the assembly substrate 4000 is used as an acceptor substrate according to another embodiment of the present invention will be described.

The assembly substrate 4000 may be a substrate used to temporarily accommodate the semiconductor light emitting devices 1100 during self-assembly. Accordingly, the step of transferring the wiring board 3000 may be further performed as a post-process of self-assembly.

13A to 13C, when the acceptor substrate is the assembly substrate 4000, power is applied to the assembly substrate 4000 so that an electric field may be formed near the assembly substrate 4000 in a horizontal direction. For example, the applied power may be a voltage, and the assembly substrate 4000 may include a first assembly electrode 4100 and a second assembly electrode 4200 to which voltages of different polarities are applied.

The first assembly electrode 4100 and the second assembly electrode 4200 may be formed to be parallel to each other, and the first assembly electrode 4100 and the second assembly electrode 4200 may be alternately disposed. At this time, the cells 4300 on which the semiconductor light emitting devices 1100 are mounted overlap with the first assembly electrode 4100 and the second assembly electrode 4200, so that an electric field is formed inside the cell 4300 when power is applied. I can.

The semiconductor light emitting devices 1100 fixed to the temporary substrate 2000 may be seated on the assembly substrate 4000 by dielectrophoresis as the sacrificial layer 2100 is separated, and the assembly process is a wiring substrate using an acceptor substrate. Since it is the same as the case of using (3000), a detailed description will be omitted.

Meanwhile, in the process of discharging the fluid L to the acceptor substrate and the assembly substrate 4000 in this embodiment after self-assembly of one temporary substrate 2000 is completed as described above, it is dissolved in the fluid L. The adhesive component of the sacrificial layer 2100 may improve fixing power of the semiconductor light emitting devices 1100 to the assembly substrate 4000. Accordingly, in the process of transferring the semiconductor light emitting devices 1100 seated on the assembly substrate 4000 to the wiring board 3000, the semiconductor light emitting devices 1100 can be prevented from being separated from the surface of the assembly substrate 4000. I can.

Alternatively, if the acceptor substrate is the assembly substrate 4000, the step of applying the adhesive material 4400 to the assembly substrate 4000 after the transfer of the semiconductor light emitting devices 1100 fixed to the temporary substrate 2000 is completed. It can be optionally included. The fixing force of the semiconductor light emitting devices 1100 to the surface of the assembly substrate 4000 may be improved by the applied adhesive material 4400.

19 is a view showing a post-process of a self-assembly process according to another embodiment of the present invention.

According to another embodiment of the present invention, the semiconductor light emitting devices 1100 are temporarily seated on the assembly substrate 400, and thereafter, a step of transferring from the assembly substrate 4000 to the wiring substrate 3000 according to FIG. 18 is performed. Can be.

Referring to FIG. 19, a process of applying an adhesive material 4400 may be preceded in order to prevent separation of the semiconductor light emitting devices 1100 mounted on the assembly substrate 400, whereby the semiconductor light emitting devices 1100 Silver can be stably transferred to the wiring board 3000. The semiconductor light emitting devices 1100 seated on the assembly substrate 4000 may be transferred to the wiring board 3000 by pressing, and after being transferred to the wiring board 3000, the same post-process as shown in FIG. 18 may be performed.

However, in this embodiment, the semiconductor light emitting device 1100 is mounted on the wiring board 3000 through the assembly board 4000, and the semiconductor light emitting device 1100 connected to the driving electrode 3100 of the wiring board 3000 The electrode layer of may be a p-type electrode layer 1140.

As described above, in the method of manufacturing a display device according to an embodiment of the present invention, since the semiconductor light emitting devices 1100 formed on the temporary substrate 200 are transferred to the acceptor substrate while maintaining the gap, the temporary substrate 2000 ) And the acceptor substrate are aligned to allow the specific semiconductor light emitting device 1100 to be seated in a cell at a specific location.

In addition, the self-assembly of the semiconductor light emitting devices 1100 formed on the temporary substrate 2000 can be carried out at the same time, thereby improving the efficiency of the process, and minimizing the moving distance of the semiconductor light emitting devices 1100 to minimize the movement distance of the semiconductor light emitting devices 1100. ) Has the effect of preparing for loss and damage.

The above-described present invention is not limited to the configuration and method of the embodiments described above, and the embodiments may be configured by selectively combining all or part of each of the embodiments so that various modifications may be made.

1000: growth substrate
1100: semiconductor light emitting device
2000: temporary substrate
2100: sacrificial layer
2100a: exposure area
2100b: non-exposed area
2200: third assembly electrode
2300: auxiliary bonding layer
3000: wiring board
4000: assembly board
4100: first assembly electrode
4200: second assembly electrode

Claims (11)

Transferring the semiconductor light emitting devices formed on the growth substrate to the temporary substrate by bonding a growth substrate on which semiconductor light emitting devices are formed at predetermined intervals and a temporary substrate on which a sacrificial layer etched in a fluid is formed;
Introducing into a fluid an acceptor substrate in which cells on which the semiconductor light emitting devices are mounted are formed at predetermined intervals;
Aligning the temporary substrate in the fluid so that the sacrificial layer faces the acceptor substrate;
Applying power to at least one of the temporary substrate and the acceptor substrate to form an electric field for moving the semiconductor light emitting devices; And
And seating the semiconductor light emitting devices separated from the temporary substrate on the cells formed on the acceptor substrate,
The semiconductor light emitting devices,
A method of manufacturing a display device, characterized in that it is mounted on the acceptor substrate while maintaining the same distance as the distance formed on the growth substrate. The method of claim 1,
At least the semiconductor light emitting devices fixed to the temporary substrate are aligned to face the cells formed on the acceptor substrate. The method of claim 1,
The acceptor substrate includes at least one of a first assembly electrode and a second assembly electrode that forms an electric field when power is applied,
An assembly substrate temporarily accommodating the semiconductor light emitting devices, or a wiring board having driving electrodes for driving the semiconductor light emitting devices formed thereon. The method of claim 3,
The temporary substrate includes a third assembly electrode that forms an electric field for moving the semiconductor light emitting devices in cooperation with the first assembly electrode or the second assembly electrode of the acceptor substrate when power is applied,
The third assembly electrode is a method of manufacturing a display device, characterized in that formed of a transparent conductive material. The method of claim 3,
The method of manufacturing a display device, characterized in that the first assembly electrode and the second assembly electrode are formed to be parallel to each other. The method of claim 3,
The driving electrode includes a metal solder electrically connected to the semiconductor light emitting devices,
The wiring board is characterized in that at least a part of the metal solder is exposed on a bottom surface of the cell. The method of claim 1,
The temporary substrate, a method of manufacturing a display device, comprising an auxiliary bonding layer formed of a photosensitive material under the sacrificial layer. The method of claim 1,
The sacrificial layer is formed of a photosensitive material and includes an exposed region etched in the fluid and a non-exposed region not etched in the fluid,
At least some of the semiconductor light emitting devices, characterized in that fixed to the exposure area, a method of manufacturing a display device. The method of claim 1,
And discharging the fluid to a side on which the acceptor substrate is disposed after the transfer of the semiconductor light emitting devices fixed to the temporary substrate is completed. The method of claim 3,
When the acceptor substrate is the assembly substrate, after the transfer of the semiconductor light emitting devices fixed to the temporary substrate is completed, the step of applying an adhesive material to the assembly substrate is selectively included. Manufacturing method. The method of claim 1,
The semiconductor light emitting devices include a blue semiconductor light emitting device emitting blue light, a green semiconductor light emitting device emitting green light, and a red semiconductor light emitting device emitting red light.

Images