KR102643764B1 - Transfer head for micro led - Google Patents

Abstract

The present invention relates to a micro LED transfer head that transfers micro LEDs from a first substrate to a second substrate. In particular, it relates to a micro LED transfer head that can transfer micro LEDs more efficiently by uniformizing the vacuum pressure in the adsorption area that adsorbs micro LEDs. This is about the LED transfer head.

Description

Micro LED transfer head {TRANSFER HEAD FOR MICRO LED}

The present invention relates to a micro LED transfer head that transfers micro LEDs from a first substrate to a second substrate.

In the current display market, LCD is still the mainstream, and OLED is rapidly replacing LCD and emerging as the mainstream. As display companies are rushing to participate in the OLED market, Micro LED (hereinafter referred to as ‘micro LED’) displays have recently emerged as another next-generation display. While the core materials of LCD and OLED are liquid crystal and organic materials, respectively, micro LED displays are displays that use LED chips themselves with a size of 1 to 100 micrometers (㎛) as the emitting material.

Since Cree applied for a patent for "Micro-Light Emitting Diode Array with Improved Light Extraction" in 1999 (Registration Patent Publication No. 0731673), and since the term micro LED appeared, related research papers have been published one after another, leading to research and development. This is being done. As a challenge to be solved in order to apply micro LED to displays, it is necessary to develop a customized microchip based on flexible materials/devices, and to transfer micrometer-sized LED chips and accurately apply them to display pixel electrodes. Technology for mounting is required.

In particular, in relation to the transfer of micro LED elements to the display substrate, as the size of LEDs decreases to 1 to 100 micrometers (㎛), existing pick and place equipment cannot be used. Transfer head technology that transfers with higher precision has become necessary. In relation to this transfer head technology, several structures have been proposed as discussed below, but each proposed technology has several disadvantages.

Luxvue, an American company, proposed a method of transferring micro LEDs using an electrostatic head (Public Patent Publication No. 2014-0112486, hereinafter referred to as ‘Prior Invention 1’). The transfer principle of prior invention 1 is the principle of generating adhesion to the micro LED through an electrification phenomenon by applying voltage to the head part made of silicon material. This method may cause problems with damage to the micro LED due to charging due to the voltage applied to the head during electrostatic induction.

The American company box). This method has no problems with LED damage compared to the electrostatic head method, but the adhesive force of the elastic transfer head must be greater than that of the target substrate during the transfer process to transfer the micro LED stably, and additional processes for forming electrodes are required. There is a downside. In addition, continuously maintaining the adhesion of the elastic polymer material also serves as a very important factor.

The Korea Institute of Photonics and Technology proposed a method of transferring micro LEDs using a ciliary adhesive structure head (Registered Patent Publication No. 1754528, hereinafter referred to as ‘Prior Invention 3’). However, prior invention 3 has the disadvantage that it is difficult to produce an adhesive structure of cilia.

The Korea Institute of Machinery and Materials proposed a method of transferring micro LEDs by coating adhesive on a roller (Registered Patent Publication No. 1757404, hereinafter referred to as ‘Prior Invention 4’). However, prior invention 4 requires continuous use of adhesive and has the disadvantage that the micro LED may be damaged when the roller is pressed.

Samsung Display proposed a method of transferring micro LEDs to the array substrate by electrostatic induction by applying 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- No. 2017-0026959, hereinafter referred to as ‘Prior Invention 5’). However, prior invention 5 has the disadvantage of requiring a separate solution and a drying process in that the micro LED is immersed in a solution and transferred to the array substrate.

LG Electronics proposed a method in which a head holder is placed between a plurality of pickup heads and a substrate, and its shape is deformed by the movement of the plurality of pickup heads to provide a degree of freedom to the plurality of pickup heads (Public Patent Publication No. 10) -2017-0024906, hereinafter referred to as ‘Prior Invention 6’). However, prior invention 6 has the disadvantage of requiring a separate process of applying the bonding material to the pickup heads in that it is a method of transferring micro LEDs by applying a bonding material with adhesive force to the adhesive surface of a plurality of pickup heads.

In order to solve the problems of the above prior inventions, it is necessary to improve the above-mentioned shortcomings while still adopting the basic principles adopted by the prior inventions. However, these shortcomings are derived from the basic principles adopted by the prior inventions, so the basic principles are maintained. However, there are limits to improving shortcomings. Accordingly, the applicant of the present invention does not stop at improving the shortcomings of the prior art, but proposes a new method that was not considered at all in the prior inventions.

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

Accordingly, the purpose of the present invention is to provide a micro LED transfer head that can increase the efficiency of micro LED transfer by uniformizing the vacuum pressure in the adsorption area that adsorbs the micro LED.

The micro LED transfer head according to one feature of the present invention is provided with a support part on the upper surface of the non-adsorption area that does not adsorb the micro LED, and forms a vacuum pressure in which the vacuum of the suction chamber is transmitted through the air passage formed between the support parts. It is characterized in that it includes an adsorption member to which the additional connection is made.

Additionally, a suction hole is formed in the vacuum pressure forming portion.

In addition, it is characterized in that it includes a porous member with pores coupled to the upper part of the adsorption member through the support part.

In addition, it is characterized in that it includes a support plate coupled to the upper part of the suction member through the support part and having a suction passage.

Additionally, the adsorption member is characterized as a porous adsorption member.

Additionally, the adsorption member is characterized as being a porous adsorption member with random pores.

Additionally, the adsorption member is characterized as a porous adsorption member having vertical pores.

Additionally, the adsorption member is characterized as being an anodic oxide film formed by anodizing a metal.

As seen above, the micro LED transfer head according to the present invention transfers the micro LED more efficiently by transmitting the vacuum pressure that generates the adsorption force for adsorbing the micro LED uniformly to the entire surface of the adsorption member that adsorbs the micro LED. There is an effect that can be done.

1 is a diagram illustrating a micro LED to be transported in embodiments of the present invention.
Figure 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 is a diagram showing a micro LED transfer head according to a preferred embodiment of the present invention.
Figure 4 is a view showing the suction member of the micro LED transfer head according to a preferred embodiment of the present invention as seen from above.
Figure 5 is a perspective view of a micro LED transfer head according to a preferred embodiment of the present invention.
Figure 6 is a diagram showing an adsorption member according to a modified example of the micro LED transfer head according to a preferred embodiment of the present invention as viewed from above.

The following merely illustrates the principles of the invention. Therefore, those skilled in the art will be able to invent various devices that embody the principles of the invention and are included in the concept and scope of the invention, although not clearly described or shown herein. In addition, all conditional terms and embodiments listed in this specification are, in principle, expressly intended only for the purpose of ensuring that the inventive concept is understood, and should be understood as not limiting to the embodiments and conditions specifically listed as such. .

The above-mentioned purpose, features and advantages will become clearer through the following detailed description in relation to the attached drawings, and accordingly, those skilled in the art in the technical field to which the invention pertains will be able to easily implement the technical idea of the invention. .

Embodiments described herein will be explained with reference to cross-sectional views and/or perspective views, which are ideal illustrations of the present invention. The thicknesses of films and regions and the diameters of holes shown in these drawings are exaggerated for effective explanation of technical content. The form of the illustration may be modified depending on manufacturing technology and/or tolerance. In addition, the number of micro LEDs shown in the drawing is only a partial number shown in the drawing as an example. Accordingly, embodiments of the present invention are not limited to the specific form shown, but also include changes in form produced according to the manufacturing process.

In describing various embodiments, components that perform the same function will be given the same names and same reference numbers for convenience even if the embodiments are different. In addition, the configuration and operation 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.

Figure 1 is a diagram showing a plurality of micro LEDs 100 to be transferred by the micro LED transfer head according to a preferred 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 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 Ga2O3.

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 are formed using a metal organic chemical vapor deposition (MOCVD) method, a chemical vapor deposition (CVD) method, or a plasma chemical vapor deposition method ( 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 with a composition formula of InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x+y≤1), such as GaN, AlN, AlGaN, InGaN, InN , InAlGaN, AlInN, etc., and may be doped with a p-type dopant such as Mg, Zn, Ca, Sr, Ba, etc.

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

However, the present invention is not limited to this, 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. As electrons and holes recombine, the active layer 103 transitions to a lower energy level and can generate light with a corresponding wavelength. For example, the active layer 103 may be formed of a semiconductor material having the composition formula InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x+y≤1), and may be formed as a single It can be formed as a quantum well structure or a multi quantum well structure (MQW: Multi Quantum Well). Additionally, it may include a quantum wire structure or a quantum dot structure.

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. First contact electrode 106 and/or 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 are cut using a laser, etc. along the cutting line or separated individually through an etching process, and the plurality of micro LEDs 100 are separated from the growth substrate 100 by a laser lift-off process. It can be made to be in a separable state from (101).

In Figure 1, ‘p’ refers to the pitch interval between micro LEDs 100, ‘s’ refers to the separation distance between micro LEDs 100, and ‘w’ refers to the width of the micro LEDs 100. 1 illustrates that the cross-sectional shape of the micro LED 100 is circular, but it is not limited to this and may have a cross-sectional shape other than a circular cross-section, such as a square cross-section, depending on the manufacturing method on the growth substrate 101. In the following drawings, the cross-sectional shape of the micro LED 100 is shown as a rectangular cross-section for convenience.

FIG. 2 is a diagram illustrating 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 to this, and may be made of a transparent plastic material and may be soluble. Plastic materials include insulating organic materials such as polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethyelenen napthalate (PEN), and polyethylene terephthalate (PET). polyethyeleneterepthalate, polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate: It may be an organic material selected from the group consisting of CAP).

In the case of a bottom-emitting type image that is implemented in the direction of the display substrate 301, the display substrate 301 must be made of a transparent material. However, in the case of a top-emission type in which an image is implemented in the opposite direction of 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 can be formed of metal.

When forming the display substrate 301 with metal, the display substrate 301 is one or more 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 to this.

The display substrate 301 may include a buffer layer 311. The buffer layer 311 can provide a flat surface and block foreign substances or moisture from penetrating. For example, the buffer layer 311 is made 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 acrylic. It may contain and may be formed as a laminate of a plurality of the exemplified materials.

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

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

The active layer 310 may include a semiconductor material, such as amorphous silicon or poly crystalline silicon. However, this embodiment is not limited to this and the active layer 310 may contain various materials. As an optional example, the active layer 310 may contain an organic semiconductor material, etc.

As another alternative embodiment, active layer 310 may contain an oxide semiconductor material. For example, the active layer 310 is made of group 12, 13, and 14 metal elements 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 film 313 serves to insulate the active layer 310 and the gate electrode 320. The gate insulating film 313 may be formed as a multi-layer or single-layer film made of an inorganic material such as silicon oxide and/or silicon nitride.

The gate electrode 320 is formed on top of the gate insulating film 313. The gate electrode 320 may be connected to a gate line (not shown) that applies 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), and magnesium (Mg), taking into account adhesion to adjacent layers, surface flatness of the stacked layer, and processability. , gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W) It can be formed as a single layer or multiple layers of one or more materials including copper (Cu).

An interlayer insulating film 315 is formed on the gate electrode 320. The interlayer insulating film 315 insulates the source electrode 330a, the drain electrode 330b, and the gate electrode 320. The interlayer insulating film 315 may be formed as a multi-layer or single-layer film made of an inorganic material. For example, the inorganic material may be a metal oxide or metal nitride. Specifically, the inorganic material may be silicon oxide (SiO2), silicon nitride (SiNx), silicon oxynitride (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), and tantalum. It may include oxide (Ta2O5), hafnium oxide (HfO2), or zinc oxide (ZrO2).

A source electrode 330a and a drain electrode 330b are formed on the interlayer insulating film 315. The source electrode 330a and the drain electrode 330b are made of 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), and copper (Cu) in a single or multilayer form. can be formed. The source electrode 330a and the drain electrode 330b are electrically connected to the source region and drain region of the active layer 310, respectively.

The planarization layer 317 is formed on a thin film transistor (TFT). The planarization layer 317 is formed to cover the thin film transistor (TFT), eliminating steps resulting from the thin film transistor (TFT) and flattening the top surface. The planarization layer 317 may be formed as a single-layer or multi-layer film made of an organic material. Organic materials include general purpose polymers such as Polymethylmethacrylate (PMMA) and Polystylene (PS), polymer derivatives with phenolic groups, acrylic polymers, imide polymers, aryl ether polymers, amide polymers, fluorine polymers, and p-xylene polymers. It may include polymers, vinyl alcohol-based polymers, and blends thereof. Additionally, the planarization layer 317 may be formed as a composite laminate of an inorganic insulating film and an organic insulating film.

The first electrode 510 is located on the planarization layer 317. The first electrode 510 may be electrically connected to a 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, the first electrode 510 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 will be accommodated. For example, the bank layer 400 may include 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, pixel density, etc. 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 to this, and the concave portion may have various cross-sectional shapes such as polygonal, rectangular, circular, conical, oval, and triangular shapes.

The bank layer 400 may further include a second bank layer 420 on top of the first bank layer 410. The first bank layer 410 and the second bank layer 420 have a step, and the width of the second bank layer 420 may be smaller than the width 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 arranged in a direction parallel to the data line or scan line, and is electrically connected to the second electrode 530. However, the present invention is not limited to this, 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 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 the wavelength range of 380 nm to 750 nm).

As an example, the first bank layer 410 and the second bank layer 420 are made of polycarbonate (PC), polyethylene terephthalate (PET), polyether sulfone, polyvinyl butyral, polyphenylene ether, polyamide, poly Etherimide, norbornene system resin, methacrylic resin, thermoplastic resin such as cyclic polyolefin system, epoxy resin, phenol resin, urethane resin, acrylic resin, vinyl ester resin, imide resin, urethane system 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. Insulating black matrix materials include organic resins, glass pastes and resins or pastes containing black pigments, metal particles such as nickel, aluminum, molybdenum and their alloys, metal oxide particles (e.g. chromium oxide), Or it may include metal nitride particles (for example, chromium nitride). In a modified example, the first bank layer 410 and the second bank layer 420 may be a distributed Bragg reflector (DBR) with 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 with wavelengths such as red, green, blue, and white, and white light can also be realized by using fluorescent materials or combining colors. Micro LED 100 has a size of 1 ㎛ to 100 ㎛. The micro LEDs 100 are individually or in plurality picked up on the growth substrate 101 by a transfer head according to an embodiment of the present invention and transferred to the display substrate 301, thereby forming a concave portion of the display substrate 301. can be accepted.

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 located on an opposite side 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 made of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, and compounds thereof, and a transparent or translucent electrode layer formed on the reflective film. The transparent or translucent electrode layer is made of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In2O3), and indium gallium oxide (IGO). It may include at least one selected from the group including indium gallium oxide (AZO) and aluminum zinc oxide (AZO).

Passivation layer 520 surrounds micro LED 100 within 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. That is not the case.

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

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 In2O3.

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

FIG. 3 shows a porous member 1100 and a suction chamber 1200 coupled to the upper part of the cross section A-A as seen from above the suction member 1400 of the micro LED transfer head 1000 according to the preferred embodiment of the present invention in FIG. 4. This is a cross-sectional view showing the structure of the micro LED transfer head 1000 according to a preferred embodiment of the present invention. The micro LED transfer head 1000 according to a preferred embodiment of the present invention includes an adsorption member 1400 that adsorbs the micro LED 100 with an adsorption surface, a porous member 1100 coupled to the upper part of the adsorption member 1400, It is configured to include a suction chamber 1200 that is coupled to the upper part of the porous member 1100 and applies a vacuum to the pores of the porous member 1100 to attach the micro LED 100 to the first substrate (e.g., the growth substrate 101). It is transferred to a second substrate (eg, display substrate 301).

The micro LED transfer head 1000 can adsorb or detach the micro LED 100 using suction force. In this case, the micro LED 100 may be adsorbed or detached from the adsorption member 1400 having an adsorption surface for adsorbing the micro LED 100.

The adsorption member 1400 may be a porous adsorption member. The adsorption member 1400 has an adsorption surface composed of a porous adsorption member with pores, and the micro LED 100 can be adsorbed using vacuum suction force by applying a vacuum to the pores of the adsorption member 1400. The adsorption member 1400 is composed of a porous adsorption member with pores, but may be composed of a porous adsorption member with arbitrary pores. When a porous adsorption member with random pores has a disordered pore structure, multiple pores inside the porous adsorption member are connected to each other to form an air flow path connecting the upper and lower sides of the porous adsorption member with random pores. Additionally, the adsorption member 1400 may be composed of a porous adsorption member having vertical pores. If the adsorption member 1400 is a porous adsorption member with vertical pores, vertical pores can be realized using laser, etching, etc. The interior of the porous adsorption member with vertical pores forms an air flow path as the vertical pores penetrate the upper and lower sides of the porous adsorption member.

The adsorption member 1400 may be an anodic oxide film formed by anodizing a metal. The anodic oxide film has pores formed in a certain arrangement. An anodic oxide film refers to a film formed by anodizing a base metal, and pores refer to holes formed in the process of anodizing a metal to form an anodizing film. For example, when the base metal is aluminum (Al) or an aluminum alloy, when the base material is anodized, an anodized aluminum oxide (Al ₂ O ₃ ) film is formed on the surface of the base material. The anodic oxide film formed in this way is divided into a barrier layer without pores formed inside and a porous layer with pores formed inside. 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 a base material on which an anodic oxide film having a barrier layer and a porous layer is formed on the surface, only an anodic oxide film made of anodized aluminum oxide (Al ₂ O ₃ ) remains.

The anodic oxide film has a uniform diameter, is formed in a vertical shape, and has pores with regular arrangement. Therefore, when the barrier layer is removed, a structure is obtained with pores penetrating vertically upward and downward, making it easy to form vacuum pressure in the vertical direction.

The interior of the anodic oxide film can form a vertical air flow path due to vertical pores. The internal width of the pores ranges from several nm to several hundred nm. For example, if 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. In the case of the micro LED 100, it basically 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 second semiconductor layer 104. Since 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 vacuum adsorb using tens to tens of millions of pores in the anodic oxide film.

The adsorption member 1400 may be made of metal, resin, semiconductor substrate (eg, silicon, sapphire), quartz, etc. in addition to the anodic oxide film, and may be implemented as a porous adsorption member having random or vertical pores.

The adsorption member 1400 includes an adsorption area that adsorbs the micro LED 100 and a non-adsorption area that does not adsorb the micro LED 100. The adsorption area is an area that adsorbs the micro LED 100 as the vacuum of the suction chamber 1200 is applied. The non-adsorption area is an area that does not adsorb the micro LED 100 because the vacuum of the suction chamber 1200 is not applied. Additionally, the suction member 1400 includes a vacuum pressure forming portion 10 formed on the upper surface of the suction member 1400 to which the vacuum of the suction chamber 1200 is transmitted. In the vacuum pressure forming unit 10, the vacuum applied from the suction chamber 1200 to the porous member 1100 is transmitted to form vacuum pressure, which generates an adsorption force in the adsorption area and adsorbs the micro LED 100. The micro LED 100 may be adsorbed to the adsorption area of the adsorption surface where adsorption force is generated due to the vacuum delivered to the vacuum pressure forming unit 10.

As shown in FIG. 3, a support portion 1300 is provided on the upper surface of the non-adsorption area that does not adsorb the micro LED 100. The support part 1300 is provided on the upper surface of the non-adsorbing area of the adsorption member 1400 and can support the load of the porous member 1100 and the suction chamber 1200, which will be described later, coupled to the upper part of the adsorption member 1400. .

Figure 4 is a view showing the suction member 1400 of the micro LED transfer head 1000 of the present invention as seen from above. In this case, the adsorption member 1400 is shown with the support part 1300, the vacuum pressure forming part 10, and the micro LED 100 enlarged for easy explanation. As shown in FIG. 4, the support portion 1300 is provided on the upper surface of the non-adsorption area of the suction member 1400, and the outer portion is formed continuously, and the inner side surrounded by the outer portion may be arranged in multiple columns and rows. . The inner support part 1300 may be formed in a cross shape by intersecting the support part 1300a in the column direction and the support part 1300b in the row direction. Here, the outer edge may refer to the upper surface of the suction member 1400 corresponding to the outer part of the micro LED presence area where the plurality of micro LEDs 100 vacuum-adsorbed to the suction surface of the suction member 1400 exist.

The support portion 1300 provided on the upper surface of the non-adsorption area has a continuous outline and can prevent external air from flowing into the adsorption area. As a result, factors that interfere with the formation of vacuum pressure in the vacuum pressure forming unit 10 can be blocked, and the adsorption force of the adsorption area generated by the vacuum pressure formed in the vacuum pressure forming unit 10 can be generated more effectively. do.

The inner support portions 1300 are arranged in a plurality of columns and rows, and a cross-shaped support portion 1300 can be formed by intersecting the column-direction support portions 1300a and the row-direction support portions 1300b. An air passage 30 may be formed between the outer support part 1300 and the inner cross-shaped support part 1300 and between the cross-shaped support parts 1300. The air passage 30 formed between the support parts 1300 connects the vacuum pressure forming part 10, through which the vacuum that generates the adsorption force to adsorb the micro LED 100, is transmitted, and forms the porous member 1100 from the suction chamber 1200. ) can be ensured that the applied vacuum is uniformly distributed in the vacuum pressure forming unit 10.

When the micro LED 100 is adsorbed to the adsorption surface of the adsorption member, a problem may occur in which the micro LED 100 is adsorbed to part of the adsorption surface and the micro LED 100 is not adsorbed to the other part. This is because the vacuum delivered from the suction chamber is concentrated on a portion of the adsorption member, creating an adsorption area in which no adsorption force is generated. The present invention forms an air passage 30 between the support parts 1300, so that the vacuum transmitted from the porous member 1100 having pores coupled to the upper part of the adsorption member 1400 through the support part 1300 is transmitted to the adsorption member ( 1400) so that it can be uniformly distributed to all vacuum pressure forming parts 10. As a result, the adsorption force of the entire adsorption surface of the adsorption member 1400 can be made uniform, and the transfer efficiency of the adsorption surface of the adsorption member 1400 to the micro LED 100 can be improved.

There is no limitation to the air passage 30 as long as it is located at a location where the vacuum pressure forming portions 10 can be connected to each other, but the support portion 1300 formed on the outer surface of the upper surface of the non-adsorbing area of the suction member 1400 is used to connect the vacuum pressure forming portions 10 to each other. Since it is continuously formed to prevent external air from flowing into the forming part 10, it may be desirable for the air passage 30 to be formed between the inner supports 1300 to connect the vacuum pressure forming part 10.

As shown in FIG. 4, a suction hole 20 may be formed in the vacuum pressure forming unit 10. The suction hole 20 is formed with an inner diameter smaller than the horizontal area of the top surface of the micro LED 100 to facilitate the formation of vacuum pressure that generates an adsorption force for adsorbing the micro LED 100 in the vacuum pressure forming unit 10. there is. Such a suction hole 20 may be formed with an inner diameter smaller than the horizontal area of the top surface of the micro LED 100, but is not limited thereto.

Figure 5 shows an adsorption member 1400 provided with a support part 1300 of the micro LED transfer head 1000 according to a preferred embodiment of the present invention, and a porous member coupled to the upper part of the adsorption member 1400 through the support part 1300. This is a perspective view of (1100) in a separated state. As shown in FIG. 5, the porous member 1100 is coupled to the upper part of the adsorption member 1400 through the support portion 1300.

The porous member 1100 having pores coupled to the upper part of the adsorption member 1400 through the support portion 1300 is composed of a material containing a large number of pores therein, and has a pore structure of a certain arrangement or disorder, with a pore size of 0.2 to 0.95. It can be composed of powder, thin/thick film, and bulk forms with a certain degree of porosity. The pores of the porous member 1100 can be divided 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, and these pores are Includes at least some The porous member 1100 can be classified into organic, inorganic (ceramic), metal, and hybrid porous materials depending on its components. Additionally, the porous member 1100 may be made of one of organic, inorganic (ceramic), metal, and hybrid porous materials.

In terms of shape, the porous member 1100 can be powder, coating film, or bulk. In the case of powder, various shapes such as spherical, hollow sphere, fiber, or tube are possible. In some cases, the powder is used as is, but it is used as a starting material. It is also possible to manufacture and use a coating film or bulk form.

The porous member 1100 may be composed of a porous member with random pores. When the porous member 1100 is composed of a porous member with random pores, it can be implemented by forming random pores through a laser or etching. Additionally, the porous member 1100 may be composed of a porous member having vertical pores. In this case, like random pores, it can be implemented through laser or etching.

When the pores of the porous member 1100 have a disordered pore structure, a plurality of pores inside the porous member 1100 are connected to each other to form an air flow path connecting the top and bottom of the porous member 1100. On the other hand, when the pores of the porous member 1100 have a vertical pore structure, the interior of the porous member 1100 is penetrated up and down the porous member 1100 by the vertical pores to form an air flow path. make it possible

The porous member 1100 is coupled to the upper part of the suction member 1400 through the support portion 1300 and is located between the suction member 1400 and the suction chamber 1200 to supply the vacuum of the suction chamber 1200 to the suction member 1400. It performs the function of transmitting to . In this case, as described above, since the air passage 30 is formed between the support parts 1300, the vacuum transmitted by the porous member 1100 coupled to the adsorption member 1400 through the support part 1300 is the air passage 30. It can be uniformly distributed throughout the vacuum pressure forming part 10. As a result, the vacuum transmitted from the porous member 1100 is prevented from being concentrated on only one vacuum pressure forming portion 10, and an adsorption force is generated in the adsorption area of all adsorption surfaces of the adsorption member 1400, and the micro LED 100 can be adsorbed.

The porous member 1100 may have a function of supporting the adsorption member 1400 like the support part 1300 when the adsorption member 1400 is a porous adsorption member with random pores or vertical pores or is provided with an anodic oxide film. You can. In this case, the porous member 1100 may be composed of a porous support. There is no limitation to the material of the porous member 1100 as long as it can achieve the function of supporting the adsorption member 1400, and the configuration of the porous member 1100 described above may be included. The porous member 1100 may be composed of a hard porous support that is effective in preventing the center of the adsorption member 1400 from sagging. For example, the porous member 1100 may be a porous ceramic material.

With this configuration, the micro LED 100 can be adsorbed with uniform adsorption force and the center of the adsorption member 1400 can be prevented from sagging.

Meanwhile, a support plate may be coupled to the upper part of the suction member 1400. Although not shown in the drawing, the support plate can be coupled to the upper part of the adsorption member 1400 through the support part 1300, just as the porous member 1100 is coupled to the upper part of the adsorption member 1400 through the support part 1300. there is. The support plate may be made of a non-porous material. For example, it may be made of a metal material.

A suction passage may be formed in the support plate made of a non-porous material. The suction passage is formed in a structure that penetrates the support plate vertically up and down, so that when the support plate is coupled to the upper part of the suction member 1400 through the support portion 1300, the vacuum applied from the suction chamber 1200 forms vacuum pressure. It can be delivered to the unit 10 to generate adsorption force in the adsorption member 1400. The suction passage may be formed in a structure that penetrates vertically up and down in the center of the support plate, but the position where the suction passage is formed is not limited to this. Additionally, a plurality of suction passages may be formed to transmit the vacuum of the suction chamber 1200. When the support plate is coupled to the upper part of the suction member 1400 through the support portion 1300, it can be effective in preventing the central sagging of the suction member 1400 by performing the function of supporting the suction member 1400, and can be effective in preventing the center of the suction member 1400 from sagging, and can be effective in preventing the center of the suction member 1400 from sagging. It is possible to perform the function of transmitting the vacuum of the suction chamber 1200.

Figure 6 is a view showing the adsorption member 1400 according to a modified example of the micro LED transfer head 1000 according to a preferred embodiment of the present invention as seen from above. The modified example differs from the embodiment in that the air passage 30 formed between the support portion 1300 provided on the upper surface of the non-adsorption area of the adsorption member 1400 is formed in a different shape from the air passage 30 of the embodiment. There is.

As shown in FIG. 6, in the modified example, a support portion 1300 is provided on the upper surface of the non-adsorption area that does not adsorb the micro LED 100. The support portion 1300 is provided on the upper surface of the non-adsorption area of the suction member 1400, and the outer portion may be formed continuously, and the inner portion surrounded by the outer edge may be arranged in a plurality of columns and rows. Here, the exterior may refer to the upper surface of the suction member 1400, which corresponds to the outer part of the micro LED presence area where a plurality of micro LEDs 100 vacuum-adsorbed to the suction surface of the suction member 1400 exist.

An air passage 30 may be formed between the outer support part 1300 and the inner support part 1300. Additionally, an air passage 30 may be interposed between the inner column support portion 1300a and the row support portion 1300b and between the row support portion 1300b and the row support portion 1300b located in the same row. The vacuum pressure forming portions 10 through which the vacuum of the suction chamber 1200 is transmitted through the air passage 30 may be connected to each other. The vacuum pressure forming units 10 connected to each other through the air passage 30 can ensure that the vacuum applied from the suction chamber 1200 to the porous member 1100 is uniformly distributed. As a result, a uniform adsorption force is generated throughout the adsorption area of the adsorption surface of the adsorption member 1400, thereby improving the transfer efficiency of the micro LED 100.

As described above, although the present invention has been described with reference to preferred embodiments, those skilled in the art may modify the present invention in various ways without departing from the spirit and scope of the present invention as set forth in the following patent claims. Or, it can be carried out in modification.

10: Vacuum pressure forming part 20: Suction hole
30: air passage 100: micro LED
1000: Micro LED transfer head 1100: Porous member
1200: suction chamber 1300: support
1300a: Column direction support 1300b: Row direction support
1400: Absorption member

Claims (8)

An adsorption member provided with a support part on the upper surface of the non-adsorption area that does not adsorb the micro LED, and connected to a vacuum pressure forming part through which the vacuum of the suction chamber is transmitted through an air passage formed between the supports; and
A porous member located between the suction member and the suction chamber, coupled to the upper part of the suction member through the support portion, and having pores,
The porous member,
A plurality of internal pores are connected to each other and the vacuum of the suction chamber is transmitted to the adsorption member through an air passage connecting the top and bottom of the porous member,
The support portion is provided on the upper surface of the non-adsorbing area of the suction member and has an outer perimeter that is continuously formed on the upper surface of the suction member to prevent external air from flowing into the vacuum pressure forming portion through which the vacuum of the suction chamber is transmitted. A micro LED transfer head characterized in that the inside surrounded by the outside is arranged in a plurality of columns and rows.
According to paragraph 1,
A micro LED transfer head, characterized in that a suction hole is formed in the vacuum pressure forming part.
delete According to paragraph 1,
A micro LED transfer head comprising a support plate coupled to an upper part of the suction member through the support portion and having a suction passage.
According to paragraph 1,
A micro LED transfer head, wherein the adsorption member is a porous adsorption member.
According to paragraph 1,
A micro LED transfer head, wherein the adsorption member is a porous adsorption member with random pores.
According to paragraph 1,
A micro LED transfer head, wherein the adsorption member is a porous adsorption member having vertical pores.
According to paragraph 1,
A micro LED transfer head, wherein the adsorption member is an anodized film formed by anodizing a metal.

Images