Micro Light-Emitting Diode Master Transfer Method and System

Abstract

To provide a mass transfer method and system for micro light-emitting diodes.SOLUTION: The present disclosure discloses a mass transfer method and system for micro light emitting diodes, the mass transfer method includes the steps of: providing a component substrate on which a plurality of micro light emitting diodes are formed; picking up the micro light emitting diodes on the component substrate at least once by a plurality of bonding structures on a first transfer substrate, and transferring the micro light emitting diodes after every pick up to a second transfer substrate; and transferring each micro light emitting diode on the second transfer substrate into corresponding sub-pixels on a target substrate at one time, where one of the micro light emitting diodes on the second transfer substrate corresponds to one of the sub-pixels on the target substrate.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to the field of mass transfer technology, and more particularly to a method and system for mass transfer of micro light emitting diodes.

Background Art

[0002] A micro light emitting diode (Micro LED) is a device that miniaturizes and matrices a conventional LED structure for display. Since a micro light emitting diode (Micro LED) has advantages such as small size, high resolution, high brightness, high luminous efficiency, and low power consumption, it has become a research focus in the display field.

Summary of the Invention

[0003] The method for mass transfer of micro light emitting diodes according to an embodiment of the present disclosure includes: providing an element substrate on which a plurality of micro light emitting diodes are formed; using a plurality of adhesive structures on a first transfer substrate to pick up at least once the micro light emitting diodes on the element substrate and transfer them onto a second transfer substrate after each pick-up; collectively transferring each micro light emitting diode on the second transfer substrate into a corresponding sub-pixel of a target substrate, wherein one micro light emitting diode on the second transfer substrate corresponds to one sub-pixel of the target substrate.

[0004] In an embodiment of the present disclosure, one of the adhesive structures corresponds to one sub-pixel of the target substrate, forming a plurality of adhesive structures on the first transfer substrate includes: cutting a first transfer substrate mother board to obtain a first transfer substrate; Forming an adhesive material layer on the first transfer substrate; The method may further include patterning the adhesive material layer by a single patterning process to form a plurality of adhesive structures arranged in an array.

[0005] In an embodiment of the present disclosure, one of the adhesive structures corresponds to one sub-pixel of the target substrate. Forming a plurality of adhesive structures on the first transfer substrate may include: Forming an adhesive material layer on a first transfer substrate mother board; Patterning the adhesive material layer by a single patterning process to form a plurality of adhesive structures arranged in an array; and Cutting the first transfer substrate mother board on which the adhesive structures are formed to obtain a first transfer substrate on which a plurality of adhesive structures arranged in an array are formed.

[0006] In an embodiment of the present disclosure, the number of micro light-emitting diodes placed on the second transfer substrate may be greater than the number of micro light-emitting diodes placed on the first transfer substrate.

[0007] In an embodiment of the present disclosure, the micro light-emitting diodes include at least one type of micro light-emitting diodes of at least one color, the first transfer substrate is one, and The step of using the plurality of adhesive structures on the first transfer substrate to pick up the micro light-emitting diodes on the element substrate at least once and transfer them onto the second transfer substrate after each pick-up may include: For each color of micro light-emitting diodes, using the first transfer substrate to sequentially pick up the micro light-emitting diodes of the color on the element substrate multiple times, and transferring the micro light-emitting diodes of the color picked up each time to the micro light-emitting diode region corresponding to the color on the second transfer substrate.

[0008] In an embodiment of the present disclosure, the micro light-emitting diode includes at least one type of micro light-emitting diode, and one type of color corresponds to one of the first transfer substrates, Using a plurality of adhesive structures on the first transfer substrate to pick up the micro light-emitting diodes on the element substrate at least once and transfer them onto the second transfer substrate after each pick-up, the step For each color of micro light-emitting diode, using the first transfer substrate corresponding to the color, sequentially pick up the micro light-emitting diodes of the color on the element substrate a plurality of times, and transfer the micro light-emitting diodes of the color picked up each time to the micro light-emitting diode region corresponding to the color on the second transfer substrate, which may also be included.

[0009] In an embodiment of the present disclosure, picking up the micro light-emitting diodes of the color on the element substrate includes aligning the first transfer substrate and the element substrate, adhering the adhesive structures on the aligned first transfer substrate to the micro light-emitting diodes of the color to be picked up on the element substrate in a one-to-one correspondence, and separating the element substrate and the micro light-emitting diodes of the color to be picked up by a laser or a thermosetting process, so that the first transfer substrate picks up the adhered micro light-emitting diodes of the color, which may also be included.

[0010] In an embodiment of the present disclosure, the second transfer substrate includes an adhesive film layer covering the second transfer substrate, Transferring the micro light-emitting diodes of the color picked up each time to the micro light-emitting diode region corresponding to the color on the second transfer substrate includes aligning the first transfer substrate and the second transfer substrate, Adhering the color micro light-emitting diodes on the aligned first transfer substrate to the micro light-emitting diode regions corresponding to the color on the second transfer substrate in a one-to-one correspondence. It may include separating the first transfer substrate and the color micro light-emitting diodes on the first transfer substrate, and transferring the color micro light-emitting diodes to the micro light-emitting diode regions corresponding to the color on the second transfer substrate.

[0011] In an embodiment of the present disclosure, the material of the adhesive structure includes a thermal decomposition adhesive. Separating the first transfer substrate and the color micro light-emitting diodes on the first transfer substrate may include separating the first transfer substrate and the color micro light-emitting diodes on the first transfer substrate by a hot press process.

[0012] In an embodiment of the present disclosure, the material of the adhesive structure includes a photo decomposition adhesive. Separating the first transfer substrate and the color micro light-emitting diodes on the first transfer substrate may include separating the first transfer substrate and the color micro light-emitting diodes on the first transfer substrate by a laser.

[0013] In an embodiment of the present disclosure, the dimensions of the second transfer substrate are equal to or greater than the dimensions of the target substrate. The step of collectively transferring each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel of the target substrate includes aligning the second transfer substrate and the target substrate. Separating the second transfer substrate from the micro light-emitting diodes, and collectively transferring each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel of the target substrate may also be included.

[0014] In an embodiment of the present disclosure, the target substrate includes at least two target regions of the same dimension, and the dimension of one of the second transfer substrates is substantially the same as the dimension of one of the target regions. The step of collectively transferring each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel of the target substrate may include sequentially aligning the second transfer substrate and the target region, and each time alignment is performed, separating the second transfer substrate from the micro light-emitting diodes, and collectively transferring each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel of the target substrate.

[0015] In an embodiment of the present disclosure, the material of the adhesive film layer on the second transfer substrate includes a thermal decomposition adhesive. Separating the second transfer substrate from the micro light-emitting diodes may include separating the second transfer substrate and each micro light-emitting diode on the second transfer substrate by a hot press process.

[0016] In an embodiment of the present disclosure, the material of the adhesive film layer on the second transfer substrate includes a photo-decomposable adhesive. Separating the second transfer substrate from the micro light-emitting diodes may include separating the second transfer substrate and each micro light-emitting diode on the second transfer substrate by a laser.

[0017] In an embodiment of the present disclosure, the target substrate includes a plurality of sub-pixels including a first electrode and a second electrode formed in advance, and anisotropic conductive adhesives respectively located on sides of the first electrode and the second electrode spaced apart from the target substrate. When separating the second transfer substrate and each micro light-emitting diode on the second transfer substrate, or after separation, It may further include electrically connecting the electrodes of the micro light-emitting diodes separated from the second transfer substrate to the anisotropic conductive adhesives in the corresponding sub-pixels.

[0018] Embodiments of the present disclosure A first transfer substrate having a plurality of adhesive structures and configured to pick up at least once a micro light-emitting diode on the element substrate using the plurality of adhesive structures and transfer it onto the second transfer substrate after each pick-up, A second transfer substrate configured to collectively transfer each micro light-emitting diode on the second transfer substrate into a corresponding sub-pixel of the target substrate, One micro light-emitting diode on the second transfer substrate further provides a master transfer system for the micro light-emitting diodes corresponding to one sub-pixel of the target substrate.

[0019] In an embodiment of the present disclosure, the number of micro light-emitting diodes placed on the second transfer substrate may be greater than the number of micro light-emitting diodes placed on the first transfer substrate.

[0020] In an embodiment of the present disclosure, the dimensions of the second transfer substrate may be equal to or greater than the dimensions of the target substrate.

[0021] In an embodiment of the present disclosure, the target substrate includes at least two target regions of the same dimension, and the dimension of one second transfer substrate is approximately the same as the dimension of one target region.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0023] To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, not all of them. Furthermore, unless there is a contradiction, the embodiments of the present disclosure and the features of the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure described without creative efforts belong to the scope of the patent of the present disclosure.

[0024] Unless otherwise defined, technical terms or scientific terms used in the present disclosure should have the ordinary meanings understood by those skilled in the art of the present disclosure. The "first", "second" and similar terms used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Expressions such as "including" or "comprising" mean that the elements or articles described before this expression cover the elements or articles listed after this expression and their equivalents, but do not exclude other elements or articles. Terms such as "connected" or "coupled" are not limited to physical or mechanical connections, and include electrical connections whether direct or indirect.

[0025] Note that the dimensions and shapes of the figures in the drawings do not reflect the actual scale and are merely for illustrative purposes of the content of the present disclosure. Furthermore, throughout the text, the same or similar reference numerals indicate the same or similar components or components having the same or similar functions.

[0026] As a manufacturing procedure for micro light-emitting diodes, first, the light-emitting diode structure is thinned, miniaturized, and arrayed, and after the dimensions are made to be about 1 micron to 100 microns, the micro light-emitting diodes are transferred onto a circuit board in a batch manner and finally packaged. Here, the realization of batch transfer is a key difficult problem in this procedure. In view of this, the mass transfer technology has been developed. The mass transfer technology is a technology for transferring micro light-emitting diodes formed on an element substrate onto a circuit board in a batch manner such that each micro light-emitting diode corresponds to one sub-pixel on the circuit board. Since the dimensions of the micro light-emitting diodes are small and millions of sub-pixels are required on the circuit board, efficiently and selectively transferring the manufactured micro light-emitting diodes onto the circuit board in a batch manner at low cost is currently an urgent technical problem for those skilled in the art.

[0027] Based on the above, an embodiment of the present disclosure provides an example of a mass transfer method for micro light-emitting diodes that improves transfer efficiency.

[0028] An example of the mass transfer method for micro light-emitting diodes according to an embodiment of the present disclosure is shown in FIG. 1, and the mass transfer method may include steps S101 to S103. S101: Provide an element substrate on which a plurality of micro light-emitting diodes are formed. S102: Using a plurality of adhesive structures on a first transfer substrate, pick up the micro light-emitting diodes on the element substrate at least once and transfer them onto a second transfer substrate after each pick-up. S103. Transfer all the micro light-emitting diodes on the second transfer substrate into the corresponding sub-pixels on the target substrate at once. Here, one micro light-emitting diode on the second transfer substrate corresponds to one sub-pixel of the target substrate.

[0029] In the method for mass transfer of micro light-emitting diodes according to the embodiments of the present disclosure, a plurality of adhesive structures are provided on the first transfer substrate. The micro light-emitting diodes on the element substrate are picked up by these adhesive structures that are independent of each other. After being picked up, they are transferred onto the second transfer substrate. In this way, the micro light-emitting diodes on the element substrate can be selectively transferred onto the second transfer substrate, and the efficiency can be improved. Furthermore, the adhesive structure can be used repeatedly. Thereby, by picking up the micro light-emitting diodes at least once by the adhesive structure on the first transfer substrate, the adhesive structure is repeatedly used to transfer the micro light-emitting diodes on the element substrate onto the second transfer substrate, thereby reducing the number of the first transfer substrates used and achieving cost reduction. Also, by transferring all the micro light-emitting diodes on the second transfer substrate into the corresponding sub-pixels on the target substrate at once, multiple additional transfers are not required, and the efficiency can be improved.

[0030] Generally, the target substrate is used for forming a display panel and imparts a display function to the display panel. In a specific implementation, as shown in FIGS. 2a and 2b, the target substrate 100 includes a plurality of pixel units PX arranged in an array, and each pixel unit may include a plurality of sub-pixels. Further, the sub-pixels in the target substrate 100 are arranged in an array. As an example, as shown in FIGS. 2a and 2b, the pixel unit PX may include a red sub-pixel SPX-R, a green sub-pixel SPX-G, and a blue sub-pixel SPX-B. In this way, when the target substrate 100 is applied to a display panel, it enables color display through the mixing of red, green, and red. Alternatively, the pixel unit may include a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel. In this way, when the target substrate is applied to a display panel, it enables color display through the mixing of red, green, red, and white. Of course, in actual application, the colors of the sub-pixels in the pixel unit can be designed and determined according to the actual application environment and are not limited here.

[0031] Generally, a driving circuit is formed on a base substrate by a thin film transistor (TFT) manufacturing process to form a circuit board. In this way, after the micro light-emitting diodes are transferred into the sub-pixels of the circuit board, the micro light-emitting diodes can be driven to emit light by the driving circuit. In a specific implementation, in the embodiments of the present disclosure, the target substrate may be a circuit board. As shown in FIG. 2b, each sub-pixel may include a pre-formed driving circuit 150, and a first electrode 110 and a second electrode 120 that are electrically connected to the driving circuit 150 respectively. The positive electrode of the micro light-emitting diode may be electrically connected to the first electrode 110, and the negative electrode of the micro light-emitting diode may be electrically connected to the second electrode 120. Thereby, the driving circuit 150 inputs a voltage or current to the micro light-emitting diode electrically connected via the first electrode 110 and the second electrode 120 to drive the micro light-emitting diode to emit light.

[0032] As an example, the base substrate may include a glass substrate. Of course, when actually applied, the base substrate may be a substrate of other types of materials, and in this regard, it can be designed and determined according to the actual application environment, and is not limited here.

[0033] In specific implementation, in the embodiments of the present disclosure, a plurality of micro light-emitting diodes formed on the element substrate are arranged in an array, and furthermore, one micro light-emitting diode in the element substrate may correspond to one sub-pixel of the target substrate. As an example, as shown in FIGS. 3d to 3f, each micro light-emitting diode has a positive electrode 221, a negative electrode 222, and a light-emitting chip body 223. As an example, the size of the element substrate may be smaller than the size of the target substrate. Furthermore, micro light-emitting diodes of the same color may be formed on the element substrate. As shown in FIGS. 3a and 3d, on the element substrate 200-R, a plurality of red micro light-emitting diodes W-R arranged in an array may be formed such that the red micro light-emitting diodes W-R on the element substrate 200-R correspond one-to-one to the red sub-pixels SPX-R in a certain area of the target substrate 100. As shown in FIGS. 3b and 3e, on the element substrate 200-G, a plurality of green micro light-emitting diodes W-G arranged in an array may be formed such that the green micro light-emitting diodes W-G on the element substrate 200-G correspond one-to-one to the green sub-pixels SPX-G in a certain area of the target substrate 100. As shown in FIGS. 3c and 3f, on the element substrate 200-B, a plurality of blue micro light-emitting diodes W-B arranged in an array may be formed such that the blue micro light-emitting diodes W-B on the element substrate 200-B correspond one-to-one to the blue sub-pixels SPX-B in a certain area of the target substrate 100. Or, on the element substrate, a plurality of micro light-emitting diodes of different colors arranged in an array may be formed, and it is not limited here.

[0034] Furthermore, in specific implementations, in the embodiments of the present disclosure, the element substrate may be one of a wafer, a heat collecting material film, and a sapphire substrate. As an example, as shown in FIGS. 3a to 3c, the shape of the wafer is generally circular, and each micro light emitting diode is arranged in an array on the wafer. Of course, in actual application, the element substrate may be a substrate of other types of materials, which can be designed and determined according to the actual application environment and is not limited herein.

[0035] In specific implementations, as shown in FIGS. 3a to 4, the shape of the first transfer substrate 300 may be rectangular, for example, rectangular or square. Furthermore, the dimensions of the first transfer substrate 300 may be smaller than the dimensions of the element substrate 200, for example, 6 inches, 8 inches, or 12 inches. Also, the dimensions of the first transfer substrate 300 may be larger than the dimensions of the element substrate 200. In the embodiments of the present disclosure, as shown in FIG. 4, a plurality of adhesive structures 310 arranged in an array may be formed on the first transfer substrate 300. Furthermore, one adhesive structure 310 corresponds to one sub-pixel of the target substrate 100. As an example, forming a plurality of adhesive structures on the first transfer substrate may include the step of cutting the first transfer substrate mother board to obtain the first transfer substrate, and the step of forming an adhesive material layer on the first transfer substrate, and the step of patterning the adhesive material layer by one patterning process to form a plurality of adhesive structures arranged in an array. In this way, each patterned adhesive structure 310 is formed by one patterning process, thereby simplifying the manufacturing process, reducing production costs, and improving production efficiency.

[0036] Also, first, the first transfer substrate mother board may be patterned and then cut to form the first transfer substrate. In such a case, the thickness and spacing of the adhesive structures on each first transfer substrate will be more uniform. In specific implementations, forming a plurality of adhesive structures on the first transfer substrate may include Forming an adhesive material layer on a first transfer substrate mother board; Patterning the adhesive material layer by a single patterning process to form a plurality of adhesive structures arranged in an array; It may include cutting the first transfer substrate mother board on which the adhesive structure is formed to obtain a first transfer substrate on which a plurality of adhesive structures arranged in an array are formed. In such a case, each patterned adhesive structure 310 is formed by a single patterning process, thereby simplifying the manufacturing process, reducing production costs, and improving production efficiency.

[0037] As an example, in a specific implementation, in an embodiment of the present disclosure, the patterning process may include a lithography process and an etching step. Here, the lithography process refers to a process of forming a pattern using a photoresist, a mask, an exposure machine, etc., including process steps such as exposure and development. In a specific implementation, according to the structure formed in the present disclosure, a corresponding patterning process can be selected. Of course, the adhesive structure may be formed by other processes such as a printing process and is not limited here.

[0038] In a specific implementation, as shown in FIG. 4, the dimension of the adhesive structure 310 may be equal to or less than the dimension of a single micro light-emitting diode. As an example, the dimension of the adhesive structure 310 is equal to the dimension of a single micro light-emitting diode. For example, the orthographic projection of the adhesive structure 310 on the first transfer substrate 300 overlaps with the orthographic projection of the micro light-emitting diode on the first transfer substrate 300.

[0039] Alternatively, for a specific implementation, the dimensions of the adhesive structure 310 may be larger than those of a single micro-light emitting diode. Further, as shown in FIGS. 4 and 3a, in at least one of the first direction F1 and the second direction F2, the width of the adhesive structure 310 may be smaller than the sum of the width of the micro-light emitting diode and the gap between elements. As an example, in the first direction F1, the width C1 of the adhesive structure 310 is smaller than the sum of the width D01 of the micro-light emitting diode and the gap D1 between two adjacent micro-light emitting diodes, that is, C1 < D01 + D1. In the second direction F2, the width C2 of the adhesive structure 310 is smaller than the sum of the width D02 of the micro-light emitting diode and the gap D2 between two adjacent micro-light emitting diodes, that is, C2 < D02 + D2.

[0040] For a specific implementation, as shown in FIG. 4, the shape of the adhesive structure 310 may include shapes such as a rectangle or a square. Of course, when actually applied, the shape of the adhesive structure 310 may be other shapes and is not limited here.

[0041] For a specific implementation, as shown in FIG. 5, the second transfer substrate 400 may further include an adhesive film layer 410 covering the second transfer substrate. The adhesive film layer 410 has micro-light emitting diode regions corresponding to different colors. Further, one micro-light emitting diode region corresponds to one sub-pixel of the target substrate 100. As an example, the adhesive film layer 410 has a micro-light emitting diode region S-R corresponding to red, a micro-light emitting diode region S-G corresponding to green, and a micro-light emitting diode region S-B corresponding to blue. Here, the micro-light emitting diode region S-R corresponds to the red sub-pixel SPX-R of the target substrate 100, the micro-light emitting diode region S-G corresponds to the red sub-pixel SPX-G of the target substrate 100, and the micro-light emitting diode region S-B corresponds to the red sub-pixel SPX-B of the target substrate 100.

[0042] In a specific implementation, in an embodiment of the present disclosure, the number of micro light-emitting diodes placed on the second transfer substrate may be more than the number of micro light-emitting diodes placed on the first transfer substrate. Thereby, the number of transfers from the second transfer substrate to the target substrate can be reduced, and the efficiency can be further improved. As an example, as shown in FIGS. 4 and 5, in order to make the number of micro light-emitting diodes that can be placed on the second transfer substrate more than the number of micro light-emitting diodes placed on the first transfer substrate, the size of the second transfer substrate is larger than the size of the first transfer substrate. Of course, when actually applied, the size of the second transfer substrate may be an integer multiple of the size of the first transfer substrate, such as 1 times, 2 times, etc., and this can be designed and determined according to the actual application environment, and is not limited here.

[0043] As an example, the first transfer substrate may include a glass substrate. Of course, when actually applied, the first transfer substrate may use substrates of other types of materials, and is not limited here.

[0044] As an example, the second transfer substrate may include a glass substrate and a heat collecting material film. Of course, when actually applied, the second transfer substrate may use substrates of other types of materials, and is not limited here.

[0045] In a specific implementation, there may be a plurality of element substrates. For example, there is at least one ￥ element substrate 200-R on which a red light-emitting diode W-R is formed, at least one element substrate 200-G on which a green light-emitting diode W-G is formed, and at least one element substrate 200-B on which a blue light-emitting diode W-B is formed. In this way, the micro light-emitting diodes on the target substrate can include a plurality of micro light-emitting diodes of different colors. Of course, when actually applied, the number of the element substrate 200-R, the element substrate 200-G, and the element substrate 200-B used can be designed and determined according to the actual application environment, and is not limited here.

[0046] In a specific implementation, in an embodiment of the present disclosure, one first transfer substrate may be provided. In such a case, using a plurality of adhesive structures on the first transfer substrate to pick up at least one micro light-emitting diode on the element substrate at least once, and the step of transferring to the second transfer substrate after each pick-up may include, for each color of micro light-emitting diode, using the first transfer substrate to pick up the micro light-emitting diodes of that color on the element substrate multiple times, and transferring each picked-up micro light-emitting diode of that color to the micro light-emitting diode region corresponding to that color on the second transfer substrate. As an example, for the red micro light-emitting diode W-R, using the adhesive structure 310 on the first transfer substrate 300 to pick up the red micro light-emitting diode W-R on the element substrate 200-R multiple times, and transferring each picked-up red micro light-emitting diode W-R to the micro light-emitting diode region S-R corresponding to red on the second transfer substrate 400, so that all of the micro light-emitting diode region S-R corresponding to red on the second transfer substrate 400 is provided with red micro light-emitting diodes W-R.

[0047] In a specific implementation, in an embodiment of the present disclosure, picking up the micro light-emitting diodes of that color on the element substrate includes aligning the first transfer substrate and the element substrate, adhering the adhesive structure on the aligned first transfer substrate to the micro light-emitting diodes of that color to be picked up on the element substrate in a one-to-one correspondence, separating the element substrate and the micro light-emitting diodes of that color to be picked up by a laser so that the first transfer substrate picks up the adhered micro light-emitting diodes of that color, or separating the element substrate and the micro light-emitting diodes of that color to be picked up by a thermosetting process so that the first transfer substrate picks up the adhered micro light-emitting diodes of that color.

[0048] For specific implementation, in the embodiments of the present disclosure, transferring the micro light-emitting diodes of the color picked up each time to the micro light-emitting diode region corresponding to the color on the second transfer substrate may include: aligning the first transfer substrate and the second transfer substrate; adhering the micro light-emitting diodes of the color on the aligned first transfer substrate to the micro light-emitting diode region corresponding to the color on the second transfer substrate in a one-to-one correspondence; separating the first transfer substrate and the micro light-emitting diodes of the color on the first transfer substrate, thereby transferring the micro light-emitting diodes of the color to the micro light-emitting diode region corresponding to the color on the second transfer substrate.

[0049] For specific implementation, the material of the adhesive structure may include a thermally decomposable adhesive. In the embodiments of the present disclosure, separating the first transfer substrate and the micro light-emitting diodes of the color on the first transfer substrate may include separating the first transfer substrate and the micro light-emitting diodes of the color on the first transfer substrate by a hot press process. In this way, by the hot press process, the thermally decomposable adhesive is heated to lose its adhesiveness, thereby enabling the separation of the first transfer substrate and the micro light-emitting diodes of the color on the first transfer substrate. On the other hand, the micro light-emitting diodes of the color separated from the first transfer substrate are fixed to the micro light-emitting diode region corresponding to the color on the second transfer substrate under the action of pressure.

[0050] For specific implementations, the material of the adhesive structure may include a photo-decomposable adhesive. In an embodiment of the present disclosure, separating the first transfer substrate and the micro light-emitting diode of the color on the first transfer substrate may include separating the first transfer substrate and the micro light-emitting diode of the color on the first transfer substrate by a laser. In this way, by irradiating the first transfer substrate with a laser, the photo-decomposable adhesive is exposed to light irradiation and loses its adhesiveness, thereby enabling the separation of the first transfer substrate and the micro light-emitting diode of the color picked up.

[0051] For specific implementations, the size of the second transfer substrate may be equal to or larger than the size of the target substrate. As an example, the size of the second transfer substrate 400 is larger than the size of the target substrate 100. Alternatively, as shown in FIGS. 2a and 5, the size of the second transfer substrate 400 may be substantially equal to the size of the target substrate 100. In the actual process, due to limitations by process conditions and influences by other factors, there may be some deviation. Therefore, in the embodiments of the present disclosure, "equal" and "the same" mean "equal" and "the same" that conform to the range allowed by the error, or it is sufficient to substantially meet the above conditions, and in either case, it belongs to the patent scope of the present disclosure.

[0052] For specific implementations, in an embodiment of the present disclosure, the step of collectively transferring each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel of the target substrate includes aligning the second transfer substrate and the target substrate, and separating the second transfer substrate and the micro light-emitting diodes on the second transfer substrate, and then collectively transferring each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel of the target substrate.

[0053] For specific implementation, the material of the adhesive film layer on the second transfer substrate may include a photo-decomposable adhesive. In an embodiment of the present disclosure, separating the second transfer substrate from the micro light-emitting diodes may include separating the second transfer substrate from each micro light-emitting diode on the second transfer substrate by a laser. Thus, by irradiating with a laser, the photo-decomposable adhesive loses its adhesiveness, thereby separating the second transfer substrate from the picked-up micro light-emitting diodes and enabling each micro light-emitting diode on the second transfer substrate to be transferred en masse into the corresponding sub-pixel of the target substrate.

[0054] For specific implementation, the material of the adhesive film layer on the second transfer substrate may include a thermo-decomposable adhesive. In an embodiment of the present disclosure, separating the second transfer substrate from the micro light-emitting diodes may include separating the second transfer substrate from each micro light-emitting diode on the second transfer substrate by a hot press process. Thus, by the hot press process, while separating the second transfer substrate from the picked-up micro light-emitting diodes, the adhesion between the micro light-emitting diodes and the target substrate is made stronger.

[0055] For specific implementation, as shown in FIG. 2b, the target substrate may further include an anisotropic conductive adhesive 130 respectively located on the side of the target substrate 100 spaced apart from the first electrode 110 and the second electrode 120. In an embodiment of the present disclosure, when separating the second transfer substrate from each micro light-emitting diode on the second transfer substrate, or after separation, it may further include electrically connecting the electrodes of the micro light-emitting diodes separated from the second transfer substrate to the anisotropic conductive adhesive in the corresponding sub-pixel. As an example, by a thermosetting process, the electrodes of the micro light-emitting diodes separated from the second transfer substrate are electrically connected to the anisotropic conductive adhesive in the corresponding sub-pixel. Since the anisotropic conductive adhesive 130 may be substantially the same as in the related art, it will not be described in detail here.

[0056] In a specific implementation, the anisotropic conductive adhesive may include an adhesive material and a metal material uniformly dispersed in the adhesive material. Here, the metal material may include Sn balls, Au, etc. As an example, as shown in FIG. 2b, forming the anisotropic conductive adhesive 130 on the first electrode 110 and the second electrode 120 of the target substrate includes first uniformly dispersing Sn balls in the adhesive material, and then applying the adhesive material in which the Sn balls are dispersed on the first electrode 110 and the second electrode 120 of the target substrate to form a layer of conductive adhesive layer, and patterning this conductive adhesive layer by a patterning process to form the anisotropic conductive adhesives 130 respectively located on the sides of the first electrode 110 and the second electrode 120 away from the target substrate 100. Here, the patterning process may include a lithography process and an etching process.

[0057] Note that the anisotropic conductive adhesive has both adhesiveness and conductivity, and its adhesiveness may decrease if left for a long time. Therefore, when the number of micro-light-emitting diodes placed on the second transfer substrate is less than or equal to the number of micro-light-emitting diodes placed on the first transfer substrate, the number of times of transferring the micro-light-emitting diodes to the target substrate increases, and the time taken for the transfer becomes longer. That is, it becomes difficult for all of the micro-light-emitting diodes to be transferred onto the target substrate within a short time, and the performance of the anisotropic conductive adhesive deteriorates. In the embodiments of the present disclosure, the number of micro-light-emitting diodes placed on the second transfer substrate is more than the number of micro-light-emitting diodes placed on the first transfer substrate, the size of the second transfer substrate is equal to or larger than the size of the target substrate, and one micro-light-emitting diode region on the second transfer substrate corresponds to one sub-pixel on the target substrate. Thus, the micro-light-emitting diodes on the second transfer substrate can be transferred to the target substrate in only one transfer. In this way, the transfer time is reduced, the performance stability of the anisotropic conductive adhesive is ensured, and the stability of the target substrate when applied to the display panel is improved.

[0058] Hereinafter, the process of the master transfer method will be exemplified in the embodiments, but it is obvious that the specific process is not limited thereto.

[0059] The master transfer method according to the embodiments of the present disclosure may include the following steps (1) to (9).

[0060] Step (1) As shown in FIGS. 6a and 6b, an adhesive material layer is formed on the first transfer substrate mother board 30 using a thermal decomposition adhesive. Next, the adhesive material layer is sequentially patterned by a lithography process and an etching process to form a plurality of adhesive structures 310 arranged in an array. FIG. 6a is a top surface structure schematic diagram, and FIG. 6b is a cross-sectional structure schematic diagram along the AA' direction of FIG. 6a.

[0061] Step (2) As shown in FIGS. 4 and 6c, the first transfer substrate mother board 30 is cut along the cutting line 31 to obtain a first transfer substrate 300 on which a plurality of adhesive structures 310 arranged in an array are formed. FIG. 6c is a cross-sectional structure schematic diagram along the AA' direction of FIG. 4.

[0062] Step (3) As shown in FIGS. 3a to 3f, a wafer 200-R on which a plurality of red micro light-emitting diodes W-R arranged in an array are formed, a wafer 200-G on which a plurality of green micro light-emitting diodes W-G arranged in an array are formed, and a wafer 200-B on which a plurality of blue micro light-emitting diodes W-B arranged in an array are formed are provided.

[0063] Step (4) Align the first transfer substrate 300 with the wafer 200-R. As shown in FIGS. 4, 3a, 6d, and 6e, the shape of the first transfer substrate 300 may be rectangular, for example, rectangular or square. In this way, first transfer alignment marks 320 may be provided at the four corners of the first transfer substrate 300. Further, element alignment marks 210 are also formed on the wafer 200-R. In this manner, the first transfer alignment marks 320 and the element alignment marks 210 are controlled to be aligned so that the adhesive structure 310 on the first transfer substrate 300 is aligned one-to-one with the red micro light-emitting diode W-R to be picked up on the wafer 200-R. Next, the adhesive structure 310 on the aligned first transfer substrate 300 is adhesively bonded one-to-one with the red micro light-emitting diode W-R to be picked up on the wafer 200-R, thereby adhesively bonding the red micro light-emitting diode W-R to be picked up to the adhesive structure 310. FIG. 6d is a top surface structure schematic diagram, and FIG. 6e is a cross-sectional structure schematic diagram taken along the AA' direction of FIG. 6d.

[0064] Step (5) By means of a heat curing process, the wafer 200-R and the red micro light-emitting diode W-R to be picked up are separated, while the adhesion between the adhesive structure 310 and the red micro light-emitting diode W-R to be picked up is made stronger. Thereby, as shown in FIGS. 6f and 6g, the first transfer substrate 300 picks up the adhered red micro light-emitting diode W-R. In FIG. 6f, the dotted line portion of the wafer 200-R represents the red micro light-emitting diode W-R picked up by the first transfer substrate 300. FIG. 6f is a top surface structure schematic diagram, and FIG. 6g is a cross-sectional structure schematic diagram taken along the AA' direction of FIG. 6f.

[0065] Step (6) Align the first transfer substrate 300 and the second transfer substrate 400. As shown in FIGS. 4, 5, 6f to 6i, the shape of the second transfer substrate 400 may be, for example, rectangular and the same as the dimensions of the target substrate. In this way, second transfer alignment marks 420 may be provided at the four corners of the second transfer substrate 400. In this manner, control the first transfer alignment mark 320 and the second transfer alignment mark 420 to be aligned so that the red micro light-emitting diodes W-R adhered to the first transfer substrate 300 are aligned one-to-one with the adhesive film layer in the micro light-emitting diode region S-R corresponding to red in the second transfer substrate 400. Next, adhere the red micro light-emitting diodes W-R adhered to the aligned first transfer substrate 300 one-to-one with the adhesive film layer in the micro light-emitting diode region S-R corresponding to red in the second transfer substrate 400, thereby adhering the red micro light-emitting diodes W-R to the adhesive film layer 410. FIG. 6h is a top surface structure schematic diagram, and FIG. 6i is a cross-sectional structure schematic diagram along the AA' direction of FIG. h.

[0066] Step (7) By means of a hot press process, separate the first transfer substrate 300 and the red micro light-emitting diodes W-R on the first transfer substrate 300, while strengthening the adhesion between the adhesive film layer 420 and the red micro light-emitting diodes W-R. Thereby, the second transfer substrate 400 picks up the adhered red micro light-emitting diodes W-R. As shown in FIGS. 6j and 6k, the red micro light-emitting diodes W-R picked up by the first transfer substrate 300 for the first time are transferred to the micro light-emitting diode region S-R corresponding to red in the second transfer substrate 400. FIG. 6j is a top surface structure schematic diagram, and FIG. 6k is a cross-sectional structure schematic diagram along the AA' direction of FIG. 6j.

[0067] Next, as shown in FIGS. 6l and 6m, the processes of the above steps (4) to (7) are repeated, and red micro light-emitting diodes W-R are respectively adhered to the red-corresponding micro light-emitting diode region S-R of the second transfer substrate 400. FIG. 6l is a top surface structure schematic diagram, and FIG. 6m is a cross-sectional structure schematic diagram along the AA' direction of FIG. 6l.

[0068] Next, as shown in FIGS. 6l and 6m, the processes of the above steps (4) to (7) are repeated, and the adhesive structure 310 on the first transfer substrate 300 is used to pick up the green micro light-emitting diodes W-G on the wafer 200-G multiple times. Each time the picked-up green micro light-emitting diode W-G is transferred to the micro light-emitting diode region S-G corresponding to green of the second transfer substrate 400, so that green micro light-emitting diodes W-G are provided in all of the micro light-emitting diode regions S-G corresponding to green of the second transfer substrate 400.

[0069] Next, as shown in FIGS. 6l and 6m, the processes of the above steps (4) to (7) are repeated, and the adhesive structure 310 on the first transfer substrate 300 is used to pick up the blue micro light-emitting diodes W-B on the wafer 200-B multiple times. Each time the picked-up blue micro light-emitting diode W-B is transferred to the micro light-emitting diode region S-B corresponding to blue of the second transfer substrate 400, so that blue micro light-emitting diodes W-B are provided in all of the micro light-emitting diode regions S-B corresponding to blue of the second transfer substrate 400.

[0070] Step (8) Align the second transfer substrate 400 and the target substrate 100. As shown in FIGS. 2a, 2b, 6l to 6o, target alignment marks 140 are provided at the four corners of the target substrate 100. In this way, control the second transfer alignment mark 420 and the target alignment mark 140 to be aligned, so that each red micro light-emitting diode W-R adhered to the second transfer substrate 400 is aligned one-to-one with the red sub-pixel SPX-R on the target substrate 100 respectively, and each green micro light-emitting diode W-G adhered to the second transfer substrate 400 is aligned one-to-one with the green sub-pixel SPX-G on the target substrate 100 respectively, and each blue micro light-emitting diode W-B adhered to the second transfer substrate 400 is aligned one-to-one with the blue sub-pixel SPX-B on the target substrate 100 respectively. FIG. 6n is a schematic top surface structure diagram, and FIG. 6o is a schematic cross-sectional structure diagram along the AA' direction of FIG. 6n.

[0071] Step (9) As shown in FIGS. 6n and 6o, irradiate the second transfer substrate with a laser to cause the adhesive film layer 410 formed of a photo-decomposable adhesive to lose its adhesiveness, and separate the second transfer substrate and each micro light-emitting diode on the second transfer substrate. Next, through a heat-curing process, transfer each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel on the target substrate in a batch, and then, under the action of pressure, electrically connect the electrodes of each micro light-emitting diode to the anisotropic conductive adhesive in the corresponding sub-pixel. Here, the positive electrode 221 of each micro light-emitting diode can be electrically connected to the first electrode 110 through the anisotropic conductive adhesive 130, and the negative electrode 222 of each micro light-emitting diode can be electrically connected to the second electrode 120 through the anisotropic conductive adhesive 130.

[0072] In another method for mass-transferring micro light-emitting diodes according to an embodiment of the present disclosure, modifications are made to the embodiments of the above embodiments. Hereinafter, only the differences between this embodiment and the above embodiments will be described, and the similarities therebetween will not be described in detail here.

[0073] Step (1) As shown in FIGS. 6a and 6b, an adhesive material layer is formed on the first transfer substrate mother board 30 using a photo-decomposable adhesive. Next, the adhesive material layer is sequentially patterned by a lithography process and an etching process to form a plurality of adhesive structures 310 arranged in an array.

[0074] Steps (2) to (6) may be substantially the same as steps (2) to (6) of the above embodiment and will not be described in detail here.

[0075] Step (7) The first transfer substrate 300 and the red micro light-emitting diode W-R on the first transfer substrate 300 are separated by laser irradiation. Next, the adhesion between the adhesive film layer 420 and the red micro light-emitting diode W-R is strengthened by a heat curing process. Thereby, the second transfer substrate 400 picks up the adhered red micro light-emitting diode W-R. As shown in FIGS. 6j and 6k, the red micro light-emitting diode W-R picked up by the first transfer substrate 300 for the first time is transferred to the micro light-emitting diode region S-R corresponding to red in the second transfer substrate 400.

[0076] Next, as shown in FIGS. 6l and 6n, the processes of steps (4) to (7) are repeated to adhere red micro light-emitting diodes W-R to the micro light-emitting diode region S-R corresponding to red in the second transfer substrate 400, respectively.

[0077] Next, as shown in FIGS. 6l and 6n, the processes of steps (4) to (7) above are repeated. Using the adhesive structure 310 on the first transfer substrate 300, the green micro light-emitting diodes W-G on the wafer 200-G are picked up multiple times, and each time the picked-up green micro light-emitting diodes W-G are transferred to the micro light-emitting diode region S-G corresponding to green in the second transfer substrate 400, whereby all of the micro light-emitting diode regions S-G corresponding to green in the second transfer substrate 400 are provided with green micro light-emitting diodes W-G.

[0078] Next, as shown in FIGS. 6l and 6n, the processes of steps (4) to (7) above are repeated. Using the adhesive structure 310 on the first transfer substrate 300, the blue micro light-emitting diodes W-B on the wafer 200-B are picked up multiple times, and each time the picked-up blue micro light-emitting diodes W-B are transferred to the micro light-emitting diode region S-B corresponding to blue in the second transfer substrate 400, whereby all of the micro light-emitting diode regions S-B corresponding to blue in the second transfer substrate 400 are provided with blue micro light-emitting diodes W-B.

[0079] Step (8) Align the second transfer substrate 400 with the target substrate 100. As shown in FIGS. 2a, 2b, 6l to 6o, target alignment marks 140 are provided at the four corners of the target substrate 100. In this way, control the second transfer alignment mark 420 and the target alignment mark 140 to be aligned, so that each red micro light-emitting diode W-R adhered to the second transfer substrate 400 is aligned one-to-one with the red sub-pixel SPX-R on the target substrate 100 respectively, and each green micro light-emitting diode W-G adhered to the second transfer substrate 400 is aligned one-to-one with the green sub-pixel SPX-G on the target substrate 100 respectively, and each blue micro light-emitting diode W-B adhered to the second transfer substrate 400 is aligned one-to-one with the blue sub-pixel SPX-B on the target substrate 100 respectively.

[0080] Step (9) As shown in FIGS. 6n and 6o, by means of a hot press process, make the adhesive film layer 410 formed of a thermally decomposable adhesive lose its adhesiveness, and separate the second transfer substrate and each micro light-emitting diode on the second transfer substrate. On the other hand, due to the action of pressure, electrically connect the electrodes of each micro light-emitting diode to the anisotropic conductive adhesive in the corresponding sub-pixel, and transfer each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel of the target substrate all at once.

[0081] In another method for mass-transferring micro light-emitting diodes according to an embodiment of the present disclosure, modifications are made to the embodiments described above. Only the differences between this embodiment and the above embodiments will be described, and the similarities therebetween will not be described in detail here.

[0082] For specific implementation, in the embodiments of the present disclosure, one type of color micro light-emitting diode may correspond to one first transfer substrate. As an example, the red micro light-emitting diode corresponds to the first first transfer substrate 300-R, the green micro light-emitting diode corresponds to the second first transfer substrate 300-G, and the blue micro light-emitting diode corresponds to the third first transfer substrate 300-B.

[0083] For specific implementation, in the embodiments of the present disclosure, the step of using a plurality of adhesive structures on the first transfer substrate to pick up the micro light-emitting diodes on the element substrate at least once and transfer them onto the second transfer substrate after each pick-up includes, for each color of micro light-emitting diode, using the corresponding color first transfer substrate to pick up the micro light-emitting diodes of the corresponding color on the element substrate multiple times, and transferring the micro light-emitting diodes of the color picked up each time to the micro light-emitting diode region of the corresponding color in the second transfer substrate. As an example, for the red micro light-emitting diode W-R, the adhesive structure 310 on the first first transfer substrate 300 corresponding to red is used to pick up the red micro light-emitting diode W-R on the element substrate 200-R multiple times, and the red micro light-emitting diode W-R picked up each time is transferred to the micro light-emitting diode region S-R corresponding to red in the second transfer substrate 400, so that all of the micro light-emitting diode region S-R corresponding to red in the second transfer substrate 400 is provided with the red micro light-emitting diode W-R.

[0084] Hereinafter, the process of the mass transfer method in the embodiment is exemplified, but it is obvious that the specific process is not limited thereto.

[0085] The mass transfer method according to the embodiments of the present disclosure may include the following steps (4) to (11) in addition to including the steps (1) to (3) and steps (8) to (9) of the above embodiments.

[0086] Step (4): Align the first transfer substrate 300-R corresponding to red with the wafer 200-R. As shown in FIGS. 4, 3a, and 7a, the shape of the first transfer substrate 300-R may be rectangular, for example, rectangular or square. In this way, first transfer alignment marks 320 may be provided at the four corners of the first transfer substrate 300-R. Further, element alignment marks 210 are also formed on the wafer 200-R. In this manner, by controlling the first transfer alignment marks 320 and the element alignment marks 210 to be aligned, the adhesive structure 310 on the first transfer substrate 300-R is aligned one-to-one with the red micro light-emitting diode W-R to be picked up on the wafer 200-R. Next, the adhesive structure 310 on the aligned first transfer substrate 300-R and the red micro light-emitting diode W-R to be picked up on the wafer 200-R are adhesively bonded one-to-one, whereby the red micro light-emitting diode W-R to be picked up is adhesively bonded to the adhesive structure 310.

[0087] Step (5): By means of a thermosetting process, while separating the wafer 200-R from the red micro light-emitting diode W-R to be picked up, the adhesion between the adhesive structure 310 and the red micro light-emitting diode W-R to be picked up is made stronger. Thereby, as shown in FIG. 7b, the first transfer substrate 300-R picks up the adhered red micro light-emitting diode W-R. In FIG. 7b, the dotted line portion of the wafer 200-R represents the red micro light-emitting diode W-R picked up by the first transfer substrate 300-R.

[0088] Step (6) Align the first transfer substrate 300-R and the second transfer substrate 400. As shown in FIGS. 4, 5, 7b, and 7c, the shape of the second transfer substrate 400 may be, for example, rectangular and the same as the dimensions of the target substrate. In this way, second transfer alignment marks 420 may be provided at the four corners of the second transfer substrate 400. In this way, control the first transfer alignment mark 320 and the second transfer alignment mark 420 to be aligned, so that the red micro light-emitting diodes W-R adhered to the first transfer substrate 300-R are one-to-one corresponding to and aligned with the adhesive film layer in the micro light-emitting diode region S-R corresponding to red on the second transfer substrate 400. Next, adhere the red micro light-emitting diodes W-R adhered to the aligned first transfer substrate 300-R one-to-one corresponding to the adhesive film layer in the micro light-emitting diode region S-R corresponding to red on the second transfer substrate 400, whereby the red micro light-emitting diodes W-R are adhered to the adhesive film layer 410.

[0089] Step (7) By means of a hot press process, separate the first transfer substrate 300-R and the red micro light-emitting diodes W-R on the first transfer substrate 300-R, while strengthening the adhesion between the adhesive film layer 420 and the red micro light-emitting diodes W-R. Thereby, the second transfer substrate 400 picks up the adhered red micro light-emitting diodes W-R. Thereby, as shown in FIGS. 6j and 6k, transfer the red micro light-emitting diodes W-R picked up by the first transfer substrate 300-R for the first time to the micro light-emitting diode region S-R corresponding to red on the second transfer substrate 400.

[0090] Next, as shown in FIGS. 6l and 6m, repeat the processes of the above steps (4) to (7) to adhere the red micro light-emitting diodes W-R to the micro light-emitting diode region S-R corresponding to red on the second transfer substrate 400 respectively.

[0091] Step (8) Align the second first transfer substrate 300-G corresponding to green with the wafer 200-G. As shown in FIGS. 4, 3b, and 7d, the shape of the first transfer substrate 300-G may be rectangular, for example, rectangular or square. In this way, first transfer alignment marks 320 may be provided at the four corners of the first transfer substrate 300-G. Further, element alignment marks 210 are also formed on the wafer 200-G. In this manner, control the first transfer alignment marks 320 and the element alignment marks 210 to be aligned, so that the adhesive structure 310 on the first transfer substrate 300-G is aligned one-to-one with the green micro light-emitting diodes W-G to be picked up on the wafer 200-G. Next, the adhesive structure 310 on the aligned first transfer substrate 300-G is adhesively bonded one-to-one with the green micro light-emitting diodes W-G to be picked up on the wafer 200-G, whereby the green micro light-emitting diodes W-G to be picked up are adhesively bonded to the adhesive structure 310.

[0092] Step (9) By means of a thermosetting process, separate the wafer 200-G from the green micro light-emitting diodes W-G to be picked up, while strengthening the adhesion between the adhesive structure 310 and the green micro light-emitting diodes W-G to be picked up. Thereby, as shown in FIG. 7e, the first transfer substrate 300-G picks up the adhered green micro light-emitting diodes W-G. In FIG. 7e, the dotted line portion of the wafer 200-G represents the green micro light-emitting diodes W-G picked up by the first transfer substrate 300-R.

[0093] Step (10) Align the first transfer substrate 300-G and the second transfer substrate 400. As shown in FIGS. 4, 5, 7e, and 7f, the shape of the second transfer substrate 400 may be, for example, rectangular and the same as the dimensions of the target substrate. In this way, second transfer alignment marks 420 may be provided at the four corners of the second transfer substrate 400. In this manner, control the first transfer alignment mark 320 and the second transfer alignment mark 420 to be aligned, so that the green micro light-emitting diodes W-G adhered to the first transfer substrate 300-G are aligned one-to-one with the adhesive film layer in the micro light-emitting diode region S-G corresponding to green in the second transfer substrate 400. Next, adhere the green micro light-emitting diodes W-G adhered to the aligned first transfer substrate 300-G one-to-one with the adhesive film layer in the micro light-emitting diode region S-G corresponding to green in the second transfer substrate 400, thereby adhering the green micro light-emitting diodes W-G to the adhesive film layer 410.

[0094] Step (11) By means of a hot press process, separate the first transfer substrate 300-G from the picked-up green micro light-emitting diodes W-G, while strengthening the adhesion between the adhesive film layer 420 and the green micro light-emitting diodes W-G. Thereby, the second transfer substrate 400 picks up the adhered green micro light-emitting diodes W-G. As shown in FIGS. 6l and 6m, the green micro light-emitting diodes W-G picked up by the first transfer substrate 300-G for the first time are transferred to the micro light-emitting diode region S-G corresponding to green in the second transfer substrate 400.

[0095] Next, as shown in FIGS. 6l and 6m, repeat the process of the above steps (8) to (11) to adhere the green micro light-emitting diodes W-G to the micro light-emitting diode region S-G corresponding to green in the second transfer substrate 400 respectively.

[0096] Similarly, in the case of blue, as shown in FIGS. 6l and 6m, referring to the processes of steps (4) to (11) above, a plurality of blue micro light-emitting diodes W-B on the wafer 200-B are picked up using the adhesive structure 310 on the third first transfer substrate 300-B corresponding to blue, and each time the picked-up blue micro light-emitting diode W-B is transferred to the micro light-emitting diode region S-B corresponding to blue in the second transfer substrate 400. As a result, blue micro light-emitting diodes W-B will be provided in all of the micro light-emitting diode regions S-B corresponding to blue in the second transfer substrate 400.

[0097] For the cross-sectional structure schematic diagrams of each step of this embodiment, reference can be made to the cross-sectional structure schematic diagrams of the above embodiment, and the details will not be described in detail here.

[0098] In another method for mass-transferring micro light-emitting diodes according to an embodiment of the present disclosure, modifications are made to the embodiments of the above embodiment. Only the differences between this embodiment and the above embodiment will be described, and the similarities will not be described in detail here.

[0099] In a specific implementation, the target substrate may include at least two target regions of the same size. The size of one second transfer substrate is approximately the same as the size of one target region. As an example, the target substrate includes two target regions of the same size. Or, the target substrate includes three target regions of the same size. Or, the target substrate includes four target regions of the same size. Of course, in actual application, the number of target regions included in the target substrate can be designed and determined according to the actual application environment. In this way, the transfer time of the transfer from the second transfer substrate to the target substrate can be reduced, the performance stability of the anisotropic conductive adhesive can be ensured, and the stability of the target substrate when adapting to the display panel can be improved.

[0100] In a specific implementation, the target regions included in the target substrate may be arranged in an array on the target substrate. Alternatively, the target regions included in the target substrate may be arranged on the target substrate in the first direction F1. Alternatively, the target regions included in the target substrate may be arranged on the target substrate in the second direction F2.

[0101] As an example, in a specific implementation, as shown in FIGS. 2a and 8, the target substrate 100 may include four target regions Y1, Y2, Y3, and Y4 of the same size, and the size of the second transfer substrate 400 is substantially the same as the size of the target region Y1.

[0102] In a specific implementation, in an embodiment of the present disclosure, the second transfer substrate 400 may further include an adhesive film layer 410 covering the second transfer substrate. The adhesive film layer 410 has micro-light emitting diode regions corresponding to different colors. Further, one micro-light emitting diode region corresponds to one sub-pixel of the target substrate 100. As an example, the adhesive film layer 410 has a micro-light emitting diode region S-R corresponding to red, a micro-light emitting diode region S-G corresponding to green, and a micro-light emitting diode region S-B corresponding to blue. Here, the micro-light emitting diode region S-R corresponds to the red sub-pixel SPX-R of the target substrate 100, the micro-light emitting diode region S-G corresponds to the red sub-pixel SPX-G of the target substrate 100, and the micro-light emitting diode region S-B corresponds to the red sub-pixel SPX-B of the target substrate 100.

[0103] In a specific implementation, the step of transferring each micro-light emitting diode on the second transfer substrate into the corresponding sub-pixel of the target substrate in a batch manner is sequentially aligning the second transfer substrate and the target region, and separating the second transfer substrate and the micro-light emitting diode each time alignment is performed, and may include transferring each micro-light emitting diode on the second transfer substrate into the corresponding sub-pixel of the target substrate in a batch manner.

[0104] Hereinafter, the process of the master transfer method will be illustrated with examples, but it is clear that the specific process is not limited thereto.

[0105] In the master transfer method according to the embodiments of the present disclosure, mainly the embodiments of the above steps (8) to (9) are modified. Hereinafter, the specific embodiments of the above steps (8) to (9) will be mainly described, and the remaining same steps will not be described in detail here. By the embodiments corresponding to FIGS. 6a to 6l or the embodiments corresponding to FIGS. 7a to 7g above, the second transfer substrate 400 shown in FIG. 9a is obtained. For all of the micro light-emitting diode regions S-R corresponding to red in the second transfer substrate 400, red micro light-emitting diodes W-R are adhered respectively. For all of the micro light-emitting diode regions S-G corresponding to green, green micro light-emitting diodes W-G are provided. For all of the micro light-emitting diode regions S-B corresponding to blue, blue micro light-emitting diodes W-B are provided.

[0106] Step (8): Align the target region Y1 of the second transfer substrate 400 and the target substrate 100, and align each red micro light-emitting diode W-R adhered to the second transfer substrate 400 with the red sub-pixels SPX-R in the target region Y1 one-to-one, and align each green micro light-emitting diode W-G adhered to the second transfer substrate 400 with the green sub-pixels SPX-G in the target region Y1 one-to-one, and then align each blue micro light-emitting diode W-B adhered to the second transfer substrate 400 with the blue sub-pixels SPX-B in the target region Y1 one-to-one.

[0107] Step (9) As shown in FIGS. 9b and 6o, by irradiating the second transfer substrate with a laser, the photo-decomposable adhesive loses its adhesiveness, separating the second transfer substrate from each micro light-emitting diode on the second transfer substrate. Next, by means of a thermosetting process, each micro light-emitting diode on the second transfer substrate is collectively transferred into the corresponding sub-pixel within the target region Y1, and under the action of pressure, the electrodes of each micro light-emitting diode are electrically connected to the anisotropic conductive adhesive within the corresponding sub-pixel. FIG. 9b is a schematic top view structure diagram, and FIG. 6o is a schematic cross-sectional structure diagram along the AA' direction of FIG. 9b.

[0108] Step (10) Next, according to the embodiments corresponding to FIGS. 6a to 6l or the embodiments corresponding to FIGS. 7a to 7g above, the second transfer substrate 400 shown in FIG. 9a is obtained. In all of the micro light-emitting diode regions S-R corresponding to red in the second transfer substrate 400, red micro light-emitting diodes W-R are respectively adhered. In all of the micro light-emitting diode regions S-G corresponding to green, green micro light-emitting diodes W-G are provided. In all of the micro light-emitting diode regions S-B corresponding to blue, blue micro light-emitting diodes W-B are provided.

[0109] Step (11) Align the second transfer substrate 400 with the target region Y2 of the target substrate 100, such that each red micro light-emitting diode W-R adhered to the second transfer substrate 400 is aligned one-to-one with the red sub-pixel SPX-R within the target region Y2 respectively, each green micro light-emitting diode W-G adhered to the second transfer substrate 400 is aligned one-to-one with the green sub-pixel SPX-G within the target region Y2 respectively, and each blue micro light-emitting diode W-B adhered to the second transfer substrate 400 is aligned one-to-one with the blue sub-pixel SPX-B within the target region Y2 respectively.

[0110] Step (12) As shown in FIGS. 9b and 6o, by irradiating the second transfer substrate with a laser, the photocurable adhesive loses its adhesiveness, and the second transfer substrate and each micro light-emitting diode on the second transfer substrate are separated. Next, by a thermosetting process, each micro light-emitting diode on the second transfer substrate is collectively transferred into the corresponding sub-pixel within the target region Y2, and by the action of pressure, the electrodes of each micro light-emitting diode are electrically connected to the anisotropic conductive adhesive within the corresponding sub-pixel.

[0111] Next, steps (10) to (12) of this embodiment are repeated to collectively transfer each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel within the target region Y3, and by the action of pressure, the electrodes of each micro light-emitting diode are electrically connected to the anisotropic conductive adhesive within the corresponding sub-pixel.

[0112] Next, steps (10) to (12) of this embodiment are repeated to collectively transfer each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel within the target region Y4, and by the action of pressure, the electrodes of each micro light-emitting diode are electrically connected to the anisotropic conductive adhesive within the corresponding sub-pixel.

[0113] Note that in this embodiment, for the cross-sectional structure schematic diagrams of each step, the cross-sectional structure schematic diagrams of the above embodiment can be referred to, and the details thereof will not be described in detail here.

[0114] Based on the same inventive structure, embodiments of the present disclosure further provide a mass transfer system for micro light-emitting diodes. As shown in FIGS. 4, 5, and 8, this system has a plurality of adhesive structures 310 and is configured to pick up the micro light-emitting diodes on the element substrate at least once using the plurality of adhesive structures 310 and transfer them onto the second transfer substrate 400 after each pick-up, a first transfer substrate 300 A second transfer substrate 400 configured to transfer each micro light-emitting diode on the second transfer substrate 400 in a batch into a corresponding sub-pixel in the target substrate, and one micro light-emitting diode on the second transfer substrate corresponds to one sub-pixel of the target substrate.

[0115] In a specific implementation, the number of micro light-emitting diodes placed on the second transfer substrate is greater than the number of micro light-emitting diodes placed on the first transfer substrate.

[0116] In a specific implementation, the dimensions of the second transfer substrate may be equal to or greater than the dimensions of the target substrate. As an example, the dimensions of the second transfer substrate 400 are larger than the dimensions of the target substrate 100. Alternatively, as shown in FIGS. 2a and 5, the dimensions of the second transfer substrate 400 may be approximately equal to the dimensions of the target substrate 100. In the actual process, due to process condition limitations and the influence of other factors, there may be some deviations. In the embodiments of the present disclosure, "equal" and "the same" mean "equal" and "the same" that conform to the range allowed by the error, or may substantially meet the above conditions, and in any case, they belong to the patent scope of the present disclosure.

[0117] In a specific implementation, the target substrate may include at least two target regions of the same dimension, and the dimensions of one second transfer substrate may be approximately the same as the dimensions of one target region. As an example, in a specific implementation, as shown in FIGS. 2a and 8, the target substrate 100 includes four target regions Y1, Y2, Y3, and Y4 of the same dimension, and the dimensions of the second transfer substrate 400 may be approximately the same as the dimensions of the target region Y1.

[0118] It should be noted that the operation process and specific implementation form of the mass transfer system are the same as those of the mass transfer method in the above embodiments. Therefore, for the operation process of the mass transfer system, reference can be made to the specific implementation form of the mass transfer method in the above embodiments, and details are not described here.

[0119] In the micro light-emitting diode mass transfer method and system according to the embodiments of the present disclosure, a plurality of adhesive structures are provided on the first transfer substrate, and the micro light-emitting diodes on the element substrate are picked up by these mutually independent adhesive structures. After picking up, they are transferred onto the second transfer substrate. In this way, the micro light-emitting diodes on the element substrate can be selectively transferred onto the second transfer substrate, improving efficiency. Furthermore, the adhesive structure can be used repeatedly. By picking up the micro light-emitting diodes at least once with the adhesive structure on the first transfer substrate, the adhesive structure is repeatedly used to transfer the micro light-emitting diodes on the element substrate onto the second transfer substrate, thereby reducing the number of first transfer substrates used and achieving cost reduction. Also, by collectively transferring each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel in the target substrate, multiple additional transfers are not required, improving efficiency.

[0120] Although the preferred embodiments of the present disclosure have been described, those skilled in the art can make other changes and modifications to these embodiments once they grasp the basic creative concept. Therefore, the appended claims are intended to cover the preferred embodiments and all changes and modifications belonging to the scope of the present disclosure.

[0121] Of course, those skilled in the art can make various changes and deformations to the embodiments of the present disclosure without departing from the spirit and scope of the embodiments of the present disclosure. Thus, the present disclosure is intended to include these changes and deformations if these modifications and deformations of the embodiments of the present disclosure belong to the scope of the claims of the present disclosure and the scope of equivalent technologies.

Claims

1. A mass transfer system for micro light-emitting diodes, comprising: a first transfer substrate configured to pick up at least one micro light-emitting diode on an element substrate at least once and transfer it onto a second transfer substrate after each pick-up; wherein the micro light-emitting diodes include at least two types of micro light-emitting diodes; the mass transfer system is configured, for each color of micro light-emitting diodes, to pick up a plurality of micro light-emitting diodes of the color on the element substrate using the first transfer substrate and transfer the picked-up micro light-emitting diodes of the color to a micro light-emitting diode region corresponding to the color on the second transfer substrate; the mass transfer system further includes a second transfer substrate; the mass transfer system separates the micro light-emitting diodes on the second transfer substrate so that, after aligning the second transfer substrate with a target substrate, at least two types of each micro light-emitting diode on the second transfer substrate are collectively transferred into corresponding sub-pixels on the target substrate; one micro light-emitting diode on the second transfer substrate corresponds to one sub-pixel of the target substrate; A mass transfer system for micro light-emitting diodes.

2. The first transfer substrate includes a plurality of adhesive structures; The first transfer substrate is configured, by the plurality of adhesive structures, to pick up at least one micro light-emitting diode on the element substrate at least once and transfer it to the second transfer substrate after each pick-up. The mass transfer system for micro light-emitting diodes according to Claim 1.

3. In a first direction, the width of the adhesive structure is smaller than the sum of the width of the micro light-emitting diode and the gap between two adjacent micro light-emitting diodes; In a second direction, the width of the adhesive structure is smaller than the sum of the width of the micro light-emitting diode and the gap between two adjacent micro light-emitting diodes; The first direction and the second direction are different directions extending along the plane where the first substrate is located. The mass transfer system for micro light-emitting diodes according to Claim 1.

4. The first transfer substrate is one, The master transfer system picks up the micro light-emitting diodes of the color on the element substrate multiple times using the first transfer substrate for each color of micro light-emitting diodes, and transfers the picked-up micro light-emitting diodes of the color each time to the micro light-emitting diode region corresponding to the color on the second transfer substrate. The master transfer system for micro light-emitting diodes according to claim 1.

5. The micro light-emitting diodes include red micro light-emitting diodes, green light-emitting diodes, and blue light-emitting diodes, The pixels of the target substrate include red sub-pixels, green sub-pixels, and blue sub-pixels. The master transfer system for micro light-emitting diodes according to claim 1.

6. Picking up the micro light-emitting diodes of the color to be picked up on the element substrate includes: Aligning the first transfer substrate and the element substrate, Adhering the adhesion structure on the aligned first transfer substrate to the micro light-emitting diodes of the color to be picked up on the element substrate in a one-to-one correspondence to pick up the micro light-emitting diodes of the color to be picked up on the element substrate on the first transfer substrate. The master transfer system for micro light-emitting diodes according to claim 2.

7. The shape of the first transfer substrate is rectangular, and first transfer alignment marks are provided at the four corners of the first transfer substrate. The element substrate is a wafer, and element alignment marks are formed on the wafer. The master transfer system aligns the first transfer alignment marks and the element alignment marks to align the adhesion structure on the first transfer substrate with the micro light-emitting diodes of the color to be picked up on the wafer in a one-to-one correspondence. The master transfer system for micro light-emitting diodes according to claim 6.

8. The second transfer substrate includes an adhesion film layer covering the second transfer substrate. After each pickup, transferring the micro light-emitting diode of the color to the micro light-emitting diode region corresponding to the color on the second transfer substrate, aligning the first transfer substrate and the second transfer substrate, adhering the micro light-emitting diode of the color on the aligned first transfer substrate to the micro light-emitting diode region corresponding to the color on the second transfer substrate in a one-to-one correspondence, separating the first transfer substrate and the micro light-emitting diode of the color on the first transfer substrate so as to transfer the micro light-emitting diode of the color to the micro light-emitting diode region corresponding to the color on the second transfer substrate, including, The micro light-emitting diode mass transfer system according to claim 1.

9. The shape of the second transfer substrate is rectangular, the same as the dimensions of the target substrate, and second transfer alignment marks are provided at the four corners of the second transfer substrate, The micro light-emitting diode mass transfer system controls to align the first transfer alignment mark and the second transfer alignment mark, so as to align the micro light-emitting diode of the color adhered to the first transfer substrate and the adhesive film layer in the micro light-emitting diode region corresponding to the color on the second transfer substrate in a one-to-one correspondence, The micro light-emitting diode mass transfer system according to claim 7.

10. The target substrate includes a plurality of sub-pixels, and each of the sub-pixels includes a pre-formed first electrode, a second electrode, and an anisotropic conductive adhesive respectively located on the side of the target substrate separated from the first electrode and the second electrode, simultaneously with or after separating the second transfer substrate and each micro light-emitting diode on the second transfer substrate, and further, electrically connecting the electrodes of the micro light-emitting diode separated from the second transfer substrate to the anisotropic conductive adhesive in the corresponding sub-pixel, The micro light-emitting diode mass transfer system according to claim 1.

11. The number of micro light-emitting diodes placed on the second transfer substrate is larger than the number of micro light-emitting diodes placed on the first transfer substrate. The micro light-emitting diode mass transfer system according to any one of claims 1 to 10.

12. The size of the second transfer substrate is equal to or larger than the size of the target substrate. The micro light-emitting diode mass transfer system according to any one of claims 1 to 10.

13. The target substrate includes at least two target regions of the same size. Transferring each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel on the target substrate in a batch includes: Sequentially aligning the second transfer substrate and the target region, and separating the second transfer substrate and the micro light-emitting diodes each time they are aligned, so as to transfer each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixel on the target substrate in a batch. The micro light-emitting diode mass transfer system according to any one of claims 1 to 10.

14. One of the first transfer substrates corresponds to the micro light-emitting diodes of one color. Using a plurality of adhesive structures on the first transfer substrate to pick up the micro light-emitting diodes on the element substrate at least once and transfer them onto the second transfer substrate after each pick-up includes: For the micro light-emitting diodes of each color, using the first transfer substrate corresponding to the color to pick up the micro light-emitting diodes of the color on the element substrate multiple times, and transferring the micro light-emitting diodes of the color onto the micro light-emitting diode region corresponding to the color on the second transfer substrate after each pick-up. The micro light-emitting diode mass transfer system according to any one of claims 1 to 10.

15. Picking up the micro light-emitting diodes of the color to be picked up on the element substrate includes: Aligning the first transfer substrate and the element substrate. Adhering the adhesion structure on the aligned first transfer substrate to the micro light-emitting diodes of the color to be picked up on the element substrate in a one-to-one correspondence, Separating the element substrate and the micro light-emitting diodes of the color to be picked up by a laser or a thermal curing process, so that the first transfer substrate picks up the adhered micro light-emitting diodes of the color, The micro light-emitting diode mass transfer system according to claim 2.

16. The material of the adhesion structure includes a thermal decomposition adhesive, Separating the first transfer substrate and the micro light-emitting diodes of the color on the first transfer substrate, Includes separating the first transfer substrate and the micro light-emitting diodes of the color on the first transfer substrate by a hot press process, The micro light-emitting diode mass transfer system according to claim 15.

17. The material of the adhesion structure includes a photo-decomposable adhesive, Separating the first transfer substrate and the micro light-emitting diodes of the color on the first transfer substrate, Separating the first transfer substrate and the micro light-emitting diodes of the color on the first transfer substrate by a laser, The micro light-emitting diode mass transfer system according to claim 15.

18. The material of the adhesive film layer on the second transfer substrate includes a thermal decomposition adhesive, Separating the second transfer substrate and the micro light-emitting diodes, Includes separating the second transfer substrate and each micro light-emitting diode on the second transfer substrate by a hot press process, The micro light-emitting diode mass transfer system according to claim 8 or claim 9.

19. The material of the adhesive film layer on the second transfer substrate includes a photo-decomposable adhesive, Separating the second transfer substrate and the micro light-emitting diodes, Includes separating the second transfer substrate and each micro light-emitting diode on the second transfer substrate by a laser, The micro light-emitting diode mass transfer system according to claim 8 or claim 9.

20. A micro light-emitting diode mass transfer method, Providing a device substrate formed with a plurality of micro light-emitting diodes; Using a plurality of adhesive structures on a first transfer substrate to pick up at least once the micro light-emitting diodes on the device substrate, and transferring, after each pick-up, the micro light-emitting diodes on the device substrate onto a second transfer substrate for selectively transferring the micro light-emitting diodes on the device substrate onto the second transfer substrate; Collectively transferring each micro light-emitting diode of at least two colors on the second transfer substrate into corresponding sub-pixels on a target substrate, One micro light-emitting diode on the second transfer substrate corresponds to one sub-pixel of the target substrate; The micro light-emitting diodes include micro light-emitting diodes of at least two colors; Using a plurality of adhesive structures on the first transfer substrate to pick up at least once the micro light-emitting diodes on the device substrate and transferring them onto the second transfer substrate each time they are picked up means that: For each color of micro light-emitting diodes, using the first transfer substrate to pick up multiple times the micro light-emitting diodes of that color on the device substrate, and transferring the micro light-emitting diodes of that color picked up each time into the micro light-emitting diode region corresponding to that color on the second transfer substrate; Collectively transferring each micro light-emitting diode of at least two colors on the second transfer substrate into corresponding sub-pixels on a target substrate means that: Aligning the second transfer substrate with the target substrate; Separating the second transfer substrate from the micro light-emitting diodes in order to collectively transfer each micro light-emitting diode on the second transfer substrate into the corresponding sub-pixels on the target substrate; A method for mass transfer of micro light-emitting diodes.

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