KR102540860B1 - Transfer head for micro led and micro led transfer system using the same - Google Patents

Abstract

The present invention relates to a micro LED transfer head and a micro LED transfer system using the same, which can improve the transfer efficiency of the micro LED transfer head by preventing factors that interfere with the adsorption force when the micro LED transfer head adsorbs the micro LED.

Description

Micro LED transfer head and micro LED transfer system using the same {TRANSFER HEAD FOR MICRO LED AND MICRO LED TRANSFER SYSTEM USING THE SAME}

The present invention relates to a micro LED transfer head and a micro LED transfer system for transferring a micro LED using the same.

In the current display market, while LCD is still the mainstream, OLED is rapidly replacing LCD and emerging as the mainstream. In a situation where display companies are rushing to participate in the OLED market, Micro LED (hereinafter referred to as 'Micro LED') display is emerging as another next-generation display. While the core materials of LCD and OLED are liquid crystal and organic materials, respectively, micro LED display is a display that uses 1-100 micrometer (㎛) LED chips themselves as light emitting materials.

In 1999, when Cree applied for a patent on "a micro-light emitting diode array with improved light extraction" (Registration Patent Publication Registration No. 0731673), the term micro LED appeared, and related research papers were published one after another, research and development this is being done As a task to be solved in order to apply micro LED to a display, it is necessary to develop a customized micro chip based on a flexible material/device for a micro LED device, transfer of a micrometer size LED chip and accurate display pixel electrode. Skills for mounting are required.

In particular, in relation to the transfer of the micro LED device to the display substrate, as the size of the LED decreases to 1 to 100 micrometers (μm), conventional pick and place equipment cannot be used. There is a need for a transfer head technology that transfers with higher precision. Regarding the transfer head technology, several structures have been proposed as described below, but each proposed technology has several disadvantages.

Luxvue of the United States proposed a method of transferring micro LEDs using an electrostatic head (Patent Publication No. 2014-0112486, hereinafter referred to as 'Prior Invention 1'). X-Celeprint of the United States proposed a method of transferring micro LEDs on a wafer to a desired substrate by applying a transfer head made of an elastic polymer material (Patent Publication No. 2017-0019415, hereinafter referred to as 'Prior Invention 2'). box). The Korea Institute of Optical Technology proposed a method of transferring micro LEDs using a ciliary adhesive structure head (Registration Patent Publication No. 1754528, hereinafter referred to as 'Prior Invention 3'). The Korea Institute of Machinery and Materials proposed a method of transferring micro LEDs by coating an adhesive on a roller (Registration Patent Publication Registration No. 1757404, hereinafter referred to as 'Prior Invention 4'). Samsung Display has proposed a method of transferring micro LEDs to an array substrate by electrostatic induction by applying a negative voltage to the first and second electrodes of the array substrate while the array substrate is immersed in a solution (Public Patent Publication No. 10- 2017-0026959, hereinafter referred to as 'Prior Invention 5'). LG Electronics has proposed a method of disposing a head holder between a plurality of pickup heads and a substrate and providing a degree of freedom to the plurality of pickup heads by deforming the shape by movement of the plurality of pickup heads (Public Patent Publication No. 10). -2017-0024906, hereinafter referred to as 'Prior Invention 6').

The above prior inventions 1 to 6 focus only on how to transfer the micro LED. However, in transferring the micro LED from the first substrate to the second substrate, when the transfer head adsorbs and detaches the micro LED, it has not been suggested how to remove the interfering factors that hinder adsorption and desorption.

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

Therefore, the present invention is to provide a micro LED transfer head and a micro LED transfer system using the same, which can improve the transfer efficiency of the micro LED transfer head by preventing factors that interfere with the adsorption force when the micro LED transfer head adsorbs the micro LED. The purpose.

A micro LED transfer head according to one feature of the present invention, in the micro LED transfer head adsorbing the micro LED with an adsorption surface, is characterized in that it includes a shield formed on an edge so as to protrude downward from the adsorption surface.

In addition, the shield portion is characterized in that composed of an elastic material.

In addition, the shield unit is characterized in that when the micro LED transfer head adsorbs the micro LED, an external factor interfering with the adsorption force is blocked from penetrating into the transfer space.

In addition, the micro LED transfer head is a micro LED transfer head using electrostatic force, and when the shield unit adsorbs the micro LED with the electrostatic force, a factor obstructing the electrostatic force of the micro LED transfer head is introduced into the transfer space. characterized by preventing

In addition, the micro LED transfer head is a micro LED transfer head using a suction force, and when the shield unit adsorbs the micro LED with the suction force, a factor obstructing the suction force of the micro LED transfer head is introduced into the transfer space. characterized by preventing

In addition, the micro LED transfer head is a micro LED transfer head using magnetic force, and when the shield unit adsorbs the micro LED with the magnetic force, a factor that interferes with the micro LED transfer head magnetic force is prevented from entering into the transfer space. It is characterized by doing.

In addition, the micro LED transfer head is a micro LED transfer head using van der Waals force, and when the shield unit adsorbs the micro LED with the van der Waals force, a factor obstructing the micro LED transfer head van der Waals force It is characterized in that it prevents the inflow into the transfer space.

A micro LED transfer system according to another feature of the present invention includes a micro LED transfer head including a shield portion formed on an edge to adsorb a micro LED to an adsorption surface and protrude downward from the adsorption surface; A first substrate chipped with micro LEDs; and a support member installed below the first substrate to support the first substrate, wherein when the micro LED of the first substrate is transferred to the absorption surface, the shield unit is attached to the support member or the first substrate. It is characterized by contacting the upper surface.

In addition, it is characterized in that the transfer space is formed while the lower end of the micro LED transfer head is spaced apart from the upper surface of the micro LED of the first substrate.

In addition, the shield unit is characterized in that when the micro LED transfer head adsorbs the micro LED, an external factor interfering with the adsorption force is blocked from penetrating into the transfer space.

A micro LED transfer system according to another feature of the present invention includes a micro LED transfer head for adsorbing a micro LED with an adsorption surface; A first substrate chipped with micro LEDs; a support member supporting the first substrate; and a shield part formed on an edge of the support member to protrude upward from the support member or formed on an edge of the first substrate to protrude upward from the first substrate.

In addition, the shield portion is characterized in that composed of an elastic material.

In addition, when the micro LED of the first substrate is transferred to the adsorption surface, the shield unit is in contact with the lower surface of the rim of the micro LED transfer head.

In addition, it is characterized in that the transfer space is formed while the lower end of the micro LED transfer head is spaced apart from the upper surface of the micro LED of the first substrate.

In addition, the shield unit is characterized in that when the micro LED transfer head adsorbs the micro LED, an external factor interfering with the adsorption force is blocked from penetrating into the transfer space.

As described above, the micro LED transfer head and the micro LED transfer system using the same according to the present invention seal the transfer space where micro LED transfer is performed, so that external factors that hinder the adsorption force of the micro LED transfer head penetrate into the transfer space. By blocking this, there is an effect of improving the transfer efficiency by preventing external factors that hinder the adsorption force from being adsorbed on the adsorption surface of the micro LED transfer head and deteriorating the adsorption force.

1 is a diagram showing a micro LED as a transfer target of embodiments of the present invention;
2 is a diagram of a micro LED structure transferred and mounted on a display board according to embodiments of the present invention;
Figure 3 (a) is a diagram showing a state before operation of the micro LED transfer system according to the first embodiment of the present invention.
Figure 3 (b) is a diagram showing a state after operation of the micro LED transfer system according to the first embodiment of the present invention.
Figure 4 shows a micro LED transfer system according to a second embodiment of the present invention.

The following merely illustrates the principles of the invention. Therefore, those skilled in the art can invent various devices that embody the principles of the invention and fall within the concept and scope of the invention, even though not explicitly described or shown herein. In addition, it should be understood that all conditional terms and embodiments listed in this specification are, in principle, expressly intended only for the purpose of making the concept of the invention understood, and are not limited to such specifically listed embodiments and conditions. .

The above objects, features and advantages will become more apparent through the following detailed description in conjunction with the accompanying drawings, and accordingly, those skilled in the art to which the invention belongs will be able to easily implement the technical idea of the invention. .

Embodiments described in this specification will be described with reference to sectional views and/or perspective views, which are ideal exemplary views of the present invention. Thicknesses of films and regions and diameters of holes shown in these drawings are exaggerated for effective description of the technical content. The shape of the illustrative drawings may be modified due to manufacturing techniques and/or tolerances. In addition, the number of micro LEDs shown in the drawing is shown in the drawing by way of example only. Therefore, embodiments of the present invention are not limited to the specific shapes shown, but also include changes in shapes generated according to manufacturing processes.

In describing various embodiments, the same names and the same reference numbers will be given to components performing the same functions even if the embodiments are different. In addition, configurations and operations already described in other embodiments will be omitted for convenience.

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

1 is a diagram showing a micro LED as a transfer target of embodiments of the present invention, and FIG. 2 is a diagram of a micro LED structure transferred and mounted according to embodiments of the present invention.

FIG. 1 is a diagram showing a plurality of micro LEDs 100 to be adsorbed by a micro LED transfer head according to a preferred embodiment of the present invention. The micro LED 100 is fabricated and positioned on the growth substrate 101 .

The growth substrate 101 may be formed of a conductive substrate or an insulating substrate. 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 Ga ₂ O ₃ .

The micro LED 100 includes 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 by metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), or plasma chemical vapor deposition (CVD). It can be formed using methods such as plasma-enhanced chemical vapor deposition (PECVD), molecular beam epitaxy (MBE), and hydride vapor phase epitaxy (HVPE).

The first semiconductor layer 102 may be implemented as, 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, etc., and a p-type dopant such as Mg, Zn, Ca, Sr, or Ba may be doped. The second semiconductor layer 104 may include, for example, 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, etc., and an n-type dopant such as Si, Ge, or Sn 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 recombine, and as electrons and holes recombine, the active layer 103 transitions to a lower energy level and can generate light having a wavelength corresponding thereto. The active layer 103 may include, for example, a semiconductor material having a composition formula of InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x+y≤1), and may be formed by a single It may be formed in a quantum well structure or a multi quantum well (MQW) structure. In addition, a quantum wire structure or a quantum dot structure may be included.

A first contact electrode 106 may be formed on the first semiconductor layer 102 , and a 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 include 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 can be separated from the growth substrate 101 .

In FIG. 1, 'p' means the pitch interval between the micro LEDs 100, 's' means the separation distance between the micro LEDs 100, and 'w' means the width of the micro LEDs 100.

2 is a view showing a micro LED structure formed by being transferred and mounted on 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 containing SiO ₂ as a main component. However, the display substrate 301 is not necessarily limited thereto, and may be formed of a transparent plastic material and have solubility. The plastic materials are insulating organic materials such as polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethyelenen napthalate (PEN), polyethylene terephthalate (PET, polyethyleneterepthalate), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate: CAP) may be an organic material selected from the group consisting of.

In the case of a bottom emission type displaying an image in the direction of the display substrate 301, the display substrate 301 should be formed of a transparent material. However, in the case of a top emission type in which an image is implemented in a direction opposite to that of the display substrate 301, the display substrate 301 does not necessarily need to be made 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 is one or more selected from the group consisting of iron, chromium, manganese, nickel, titanium, molybdenum, stainless steel (SUS), an Invar alloy, an Inconel alloy, and a 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 penetration of foreign substances or moisture. For example, the buffer layer 311 is made of an inorganic material such as silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide, or titanium nitride, or an organic material such as polyimide, polyester, or acryl. It may contain, and may be formed of a plurality of laminates among the materials exemplified.

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, a case in which the thin film transistor (TFT) is a top gate type in which an active layer 310, a gate electrode 320, a source electrode 330a, and a drain electrode 330b are sequentially formed will be described. 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 polycrystalline silicon. However, the present embodiment is not limited thereto, and the active layer 310 may contain various materials. As an optional embodiment, the active layer 310 may contain an organic semiconductor material or the like.

As another optional embodiment, the active layer 310 may contain an oxide semiconductor material. For example, the active layer 310 is made of metal elements of groups 12, 13, and 14, such as zinc (Zn), indium (In), gallium (Ga), tin (Sn), cadmium (Cd), and germanium (Ge), and combinations thereof. It may contain oxides of selected materials.

A gate insulating layer 313 is formed on the active layer 310 . The gate insulating layer 313 serves to insulate the active layer 310 and the gate electrode 320 . The gate insulating layer 313 may be formed of a multilayer or a single layer 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, for example, aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg) in consideration of adhesion to adjacent layers, surface flatness and processability of the stacked layer, and the like. , Gold (Au), Nickel (Ni), Neodymium (Nd), Iridium (Ir), Chromium (Cr), Lithium (Li), Calcium (Ca), Molybdenum (Mo), Titanium (Ti), Tungsten (W) , Copper (Cu) may be formed as a single layer or multiple layers.

An interlayer insulating film 315 is formed on the gate electrode 320 . The interlayer insulating film 315 insulates the source electrode 330a and the drain electrode 330b from the gate electrode 320 . The interlayer insulating film 315 may be formed of a multi-layer or single-layer film made 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 (SiNx), silicon oxynitride (SiON), aluminum oxide (Al ₂ O ₃ ), titanium oxide ( TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), hafnium oxide (HfO ₂ ), or zinc oxide (ZrO ₂ ).

A source electrode 330a and a drain electrode 330b are formed on the interlayer insulating layer 315 . The source electrode 330a and the drain electrode 330b may include aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), or neodymium (Nd). ), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), copper (Cu) in a single layer or multi-layer can be formed The source electrode 330a and the drain electrode 330b are electrically connected to the source and drain regions 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), eliminates the step caused by the thin film transistor (TFT), and flattens the upper surface. The planarization layer 317 may be formed of a single layer or multiple layers of a film made 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. It may include polymers, vinyl alcohol-based polymers, and blends thereof. Also, the planarization layer 317 may be formed of a composite laminate of an inorganic insulating film and an organic insulating film.

A first electrode 510 is positioned on the planarization layer 317 . The first electrode 510 may be electrically connected to the thin film transistor (TFT). Specifically, 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, may be patterned and formed in an island shape. A bank layer 400 defining a pixel area may be disposed on the planarization layer 317 . The bank layer 400 may include a concave portion in which the micro LED 100 is accommodated. The bank layer 400 may include, for example, a first bank layer 410 forming a concave portion. The height of the first bank layer 410 may be determined by the height and viewing angle of the micro LED 100 . The size (width) of the concave portion may be determined by the resolution and pixel density 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 square 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 polygonal, rectangular, circular, conical, elliptical, and triangular shapes.

The bank layer 400 may further include a second bank layer 420 over the first bank layer 410 . The first bank layer 410 and the second bank layer 420 have a step difference, and the width of the second bank layer 420 may be smaller than that of the first bank layer 410 . A 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 over the entire substrate 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 reflection 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 a wavelength range of 380 nm to 750 nm).

For example, the first bank layer 410 and the second bank layer 420 may be formed of polycarbonate (PC), polyethylene terephthalate (PET), polyethersulfone, polyvinylbutyral, polyphenylene ether, polyamide, or polyether. Etherimide, norbornene system resin, methacrylic resin, thermoplastic resin such as cyclic polyolefin, epoxy resin, phenol resin, urethane resin, acrylic resin, vinyl ester resin, imide resin, urethane resin, urea It may be formed of a thermosetting resin such as resin or melamine resin, or an organic insulating material such as polystyrene, polyacrylonitrile, or 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 an inorganic oxide or inorganic nitride such as SiOx, SiNx, SiNxOy, AlOx, TiOx, TaOx, or ZnOx. 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. Insulative black matrix materials include organic resins, glass paste and resins or pastes containing black pigments, metal particles such as nickel, aluminum, molybdenum and alloys thereof, metal oxide particles (e.g., chromium oxide), or metal nitride particles (eg, chromium nitride) and the like. In a modified example, the first bank layer 410 and the second bank layer 420 may be a distributed Bragg reflector (DBR) having high reflectivity or a mirror reflector formed of metal.

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

The micro LED 100 emits light having wavelengths such as red, green, blue, and white, and white light can be implemented 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 picked up on the growth substrate 101 by the transfer head according to the embodiment of the present invention and transferred to the display substrate 301 individually or in plurality, thereby forming a concave portion of the display substrate 301. can be accepted 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 disposed on the opposite side of 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 is indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In ₂ O ₃ ; indium oxide), indium gallium It may include at least one selected from the group including indium gallium oxide (IGO) and aluminum zinc oxide (AZO).

A passivation layer 520 surrounds the micro LED 100 in the recess. The passivation layer 520 covers the concave portion and the first electrode 510 by filling the space between the bank layer 400 and the micro LED 100 . 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, and polyester, but is limited thereto. It is not.

The passivation layer 520 is formed at a height not covering the top of the micro LED 100, for example, 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 .

Example 1

3(a) is a diagram showing a state before the micro LED transfer head 1000 of the micro LED transfer system 1 according to the first preferred embodiment of the present invention descends, and FIG. 3(b) shows the first state. It is a diagram showing a state after the micro LED transfer head 1000 of the micro LED transfer system 1 of the embodiment descends.

The micro LED transfer system 1 according to the first embodiment of the present invention is a micro LED transfer head 1000 for adsorbing a micro LED 100 with an adsorption surface, and a shield portion formed on an edge so as to protrude downward from the adsorption surface. A micro LED transfer head 1000 including 1100, a first substrate 101 chipped with the micro LED 100, and a lower portion of the first substrate 101 to support the first substrate 101 It is configured to include a support member 1200. The first substrate 101 of the first embodiment is a substrate on which the micro LED 100 is fabricated and positioned, and may have the same meaning as the growth substrate 101 of FIG. 1 described above. Accordingly, the same reference numerals are used in the drawings referred to in the following description.

Referring to FIG. 3, the micro LED transfer head 1000 constituting the micro LED transfer system 1 according to the first preferred embodiment of the present invention will be described.

The micro LED transfer head 1000 may adsorb the micro LED 100 with an adsorption surface. The micro LED transfer head 1000 is configured to include a shield portion formed on the rim so as to protrude downward from the adsorption surface, so that the micro LED 100 can be adsorbed or detached from the adsorption surface.

As shown in FIGS. 3(a) and 3(b), a shield unit 1100 is formed on the edge of the micro LED transfer head 1000 so as to protrude downward from the adsorption surface. Here, the edge of the micro LED transfer head 1000 is the outer part of the area of the micro LED transfer head 1000 corresponding to the area where the micro LED exists while the micro LED 100 is chipped on the upper surface of the first substrate 101. can mean

The shield unit 1100 is formed on the edge of the micro LED transfer head 1000, so that when the micro LED transfer head 1000 adsorbs the micro LED 100, external factors that interfere with the adsorption force are prevented. The lower end of ) blocks penetration into the transfer space 1300 formed while being spaced apart from the upper surface of the micro LED 100 of the first substrate 101 . In this case, the shield unit 1100 is made of an elastic material and can be sealed so that external factors that hinder the adsorption force do not flow into the transfer space 1300 . In addition, the shield part 1100 made of elastic material accommodates the transfer error due to the mechanical tolerance of the micro LED transfer head 1000, so that the micro LED transfer head 1000 and the upper surface of the micro LED 100 collide, causing the micro LED 100 to It can perform the function of a buffer so that it is not damaged.

The micro LED transfer head 1000 may use electrostatic force, suction force, magnetic force, van der Waals force, etc. to have an adsorption force for adsorbing the micro LED 100 . In this case, if foreign substances are adsorbed to the adsorption surface by electrostatic force, suction force, magnetic force, van der Waals force, etc. used by the micro LED transfer head 1000 to have adsorption force, the adsorption force that adsorbs the micro LED 100 may be hindered.

The micro LED transfer head 1000 of the present invention forms a shield part 1100 on the edge of the micro LED transfer head 1000 to transfer the micro LED 100 to the adsorption surface of the micro LED transfer head 1000. The transfer space 1300 is sealed as the 1100 contacts the upper surface of the support member 1200 . As a result, foreign matter adsorbed on the adsorption surface by the electrostatic force, suction force, magnetic force, van der Waals force, etc. used by the micro LED transfer head 1000 to have adsorption force is prevented from entering the transfer space 1300, and the transfer efficiency is improved. can be improved

When the micro LED transfer head 1000 adsorbs the micro LED 100 with electrostatic force using electrostatic force, the shield unit 1100 prevents factors that interfere with the electrostatic force of the micro LED transfer head 1000 inside the transfer space 1300. ingress can be prevented. An external factor that interferes with the electrostatic force of the micro LED transfer head 1000 using electrostatic force may be a charged foreign substance.

When the micro LED transfer head 1000 adsorbs the micro LED 100, if an external factor that interferes with the suction power is a charged foreign substance, the charged foreign substance is adsorbed on the adsorption surface where the micro LED 100 is to be adsorbed. (100) may cause a problem that is not adsorbed. Therefore, in the micro LED transfer head 1000 of the present invention, the shield part 1100 is formed on the edge so as to protrude downward from the adsorption surface, as shown in FIG. 3(b). When the micro LED transfer head 1000 descends to transfer the micro LED 100, the shield part 1100 may come into contact with the upper surface of the support member 1200. As a result, the transfer space 1300 is shielded, external factors such as charged foreign substances are prevented from entering the transfer space 1300, and factors that interfere with electrostatic force are blocked, thereby increasing transfer efficiency.

The micro LED transfer head 1000 may use a suction force. When the micro LED transfer head 1000 adsorbs the micro LED 100 by suction force using the suction force, the shield part 1100 is external factors such as outside air and foreign substances that hinder the suction force of the micro LED transfer head 1000. Inflow into the transfer space 1300 can be prevented.

For example, the micro LED transfer head 1000 may adsorb the micro LED 100 with a vacuum suction force by configuring an adsorption surface with a porous member having pores and applying a vacuum to the pores of the porous member. In this case, the upper part of the porous member is connected to a vacuum port for supplying a vacuum or releasing a vacuum, and a vacuum chamber for applying a vacuum to a plurality of pores of the porous member or releasing a vacuum applied to the pores according to the operation of the vacuum port is provided. can The structure coupling the vacuum chamber to the porous member is not limited thereto as long as it is suitable for preventing leakage of the vacuum to other parts when applying a vacuum to the porous member or releasing the applied vacuum.

The porous member is composed of a material containing a plurality of pores therein, and may be configured in the form of powder, thin film/thick film, and bulk having a porosity of about 0.2 to 0.95 in a regular arrangement or disordered pore structure. The pores of the porous member 1100 can be classified according to their size into micro pores with a diameter of 2 nm or less, meso pores with a diameter of 2 to 50 nm, and macro pores with a diameter of 50 nm or more. contains at least some The porous member 1100 can be classified into organic, inorganic (ceramic), metal, and hybrid porous materials according to their components.

The porous member includes an anodic oxide film in which pores are formed in a predetermined arrangement. The anodic oxide film means a film formed by anodic oxidation of a base metal, and the pore means a hole formed in the process of forming an anodic oxide film by anodic oxidation of a metal. For example, when the base metal is aluminum (Al) or an aluminum alloy, when the base metal is anodized, an anodic oxide film 1300 made of anodized aluminum oxide (Al ₂ O ₃ ) is formed on the surface of the base metal. As described above, the formed anodic oxide film is divided into a barrier layer in which pores are not formed and a porous layer in which pores are formed. The barrier layer is located on top of the base material, and the porous layer is located on top of the barrier layer. In this way, when the base material is removed from the base material on which the anodic oxide film having the barrier layer and the porous layer is formed, only the anodic oxide film made of anodized aluminum oxide (Al ₂ O ₃ ) remains.

The anodic oxide film has pores having a regular arrangement while being formed in a vertical shape with a uniform diameter. Therefore, when the barrier layer is removed, the pores have a structure vertically penetrating up and down, and through this, it is easy to form a vacuum pressure in a vertical direction.

The inside of the anodic oxide film can form an air flow path in a vertical form by means of vertical pores. The internal width of the pore has a size of several nm to several hundreds of nm. For example, when the size of the micro LED to be vacuum adsorbed is 30 μm x 30 μm and the internal width of the pores is several nm, the micro LED 100 can be vacuum adsorbed using approximately tens of millions of pores.

On the other hand, when the size of the micro LED 100 to be vacuum adsorbed is 30 μm x 30 μm and the internal width of the pores is several hundred nm, approximately tens of thousands of pores are used to vacuum adsorb the micro LED 100. do. In the case of the micro LED 100, the first semiconductor layer 102, the second semiconductor layer 104, the active layer 103 formed between the first semiconductor layer 102 and the second semiconductor layer 104, As it is composed of only the first contact electrode 106 and the second contact electrode 107, it is relatively light, so it is possible to perform vacuum adsorption using tens of thousands to tens of millions of pores of the anodic oxide film.

The porous member can be a powder, a coating film, or a bulk in terms of shape, and in the case of powder, various shapes such as a spherical shape, a hollow sphere shape, a fiber shape, and a tube shape are possible. It is also possible to manufacture and use shapes.

In addition, the porous member may include a dual structure of the first and second porous members. A second porous member is provided on top of the first porous member. The first porous member is a component that performs a function of vacuum adsorbing the micro LED 100, and the second porous member is positioned between the vacuum chamber and the first porous member to transfer the vacuum pressure of the vacuum chamber to the first porous member. perform a function

The first and second porous members may have different porosity characteristics. For example, the first and second porous members have different characteristics in terms of arrangement and size of pores, material of the porous member, and shape.

In terms of arrangement of pores, one of the first and second porous members may have a regular arrangement of pores, and the other may have a disordered arrangement of pores. In terms of pore size, any one of the first and second porous members may have a larger pore size than the other one. Here, the size of the pores may be an average size of pores or a maximum size among pores. In terms of the material of the porous member, if one is composed of one of organic, inorganic (ceramic), metal, and hybrid porous materials, the other is a material different from any one material, such as organic, inorganic (ceramic), It may be selected from among metals and hybrid porous materials. Looking at the shape of the porous member, the first and second porous members may have different shapes.

In this way, the function of the micro LED transfer head 1000 can be diversified by differentiating the arrangement, size, material and shape of the pores of the first and second porous members, and complementary to each of the first and second porous members. function can be performed. The number of porous members is not limited to two like the first and second porous members, and each porous member having a function complementary to each other is included in the scope of the embodiment.

When the pores of the porous member have a disordered pore structure, a plurality of pores are connected to each other inside the porous member to form an air flow path connecting the top and bottom of the porous member. On the other hand, when the pores of the porous member have a vertical pore structure, the inside of the porous member is penetrated through the upper and lower portions of the porous member by the vertical pores to form an air flow path.

When the first porous member is provided with an anodic oxide film having pores formed by anodizing a metal, the second porous member may be composed of a porous support having a function of supporting the first porous member. As long as the second porous member has a structure capable of supporting the first porous member, the material is not limited, and the structure of the porous member 1100 described above may be included. The second porous member may be formed of a rigid porous support having an effect of preventing central sagging of the first porous member. For example, the second porous member may be a porous ceramic material.

In the micro LED transfer head 1000, the suction surface of which is composed of a porous member having such pores, the shield portion 1100 is formed on the edge so as to protrude beyond the absorption surface, so that factors hindering the suction force of the micro LED transfer head 1000 are removed from the transfer space. (1300) to prevent inflow into the interior.

When the micro LED transfer head 1000, whose adsorption surface is composed of a porous member having pores, adsorbs the micro LED 100 with a suction force, external factors such as outside air and foreign substances that hinder the suction force are introduced into the transfer space, and the micro LED transfer head 1000 absorbs the micro LED 100. (100) May reduce suction power.

When the micro LED transfer head 1000 adsorbs the micro LED 100, if an external factor that hinders the suction power is external air, the external air may flow into the transfer space 1300 and cause a vortex. Due to this, a problem in that the micro LED 100 is not adsorbed to the adsorption surface may occur because the micro LED 100 is shaken.

In addition, when the micro LED transfer head 1000 adsorbs the micro LED 100, if an external factor that hinders the suction force is a foreign substance, the micro LED 100 is transferred to the adsorption surface of the porous member containing a lot of fine vacuum. In the process, foreign matter may stick to the adsorption surface and cause a problem of blocking pores. If the foreign matter blocks the pores of the porous member, it may interfere with the suction force for adsorbing the micro LED. In addition, if the foreign material blocks the pores of a partial region of the porous member, it may cause a problem that the adsorption force to the micro LED 100 in the corresponding partial region becomes non-uniform. Therefore, the micro LED transfer head 1000 of the present invention descends toward the upper surface of the micro LED 100 and is formed on the edge so as to protrude downward from the absorption surface of the micro LED transfer head 1000 when the micro LED 100 is transferred to the absorption surface. By contacting the upper surface of the support member 1200, the shield unit 1100 seals the transfer space 1300 and blocks external factors such as outside air and foreign substances that interfere with suction power from entering the transfer space 1300. . Due to this, the external air is blocked, so that the micro LED 100 can be effectively transferred to the adsorption surface without shaking of the micro LED due to the occurrence of vortex, and the inflow of foreign substances blocking the pores is prevented, so that the micro LED 100 is uniformly adsorbed. warrior can do it.

In addition, the micro LED transfer head 1000 may use magnetic force. When the micro LED transfer head 1000 adsorbs the micro LED 100 with magnetic force using magnetic force, the shield unit 1100 prevents factors that interfere with the magnetic force of the micro LED transfer head 1000, such as diamagnetic foreign substances. Inflow into the space 1300 may be prevented. When the micro LED transfer head 1000 adsorbs the micro LED 100 using magnetic force, the top surface of the micro LED 100 may be coated with a magnetic material.

When an external factor interfering with the magnetic force of the micro LED transfer head 1000 is a diamagnetic foreign material, the micro LED transfer head 1000 ) may cause a problem that the micro LED 100 is not adsorbed on the adsorption surface by interfering with the magnetic force. Therefore, in the micro LED transfer head 1000 of the present invention, the shield part 1100 is formed on the edge so as to protrude downward from the adsorption surface, so that the micro LED transfer head 1000 is formed as shown in FIG. 3(b). When descending to transfer, the shield unit 1100 contacts the upper surface of the support member 1200 to seal the transfer space 1300. As a result, external factors that interfere with magnetic force, such as foreign substances of the diamagnetic material, are prevented from being introduced into the transfer space 1300, and thus factors that interfere with magnetic force can be blocked.

The micro LED transfer head 1000 may use van der Waals force. When the micro LED transfer head 1000 adsorbs the micro LED 100 by the van der Waals force using the van der Waals force, factors that interfere with the van der Waals force of the micro LED transfer head 1000, such as foreign matter, are transferred. Inflow into the space 1300 may be prevented.

When the micro LED transfer head 1000 adsorbs the micro LED 100 using van der Waals force, if a foreign substance is a factor that hinders the adsorption force, the foreign substance flows into the transfer space 1300 and is adsorbed on the adsorption surface, thereby causing the micro LED transfer head 1000 to absorb the micro LED 100. The adsorption force for adsorbing the LED 100 may be hindered. Therefore, in the micro LED transfer head 1000 of the present invention, the shield part 1100 is formed on the edge so as to protrude downward from the adsorption surface so that the micro LED 100 is transferred to the adsorption surface and descends toward the upper surface of the micro LED 100. In this case, the shield part 1100 is allowed to come into contact with the upper surface of the support member 1200. As a result, while the transfer space 1300 is shielded, the transfer efficiency of the micro LED 100 can be increased by preventing external factors such as foreign substances that hinder the van der Waals force flowing into the transfer space 1300 from being introduced.

As shown in FIG. 3, the micro LED transfer system 1 according to the first embodiment of the present invention adsorbs the micro LED 100 with the adsorption surface and the shield unit 1100 formed on the rim so as to protrude downward from the adsorption surface. A micro LED transfer head 1000 including a ) is installed under the first substrate 101 on which the micro LED 100 is chipped and the first substrate 101 to support the first substrate 101. When the micro LED 100 of the first substrate 101 is transferred to the adsorption surface by descending in the direction of ), the shield unit 1100 contacts the upper surface of the support member 1200, so that the micro LED transfer head 1000 The transfer space 1300 formed while the lower end is spaced apart from the upper surface of the micro LED 100 of the first substrate 101 may be sealed. Due to this, when the micro LED transfer head 1000 adsorbs the micro LED 100, it is possible to increase the transfer efficiency by shielding external factors that interfere with the adsorption force from penetrating into the transfer space 1300.

In the micro LED transfer system 1 of the first embodiment shown in FIG. 3, the horizontal area of the first substrate 101 is smaller than the horizontal area of the upper surface of the support member 1200, but the first substrate 101 The horizontal area is formed to be the same as the upper surface of the support member 1200, so that when the micro LED transfer head 1000 descends in the direction of the upper surface of the micro LED, the shield unit 1100 may come into contact with the upper surface of the first substrate 101. there is. Accordingly, the shield unit 1100 may contact the support member 1200 or the upper surface of the first substrate 101 when the micro LED 100 of the first substrate 101 is transferred to the absorption surface. In addition, since the shield part 1100 is formed on the edge of the micro LED transfer head 1000 so as to protrude downward from the suction surface, the lower surface of the shield part 1100 is on the upper surface of the support member 1200 or the first substrate 101. can contact

The micro LED transfer system 1 of the second embodiment below is based on the configuration of the shield unit 1100 formed on the edge of the micro LED transfer head 1000 of the micro LED transfer system 1 of the first embodiment on a first substrate ( 101) is an embodiment in which the configuration is changed to be formed on the support member 1200 for supporting. Therefore, since the configuration of the micro LED transfer head 1000 using electrostatic force, suction force, magnetic force, and van der Waals force is the same, in the following description, external factors interfering with the suction force of electrostatic force, suction force, magnetic force, and van der Waals force are used in the transfer space. (1300) Only the characteristics of the shape formed on the support member 1200 of the shield portion 1100 that blocks penetration into the inside will be described.

Example 2

Hereinafter, a second embodiment of the present invention will be described. However, the embodiment described below will be described focusing on characteristic components compared to the first embodiment, and descriptions of components identical or similar to those of the first embodiment will be omitted.

The micro LED transfer system 1 according to the second embodiment is characterized in that the shield part 1100 formed on the edge of the micro LED transfer head 1000 of the first embodiment is formed on the support member 1200.

4 is a diagram showing a micro LED transfer system 1 according to a second preferred embodiment of the present invention. As shown in FIG. 4 , the micro LED transfer head 1000 constituting the micro LED transfer system 1 of the second embodiment is in a state before descending.

The micro LED transfer system 1 according to the second embodiment includes a micro LED transfer head 1000 for adsorbing the micro LED 100 with an adsorption surface, a first substrate 101 chipped with the micro LED 100, a first It is configured to include a support member 1200 for supporting the substrate 101 .

As shown in FIG. 4 , a shield part is formed on the edge of the support member 1200 to protrude upward from the support member 1200 or to protrude upward from the edge of the first substrate 101 to the upper portion of the first substrate 101 . (1100) is formed. Here, the edge of the support member 1200 may refer to an outer portion of the first substrate 101 installed on the upper surface of the support member 1200 . 4 showing the second embodiment, the horizontal area of the first substrate 101 is smaller than the horizontal area of the upper surface of the support member 1200, but the horizontal area of the first substrate 101 is the support member 1200 The shield unit 1100 may be formed in the same manner as the upper surface of the first substrate 101 so as to protrude upward from the edge of the first substrate 101 . When the shield unit 1100 is formed to protrude upward from the edge of the first substrate 101, the edge of the first substrate 101 has the micro LED 100 positioned on the upper surface of the first substrate 101. It can mean the outer part of the area.

When the micro LED transfer head 1000 descends toward the upper surface of the micro LED 100 to transfer the micro LED 100 of the first substrate 101 to the absorption surface, it protrudes upward from the rim of the support member 1200. The shield part 1100 formed to contact the lower edge of the micro LED transfer head 1000. Since the shield part 1100 is formed to protrude upward from the edge of the support member 1200, the upper surface of the shield part 1100 contacts the lower surface of the micro LED transfer head 1000. As a result, the transfer space 1300 formed while the lower end of the micro LED transfer head 1000 is spaced apart from the upper surface of the micro LED 100 of the first substrate 101 is sealed.

The shield part 1100 is formed to protrude upward from the rim of the support member 1200 or the first substrate 101, so that when the micro LED transfer head 1000 adsorbs the micro LED 100, the outer part interferes with the adsorption force. Factors are blocked from penetrating into the transcription space 1300. In this case, the shield unit 1100 is made of an elastic material and can be sealed so that external factors that hinder the adsorption force do not flow into the transfer space 1300 . In addition, the shield unit 1100 accommodates transfer errors due to mechanical tolerances of the micro LED transfer head 1000 so that the micro LED 100 is not damaged due to collision between the micro LED transfer head 1000 and the upper surface of the micro LED 100. It can act as a buffer to prevent

As described above, embodiments of the present invention have a shield unit 1100 so that external factors that hinder the adsorption force of the micro LED transfer head 1000 penetrate into the transfer space 1300 where the transfer of the micro LED 100 is performed. can block it Due to this, it is possible to prevent deterioration of the adsorption force by being adsorbed on the adsorption surface of the micro LED transfer head 1000 by external factors that hinder the adsorption force, and to improve the transfer efficiency.

As described above, although it has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify the present invention within the scope not departing from the spirit and scope of the present invention described in the claims below. Or it can be carried out by modifying.

1: Micro LED transfer system 1000: Micro LED transfer head
1100: shield part 1200: support member
1300: Transfer space 100: Micro LED
101: first substrate

Claims (15)

A micro LED transfer head including a shield portion formed on an edge to adsorb micro LEDs to an adsorption surface and protrude downward from the adsorption surface;
A first substrate chipped with micro LEDs; and
A support member installed below the first substrate to support the first substrate;
The micro LED transfer system, characterized in that the shield unit contacts the support member or the upper surface of the first substrate when transferring the micro LED of the first substrate to the suction surface.
According to claim 1,
Micro LED transfer system, characterized in that the shield portion is composed of an elastic material.
According to claim 1,
The micro LED transfer system, characterized in that the shield unit shields the micro LED transfer head from penetrating into the interior of the transfer space that interferes with the adsorption force when the micro LED transfer head adsorbs the micro LED.
According to claim 3,
The micro LED transfer head is a micro LED transfer head using electrostatic force,
The micro LED transfer system, characterized in that the shield unit prevents factors that interfere with the electrostatic force of the micro LED transfer head from entering into the transfer space when adsorbing the micro LED with the electrostatic force.
According to claim 3,
The micro LED transfer head is a micro LED transfer head using a suction force,
The micro LED transfer system, characterized in that, when the shield unit adsorbs the micro LED with the suction force, a factor obstructing the suction force of the micro LED transfer head is prevented from entering into the transfer space.
According to claim 3,
The micro LED transfer head is a micro LED transfer head using magnetic force,
The micro LED transfer system, characterized in that, when the shield unit adsorbs the micro LED with the magnetic force, a factor that interferes with the micro LED transfer head magnetic force is prevented from entering into the transfer space.
According to claim 3,
The micro LED transfer head is a micro LED transfer head using van der Waals force,
The micro LED transfer system, characterized in that, when the shield unit adsorbs the micro LED by the van der Waals force, prevents a factor obstructing the micro LED transfer head van der Waals force from entering into the transfer space.
delete According to claim 1,
The micro LED transfer system, characterized in that the transfer space is formed while the lower end of the micro LED transfer head is spaced apart from the upper surface of the micro LED of the first substrate.
delete a micro LED transfer head adsorbing the micro LED to the adsorption surface;
A first substrate chipped with micro LEDs;
a support member supporting the first substrate; and
A shield part formed on an edge of the support member to protrude upward from the support member or formed on an edge of the first substrate to protrude upward from the first substrate;
The micro LED transfer system, characterized in that in contact with the lower surface of the rim of the micro LED transfer head.
According to claim 11,
Micro LED transfer system, characterized in that the shield portion is composed of an elastic material.
delete According to claim 11,
The micro LED transfer system, characterized in that the transfer space is formed while the lower end of the micro LED transfer head is spaced apart from the upper surface of the micro LED of the first substrate.
According to claim 11,
The micro LED transfer system, characterized in that the shield unit shields the micro LED transfer head from penetrating into the transfer space by external factors that interfere with the adsorption force when the micro LED transfer head adsorbs the micro LED.

Images