KR20200001324A - Transfer head for micro led - Google Patents

Abstract

The present invention relates to a micro LED transfer head, which transfers a micro LED to a second substrate from a first substrate, and more specifically, to a micro LED transfer head, which allows uniform vacuum pressure to be formed on an adsorption surface adsorbing a micro LED, thereby improving transfer efficiency with respect to the micro LED.

Description

Micro LED transfer head {TRANSFER HEAD FOR MICRO LED}

The present invention relates to a micro LED transfer head for transferring the micro LED from the first substrate to the second substrate.

Currently, the display market is still the mainstream, while OLED is rapidly becoming the mainstream by replacing LCD. As display companies are participating in the OLED market rush, Micro LED (hereinafter referred to as “micro LED”) display is emerging as another next generation display. Whereas the core materials of LCD and OLED are liquid crystal and organic materials, micro LED display is a display that uses LED chip of 1 ~ 100 micrometer (μm) unit as light emitting material.

When Cree applied for a patent on "Micro-light Emitting Diode Arrays with Improved Light Extraction" in 1999 (Registration No. 0731673), the research and development has been published since the publication of the term micro LED. This is being done. The challenge to apply micro LEDs to displays requires the development of custom microchips based on flexible materials / devices for micro-LED devices, and the accuracy of transfer and display pixel electrodes of micrometer-sized LED chips. There is a need for technology for mounting.

In particular, in connection with the transfer for transferring the micro LED device to the display substrate, as the LED size is reduced to the unit of 1-100 micrometers (μm), it is not possible to use the existing pick & place equipment, There is a need for a transfer head technology that transfers more precisely. In relation to the transfer head technology, several structures as described below have been proposed, but each proposed technology has some disadvantages.

Luxvue of the United States has proposed a method for transferring a micro LED using an electrostatic head (Public Patent Publication No. 2014-0112486, hereinafter referred to as "prior invention 1"). The transfer principle of the present invention 1 is a principle of generating adhesion between the micro LED and the charging by applying a voltage to a head part made of silicon. This method may cause a problem of micro LED damage due to a charging phenomenon due to the voltage applied to the head during the electrostatic induction.

X-Celeprint Inc. of the United States proposed a method of transferring the micro LED on the wafer to the desired substrate (P) by applying the transfer head as an elastic polymer material (Patent Publication No. 2017-0019415, hereinafter referred to as 'prior invention'). 2 '). This method has no problems with LED damage compared to the electrostatic head method, but it can transfer micro LEDs stably when the transfer force of the elastic transfer head is larger than the adhesion force of the target substrate P in the transfer process. There is a disadvantage that a process is required. In addition, maintaining the adhesive strength of the elastomeric material is also a very important factor.

The Korean Institute of Optical Technology proposed a method for transferring micro LEDs using a cilia adhesive structure head (registered patent publication No. 1754528, hereinafter referred to as 'prior invention 3'). However, the preceding invention 3 has a disadvantage in that it is difficult to manufacture the adhesive structure of the cilia.

The Korea Institute of Machinery and Materials proposed a method of transferring micro LEDs by coating an adhesive on a roller (registered patent publication No. 1757404, hereinafter referred to as 'prior invention 4'). However, the present invention 4 requires the continuous use of the adhesive, and there is a disadvantage that the micro LED may be damaged when the roller is pressed.

Samsung Display applies a negative voltage to the first and second electrodes of the array substrate P while the array substrate P is in a solution to transfer the micro LEDs to the array substrate P by electrostatic induction. It is proposed (Patent Publication No. 10-2017-0026959, hereinafter referred to as 'prior invention 5'). However, the preceding invention 5 has a disadvantage in that a separate solution is required in that it is transferred to the array substrate P by immersing the micro LED in a solution and then a drying process is required.

LG Electronics has proposed a method of arranging a head holder between a plurality of pickup heads and a substrate P and deforming its shape by the movement of the plurality of pickup heads to provide freedom to the plurality of pickup heads. Publication No. 10-2017-0024906, hereinafter referred to as 'prior invention 6'). However, the present invention 6 is a method of transferring a micro LED by applying a bonding material having an adhesive force to the adhesive surface of the plurality of pickup heads, there is a disadvantage that a separate process for applying a bonding material to the pickup head is required.

In order to solve the problems of the preceding inventions, the above-mentioned disadvantages should be improved while adopting the basic principles adopted by the preceding inventions. These disadvantages are derived from the basic principles adopted by the preceding inventions. There are limits to improving the shortcomings. Accordingly, the applicant of the present invention is not only to improve the disadvantages of the prior art, but to propose a new method that has not been considered in the prior inventions at all.

Registered Patent Publication No. 0731673 (Patent Document 2) Publication No. 2014-0112486 Korean Laid-Open Patent Publication No. 2017-0019415 Registered Patent Publication No. 1754528 Registered Patent Publication No. 1757404 Patent Publication No. 10-2017-0026959 Patent Publication No. 10-2017-0024906

Accordingly, an object of the present invention is to provide a micro LED transfer head capable of uniformly forming a vacuum pressure to generate the adsorption force of the adsorption surface for adsorbing the micro LED to improve the transfer efficiency for the micro LED.

Micro LED transfer head according to an aspect of the present invention, the suction member for sucking the micro LED; A support member provided on an upper surface of the non-adsorption area of the suction member; And a communication member coupled to the support member at an upper portion of the support member and configured to communicate air between the areas 30 between the support members.

In addition, the communication member is characterized in that the groove crossing the support member is provided on the lower surface.

In addition, the communication member is characterized in that the porous member having pores.

In addition, the adsorption member is characterized in that the porous adsorption member having vertical pores.

In addition, the adsorption member is characterized in that the anodized film formed by anodizing the metal.

In addition, the communication member is characterized in that the suction hole is formed.

In addition, the upper portion of the communication member is characterized in that the vacuum chamber is coupled.

As described above, the micro LED transfer head according to the present invention allows the vacuum transfer area for generating the adsorption force for adsorbing the micro LED to be in air communication with each other so that a uniform vacuum pressure can be formed in the adsorption area. The LED can be transferred more efficiently.

1 is a view showing a micro LED to be transferred in the embodiments of the present invention.
2 is a view of a micro LED structure transferred to and mounted on a display substrate according to embodiments of the present invention.
3 is a view showing a micro LED transfer head according to a preferred embodiment of the present invention.
Figure 4 is a view showing the adsorption member of the micro LED transfer head according to a preferred embodiment of the present invention from below.
5 is a perspective view of a micro LED transfer head according to a preferred embodiment of the present invention.

The following merely illustrates the principles of the invention. Therefore, those skilled in the art may implement the principles of the invention and invent various devices included in the concept and scope of the invention, although not explicitly described or illustrated herein. In addition, all conditional terms and embodiments listed herein are in principle clearly intended to be understood only for the purpose of understanding the concept of the invention and are not to be limited to the specifically listed embodiments and states. .

The above objects, features, and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, and thus, it will be possible to easily implement the technical idea of self-invention having ordinary skill in the art. .

Embodiments described herein will be described with reference to cross-sectional and / or perspective views, which are ideal exemplary views of the invention. The thicknesses of the films and regions and the diameters of the holes shown in these figures are exaggerated for the effective explanation of the technical contents. The shape of the exemplary diagram may be modified by manufacturing techniques and / or tolerances. In addition, the number of micro-LEDs shown in the drawings is only a part of the drawings for illustrative purposes. Accordingly, the embodiments of the present invention are not limited to the specific forms shown, but also include changes in forms generated according to manufacturing processes.

In various embodiments of the present disclosure, components that perform the same function will be given the same names and the same reference numbers for convenience, even though the embodiments are different. In addition, the configuration and operation already described in another embodiment will be omitted for convenience.

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

1 is a view illustrating a plurality of micro LEDs 100 to be transferred to a micro LED transfer head according to an exemplary embodiment of the present invention. The micro LEDs 100 are manufactured and positioned on the growth substrate 101.

The growth substrate 101 may be made of a conductive substrate P or an insulating substrate P. For example, the growth substrate 101 may be formed of at least one of sapphire, SiC, Si, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga203.

The micro LED 100 may include a first semiconductor layer 102, a second semiconductor layer 104, an active layer 103 formed between the first semiconductor layer 102 and the second semiconductor layer 104, and a first contact electrode ( 106 and a second contact electrode 107.

The first semiconductor layer 102, the active layer 103, and the second semiconductor layer 104 may be formed of metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), or plasma chemical vapor deposition (CVD). Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), or the like.

The first semiconductor layer 102 may be implemented with, for example, a p-type semiconductor layer. The p-type semiconductor layer is a semiconductor material having a composition formula of InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x + y≤1), for example, GaN, AlN, AlGaN, InGaN, InN , InAlGaN, AlInN, and the like, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped.

The second semiconductor layer 104 may be formed, for example, including an n-type semiconductor layer. The n-type semiconductor layer is a semiconductor material having a composition formula of InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x + y≤1), for example, GaN, AlN, AlGaN, InGaN, InNInAlGaN , AlInN, and the like, and n-type dopants such as Si, Ge, Sn, and the like may be doped.

However, the present invention is not limited thereto, and the first semiconductor layer 102 may include an n-type semiconductor layer, and the second semiconductor layer 104 may include a p-type semiconductor layer.

The active layer 103 is a region where electrons and holes are recombined. The active layer 103 may transition to a low energy level as the electrons and holes recombine, and may generate light having a corresponding wavelength. The active layer 103 may include, for example, a semiconductor material having a compositional formula of InxAlyGa1-x-yN (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1), and It may be formed of a quantum well structure or a multi quantum well structure (MQW). In addition, a quantum wire structure or a quantum dot structure may be included.

The first contact electrode 106 may be formed on the first semiconductor layer 102, and the second contact electrode 107 may be formed on the second semiconductor layer 104. The first contact electrode 106 and / or the second contact electrode 107 may comprise one or more layers and may be formed of various conductive materials including metals, conductive oxides and conductive polymers.

The plurality of micro LEDs 100 formed on the growth substrate 101 are cut along the cutting line using a laser or the like, or separately separated by an etching process, and the plurality of micro LEDs 100 are separated by the laser lift-off process. It can be made to be in a state detachable from 101.

In Figure 1 'p' means the pitch interval between the micro LED 100, 's' means the separation distance between the micro LED 100, 'w' means the width of the micro LED (100).

2 is a view showing a micro LED structure formed by being transferred to a display substrate by a micro LED transfer head according to a preferred embodiment of the present invention.

The display substrate 301 may include various materials. For example, the display substrate 301 may be made of a transparent glass material mainly containing SiO ₂ . However, the display substrate 301 is not necessarily limited thereto, and may be formed of a transparent plastic material to have solubility. Plastic materials include insulating polyethersulphone (PES), polyacrylate (PAR, polyacrylate), polyetherimide (PEI), polyethylene naphthalate (PEN, polyethyelenen napthalate), polyethylene terephthalate (PET) polyethyeleneterepthalate, polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose tri acetate (TAC), cellulose acetate propionate: CAP) may be an organic material selected from the group consisting of.

When the image is a bottom emission type implemented in the direction of the display substrate 301, the display substrate 301 should be formed of a transparent material. However, when the image is a top emission type implemented in a direction opposite to the display substrate 301, the display substrate 301 does not necessarily need to be formed of a transparent material. In this case, the display substrate 301 may be formed of metal.

When the display substrate 301 is formed of metal, the display substrate 301 may be at least one selected from the group consisting of iron, chromium, manganese, nickel, titanium, molybdenum, stainless steel (SUS), Invar alloy, Inconel alloy, and Kovar alloy. It may include, but is not limited thereto.

The display substrate 301 may include a buffer layer 311. The buffer layer 311 may provide a flat surface and may block foreign matter or moisture from penetrating. For example, the buffer layer 311 may be formed of inorganic materials such as silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide, or titanium nitride, or organic materials such as polyimide, polyester, and acryl. And may be formed of a plurality of laminates of the illustrated materials.

The thin film transistor TFT may include an active layer 310, a gate electrode 320, a source electrode 330a, and a drain electrode 330b.

Hereinafter, the thin film transistor TFT will be described as a top gate type in which the active layer 310, the gate electrode 320, the source electrode 330a, and the drain electrode 330b are sequentially formed. However, the present embodiment is not limited thereto, and various types of thin film transistors (TFTs), such as a bottom gate type, may be employed.

The active layer 310 may include a semiconductor material, for example, amorphous silicon or poly crystalline silicon. However, the present embodiment is not limited thereto, and the active layer 310 may contain various materials. In some embodiments, the active layer 310 may contain an organic semiconductor material.

In another alternative embodiment, the active layer 310 may contain an oxide semiconductor material. For example, the active layer 310 may be formed of Group 12, 13, 14 metal elements such as zinc (Zn), indium (In), gallium (Ga), tin (Sn) cadmium (Cd), germanium (Ge), and combinations thereof. Oxides of the selected materials.

A gate insulating layer 313 is formed on the active layer 310. The gate insulating layer 313 insulates the active layer 310 and the gate electrode 320. The gate insulating layer 313 may be formed of a multilayer or a single layer formed of an inorganic material such as silicon oxide and / or silicon nitride.

The gate electrode 320 is formed on the gate insulating layer 313. The gate electrode 320 may be connected to a gate line (not shown) for applying an on / off signal to the thin film transistor TFT.

The gate electrode 320 may be made of a low resistance metal material. The gate electrode 320 is made of aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg) in consideration of adhesion to adjacent layers, surface flatness of the stacked layers, and workability. , Gold (Au), Nickel (Ni), Neodymium (Nd), Iridium (Ir), Chromium (Cr), Lithium (Li), Calcium (Ca), Molybdenum (Mo), Titanium (Ti), Tungsten (W) It may be formed of a single layer or multiple layers of one or more materials of copper (Cu).

An interlayer insulating layer 315 is formed on the gate electrode 320. The interlayer insulating layer 315 insulates the source electrode 330a, the drain electrode 330b, and the gate electrode 320. The interlayer insulating film 315 may be formed of a multilayer or a single layer of an inorganic material. For example, the inorganic material may be a metal oxide or a metal nitride, and specifically, the inorganic material may be silicon oxide (SiO 2), silicon nitride (SiN x), silicon oxynitride (SiON), aluminum oxide (Al 2 O 3), titanium oxide (TiO 2), or tantalum. Oxide (Ta 2 O 5), hafnium oxide (HfO 2), zinc oxide (ZrO 2), or the like.

The source electrode 330a and the drain electrode 330b are formed on the interlayer insulating film 315. The source electrode 330a and the drain electrode 330b include aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), and neodymium (Nd). ), Iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), copper (Cu) of one or more materials Can be formed. The source electrode 330a and the drain electrode 330b are electrically connected to the source region and the drain region of the active layer 310, respectively.

The planarization layer 317 is formed on the thin film transistor TFT. The planarization layer 317 is formed to cover the thin film transistor TFT, thereby eliminating a step resulting from the thin film transistor TFT and making the top surface flat. The planarization layer 317 may be formed of a single layer or multiple layers of an organic material. Organic materials include general purpose polymers such as polymethylmethacrylate (PMMA) and polystylene (PS), polymer derivatives having phenolic groups, acrylic polymers, imide polymers, arylether polymers, amide polymers, fluorine polymers, and p-xylene Polymers, vinyl alcohol-based polymers and blends thereof, and the like. In addition, the planarization layer 317 may be formed of a composite laminate of an inorganic insulating film and an organic insulating film.

The first electrode 510 is positioned on the planarization layer 317. The first electrode 510 may be electrically connected to the thin film transistor TFT. In detail, the first electrode 510 may be electrically connected to the drain electrode 330b through a contact hole formed in the planarization layer 317. The first electrode 510 may have various shapes. For example, the first electrode 510 may be patterned in an island shape. The bank layer 400 defining the pixel region may be disposed on the planarization layer 317. The bank layer 400 may include a recess in which the micro LED 100 is to be accommodated. For example, the bank layer 400 may include a first bank layer 410 forming a recess. The height of the first bank layer 410 may be determined by the height and the viewing angle of the micro LED 100. The size (width) of the recess may be determined by the resolution, the pixel density, and the like of the display device. In one embodiment, the height of the micro LED 100 may be greater than the height of the first bank layer 410. The concave portion may have a rectangular cross-sectional shape, but embodiments of the present invention are not limited thereto, and the concave portion may have various cross-sectional shapes such as polygons, rectangles, circles, cones, ellipses, and triangles.

The bank layer 400 may further include a second bank layer 420 on the first bank layer 410. The first bank layer 410 and the second bank layer 420 may have a step difference, and the width of the second bank layer 420 may be smaller than the width of the first bank layer 410. The conductive layer 550 may be disposed on the second bank layer 420. The conductive layer 550 may be disposed in a direction parallel to the data line or the scan line and electrically connected to the second electrode 530. However, the present invention is not limited thereto, and the second bank layer 420 may be omitted, and the conductive layer 550 may be disposed on the first bank layer 410. Alternatively, the second bank layer 420 and the conductive layer 500 may be omitted, and the second electrode 530 may be formed on the entire substrate P 301 as a common electrode common to the pixels P. . The first bank layer 410 and the second bank layer 420 may include a material that absorbs at least a portion of light, a light reflecting material, or a light scattering material. The first bank layer 410 and the second bank layer 420 may include an insulating material that is translucent or opaque to visible light (eg, light in the wavelength range of 380 nm to 750 nm).

For example, the first bank layer 410 and the second bank layer 420 may include polycarbonate (PC), polyethylene terephthalate (PET), polyethersulfone, polyvinylbutyral, polyphenylene ether, polyamide, poly Thermoplastic resins such as etherimide, norbornene system resins, methacryl resins, cyclic polyolefins, epoxy resins, phenol resins, urethane resins, acrylic resins, vinyl ester resins, imide resins, urethane resins, and urea It may be formed of a thermosetting resin such as resin, melamine resin, or an organic insulating material such as polystyrene, polyacrylonitrile, polycarbonate, but is not limited thereto.

As another example, the first bank layer 410 and the second bank layer 420 may be formed of an inorganic insulating material such as inorganic oxides such as SiOx, SiNx, SiNxOy, AlOx, TiOx, TaOx, ZnOx, and inorganic nitride. It is not limited to this. In one embodiment, the first bank layer 410 and the second bank layer 420 may be formed of an opaque material, such as a black matrix material. Insulating black matrix materials include organic resins, resins or pastes comprising glass paste and black pigments, metal particles such as nickel, aluminum, molybdenum and alloys thereof, metal oxide particles (eg chromium oxide), Or metal nitride particles (eg, chromium nitride) or the like. In a modification, the first bank layer 410 and the second bank layer 420 may be distributed Bragg reflectors (DBRs) having high reflectivity or mirror reflectors formed of metal.

The micro LED 100 is disposed in the recess. The micro LED 100 may be electrically connected to the first electrode 510 in the recess.

The micro LED 100 emits light having a wavelength of red, green, blue, white, and the like, and white light may be realized by using a fluorescent material or combining colors. The micro LED 100 has a size of 1 μm to 100 μm. The micro LEDs 100 are individually or plurally picked up on the growth substrate 101 by the transfer head according to the exemplary embodiment of the present invention, and transferred to the display substrate 301 so that the recesses of the display substrate 301 can be obtained. Can be accommodated in

The micro LED 100 includes a p-n diode, a first contact electrode 106 disposed on one side of the p-n diode, and a second contact electrode 107 positioned opposite to the first contact electrode 106. The first contact electrode 106 may be connected to the first electrode 510, and the second contact electrode 107 may be connected to the second electrode 530.

The first electrode 510 may include a reflective film formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a compound thereof, and a transparent or translucent electrode layer formed on the reflective film. The transparent or translucent electrode layer may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In2O3) and indium gallium oxide (IGO). at least one selected from the group consisting of indium gallium oxide) and aluminum zinc oxide (AZO).

The passivation layer 520 surrounds the micro LED 100 in the recess. The passivation layer 520 fills the space between the bank layer 400 and the micro LED 100 to cover the recess and the first electrode 510. The passivation layer 520 may be formed of an organic insulating material. For example, the passivation layer 520 may be formed of acrylic, poly (methyl methacrylate) (PMMA), benzocyclobutene (BCB), polyimide, acrylate, epoxy, polyester, and the like, but is not limited thereto. It is not.

The passivation layer 520 is formed above the micro LED 100, for example, at a height not covering the second contact electrode 107, so that the second contact electrode 107 is exposed. A second electrode 530 electrically connected to the exposed second contact electrode 107 of the micro LED 100 may be formed on the passivation layer 520.

The second electrode 530 may be disposed on the micro LED 100 and the passivation layer 520. The second electrode 530 may be formed of a transparent conductive material such as ITO, IZO, ZnO, or In 2 O 3.

Hereinafter, the micro LED transfer head 1000 according to an exemplary embodiment of the present invention will be described with reference to FIGS. 3 to 5.

As shown in FIG. 3, the micro LED transfer head 1000 includes an adsorption member 1100, a support member 1210 provided on an upper surface of the adsorption member 1100, and a suction hole 1200a, and the support member 1210. It is configured to include a communication member 1200 coupled to the top of the). The micro LED transfer head 1000 is a vacuum capable of absorbing the micro LED (ML) by supplying the vacuum supplied from the vacuum pump (not shown) to the suction hole (1200a) of the communication member 1200 through the pipe 1001. Pneumatic pressure can be created.

The adsorption member 1100 is formed of a porous adsorption member having vertical pores 1100a. The pores 1100a are formed to vertically penetrate the adsorption member 1100 using a laser, etching, or the like. The vertical pores 1100a formed in the adsorption member 1100 are formed of one pore 1100a corresponding to one micro LED ML disposed on the substrate P or correspond to one micro LED ML. It may be formed of a plurality of pores. Hereinafter, the vertical pores 1100a formed in the adsorption member 1100 will be described as being formed with one pore 1100a corresponding to one micro LED ML disposed on the substrate P.

The adsorption member 1100 may be formed of a material such as metal, nonmetal, ceramic, glass, quartz, silicon (PDMS), resin, or the like, as long as the pore 1100a may have a width of several tens of micrometers or less. Adsorption member 1100 may have the advantage of preventing the generation of static electricity when the transfer of the micro LED (ML) when the material is a metal material. When the material of the adsorption member 1100 is a non-metallic material, the material does not have a metal property and has an advantage of minimizing the influence of the adsorption member 1100 on the micro LED (ML) having a metal property. When the adsorption member 1100 is made of a material such as ceramic, glass, quartz, etc., it is advantageous to secure rigidity, and the thermal expansion coefficient is low, so that a position error occurs due to thermal deformation of the adsorption member 1100 during transfer of the micro LED (ML). Concerns can be minimized. If the adsorption member 1100 is made of silicon or PDMS material, even if the lower surface of the adsorption member 1100 is in direct contact with the upper surface of the micro LED ML, the absorbing function is performed to prevent the damage caused by the collision with the micro LED ML. It can be minimized. When the material of the adsorption member 1100 is a resin material, the adsorption member 1100 may be easily manufactured.

Meanwhile, the adsorption member 1100 may be an anodization film formed by anodizing a metal. The anodization film refers to a film formed by anodizing a base metal, and the pores in the anodization film refer to holes formed in a process of forming an anodization film by anodizing a metal. For example, when the base metal is aluminum (AL) or an aluminum alloy, the base material is anodized to form an anodized film made of anodized aluminum (Al ₂ O ₃ ) on the surface of the base material. As described above, the formed anodization film is divided into a barrier layer in which pores are not formed therein and a porous layer in which pores are formed therein. The barrier layer is located on top of the base material, and the porous layer is located on top of the barrier layer. As such, when the base material is removed from the base material on which the anodized film having the barrier layer and the porous layer is formed on the surface, only the anodized film 1121 of aluminum anodized (Al ₂ O ₃ ) material remains. The anodic oxide film has pores having a regular arrangement while having a uniform diameter and a vertical shape. Therefore, when the barrier layer is removed, the pores vertically and vertically penetrate the structure, thereby making it easy to form a vacuum pressure in the vertical direction.

The inside of the anodic oxide film can form an air flow path in a vertical form by vertical pores. The inner width of the pores has a size of several nm to several hundred nm.

When etching is performed on such an anodization film using a mask, a hole having a vertical shape is formed. The hole is formed to have a wider width than a pore such as a hole naturally formed in the anodic oxide film, and the hole becomes a pore 1100a of the porous adsorption member having vertical pores 1100a. As such, when the anodization film is used as the material of the adsorption member 1100, the shape of the pores 1100a is perpendicular to the z-axis direction by using the fact that the anodization film can form vertical pores 1100a in response to the etching solution. It can be formed.

In addition, the thermal expansion coefficient of the anodic oxide film is 2 to 3 ppm / ℃ it is possible to minimize the thermal deformation by the ambient heat in the micro LED adsorbent 1000 of the second embodiment to absorb and transfer the micro LED (ML), It is possible to exert an effect that the fear of position error is significantly lowered.

The pores 1100a formed in the suction member 1100 are spaced apart at regular intervals in the x (row) direction and the y (column) direction. The pores 1100a are spaced apart from each other by at least two times the pitch intervals in the x and y directions of the micro LEDs ML disposed on the substrate P in at least one of the x and y directions. The substrate P may be the growth substrate 101 illustrated in FIG. 1, or the display substrate 301 illustrated in FIG. 2 to which the micro LEDs ML adsorbed by the growth substrate 101 are transferred.

As such, the micro LED transfer head 1000 including the adsorption member 1100 having the vertical pores 1100a is lowered to the substrate P side to selectively select the micro LEDs ML located at positions corresponding to the pores 1100a. Adsorb. Here, the micro LED ML disposed on the substrate P may be any one of red, green, and blue LEDs. For example, the pores 1100a formed in the adsorption member 1100 are spaced at a distance of three times the pitch interval in the x direction of the micro LED ML disposed on the substrate P, and the distance of one times the pitch interval in the y direction. Are spaced apart. The micro LED transfer head 1000 selectively absorbs the micro LEDs ML disposed at predetermined intervals in the x and y directions on the substrate P to reciprocate a plurality of times (for example, three times) to display the substrate 301. ) Or a 1 × 3 pixel array can be formed by transferring to a temporary substrate or a carrier substrate transferred from the growth substrate 101.

The pores 1100a are not formed between the pores 1100a as the pores 1100a are spaced apart by two or more times the pitch intervals in the x and y directions of the micro LEDs ML disposed on the substrate P. The non-forming part 10 is formed. The non-porous portion 10 may be provided with a support member 1210. The support member 1210 is formed in the pore non-forming portion 10 formed between the pores 1100a while the pores 1100a are formed to be spaced apart at least twice the pitch intervals in the x and y directions of the micro LED ML. It may be provided. The pore non-forming part 10 may form a non-adsorption area of the adsorption surface of the adsorption member 1100 since the vacuum supplied through the pipe 1001 is not transferred. In other words, as the pores 1100a are spaced apart from each other, the support member is formed on the upper surface of the non-adsorption area 20 of the adsorption surface formed by the non-pore forming portion 10 in which the pores 1100a are not formed between the pores 1100a. 1210 may be provided. 3 illustrates that the pores 1100a of the adsorption member 1100 are spaced apart in the x direction at a distance not less than twice the pitch interval in the x direction of the micro LED ML disposed on the substrate P. Referring to FIG. As such, the pore non-forming part 10 provided with the supporting member 1210 may refer to the pore non-forming part 10 in the x direction of the adsorption member 1100. Therefore, the support member 1210 is provided on the upper surface of the non-adsorption area 20 of the adsorption surface of the adsorption member 1100 formed by the non-porous portion 10, the non-adsorption area 20 of the adsorption member 1100. It may be provided in the upper direction of the x direction.

4 is a view showing the bottom surface of the adsorption member 1100. As shown in FIG. 4, a support member 1210 is provided between the pores 1100a in the x direction based on the pores 1100a of the adsorption member 1100.

5 (a) is before the communication member 1200 coupled to the adsorption member 1100 of the micro LED transfer head 1000 of the present invention, the support member 1210 is coupled to the upper portion of the adsorption member 1100. 5 (b) shows a state in which the communication member 1200 is coupled to the upper portion of the adsorption member 1100 of the micro LED transfer head 1000 of the present invention through the support member 1210. It is a degree.

Referring to FIG. 3 again, FIG. 3 (a) is a cross-sectional view taken along line A of FIG. 5 (b), and FIG. 3 (b) is taken along line B of FIG. 5 (b). It is a figure which shows a cross section. As shown in FIG. 3A, the micro LEDs ML are disposed on the substrate P at pitch intervals as long as the distance P (ML) in the x direction. Correspondingly, the pores formed in the adsorption member 1100 are spaced apart by a predetermined distance as much as P (H) distance in the x direction. Here, the distance in the x direction between the pores 1100a is three times the distance of the micro LED ML disposed on the substrate P. FIG. A support member 1210 may be provided in the non-pore portion 10 formed while being spaced apart from the pores 1100a in the x direction. The pore non-forming part 10 may be an upper surface of the non-adsorption area 20 of the adsorption member 1100. Therefore, the support member 1210 is provided on the upper surface of the non-adsorption area 20 of the suction member 1100 in the x direction.

Although not shown in the drawings, when the distance in the y direction between the pores 1100a is three times the distance of the micro LED ML disposed on the substrate P, the pore non-type is formed while being spaced between the pores 1100a in the y direction. The support member 1210 may be provided in the voice portion.

The support member 1210 is provided on the upper surface of the non-adsorption area of the suction member 1100 to support the load of the communication member 1200 coupled to the upper portion of the support member 1210. Therefore, even if the pores 1100a are provided to provide the air flow paths perpendicular to the adsorption member 1100, the problem of the strength of the adsorption member 1100 is reduced. In detail, the adsorption member 1100 having the fine vertical pores 1100a formed by etching or laser is thin in order to easily form the vertical pores 1100a. When the thickness of the suction member 1100 is thin, it may be difficult to support a load such as a communication member 1200 coupled to the upper portion of the suction member 1100 and a vacuum pressure chamber for supplying a vacuum. Therefore, the present invention can support the load of the communication member 1200 and the vacuum chamber coupled to the upper portion of the adsorption member 1100 by providing the support member 1210 in the non-porous portion 10. In addition, the support member 1210 functions as a boundary that separates the region 30 between the support member 1210 in which the pores 1100a are formed and the non-pore portion 10, and the region between the support member 1210 ( It may serve as a partition so that 30) becomes a vacuum forming compartment. As a result, a uniform vacuum pressure may be easily formed in the region 30 between the support members 1210.

An upper portion of the support member 1210 is a communication member 1200 which is coupled to the support member 1210 to communicate air between the regions 30 between the support member 1210. The communication member 1200 may be made of a non-porous material such as a metal material to form a suction hole 1200a. The suction hole 1200a is formed in a structure that vertically penetrates the communication member 1200 so that the communication member 1200 is coupled to the upper portion of the support member 1210 to transfer the vacuum supplied from the vacuum pump. The pipe 1001 is connected. As a result, a vacuum is supplied to the adsorption member 1100 so that the adsorption force may occur.

The communicating member 1200 has a groove 1200b intersecting the supporting member 1210 on the bottom surface thereof. The groove 1200b provided in the communication member 1200 may be provided to intersect the support member 1210 on the lower surface of the communication member 1200. The communicating member 1200 has a groove 1200b intersecting the supporting member 1210 on the bottom surface thereof, so that the vacuum supplied through the suction hole 1200a is uniformly applied to the regions 30 between the supporting members 1210. Can be distributed and in air communication.

As shown in FIG. 3 (a), the communicating member 1200 is provided with a groove 1200b intersecting the supporting member 1210 at a lower surface of the communicating member 1200, thereby providing an area 30 between the supporting members 1210. ) Can be in air communication. As a result, the vacuum supplied through the suction hole 1200a is distributed throughout the regions 30 between the support members 1210. The regions 30 between the support members 1210 may be upper surfaces of the adsorption region 20 of the adsorption member 1100. The adsorption region 20 of the adsorption member 1100 is formed by transferring a vacuum supplied through the suction hole 1200a to the pores 1100a of the adsorption member 1100. Therefore, when the region 30 between the support members 1210 is in air communication and the vacuum supplied through the suction hole 1200a is uniformly distributed to the entire region between the support members 1210, the suction member 1100 may be The adsorption force of all the adsorption zones 20 can be generated uniformly. Thus, efficient transfer may be performed without the problem that the micro LEDs ML are not adsorbed on the adsorption surface of the micro LED transfer head 1000.

In the drawings of FIGS. 3 to 5, a plurality of grooves 1200b are provided to intersect the support member 1210 on the lower surface of the communication member 1200 so as to allow air communication between the regions 30 between the support members 1210. Although illustrated as being, at least one is provided to cross the support member 1210 on the lower surface of the communication member 1200 may be in air communication between the regions 30 between the support member 1210. In addition, the groove 1200b provided to intersect the support member 1210 of the communication member 1200 is formed to be smaller than the width and thickness of the communication member 1200 to allow air between the regions 30 between the support members 1210. Can be.

On the other hand, the communication member 1200 may be composed of a porous member having pores.

The porous member includes a material containing a large number of pores therein, and may be composed of a powder, a thin film / thick film, and a bulk having a porosity of about 0.2 to 0.95 in a predetermined arrangement or a disordered pore structure. The pores of the porous member can be classified into micro pores of 2 nm or less in diameter, meso pores of 2 to 50 nm, and macro pores of 50 nm or more, depending on the size thereof. Include. Porous members can be classified into organic, inorganic (ceramic), metal, and hybrid porous materials according to their constituents. The porous member may be powder, coating film, or bulk in terms of shape, and in the case of powder, various shapes such as spherical, hollow spherical, fiber, and tubular are possible, and in some cases, the powder may be used as it is. It is also possible to manufacture and use a bulk shape.

When the pores of the porous member have a disordered pore structure, the inside of the porous member forms a flow path connecting the top and bottom of the porous member while the plurality of pores are connected to each other. Such a porous member may be porous by sintering an aggregate composed of inorganic material granules and a binder bonding the aggregates together. In this case, the porous member has a plurality of pores irregularly connected to each other to form a gas flow path, and the surface and the back surface of the porous member communicate with each other by the gas flow path.

When the communication member 1200 is composed of a porous member having pores, it may function to support the adsorption member 1100 like the support member 1210. In this case, the communication member composed of the porous member may be a porous support. The porous member is not limited to the material as long as it can achieve the function of supporting the adsorption member, it may include the configuration of the porous member described above. The communicating member 1200 is composed of a porous member, when composed of a rigid porous support having an effect of preventing the central sag of the adsorption member 1100, the communicating member 1200 may be a porous ceramic material.

When the communicating member 1200 is a porous member having pores, a vacuum chamber (not shown) is coupled to the upper portion of the communicating member 1200. The vacuum chamber may be connected to the pipe 1001 so that the vacuum supplied from the vacuum pump may be delivered to the pores of the communicating member 1200. The vacuum applied to the pores of the communication member 1200 through the vacuum chamber is transferred to the adsorption member 1100. In this case, a vacuum may be transmitted to the regions 30 between the support members 1210 provided on the upper surface of the suction member 1100 through the pores of the communication member 1200. As a result, adsorption force may be generated in the adsorption region 20 of the adsorption member 1100, so that the micro LED ML may be adsorbed onto the adsorption surface of the adsorption member 1100.

The lower surface of the communication member 1200 made of a porous member having pores may be provided with a groove 1200b crossing the support member 1210. The vacuum delivered by the vacuum chamber is delivered to the pores of the communicating member 1200. The vacuum transferred to the pores may be uniformly distributed in the regions 30 between the support members 1210 in air communication by the grooves 1200b intersecting the support members 1210 on the lower surface of the communication member 1200. . As a result, a uniform adsorption force may be generated in the adsorption region 20, and the micro LED ML may be transferred to the adsorption surface without missing.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art various modifications of the present invention without departing from the spirit and scope of the invention described in the claims below. Or it may be modified.

1000: micro LED transfer head 1001: piping
1100: adsorption member 1100a: pores
1200: communication member 1200a: suction hole
1200b: groove 1210: support member
10: pore non-forming part 20: adsorption area
30: area between supporting members

Claims (7)

Adsorption member for adsorbing micro LED;
A support member provided on an upper surface of the non-adsorption area of the suction member; And
And a communication member coupled to the support member at an upper portion of the support member and configured to communicate air between regions between the support members.
The method of claim 1,
The communication member is a micro LED transfer head, characterized in that a groove crossing the support member is provided on the lower surface.
The method of claim 1,
The communication member is a micro LED transfer head, characterized in that the porous member having pores.
The method of claim 1,
The adsorption member is a micro LED transfer head, characterized in that the porous adsorption member having vertical pores.
The method of claim 1,
The adsorption member is a micro LED transfer head, characterized in that the anodic oxidation film formed by anodizing a metal.
The method of claim 2,
The communication member is a micro LED transfer head, characterized in that the suction hole is formed.
The method of claim 3,
Micro LED transfer head, characterized in that the vacuum chamber is coupled to the upper portion of the communication member.

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