Light emitting device transferring apparatus and method of transferring light emitting devices using the same

Abstract

To provide a light emitting element transfer device capable of effectively transferring a light emitting element, and a transfer method using the same.SOLUTION: To provide a light-emitting element transfer device and a light-emitting element transfer method. The light emitting device transfer apparatus may include a first transfer head, a second transfer head disposed under the first transfer head, a stamp disposed under the second transfer head, a tilting adjustment member configured to adjust a tilting of the second transfer head, and a buffer member disposed adjacent to the stamp under the second transfer head, formed of an elastic material, and protruding downward from the stamp, wherein a thickness of the buffer member is greater than a sum of a thickness of the stamp and a thickness of the light emitting device.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a light-emitting element transferring device and a light-emitting element transferring method using the same. [Background technology]

[0002] Display devices have become increasingly important with the development of multimedia, and various types of display devices, such as organic light emitting displays (OLEDs) and liquid crystal displays (LCDs), are now being used.

[0003] Devices that display images on a display device include display panels such as light-emitting display panels and liquid crystal display panels. Among them, light-emitting display panels may include light-emitting diodes (LEDs), and light-emitting diodes include organic light-emitting diodes that use organic materials as fluorescent materials and inorganic light-emitting diodes that use inorganic materials as fluorescent materials.

[0004] In manufacturing display panels that use inorganic light-emitting diodes as light-emitting diodes, manufacturing equipment should be developed to arrange micro LEDs on the substrate of the display panel. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Korean Patent Publication No. 2020-0095909 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a light emitting element transferring device capable of effectively transferring light emitting elements, and a transferring method using the same.

[0007] The problems to be solved by the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0008] According to one embodiment of the present invention, a light-emitting element transfer device includes a first transport head, a second transport head disposed below the first transport head, a stamp disposed below the second transport head, a tilt adjustment member for adjusting the tilt of the second transport head, and a buffer member disposed below the second transport head adjacent to the stamp, made of an elastic material, and protruding below the stamp, wherein the thickness of the buffer member may be greater than the sum of the thickness of the stamp member and the thickness of the light-emitting element.

[0009] The light-emitting element transferring device may further include a gas flow path disposed in the second transport head and configured to supply gas to the buffer member, and a gas supply member configured to supply gas to the buffer member via the gas flow path.

[0010] The first transport head may have a cavity with an entrance facing downward, and the width of the entrance may be smaller than the width of the cavity.

[0011] The second transport head may be divided into a first part positioned within the cavity, a third part positioned outside the first transport head, and a second part positioned between the first part and the third part, and the width of the second part may be narrower than the widths of the first part and the third part.

[0012] The tilting adjustment member may include a first permanent magnet disposed on the first transport head, and a second permanent magnet disposed on the first portion of the second transport head, facing the first permanent magnet, and having a repulsive force with the first permanent magnet.

[0013] The second transport head has a chuck on one surface, and the stamp can be adsorbed by the chuck.

[0014] The second conveying head may be divided into a first part positioned within the cavity, a third part positioned outside the first conveying head, a second part positioned between the first part and the third part, and an inclined part positioned between the first part and the second part, and the width of the second part may be narrower than the widths of the first part and the third part.

[0015] The tilting adjustment member may include a plurality of second permanent magnets arranged on the first portion and the inclined portion, and a plurality of first permanent magnets arranged on the first conveying member to correspond to the plurality of second permanent magnets.

[0016] The light-emitting element transfer device may further include a pressure member that is disposed between the first transport head and the second transport head within the cavity of the first transport head and presses the second transport head downward.

[0017] The pressure member may be a spring.

[0018] The pressure member may include an elastic membrane disposed on the second transfer head within a cavity of the first transfer head, a gas pipe connected between the elastic membrane and the cavity, and a gas supply member that supplies gas to the gas pipe.

[0019] The first transport head, the second transport head and the tilting adjustment member may be air gyros.

[0020] A plurality of the buffer members may be arranged discontinuously around the stamp.

[0021] The buffer member may be disposed continuously around the stamp.

[0022] The buffer member may be a diaphragm.

[0023] The first transfer head includes a chuck disposed at a lower portion thereof, and the stamp can be attracted by the chuck.

[0024] The method for transferring the light-emitting element includes the steps of placing a transfer mechanism including a buffer member and a stamp on a substrate, lowering the transfer mechanism to bring the lower surface of the buffer member into contact with the substrate, adjusting the flatness of the transfer mechanism to match the flatness of the substrate, and applying pressure to the buffer member to bring the light-emitting element into contact with the substrate and transfer the light-emitting element, wherein the thickness of the buffer member is greater than the sum of the thicknesses of the stamp and the light-emitting element, the buffer member is made of an elastic material, and the thickness can be reduced by applying pressure to the buffer member.

[0025] In the step of placing the transfer mechanism on the substrate, the light-emitting element placed on the stamp may be aligned on the substrate based on a first alignment mark placed on one surface of the stamp and a second alignment mark placed on the substrate.

[0026] The transfer mechanism includes a first transport head, a second transport head disposed below the first transport head, and a tilting adjustment member that adjusts the tilting of the second transport head, and in the step of adjusting to match the flatness of the substrate, the tilting adjustment member can adjust the second transport head to match the flatness of the substrate while the second transport head is not in contact with the first transport head.

[0027] The transfer mechanism may further include a gas supply member that supplies gas to the buffer member and a gas flow path that is connected between the gas supply member and the buffer member, and may supply gas to the buffer member before the step of contacting the lower surface of the buffer member with the substrate. [Effects of the Invention]

[0028] According to an embodiment of the method for manufacturing a display panel, the stamp can ensure the relative flatness of the substrate without contacting the light emitting element with the substrate, thereby achieving high-precision alignment. This reduces defects in the light emitting element, thereby improving the product quality of the display panel and increasing the yield. This effect is particularly significant for large-area substrates.

[0029] The effects of the embodiments are not limited to the above examples, and a wider variety of effects are included in this specification. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a layout diagram illustrating a display device according to an embodiment. [Figure 2] FIG. 2 is an illustrative diagram showing an example of a pixel in FIG. 1. [Figure 3] FIG. 2 is an illustrative view showing still another example of the pixel of FIG. 1. [Figure 4] 3 is a cross-sectional view showing an example of a display panel taken along the line AA' in FIG. 2. FIG. [Figure 5] 1 is a schematic view showing a transfer apparatus LTD for a light-emitting element according to an embodiment. [Figure 6] FIG. 2 is a schematic diagram illustrating a transfer mechanism TDU according to one embodiment. [Figure 7] FIG. 10 is a plan view for explaining the number and shape of the buffer members. [Figure 8] FIG. 10 is a plan view for explaining the number and shape of the buffer members. [Figure 9] FIG. 10 is a plan view for explaining the number and shape of the buffer members. [Figure 10] FIG. 10 is a plan view for explaining the number and shape of the buffer members. [Figure 11] 10A and 10B are diagrams for explaining the operation of a light-emitting element transfer device that does not include a tilting adjustment member and a buffer member. [Figure 12] FIG. 10 is a schematic diagram illustrating a transfer mechanism for a light-emitting element according to another embodiment. [Figure 13] FIG. 10 is a schematic diagram illustrating a transfer mechanism for a light-emitting element according to another embodiment. [Figure 14] FIG. 10 is a schematic diagram illustrating a transfer mechanism for a light-emitting element according to another embodiment. [Figure 15] FIG. 10 is a schematic diagram illustrating a transfer mechanism for a light-emitting element according to another embodiment. [Figure 16]FIG. 10 is a schematic diagram illustrating a transfer mechanism for a light-emitting element according to another embodiment. [Figure 17] FIG. 10 is a schematic diagram illustrating a transfer mechanism for a light-emitting element according to another embodiment. [Figure 18] 1 is a flowchart illustrating a method for transferring a light-emitting element according to an embodiment. [Figure 19] 10A and 10B are cross-sectional views illustrating a method for transferring a light-emitting element. [Figure 20] 10A and 10B are cross-sectional views illustrating a method for transferring a light-emitting element. [Figure 21] 10A and 10B are cross-sectional views illustrating a method for transferring a light-emitting element. [Figure 22] 10A and 10B are cross-sectional views illustrating a method for transferring a light-emitting element. [Figure 23] 10A and 10B are cross-sectional views illustrating a method for transferring a light-emitting element.

[0031] 19 to 23 show cross-sectional views of the structure of the transfer device according to the transfer order of the light-emitting elements. DETAILED DESCRIPTION OF THE INVENTION

[0032] The advantages and features of the present invention, as well as methods for achieving them, will become clearer with reference to the following detailed embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and can be realized in various different forms. The present embodiments are provided solely for the purpose of complete disclosure of the present invention and to fully convey the scope of the invention to those skilled in the art to which the present invention pertains. The present invention is defined solely by the scope of the claims.

[0033] When an element or layer is referred to as being "on" another element or layer, this includes all cases where other layers or elements are directly on or between the other elements. The same reference numerals refer to the same components throughout the specification. The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments are merely examples, and the present invention is not limited to the details shown in the drawings.

[0034] Hereinafter, specific embodiments will be described with reference to the accompanying drawings.

[0035] Fig. 1 is a layout diagram illustrating a display device according to an embodiment, Fig. 2 is an exemplary diagram illustrating an example of a pixel of Fig. 1, and Fig. 3 is an exemplary diagram illustrating another example of the pixel of Fig. 1.

[0036] Referring to FIGS. 1 to 3, the display device is a device for displaying moving or still images, and can be used as a display screen for a variety of products, including portable electronic devices such as mobile phones, smartphones, tablet personal computers (PCs), smart watches, watch phones, mobile communication terminals, electronic organizers, e-books, portable multimedia players (PMPs), navigation systems, and ultra-mobile PCs (UMPCs), as well as televisions, notebook computers, monitors, billboards, and Internet of Things (IoT) devices.

[0037] The display panel 100 may be formed as a rectangular plane having a long side in a first direction DR1 and a short side in a second direction DR2 intersecting the first direction DR1. Corners where the long side in the first direction DR1 and the short side in the second direction DR2 intersect may be rounded or formed at a right angle to have a predetermined curvature. The planar shape of the display panel 100 is not limited to a rectangle and may be formed as other polygons, circles, or ellipses. The display panel 100 may be formed flat, but is not limited thereto. For example, the display panel 100 may include curved portions formed on the left and right sides, having a constant or variable curvature. In addition, the display panel 100 may be formed to be flexible so that it can be bent, warped, bent, folded, or rolled.

[0038] The display panel 100 may further include pixels PX, scan lines extending in a first direction DR1, and data lines extending in a second direction DR2 to display an image. The pixels PX may be arranged in a matrix in the first direction DR1 and the second direction DR2.

[0039] Each pixel PX may include multiple sub-pixels RP, GP, and BP as shown in Figures 2 and 3. Although Figures 2 and 3 show that each pixel PX includes three sub-pixels RP, GP, and BP, i.e., a first sub-pixel RP, a second sub-pixel GP, and a third sub-pixel BP, embodiments herein are not limited thereto.

[0040] The first sub-pixel RP, the second sub-pixel GP, and the third sub-pixel BP may be connected to any one of the data lines and at least one of the scan lines.

[0041] Each of the first subpixel RP, the second subpixel GP, and the third subpixel BP may have a rectangular, square, or diamond-shaped planar shape. For example, each of the first subpixel RP, the second subpixel GP, and the third subpixel BP may have a rectangular planar shape with a short side in the first direction DR1 and a long side in the second direction DR2, as shown in FIG. 2. Alternatively, each of the first subpixel RP, the second subpixel GP, and the third subpixel BP may have a square or diamond-shaped planar shape with sides having the same length in the first direction DR1 and the second direction DR2, as shown in FIG. 3.

[0042] 2, the first subpixel RP, the second subpixel GP, and the third subpixel BP may be arranged in the first direction DR1. Alternatively, one of the second subpixel GP and the third subpixel BP and the first subpixel RP may be arranged in the first direction DR1, and the remaining one and the first subpixel RP may be arranged in the second direction DR2. For example, as shown in FIG. 3, the first subpixel RP and the second subpixel GP may be arranged in the first direction DR1, and the first subpixel RP and the third subpixel BP may be arranged in the second direction DR2.

[0043] Alternatively, one of the first sub-pixel RP and the third sub-pixel BP and the second sub-pixel GP may be arranged in the first direction DR1, and the remaining one and the second sub-pixel GP may be arranged in the second direction DR2. Alternatively, one of the first sub-pixel RP and the second sub-pixel GP and the third sub-pixel BP may be arranged in the first direction DR1, and the remaining one and the third sub-pixel BP may be arranged in the second direction DR2.

[0044] The first sub-pixel RP may include a first light-emitting element that emits a first light, the second sub-pixel GP may include a second light-emitting element that emits a second light, and the third sub-pixel BP may include a third light-emitting element that emits a third light. Here, the first light may be light in the red wavelength band, the second light may be light in the green wavelength band, and the third light may be light in the blue wavelength band. The red wavelength band may be a wavelength band of approximately 600 nm to 750 nm, the green wavelength band may be a wavelength band of approximately 480 nm to 560 nm, and the blue wavelength band may be a wavelength band of approximately 370 nm to 460 nm, although embodiments of the present specification are not limited thereto.

[0045] Each of the first sub-pixel RP, the second sub-pixel GP, and the third sub-pixel BP may include an inorganic light-emitting element having an inorganic semiconductor as a light-emitting element that emits light. For example, the inorganic light-emitting element may be a flip-chip type micro LED (Light Emitting Diode), but the embodiment of the present specification is not limited thereto.

[0046] 2 and 3, the areas of the first subpixel RP, the second subpixel GP, and the third subpixel BP may be substantially the same, but embodiments herein are not limited thereto. At least one of the areas of the first subpixel RP, the second subpixel GP, and the third subpixel BP may be different from the others. Alternatively, two of the areas of the first subpixel RP, the second subpixel GP, and the third subpixel BP may be substantially the same, and the remaining one may be different from the two. Alternatively, the areas of the first subpixel RP, the second subpixel GP, and the third subpixel BP may be different from one another.

[0047] FIG. 4 is a cross-sectional view showing an example of a display panel taken along the line AA' in FIG.

[0048] 4, the display panel 100 may include a thin film transistor layer TFTL and a light emitting element LE disposed on a substrate SUB. The thin film transistor layer TFTL may be a layer in which a thin film transistor (TFT) is formed.

[0049] The thin film transistor layer TFTL includes an active layer ACT, a first gate layer GTL1, a second gate layer GTL2, a first data metal layer DTL1, a second data metal layer DTL2, a third data metal layer DTL3, and a fourth data metal layer DTL4, and also includes a buffer film BF, a gate insulating film 130, a first interlayer insulating film 141, a second interlayer insulating film 142, a first planarization film 160, a first insulating film 161, a second planarization film 180, and a second insulating film 181.

[0050] The substrate SUB may be a base substrate or a base member for supporting the display device. The substrate SUB may be a rigid substrate made of glass, but the embodiment of the present specification is not limited thereto. The substrate SUB may be a flexible substrate that allows bending, folding, rolling, etc. In this case, the substrate SUB may include an insulating material such as a polymer resin, such as polyimide (PI).

[0051] A buffer layer BF is disposed on one surface of the substrate SUB. The buffer layer BF may be a layer for preventing the penetration of air or moisture. The buffer layer BF may be composed of a plurality of inorganic layers alternately stacked. For example, the buffer layer BF may be formed as a multilayer structure in which one or more inorganic layers selected from the group consisting of silicon nitride, silicon oxynitride, silicon oxide, titanium oxide, and aluminum oxide are alternately stacked. The buffer layer BF may be omitted.

[0052] The active layer ACT is disposed on the buffer film BF. The active layer ACT may include a silicon semiconductor such as polycrystalline silicon, single-crystal silicon, low-temperature polycrystalline silicon, or amorphous silicon, or may include an oxide semiconductor.

[0053] The active layer ACT may include a channel TCH, a first electrode TS, and a second electrode TD of the thin film transistor TFT. The channel TCH of the thin film transistor TFT may be a region overlapping with the gate electrode TG of the thin film transistor TFT in a third direction DR3, which is the thickness direction of the substrate SUB. The first electrode TS of the thin film transistor TFT is disposed on one side of the channel TCH, and the second electrode TD is disposed on the other side of the channel TCH. The first electrode TS and the second electrode TD of the thin film transistor TFT may be regions that do not overlap with the gate electrode TG in the third direction DR3. The first electrode TS and the second electrode TD of the thin film transistor TFT may be regions that are conductive due to ions doped into a silicon semiconductor or an oxide semiconductor.

[0054] A gate insulating film 130 is disposed on the active layer ACT. The gate insulating film 130 may be formed of an inorganic film, for example, a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, a titanium oxide layer, or an aluminum oxide layer.

[0055] A first gate layer GTL1 is disposed on the gate insulating film 130. The first gate layer GTL1 may include a gate electrode TG of the thin film transistor TFT and a first capacitor electrode CAE1. The first gate layer GTL1 may be formed of a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0056] A first interlayer insulating film 141 is disposed on the first gate layer GTL1. The first interlayer insulating film 141 may be formed of an inorganic film, for example, a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, a titanium oxide layer, or an aluminum oxide layer.

[0057] A second gate layer GTL2 is disposed on the first interlayer insulating film 141. The second gate layer GTL2 may include a second capacitor electrode CAE2. The second gate layer GTL2 may be formed of a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0058] A second interlayer insulating film 142 is disposed on the second gate layer GTL2. The second interlayer insulating film 142 may be formed of an inorganic film, for example, a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, a titanium oxide layer, or an aluminum oxide layer.

[0059] A first data metal layer DTL1 including a first connection electrode CE1, a first subpad SPD1, and a data line DL is disposed on the second interlayer insulating film 142. The data line DL is formed integrally with the first subpad SPD1, but the embodiment of the present specification is not limited thereto. The first data metal layer DTL1 may be formed as a single layer or a multilayer made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0060] The first connection electrode CE1 can be connected to the first electrode TS or the second electrode TD of the thin film transistor TFT via a first contact hole CT1 that penetrates the first interlayer insulating film 141 and the second interlayer insulating film 142.

[0061] A first planarization film 160 for planarizing steps caused by the active layer ACT, the first gate layer GTL1, the second gate layer GTL2, and the first data metal layer DTL1 is disposed on the first data metal layer DTL1. The first planarization film 160 may be formed of an organic film such as an acrylic resin, an epoxy resin, a phenolic resin, a polyamide resin, or a polyimide resin.

[0062] A second data metal layer DTL2 is disposed on the first planarization layer 160. The second data metal layer DTL2 may include a second connection electrode CE2 and a second sub-pad PD2. The second connection electrode CE2 may be connected to the first connection electrode CE1 via a second contact hole CT2 that penetrates the first insulating layer 161 and the first planarization layer 160. The second data metal layer DTL2 may be formed of a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0063] A second planarization film 180 is disposed on the second data metal layer DTL2. The second planarization film 180 may be formed of an organic film such as an acrylic resin, an epoxy resin, a phenolic resin, a polyamide resin, or a polyimide resin.

[0064] A third data metal layer DTL3 is disposed on the second planarization film 180. The third data metal layer DTL3 may include a third connection electrode CE3 and a third subpad SPD3. The third connection electrode CE3 may be connected to the second connection electrode CE2 via a third contact hole CT3 penetrating the second insulating film 181 and the second planarization film 180. The third data metal layer DTL3 may be formed of a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0065] A third planarization film 190 is disposed on the third data metal layer DTL3. The third planarization film 190 may be formed of an organic film such as an acrylic resin, an epoxy resin, a phenolic resin, a polyamide resin, or a polyimide resin.

[0066] A fourth data metal layer DTL4 is disposed on the third planarization film 190. The fourth data metal layer DTL4 may include an anode pad electrode APD, a cathode pad electrode CPD, and a fourth sub-pad SPD. The anode pad electrode APD may be connected to the third connection electrode CE3 via a fourth contact hole CT4 penetrating the third insulating film 191 and the third planarization film 190. The cathode pad electrode CPD may be supplied with a first power supply voltage, which is a low potential voltage. The fourth data metal layer DTL4 may be formed of a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0067] Although the light emitting element LE is illustrated as a flip-chip micro LED in which the first contact electrode CTE1 and the second contact electrode CTE2 are arranged to face the anode pad electrode APD and the cathode pad electrode CPD, the light emitting element LE is not limited thereto. The light emitting element LE may be an inorganic light emitting element made of an inorganic material such as GaN. The light emitting element LE may have lengths in the first direction DR1, the second direction DR2, and the third direction DR3 of several to several hundred micrometers. For example, the light emitting element LE may have lengths in the first direction DR1, the second direction DR2, and the third direction DR3 of approximately 100 micrometers or less.

[0068] The light-emitting element LE can be formed by growing on a semiconductor substrate such as a silicon wafer. Each of the light-emitting elements LE can be transferred directly from the silicon wafer onto the anode pad electrode APD and the cathode pad electrode CPD of the substrate SUB. In this case, the first contact electrode CTE1 and the anode pad electrode APD can be bonded to each other by a bonding process. Also, the second contact electrode CTE2 and the cathode pad electrode CPD can be bonded to each other by a bonding process. The first contact electrode CTE1 and the anode pad electrode APD can be electrically connected to each other via a bonding electrode 23. Also, the second contact electrode CTE2 and the cathode pad electrode CPD can be electrically connected to each other via the bonding electrode 23.

[0069] As an example, a bonding electrode 23 is disposed on one surface of the light-emitting element LE. The bonding electrode 23 may be a bonded member formed by pressure fusion bonding using a laser. Here, pressure fusion bonding refers to a state in which the bonding electrode 23 is heated and melted to melt and mix the light-emitting element LE with the anode pad electrode APD and the cathode pad electrode CPD, and then cooled and solidified when the supply of the laser is stopped. Even when cooled and solidified in the melt-mixed state, the conductivity between the light-emitting element LE and the anode pad electrode APD and the cathode pad electrode CPD is maintained, thereby electrically and physically connecting the anode pad electrode APD and the cathode pad electrode CPD to the light-emitting element LE, respectively. Therefore, the bonding electrode 23 may be disposed on the first contact electrode CTE1 and the second contact electrode CTE2 of the light-emitting element LE.

[0070] The bonding electrode 23 may contain, for example, Au, AuSn, PdIn, InSn, NiSn, Au—Au, AgIn, AgSn, Al, Ag, or carbon nanotubes (CNTs), which may be used alone or in combination of two or more.

[0071] Each of the light emitting elements LE may be a light emitting structure including a base substrate SPUB, an n-type semiconductor NSEM, an active layer MQW, a p-type semiconductor PSEM, a first contact electrode CTE1, and a second contact electrode CTE2.

[0072] The base substrate SPUB may be a sapphire substrate, although embodiments herein are not limited thereto.

[0073] The n-type semiconductor NSEM is disposed on one surface of the base substrate SPUB. For example, the n-type semiconductor NSEM may be disposed on the bottom surface of the base substrate SPUB. The n-type semiconductor NSEM is made of GaN doped with an n-type conductivity dopant such as Si, Ge, or Sn.

[0074] The active layer MQW is disposed on a part of one surface of the n-type semiconductor NSEM.

[0075] The active layer MQW may include a material with a single or multiple quantum well structure. When the active layer MQW includes a material with a multiple quantum well structure, it may have a structure in which multiple well layers and barrier layers are alternately stacked. In this case, the well layers may be formed of InGaN, and the barrier layers may be formed of GaN or AlGaN, but are not limited to this. Alternatively, the active layer MQW may have a structure in which semiconductor materials with large band gap energy and semiconductor materials with small band gap energy are alternately stacked, and may include different Group III to Group V semiconductor materials depending on the wavelength band of the emitted light.

[0076] Although the present invention has been described with reference to a flip-chip type light emitting device, the present invention is not limited thereto, and a vertical type light emitting device may also be used.

[0077] FIG. 5 is a schematic view showing a transfer device for a light-emitting element (light-emitting element transfer device) LTD according to one embodiment.

[0078] The light-emitting element transfer apparatus LTD according to one embodiment is an apparatus used to transfer light-emitting elements.

[0079] As shown in FIG. 5, the transfer device LTD for the light emitting element includes a drive mechanism DU, a transfer mechanism TDU, a stage STG, and a controller CTU.

[0080] The drive mechanism DU enables the transfer mechanism TDU to move up, down, left, and right, and may include an XY drive unit DU-1 and a Z drive unit DU-2.

[0081] The XY drive unit DU-1 moves the transfer mechanism TDU above the stage STG on which the light emitting element LE is placed.

[0082] The Z driving unit DU-2 lowers the transfer mechanism TDU to approach the light emitting element LE, which is the pickup target, to a predetermined distance.

[0083] The transfer mechanism TDU is a device for picking up the light emitting element LE.

[0084] The transfer mechanism TDU may include, for example, any one of an electrostatic chuck, an adhesive chuck, a vacuum chuck, and a porous vacuum chuck. The transfer mechanism TDU can adsorb and lift the light-emitting element LE using the chuck. In the embodiment, an example is shown in which the light-emitting element LE is transferred to the substrate TS, but this is not limited thereto. The transfer mechanism TDU may be applied to so-called flip-chip mounting in which a flip chip is connected to bumps arranged in an array on the substrate TS, or may be applied to so-called die bonding in which the light-emitting element LE is bonded to the substrate TS.

[0085] The structure of the transfer mechanism TDU will be described in detail with reference to FIG.

[0086] The stage STG supports the substrate TS. The stage STG is installed in the center of the XY drive unit DU-1. The stage STG may be installed so as to be movable in the Y direction, but is not limited to this.

[0087] The controller CTU is connected to the drive mechanism DU and the transfer mechanism TDU and is configured to control the operation of these components to perform the processes required for transfer. The controller CTU is equipped with an interface (not shown) that transmits and receives signals between the drive mechanism DU, transfer mechanism TDU, and other components. The controller CTU is configured to provide feedback to the bonding process based on detection results from a camera, sensor, etc. For example, the controller CTU recognizes and detects the position of the marker on the substrate TS of the light-emitting element LE based on an image captured by the camera, and controls the XY drive unit DU-1 and Z drive unit DU-2 based on the detection results to perform control related to the transfer operation of aligning the position of the light-emitting element LE, etc.

[0088] Next, the configuration of the transfer mechanism TDU will be described.

[0089] FIG. 6 is a schematic diagram illustrating a transfer mechanism TDU according to one embodiment.

[0090] Referring to FIG. 6, the transfer mechanism TDU may include a first transport head 210, a second transport head 220, a stamp 230, a tilting adjustment member 240, and a buffer member 250.

[0091] The first transport head 210 is connected to the Z drive unit DU-2 and serves to support the second transport head 220.

[0092] The first transport head 210 has a cavity with an inlet facing downward, the width of which may be smaller than the width of the cavity.

[0093] The second transport head 220 is disposed below the first transport head 210 .

[0094] The second transfer head 220 is divided into a first section 220-a, a second section 220-b, and a third section 220-c. The first section 220-a is disposed within the cavity of the first transfer head 210, the third section 220-c is disposed outside the first transfer head 210, and the second section 220-b is disposed between the first section 220-a and the third section 220-c.

[0095] The second portion 220-b is formed with a width narrower than the first portion 220-a and the third portion 220-c, and the first portion 220-a is formed so as to overlap the cavity of the first transport head 210. The first portion 220-a can have a shape that follows the shape of the cavity of the first transport head 210. In the example of FIG. 6, the first transport head 210 has an entrance downward in the Z direction and a cavity that continues upward from the entrance. The cavity is formed inside the first transport head 210 and does not penetrate the first transport head 210. As shown in the cross-sectional view of FIG. 6, in the XY plane, the width of the entrance in the X direction is smaller than the width of the cavity in the X direction. As a result, the first transport head 210 is formed to be recessed inward in the cavity and to have a step. In the second transport head 220, the width of the first portion 220-a in the X direction is larger than the width of the second portion 220-b in the X direction. As a result, the second transport head 220 is formed to be recessed inward from the first portion 220-a to the second portion 220-b and to have a step. The second transport head 220 is fitted within the first transport head 210, with the step between the first section 220-a and the second section 220-b positioned to correspond to the step in the first transport head 210. The third section 220-c continues from the lower section of the second section 220-b downward in the Z direction to the outside of the first transport head 210. Therefore, in the second transport head 220, the third section 220-c mainly protrudes downward in the Z direction from the first transport head 210. In the example of FIG. 6, the first section 220-a and a portion of the second section 220-b of the second transport head 220 are formed to follow the shape of the cavity in the first transport head 210, and are formed to be slightly smaller than the cavity in the first transport head 210.

[0096] The second transfer head 220 may include one chuck 221, which may be an electrostatic chuck, an adhesive chuck, a vacuum chuck, or a porous vacuum chuck, on one surface. For example, the chuck 221 is disposed on one surface of the third section 220-c. The stamp 230 may be adsorbed to one surface of the second transfer head 220 by the chuck 221. In the example of FIG. 6, the third section 220-c has a recess facing downward, and the chuck 221 is fitted into this recess. The lower surface of the chuck 221 facing downward is configured to be able to adsorb the stamp 230. The lower surface of the chuck 221 is along the XY plane (horizontal plane).

[0097] The stamp 230 is disposed below the second transport head 220 .

[0098] The stamp 230 may include multiple layers. For example, the stamp 230 may include a base layer and a stamp layer. The base layer may extend along the XY plane (horizontal plane). The stamp layer may extend along the XY plane (horizontal plane).

[0099] The base layer supports the stamp layer and is made of, for example, polyethylene terephthalate (PET), polyurethane (PU), polyimide (PI), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polysulfone (PSF), polymethyl methacrylate (PMMA), triacetyl cellulose (TAC), cycloolefin polymer (COP), etc.

[0100] The stamp layer is disposed on one surface of the base layer. For example, the upper layer of the stamp 230 in the Z direction is the base layer, and the lower layer of the stamp 230 in the Z direction is the stamp layer, which is continuous with the lower surface of the base layer. The stamp layer includes multiple protrusions and can adhere or bond the light-emitting element LE. The stamp layer is made of an adhesive or sticky material, and examples of the adhesive material include OCA (Optical Clear Adhesive) and PSA (Pressure Sensitive Adhesive). Examples of the adhesive material include acrylic, urethane, and silicone adhesive materials. The multiple protrusions are formed on the stamp layer so as to protrude downward in the Z direction. One end surface of the multiple protrusions is flat, and the shape of the protrusion may be a polygonal pillar or a cylinder. For example, one end surface is an end surface facing downward in the Z direction, and the one end surface is along the XY plane (horizontal plane).

[0101] The tilt adjustment member 240 adjusts the tilt of the second transport head 220, thereby adjusting the relative flatness between the stamp 230 and the substrate TS.

[0102] The tilting adjustment member 240 may include a plurality of permanent magnets. The tilting adjustment member 240 may include a plurality of first permanent magnets 241 and a plurality of second permanent magnets 242. The plurality of first permanent magnets 241 are attached to the first transport head 210. The plurality of second permanent magnets 242 are attached to the second transport head 220. For example, the plurality of first permanent magnets 241 may be attached within recesses in the first transport head 210. In the example of FIG. 6 , recesses are provided at a plurality of locations facing the cavity of the first transport head 210. A first permanent magnet 241 is embedded in each recess in the first transport head 210. The plurality of second permanent magnets 242 may be attached to a first surface 220-a1, a second surface 220-a2, a third surface 220-a3, and a fourth surface 220a-4 of the first part 220-a of the second transport head 220. The first surface 220-a1 is the upper surface of the first portion 220-a along a horizontal plane. The second surface 220-a2 is a side surface that continues from the first surface 220-a1 and is perpendicular to the first surface 220-a1. The third surface 220-a3 is a surface that faces the second surface 220-a2, is a side surface that continues from the first surface 220-a1 and is perpendicular to the first surface 220-a1. The fourth surface 220a-4 is a surface of a portion of the first portion 220-a that forms a step with respect to the second portion 220-b, is a lower surface that continues from the second surface 220-a2 and the third surface 220-a3 and is perpendicular to the second surface 220-a2 and the third surface 220-a3. A recess is provided on each of the first surface 220-a1, the second surface 220-a2, the third surface 220-a3, and the fourth surface 220a-4, and a second permanent magnet 242 is embedded in each recess. The recesses of the first transport head 210 are arranged to correspond to the recesses of the second transport head 220. The number of first permanent magnets 241 and the number of second permanent magnets 242 are the same. In addition, a side surface extends from the fourth surface 220a-4 and is perpendicular to the fourth surface 220a-4 in the second transport head 220. The inner surface of the cavity of the first transport head 210 has side surfaces that follow the side surfaces extending from the first to fourth surfaces 220-a1 to 220-a4 and the fourth surface 220a-4.

[0103] The first permanent magnet 241 and the second permanent magnet 242 are arranged to face each other with the same polarities facing each other. For example, the S-polarity magnetic pole of the first permanent magnet 241 faces the S-polarity magnetic pole of the second permanent magnet 242. The attractive forces between the facing magnetic poles of the first permanent magnet 241 and the second permanent magnet 242 are balanced, and the second transport head 220 floats in the cavity of the first transport head 210 without contacting the first permanent magnet 241 and the second permanent magnet 242.

[0104] In Figure 6, a total of five pairs of first permanent magnets 241 and second permanent magnets 242 are arranged, but the number and positions of the first permanent magnets 241 and second permanent magnets 242 are not limited to this as long as the tilting of the second conveying head 220 can be adjusted using the tilting adjustment member 240.

[0105] In addition, even if an external force acts on the second transport head 220 and causes it to tilt, the magnetic force between the first permanent magnet 241 and the second permanent magnet 242 serves to return it to its original position when the external force is removed.

[0106] Since the second transfer head 220 is levitated due to the repulsive force between the first permanent magnet 241 and the second permanent magnet 242, the first transfer head 210 does not tilt even when the second transfer head 220 tilts. Conversely, the second transfer head 220 may tilt depending on the flatness of the substrate placed below.

[0107] The buffer member 250 is disposed around the stamp 230 on one surface (lower surface) of the second transfer head 220. The buffer member 250 may protrude below the stamp 230. For example, the thickness of the buffer member 250 may be greater than the sum of the thickness of the stamp 230 and the thickness of the light-emitting element LE. This allows the second transfer head 220 to first come into contact with the upper surface of the substrate TS when it descends. For example, as the second transfer head 220 descends, the buffer member 250 may first come into contact with the upper surface of the substrate TS.

[0108] The buffer member 250 may be made of an elastically deformable material. For example, the buffer member 250 may be formed of a silicon multilayer, a silicon-PET (polyethylene terephthalate) laminated layer, or the like. However, the buffer member 250 is not limited thereto. For example, the buffer member 250 may be a diaphragm.

[0109] The light emitting element transfer device LTD may further include a gas passage 255 and a gas supply member 260.

[0110] The gas flow path 255 is a flow path that supplies gas to the buffer member 250 , and is disposed in the second transfer head 220 .

[0111] The gas supply member 260 supplies gas to the buffer member 250 via the gas flow path 255 to inflate the buffer member 250. The buffer member 250 is formed, for example, to have a space therein, and the space is in communication with the gas flow path 255.

[0112] The gas supply member 260 supplies an inert or chemically inert gas, such as nitrogen (N), helium (He), neon (Ne), argon (Ar), carbon dioxide (CO), or a mixture thereof, to the internal space. Hereinafter, such an inert or chemically inert gas will be referred to as a neutral gas.

[0113] The gas supply member 260 may include a reservoir for storing gas, a gas pump for pressurizing and supplying the gas, a gas valve for regulating the flow of the gas, etc. The gas supply member 260 may also discharge the gas that inflates the buffer member 250 through a gas passage 255.

[0114] When the pressure inside the buffer member 250 is sufficiently high, the gas valve may be closed to stop the supply of gas and maintain the internal pressure of the buffer member 250. The gas valve may be, for example, but is not limited to, a ball valve, a globe valve, a gate valve, a control valve, or the like.

[0115] 7 to 10 are plan views for explaining the number and shape of the buffer members.

[0116] As can be seen from FIGS. 7 to 10, the number and shape of the buffer members can be modified in various ways.

[0117] 7 to 10, the stamp 230 follows the shape of the second transfer head 220. For example, if the second transfer head 220 is rectangular, the shape of the stamp 230 may also be rectangular, but is not limited thereto. For example, the second transfer head 220 and the stamp 230 may be circular.

[0118] The buffer member 250 is disposed around the stamp 230 on one surface of the second transport head 220. The buffer member 250 does not overlap the stamp 230.

[0119] 7 and 8, the plurality of cushioning members 250 may be circular.

[0120] For example, referring to FIG. 7(a), a plurality of buffer members 250 may be disposed at each of the four corners of the second transport head 220.

[0121] 7(b), a plurality of buffer members 250 may be disposed at the center of each side of the second transfer head 220. As shown in FIG.

[0122] 8(a), a plurality of buffer members 250 may be disposed at the four corners and the center of each side of the second transfer head 220, respectively.

[0123] 8(b), a plurality of buffer members 250 are arranged on each side of the second transport head 220 excluding the four corners of the second transport head 220. For example, three buffer members 250 may be arranged on each side.

[0124] 8(c), a plurality of buffer members 250 may be arranged at four corners of the second delivery head 220 and on each side of the second delivery head 220. The buffer members 250 may be arranged at equal intervals from each other, but are not limited to this.

[0125] Referring to FIG. 9, the plurality of buffer members 250 may be polygonal with corners.

[0126] 9(a), multiple buffer members 250 may be arranged to surround the corners of the stamp 230 at the four corners of the second transport head 220. For example, the buffer members 250 may be "L" shaped or inverted "L" shaped.

[0127] Referring to FIG. 9(b), the plurality of buffer members 250 may be rectangular and may be disposed at the center of each side of the second transfer head 220, respectively.

[0128] 9(c), the multiple buffer members 250 may have different shapes. For example, the multiple buffer members 250 may be arranged at the four corners of the second transfer head 220 so as to surround the corners of the stamp 230, and may further be arranged in the center of each side of the second transfer head 220 in a rectangular shape.

[0129] 7 and 9, it can be seen that the cushioning member 250 is disposed discontinuously around the periphery of the stamp 230.

[0130] 10, the buffer member 250 is disposed continuously around the stamp 230. For example, the buffer member 250 may be a single rectangular member surrounding the stamp 230 in the second transport head 220.

[0131] As can be seen from FIGS. 7 and 10, the number and shape of the buffer members can be modified in various ways.

[0132] FIG. 11 is a diagram for explaining the operation of a light emitting element transfer device that does not include a tilting adjustment member and a buffer member.

[0133] In a light emitting element transfer device that does not include a tilt adjustment member (240 in FIG. 6) and a buffer member (250 in FIG. 6), after the light emitting element LE attached to the stamp 230 contacts the surface of the substrate TS due to warping or tilting of the substrate TS, the stamp 230 may rotate. As a result, the rotation of the stamp 230 causes a change in the planar position of the light emitting element LE that first contacts the surface of the substrate TS. As a result, the light emitting element LE may fall over or become misaligned as a force acts on the surface of the substrate TS in the planar direction. For example, in a light emitting element transfer device that does not include a tilt adjustment member (240 in FIG. 6) and a buffer member (250 in FIG. 6), when transferring light emitting elements LE to the substrate TS, a plurality of light emitting elements LE that are adhered or bonded to the bottom surface of the stamp (230 in FIG. 6, included in the TDU in FIG. 11) are brought into contact with the top surface of the substrate TS. When the lower surface of the stamp and the upper surface of the substrate TS are generally parallel to each other (when the lower surfaces of the multiple light-emitting elements LE and the upper surface of the substrate TS are generally parallel to each other), the multiple light-emitting elements LE are pressed downward in the Z direction with a generally uniform pressure on the upper surface of the substrate TS, thereby allowing them to be positioned at desired positions on the substrate TS while preventing damage and misalignment. On the other hand, as described above, when the upper surface of the substrate TS is warped or tilted, and the lower surface of the stamp and the upper surface of the substrate TS are not generally parallel to each other (when the lower surfaces of the multiple light-emitting elements LE and the upper surface of the substrate TS are not generally parallel to each other), the stamp rotates due to the reaction force received from the substrate TS by the light-emitting element LE that first comes into contact with the substrate TS. In other words, the lower surface of the stamp (the planar direction described above) rotates so that it is aligned with the upper surface of the substrate TS. In this case, for example, the stamp rotates around the light-emitting element LE that first comes into contact with the substrate TS as the center point while mainly receiving the reaction force from the substrate TS. The pressing force is not applied evenly to the plurality of light-emitting elements LE, and the pressing force is applied unevenly, and the light-emitting elements LE that are primarily subjected to the uneven pressing force are damaged, misaligned, etc. In particular, in the case of a large-area substrate TS, the substrate TS is prone to warping and tilting, making the above problem more serious.

[0134] FIG. 12 is a schematic view showing a transfer mechanism for a light-emitting element according to another embodiment.

[0135] 12 differs from FIG. 6 in that a pressure member 270 is included between the first transfer head 210 and the second transfer head 220. The details described with reference to FIG. 6 can be applied to the configuration other than the pressure member 270, and the following description will focus on the pressure member 270.

[0136] The pressure member 270 is located in a recess in the first transport head 210 and is disposed between the first transport head 210 and the second transport head 220, so that it can apply pressure to the second transport head 220 while maintaining the space between the first transport head 210 and the second transport head 220. In the example of Fig. 12, the pressure member 270 is fitted across a recess formed on the upper surface of the inner surface of the cavity in the first transport head 210 and a recess formed on the upper surface facing the cavity in the second transport head 220. The pressure member 270 in Fig. 12 is capable of applying pressure to the second transport head 220 in the Z direction.

[0137] The pressure member 270 may include, but is not limited to, a spring. When the pressure member 270 is formed of a spring, it is possible to prevent a sudden pressure from being transmitted when a pressure is applied from the top to the bottom of the first transfer head 210.

[0138] In the embodiment, one pressure member 270 is disposed between the first transfer head 210 and the second transfer head 220, but the number of pressure members 270 is not limited. For example, a plurality of springs may be disposed between the first transfer head 210 and the second transfer head 220.

[0139] FIG. 13 is a schematic view showing a transfer mechanism for a light-emitting element according to another embodiment.

[0140] 13 differs from FIG. 6 in that a pressure member 270 is included between the first transfer head 210 and the second transfer head 220. The details described with reference to FIG. 6 can be applied to the configuration other than the pressure member 270, and the following description will focus on the pressure member 270.

[0141] The pressure member 270 is located in the cavity of the first transport head 210 and is disposed between the first transport head 210 and the second transport head 220 so as to maintain a space between the first transport head 210 and the second transport head 220. In the example of Fig. 13, a part of the pressure member 270 is supported on the upper surface of the inner surface of the cavity in the first transport head 210. The remaining part of the pressure member 270 extends towards the second transport head 220 and is formed so as to be able to come into contact with the upper surface of the second transport head 220. The pressure member 270 in Fig. 13 is capable of pressing the second transport head 220 in the Z direction.

[0142] In addition, the pressure member 270 may be a member for preventing sudden pressure transfer when pressure is applied from the top to the bottom of the first delivery head 210. The pressure member 270 may include, for example, a spring, but is not limited thereto.

[0143] In one embodiment, the pressure member 270 may include an elastic membrane 271 , a gas tube 272 and a gas supply member 273 .

[0144] The elastic membrane 271 is made of an elastic material such as an elastomer.

[0145] A space S may be provided between the elastic membrane 271 and the first transport head 210 .

[0146] The gas pipe 272 supplies gas to the space S between the elastic membrane 271 and the first transfer head 210, causing the elastic membrane 271 to expand downward. When the elastic membrane 271 expands, it pressurizes the second transfer head 220.

[0147] The gas supply member 273 supplies gas to the space S via the gas pipe 272. The gas supply member 273 controls the expansion force of the elastic membrane 271, thereby ultimately controlling the pressure applied to the second transfer head 220.

[0148] The gas supply member 273 supplies an inert or chemically inert gas, such as nitrogen (N), helium (He), neon (Ne), argon (Ar), carbon dioxide (CO), or a mixture thereof, to the internal space. Hereinafter, such an inert or chemically inert gas will be referred to as a neutral gas.

[0149] FIG. 14 is a schematic view showing a transfer mechanism for a light-emitting element according to another embodiment.

[0150] Referring to FIG. 14, the second conveying head 220 differs from FIG. 6 in that it further includes an inclined portion 220-ab between the first portion 220-a and the second portion 220-b, and that fewer tilting adjustment members 240 are arranged compared to FIG. 6.

[0151] The inclined portion 220-ab is disposed between the first portion 220-a having a first width Wa and the second portion 220-b having a second width Wb. The inclined portion 220-ab connects one end of the first portion 220-a to one end of the second portion 220-b, forming an inclination angle with a plane parallel to the first surface 220-a1 of the first portion 220-a. In the example of FIG. 14, the second transport head 220 is composed of, from top to bottom in the Z direction, the first portion 220-a, the inclined portion 220-ab, the second portion 220-b, and the third portion 220-c. As shown in FIG. 14, the width of the second portion 220-b in the X direction is smaller than the width of the first portion 220-a. The inclined portion 220-ab is positioned from the bottom end of the first portion 220-a to the top end of the second portion 220-b, connecting the first portion 220-a and the second portion 220-b. As shown in Fig. 14, the inclined portion 220-ab is formed so that its width in the X direction narrows from the top to the bottom in the Z direction. Furthermore, the cavity of the first transport head 210 is formed to have an inclined surface at the inclined portion 220-ab in accordance with the shape of the second transport head 220 in Fig. 14.

[0152] The tilting adjustment member 240 is disposed on the first surface 220-a1 and the inclined portion 220-ab of the second transport head 220, and may include a total of three pairs of first permanent magnets 241 and second permanent magnets 242. That is, as shown in Fig. 14, in the second transport head 220, the second permanent magnets 242 are disposed in recesses formed in the first surface 220-a1 and in recesses formed in the inclined surface of the inclined portion 220-ab. In addition, in the first transport head 210, the first permanent magnets 241 are disposed in recesses formed on the upper surface of the cavity, facing the recesses in the first surface 220-a1 and the recesses facing the recesses in the inclined surface of the inclined portion 220-ab.

[0153] FIG. 15 is a schematic view showing a transfer mechanism for a light-emitting element according to another embodiment.

[0154] 15 differs from FIG. 14 in that a pressure member 270 is included between the first transfer head 210 and the second transfer head 220. The details described with reference to FIG. 14 can be similarly applied to the configuration other than the pressure member 270, and the following description will focus on the pressure member 270.

[0155] The pressure applying member 270 has the same configuration and arrangement as in Figure 12, and is positioned across the recess of the first conveying head 210 and the recess of the second conveying head 220, and is arranged between the first conveying head 210 and the second conveying head 220, so that it can apply pressure to the second conveying head 220 while maintaining the space between the first conveying head 210 and the second conveying head 220.

[0156] The pressure member 270 may include, but is not limited to, a spring. When the pressure member 270 is formed of a spring, it is possible to prevent a sudden pressure from being transmitted when a pressure is applied from the top to the bottom of the first transfer head 210.

[0157] In the embodiment, one pressure member 270 is disposed between the first transfer head 210 and the second transfer head 220, but the number of pressure members 270 is not limited thereto.

[0158] FIG. 16 is a schematic view showing a transfer mechanism for a light-emitting element according to another embodiment.

[0159] 16 differs from FIG. 14 in that a pressure member 270 is included between the first transport head 210 and the second transport head 220. The details described with reference to FIG. 14 can be similarly applied to the configuration other than the pressure member 270, and the following description will focus on the pressure member 270.

[0160] The pressure member 270 is located in the cavity of the first transport head 210 and is disposed between the first transport head 210 and the second transport head 220 so as to maintain the space between the first transport head 210 and the second transport head 220. As in FIG. 13 , a portion of the pressure member 270 is supported by the first transport head 210, and the remaining portion is formed so as to be able to come into contact with the upper surface of the second transport head 220.

[0161] In addition, the pressure member 270 may be a member for preventing sudden pressure transfer when pressure is applied from the top to the bottom of the first delivery head 210. The pressure member 270 may include, for example, a spring, but is not limited thereto.

[0162] In one embodiment, the pressure member 270 may include an elastic membrane 271 , a gas tube 272 and a gas supply member 273 .

[0163] The elastic membrane 271 is made of an elastic material such as an elastomer.

[0164] A space S may be provided between the elastic membrane 271 and the first transport head 210 .

[0165] The gas pipe 272 supplies gas to the space S between the elastic membrane 271 and the first transfer head 210, causing the elastic membrane 271 to expand downward. When the elastic membrane 271 expands, it pressurizes the second transfer head 220.

[0166] The gas supply member 273 supplies gas to the space S via the gas pipe 272 .

[0167] The gas supply member 273 supplies an inert or chemically inert gas, such as nitrogen (N), helium (He), neon (Ne), argon (Ar), carbon dioxide (CO), or a mixture thereof, to the internal space. Hereinafter, such an inert or chemically inert gas will be referred to as a neutral gas.

[0168] FIG. 17 is a schematic view showing a transfer mechanism for a light-emitting element according to another embodiment.

[0169] Referring to FIG. 17, it differs from FIG. 14 in that the first transport head 210, the second transport head 220, and the tilting adjustment member 240 are formed of air gyros AG.

[0170] The air gyro AG can adjust the relative flatness between the stamp 230 and the substrate TS when the buffer member 250 contacts the substrate TS. The relative flatness between the stamp 230 and the substrate TS can be adjusted more precisely by the air gyro AG. The air gyro AG is configured, for example, to suck the second transfer head 220 toward the first transfer head 210 or to supply compressed air to the second transfer head 220 on the side away from the first transfer head 210, thereby adjusting the relative flatness between the stamp 230 and the substrate TS.

[0171] FIG. 18 is a flowchart showing a method for transferring light-emitting elements according to one embodiment. FIGS. 19 to 23 are cross-sectional views illustrating the method for transferring light-emitting elements. In FIGS. 19 to 23, cross-sectional views are shown of the structure of a transfer device according to the order in which light-emitting elements are transferred. In FIGS. 19 to 23, the transfer mechanism TDU and light-emitting elements LE are shown, which generally correspond to the cross-sectional views or plan views of the transfer mechanism TDU described with reference to FIGS. 6 to 10, respectively. Below, the method for transferring light-emitting elements shown in FIGS. 19 to 23 in addition to FIG. 18 will be described.

[0172] First, the transfer mechanism TDU is placed on the substrate TS (S110 in FIG. 18).

[0173] Referring to FIG. 19, a light emitting element LE and a first alignment mark AM1 are provided on the stamp 230 of the transfer mechanism TDU.

[0174] A second alignment mark AM2 is provided on the substrate TS.

[0175] The transfer mechanism TDU can be placed at a desired position by the XY drive unit DU-1 and Z drive unit DU-2 of the transfer device LTD for the light emitting element as explained in FIG.

[0176] For example, the transfer mechanism TDU can place the stamp 230 on the substrate TS by checking the first alignment mark AM1 and the second alignment mark AM2 placed on the stamp 230. For example, the transfer mechanism TDU is moved by the XY drive unit DU-1 so that the positions of the first alignment mark AM1 and the second alignment mark AM2 coincide with each other in the XY plane.

[0177] Next, the transfer mechanism TDU is lowered so that the lower surface of the buffer member 250 comes into contact with the substrate TS (S120 in FIG. 18).

[0178] For example, as shown in Fig. 20, the transfer mechanism TDU is lowered by the Z drive unit DU-2. If the substrate TS is tilted or warped, some of the buffer members 250-2 will come into contact with the substrate TS first. If the transfer mechanism TDU is then further lowered, the remaining buffer members 250-1 may come into contact with the substrate TS, as shown in Fig. 21.

[0179] Before contacting the lower surfaces of the buffer members 250-1 and 250-2 with the substrate TS, gas is supplied to the buffer members 250-1 and 250-2. The thickness of the buffer members 250-1 and 250-2 to which gas is supplied is greater than the sum of the thickness of the stamp 230 and the thickness of the light emitting element LE. Therefore, when the buffer members 250-1 and 250-2 are in contact with the substrate TS, the light emitting element LE does not contact the substrate TS.

[0180] Next, the tilt adjustment member 240 adjusts the flatness of the second transport head 220 to match the flatness of the substrate TS (S130 in FIG. 18).

[0181] For example, as shown in FIG. 20, if the substrate TS is tilted or warped, when the transfer mechanism TDU is lowered, some of the buffer members 250-2 will first come into contact with the substrate TS. Then, when the transfer mechanism TDU is further lowered, the remaining buffer member 250-1 may come into contact with the substrate TS, as shown in FIG. 21. As a result, as shown in FIG. 21, for example, the second transfer head 220 is positioned above the substrate TS while the light-emitting element LE remains out of contact with the substrate TS, with the lower surface of the second transfer head 220 (the lower surface of the stamp 230, the lower surface of the light-emitting element LE) and the upper surface of the substrate TS adjusted to be aligned with each other, i.e., with the relative flatness adjusted. This prevents the alignment of the light-emitting element LE while the relative flatness of the second transfer head 220 and the substrate TS is adjusted, ensuring high precision of the light-emitting element LE.

[0182] Next, the second transport head 220 is pressed to transfer the light emitting elements LE (S140 in FIG. 18).

[0183] For example, the transfer mechanism TDU can be further lowered by the Z drive unit DU-2, and the second transport head 220 can be further lowered to bring the light-emitting element LE into contact with the substrate TS, as shown in Fig. 22, thereby applying pressure to the buffer member 250. The buffer member 250 contracts due to the pressure applied, thereby bringing the light-emitting element LE into contact with the substrate TS.

[0184] The buffer member 250 reaches its maximum contracted length due to pressure and limits the lowering position of the light emitting element LE. Once the buffer member 250 reaches its maximum contracted length, it no longer contracts, thereby preventing excessive lowering of the second transfer head 220. The buffer member 250 can contract to its maximum contracted length while pressing and deforming the substrate TS. Because the lowering position is limited by the buffer member 250, damage to the light emitting element LE is prevented.

[0185] 23, the transfer mechanism TDU is lifted up to separate the light emitting element LE from the stamp 230. The second transport head 220 is returned to a predetermined position within the cavity in the first transport head 210 by the permanent magnets 241 and 242 that are the tilting adjustment member 240. In the above description, the tilt adjustment member 240 may include a permanent magnet. However, an electromagnet may be used instead of the permanent magnet. By adjusting the current and direction of the current supplied to the electromagnet, the tilt adjustment member 240 can adjust the tilt of the second transport head 220, thereby adjusting the relative flatness between the stamp 230 and the substrate TS. Alternatively, the tilt of the second transfer head 220 may be directly adjusted by power without using a magnet. For example, the tilt of the second transfer head 220 may be adjusted by a separate driving unit to adjust the relative flatness between the stamp 230 and the substrate TS.

[0186] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood that a person skilled in the relevant technical field or a person having ordinary knowledge in the relevant technical field can modify and change the present invention in various ways without departing from the spirit and technical scope of the present invention as set forth in the claims below.

[0187] Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims. [Explanation of symbols]

[0188] 100 Display Panel 10 Circuit Board TDU transcription mechanism 210 First transfer head 220 Second conveying head 230 stamps LE light-emitting element

Claims

1. First conveying head; a second transport head disposed below the first transport head; a stamp disposed below the second transport head; a tilting adjustment member for adjusting the tilting of the second transport head; and a buffer member disposed adjacent to the stamp below the second delivery head, made of an elastic material, and protruding below the stamp; The thickness of the buffer member is greater than the sum of the thickness of the stamp and the thickness of the light emitting element.

2. a gas flow path disposed in the second transfer head and supplying gas to the buffer member; and The light-emitting element transfer device according to claim 1 , further comprising a gas supply member that supplies gas to the buffer member through the gas flow path.

3. 2. The light-emitting element transfer device according to claim 1, wherein the first transfer head has a cavity with an inlet facing downward, the inlet having a width smaller than that of the cavity.

4. The light-emitting element transfer device described in claim 3, wherein the second conveying head is divided into a first part positioned within the cavity, a third part positioned outside the first conveying head, and a second part positioned between the first part and the third part, and the width of the second part is narrower than the widths of the first part and the third part.

5. 5. The light-emitting element transfer device of claim 4, wherein the tilting adjustment member includes a first permanent magnet arranged on the first transport head, and a second permanent magnet arranged on the first portion of the second transport head, facing the first permanent magnet, and having a repulsive force with the first permanent magnet.

6. 2. The light-emitting element transferring device according to claim 1, wherein the second transport head has a chuck on one surface thereof, and the chuck adsorbs the stamp.

7. The light-emitting element transfer device described in claim 3, wherein the second conveying head is divided into a first part positioned within the cavity, a third part positioned outside the first conveying head, a second part positioned between the first part and the third part, and an inclined part positioned between the first part and the second part, and the width of the second part is narrower than the widths of the first part and the third part.

8. 8. The light-emitting element transfer device of claim 7, wherein the tilting adjustment member includes a plurality of second permanent magnets arranged in the first portion and the inclined portion, and a plurality of first permanent magnets arranged on the first conveying member to correspond to the plurality of second permanent magnets.

9. 2. The light-emitting element transfer device according to claim 1, further comprising a pressure member disposed between the first and second transfer heads in the cavity of the first transfer head, and pressing the second transfer head downward.

10. 10. The light-emitting element transfer device according to claim 9, wherein the pressure member is a spring.

11. 10. The light-emitting element transfer device of claim 9, wherein the pressure member includes an elastic membrane disposed on the second conveying head within the cavity of the first conveying head, a gas pipe connected between the elastic membrane and the cavity, and a gas supply member that supplies gas to the gas pipe.

12. 2. The light-emitting element transfer device according to claim 1, wherein the first transport head, the second transport head, and the tilting adjustment member are air gyros.

13. The light-emitting element transferring device according to claim 1 , wherein a plurality of the buffer members are discontinuously arranged around the stamp.

14. The light-emitting element transferring device according to claim 1 , wherein the buffer member is disposed continuously around the stamp.

15. 2. The light-emitting element transfer device according to claim 1, wherein the buffer member is a diaphragm.

16. The light-emitting element transferring device according to claim 1 , wherein the first transfer head includes a chuck disposed at a lower portion thereof, and the stamp is attracted by the chuck.

17. placing a transfer mechanism including a buffer member and a stamp over a substrate; a thickness of the buffer member being greater than the sum of the thickness of the stamp and the thickness of the light emitting element, and lowering the transfer mechanism to bring the lower surface of the buffer member into contact with the substrate; adjusting the flatness of the transfer mechanism to the flatness of the substrate; and The buffer member is made of an elastic material, and when pressure is applied to the buffer member, the thickness of the buffer member becomes thin, and the buffer member is pressed to contact the light-emitting element to the substrate and transfer the light-emitting element.

18. In the step of disposing the transfer mechanism on a substrate, The method for transferring a light-emitting element according to claim 17 , further comprising aligning the light-emitting element disposed on the stamp onto the substrate based on a first alignment mark disposed on one surface of the stamp and a second alignment mark disposed on the substrate.

19. the transfer mechanism includes a first transport head, a second transport head disposed below the first transport head, and a tilting adjustment member that adjusts tilting of the second transport head; In the step of adjusting to the flatness of the substrate, The method of transferring a light-emitting element according to claim 17 , wherein the tilt adjustment member adjusts the second transfer head to match the flatness of the substrate while the second transfer head is not in contact with the first transfer head.

20. the transfer mechanism further includes a gas supply member that supplies gas to the buffer member, and a gas flow path that is connected between the gas supply member and the buffer member; The method of claim 17 , further comprising supplying a gas to the buffer member before contacting the lower surface of the buffer member with the substrate.

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