Stamp assembly, light emitting device transferring apparatus and transferring method thereof

Abstract

To provide a stamp assembly, a light-emitting element transfer device, and a light-emitting element transfer method, capable of improving product quality and yield of a display device in a transfer process by preventing a light-emitting element from remaining on a donor substrate or a stamp without being completely transferred in transfer.SOLUTION: The stamp assembly SA includes a stamp member 20 including a stamp layer 220 and a base layer 210, a magnetic plate 30 having a magnetic force on an upper surface of the base layer 210, and a plurality of magnetic beads MNB attachable to and detachable from the stamp layer 220 by the magnetic force of the magnetic plate 30.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a stamp assembly, a light-emitting element transfer device, and a transfer method thereof. [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 can 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] When manufacturing a display panel that uses inorganic light-emitting diodes as light-emitting diodes, a manufacturing device must be developed to place the micro LEDs on the substrate of the display panel. Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide a stamp assembly, a transfer apparatus and a transfer method that can solve the problem that the light emitting element remains on the donor substrate or on one side of the stamp during the light emitting element transfer process.

[0006] 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]

[0007] A stamp assembly according to one embodiment for solving the above problem may include a stamp member including a stamp layer and a base layer, a magnetic plate having a magnetic force on an upper surface of the base layer, and a plurality of magnetic beads that can be attached to and detached from the stamp layer by the magnetic force of the magnetic plate.

[0008] The magnetic beads may be ferromagnetic particles having a size of 10 nm or less.

[0009] The stamp layer may be divided into a first region where the magnetic beads are not disposed and a second region where the magnetic beads are disposed, and the first region may include a plurality of sub-regions.

[0010] The sub-regions may correspond to positions where light emitting elements are attached, and the area of ​​the sub-regions may be smaller than the area of ​​one surface of the light emitting elements.

[0011] The stamp layer may have elasticity and adhesiveness on one surface.

[0012] The magnetic plate can be an electromagnet or a permanent magnet.

[0013] According to one embodiment, a light-emitting element transfer device may include a stage for supporting a substrate, a stamp member including a stamp layer and a base layer, a first magnetic plate having a magnetic force on the upper surface of the base layer, a plurality of magnetic beads that can be attached to and detached from the stamp layer by the magnetic force of the first magnetic plate, and a second magnetic plate arranged below the stage and having a magnetic force.

[0014] The stamp layer may be divided into a first region where the magnetic beads are not disposed and a second region where the magnetic beads are disposed, and the first region may include a plurality of sub-regions.

[0015] The sub-regions may correspond to positions where light emitting elements are attached, and the area of ​​the sub-regions may be smaller than the area of ​​one surface of the light emitting elements.

[0016] The substrate may include at least one of a donor substrate on which light emitting devices are disposed and a target substrate to which the light emitting devices are transferred from the donor substrate.

[0017] The stamp layer may have elasticity and adhesiveness on one surface.

[0018] The first and second magnetic plates may be either electromagnets or permanent magnets.

[0019] A method for transferring a light-emitting element according to one embodiment may include the steps of arranging a plurality of magnetic beads on one surface of a stamp member, placing the stamp member on a donor substrate so that the plurality of magnetic beads face the light-emitting element on the donor substrate, lifting the light-emitting element with the stamp member, placing the stamp member on a target substrate so that the light-emitting element faces the target substrate, placing a first magnetic plate below the target substrate and transferring the light-emitting element and the plurality of magnetic beads to the target substrate, and placing a second magnetic plate on the upper surface of the stamp member and collecting the plurality of magnetic beads.

[0020] In the step of lifting the light emitting device with the stamp member, the stamp member may include a stamp layer having adhesive strength on one surface, and may press the light emitting device to adhere to the stamp layer, thereby lifting the light emitting device.

[0021] The stamp layer may be divided into a first region where the magnetic beads are not arranged and a second region where the magnetic beads are arranged, and the first region may include multiple sub-regions, each of which corresponds to a position where the light-emitting element is attached, and the area of ​​the sub-region may be smaller than the area of ​​one side of the light-emitting element.

[0022] When the stamp member contacts the light-emitting element, the magnetic beads are arranged in the second region, and some of the magnetic beads surrounding the sub-region are arranged on the upper surface of the light-emitting element, and are embedded inside the stamp layer of the stamp member by pressing the stamp member, so that one side of the light-emitting element can adhere to the stamp layer.

[0023] The step of placing a first magnetic plate below the target substrate and transferring the light-emitting element and a plurality of magnetic beads to the target substrate may include placing a first magnetic plate below the target substrate, pulling the magnetic beads placed on one side of the stamp member downward using the magnetic force of the first magnetic plate, and pressing the light-emitting element downward against the magnetic beads overlapping the top of the light-emitting element.

[0024] The first magnetic plate is a permanent magnet, and when placed in close proximity to the bottom of the target substrate, it can exert a magnetic force on the magnetic beads.

[0025] The first magnetic plate is an electromagnet, and is fixed to the bottom of a stage on which the target substrate is placed, and can exert a magnetic force on the magnetic beads by applying a current thereto.

[0026] In the step of placing a second magnetic plate on the upper surface of the stamp member and collecting the plurality of magnetic beads, by placing the second magnetic plate on the upper surface of the stamp member, an attractive force is generated between the second magnetic plate and the plurality of magnetic beads, and the plurality of magnetic beads can be moved from the top of the target substrate and the light-emitting element to one side of the stamp member. [Effects of the Invention]

[0027] According to one embodiment, the problem of light-emitting elements remaining on the donor substrate or stamp due to incomplete transfer can be solved by using magnetic beads to pick up the light-emitting elements, thereby improving the product quality and yield of the display device during the transfer process.

[0028] Furthermore, repair and stamp cleaning steps are no longer necessary, which reduces equipment costs and process costs.

[0029] The effects of the embodiments are not limited to the above-mentioned 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] FIG. 1 is a side view illustrating a structure of a stamp assembly according to one embodiment. [Figure 6] 1 is a front view showing a plurality of magnetic beads disposed on one surface of a stamp member according to one embodiment. [Figure 7] FIG. 1 is a side view illustrating a structure of a stamp assembly according to one embodiment. [Figure 8] 1 is a diagram showing a light-emitting element transfer device according to an embodiment; [Figure 9] 1 is a flowchart illustrating a method for transferring a light-emitting element according to an embodiment. [Figure 10] 10A to 10C are cross-sectional views illustrating a method for transferring a light emitting device according to another embodiment. [Figure 11] 10A to 10C are cross-sectional views illustrating a method for transferring a light emitting device according to another embodiment. [Figure 12] 10A to 10C are cross-sectional views illustrating a method for transferring a light emitting device according to another embodiment. [Figure 13] 10A to 10C are cross-sectional views illustrating a method for transferring a light emitting device according to another embodiment. [Figure 14]10A to 10C are cross-sectional views illustrating a method for transferring a light emitting device according to another embodiment. [Figure 15] 10A to 10C are cross-sectional views illustrating a method for transferring a light emitting device according to another embodiment. [Figure 16] 10A to 10C are cross-sectional views illustrating a method for transferring a light emitting device according to another embodiment. [Figure 17] 10A to 10C are cross-sectional views illustrating a method for transferring a light emitting device according to another embodiment. [Figure 18] 10A to 10C are cross-sectional views illustrating a method for transferring a light emitting device according to another embodiment. [Figure 19] 10A to 10C are cross-sectional views illustrating a method for transferring a light emitting device according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] 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.

[0032] 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 illustrated matters.

[0033] Hereinafter, specific embodiments will be described with reference to the accompanying drawings.

[0034] 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.

[0035] Referring to FIGS. 1 to 3, the display device is a device that displays moving images 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).

[0036] 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. The 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 curvature or a variable curvature. In addition, the display panel 100 may be formed to be flexible so that it can be bent, warped, folded, folded, or rolled.

[0037] 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 are arranged in a matrix in the first direction DR1 and the second direction DR2.

[0038] 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., the first sub-pixel RP, the second sub-pixel GP, and the third sub-pixel BP, the embodiments herein are not limited thereto.

[0039] 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.

[0040] 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.

[0041] 2, the first subpixel RP, the second subpixel GP, and the third subpixel BP may be arranged in a 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 a 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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, any 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.

[0046] FIG. 4 is a cross-sectional view showing an example of a display panel taken along the line AA' in FIG.

[0047] 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.

[0048] 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.

[0049] 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).

[0050] 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 include a plurality of inorganic layers stacked alternately. 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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 including any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0055] 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.

[0056] 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 including any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0057] 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.

[0058] 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 including any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0059] The first connection electrode CE1 may be connected to the first electrode TS or the second electrode TD of the thin film transistor TFT through a first contact hole CT1 that penetrates the first interlayer insulating film 141 and the second interlayer insulating film 142.

[0060] 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.

[0061] 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 including any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0062] 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.

[0063] 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 including any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0064] 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.

[0065] 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 including any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0066] A transparent conductive layer TCO may be disposed on each of the anode pad electrode APD and the cathode pad electrode CPD to enhance adhesion to the first contact electrode CTE1 and the second contact electrode CTE2 of the light emitting element LE. The transparent conductive layer TCO may be formed of a transparent conductive oxide such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). In other embodiments, the transparent conductive layer TCO may be omitted.

[0067] A protective film PVX may be disposed on the anode pad electrode APD, the cathode pad electrode CPD, and the first pad PD1. The protective film PVX is disposed to cover the edges of the anode pad electrode APD, the cathode pad electrode CPD, and the first pad PD1. The protective film PVX may be formed of an inorganic film, such as a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, a titanium oxide layer, or an aluminum oxide layer. In other embodiments, the protective film PVX may be omitted.

[0068] 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 to this. The light emitting element LE may be an inorganic light emitting element containing an inorganic material such as GaN. The light emitting element LE may have a length in the first direction DR1, a length in the second direction DR2, and a length in the third direction DR3 of several to several hundred micrometers. For example, the light emitting element LE may have a length in the first direction DR1, a length in the second direction DR2, and a length in the third direction DR3 of approximately 100 micrometers or less.

[0069] The light-emitting element LE is grown and formed on a semiconductor substrate such as a silicon wafer. Each light-emitting element LE can be directly transferred 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 a bonding electrode 23.

[0070] 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 product obtained 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.

[0071] The bonding electrode 23 may include, for example, Au, AuSn, PdIn, InSn, NiSn, Au-Au, AgIn, AgSn, Al, Ag, or carbon nanotubes (CNTs). These may be used alone or in combination of two or more. Depending on the type of bonding electrode 23, the bonding electrode 23 may be formed on the pad electrode by deposition or by various methods such as screen printing.

[0072] Alternatively, each of the light emitting elements LE can be transferred onto the anode pad electrode APD and the cathode pad electrode CPD of the substrate SUB using a transfer member, as will be described later with reference to FIGS.

[0073] 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.

[0074] The base substrate SPUB may be a sapphire substrate, although embodiments herein are not limited thereto.

[0075] The n-type semiconductor NSEM is disposed on one surface of the base substrate SPUB. For example, the n-type semiconductor NSEM is disposed on the bottom surface of the base substrate SPUB. The n-type semiconductor NSEM includes GaN doped with an n-type conductivity dopant such as Si, Ge, or Sn.

[0076] The MQW active layer is disposed on a portion of one surface of the n-type semiconductor NSEM. The MQW active layer may include a material with a single or multiple quantum well structure. When the MQW active layer 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 are formed of InGaN, and the barrier layers are formed of GaN or AlGaN, but are not limited to this. Alternatively, the MQW active layer 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.

[0077] In one embodiment, a flip-chip type light-emitting element is exemplified in which the first contact electrode CTE1 and the second contact electrode CTE2 are arranged on one side of the light-emitting element LE, but this is not limited to this and the light-emitting element may also be a vertical type light-emitting element in which the first contact electrode CTE1 and the second contact electrode CTE2 are arranged on both ends of the light-emitting element LE.

[0078] Figure 5 is a side view showing the structure of a stamp assembly according to an embodiment, Figure 6 is a front view showing a plurality of magnetic beads arranged on one surface of a stamp member according to an embodiment, and Figure 7 is a side view showing the structure of a stamp assembly according to an embodiment.

[0079] 5 and 6, the stamp assembly SA may include a stamp member 20, a magnetic plate 30 and a plurality of magnetic beads MNB.

[0080] The stamp member 20 is made of a laser-transmitting material and includes a base layer 210 and a stamp layer 220 disposed on one surface of the base layer 210 .

[0081] The base layer 210 may be made of, for example, glass or plastic. When the base layer 210 includes thin glass, the glass may be ultra-thin glass. Alternatively, the base layer 210 may include polyethylene terephthalate (PET), polyurethane (PU), polyimide (PI), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polysulfone (PSF), polymethyl methacrylate (PMMA), triacetyl cellulose (TAC), cycloolefin polymer (COP), or the like.

[0082] The stamp layer 220 may include, but is not limited to, acrylic, urethane, and silicone based materials.

[0083] The stamp layer 220 has elasticity and may have adhesiveness on one side.

[0084] The magnetic beads MNB are ferromagnetic particles, generally around 10 nm in size, with a uniform particle distribution. Each magnetic bead must have a high saturation magnetization and magnetic susceptibility to avoid aggregation and respond sensitively to changes in the external induced magnetic field.

[0085] In one embodiment, a plurality of magnetic beads MNB are disposed on one surface of the stamp layer 220. The plurality of magnetic beads MNB may not aggregate with each other on one surface of the stamp layer 220 and may be arranged in a single layer.

[0086] One surface of the stamp layer 220 is divided into a first region E1 where no magnetic beads MNB are disposed and a second region E2 where magnetic beads MNB are disposed. The first region E1 includes a plurality of subregions SE. The plurality of subregions SE are arranged in rows and columns on one surface of the stamp layer 220.

[0087] The first region E1 may be smaller than the area of ​​the region LEZ where the light-emitting element LE is disposed. The second region E2 may be the region excluding the first region E1. The region LEZ where the light-emitting element LE is disposed has the same size and shape as one surface of the light-emitting element LE. Therefore, the area of ​​the sub-region SE may be smaller than the area of ​​one surface of the light-emitting element LE.

[0088] A plurality of magnetic beads MNB are arranged in a single layer in the second region E2. In addition, the magnetic beads MNB surrounding the subregion SE in the second region E2 may overlap with the region LEZ where the light-emitting element LE is arranged.

[0089] A plurality of magnetic beads MNB can be arranged by patterning one surface of the stamp layer 220 using photoresist, by picking and placing using a separate stamp, or by applying one or more external forces such as static electricity or magnetic force.

[0090] The magnetic plate 30 may have an area that can cover the entire stamp layer 220 .

[0091] The magnetic plate 30 is detachably disposed on the top or bottom of the stamp member 20. For example, the magnetic plate 30 can be detachably disposed on the top of the base layer 210.

[0092] When the magnetic plate 30 is disposed on one side of the base layer 210, the magnetic beads MNB disposed on one side of the stamp layer 220 can be immobilized by the attractive force between the magnetic plate 30 and the magnetic beads MNB.

[0093] The magnetic plate 30 can be a permanent magnet or an electromagnet.

[0094] 7, with the magnetic beads MNB disposed on one surface of the stamp layer 220, the magnetic plate 30 can be disposed on the lower surface of the stamp layer 220. For example, the magnetic plate 30 can be disposed so as to face the magnetic beads MNB.

[0095] When the magnetic plate 30 is placed on the lower surface of the stamp member 20, an attractive force is generated between the magnetic beads MNB and the magnetic plate 30. The attractive force between the magnetic beads MNB and the magnetic plate 30 pulls the magnetic beads MNB in ​​the downward direction of the magnetic plate 30. As a result, the magnetic beads MNB can be detached from the lower surface of the stamp member 20 (e.g., one surface of the stamp layer 220) and placed on the upper surface of the magnetic plate 30.

[0096] FIG. 8 is a diagram showing a light emitting element transfer device according to an embodiment.

[0097] The light-emitting element transfer device may include a stamp assembly SA, a stage ST, and a magnetic plate MP. The stamp assembly SA may be the stamp assembly SA described with reference to FIGS. 5 to 7. In the embodiment described with reference to FIG. 8, the magnetic plate 30 of the stamp assembly SA is referred to as the first magnetic plate 30, and the magnetic plate MP is referred to as the second magnetic plate MP to distinguish it from the magnetic plate 30 of the stamp assembly SA. The second magnetic plate MP may be a permanent magnet or an electromagnet.

[0098] The stage ST supports a substrate. The substrate may be a display substrate, which is a donor substrate DS or a target substrate. The donor substrate DS may include, but is not limited to, an adhesive layer on its upper surface. The donor substrate DS is disposed on the stage ST. A light-emitting element LE is disposed on the donor substrate DS.

[0099] The second magnetic plate MP may have an area that covers the entire stamp layer 220 .

[0100] The second magnetic plate MP may be detachably disposed below the stage ST, or, if the second magnetic plate MP is an electromagnet, may be fixedly disposed below the stage ST.

[0101] The stamp member 20 is disposed above the stage ST, and the first magnetic plate 30 is disposed above the stamp member 20.

[0102] The position of the magnetic beads MNB can be changed according to the magnetic forces of the first magnetic plate 30 and the second magnetic plate MP.

[0103] For example, if the first magnetic plate 30 and the second magnetic plate MP are each permanent magnets, and the first magnetic plate 30 is in contact with one side of the stamp member 20 and the second magnetic plate MP is positioned in a location where it is not affected by the magnetic force from the stage ST, the magnetic beads MNB can be placed on one side of the stamp member 20. Note that if the first magnetic plate 30 is positioned in a location where it is not affected by the magnetic force from the stamp member 20, and the second magnetic plate MP is positioned on one side of the stage, and the stamp member 20 is positioned in a location where it is in contact with one side of the light-emitting element LE, the stamp member 20 is positioned within a range where it is not affected by the magnetic force of the second magnetic plate MP. Therefore, the magnetic beads MNB placed on one side of the stamp member 20 can be detached from one side of the stamp member 20 and transferred to the donor substrate DS.

[0104] FIG. 9 is a flowchart illustrating a method for transferring a light-emitting element according to an embodiment.

[0105] Figures 10 to 19 are cross-sectional views illustrating a method for transferring a light-emitting device according to another embodiment. Figures 10 to 19 are cross-sectional views illustrating a method for transferring a light-emitting device using the light-emitting device transferring apparatus described with reference to Figure 8. The stamp assembly SA described with reference to Figures 10 to 19 corresponds to the stamp assembly SA described with reference to Figures 5 to 7.

[0106] The transfer method of the light emitting element shown in FIG. 9 as well as FIG. 10 to FIG. 19 will be described below.

[0107] First, magnetic beads MNB are arranged on one surface of the stamp member 20 (S110 in FIG. 9).

[0108] Referring to FIG. 10, a plurality of magnetic beads MNB can be arranged by patterning one surface of the stamp layer 220 using photoresist, by picking and placing using a separate stamp, or by applying one or more external forces such as static electricity or magnetic force.

[0109] As described with reference to FIG. 6, a plurality of magnetic beads MNB are arranged in the second region E2 of the stamp layer 220.

[0110] Next, the first substrate DS and the stamp member 20 are placed on the stage ST (S120 in FIG. 9).

[0111] 11, an adhesive layer is applied on the first substrate DS, and a plurality of light emitting elements LE are arranged on the adhesive layer of the first substrate DS.

[0112] The first substrate DS may be disposed on the stage ST such that the plurality of light emitting elements LE are located thereon.

[0113] The stamp member 20 may be disposed on the upper portion of the first substrate DS, and a plurality of magnetic beads MNB arranged on one surface of the stamp member 20 may be disposed so as to face a plurality of light-emitting elements LE.

[0114] The stamp member 20 may be positioned such that the subregions SE of the stamp layer 220 overlap the light emitting elements LE.

[0115] The sub-regions SE are arranged to overlap the light-emitting elements LE.

[0116] Next, the light emitting element LE arranged on the first substrate DS is separated from the first substrate DS and lifted up using the stamp member 20 (S130 in FIG. 9).

[0117] Referring to FIG. 12, the stamp member 20 is brought into contact with one surface of the light-emitting element LE, and the stamp member 20 presses the light-emitting element LE downward from above.

[0118] The sub-region SE of the stamp member 20 overlaps with the light-emitting element LE, but because the area of ​​the sub-region SE is smaller than the area of ​​one surface of the light-emitting element LE, some of the magnetic beads MNB1, MNB2 surrounding the sub-region SE are arranged on the upper surface of the light-emitting element LE. In other words, some of the magnetic beads MNB1, MNB2 surrounding the sub-region SE overlap with the outside of the light-emitting element LE. By applying pressure, the magnetic beads MNB1, MNB2 overlapping with the outside of the light-emitting element LE are embedded inside the stamp layer 220, and the light-emitting element LE adheres to the stamp layer 220 in the sub-region SE.

[0119] Then, referring to FIG. 13, the stamp member 20 lifts up the light-emitting element LE.

[0120] The adhesive strength of the stamp layer 220 is greater than that of the first substrate DS, so that when the stamp member 20 is lifted, the light emitting element LE is separated from the first substrate DS and lifted along with the stamp member 20.

[0121] Next, the light emitting element LE is transferred onto the second substrate SS using the stamp member 20 (S140 in FIG. 9).

[0122] Referring to FIG. 14, the stamp member 20 is aligned above the second substrate SS.

[0123] The second substrate SS may be, but is not limited to, a relay substrate different from the first substrate as a target substrate onto which the light-emitting elements are transferred. For example, the second substrate SS may be a backplane substrate for manufacturing the display panel 100 described in FIG.

[0124] If the second substrate SS is another intermediate substrate, an adhesive layer may be disposed on the upper surface thereof. The adhesive strength of the adhesive layer of the second substrate SS may be greater than the adhesive strength of the stamp layer 220.

[0125] Referring to FIG. 15, after the light emitting element LE is brought into contact with the upper part of the second substrate SS, the stamp member 20 presses the light emitting element LE downward from above.

[0126] When an adhesive layer is disposed on the second substrate SS, the light emitting element LE adheres to the adhesive layer of the second substrate SS.

[0127] 16, when the second magnetic plate MP is placed on the underside of the stage ST, an attractive force is generated between the magnetic bead MNB of the stamp member 20 and the second magnetic plate MP. Therefore, the attractive force between the magnetic bead MNB and the second magnetic plate MP pulls the magnetic bead MNB downward toward where the second magnetic plate MP is placed. At this time, the magnetic beads MNB1 and MNB2 placed above the light-emitting element LE are also pulled downward. Therefore, the magnetic beads MNB1 and MNB2 pressurize the light-emitting element LE downward. The pressure of the magnetic beads MNB1 and MNB2 due to the attractive force with the second magnetic plate MP is useful when peeling the light-emitting element LE from the stamp member 20.

[0128] When the second magnetic plate MP is a permanent magnet, a magnetic force can be exerted on the magnetic beads by attaching or detaching the second magnetic plate MP to or from the stage ST, as shown in Fig. 16. For example, the second magnetic plate MP can be attached to the stage ST to exert a magnetic force on the magnetic beads, and can be detached from the stage ST to no longer exert a magnetic force on the magnetic beads.

[0129] If the second magnetic plate MP is an electromagnet, the second magnetic plate MP can exert a magnetic force on the magnetic beads by controlling the current while the second magnetic plate MP is attached to the stage ST. For example, the second magnetic plate MP can exert a magnetic force on the magnetic beads by applying a current while the second magnetic plate MP is attached to the stage ST, and can not exert a magnetic force on the magnetic beads by not applying a current.

[0130] For example, referring to FIG. 17, the stamp member 20 is lifted to separate the light emitting element LE from the stamp member 20 .

[0131] At this time, the magnetic beads MNB1 and MNB2 arranged above the light-emitting element LE press the light-emitting element LE downward, thereby helping to prevent the light-emitting element LE from lifting up along the stamp member 20.

[0132] Next, the plurality of magnetic beads MNB are collected from the second substrate SS onto the stamp member 20 (S150 in FIG. 9).

[0133] 18 and 19, the second magnetic plate MP is moved to a position where it does not exert a magnetic force on the plurality of magnetic beads MNB, and the first magnetic plate 230 is placed on top of the stamp member 20 (above the base layer 210). When the first magnetic plate 230 is placed on top of the stamp member 20, an attractive force is generated between the plurality of magnetic beads MNB and the first magnetic plate 230, attracting the plurality of magnetic beads MNB toward the first magnetic plate 230. This allows the plurality of magnetic beads MNB to be recovered from the second substrate SS to the stamp member 20.

[0134] According to one embodiment, the problem of light emitting elements remaining on one side of the donor substrate or stamp due to incomplete transfer can be minimized by using magnetic beads to pick up the light emitting elements, thereby improving the product quality and yield of the display device during the transfer process.

[0135] Furthermore, repair and stamp cleaning steps are no longer necessary, which reduces equipment costs and process costs.

[0136] Although the present invention has been described above with reference to the accompanying drawings, it should be understood that the present invention is not limited to the above-described embodiments and can be manufactured in various different forms, and that those skilled in the art will understand that the present invention can be embodied in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not limiting. [Explanation of symbols]

[0137] LE light-emitting element SA Stamp Assembly 20 Stamping material 210 base layer 220 Stamp Layer 30 Magnetic Plate MNB magnetic beads

Claims

1. a stamp member including a stamp layer and a base layer; a magnetic plate having a magnetic force on the upper surface of the base layer; a plurality of magnetic beads that are attachable to and detachable from the stamp layer by the magnetic force of the magnetic plate.

2. The stamp assembly according to claim 1 , wherein the magnetic beads are ferromagnetic particles having a size of 10 nm or less.

3. The stamp layer is divided into a first region where the magnetic beads are not disposed and a second region where the magnetic beads are disposed, The stamp assembly of claim 1 , wherein the first region comprises a plurality of sub-regions.

4. The stamp assembly according to claim 3 , wherein the sub-regions correspond to positions where light-emitting elements are attached, and the area of ​​the sub-regions is smaller than the area of ​​one surface of the light-emitting elements.

5. The stamp assembly of claim 1 , wherein the stamp layer has elasticity and adhesiveness on one surface.

6. The stamp assembly of claim 1 , wherein the magnetic plate is an electromagnet or a permanent magnet.

7. a stage for supporting the substrate; a stamp member including a stamp layer and a base layer; a first magnetic plate having a magnetic force on the upper surface of the base layer; a plurality of magnetic beads that can be attached to and detached from the stamp layer by the magnetic force of the first magnetic plate; a second magnetic plate disposed below the stage and having a magnetic force.

8. The stamp layer is divided into a first region where the magnetic beads are not disposed and a second region where the magnetic beads are disposed, The light-emitting element transfer device according to claim 7 , wherein the first region includes a plurality of sub-regions.

9. The light-emitting element transfer device according to claim 8 , wherein the sub-regions correspond to positions where the light-emitting elements are attached, and the area of ​​the sub-regions is smaller than the area of ​​one surface of the light-emitting elements.

10. 9. The light emitting device transfer apparatus according to claim 8, wherein the substrate comprises at least one of a donor substrate on which light emitting elements are arranged and a target substrate that receives the light emitting elements transferred from the donor substrate.

11. 8. The light-emitting element transfer device according to claim 7, wherein the stamp layer has elasticity and adhesiveness on one surface.

12. The light-emitting element transfer device of claim 7 , wherein the first magnetic plate and the second magnetic plate are either electromagnets or permanent magnets.

13. arranging a plurality of magnetic beads on one surface of a stamp member; placing the stamp member on the donor substrate such that the magnetic beads face light-emitting elements on the donor substrate; Lifting the light emitting device with the stamp member; placing the stamp member on the target substrate such that the light emitting element faces the target substrate; disposing a first magnetic plate under the target substrate and transferring the light emitting element and a plurality of magnetic beads to the target substrate; and placing a second magnetic plate on the upper surface of the stamp member to collect the plurality of magnetic beads.

14. In the step of lifting the light emitting element with the stamp member, The method of claim 13 , wherein the stamp member includes a stamp layer having adhesive strength on one surface, and the light emitting device is lifted up by applying pressure to the stamp layer so that the light emitting device adheres to the stamp layer.

15. The stamp layer is divided into a first region where the magnetic beads are not disposed and a second region where the magnetic beads are disposed, the first region includes a plurality of sub-regions; The method of claim 14 , wherein the sub-regions correspond to positions where the light-emitting elements are to be attached, and the area of ​​the sub-regions is smaller than the area of ​​one surface of the light-emitting elements.

16. 16. The method for transferring a light-emitting element according to claim 15, wherein when the stamp member contacts the light-emitting element, the magnetic beads are arranged in the second region, and some of the magnetic beads surrounding the sub-region are arranged on the upper surface of the light-emitting element, and are embedded inside the stamp layer of the stamp member by pressing the stamp member, so that one surface of the light-emitting element adheres to the stamp layer.

17. The step of disposing a first magnetic plate under the target substrate and transferring the light emitting device and the plurality of magnetic beads to the target substrate includes: The method for transferring a light-emitting element according to claim 13, further comprising: placing a first magnetic plate below the target substrate; pulling the magnetic beads arranged on one surface of the stamp member downward by the magnetic force of the first magnetic plate; and pressing the light-emitting element downward against the magnetic beads overlapping the upper part of the light-emitting element.

18. 18. The method of transferring a light-emitting element according to claim 17, wherein the first magnetic plate is a permanent magnet and is disposed adjacent to a lower portion of the target substrate to exert a magnetic force on the magnetic beads.

19. The method of claim 17 , wherein the first magnetic plate is an electromagnet, fixed to a lower portion of a stage on which the target substrate is placed, and applies a magnetic force to the magnetic beads by applying a current thereto.

20. In the step of placing a second magnetic plate on the upper surface of the stamp member and collecting the magnetic beads, The method for transferring a light-emitting element described in claim 13, wherein by placing the second magnetic plate on the upper surface of the stamp member, an attractive force is generated between the second magnetic plate and the plurality of magnetic beads, causing the plurality of magnetic beads to move from the top of the target substrate and the light-emitting element to one side of the stamp member.

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