Transfer film for micro LED laser transfer substrate and micro LED transfer apparatus and method using the same

Abstract

A transfer film for a micro LED laser transfer substrate comprises a first release film, a point adhesive layer located on the first release film, a functional layer located on the point adhesive layer and composed of a buffer material that hardens and undergoes ablation when absorbing a laser or a dynamic release material that deforms and swells when absorbing a laser, and a second release film located on the functional layer, wherein the first release film and the second release film support the point adhesive layer and the functional layer so that the point adhesive layer and the functional layer can be formed and maintained at a predetermined thickness.

Description

Technology Field

[0001] The present invention relates to a transfer film for a micro LED laser transfer substrate and a micro LED transfer apparatus and method using the same, and more specifically, to a transfer film for a carrier substrate on which a micro LED is transferred from an epi wafer and a micro LED transfer apparatus and method using the same. Background Technology

[0002] Micro LED displays are next-generation light-emitting displays that use very small LEDs, ranging from 10 to 100 micrometers in size, as pixel light sources. Micro LED displays can precisely display screen brightness and color by individually controlling multiple micro LEDs arranged in the display area, and because they use inorganic semiconductors, there is no need to worry about image degradation or burn-in, which leaves afterimages.

[0003] Among the processes for manufacturing micro LED displays, there is a transfer process in which micro LEDs are moved from an epi wafer, on which micro LEDs are formed, to a backplane. The transfer process must be able to accurately transfer three colors of micro LEDs to the backplane after aligning them according to the pixel arrangement method. In the case of recently commercialized 8K TVs, approximately 100 million micro LEDs are required, and the transfer process for moving such a large number of micro LEDs to the backplane takes a very long time.

[0004] The transfer process is performed by transferring a plurality of micro LEDs formed on an epi wafer to a carrier substrate, transferring the plurality of micro LEDs transferred to the carrier substrate to an interposer substrate in accordance with the pixel arrangement method of the micro LED display, and transferring the plurality of micro LEDs transferred to the interposer substrate to a back plane of the micro LED display.

[0005] At this time, the carrier substrate is manufactured by forming a coating film by spin-coating a liquid buffer material that hardens when a laser is irradiated onto a transparent substrate such as quartz or sapphire, or a dynamic release material that deforms when a laser is irradiated.

[0006] However, for the manufacturing of large-scale micro LED displays, the carrier substrate needs to be enlarged, and as the carrier substrate becomes larger, difficulties in the coating process and uniformity issues regarding the thickness of the coating film may arise.

[0007] In addition, carrier substrates formed with a coating film by spin coating have the problem that they can only be used once, and that they can be recycled only after removing the remaining coating film through chemical cleaning after use.

[0009] [Research and development projects that supported this invention]

[0010] [Project ID]

[0011] [Project No.] E2424003

[0012] [Ministry Name] Gyeonggi-do

[0013] [Specialized Research Management Agency] Gyeonggi Economic & Science Promotion Agency

[0014] [Project Name] 2024 Gyeonggi-do Materials, Parts, and Equipment Enterprise Development Support Program

[0015] [Project Title] Development of High-Performance Silicon Adhesive Film for u-LED Mass Transfer Substrates

[0016] [Organizing Agency] LCTEC Co., Ltd.

[0017] [Research Period] June 3, 2024 ~ November 29, 2024 The problem to be solved

[0019] The technical problem that the present invention aims to solve is to provide a transfer film for a micro LED laser transfer substrate, and a micro LED transfer apparatus and method using the same, which can ensure thickness uniformity of the coating film on a carrier substrate and allow the coating film to be easily removed by a physical method without chemical cleaning. means of solving the problem

[0020] A transfer film for a micro LED laser transfer substrate according to one embodiment of the present invention comprises a first release film, a point adhesive layer located on the first release film, a functional layer located on the point adhesive layer and composed of a buffer material that hardens and undergoes ablation when absorbing a laser or a dynamic release material that deforms and swells when absorbing a laser, and a second release film located on the functional layer, wherein the first release film and the second release film support the point adhesive layer and the functional layer so that the point adhesive layer and the functional layer can be formed and maintained at a predetermined thickness.

[0021] The above functional layer may include a composite material of polyimide and neodymium-based butadiene rubber.

[0022] A transfer film for a micro LED laser transfer substrate according to another embodiment of the present invention comprises a first release film, a pressure-adhesive layer located on the first release film, a substrate layer located on the pressure-adhesive layer, a high-elasticity pressure-adhesive layer located on the substrate layer and composed of a buffer material that hardens and undergoes ablation when absorbing a laser or a dynamic release material that deforms and swells when absorbing a laser, and a second release film located on the high-elasticity pressure-adhesive layer, wherein the first release film and the second release film support the pressure-adhesive layer and the high-elasticity pressure-adhesive layer so that the pressure-adhesive layer and the high-elasticity pressure-adhesive layer can be formed and maintained at a predetermined thickness.

[0023] The above substrate layer supports the high-elasticity adhesive layer and improves the physical strength of the transfer film itself, thereby reducing the degree of bending.

[0024] A micro LED transfer device according to another embodiment of the present invention comprises a first transfer unit for transferring a plurality of micro LEDs formed on an epi wafer to a carrier substrate, a second transfer unit for aligning the plurality of micro LEDs according to a pixel arrangement method and transferring them to an interposer substrate, a bonding unit for transferring a plurality of micro LEDs from the interposer substrate to a backplane, and a carrier substrate providing unit for providing the carrier substrate, on which a transfer film is laminated to a transparent substrate, to the first transfer unit, wherein the transfer film comprises a first release film, a point adhesive layer located on the first release film, a functional layer located on the point adhesive layer, and a second release film located on the functional layer, wherein the carrier substrate providing unit physically separates and removes the first release film from the point adhesive layer and performs lamination to attach the point adhesive layer to the upper surface of the transparent substrate to produce a preliminary carrier substrate.

[0025] The carrier substrate providing unit can produce the carrier substrate by physically separating and removing the second release film from the functional layer in the preliminary carrier substrate.

[0026] In the above-mentioned preliminary carrier substrate, the second release film can cover the functional layer to protect the functional layer from external contamination or physical impact.

[0027] The carrier substrate providing unit may store the spare carrier substrate in a separate storage space, and upon a request from the first transfer unit, retrieve the spare carrier substrate from the storage space and remove only the second release film to provide the carrier substrate to the first transfer unit.

[0028] The above functional layer may be made of a buffer material that hardens and ablates when it absorbs a laser, or a dynamic release material that deforms and swells when it absorbs a laser.

[0029] The above functional layer comprises a substrate layer located on the adhesive layer and a high-elasticity adhesive layer located on the substrate layer, and the high-elasticity adhesive layer may be made of a buffer material that hardens and causes ablation when it absorbs a laser, or a dynamic release material that deforms and swells when it absorbs a laser.

[0030] A micro LED transfer method according to another embodiment of the present invention comprises the steps of: producing a carrier substrate in which a transfer film is laminated to a transparent substrate; transferring a plurality of micro LEDs formed on an epi wafer to the carrier substrate; aligning the plurality of micro LEDs according to a pixel arrangement method and transferring them to an interposer substrate; and transferring a plurality of micro LEDs from the interposer substrate to a backplane. The transfer film comprises a first release film, a point adhesive layer located on the first release film, a functional layer located on the point adhesive layer, and a second release film located on the functional layer. A preliminary carrier substrate is produced by physically separating and removing the first release film from the point adhesive layer and performing lamination to attach the point adhesive layer to the upper surface of the transparent substrate, and the carrier substrate is produced by physically separating and removing the second release film from the functional layer on the preliminary carrier substrate.

[0031] In the above-mentioned preliminary carrier substrate, the second release film can cover the functional layer to protect the functional layer from external contamination or physical impact.

[0032] The above-mentioned preliminary carrier substrate can be stored in a separate storage space, and the preliminary carrier substrate can be taken from the storage space and the carrier substrate can be provided by removing only the second release film.

[0033] The above functional layer may be made of a buffer material that hardens and ablates when it absorbs a laser, or a dynamic release material that deforms and swells when it absorbs a laser.

[0034] The above functional layer comprises a substrate layer located on the adhesive layer and a high-elasticity adhesive layer located on the substrate layer, and the high-elasticity adhesive layer may be made of a buffer material that hardens and causes ablation when it absorbs a laser, or a dynamic release material that deforms and swells when it absorbs a laser. Effects of the invention

[0035] The transfer film for a micro LED laser transfer substrate according to an embodiment of the present invention, and the micro LED transfer device and method using the same, can ensure thickness uniformity of the coating film on a carrier substrate and allow the coating film to be easily removed by a physical method without chemical cleaning. Brief explanation of the drawing

[0036] FIG. 1 is a cross-sectional view showing a transfer film for a micro LED laser transfer substrate according to one embodiment of the present invention. FIG. 2 is a cross-sectional view showing a transfer film for a micro LED laser transfer substrate according to another embodiment of the present invention. FIG. 3 is a block diagram showing a micro LED transfer device according to one embodiment of the present invention. FIG. 4 is a flowchart illustrating the process of fabricating a carrier substrate using a transfer film according to one embodiment of the present invention. FIGS. 5 to 8 are cross-sectional views illustrating the process of manufacturing a carrier substrate using a transfer film according to an embodiment of the present invention. Figure 9 is a cross-sectional view showing an epi wafer for manufacturing a micro LED display. FIGS. 10 to 12 are cross-sectional views illustrating a micro LED transfer method according to an embodiment of the present invention. Specific details for implementing the invention

[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0038] In addition, in various embodiments, components having the same configuration are described representatively in the first embodiment using the same reference numerals, and in other embodiments, only configurations different from the first embodiment are described.

[0039] To clearly explain the present invention, parts unrelated to the explanation have been omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0040] The size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and therefore the present invention is not necessarily limited to what is illustrated. Thicknesses have been enlarged in the drawings to clearly represent various layers and regions. Additionally, for convenience of explanation, the thickness of some layers and regions has been exaggerated in the drawings.

[0041] When a part such as a layer, membrane, region, or plate is said to be "on" or "on" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Furthermore, being "on" or "on" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "on" in the direction opposite to gravity.

[0042] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0043] Throughout the specification, "planar" means the subject part as viewed from above, and "cross-sectional" means the cross-section obtained by vertically cutting the subject part as viewed from the side.

[0044] FIG. 1 is a cross-sectional view showing a transfer film for a micro LED laser transfer substrate according to one embodiment of the present invention.

[0045] Referring to FIG. 1, a transfer film (410) for a micro LED laser transfer substrate according to one embodiment of the present invention may include a first releasing film (411), an adhesive layer (412), a functional layer (413), and a second releasing film (414).

[0046] A pressure-adhesive layer (412) may be positioned on the first release film (411), a functional layer (413) may be positioned on the pressure-adhesive layer (412), and a second release film (414) may be positioned on the functional layer (413). That is, a pressure-adhesive layer (412) and a functional layer (413) that form a carrier substrate (see 110 in FIG. 8) to be described later are formed between the first release film (411) and the second release film (414). Since the pressure-adhesive layer (412) and the functional layer (413) are formed between the first release film (411) and the second release film (414), the pressure-adhesive layer (412) and the functional layer (413) can be formed with a predetermined uniform thickness.

[0047] The adhesive layer (412) is intended to attach a functional layer (413) to a transparent substrate (see 101 in FIG. 8) during the process of manufacturing the carrier substrate (110). The adhesive layer (412) may be made of a transparent polymer having adhesive properties, such as silicone, acrylic, epoxy, PDMS (polydimethylsiloxane), or urethane. The thickness of the adhesive layer (412) may be 1 to 50 μm.

[0048] The functional layer (413) may be composed of a buffer material that can absorb a laser and hardens to cause ablation when it absorbs the laser, or a dynamic release material that deforms and swells when it absorbs the laser. The functional layer (413) may include a composite material of polyimide and neodymium-based butadiene rubber (NdBR). The thickness of the functional layer (413) may be 1 to 50 μm.

[0049] The first release film (411) may be made of a material that can be physically easily separated from the adhesive layer (412), and the second release film (414) may be made of a material that can be physically easily separated from the functional layer (413). The first release film (411) and the second release film (414) may support the adhesive layer (412) and the functional layer (413) so that the adhesive layer (412) and the functional layer (413) can be formed and maintained at a predetermined uniform thickness.

[0050] Hereinafter, a transfer film (410) according to another embodiment of the present invention will be described with reference to FIG. 2. The description will focus on the differences compared with the embodiment of FIG. 1.

[0051] FIG. 2 is a cross-sectional view showing a transfer film for a micro LED laser transfer substrate according to another embodiment of the present invention.

[0052] Referring to FIG. 2, a transfer film (410) for a micro LED laser transfer substrate according to another embodiment of the present invention may include a first release film (411), a pressure-adhesive layer (412), a functional layer (413) comprising a substrate layer (413-1) and a high-elasticity pressure-adhesive layer (413-2), and a second release film (414). The pressure-adhesive layer (412) may be positioned on the first release film (411), the substrate layer (413-1) may be positioned on the pressure-adhesive layer (412), the high-elasticity pressure-adhesive layer (413-2) may be positioned on the substrate layer (413-1), and the second release film (414) may be positioned on the high-elasticity pressure-adhesive layer (413-2).

[0053] The difference is that in the embodiment of FIG. 1, the functional layer (413) is formed as a single layer structure, whereas in the embodiment of FIG. 2, the functional layer (413) is formed as a two-layer structure consisting of a substrate layer (413-1) and a high-elasticity adhesive layer (413-2).

[0054] The adhesive layer (412) can attach the substrate layer (413-1) to the transparent substrate (101) during the process of manufacturing the carrier substrate (110).

[0055] The substrate layer (413-1) can support the high-elasticity adhesive layer (413-2) and improve the physical strength of the transfer film (410) itself. For the manufacture of a large micro LED display, the carrier substrate (110) must be enlarged, and the transfer film (410) used in the production of the carrier substrate (110) must also be enlarged. If the transfer film (410) is enlarged, it can easily bend, which may cause mis-attachment to the transparent substrate (101) or deformation of the thickness of the functional layer (413) during the production process of the carrier substrate (110). The substrate layer (413-1) can reduce the degree of bending of the transfer film (410) and prevent mis-attachment or deformation of the thickness of the functional layer (413) by improving the physical strength of the transfer film (410) itself. The substrate layer (413-1) can be made of polyimide, which has excellent chemical stability and physical strength.

[0056] The high-elasticity adhesive layer (413-2) can be made of a buffer material that can absorb a laser and hardens and causes ablation when it absorbs the laser, or a dynamic release material that deforms and swells when it absorbs the laser.

[0057] The first release film (411) may be made of a material that can be physically easily separated from the adhesive layer (412), and the second release film (414) may be made of a material that can be physically easily separated from the high-elasticity adhesive layer (413-2). The first release film (411) and the second release film (414) may support the adhesive layer (412) and the high-elasticity adhesive layer (413-2) so that the adhesive layer (412) and the high-elasticity adhesive layer (413-2) can be formed and maintained at a predetermined uniform thickness.

[0058] Hereinafter, a micro LED transfer apparatus and method according to an embodiment of the present invention will be described with reference to FIGS. 3 to 12.

[0059] FIG. 3 is a block diagram showing a micro LED transfer apparatus according to an embodiment of the present invention. FIG. 4 is a flowchart showing a process of fabricating a carrier substrate using a transfer film according to an embodiment of the present invention. FIG. 5 to 8 are cross-sectional views illustrating a process of fabricating a carrier substrate using a transfer film according to an embodiment of the present invention. FIG. 9 is a cross-sectional view showing an epi wafer for manufacturing a micro LED display. FIG. 10 to 12 are cross-sectional views illustrating a micro LED transfer method according to an embodiment of the present invention.

[0060] Referring to FIGS. 3 to 12, the micro LED transfer device (1000) may include a first transfer unit (100), a second transfer unit (200), a bonding unit (300), and a carrier substrate providing unit (400).

[0061] An epi wafer and a carrier substrate (110) are loaded into the first transfer unit (100). A plurality of micro LEDs for forming pixels of a micro LED display are formed on the epi wafer. The carrier substrate (110) can be manufactured in a carrier substrate providing unit (400) and provided to the first transfer unit (100).

[0062] A transparent substrate (101) and a transfer film (410) are loaded into a carrier substrate providing unit (400), and the carrier substrate providing unit (400) can perform a process of aligning the transparent substrate (101) and the transfer film (410) facing each other (S110). The first release film (411) of the transfer film (410) faces the upper surface of the transparent substrate (101). The transfer film (410) can be formed in a structure according to either embodiment of FIG. 1 or FIG. 2.

[0063] The carrier substrate providing unit (400) can perform the process of removing the first release film (411) and laminating the transfer film (410) onto the transparent substrate (101) (S120). As illustrated in FIG. 5, the carrier substrate providing unit (400) can physically separate and remove the first release film (411) from the transfer film (410) from the adhesive layer (412). And as illustrated in FIG. 6, the carrier substrate providing unit (400) can perform laminating by attaching the adhesive layer (412) of the transfer film (410) to the upper surface of the transparent substrate (101). That is, the carrier substrate providing unit (400) can produce a preliminary carrier substrate (110') comprising a transparent substrate (101), a spot adhesive layer (412) located on the transparent substrate (101), a functional layer (413) located on the spot adhesive layer (412), and a second release film (414) located on the functional layer (413).

[0064] Next, the carrier substrate providing unit (400) can perform the process of producing a laser transfer carrier substrate (110) by removing the second release film (414) (S130). As illustrated in FIG. 7, the carrier substrate providing unit (400) can physically separate and remove the second release film (414) from the functional layer (413) from the preliminary carrier substrate (110'). And as illustrated in FIG. 8, the carrier substrate providing unit (400) can produce a carrier substrate (110) including a transparent substrate (101) from which the second release film (414) has been removed, a spot adhesive layer (412) located on the transparent substrate (101), and a functional layer (413) located on the spot adhesive layer (412). The carrier substrate providing unit (400) can provide the produced carrier substrate (110) to the first transfer unit (100).

[0065] Meanwhile, since the second release film (414) covers the functional layer (413) on the preliminary carrier substrate (110'), the functional layer (413) can be protected from external contamination or physical impact. That is, the second release film (414) can protect the functional layer (413) of the preliminary carrier substrate (110') from external contamination or physical impact. The carrier substrate providing unit (400) can manufacture these preliminary carrier substrates (110') in large quantities and stockpile them in a separate storage space, and when the production of the carrier substrate (110) is required (or at the request of the first transfer unit (100), the preliminary carrier substrate (110') can be taken from the storage space, and only the second release film (414) can be removed to provide the carrier substrate (110) to the first transfer unit (100). In this case, the carrier substrate providing unit (400) can omit the process of removing the first release film (411) and laminating the transfer film (410) onto the transparent substrate (101) when providing the carrier substrate (110), and can quickly produce the carrier substrate (110) and provide it to the first transfer unit (100).

[0066] In another embodiment, the carrier substrate providing unit (400) may manufacture a large quantity of spare carrier substrates (110') and store them in a separate storage space, and then provide the spare carrier substrates (110') to the first transfer unit (100) upon the request of the first transfer unit (100), and the first transfer unit (100) may remove the second release film (414) of the spare carrier substrate (110') to use it as a carrier substrate (110). In this case, contamination or damage to the carrier substrate (110) caused by external contamination or physical impact that may occur during the process of providing the carrier substrate (110) to the first transfer unit (100) can be prevented.

[0067] Now, I will explain the overall process of transferring micro LEDs.

[0068] As illustrated in FIG. 9, the epi wafer may include a first color epi wafer (10), a second color epi wafer (20), and a third color epi wafer (30). Micro LEDs that emit different colors among primary colors are formed in the first color epi wafer (10), the second color epi wafer (20), and the third color epi wafer (30). Examples of primary colors include the three primary colors of red, green, and blue. For example, the first color epi wafer (10) may include a plurality of first micro LEDs (12) formed on a wafer (11) to emit red light. The second color epi wafer (20) may include a plurality of second micro LEDs (22) formed on a wafer (21) to emit green light. The third color epi wafer (30) may include a plurality of third micro LEDs (32) formed on the wafer (31) to emit blue light. The wafers (11, 21, 31) may be sapphire wafers.

[0069] The first transfer unit (100) can perform the process of transferring a plurality of micro LEDs formed on an epi wafer to a carrier substrate (110).

[0070] As illustrated in FIG. 10, the carrier substrate (110) may include a first color carrier substrate (110-1) on which a plurality of first micro LEDs (12) are transferred, a second color carrier substrate (110-2) on which a plurality of second micro LEDs (22) are transferred, and a third color carrier substrate (110-3) on which a plurality of third micro LEDs (32) are transferred. The first transfer unit (100) may transfer a plurality of first micro LEDs (12) from a first color epi wafer (10) to the first color carrier substrate (110-1). And the first transfer unit (100) may transfer a plurality of second micro LEDs (22) from a second color epi wafer (20) to the second color carrier substrate (110-2). And the first transfer unit (100) can transfer a plurality of third micro LEDs (32) from a third color epi wafer (30) to a third color carrier substrate (110-3). At this time, the first transfer unit (100) can separate a plurality of first micro LEDs (12), a plurality of second micro LEDs (22) and a plurality of third micro LEDs (32) from the wafer (11, 21, 31) by a laser lift-off (LLO) method that removes an insulating film using a laser. For example, the first transfer unit (100) can transfer all first micro LEDs (12) formed on the first color epi wafer (10) to the first color carrier substrate (110-1) at once using the LLO method, transfer all second micro LEDs (22) formed on the second color epi wafer (20) to the second color carrier substrate (110-2) at once, and transfer all third micro LEDs (32) formed on the third color epi wafer (30) to the third color carrier substrate (110-3) at once.The first transfer unit (100) can load a first color carrier substrate (110-1) on which a plurality of first micro LEDs (12) are transferred, a second color carrier substrate (110-2) on which a plurality of second micro LEDs (22) are transferred, and a third color carrier substrate (110-3) on which a plurality of third micro LEDs (32) are transferred, into the second transfer unit (200).

[0071] An interposer substrate (210) is loaded into the second transfer unit (200). The interposer substrate (210) is intended to align a plurality of first micro LEDs (12), a plurality of second micro LEDs (22), and a plurality of third micro LEDs (32) according to the pixel arrangement method of the micro LED display. The second transfer unit (200) can perform the process of aligning a plurality of first micro LEDs (12), a plurality of second micro LEDs (22), and a plurality of third micro LEDs (32) according to the pixel arrangement method and transferring them to the interposer substrate (210).

[0072] The pixel arrangement method of a micro LED display may include a method in which red pixels (first micro LED), green pixels (second micro LED), and blue pixels (third micro LED) are repeatedly arranged in a row direction on a plane, and red pixels are continuously arranged in the direction of one column, green pixels are continuously arranged in the direction of the next column, and blue pixels are continuously arranged in the direction of the next column. In addition, the pixel arrangement method of a micro LED display may be implemented in various ways, and the pixel arrangement method is not limited.

[0073] As illustrated in FIG. 11, the interposer substrate (210) may have a first pixel array position (P1), a second pixel array position (P2), and a third pixel array position (P3) set or marked according to the pixel array method. Alternatively, a mark for aligning the first to third color carrier substrates (110-1, 110-2, 110-3) may be formed on the edge of the interposer substrate (210).

[0074] The second transfer unit (200) can arrange the first color carrier substrate (110-1) and the interposer substrate (210) facing each other so that a plurality of first micro LEDs (12) face the interposer substrate (210). At this time, the second transfer unit (200) can align the first color carrier substrate (110-1) and the interposer substrate (210) using pixel array positions (P1, P2, P3) or marks of the interposer substrate (210) so that a plurality of first micro LEDs (12) are arranged corresponding to a first pixel array position (P1). The second transfer unit (200) can selectively and simultaneously irradiate a laser toward only the first micro LED (12) at a position corresponding to the first pixel array position (P1) among the plurality of first micro LEDs (12). The portion of the functional layer (413) of the first color carrier substrate (110-1) that is irradiated with a laser is cured and ablated, so that the first micro LEDs (12) can be transferred at once from the first color carrier substrate (110-1) to the first pixel array position (P1) of the interposer substrate (210).

[0075] The second transfer unit (200) can arrange the second color carrier substrate (110-2) and the interposer substrate (210) facing each other so that a plurality of second micro LEDs (22) face the interposer substrate (210). At this time, the second transfer unit (200) can align the second color carrier substrate (110-2) and the interposer substrate (210) using pixel array positions (P1, P2, P3) or marks of the interposer substrate (210) so that a plurality of second micro LEDs (22) are arranged corresponding to the second pixel array position (P2). The second transfer unit (200) can selectively and simultaneously irradiate a laser only toward the second micro LED (22) at the position corresponding to the second pixel array position (P2) among the plurality of second micro LEDs (22). The portion of the functional layer (413) of the second color carrier substrate (110-2) that is irradiated with a laser is cured and ablated, so that the second micro LEDs (22) can be transferred at once from the second color carrier substrate (110-2) to the second pixel array position (P2) of the interposer substrate (210).

[0076] The second transfer unit (200) can arrange the third color carrier substrate (110-3) and the interposer substrate (210) facing each other so that a plurality of third micro LEDs (32) face the interposer substrate (210). At this time, the second transfer unit (200) can align the third color carrier substrate (110-3) and the interposer substrate (210) using pixel array positions (P1, P2, P3) or marks of the interposer substrate (210) so that a plurality of third micro LEDs (32) are arranged corresponding to the third pixel array position (P3). The second transfer unit (200) can selectively and simultaneously irradiate a laser toward only the third micro LED (32) at the position corresponding to the third pixel array position (P3) among the plurality of third micro LEDs (32). The portion of the functional layer (413) of the third color carrier substrate (110-3) that is irradiated with a laser is cured and ablated, so that the third micro LEDs (32) can be transferred at once from the third color carrier substrate (110-3) to the third pixel array position (P3) of the interposer substrate (210).

[0077] The second transfer unit (200) can load an interposer substrate (210) on which a plurality of first micro LEDs (12), a plurality of second micro LEDs (22), and a plurality of third micro LEDs (32) are transferred according to a pixel arrangement method into a bonding unit (300).

[0078] A backplane (310) is loaded into the bonding section (300). The backplane (310) is a substrate on which a circuit for driving a micro LED display is formed. The bonding section (300) can perform the process of transferring a plurality of first micro LEDs (12), a plurality of second micro LEDs (22), and a plurality of third micro LEDs (32) from an interposer substrate (210) to the backplane (310).

[0079] As illustrated in FIG. 12, the bonding portion (300) may arrange the interposer substrate (210) and the backplane (310) facing each other so that a plurality of first micro LEDs (12), a plurality of second micro LEDs (22), and a plurality of third micro LEDs (32) face the backplane (310). At this time, a mark may be formed on the backplane (310) to position the plurality of first micro LEDs (12), a plurality of second micro LEDs (22), and a plurality of third micro LEDs (32) in correspondence with a predetermined position on the backplane (310), and the bonding portion (300) may align the interposer substrate (210) and the backplane (310) using the mark. The bonding unit (300) can transfer a plurality of first micro LEDs (12), a plurality of second micro LEDs (22), and a plurality of third micro LEDs (32) from the interposer substrate (210) to the backplane (310) at once by irradiating a laser or UV over the entire interposer substrate (210). Subsequently, the bonding unit (300) can bond a plurality of first micro LEDs (12), a plurality of second micro LEDs (22), and a plurality of third micro LEDs (32) to the backplane (310) using a high-temperature pressing method.

[0080] The drawings and detailed description of the invention referenced so far are merely exemplary of the invention and are used only for the purpose of explaining the invention, not to limit the meaning or the scope of the invention as defined in the claims. Therefore, those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of the invention should be determined by the technical spirit of the appended claims. Explanation of the symbols

[0081] 10: 1st color epi wafer 11, 21, 31: Wafer 12: 1st Micro LED 20: 2nd Color Epi Wafer 22: 2nd Micro LED 30: 3rd Color Epi Wafer 32: 3rd Micro LED 100: 1st Transfer Section 101 Transparent substrate 110: Carrier substrate 110': Preliminary carrier substrate 110-1: First color carrier substrate 110-2: Second color carrier substrate 110-3: Third color carrier substrate 200: 2nd Transfer Section 210: Interposer Substrate 300: Bonding section 310: Backplane 400: Carrier substrate providing unit 410: Transfer film 411: First release film 412: Pressure-sensitive adhesive layer 413: Functional layer 413-1: Substrate layer 413-2: High-elasticity adhesive layer 414: Second release film 1000: Micro LED transfer device

Claims

Claim 1 A transfer film for a micro LED laser transfer substrate comprises: a first release film; a point adhesive layer located on the first release film; a functional layer located on the point adhesive layer, comprising a buffer material that hardens and undergoes ablation upon absorbing a laser, or a dynamic release material that deforms and swells upon absorbing a laser; and a second release film located on the functional layer, wherein the first release film and the second release film support the point adhesive layer and the functional layer so that the point adhesive layer and the functional layer can be formed and maintained at a predetermined thickness, and the functional layer comprises a composite material of polyimide and neodymium-based butadiene rubber. Claim 2 delete Claim 3 A transfer film for a micro LED laser transfer substrate comprises: a first release film; a pressure-adhesive layer located on the first release film; a substrate layer located on the pressure-adhesive layer; a high-elasticity pressure-adhesive layer located on the substrate layer, comprising a buffer material that hardens and undergoes ablation upon absorbing a laser, or a dynamic release material that deforms and swells upon absorbing a laser; and a second release film located on the high-elasticity pressure-adhesive layer, wherein the first release film and the second release film support the pressure-adhesive layer and the high-elasticity pressure-adhesive layer so that the pressure-adhesive layer and the high-elasticity pressure-adhesive layer can be formed and maintained at a predetermined thickness, and the high-elasticity pressure-adhesive layer comprises a composite material of polyimide and neodymium-based butadiene rubber. Claim 4 In claim 3, the substrate layer supports the high-elasticity adhesive layer and improves the physical strength of the transfer film itself to reduce the degree of bending. Claim 5 A micro LED transfer device comprising: a first transfer unit for transferring a plurality of micro LEDs formed on an epi wafer to a carrier substrate; a second transfer unit for aligning the plurality of micro LEDs according to a pixel arrangement method and transferring them to an interposer substrate; a bonding unit for transferring a plurality of micro LEDs from the interposer substrate to a backplane; and a carrier substrate providing unit for providing the carrier substrate, on which a transfer film is laminated to a transparent substrate, to the first transfer unit, wherein the transfer film comprises: a first release film; a point adhesive layer located on the first release film; a functional layer located on the point adhesive layer and comprising a composite material of polyimide and neodymium-based butadiene rubber; and a second release film located on the functional layer, wherein the carrier substrate providing unit physically separates and removes the first release film from the point adhesive layer and performs lamination to attach the point adhesive layer to the upper surface of the transparent substrate to create a preliminary carrier substrate. Claim 6 In claim 5, the carrier substrate providing unit is a micro LED transfer device that produces the carrier substrate by physically separating and removing the second release film from the functional layer on the preliminary carrier substrate. Claim 7 A micro LED transfer device according to claim 5, wherein the second release film on the preliminary carrier substrate covers the functional layer to protect the functional layer from external contamination or physical shock. Claim 8 A micro LED transfer device according to claim 5, wherein the carrier substrate providing unit stores the spare carrier substrate in a separate storage space, takes the spare carrier substrate from the storage space upon the request of the first transfer unit, removes only the second release film, and provides the carrier substrate to the first transfer unit. Claim 9 In claim 5, the functional layer is a micro LED transfer device comprising a buffer material that hardens and undergoes ablation upon absorbing a laser, or a dynamic release material that deforms and swells upon absorbing a laser. Claim 10 A micro LED transfer device according to claim 5, wherein the functional layer comprises a substrate layer located on the adhesive layer; and a high-elasticity adhesive layer located on the substrate layer, and the high-elasticity adhesive layer is composed of a buffer material that hardens and undergoes ablation when absorbing a laser, or a dynamic release material that deforms and swells when absorbing a laser. Claim 11 A micro LED transfer method comprising: a step of fabricating a carrier substrate in which a transfer film is laminated onto a transparent substrate; a step of transferring a plurality of micro LEDs formed on an epi wafer onto the carrier substrate; a step of aligning the plurality of micro LEDs according to a pixel arrangement method and transferring them onto an interposer substrate; and a step of transferring a plurality of micro LEDs from the interposer substrate to a backplane, wherein the transfer film comprises: a first release film; a point adhesive layer located on the first release film; a functional layer located on the point adhesive layer and comprising a composite material of polyimide and neodymium-based butadiene rubber; and a second release film located on the functional layer, wherein the first release film is physically separated and removed from the point adhesive layer, and a lamination is performed to attach the point adhesive layer to the upper surface of the transparent substrate to create a preliminary carrier substrate, and the carrier substrate is fabricated by physically separating and removing the second release film from the functional layer on the preliminary carrier substrate. Claim 12 A micro LED transfer method according to claim 11, wherein the second release film on the preliminary carrier substrate covers the functional layer to protect the functional layer from external contamination or physical shock. Claim 13 A micro LED transfer method according to claim 11, wherein the preliminary carrier substrate is stored in a separate storage space, the preliminary carrier substrate is taken from the storage space, and only the second release film is removed to provide the carrier substrate. Claim 14 A micro LED transfer method according to claim 11, wherein the functional layer is a buffer material that hardens and undergoes ablation when it absorbs a laser, or a dynamic release material that deforms and swells when it absorbs a laser. Claim 15 A micro LED transfer method according to claim 11, wherein the functional layer comprises a substrate layer located on the adhesive layer; and a high-elasticity adhesive layer located on the substrate layer, wherein the high-elasticity adhesive layer is a buffer material that hardens and undergoes ablation when it absorbs a laser, or a dynamic release material that deforms and swells when it absorbs a laser.

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