KR101899651B1 - Micro-LED Array and Method of forming the same - Google Patents

Abstract

A structure of a micro element array and a method of forming a micro element array are disclosed. The micro-device is a micro-sized light-emitting diode that can be used in a display. A magnetic layer is formed on the micro element mounted on the transfer substrate, and the micro element can be selectively transferred by applying a magnetic field to the formed magnetization layer.

Description

[0001] The present invention relates to a micro-LED array and a method of forming the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a micro element array and a method of forming the micro element array, and more particularly, to a micro element array precisely arranged by avoiding damage of a micro element as much as possible and a method of forming the same.

BACKGROUND ART [0002] Recently, a technology for separating a light emitting diode having a micrometer size from a growth substrate and transferring it to a receiving substrate is under development. Particularly, the micro devices transferred to the receiving substrate are used for packaging in an integrated state or being transferred to another substrate. It is required that a plurality of devices are transferred and transported rather than a single device for transferring micro devices.

In order to secure the efficiency and mass productivity of a display using a micro device, transferring or transferring individual devices individually is an important factor for increasing the total process time and increasing the defect rate. In addition, the micro devices separated individually during transfer and transfer may be damaged, and the problem of degradation of transfer and transfer accuracy may result in failure to realize a desired display.

As a technique for transferring or transferring a micro device, an elastic polymer such as poly (dimethylsiloxane) (PDMS) is used as a stamp. A stamp composed of an elastomer is tightly coupled to the van der Waals forces with the microelements formed on the growth substrate and is used to pick up and transport the microelements. When the elastomer is used as a stamp, there arises a problem that the adhesion strength of the stamp decreases in the course of repetitive transfer and transfer. In addition, oxygen plasma or ozone treatment must be continuously performed in order to restore the adhesive strength of the stamp, which is a cause of lowering the productivity.

In addition, as a technique for picking up and transporting the micro devices, a method using static electricity can be used. US Patent Publication No. 2013-0128585 discloses a method of forming a micro element array through a transfer head using static electricity. In the present invention, the transfer head is connected to a power source for generating static electricity, and selectively picks up and transfers the micro elements formed on the transfer substrate using static electricity. Further, in order to apply the static electricity, the transfer head or the micro device must be coated with a thin dielectric film, which causes physical damage or chemical damage in repeated pickup, transfer, and bonding processes. Particularly, when high static electricity is applied, electrostatic breakdown phenomenon occurs and static electricity can not be applied through the transfer head.

Therefore, a technique for forming a micro-device array more effectively and transferring it will still be required.

A first object of the present invention is to provide a micro element array formed through effective transfer.

According to a second aspect of the present invention, there is provided a method of forming a micro element array for achieving the first technical object.

According to an aspect of the present invention, there is provided a display device comprising: a display substrate; And a plurality of micro elements formed on the receiving substrate, wherein each of the micro elements comprises: a second electrode layer formed on the receiving substrate; A second semiconductor layer formed on the second electrode layer; An active layer formed on the second semiconductor layer to form light; A first semiconductor layer formed on the active layer and having a conductivity type complementary to the second semiconductor layer; And a magnetization layer formed on the first semiconductor layer and having a ferromagnetic material magnetized in a specific direction.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a first semiconductor layer, an active layer, and a second semiconductor layer on a substrate for growth; Removing a portion of the first semiconductor layer, the active layer, and the second semiconductor layer to expose a portion of the substrate for growth and forming individualized micro devices; Transferring the individualized micro elements onto a transfer substrate; Forming a magnetic layer on the micro element on the transfer substrate; And introducing a transfer head having a magnetic field in a specific direction into the magnetization layer to move the micro device on a display receiving substrate.

According to the present invention described above, the transfer of the micro-element, which is an individual light-emitting diode having a micro-size, is carried out through magnetic force. The micro elements are transferred onto the transfer substrate in an individualized state, and the micro elements arranged on the transfer substrate are transferred to the receiving substrate through magnetic force.

In the case of transporting a micro device through a conventional vacuum suction method, it is difficult to control the degree of vacuum. In case of transferring a micro device by using static electricity, the characteristics of the micro device may be deteriorated due to excessive static electricity. In the invention, micro devices are transferred using magnetic force which does not affect the characteristics of the device. Therefore, it becomes possible to realize a display using micro devices more stably.

1 is a cross-sectional view illustrating a micro element array according to a first embodiment of the present invention.
FIGS. 2 to 8 are cross-sectional views illustrating a method of forming the micro element array of FIG. 1 according to a preferred embodiment of the present invention.
8 to 12 are cross-sectional views illustrating a method of forming the micro element array of FIG. 1 according to a second embodiment of the present invention.
13 is a cross-sectional view showing an example of a transfer head used in the first embodiment and the second embodiment of the present invention.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First Embodiment

1 is a cross-sectional view illustrating a micro element array according to a first embodiment of the present invention.

Referring to FIG. 1, each of the micro elements 200 is provided on a receiving substrate 400 in a state where the micro elements 200 are separated from each other. The microns 200 have a second electrode layer 150, a second semiconductor layer 140, an active layer 130, a first semiconductor layer 120, and a magnetization layer 170 from a receiving substrate 400.

The receiving substrate 400 may be any material that can be used for display or illumination. In particular, the receiving substrate 400 may include a transistor by a separate lamination structure, or may include an integrated circuit or metal wiring. In addition, the receiving substrate 400 may be a substrate on which a plurality of individual substrates are combined or bonded.

Examples of the material that can constitute the receiving substrate 400 include ceramics such as gallium nitride, glass, sapphire, quartz, and silicon carbide; or ceramics such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, Or an organic material such as polyimide or a flexible material substrate. In addition, the receiving substrate 400 may have electrical thermal conductivity or have electrical thermal insulation depending on the use example.

A second electrode layer 150 is formed on the receiving substrate 400. The second electrode layer 150 may be formed of ITO, which is a transparent conductive material. When the second electrode layer 150 is made of a transparent conductive material, the second electrode layer 150 functions as a current diffusion layer. In addition, the second electrode layer 150 may have a stacked structure of a current diffusion layer and a metal electrode layer. That is, the metal electrode layer and the current diffusion layer may be sequentially formed on the receiving substrate 400. For example, the metal electrode layer may be provided as a patterned metal pattern.

A second semiconductor layer 140 is formed on the second electrode layer 150. The composition and material of the second semiconductor layer 140 vary depending on the composition and material of the active layer 130 formed on the second semiconductor layer 140. For example, when the active layer 130 forms blue or green light, the second semiconductor layer 140 may have a GaN or InGaN material. In addition, when the active layer 130 forms red light, the second semiconductor layer 140 may have an InGaP material. It is preferable that the second semiconductor layer has a p-type conductivity type.

The active layer 130 is formed on the second semiconductor layer 140. The active layer 130 preferably has a multiple quantum well structure. For example, the active layer 130 may have a well layer of InGaN and a barrier layer of GaN, or alternatively, a well layer and a barrier layer may be formed of InGaNs having a difference in In fraction. In addition, the active layer may have a multiple quantum well structure in which AlInGaP is a well layer and InGaP is a barrier layer.

A first semiconductor layer 120 is formed on the active layer 130. The first semiconductor layer 120 is formed of the same base material as the second semiconductor layer 140, but has a different dopant and a complementary conductive type. Accordingly, if the first semiconductor layer 120 has an n-type conductivity, the second semiconductor layer 140 has a p-type conductivity.

A magnetization layer 170 is formed on the first semiconductor layer 120. The magnetization layer 170 is preferably made of a magnetic material magnetized in a specific direction. The magnetic material may be composed of a ferromagnetic material and may be composed of Fe, Ni, Co, Cr, Cu, Si, Mn, W, C, Al, Pt, Sm, Nd, B, P, Bi, Sb, Y, Gd, Dy , Eu, or an alloy thereof. In addition, the magnetization layer 170 may be provided in a patterned state in a specific form, and a first electrode layer may be formed in a spaced space between the patterned magnetization layers 170. In addition, if the magnetization layer 170 is not patterned in a specific shape, the first electrode layer may be formed on the magnetization layer 170.

2 to 7 are cross-sectional views illustrating a method of forming the micro element array of FIG. 1 according to a preferred embodiment of the present invention.

Referring to FIG. 2, a buffer layer 110, a first semiconductor layer 120, an active layer 130, a second semiconductor layer 140, a second electrode layer 150, and a bonding layer (not shown) 160 are sequentially formed.

The substrate 100 for growth may have a material of sapphire, silicon, silicon carbide, gallium nitride, gallium arsenide, gallium phosphorus, or zinc oxide. The substrate 100 for growth may be grown on the substrate 100 and may be selected as a material suitable for growth depending on the type of the film to be formed.

For example, when the buffer layer 110 or the first semiconductor layer 120 has a GaN-based crystal structure, the growth substrate 100 may be selected as sapphire. In addition, when the buffer layer 110 or the first semiconductor layer 120 has an InGaP-based crystal structure, the growth substrate 100 may be selected as gallium arsenide.

A buffer layer 110 is formed on the substrate 100 for growth. The buffer layer 110 is provided for eliminating crystal defects due to mismatch of lattice constants between the film to be formed later and the substrate 100 for growth. The buffer layer 110 may include silicon, silicon carbide, zinc oxide, gallium nitride, gallium arsenide, or aluminum nitride. The buffer layer 110 may be formed by metal-organic chemical vapor deposition, molecular beam epitaxy, hydride vapor phase epitaxy, sputtering, or the like .

In addition, the forming process of the buffer layer 110 may be omitted according to the embodiment.

A first semiconductor layer 120, an active layer 130, and a second semiconductor layer 140 are sequentially formed on the buffer layer 110.

The carriers formed in the first semiconductor layer 120 move to the active layer and recombine with the carriers formed in the second semiconductor layer 140. Whereby a light emission operation of a specific color is performed. The first semiconductor layer 120 may have a GaN or InGaP material. The step of forming the first semiconductor layer 120 is preferably the same as the step of forming the buffer layer.

The active layer 130 is formed on the first semiconductor layer 120. The active layer 130 preferably has a multiple quantum well structure. Therefore, the well layer and the barrier layer are alternately formed, and the band gap of the well layer is set to be lower than the first semiconductor layer 120 or the second semiconductor layer 140. In particular, when the active layer 130 forms blue or green light, the well layer may be composed of InGaN, and the wavelength of the light formed through the adjustment of the fraction of In is adjusted. When the active layer 130 forms red light, the well layer may be composed of AlInGaP, and the wavelength of light formed through the adjustment of the Al fraction may be adjusted.

A second semiconductor layer 140 is formed on the active layer 130. The second semiconductor layer 140 has the same material and crystal structure as the first semiconductor layer 120 but has a conductive type complementary to the first semiconductor layer 120.

A second electrode layer 150 and a bonding layer 160 are sequentially formed on the second semiconductor layer 140. The second electrode layer 150 may have a transparent conductive ITO. The transparent conductor can be used as a current diffusion layer.

The second electrode layer may be a Ni or Ag-based conductor, and may be applied to an electric field applied to the second semiconductor layer and a conductor capable of performing an ohmic contact with the outside.

In addition, a separate metal electrode layer may be provided on the current diffusion layer, and the metal electrode layer may be provided in a patterned form. The metal electrode layer may be formed of Ni, Pd, Rh, Ti, Cr, Al, Ag, Au, or the like to achieve ohmic contact in electrical contact with a metal wiring to be formed later. Ge, Si, In, Ga, Sb, W, Mo, Pt, Co, Sn or Ta.

The bonding layer 160 may be made of a metal material and may be formed of a metal such as Ni, Pd, Rh, Ti, Cr, Al, Ag, Au, Ge, Si, In, Ga, Sb, , Sn, or Ta.

Referring to FIG. 3, the etching process for the structure of FIG. 2 is performed. Through the etching process, the light emitting diodes are individualized into the respective micro devices 200. The etching proceeds until a part of the surface of the growth substrate 100 is exposed. Thus, individualized microdevices 200 are formed on the substrate 100 for growth.

In addition, the formation of the second electrode layer 150 and the bonding layer 160 in the process of FIG. 2 may be omitted. That is, the second semiconductor layer 140 is formed in FIG. 2, and the separation process of the micro device 200 through the etching process is performed. The second electrode layer 150 and the bonding layer 160 may be sequentially formed through the deposition process for the separated micro-device 200. FIG.

Referring to FIG. 4, a bonding layer 160 of an individualized micro device 200 is bonded onto a transfer substrate 250. The transfer substrate 250 may be made of any material capable of achieving bonding with the bonding layer 160. For example, the transfer substrate 160 may be made of a metal material, and may have an oxide or nitride material. The bonding of the transfer substrate 250 is accomplished by fusion bonding of the bonding layer 160. [ In addition, a separate adhesive layer may be provided on the transfer substrate 250. By the introduction of the adhesive layer, bonding between the bonding layer and the transfer substrate 250 is further facilitated.

Then, a lift-off process is performed by irradiating a laser from the back surface of the substrate 100 for growth. The lift-off process is a process of separating the substrate 100 for growth from the individual microelements 200. That is, when the laser is concentrated on the buffer layer 110 or the first semiconductor layer 120, nitrogen gas is generated in the buffer layer 110 of GaN or the like, and the growth substrate 100 is separated by the gas pressure. If the substrate 100 for growth has a gallium arsenide material other than sapphire, the separation of the substrate 100 for growth may be performed by wet etching. Whereby the substrate 100 for growth is separated from the micro-device 200.

The micro element 200 is transferred onto the transfer substrate 250 and the buffer layer or the first semiconductor layer 120 of the micro element 200 is exposed. If the formation of the buffer layer is omitted in the manufacturing process of FIG. 2, the first semiconductor layer 120 may be exposed. Also, the removal process of the buffer layer of the micro element 200 on the transfer substrate 250 may be performed according to the embodiment.

Referring to FIG. 5, a magnetization layer 170 is formed on a first semiconductor layer 120 of a micro-device 200. The formation of the magnetization layer 170 may be performed by various methods such as sputtering deposition, vacuum deposition, dip coating, spray coating, molecular vapor deposition or plating. The magnetization layer 170 may be formed of at least one of Fe, Ni, Co, Cr, Cu, Si, Mn, O, W, C, Al, Pt, Sm, Nd, B, P, Bi, Sb, Y, Gd, Eu. ≪ / RTI > After the magnetization layer 170 is formed, a magnetization process is performed. The magnetization process is achieved by applying a magnetic field from the outside to set the magnetization direction of the magnetization layer 170 to be constant. For example, when the magnetization layer 170 has Supermalloy (16Fe: 79Ni: 5Mo), a magnetic field having a coercivity of 0.0025 Oe or more is applied from the outside to magnetize the magnetization layer 170 in a predetermined direction. Thus, the magnetization layer 170 magnetized in a specific direction can be obtained.

In addition, a protective layer 180 may be formed on the magnetization layer 170. The protective layer 180 is provided to protect the transport head and the magnetization layer 170 in the process of transporting the micro device 200. It is to be understood that the protective layer 170 can be made of SiO2 or SiN, and there is substantially no limitation on the material.

Referring to FIG. 6, the transfer head 300 is introduced into the micro-device 200 in which the magnetization layer 170 is formed. The transfer head 300 has a structure of an electromagnet. That is, the direction of the magnetic field can be changed according to the direction of the current. Further, when the supply of the electric current is interrupted, no magnetic field is formed. So that the transfer head 300 can form a magnetic force between the magnetization layer 170 and the repulsive force. If the magnetization layers 170 of FIG. 6 form a magnetic field directed from the bottom to the top of the transfer substrate 250, the transfer head 300, which contacts the specific micro element 200, When a magnetic field is formed, attraction is exerted between the specific micro element 200 and the transporting head.

Heat is applied from the lower portion of the transfer substrate 250 to the transfer head 300 and the micro element 200 to which the attraction is applied. The transfer substrate 250 and the micro element 200 are separated from each other due to the applied heat. That is, the bonding layer 160 is melted due to the heat applied from the back surface of the transfer substrate 250, and when a force is applied from the transfer head 300 in a molten state, the corresponding micro element 200 is transferred from the transfer substrate 250 Separated. A part of the bonding layer 160 may remain on the second electrode layer 150 in the process of separating the micro device 200. [

Referring to FIG. 7, a micro device 200 that is moved through a transfer head is mounted on a receiving substrate 400. The receiving substrate 400 may be any material that can be used for display or illumination. In particular, the receiving substrate 400 may include a transistor by a separate lamination structure, or may include an integrated circuit or metal wiring. In addition, the receiving substrate 400 may be a substrate on which a plurality of individual substrates are combined and bonded.

The microelectronic device 200 mounted on the receiving substrate 400 includes the second electrode layer 150, the second semiconductor layer 140, the active layer 130, the first semiconductor layer 120, And a magnetization layer 170 are sequentially formed. A plurality of light emitting diodes having a diameter of a few microamperes to several tens of microamperes can be formed on the receiving substrate 400. In addition, the micro elements 200 mounted on the receiving substrate 400 form light of a different color to the adjacent micro elements. Thus, a display pixel can be realized.

Second Embodiment

8 to 12 are cross-sectional views illustrating a method of forming the micro element array of FIG. 1 according to a second embodiment of the present invention.

8, a buffer layer 510, a first semiconductor layer 520, an active layer 530, a second semiconductor layer 540, and a second electrode layer 550 are sequentially formed on a substrate 500 for growth do.

The material of each film quality is the same as that described in Fig. 2 of the first embodiment.

A second electrode layer 550 is formed on the second semiconductor layer 540. The second electrode layer 550 may include a current diffusion layer in which ITO is used and a metal electrode layer that performs ohmic bonding. The metal electrode layer that performs the ohmic contact includes Ni, Pd, Rh, Ti, Cr, Al, Ag, Au, Ge, Si, In, Ga, Sb, W, Mo, Pt, Co, Sn or Ta. Also, the second electrode layer 550 may be provided in a patterned form.

Referring to FIG. 9, the microelectronic devices 600 (600) are formed by selectively etching the second electrode layer 550, the second semiconductor layer 540, the active layer 530, the first semiconductor layer 520 and the buffer layer 510 ). This is performed through etching, and light emitting diodes having several micro to several tens of micro-sizes are individually produced through etching. In addition, the surface of the substrate 500 for growth is exposed through the spacing space between the individualized micro elements 600.

The individualization of the microdevice 600 can also be achieved by other methods. For example, the second semiconductor layer 540 is formed in FIG. 8, and the second electrode layer 550 is not formed successively. In addition, in the step of FIG. 9, the microelectronic device 600 can be individualized through selective etching of the second semiconductor layer 540 and the subsequent films. The second electrode layer 550 may be formed on the second semiconductor layer 540 of each of the individually separated micro elements 600 through a conventional deposition method.

Referring to FIG. 10, a transfer substrate 650 is prepared. The transfer substrate 650 has a groove suitable for the size of the individual micro-device 600 formed in the above-described FIG. 9, and has a protrusion 660 defining a groove. The height of the protruding portion 660 is preferably set in a range from 1 [mu] m to 3 [mu] m, since the height of the conventional micro element is 1 [mu] m to 3 [mu] m and the width of the micro element is several um to several tens [mu] m. However, it is preferable that the height of the protrusion 660 is lower than the height of the micro device 600. This is because it is easy to transfer the micro device 600 in a subsequent process.

The individualized microelements 600 of FIG. 9 are introduced into the grooves of the transfer substrate 650. Then, the laser is irradiated to the back surface of the substrate 500 for growth, and the micro-elements 600 individually separated by the laser are separated from the substrate 500 for growth. If the substrate 500 for growth includes gallium arsenide, the micro devices 600 can be separated by wet etching.

10, the micro elements 600 are introduced into the grooves between the protrusions 660 formed on the transfer substrate 650. In addition, the first semiconductor layer 520 of the micro elements 600 introduced into the trench is exposed toward the outside. If the buffer layer 510 of FIG. 9 remains on the micro-device 600 by laser irradiation, the buffer layer 510 may be removed through a separate removal process, and the buffer layer 510 May remain on the first semiconductor layer 520.

10, a separate adhesive layer is not interposed between the microdevice 600 and the transfer substrate 650, and the microdevices 600 are aligned and fixed by grooves formed on the transfer substrate 650.

Referring to FIG. 11, a magnetization layer 560 is formed on the first semiconductor layer 520 of the micro-device 600. The magnetization layer 560 is formed by applying a photoresist to the protrusions 660 of the exposed transfer substrate 650 and then performing a conventional evaporation method such as sputtering and removing the formed photoresist pattern by a lift- . In addition, the magnetization layer 560 may be formed by various methods such as vacuum deposition, dip coating, spray coating, molecular vapor deposition, or plating. The magnetization layer 560 may be formed of Fe, Ni, Co, Cr, Cu, Si, Mn, O, W, C, Al, Pt, Sm, Nd, B, P, Bi, Sb, Y, Gd, Eu. ≪ / RTI > After the formation of the magnetization layer 560, a magnetization process is performed. The magnetization process is achieved by applying a magnetic field from the outside to set the magnetization direction of the magnetization layer 560 constant. For example, an external magnetic field is applied to the magnetization layer 560 to form the magnetization layer 560 into a ferromagnetic material, and magnetize the magnetization layer 560 in a predetermined direction. Thus, the magnetized layer 560 magnetized in a specific direction can be obtained.

Also, a protective layer 570 may be formed on the magnetization layer 560. The protective layer 570 is provided to protect the transport head and the magnetization layer 570 in the process of transporting the micro devices. It is to be understood that the protective layer 570 may be made of SiO2 or SiN, and there is substantially no limitation on the material.

12, a transfer head 700 is introduced into a micro device 600 having a magnetization layer 560 formed therein, and the transfer head 700 has an electromagnet structure. That is, the direction of the magnetic field changes according to the direction of the current, and when the supply of the current is interrupted, no magnetic field is generated. Thus, it is possible to generate attractive force that can be placed on a specific microelement 600 to transport a particular microelement 600.

12, since the micro element 600 is mounted on the groove of the transfer substrate 650 without a separate adhesive means, when a force due to a magnetic force is applied, the micro element 600 in contact with the transfer head 700 Can be easily separated from the transfer substrate 650. [

Subsequently, as shown in Fig. 7, the micro elements moved through the transfer head are mounted on the receiving substrate. Thus, a display using the light emitting diodes as individual pixels can be realized.

13 is a cross-sectional view showing an example of a transfer head used in the first embodiment and the second embodiment of the present invention.

Referring to FIG. 13, the transfer head has a housing 710, an inner coil 720, and a magnetic core 730.

The housing 710 is used to protect the internal structure from the outside and to achieve electrical insulation between the inner coil 720 and the external contact element. Therefore, there is no particular limitation as long as the material has insulating properties.

Further, an inner coil 720 is provided in the inner wall of the housing 710 in a patterned form. The inner coil 720 is provided inside the transfer head and is electrically connected to the external power supply V and the switching S. The inner coil 720 may be provided in a patterned form on the inner wall of the housing 710 and may be provided in a shape that surrounds the periphery of the magnetic core 730. However, if the magnetic core 730 has a structure capable of forming a magnetic field, it will not depart from the spirit of the present invention.

The external power supply V can change the direction of the magnetic field formed in the magnetic core 730 through changing the direction of the current. Whereby the detachment of the micro element in contact with the transfer head is achieved. Further, the external power supply V is connected to the switch S, and the current is transmitted to the inner coil 720 through the switch S.

However, it should be understood that the structure of the transfer head disclosed in FIG. 13 is an example of a structure for transferring micro-elements using magnetic force. Therefore, the micro-elements can be transferred through the use of a transfer head or the like having a different structure using a magnetic force, and this is not outside the scope of the present invention.

In the embodiments of the present invention, it is shown that one transfer head is provided, but this is merely to explain the transfer of at least one micro element. Therefore, the transporting head is composed of a plurality of transporting heads, and when necessary, a plurality of transporting heads can simultaneously transport a plurality of the Michael elements.

In the present invention, the microelectronic element, which is an individual light emitting diode having a micro size, is conveyed through a magnetic force. The micro elements are transferred onto the transfer substrate in an individualized state, and the micro elements arranged on the transfer substrate are transferred to the receiving substrate through magnetic force.

In the case of transporting a micro device through a conventional vacuum suction method, it is difficult to control the degree of vacuum. In case of transferring a micro device by using static electricity, the characteristics of the micro device may be degraded due to excessive static electricity. In the invention, micro devices are transferred using magnetic force which does not affect the characteristics of the device. Therefore, it becomes possible to realize a display using micro devices more stably.

100, 500: Growth substrate 120, 520: First semiconductor layer
130, 530: an active layer 140, 540: a second semiconductor layer
150, 550: second electrode layer 200, 600:
250, 650: transfer substrate 170, 560: magnetization layer
660: protrusion 400: receiving substrate

Claims (13)

delete delete delete delete delete Sequentially forming a first semiconductor layer, an active layer and a second semiconductor layer on a substrate for growth,
Removing a part of the first semiconductor layer, the active layer, and the second semiconductor layer to expose a part of the substrate for growth, thereby forming an individualized micro element completely separated from the adjacent first semiconductor layer, the active layer and the second semiconductor layer Forming step
Transferring the individualized micro devices onto a transfer substrate to expose the surface of the first semiconductor layer, wherein the first semiconductor layer is the uppermost layer;
Forming a magnetization layer completely shielding the exposed upper surface of the first semiconductor layer in the microdevices on the transfer substrate; and
And introducing a transfer head having a magnetic field in a specific direction into the magnetization layer to move the micro element on a receiving substrate for display. 7. The method of claim 6, further comprising forming a second electrode layer and a bonding layer on the second semiconductor layer prior to the step of forming the individualized microdevices. 8. The method of claim 7, wherein the step of transferring the individualized micro devices to the transfer substrate comprises:
Fusing the bonding layer on the transfer substrate; And
And separating the growth substrate from the individualized micro devices. ≪ RTI ID = 0.0 > 11. < / RTI > 9. The method of claim 8, wherein moving the microdevice on the receiving substrate comprises:
And fusing the fused bond layer to separate the micro element from the transfer substrate through the transfer head. 7. The method of claim 6, wherein forming the magnetization layer comprises:
Depositing the magnetization layer on the first semiconductor layer on the transfer substrate; And
And magnetizing the magnetization layer in a specific direction by applying a magnetic field in a specific direction to the magnetization layer. 11. The method of claim 10, further comprising forming a protective layer having an insulating property on the magnetic layer after forming the magnetization layer. 7. The method of claim 6, wherein the transfer substrate has a protrusion and a groove defined by the protrusion, and the individualized micro-device is introduced into the groove. 13. The method of claim 12, wherein the grooves are provided corresponding to the individualized microdevices, and the height of the protrusions defining the grooves is 1 um to 3 um.

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