Donor substrate and LED transfer method using the same

Abstract

A donor substrate according to an exemplary embodiment of the present disclosure includes: a substrate; a resin layer disposed on one surface of the substrate; a plurality of first protrusions on the resin layer; and an alignment mark disposed on the surface of the substrate. Therefore, since the alignment mark is disposed on the surface of the substrate, positional variations in the alignment mark caused by the resin layer can be reduced.

Description

Technical Field

[0001] The present disclosure relates to a display device, and more particularly, to a donor substrate having improved alignment accuracy and an LED transfer method using the donor substrate. Background Art

[0002] Display devices used in computer monitors, televisions, and mobile phones include organic light emitting displays (OLEDs) that emit light by themselves and liquid crystal displays (LCDs) that require a separate light source.

[0003] Such display devices are being applied to an increasing number of fields including not only computer monitors and televisions but also personal mobile devices, and thus, display devices having reduced size and weight while having a wide display area are being researched.

[0004] In recent years, display devices including light-emitting diodes (LEDs) have attracted attention as next-generation display devices. Because LEDs are made of inorganic materials rather than organic materials, they have excellent reliability and a longer lifespan than liquid crystal displays or organic light-emitting displays. In addition, LEDs have high luminous speed, high luminous efficiency, and excellent stability due to high impact resistance, and can display high-brightness images. Summary of the Invention

[0005] Technical issues

[0006] In order to manufacture a display device including LEDs, a process of transferring LEDs manufactured on a wafer to a donor substrate and then transferring the LEDs transferred to the donor substrate to a substrate of a display device is used.

[0007] Specifically, in the primary transfer process of transferring the plurality of LEDs from the wafer to the donor substrate, after the wafer and the donor substrate are aligned and bonded, the plurality of LEDs can be transferred to the donor substrate. In the secondary transfer process of transferring the plurality of LEDs from the donor substrate to the display panel, after the display panel and the donor substrate are aligned and bonded, the plurality of LEDs are transferred to the display panel, thereby completing the formation of the display device.

[0008] At this time, in order to align the donor substrate and the wafer, and the donor substrate and the display panel, alignment protrusions are formed on the donor substrate using the same material and the same process as used to temporarily attach the plurality of LEDs to the plurality of protrusions. Based on the alignment protrusions, the donor substrate and the wafer can be aligned, and the donor substrate and the display panel can be aligned. However, the inventors of the present disclosure have recognized that since the donor substrate is continuously used in the primary transfer process and the secondary transfer process, the alignment key may be damaged or its position may be deformed due to external impact and friction during the processing process.

[0009] In addition, the multiple protrusions and alignment protrusions used in the donor substrate can be formed of a polymer having high transmittance and viscoelasticity, such as polydimethylsiloxane (PDMS). For example, when the alignment protrusion is formed of PDMS, since the alignment protrusion is formed by coating and curing PDMS, the edge of the alignment protrusion is not clearly formed and may be rounded and not clearly formed. Therefore, the inventors of the present disclosure have recognized such a defect, that is, due to the characteristics of the alignment protrusion, the edge of the alignment protrusion is somewhat unclear, and it is difficult to identify the alignment protrusion because the alignment protrusion is confused with the surrounding stains. In addition, when the identification of the alignment protrusion is delayed in the processing equipment, the processing time is thereby increased, and the subsequent process is also delayed, resulting in an uneven distribution of the entire processing time.

[0010] Thus, the inventors of the present disclosure have invented a donor substrate having alignment marks with sharp contrast and minimal damage and positional deformation.

[0011] An object to be achieved by the present disclosure is to provide a donor substrate in which an alignment mark can be easily recognized by improving the contrast between the alignment mark of the donor substrate and the remaining components of the donor substrate.

[0012] Another object to be achieved by the present disclosure is to provide a donor substrate including an alignment mark, in which damage due to repeated use and external impact of the donor substrate is reduced.

[0013] Another object to be solved by the present disclosure is to provide a donor substrate including an alignment mark so that positional deformation due to stretching of a resin layer of the donor substrate is reduced.

[0014] Another object to be addressed by the present disclosure is to provide a donor substrate capable of reducing processing time during LED transfer by easily recognizing alignment marks.

[0015] The objects of the present disclosure are not limited to the above objects, and other objects not mentioned above can be clearly understood by those skilled in the art through the following description.

[0016] Technical Solution

[0017] According to an exemplary embodiment of the present disclosure, a donor substrate includes: a substrate; a resin layer disposed on one surface of the substrate; a plurality of first protrusions on the resin layer; and an alignment mark disposed on the surface of the substrate. Therefore, by providing the alignment mark on the surface of the substrate, positional variations of the alignment mark caused by the resin layer can be reduced.

[0018] According to another exemplary embodiment of the present disclosure, a donor substrate and an LED transfer method using the donor substrate include: aligning a wafer and a donor substrate; and transferring a plurality of LEDs on the wafer to the donor substrate. The donor substrate includes a substrate having alignment marks marked thereon; a resin layer on the substrate; and a plurality of first protrusions protruding from the resin layer. The wafer and the donor substrate are aligned by aligning the alignment marks on the donor substrate with alignment keys on the wafer. Therefore, since the donor substrate formed from a substrate displaying the alignment marks is used, the alignment marks can be easily identified during LED transfer, and process delays can be reduced.

[0019] Additional matters regarding exemplary embodiments are included in the detailed description and accompanying drawings.

[0020] Beneficial effects

[0021] According to the present disclosure, the contrast between the alignment mark and the substrate and the resin layer in the donor substrate is increased, so that the alignment mark can be easily recognized.

[0022] According to the present disclosure, the alignment mark is directly formed on the substrate of the donor substrate, thereby reducing movement of the alignment mark due to stretching of the resin layer.

[0023] According to the present disclosure, damage to the alignment mark due to repeated use of the donor substrate or external impact can be reduced.

[0024] According to the present disclosure, the alignment mark of the donor substrate is easily recognized, and thus process delays due to non-recognition of the alignment mark can be reduced.

[0025] Effects according to the present disclosure are not limited to the contents of the above examples, and more various effects are included in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a plan view of a donor substrate according to an exemplary embodiment of the present disclosure.

[0027] Figure 2a It is along Figure 1 Cross-sectional view taken along IIa-IIa'.

[0028] Figure 2b It is along Figure 1 Cross-sectional view taken along IIb-IIb'.

[0029] Figure 3 and Figure 4 is a process flow chart for explaining a donor substrate and an LED transfer method using the donor substrate according to an exemplary embodiment of the present disclosure.

[0030] Figure 5 and Figure 6 2 is a schematic process view for explaining an LED transfer method according to an exemplary embodiment of the present disclosure.

[0031] Figures 7a to 7c is an enlarged plan view of a donor substrate according to a comparative example.

[0032] Figure 8 is an enlarged rear view of a donor substrate according to another exemplary embodiment of the present disclosure.

[0033] Figure 9 is a cross-sectional view of a donor substrate according to yet another exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] The advantages and features of the present disclosure and the methods for achieving these advantages and features will become clear by referring to the exemplary embodiments and drawings described in detail below. However, the present disclosure is not limited to the exemplary embodiments disclosed herein, but will be implemented in various forms. The illustrative embodiments are provided by way of example only so that those of ordinary skill in the art can fully understand what is disclosed and the scope of the present disclosure. Therefore, the present disclosure will be limited only by the scope of the appended claims.

[0035] The shapes, sizes, ratios, angles, quantities, etc. illustrated in the accompanying drawings for describing the exemplary embodiments of the present disclosure are merely examples, and the present disclosure is not limited thereto. The same figure numerals generally represent the same elements throughout the specification. Further, in the following description of the present disclosure, in order to avoid unnecessarily obscuring the subject matter of the present disclosure, detailed descriptions of known related technologies may be omitted. Terms such as "including," "having," and "consisting of..." used herein generally mean that other components are allowed to be added, unless the word "only" is used when using the term. Unless expressly provided otherwise, any singular reference may include the plural.

[0036] Even if not explicitly stated, components are interpreted as including ordinary margins of error.

[0037] When terms such as "on," "over," "below," and "near" are used to describe the positional relationship between two components, one or more components may be positioned between the two components, unless the words "immediately next to" or "directly" are used when these terms are used.

[0038] When an element or layer is referred to as being “on” another element or layer, the other layer or element can be directly on the other element or interposed therebetween.

[0039] Although the terms "first," "second," etc. are used to describe various components, these components are not restricted by these terms. These terms are only used to distinguish one component from other components. Therefore, the first component mentioned below may be the second component in the technical concept of the present disclosure.

[0040] Like reference numerals generally refer to like elements throughout the specification.

[0041] The size and thickness of each component shown in the drawings are illustrated for convenience of description, and the present disclosure is not limited to the illustrated sizes and thicknesses of the components.

[0042] The features of the various embodiments of the present disclosure may be partially or completely adhered to or combined with each other, and may be interlocked and operated in various technical ways, and these embodiments may be performed independently of or in association with each other.

[0043] Hereinafter, a donor substrate and an LED transfer method using the same according to exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0044] Figure 1 is a plan view of a donor substrate according to an exemplary embodiment of the present disclosure. Figure 2a It is along Figure 1 Cross-sectional view taken along IIa-IIa'. Figure 2b It is along Figure 1 The cross-sectional view taken along IIb-IIb' in FIG. Figures 1 to 2b , the donor substrate 100 according to the exemplary embodiment of the present disclosure includes a substrate 110 , an adhesive layer 120 , a resin layer 130 , a plurality of first protrusions 131 , a plurality of second protrusions 132 , and an alignment mark 160 .

[0045] The substrate 110 is configured to support various components included in the donor substrate 100 and may be formed of a material that is more rigid than the resin layer 130 so as to reduce warping of the resin layer 130. For example, the substrate 110 may be formed to include a polymer or plastic and may be formed of PC (polycarbonate) or PET (polyethylene terephthalate), but is not limited thereto.

[0046] The substrate 110 includes a transferred region 110A and a non-transferred region 110B.

[0047] The transfer region 110A is a region overlapping the resin layer 130. The transfer region 110A is disposed to overlap the resin layer 130, the plurality of first protrusions 131, and the plurality of second protrusions 132, and the transfer region 110A can support the resin layer 130, the plurality of first protrusions 131, and the plurality of second protrusions 132. The transfer region 110A is a region to which the plurality of LEDs are temporarily transferred, and can be disposed to overlap at least a portion of a wafer or a display panel during the transfer process.

[0048] Meanwhile, the wafer is a substrate on which a plurality of LEDs are formed. The plurality of LEDs formed on the wafer are first transferred to the donor substrate 100, and the plurality of LEDs on the donor substrate 100 are secondarily transferred to the substrate 110, thereby forming a display panel. This will be referred to later. Figures 3 to 6 Provide a detailed description.

[0049] The non-transferred region 110B is a region protruding outside the resin layer 130. The non-transferred region 110B is a region that does not overlap with the resin layer 130. The non-transferred region 110B is a region where the plurality of LEDs are not disposed. The identification pattern 140 and the directional pattern 150 may be disposed in the non-transferred region 110B instead of the plurality of LEDs.

[0050] The identification pattern 140 is a pattern formed in the non-transfer area 110B to identify the donor substrate 100. A plurality of donor substrates 100 can be managed by using a unique identification pattern 140 provided to each donor substrate 100. The identification pattern 140 can be provided on the upper surface or the rear surface of the substrate 110 and can be formed by a printing method or a laser engraving method. For example, the identification pattern 140 can be an ID or a barcode composed of numbers or characters, but is not limited thereto. Meanwhile, although in Figure 1 The middle recognition pattern 140 is shown as being formed on the upper right side of the donor substrate 100 , the recognition pattern 140 may also be variously provided in the non-transfer region 110B, and the number and arrangement of the recognition patterns 140 are not limited thereto.

[0051] The directional pattern 150 is a pattern formed in the non-transfer region 110B to distinguish the direction of the donor substrate 100. For example, when the donor substrate 100 is placed in a processing device, if the donor substrate 100 is placed in the opposite direction, the LED may be transferred to a position different from the designed position, or a defect may occur. Therefore, the directional pattern 150 can be set in any one of the non-transfer regions 110B to distinguish the direction of the donor substrate 100. The directional pattern 150 can be formed by a printing method, a laser engraving method, etc. For example, in addition to Figure 1In addition to the linear pattern shown in , the direction pattern 150 can also be formed by characters or graphics. In addition, in addition to the printing method or the laser engraving method, the direction pattern 150 can also be formed by chamfering the edge of the substrate 110, but is not limited thereto.

[0052] The resin layer 130 is provided on one surface of the substrate 110. The resin layer 130 provided on the transfer region 110A of the substrate 110 can support the plurality of first protrusions 131 to which the plurality of LEDs are attached during the transfer process. The resin layer 130 can be formed of a polymer resin having viscoelasticity, for example, the resin layer 130 can be composed of polydimethylsiloxane (PDMS), polyurethane acrylate (PUA), polyethylene glycol (PEG), polymethyl methacrylate (PMMA), polystyrene (PS), epoxy resin, polyurethane resin, acrylic resin, etc., but is not limited thereto.

[0053] The resin layer 130 includes an active region 130A and a barrier region 130B.

[0054] The active area 130A is an area provided with a plurality of first protrusions 131. The active area 130A is an area in which the plurality of first protrusions 131 to which a plurality of LEDs are attached are provided, and may be provided to overlap at least a portion of a wafer or a display panel during a transfer process.

[0055] The barrier region 130B is a region provided with the plurality of second protrusions 132. The barrier region 130B is a region provided with the plurality of second protrusions 132 for reducing deformation of the donor substrate 100, and may be provided to surround the active region 130A.

[0056] A plurality of first protrusions 131 are provided in the active area 130A of the resin layer 130. The plurality of first protrusions 131 are protrusions on which the plurality of LEDs are provided, and may be formed so as to extend from one surface of the resin layer 130. The plurality of first protrusions 131 may be formed integrally with the resin layer 130, and may be formed of a polymer material having viscoelasticity in the same manner as the resin layer 130. For example, the plurality of first protrusions 131 may be formed of polydimethylsiloxane (PDMS), polyurethane acrylate (PUA), polyethylene glycol (PEG), polymethyl methacrylate (PMMA), polystyrene (PS), epoxy resin, polyurethane resin, acrylic resin, etc., but is not limited thereto.

[0057] The LEDs may be temporarily attached to the upper surfaces of the plurality of first protrusions 131. Specifically, the plurality of LEDs formed on the wafer may be transferred to the upper surfaces of the plurality of first protrusions 131, and the plurality of LEDs may remain temporarily attached to the upper surfaces of the plurality of first protrusions 131 until being transferred to the display panel.

[0058] In this case, the plurality of first protrusions 131 can be arranged to correspond to the plurality of sub-pixels of the display panel, respectively. For example, when a plurality of LEDs are transferred to the display panel, the plurality of LEDs are transferred to correspond to the plurality of corresponding sub-pixels of the display panel. If the plurality of LEDs transferred to the donor substrate 100 are transferred simultaneously, the plurality of LEDs transferred to the display panel can be arranged to correspond to the plurality of corresponding sub-pixels only if the plurality of LEDs on the donor substrate 100 are arranged to correspond to the plurality of corresponding sub-pixels. However, the arrangement and spacing of the plurality of first protrusions 131 can be varied according to the design, but are not limited thereto.

[0059] A plurality of second protrusions 132 are provided in the barrier region 130B of the resin layer 130. The plurality of second protrusions 132 are protrusions that are not provided with a plurality of LEDs and are provided to reduce deformation of the donor substrate 100, and the plurality of second protrusions 132 may be formed to extend from one surface of the resin layer 130. The plurality of second protrusions 132 may be formed integrally with the resin layer 130 and may be formed of a polymer material having viscoelasticity in the same manner as the resin layer 130. For example, the plurality of second protrusions 132 may be formed of polydimethylsiloxane (PDMS), polyurethane acrylate (PUA), polyethylene glycol (PEG), polymethyl methacrylate (PMMA), polystyrene (PS), epoxy resin, polyurethane resin, acrylic resin, etc., but is not limited thereto.

[0060] The plurality of second protrusions 132 are protrusions that are used to reduce deformation of the resin layer 130 and the plurality of first protrusions 131 due to impact applied to the donor substrate 100 during the transfer process. For example, after bonding the wafer and donor substrate 100, when transferring the plurality of LEDs onto the donor substrate 100, an impact may be applied to the donor substrate 100 while the plurality of LEDs are moving on the donor substrate 100. When this impact is applied to the donor substrate 100, the position or shape of the resin layer 130 and the plurality of first protrusions 131 may be deformed. In this case, the plurality of second protrusions 132, arranged around the active area 130A, maintain their bonded state to the wafer and reduce deformation of the resin layer 130 and the plurality of first protrusions 131.

[0061] exist Figures 1 to 2b, the plurality of first protrusions 131 and the plurality of second protrusions 132 are shown to have the same height, but the heights of the plurality of first protrusions 131 and the plurality of second protrusions 132 may be different from each other. For example, the height of the plurality of first protrusions 131 may be higher than the height of the plurality of second protrusions 132, and the height of the plurality of first protrusions 131 may be lower than the height of the plurality of second protrusions 132, but they are not limited thereto.

[0062] At the same time, Figures 1 to 2b , although the plurality of first protrusions 131 and the plurality of second protrusions 132 are shown as being provided on the resin layer 130, the resin layer 130 may be omitted, and only the plurality of first protrusions 131 and the plurality of second protrusions 132 may be provided on the substrate 110 according to design, but they are not limited thereto. In addition, only the plurality of first protrusions 131 may be provided, and the plurality of second protrusions 132 may be omitted according to design, but they are not limited thereto.

[0063] In addition, although it has been described herein that the resin layer 130 and the plurality of first and second protrusions 131 and 132 are integrally formed, the resin layer 130 and the plurality of first and second protrusions 131 and 132 may be separately formed, but they are not limited thereto.

[0064] exist Figures 1 to 2b , the plurality of first protrusions 131 and the plurality of second protrusions 132 are shown as being formed by columns having a quadrilateral cross-section, but the plurality of first protrusions 131 and the plurality of second protrusions 132 may be formed by columns having various shapes, such as circular, elliptical, and polygonal cross-sections, but they are not limited thereto.

[0065] The adhesive layer 120 is provided between the resin layer 130 and the substrate 110. The adhesive layer 120 bonds the resin layer 130 and the substrate 110 to each other. The adhesive layer 120 may be formed of a material having an adhesive property, and may be formed of, for example, an optically clear adhesive (OCA), a pressure sensitive adhesive (PSA), etc., but is not limited thereto.

[0066] However, depending on the design, the adhesive layer 120 may be omitted. For example, the resin layer 130 may be formed by directly coating the material constituting the resin layer 130 on the substrate 110 and then curing the material. In this case, since the resin layer 130 can be attached to the substrate 110 even without the adhesive layer 120, the adhesive layer 120 may be omitted depending on the design, but is not limited thereto.

[0067] Alignment mark 160 is formed on the surface opposite to the one surface of substrate 110. Alignment mark 160 is a component used to align and parallelize donor substrate 100 with a wafer or display panel. Alignment mark 160 can be formed by printing a colored material on the surface of substrate 110 or by laser engraving (i.e., by burning the surface of substrate 110). Alternatively, alignment mark 160 can be formed by arranging a material having excellent reflectivity (e.g., chromium (Cr), silver (Ag), a silver alloy (Ag alloy), aluminum (Al), an aluminum alloy (Al alloy), molybdenum (Mo), or titanium (Ti)) on the surface opposite to the one surface of substrate 110, but is not limited thereto.

[0068] At the same time, the alignment mark 160 is Figure 1 Although shown as having a circular shape in FIG, the alignment mark 160 may be formed to have various shapes such as a cross, a ring, and a quadrangle in addition to the circle, considering the shape of the alignment key of the wafer, but is not limited thereto.

[0069] Meanwhile, the substrate 110, adhesive layer 120, and resin layer 130 can be formed from a material having a transmittance at least higher than that of the alignment mark 160 of the donor substrate 100. When the substrate 110, adhesive layer 120, and resin layer 130 are formed from a material having a transmittance higher than that of the alignment mark 160, the alignment mark 160 can be easily identified. If the transmittance of the alignment mark 160 is similar to that of the substrate 110, adhesive layer 120, and resin layer 130, it may be difficult to identify the alignment mark 160, and it may also be difficult to identify the alignment key of the wafer. Therefore, by forming the alignment mark 160 opaque, the contrast between the alignment mark 160 and the remaining components of the donor substrate 100 can be increased, and the alignment mark 160 can be easily identified.

[0070] In the following, reference will be made to Figures 3 to 6 A donor substrate 100 and an LED transfer method using the donor substrate 100 according to an exemplary embodiment of the present disclosure are described.

[0071] Figure 3 and Figure 4 is a process flow chart for explaining a donor substrate and an LED transfer method using the donor substrate according to an exemplary embodiment of the present disclosure. Figure 5 and Figure 6 : is a schematic process diagram for illustrating an LED transfer method according to an exemplary embodiment of the present disclosure. Specifically, Figure 3 is a flow chart illustrating a primary transfer process of transferring the plurality of LEDs 210 on the wafer 200 to the donor substrate 100 . Figure 4 is a flow chart illustrating a secondary transfer process of transferring the plurality of LEDs 210 on the donor substrate 100 to a display panel. Figure 5 2 is a schematic cross-sectional view for explaining a process of aligning the wafer 200 and the donor substrate 100 . Figure 6 The donor substrate 100 is Figure 1 A region X in FIG. 1 is a rear view showing a state in which the wafer 200 and the donor substrate 100 are aligned.

[0072] Reference Figure 3 In step S110 , the wafer 200 on which the plurality of LEDs 210 are formed is placed into a processing device.

[0073] Refer to it together Figure 5 Wafer 200 is a substrate on which multiple LEDs 210 are formed. Multiple LEDs 210 can be formed by growing a crystal layer of a material such as GaN or InGaN on wafer 200, cutting the crystal layer into individual chips, and forming electrodes thereon. Wafer 200 can be formed of, but is not limited to, sapphire, SiC, GaN, ZnO, or the like.

[0074] In this case, on one wafer 200 , a plurality of LEDs 210 emitting light of the same color may be formed, or a plurality of LEDs 210 emitting light of different colors may be formed.

[0075] The LED 210 is a semiconductor element that emits light when a voltage is applied thereto. As the LED 210, there are LEDs 210 that emit red light, green light, blue light, etc., and a combination of the LEDs 210 can realize emission of light of various colors including white.

[0076] The plurality of LEDs 210 can be formed in various structures, such as lateral, vertical, and flip-chip types. A lateral LED includes an n-electrode and a p-electrode disposed laterally on both sides of a light-emitting layer. A vertical LED includes an n-electrode and a p-electrode disposed above and below the light-emitting layer. A flip-chip LED has a structure substantially the same as that of a lateral LED. In a lateral LED, the n-electrode and the p-electrode are disposed laterally above the light-emitting layer, while in a flip-chip LED, the n-electrode and the p-electrode are disposed laterally below the light-emitting layer.

[0077] Next, in step S120 , the alignment key 220 on the wafer 200 placed in the processing equipment is inspected.

[0078] Refer to it together Figure 3 and Figure 5 , the alignment key 220 is set on the wafer 200.

[0079] The alignment keys 220 of the wafer 200 are marks for matching alignment and parallelism with the donor substrate 100 when the plurality of LEDs 210 of the wafer 200 are transferred to the donor substrate 100. For example, by aligning the alignment keys 220 of the wafer 200 with the alignment marks 160 of the donor substrate 100, the alignment and parallelism of the wafer 200 and the donor substrate 100 can be matched.

[0080] Return to reference Figure 3 , it is possible to check whether the alignment key 220 of the wafer 200 placed in the processing equipment is placed in the correct position. If the alignment key 220 of the wafer 200 is not checked, it is possible to return to the step of placing the wafer 200. If the alignment key 220 of the wafer 200 is not placed in the correct position, the alignment key 220 may be misaligned with the donor substrate 100 in the subsequent process. Therefore, after checking whether the alignment key 220 of the wafer 200 is present and in the correct position, the next process can be performed.

[0081] The donor substrate 100 is placed in the processing equipment in step S130 . When the donor substrate 100 is placed in the processing equipment, the donor substrate 100 may be input based on the direction pattern 150 of the donor substrate 100 .

[0082] Next, in step S140, the alignment marks 160 of the donor substrate 100 placed in the processing equipment are inspected. Specifically, as in step S120 of inspecting the alignment keys 220 of the wafer 200, it is possible to inspect whether the alignment marks 160 of the donor substrate 100 are correctly positioned. If the alignment marks 160 of the donor substrate 100 are not inspected, the process can return to the step of placing the donor substrate 100. If the donor substrate 100 is used as is without inspecting its alignment marks 160, it will be difficult to match the alignment and parallelism of the wafer 200 and the donor substrate 100, and defects may occur. Therefore, after inspecting the presence and correct position of the alignment marks 160 of the donor substrate 100, the next process can be performed.

[0083] At this time, the processing order of step S110 of placing the wafer 200 and step S120 of inspecting the alignment key 220 , step S130 of placing the donor substrate 100 and step S140 of inspecting the alignment mark 160 may be performed sequentially or simultaneously, and the processing order is not limited thereto.

[0084] Next, in step S150 , the wafer 200 , on which the alignment keys 220 have been inspected, and the donor substrate 100 , on which the alignment marks 160 have been inspected, are aligned.

[0085] Refer to it together Figure 3 and Figure 5In a state where the wafer 200 and the donor substrate 100 are arranged so that the plurality of LEDs 210 on the wafer 200 and the first protrusions 131 of the donor substrate 100 face each other, the alignment and parallelism of the wafer 200 and the donor substrate 100 can be matched. The wafer 200 and the donor substrate 100 can be aligned by aligning the center of the alignment key 220 of the wafer 200 with the center of the alignment mark 160 of the donor substrate 100. However, if it is unclear to identify the alignment key 220 of the wafer 200 or the alignment mark 160 of the donor substrate 100, the alignment key 220 and the alignment mark 160 can be rechecked by returning to steps S110 and S130 of placing the wafer 200 and / or the donor substrate 100 into the processing equipment.

[0086] In this case, the alignment marks 160 and the alignment keys 220 can be optically inspected and aligned by disposing the optical inspection device 300 outside the donor substrate 100 and the wafer 200. For example, the alignment marks 160 of the donor substrate 100 and the alignment keys 220 of the wafer 200 can be inspected by disposing the optical inspection device 300, such as a camera, outside the donor substrate 100. However, the alignment marks 160 of the donor substrate 100 and the alignment keys 220 of the wafer 200 can also be inspected by disposing the optical inspection device 300 outside the wafer 200 instead of outside the donor substrate 100.

[0087] As described above, the substrate 110, the adhesive layer 120, and the resin layer 130 of the donor substrate 100 may be formed of a material having a higher transmittance than the alignment mark 160 (i.e., a substantially transparent material). Therefore, even if the substrate 110, the adhesive layer 120, and the resin layer 130 of the donor substrate 100 are disposed between the optical inspection apparatus 300 and the alignment key 220 of the wafer 200, since the substrate 110, the adhesive layer 120, and the resin layer 130 are substantially transparent, the alignment key 220 of the wafer 200 may be inspected even in the optical inspection apparatus 300 outside the donor substrate 100.

[0088] In this case, the alignment key 220 of the wafer 200 may be formed of an opaque material, for example, a material having excellent reflectivity, to facilitate identification thereof. For example, the alignment key 220 may be formed of a material having excellent reflectivity, such as chromium (Cr), silver (Ag), a silver alloy (Ag alloy), aluminum (Al), an aluminum alloy (Al alloy), molybdenum (Mo), or titanium (Ti), or may be a structure plated with such a material, but is not limited thereto.

[0089] Meanwhile, the alignment mark 160 and the alignment key 220 may be inspected using a transmission method or a reflection method. The transmission method is a method of inspecting the alignment mark 160 on the surface opposite to one surface of the substrate 110 and the alignment key 220 of the wafer 200, and the alignment mark 160 and the alignment key 220 are visible through the transparent substrate 110, the adhesive layer 120, and the resin layer 130 in the optical inspection apparatus 300 outside the donor substrate 100, as shown in FIG. Figure 5 As shown in . The reflection method is a method in which a light source is further provided to irradiate light toward the alignment mark 160 and / or the alignment key 220, and the alignment mark 160 and / or the alignment key 220 is checked based on the light reflected from the alignment mark 160 and / or the alignment key 220. In this case, the transmission method or the reflection method can be used according to the size and material of the alignment mark 160 of the donor substrate 100 and the alignment key 220 of the wafer 200. Figure 5 In the drawings, for the convenience of description, the transmission method is shown, but is not limited thereto.

[0090] Reference Figure 5 and Figure 6 , when the opaque alignment mark 160 of the donor substrate 100 is formed to fill the edge of its interior, the alignment key 220 of the wafer 200 may have a size larger than the alignment mark 160 of the donor substrate 100. At least a portion of the alignment key 220 of the wafer 200 may be provided to protrude outside the alignment mark 160 of the donor substrate 100. For example, the alignment mark 160 of the donor substrate 100 may be formed in a black circular shape, and the alignment key 220 of the wafer 200 may have a diameter larger than that of the alignment mark 160 and may be formed in a ring shape with a hole formed in the center thereof, such as a ring, so that it can be provided to surround the alignment mark 160 of the donor substrate 100. However, the shapes of the alignment mark 160 and the alignment key 220 are not limited thereto.

[0091] If the alignment key 220 of the wafer 200 aligned with the alignment mark 160 of the donor substrate 100 has a size smaller than the alignment mark 160, the alignment key of the wafer 200 may be covered by the alignment mark 160 of the donor substrate 100. Therefore, it may be difficult to inspect the transmission image of the alignment key 220 of the wafer 200 covered by the alignment mark 160 in the optical inspection device 300 outside the donor substrate 100. Therefore, the alignment key 220 of the wafer 200 may have a size larger than the alignment mark 160 of the donor substrate 100 and may protrude outside the alignment mark 160.

[0092] Then, after the wafer 200 and the donor substrate 100 are aligned, the wafer 200 and the donor substrate 100 are bonded in step S160 , and the plurality of LEDs 210 on the wafer 200 are transferred to the donor substrate 100 in step S170 .

[0093] The wafer 200 and the donor substrate 100 may be combined such that the plurality of LEDs 210 of the wafer 200 and the plurality of first protrusions 131 of the donor substrate 100 face each other. Furthermore, at least a portion of the plurality of LEDs 210 of the wafer 200 may be transferred to the donor substrate 100. In this case, the transfer of the LEDs 210 from the wafer 200 to the donor substrate 100 may be performed in various ways. For example, a laser may be irradiated onto the LEDs 210 among the plurality of LEDs 210 to transfer them to the donor substrate 100, and the LEDs 210 irradiated with the laser may be separated from the wafer 200 and adhered to the plurality of first protrusions 131 of the donor substrate 100. The method of transferring the LEDs 210 from the wafer 200 to the donor substrate 100 may vary depending on the design, but is not limited thereto.

[0094] In the primary transfer process, after the donor substrate 100 and the wafer 200 are aligned and bonded using the alignment mark 160 and the alignment key 220 , the plurality of LEDs 210 of the wafer 200 may be transferred to the donor substrate 100 .

[0095] After the primary transfer process is completed, a secondary transfer process of transferring the plurality of LEDs 210 of the donor substrate 100 to a substrate of a display panel again may be performed, so that the display panel may be formed.

[0096] Reference Figure 4 In step S210 , the donor substrate 100 to which the plurality of LEDs 210 are attached is placed in a processing device, and the alignment mark 160 of the donor substrate 100 is inspected in step S220 .

[0097] Even in the secondary transfer process of transferring the plurality of LEDs 210 from the donor substrate 100 to the display panel, it is possible to recheck whether the alignment mark 160 of the donor substrate 100 placed in the processing equipment is in the correct position. In the primary transfer process of transferring the plurality of LEDs 210 from the wafer 200 to the donor substrate 100 or in the process of transporting the donor substrate 100, it is possible to check whether the alignment mark 160 is missing and whether the alignment mark 160 is placed in the correct position.

[0098] Next, in step S230, the display panel is placed in a processing device, and an alignment key of the display panel is checked in step S240.

[0099] In the display panel, display elements and circuits, lines, and components for driving the display elements are provided so that the display panel can display images. In this case, the display elements are multiple LEDs 210, and the multiple LEDs 210 can be provided in multiple sub-pixels and display images.

[0100] A driving circuit including a thin film transistor, a storage capacitor, a plurality of lines, a driver IC, etc. may be formed on the substrate of the display panel to drive each of the plurality of LEDs 210. In this case, the display panel used in the secondary transfer process may be a substrate on which at least a portion of the driving circuit is formed, but is not limited thereto.

[0101] It is possible to check whether the alignment key of the display panel placed in the processing equipment is placed in the correct position. The alignment key of the display panel is also a mark for matching the alignment and parallelism with the donor substrate 100. After checking whether the alignment key of the display panel is present and whether the alignment key is in the correct position, the next process can be performed.

[0102] Next, in step S250 , the donor substrate 100 , on which the alignment mark 160 has been inspected, and the display panel 100 , on which the alignment key has been inspected, are aligned.

[0103] When the donor substrate 100 and the display panel are positioned so that the display panel and the plurality of LEDs 210 on the donor substrate 100 face each other, the alignment and parallelism of the donor substrate 100 and the display panel can be matched. The donor substrate 100 and the display panel can be aligned by aligning the alignment marks 160 on the donor substrate 100 with the alignment keys on the display panel. However, if it is difficult to identify the alignment marks 160 on the donor substrate or to perform alignment, the process may return to the step of placing the donor substrate 100 back into the processing equipment.

[0104] At this time, as in the case of the donor substrate 100 and the wafer 200, the alignment mark 160 and the alignment key can be optically inspected and aligned from the outside of the donor substrate 100. The alignment mark 160 of the donor substrate 100 and the alignment key of the display panel can be inspected by disposing an optical inspection device 300 (e.g., a camera) outside the donor substrate 100.

[0105] Meanwhile, when aligning the donor substrate 100 and the display panel, the alignment key for secondary transfer transferred from the wafer 200 together with the plurality of LEDs 210 can be used instead of the alignment mark 160 of the donor substrate 100. The alignment key for secondary transfer is transferred to the donor substrate 100 together with the plurality of LEDs 210 and can be used to align the donor substrate 100 and the display panel. However, the donor substrate 100 and the display panel can be aligned by using the alignment mark 160 of the donor substrate 100 instead of the alignment key for secondary transfer, and the alignment method of the donor substrate 100 and the display panel is not limited thereto.

[0106] After the donor substrate 100 and the display panel are aligned, the donor substrate 100 and the display panel are combined in step S260 , and the plurality of LEDs 210 on the donor substrate 100 are transferred to the display panel in step S270 .

[0107] The donor substrate 100 and the display panel may be combined so that the plurality of LEDs 210 of the donor substrate 100 and the display panel face each other. In addition, the plurality of LEDs 210 may be shifted to correspond to a plurality of corresponding sub-pixels. Figures 1 to 2b As described above, the plurality of first protrusions 131 to which the plurality of LEDs 210 are attached can be arranged to correspond to the plurality of corresponding sub-pixels. Therefore, at least a portion of the plurality of LEDs 210 on one donor substrate 100 can be transferred to the display panel at once. Thus, by completing the transfer of the plurality of LEDs 210 from the donor substrate 100 to the substrate of the display panel, a display panel can be formed.

[0108] Conventionally, alignment protrusions are formed on a resin layer having viscoelasticity to align a donor substrate and a wafer or a donor substrate and a display panel. In this case, the alignment protrusions can be formed of the same material as the resin layer in a manner similar to the plurality of first protrusions and the plurality of second protrusions, and thus the alignment protrusions can be formed integrally with the resin layer. Therefore, the alignment protrusions can be formed of a material having a high transmittance, that is, can be formed to be substantially transparent. In addition, due to the characteristics of the viscoelastic polymer material constituting the alignment protrusions, the alignment protrusions can be formed to have a circular upper surface, so the edges of the alignment protrusions may not be clearly formed. In addition, during the transportation or processing of the donor substrate, the alignment protrusions may be easily deformed or damaged by external impact. Therefore, the edges of the alignment protrusions of conventional donor substrates are unclear or may be easily deformed or damaged, so that their position may change, resulting in defects such as an increase in the processing time for identifying the alignment protrusions or the occurrence of alignment errors.

[0109] In the following, reference will be made to Figures 7a to 7c Conventional alignment protrusions are described in more detail.

[0110] Figures 7a to 7c is an enlarged plan view of a donor substrate according to a comparative example. Figure 7a and Figure 7b is an image during the process of aligning the donor substrate and the wafer. Figure 7c is an image of the chip protrusion of the donor substrate. Compared with the donor substrate according to the exemplary embodiment of the present disclosure, the Figures 7a to 7c The donor substrate of the comparative example has a structure provided with alignment protrusions protruding from a resin layer, instead of forming alignment marks on the opposite surface of one surface of the substrate.

[0111] Reference Figure 7aand Figure 7b When aligning the donor substrate and the wafer, the alignment keys 220a and 220b of the wafer and the alignment protrusions 16a and 16b of the donor substrate are recognized, and based on this, the wafer and the donor substrate can be aligned.

[0112] In the case of the alignment keys 220a and 220b of the wafer, the alignment keys 220a and 220b are formed of a metal material having excellent reflectivity so that their edges can be clearly seen. Therefore, the optical inspection device 300 can easily identify the alignment keys 220a and 220b of the wafer, and as shown in FIG. Figure 7a and Figure 7b As shown, indicator lines 220aL and 220bL may be marked along the edges of the alignment keys 220a and 220b of the wafer.

[0113] Meanwhile, in the case of the alignment protrusions 16a and 16b of the donor substrate, their edges are somewhat unclear and can be easily confused with surrounding stains. Furthermore, when external force is applied to the resin layer of the donor substrate and the alignment protrusions 16a and 16b, such as when the donor substrate is bonded to a wafer, the resin layer is stretched, and the positions of the alignment protrusions 16a and 16b may be deformed or damaged. Therefore, due to the unclear edges, deformation, and damage to the alignment protrusions 16a and 16b, it is difficult to identify the alignment protrusions 16a and 16b in the optical inspection device 300.

[0114] For example, Figure 7a and Figure 7b As shown in FIG, the optical inspection device 300 cannot recognize the alignment protrusions 16a and 16b, so it can be confirmed that the indicator lines along the edges of the alignment protrusions 16a and 16b are not marked.

[0115] Reference Figure 7c , a plurality of chip protrusions 31c protruding from the resin layer are provided on the donor substrate so that a plurality of LEDs are temporarily adhered together with the alignment protrusions 16a and 16b. The chip protrusions 31c of the donor substrate according to the comparative example have substantially the same configuration as the first protrusion 131 of the donor substrate 100 according to the exemplary embodiment of the present disclosure. At this time, some of the plurality of chip protrusions 31c may be damaged due to external impact applied as the donor substrate is repeatedly used, and deformation of their edges can be seen, as shown in FIG. Figure 7c In addition, the alignment protrusions 16a and 16b protruding from the resin layer may be partially damaged and deformed due to external impact like the chip protrusion 31c. Therefore, when the alignment protrusions 16a and 16b are damaged, it may be difficult to identify the alignment protrusions 16a and 16b in the optical inspection device 300.

[0116] Therefore, in the donor substrate 100 according to the exemplary embodiment of the present disclosure, the alignment mark 160 is formed directly on the substrate 110, so that the deformation of the alignment mark 160 due to the stretching of the resin layer 130 or external impact can be reduced. Typically, alignment protrusions 16a and 16b formed of the same material as the resin layer are formed on the resin layer to align the donor substrate and the chip or the donor substrate and the display panel. However, since the resin layer is formed of a polymer material with viscoelasticity, when an external force is applied to the resin layer, such as in the bonding process of the donor substrate and the chip, the resin layer may be squeezed and stretched. As the resin layer stretches, the position of the alignment protrusions 16a and 16b also changes, so that the alignment accuracy of the donor substrate may be reduced. In addition, when the alignment protrusions 16a and 16b are formed of a polymer material such as the resin layer, the alignment protrusions 16a and 16b may be easily deformed or damaged due to external forces, etc. Furthermore, in the donor substrate 100 according to the exemplary embodiment of the present disclosure, since the alignment mark 160 is formed directly on the substrate 110 rather than on the resin layer 130, the position of the alignment mark 160 does not change even if the resin layer 130 is stretched. Furthermore, since the alignment mark 160 is formed by printing, laser engraving, or forming a metal material with excellent reflectivity on the surface of the substrate 110, the alignment mark 160 is less likely to deform or be damaged compared to the alignment protrusions 16a and 16b formed from conventional polymer materials. Therefore, in the donor substrate 100 according to the exemplary embodiment of the present disclosure, by forming the alignment mark 160 on the substrate 110 rather than on the resin layer 130, deformation of the alignment mark 160 caused by stretching of the resin layer 130 can be reduced, and the degree of alignment accuracy can be improved.

[0117] In the donor substrate 100 according to an exemplary embodiment of the present disclosure, by forming an alignment mark 160 having a low transmittance on a surface of the substrate 110 instead of the resin layer 130, the contrast between the alignment mark 160 and the remaining components of the donor substrate 100 can be increased, and the alignment mark 160 can be easily identified. The donor substrate 100 includes the substrate 110, the adhesive layer 120 disposed on one surface of the substrate 110, the resin layer 130, a plurality of first protrusions 131 and a plurality of second protrusions 132, and the alignment mark 160 formed on a surface opposite the one surface of the substrate 110. In this case, the alignment mark 160 can be configured to have a transmittance lower than the transmittance of the substrate 110, the adhesive layer 120, and the resin layer 130. For example, when forming the alignment mark 160 by a printing method, the alignment mark 160 can be formed by printing black ink. At the same time, the substrate 110, the adhesive layer 120, and the resin layer 130 can be formed of a material having a higher transmittance than the alignment mark 160 (i.e., a substantially transparent material). Therefore, the contrast between the alignment mark 160 and the remaining components of the donor substrate 100 can be improved. Therefore, during the primary transfer process or the secondary transfer process, the alignment mark 160 of the donor substrate 100 can be easily recognized, and the case where the alignment mark 160 of the donor substrate 100 is not recognized can be reduced. In the case where the alignment mark 160 of the donor substrate 100 is not recognized, such as Figure 3 and Figure 4 As shown, the process may return to the step of placing the donor substrate 100 into the processing equipment, potentially increasing processing time. Furthermore, due to the delayed pre-processing, post-processing may also be continuously delayed, and the time allocated to each process may be uneven, which may differ from the designed time. Therefore, in the donor substrate 100 according to the exemplary embodiment of the present disclosure, by forming the alignment mark 160 with a transmittance different from the transmittance of the remaining components of the donor substrate 100, the recognition rate of the alignment mark 160 can be increased, and the delay in processing time can also be reduced.

[0118] In the donor substrate 100 according to the exemplary embodiment of the present disclosure, since the alignment mark 160 is formed on a surface opposite to one surface of the substrate 110, the degree of flexibility in the manufacturing method and process of the alignment mark 160 is high. Specifically, the adhesive layer 120 and the resin layer 130 are provided on one surface of the substrate 110, and the surface opposite to the one surface of the substrate 110 is exposed to the outside. Furthermore, since the alignment mark 160 is formed on the surface opposite to the one surface of the substrate 110, there are no components that would hinder the formation of the alignment mark 160 on the opposite surface due to the external exposure of the alignment mark 160. Therefore, the degree of flexibility in the manufacturing method and process of the alignment mark 160 can be high. For example, when forming the alignment mark 160 on a previously used donor substrate 100, there is no need to perform steps such as separating the donor substrate 100. The alignment mark 160 can be easily formed simply by printing, irradiating the donor substrate 100 with a laser, or coating the donor substrate 100 with a material having excellent reflectivity. Therefore, in the donor substrate 100 according to the exemplary embodiment of the present disclosure, since the alignment mark 160 is formed on the relative surface exposed to the outside of one surface of the substrate 110, the obstacles to the formation of the alignment mark 160 can be reduced, and the degree of freedom of the manufacturing method and process of the alignment mark 160 can be higher.

[0119] Figure 8 is an enlarged rear view of a donor substrate according to another exemplary embodiment of the present disclosure. Figure 8 The donor substrate 800 and Figures 1 to 6 The donor substrate 100 is different only in the shape of the alignment mark 860, but the other configurations thereof are substantially the same, and thus repeated description will be omitted.

[0120] Reference Figure 8 The alignment mark 860 of the donor substrate 800 may include at least one hole 861 disposed inside the edge thereof. The alignment mark 860 may be formed in a form in which the inside of the edge is hollow. For example, the alignment mark 860 of the donor substrate 800 may have a donut-shaped shape having the hole 861 formed in the center thereof, such as a ring.

[0121] When the alignment mark 860 of the donor substrate 800 includes one or more holes 861, the alignment key 220′ of the wafer 200 can be identified through the holes 861. The edge of the alignment key 220′ of the wafer 200 can be disposed within the hole 861. For example, the alignment key 220′ of the wafer 200 can have a size smaller than the hole 861 of the alignment mark 860 and can be disposed within the hole 861 of the alignment mark 860.

[0122] However, even when the alignment mark 860 of the donor substrate 800 includes one or more holes 861, the alignment key 220' of the wafer 200 may have a diameter greater than that of the substrate 800. Figure 6 The alignment mark 860 may have a size as shown in FIG, and may be formed in a ring shape surrounding the alignment mark 860, but is not limited thereto.

[0123] In a donor substrate 800 according to another exemplary embodiment of the present disclosure, the shape of the alignment mark 860 can be configured differently, taking into account the alignment key 220' of the wafer 200, the alignment key of the display panel, or an optical inspection method. The alignment mark 860 of the donor substrate 800 can be aligned with the alignment key 220' of the wafer 200 or the alignment key of the display panel. In this case, in order to facilitate the alignment of the alignment mark 860 with the alignment key 220' of the wafer 200 or the alignment key of the display panel, the shape of the alignment mark 860 can be configured differently. For example, when the alignment key 220' of the wafer 200 is formed so that its interior has an opaque circular shape, the alignment mark 860 of the donor substrate 800 can be formed into a circular shape with a hole 861 formed therein. In addition, the wafer 200 and the donor substrate 800 can be aligned so that the alignment key 220' is disposed within the hole 861. Therefore, in the donor substrate 800 according to another exemplary embodiment of the present disclosure, by forming the alignment mark 860 in consideration of the alignment key 220' of the wafer 200, the alignment key of the display panel, or an optical inspection method, the alignment of the donor substrate 800 and the wafer 200 and the donor substrate 800 and the display panel can be facilitated.

[0124] Figure 9 is a cross-sectional view of a donor substrate according to yet another exemplary embodiment of the present disclosure. Figure 9 The donor substrate 900 and Figures 1 to 6 The donor substrate 100 is different only in the arrangement of the alignment mark 960, but the other configurations thereof are substantially the same, and thus repeated description will be omitted.

[0125] Reference Figure 9 , the alignment mark 960 is formed on one surface of the substrate 110. The alignment mark 960 is provided between the substrate 110 and the adhesive layer 120. The alignment mark 960 formed on one surface of the substrate 110 may be covered by the adhesive layer 120 and the resin layer 130. At this time, since the adhesive layer 120 and the resin layer 130 are formed on the one surface of the substrate 110 on which the alignment mark 960 is formed, the upper portion of the one surface of the substrate 110 may be planarized.

[0126] However, even when the adhesive layer 120 is omitted, the upper portion of one surface of the substrate 110 can be planarized because the material constituting the resin layer 130 is coated on one surface of the substrate 110 where the alignment mark 960 is formed and then the resin layer 130 is formed by curing the material.

[0127] In a donor substrate 900 according to another exemplary embodiment of the present disclosure, alignment marks 960 are formed on one surface of the substrate 110 where the resin layer 130 is to be disposed, thereby reducing the reduction in thickness uniformity caused by the alignment marks 960. Alignment marks 960 can be formed by printing, laser engraving, or by forming a material having excellent reflectivity on one surface of the substrate 110. However, when alignment marks 960 are formed by irradiating a laser onto the substrate 110 and performing engraving, burrs are generated in the alignment marks 960, causing one surface of the substrate 110 to be uneven and potentially rough. Such burrs may reduce the flatness of the substrate 110 and the thickness uniformity of the resin layer 130 on one surface of the substrate 110, thereby potentially shifting the positions of the plurality of first protrusions 131 and the plurality of second protrusions 132. Furthermore, the alignment accuracy between the donor substrate 900 and the wafer 200, or between the donor substrate 900 and the display panel, may also be reduced. Meanwhile, in the donor substrate 900 according to another exemplary embodiment of the present disclosure, the adhesive layer 120 and / or the resin layer 130 are applied and cured on one surface of the substrate 110 on which the alignment mark 960 is formed, so that the upper portion of the substrate 110 can be flattened. Therefore, in the donor substrate 900 according to another exemplary embodiment of the present disclosure, the adhesive layer 120 and / or the resin layer 130 are provided to cover the alignment mark 960, thereby improving the thickness uniformity of the resin layer 130 and improving the alignment accuracy during the transfer process while the surface of the substrate 110 is flat.

[0128] In a donor substrate 900 according to another exemplary embodiment of the present disclosure, the adhesive layer 120 and / or the resin layer 130 may be provided to cover the alignment mark 960, thereby reducing damage to the alignment mark 960. The donor substrate 900 formed with the alignment mark 960 can be reused in both the primary and secondary transfer processes. That is, the donor substrate 900 can be reused to perform both the primary and secondary transfer processes. During such handling or transfer processes, the donor substrate 900 may come into contact with external components and cause scratches, etc. However, in the donor substrate 900 according to another exemplary embodiment of the present disclosure, since the adhesive layer 120 and / or the resin layer 130 are provided to cover the alignment mark 960, the alignment mark 960 is prevented from coming into contact with external components. Therefore, according to another exemplary embodiment of the present disclosure, since the adhesive layer 120 and / or the resin layer 130 are formed to cover the alignment mark 960 in the donor substrate 900, damage to the alignment mark 960, such as scratches, caused by repeated use of the donor substrate 900 can be reduced.

[0129] Exemplary embodiments of the present disclosure can also be described as follows:

[0130] According to one aspect of the present disclosure, a donor substrate is provided, comprising: a substrate; a resin layer disposed on one surface of the substrate; a plurality of first protrusions on the resin layer; and an alignment mark disposed on a surface of the substrate.

[0131] The alignment mark may be provided on a surface opposite to one surface of the substrate.

[0132] The alignment mark may be provided on one surface of the substrate.

[0133] The donor substrate may further include an adhesive layer disposed between the resin layer and the substrate. The alignment mark may be in contact with the adhesive layer.

[0134] The resin layer may include an active region provided with a plurality of first protrusions and a barrier region surrounding the active region. The donor substrate may further include a plurality of second protrusions provided in the barrier region.

[0135] The height of the plurality of second protrusions may be the same as the height of the plurality of first protrusions.

[0136] The alignment mark may be provided on a remaining portion of the substrate surface excluding a portion overlapping with the plurality of first protrusions and the plurality of second protrusions.

[0137] The substrate may include a transfer region overlapping the resin layer and a non-transfer region protruding outside the resin layer. The donor substrate may further include an identification pattern provided on the non-transfer region and a direction pattern provided in the non-transfer region.

[0138] Alignment marks may be provided in the transfer area.

[0139] The substrate and the resin layer may be formed of a transparent material, and the alignment mark may be formed of an opaque material.

[0140] According to another aspect of the present disclosure, there is a method for transferring LEDs. The method includes aligning a wafer and a donor substrate, and transferring a plurality of LEDs on the wafer to the donor substrate. The donor substrate includes a substrate marked with an alignment mark, a resin layer on the substrate, and a plurality of first protrusions protruding from the resin layer. The wafer and the donor substrate are aligned by aligning the alignment mark on the donor substrate with the alignment key on the wafer.

[0141] The alignment mark may be provided to overlap with the resin layer on a surface that is in contact with the resin layer among the plurality of surfaces of the substrate.

[0142] The alignment mark may be provided to overlap the resin layer on a surface opposite to a surface in contact with the resin layer among the plurality of surfaces of the substrate.

[0143] The substrate and the resin layer may be formed of a material having a transmittance higher than that of the alignment mark. Also, the alignment of the wafer and the donor substrate may be performed by optically inspecting the alignment mark and the alignment key outside the donor substrate or outside the wafer.

[0144] An edge of the alignment mark may overlap an inner portion of the alignment key.

[0145] The alignment mark may include at least one hole, and an edge of the alignment key may overlap an interior of the at least one hole.

[0146] Transferring the plurality of LEDs to the donor substrate may include transferring the plurality of LEDs onto upper surfaces of the plurality of first protrusions.

[0147] The donor substrate may further include a plurality of second protrusions protruding from the resin layer. In a process of transferring the plurality of LEDs to the donor substrate, the plurality of LEDs may be spaced apart from the plurality of second protrusions.

[0148] The LED transfer method may further include aligning the donor substrate to which the plurality of LEDs have been transferred and the display panel, and transferring the plurality of LEDs transferred to the donor substrate to the display panel. Aligning the donor substrate and the display panel may include aligning an alignment mark of the donor substrate with an alignment key of the display panel.

[0149] Although the exemplary embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the present disclosure is not limited thereto and can be implemented in many different forms without departing from the technical concepts of the present disclosure. Therefore, the exemplary embodiments of the present disclosure are provided for illustrative purposes only and are not intended to limit the technical concepts of the present disclosure. The scope of the technical concepts of the present disclosure is not limited thereto. Therefore, it should be understood that the above exemplary embodiments are illustrative in all aspects and do not limit the present disclosure. The scope of protection of the present disclosure should be interpreted based on the attached claims, and all technical concepts within their equivalent scope should be interpreted as falling within the scope of the present disclosure.

Claims

1. A donor substrate comprising: substrate; a resin layer disposed on the substrate; a plurality of first protrusions on the resin layer; as well as alignment marks provided on the surface of the substrate, Wherein, the resin layer comprises: an effective area in which the plurality of first protrusions are provided; and a barrier region located outside the active region and surrounding the active region, Wherein, the donor substrate further includes a plurality of second protrusions arranged in the barrier region, Wherein, the substrate comprises: a transfer region overlapping the resin layer; and a non-transfer region protruding outside the resin layer, and Wherein, the alignment mark is arranged in the transfer area.

2. The donor substrate according to claim 1, wherein The alignment mark is provided on a surface of the substrate opposite to one surface on which the resin layer is provided.

3. The donor substrate according to claim 1, wherein The alignment mark is provided on one surface of the substrate where the resin layer is provided.

4. The donor substrate according to claim 3, further comprising: an adhesive layer provided between the resin layer and the substrate, Wherein, the alignment mark contacts the adhesive layer.

5. The donor substrate according to claim 1, wherein The height of the second protrusions is the same as that of the first protrusions. The donor substrate according to claim 2 , wherein: The plurality of second protrusions are configured to reduce deformation of the donor substrate, and the alignment mark is provided on a remaining portion of the surface of the substrate except for a portion overlapping with the plurality of first protrusions and the plurality of second protrusions, such that the plurality of second protrusions do not overlap with the alignment mark.

7. The donor substrate according to claim 1, in, The donor substrate further comprises: an identification pattern disposed on the non-transfer area; and A directional pattern is provided in the non-transfer area.

8. The donor substrate according to claim 1, wherein The substrate and the resin layer are formed of a transparent material, Wherein, the alignment mark is formed of an opaque material.

9. A method for transferring LEDs, comprising the following steps: aligning the wafer and the donor substrate; as well as transferring the plurality of LEDs on the wafer to the donor substrate, Wherein, the donor substrate comprises: a substrate having alignment marks marked thereon; a resin layer located on the substrate; and a plurality of first protrusions protruding from the resin layer, and The step of aligning the wafer and the donor substrate is to align the alignment mark of the donor substrate with the alignment key of the wafer. Wherein, the resin layer comprises: an effective area in which the plurality of first protrusions are provided; and a barrier region located outside the active region and surrounding the active region, Wherein, the donor substrate further includes a plurality of second protrusions arranged in the barrier region, Wherein, the substrate comprises: a transfer region overlapping the resin layer; and a non-transfer region protruding outside the resin layer, and Wherein, the alignment mark is arranged in the transfer area.

10. The LED transfer method according to claim 9, wherein: The alignment mark is provided to overlap with the resin layer on a surface that is in contact with the resin layer among the plurality of surfaces of the substrate.

11. The LED transfer method according to claim 9, wherein: The alignment mark is provided to overlap the resin layer on a surface opposite to a surface in contact with the resin layer among the plurality of surfaces of the substrate.

12. The LED transfer method according to claim 9, wherein: The substrate and the resin layer are formed of a material having a transmittance higher than that of the alignment mark, and The step of aligning the wafer and the donor substrate is to optically inspect the alignment mark of the donor substrate and the alignment key of the wafer from the outside of the donor substrate or the outside of the wafer.

13. The LED transfer method according to claim 12, wherein: An edge of the alignment mark overlaps an inner portion of the alignment key.

14. The LED transfer method according to claim 12, wherein: The alignment mark includes at least one hole, and Wherein, an edge of the alignment key overlaps with an interior of the at least one hole.

15. The LED transfer method according to claim 9, wherein: The step of transferring the plurality of LEDs to the donor substrate includes transferring the plurality of LEDs onto upper surfaces of the plurality of first protrusions.

16. The LED transfer method according to claim 15, wherein: The plurality of second protrusions protrude from the resin layer, and Wherein, in the step of transferring the plurality of LEDs to the donor substrate, the plurality of LEDs are spaced apart from the plurality of second protrusions.

17. The LED transfer method according to claim 9, further comprising the following steps: aligning the donor substrate to which the plurality of LEDs have been transferred with a display panel; as well as transferring the plurality of LEDs transferred to the donor substrate to the display panel, The step of aligning the donor substrate and the display panel includes aligning the alignment mark of the donor substrate with an alignment key of the display panel.

Images