Mass transfer method, functional film for mass transfer and method for manufacturing the same

Abstract

The present application relates to a mass transfer method and a functional film for mass transfer and a method for manufacturing the same. The mass transfer method includes: laminating the functional film to a temporary substrate, coating a pyrolytic adhesive on a first surface, allowing the pyrolytic adhesive to flow under the restriction of a plurality of first microstructures, and solidifying the pyrolytic adhesive; laminating the temporary substrate to an LED on the temporary substrate, so that the pyrolytic adhesive is glued to the LED on the temporary substrate, the bonding force between the pyrolytic adhesive and the LED is greater than the bonding force between the first adhesive layer on the temporary substrate and the LED, and peeling off the temporary substrate; and bonding the LED on the temporary substrate to a circuit backplane, so that the LED and the circuit backplane are welded, heating to melt the pyrolytic adhesive, so that the bonding force between the LED and the circuit backplane is greater than the bonding force between the LED and the pyrolytic adhesive, and peeling off the temporary substrate. Ordinary pyrolytic adhesive can be used to achieve mass transfer without taking away the LED when peeling off the temporary substrate and the temporary substrate, thereby ensuring the transfer of the LED and improving the yield rate.

Description

Technical Field

[0001] The present application relates to the technical field of light-emitting diode manufacturing processes, and in particular to a mass transfer method, a functional film for mass transfer, and a method for manufacturing the same. Background Art

[0002] Micro-LED (Micro-light-emitting diode) is a next-generation display technology. Compared to existing liquid crystal displays, it offers higher photoelectric efficiency, higher brightness, higher contrast, and lower power consumption. It can also be combined with flexible panels to achieve flexible displays, offering broad application prospects.

[0003] The key to Micro-LED production lies in the mass transfer process, which mainly includes the growth of LEDs, transfer to a temporary substrate, transfer to a transient substrate, and bonding to a circuit backplane. During the transfer of the LEDs from the temporary substrate to the transient substrate, the LEDs are connected to the temporary substrate via a first adhesive layer, and the LEDs are bonded to the transient substrate using a second adhesive layer. The second adhesive layer must have a greater adhesive strength than the first layer to allow the LEDs to be peeled from the temporary substrate. During the transfer of the LEDs from the transient substrate to the circuit backplane, the welding force between the LEDs and the circuit backplane must be greater than the bonding force between the LEDs and the transient substrate.

[0004] Currently, it is difficult to find materials for the adhesive layer that can meet this requirement, resulting in a low yield rate for mass transfer.

[0005] Therefore, how to provide a simple method with high yield to realize the transfer of LEDs from a temporary substrate to a transient substrate, and how to realize the transfer of LEDs from a transient substrate to a circuit backplane are problems that need to be solved urgently. Summary of the Invention

[0006] In view of the above-mentioned deficiencies in the prior art, the purpose of this application is to provide a mass transfer method and a functional film for mass transfer and a method for manufacturing the same, aiming to solve the problem of providing a simple way with high yield to realize the transfer of LEDs from a temporary substrate to a transient substrate, and to realize the transfer of LEDs from a transient substrate to a circuit backplane.

[0007] A functional film for mass transfer, the functional film being used to be bonded to a temporary substrate, the surface of the functional film facing away from the temporary substrate being a first surface, the first surface being formed with a plurality of first microstructures, the first surface being used to coat a pyrolytic adhesive, the pyrolytic adhesive flowing under the restriction of the plurality of first microstructures.

[0008] By forming multiple first microstructures, the flow of the pyrolytic adhesive can be restricted, so that the pyrolytic adhesive coated on the first surface forms a regular shape, which can correspond to the bonding of LEDs, thereby achieving one-time transfer of all LEDs or multiple transfers.

[0009] Optionally, a plurality of the first microstructures are distributed in an array on the first surface. The first microstructures are used to restrict the flow of the pyrolytic adhesive, making the shape of the pyrolytic adhesive curing controllable. By providing the first microstructures distributed in an array, when the pyrolytic adhesive flows, the first microstructures are all around the pyrolytic adhesive to restrict the pyrolytic adhesive, thereby preventing disordered diffusion of the pyrolytic adhesive and effectively restricting the flow.

[0010] Optionally, the first microstructures are protrusions or grooves. Compared to a completely flat first surface, protrusions or grooves are provided on the first surface to form an uneven structure. This allows the pyrolytic adhesive to be blocked by the protrusions or flow into the grooves. The grooves also restrict the flow of the pyrolytic adhesive, preventing disordered diffusion of the pyrolytic adhesive on the first surface. The protrusions or grooves are simple in structure and easy to manufacture.

[0011] Optionally, the material of the functional film is a silicone system or an acrylic system.

[0012] Based on the same inventive concept, the present application also provides a method for manufacturing a functional film for mass transfer, comprising:

[0013] providing a mold, the mold comprising a substrate and a plurality of second microstructures located on the substrate;

[0014] coating a functional material on the substrate and curing the functional material to form a functional film;

[0015] The surface where the functional film is bonded to the substrate is the first surface, and the first surface is formed with a plurality of first microstructures that are complementary to the plurality of second microstructures.

[0016] The functional film is made through a mold, specifically by coating a functional material and curing it to form a functional film. The second microstructure on the mold will be reversely printed on the functional film to form the first microstructure. The functional film can then be peeled off from the mold to obtain the desired functional film structure. The manufacturing process is simple and easy to operate.

[0017] Optionally, the method further includes forming the substrate and the plurality of second microstructures on a single silicon plate through an etching process. The second microstructures are etched from a single silicon plate, and the substrate and the plurality of second microstructures form an integrated structure, which has good structural strength. Due to the extremely small size of LEDs, particularly Micro-LEDs, etching the silicon plate through the etching process can achieve the engraving of tiny structures, facilitating the subsequent fabrication of functional films.

[0018] Optionally, the functional material is a silicone system or an acrylic system.

[0019] Based on the same inventive concept, the present application also provides a mass transfer method, comprising:

[0020] Laminating the functional film described in any one of the aforementioned embodiments to a temporary substrate, coating a pyrolytic adhesive on the first surface, allowing the pyrolytic adhesive to flow under the restriction of the plurality of first microstructures, and curing the pyrolytic adhesive;

[0021] Laminating the temporary substrate to the LED on the temporary substrate so that the pyrolytic adhesive is bonded to the LED on the temporary substrate, the adhesive force between the pyrolytic adhesive and the LED being greater than the adhesive force between the first adhesive layer on the temporary substrate and the LED, and peeling off the temporary substrate;

[0022] The LED on the temporary substrate is bonded to a circuit backboard to weld the LED to the circuit backboard, and the pyrolytic adhesive is melted by heating so that the welding force between the LED and the circuit backboard is greater than the adhesive force between the LED and the pyrolytic adhesive, and the temporary substrate is peeled off.

[0023] By setting a functional film, a pyrolytic adhesive is coated on the first surface of the functional film. The flow of the pyrolytic adhesive is restricted by the first microstructure. The bonding force between the solidified pyrolytic adhesive and the LED is greater than the bonding force between the first adhesive layer of the temporary substrate and the LED. When the temporary substrate is peeled off, the LED can be transferred to the transient substrate. After the transient substrate is bonded to the circuit backplane, the pyrolytic adhesive is melted by heating, so that the welding force between the LED and the circuit backplane is greater than the bonding force between the pyrolytic adhesive and the LED. When the transient substrate is peeled off, the LED can be transferred to the circuit backplane. Ordinary pyrolytic adhesive can be used to achieve mass transfer without taking away the LED when peeling off the temporary substrate and the transient substrate, thereby ensuring the transfer of the LED and improving the yield rate.

[0024] Optionally, the first surface includes a plurality of first areas and a second area, and the first areas and the second areas are both provided with a plurality of the first microstructures, the first areas correspond to the LEDs to be transferred, and the second areas correspond to the LEDs that are not transferred temporarily; coating the thermolytic adhesive on the first surface includes: coating the thermolytic adhesive on the first areas.

[0025] By setting the first area to be coated with pyrolytic adhesive and transferring the LED through the pyrolytic adhesive in the first area, the LED on the temporary substrate can be selectively transferred in multiple times, so that the LEDs on the growth substrate and the temporary substrate can be arranged more densely, more LEDs can be grown at one time, and the utilization efficiency of the growth substrate and the temporary substrate can be improved.

[0026] Optionally, the shape of the first area is any one of a rectangle, a circle, and an ellipse. The shape of the first area is the shape of the cured pyrolytic adhesive after coating. These shapes are relatively simple and do not require complicated settings for the pyrolytic adhesive coating operation, and are easy to operate.

[0027] Optionally, a plurality of the first regions are distributed in an array on the first surface, so as to correspond one to one with the LEDs, and all the LEDs on the temporary substrate can be transferred to the circuit backplane after a few transfers. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A flowchart of a method for mass transfer according to an embodiment of the present invention is provided;

[0029] Figure 2 A schematic structural diagram of a step of a mass transfer method according to an embodiment;

[0030] Figure 3 A schematic structural diagram of a step of a mass transfer method according to an embodiment;

[0031] Figure 4 A schematic structural diagram of a step of a mass transfer method according to an embodiment;

[0032] Figure 5 A schematic structural diagram of a step of a mass transfer method according to an embodiment;

[0033] Figure 6 A schematic structural diagram of a step of a mass transfer method according to an embodiment;

[0034] Figure 7 A schematic structural diagram of a step of a mass transfer method according to an embodiment;

[0035] Figure 8 A schematic structural diagram of a step of a mass transfer method according to an embodiment;

[0036] Figure 9 A schematic structural diagram of a step of a mass transfer method according to an embodiment;

[0037] Figure 10 A schematic structural diagram of a step of a mass transfer method according to an embodiment;

[0038] Figure 11 A structural diagram of a step of a mass transfer method according to an embodiment.

[0039] Description of reference numerals:

[0040] 10-growth substrate;

[0041] 20-LED, 21-epitaxial structure, 22-P electrode, 23-N electrode;

[0042] 30-temporary substrate;

[0043] 40-first adhesive layer;

[0044] 50-transient substrate;

[0045] 60-functional film, 61-first surface, 62-first microstructure;

[0046] 70-pyrolysis glue;

[0047] 80-circuit backboard, 81-first soldering pad, 82-second soldering pad;

[0048] 90-substrate, 91-second microstructure. DETAILED DESCRIPTION

[0049] To facilitate understanding of the present application, a more comprehensive description of the present application will be provided below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0051] The key to Micro-LED production lies in the mass transfer process, which mainly includes the growth of LEDs, transfer to a temporary substrate, transfer to a transient substrate, and bonding to a circuit backplane. During the transfer of the LEDs from the temporary substrate to the transient substrate, the LEDs are connected to the temporary substrate via a first adhesive layer, and the LEDs are bonded to the transient substrate using a second adhesive layer. The second adhesive layer must have a greater adhesive strength than the first layer to allow the LEDs to be peeled from the temporary substrate. During the transfer of the LEDs from the transient substrate to the circuit backplane, the welding force between the LEDs and the circuit backplane must be greater than the bonding force between the LEDs and the transient substrate.

[0052] Currently, it is difficult to find materials for the adhesive layer that can meet this requirement, resulting in a low yield rate for mass transfer.

[0053] Therefore, how to provide a simple method with high yield to realize the transfer of LEDs from a temporary substrate to a transient substrate, and how to realize the transfer of LEDs from a transient substrate to a circuit backplane are problems that need to be solved urgently.

[0054] Based on this, the present application hopes to provide a solution that can solve the above technical problems, the details of which will be explained in the subsequent embodiments.

[0055] Please refer to Figure 1 The embodiment of the present application provides a mass transfer method, including steps S10-S30. The mass transfer process includes steps such as LED growth, transfer, and bonding.

[0056] Please refer to Figure 2 , LED20 is grown on a growth substrate 10, the growth substrate 10 may be sapphire or the like, and LED20 may be a Micro-LED20 (Micro-light-emitting diode). LED20 may specifically include an epitaxial structure 21, a P electrode 22 and an N electrode 23. The epitaxial structure 21 is formed on the growth substrate 10, and the P electrode 22 and the N electrode 23 are formed on the epitaxial structure 21. There may be multiple LED20, and the multiple LED20 are arranged at intervals. Optionally, LED20 includes a red LED20, a green LED20, and a blue LED20. Optionally, the same type of LED20 may be grown on the same growth substrate 10, and the red LED20, green LED20, and blue LED20 may be grown separately by three growth substrates 10. Optionally, multiple types of LED20 may be grown on the same growth substrate 10, and the red LED20, green LED20, and blue LED20 may be grown simultaneously by one growth substrate 10.

[0057] Please refer to Figure 3 The growth substrate 10 is bonded to the temporary substrate 30, and the LED 20 on the growth substrate 10 is bonded to the first adhesive layer 40 on the temporary substrate 30, specifically the P electrode 22 and the N electrode 23 are bonded to the first adhesive layer 40. The temporary substrate 30 can be made of glass, sapphire, etc.

[0058] Please refer to Figure 3 and Figure 4 The growth substrate 10 may be peeled off by laser lift-off (LLO), specifically, laser is irradiated on the growth substrate 10 so that the epitaxial structure 21 of the LED 20 reacts with the laser and can be separated from the growth substrate 10 .

[0059] Please refer to Figure 5 , step S10 of the embodiment of the present application: attaching the functional film 60 to the temporary substrate 50, coating the pyrolytic adhesive 70 on the first surface 61 of the functional film 60, forming a plurality of first microstructures 62 on the first surface 61, and the pyrolytic adhesive 70 flows under the restriction of the plurality of first microstructures 62, so that the pyrolytic adhesive 70 is solidified.

[0060] Specifically, the transient substrate 50 may be quartz, glass, sapphire, etc. The functional film 60 may have adhesive properties, and the functional film 60 and the transient substrate 50 may be fixed by adhesive force. Providing the functional film 60 can make the pyrolytic adhesive 70 better formed on the functional film 60, and can achieve the adjustment of the adhesive force of the pyrolytic adhesive 70, which will be described later and will not be discussed here. If there is no functional film 60, the pyrolytic adhesive 70 is on the transient substrate 50, and the adhesive force of the pyrolytic adhesive 70 is fixed and difficult to adjust, making it difficult to achieve the purpose of the invention of this application. The functional film 60 and the transient substrate 50 are detachable structures. When the functional film 60 needs to be replaced after being used multiple times, the functional film 60 can be separated from the transient substrate 50 and replaced with a new functional film 60.

[0061] Please refer to Figure 5 In step S20 of the embodiment of the present application, the temporary substrate 50 is bonded to the LED 20 on the temporary substrate 30, so that the pyrolytic adhesive 70 is bonded to the LED 20 on the temporary substrate 30, and the bonding force between the pyrolytic adhesive 70 and the LED 20 is greater than the bonding force between the first adhesive layer 40 on the temporary substrate 30 and the LED 20. Figure 6 , peeling off the temporary substrate 30.

[0062] For details, please refer to Figure 5 and Figure 6 The bonding strength between the functional film 60 and the temporary substrate 50 is greater than the bonding strength between the LED 20 and the first adhesive layer 40. This allows the functional film 60 and the temporary substrate 50 to remain attached and not separate when the temporary substrate 30 is peeled off. The bonding strength between the pyrolytic adhesive 70 and the functional film 60 is also greater than the bonding strength between the LED 20 and the first adhesive layer 40. This allows the pyrolytic adhesive 70 and the functional film 60 to remain connected and not separate when the temporary substrate 30 is peeled off.

[0063] The thermal adhesive 70 is connected to the epitaxial structure 21 of the LED 20 . After the temporary substrate 30 is peeled off, the P electrode 22 and the N electrode 23 are exposed. The P electrode 22 and the N electrode 23 are used for welding with corresponding electrodes on the circuit backplane 80 .

[0064] The temporary substrate 30 can be peeled off mechanically. Due to the different adhesive forces on both sides of the LED 20 , the LED 20 will be separated from the temporary substrate 30 during the mechanical peeling process and transferred to the transient substrate 50 .

[0065] Please refer to Figure 7 In step S30 of the present embodiment, the LED 20 on the temporary substrate 50 is bonded to the circuit backboard 80, thereby soldering the LED 20 to the circuit backboard 80. The pyrolytic adhesive 70 is heated to melt, so that the soldering force between the LED 20 and the circuit backboard 80 is greater than the adhesive force between the LED 20 and the pyrolytic adhesive 70. Subsequently, the temporary substrate 50 is peeled off, and the LED 20 is transferred to the circuit backboard 80.

[0066] Specifically, when LED 20 is soldered to circuit backplane 80, the P electrode 22 and N electrode 23 of LED 20 are soldered to corresponding pads on circuit backplane 80, i.e., P electrode 22 is soldered to first pad 81, and N electrode 23 is soldered to second pad 82. After soldering is completed, the temporary substrate 50 needs to be peeled off. The solidified pyrolytic adhesive 70 has a strong bonding force with LED 20, which may be greater than the bonding force between LED 20 and circuit backplane 80. When the temporary substrate 50 is peeled off, the LED 20 may be carried away, and the mass transfer cannot be completed. Therefore, a step of heating the pyrolytic adhesive 70 is provided to melt the pyrolytic adhesive 70. The bonding force between the melted pyrolytic adhesive 70 and LED 20 is significantly reduced, which can ensure that the bonding force between LED 20 and circuit backplane 80 is greater than the bonding force between the pyrolytic adhesive 70 and LED 20. This ensures that the LED 20 is not carried away when the temporary substrate 50 is peeled off, thereby improving the yield rate of mass transfer.

[0067] The temporary substrate 50 can be mechanically peeled off. Due to the different adhesive strengths on both sides of the LED 20, the LED 20 is separated from the temporary substrate 50 during mechanical peeling and transferred to the circuit backplane 80. The temporary substrate 50 and the functional film 60 are peeled off together, and some pyrolytic adhesive 70 may remain on the functional film 60. The temporary substrate 50 and the functional film 60 together form a transfer head.

[0068] When the next mass transfer is performed, the loss of the pyrolytic adhesive 70 can be checked. Specifically, AOI (Automated Optical Inspection) can be used for inspection, and the missing parts can be re-coated to meet the process requirements.

[0069] The mass transfer method of the embodiment of the present application is to set a functional film 60, and coat a pyrolytic adhesive 70 on the first surface 61 of the functional film 60. The pyrolytic adhesive 70 is restricted in flow by the first microstructure 62. The bonding force between the solidified pyrolytic adhesive 70 and the LED 20 is greater than the bonding force between the first adhesive layer 40 of the temporary substrate 30 and the LED 20. When the temporary substrate 30 is peeled off, it can ensure that the LED 20 is transferred to the temporary substrate 50. After the temporary substrate 50 is bonded to the circuit backboard 80, the pyrolytic adhesive 70 is heated to melt, so that the welding force between the LED 20 and the circuit backboard 80 is greater than the bonding force between the pyrolytic adhesive 70 and the LED 20. When the temporary substrate 50 is peeled off, it can ensure that the LED 20 is transferred to the circuit backboard 80. Ordinary pyrolytic adhesive 70 can be used to achieve mass transfer without taking away the LED 20 when peeling the temporary substrate 30 and the temporary substrate 50, thereby ensuring the transfer of the LED 20 and improving the yield rate.

[0070] Please refer to Figure 5 、 Figures 9 to 11The mass transfer method of the embodiment of the present application also includes a step of making a functional film: forming a plurality of first microstructures 62 on the first surface 61 of the functional film 60, the first surface 61 being the surface of the functional film 60 facing away from the temporary substrate 50; and coating the first surface 61 with a pyrolytic adhesive 70, which flows under the restriction of the plurality of first microstructures 62.

[0071] Optionally, the temporary substrate 50 can transfer all LEDs 20 on the temporary substrate 30 at one time, and in this case, the pyrolytic adhesive 70 can be coated on the entire first surface 61 .

[0072] Optionally, the temporary substrate 50 transfers the LEDs 20 on the temporary substrate 30 in multiple times, and selectively picks up some of the LEDs 20 each time. Figure 5 and Figure 6 The figure shows a structure diagram of one of the transfers of LEDs 20 on the temporary substrate 30 by the temporary substrate 50. In this case, the pyrolytic adhesive 70 may not be applied to the entire first surface 61, but may be applied to the corresponding position of the LED 20 to be transferred, that is, to a portion of the first surface 61.

[0073] Due to the provision of the first microstructure 62, regardless of whether the pyrolytic adhesive 70 is coated on the entire first surface 61 or a portion of the first surface 61, the first microstructure 62 will restrict the flow of the pyrolytic adhesive 70. After the pyrolytic adhesive 70 is cured, the pyrolytic adhesive 70 usually forms a regular shape and does not spread without boundaries.

[0074] By providing a plurality of first microstructures 62 , the flow of the pyrolytic adhesive 70 is restricted so that the pyrolytic adhesive 70 coated on the first surface 61 forms a regular shape, which can be bonded to the LEDs 20 , thereby transferring all the LEDs 20 at one time or in multiple times.

[0075] Please refer to Figure 5 and Figure 6 As mentioned above, the pyrolytic adhesive 70 can be applied to the entire first surface 61, or to a portion of the first surface 61. For the pyrolytic adhesive 70 applied to a portion of the first surface 61, the first surface 61 includes a plurality of first regions and a second region, which together constitute the first surface 61. The first region and the second region (i.e., the entire surface of the first surface 61) are both provided with a plurality of first microstructures 62. The first region corresponds to the LED 20 to be transferred, and the second region corresponds to the LED 20 not yet transferred. Figure 5 and Figure 11 , the pyrolytic adhesive 70 is coated on the first area but not on the second area.

[0076] Since the first microstructure 62 on the first surface 61 has a restrictive effect on the flow of the pyrolytic adhesive 70, when the pyrolytic adhesive 70 is applied to the first area, the shape of the pyrolytic adhesive 70 after curing is roughly consistent with the shape of the first area due to the effect of the first microstructure 62. The position of the first area corresponds to the position of the LED 20 on the temporary substrate 30, as shown in FIG. Figure 5 and Figure 6 As shown, if the temporary substrate 50 is used to transfer the LEDs 20 from the temporary substrate 30 in three steps, two adjacent first regions are separated by two LEDs 20. After the first transfer is complete, during the second transfer, the temporary substrate 50 is moved so that the first region corresponds to the position of the LED 20 adjacent to the first transferred LED 20, and so on, until all LEDs 20 have been transferred in the third transfer. The dimensions of the first region are roughly the same as those of the LED 20, allowing the thermal adhesive 70 to adhere to the entire surface of the LED 20, thereby increasing the bonding strength between the thermal adhesive 70 and the LED 20.

[0077] By setting the first area to be coated with pyrolytic adhesive 70 and the second area not to be coated with pyrolytic adhesive 70, the LED20 can be transferred through the pyrolytic adhesive 70 in the first area, and the LED20 on the temporary substrate 30 can be selectively transferred in multiple times, so that the LED20 on the growth substrate 10 and the temporary substrate 30 can be arranged more densely, more LED20 can be grown at one time, and the utilization efficiency of the growth substrate 10 and the temporary substrate 30 is improved.

[0078] Optionally, the first region may be shaped like a rectangle, a circle, or an ellipse. The rectangle may be a square, a rectangle, or the like. The shape of the first region described above, i.e., the shape of the cured pyrolytic adhesive 70 after application, is relatively simple and does not require complex settings for the application of the pyrolytic adhesive 70, making it easy to operate.

[0079] Optional, please refer to Figures 5 to 7 and Figure 11 The plurality of first regions are distributed in an array on the first surface 61. Since the LEDs 20 grown on the growth substrate 10 are usually distributed in an array, and the LEDs 20 transferred to the temporary substrate 30 are also usually distributed in an array, the plurality of first regions are distributed in an array so that they correspond one to one with the LEDs 20. This allows all the LEDs 20 on the temporary substrate 30 to be transferred to the circuit backplane 80 after a few transfers.

[0080] Optional, please refer to Figure 11A plurality of first microstructures 62 are arranged in an array on the first surface 61. The first microstructures 62 are used to restrict the flow of the pyrolytic adhesive 70, so that the shape of the cured pyrolytic adhesive 70 can be controlled. By providing the first microstructures 62 in an array, when the pyrolytic adhesive 70 flows, the first microstructures 62 are all around the pyrolytic adhesive 70 to restrict the flow, thereby preventing the disordered diffusion of the pyrolytic adhesive 70 and effectively restricting the flow.

[0081] Optionally, the first microstructures 62 are protrusions or grooves. Compared to a completely flat first surface 61, protrusions or grooves are provided on the first surface 61 to form an uneven structure. When the pyrolytic adhesive 70 flows, it is blocked by the protrusions or flows into the grooves. The grooves also restrict the flow of the pyrolytic adhesive 70, preventing the pyrolytic adhesive 70 from spreading disorderly on the first surface 61. The protrusions or grooves are simple in structure and easy to manufacture.

[0082] In one embodiment, please refer to Figures 8 to 10 The mass transfer method further includes a step of making a functional film 60, specifically including: Figure 8 , providing a mold, the mold including a substrate 90 and a plurality of second microstructures 91 located on the substrate 90; please refer to Figures 8 to 10 , a functional material is coated on the substrate 90 and solidified to form a functional film 60; wherein the surface where the functional film 60 is bonded to the substrate 90 is a first surface 61, and a plurality of first microstructures 62 complementary to the second microstructures 91 are formed on the first surface 61.

[0083] Optionally, the second microstructure 91 may be a protrusion or a groove, and the first microstructure 62 may be a groove or a protrusion complementary thereto.

[0084] The functional film 60 is manufactured through a mold, specifically by coating a functional material and solidifying it to form the functional film 60. The second microstructure 91 on the mold will be reversely printed on the functional film 60 to form the first microstructure 62. The functional film 60 can then be peeled off from the mold to obtain the desired structure of the functional film 60. The manufacturing process is simple and easy to operate.

[0085] Optional, please refer to Figure 8 , a substrate 90 and a plurality of second microstructures 91 are formed on a whole silicon plate through an etching process. Figure 8 The substrate 90 and the multiple raised second microstructures 91 thereon are formed by etching a silicon plate. The substrate 90 and the multiple second microstructures 91 are an integrated structure with good structural strength. Due to the size of LED20, especially the extremely small size of Micro-LED20, etching the silicon plate through an etching process can achieve the engraving of tiny structures, which can facilitate the production of subsequent functional films 60.

[0086] Optionally, the functional material is a silicone or acrylic system. For example, the functional material is PDMS (Polydimethylsiloxane), which has a series of silicone properties, such as being a colorless and transparent liquid, having a wide viscosity range, high and low temperature resistance, weather resistance, radiation resistance, low surface tension, high compressibility, resistance to oxygen plasma, high insulation, hydrophobicity, high gloss, and being inert to other materials, chemically and physiologically inert. Therefore, it can be used as a good material for the functional film 60.

[0087] The embodiment of the present application also provides a functional film for mass transfer. For the relevant features of the functional film, please refer to the above description and will not be repeated here.

[0088] It should be understood that the application of this application is not limited to the above examples. For ordinary technicians in this field, they can make improvements or changes based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. A functional film for mass transfer, characterized in that: The functional film is used to be attached to a temporary substrate. The surface of the functional film facing away from the temporary substrate is a first surface. The first surface is formed with a plurality of first microstructures. The first surface is used to coat a pyrolytic adhesive. The pyrolytic adhesive flows under the restriction of the plurality of first microstructures. The first surface includes a plurality of first areas spaced apart and a second area adjacent to the first area. The first area and the second area are both provided with a plurality of the first microstructures. The pyrolytic adhesive is coated on the first area. The first area is used to correspond to the LED to be transferred.

2. The functional film according to claim 1, wherein A plurality of the first microstructures are distributed in an array on the first surface.

3. The functional film according to claim 1 or 2, characterized in that The first microstructure is a protrusion or a groove.

4. The functional film according to claim 1 or 2, characterized in that The material of the functional film is a silicone system or an acrylic system.

5. A method for manufacturing a functional film for mass transfer, characterized in that: Used to prepare the functional film for mass transfer according to any one of claims 1 to 4, comprising: providing a mold, the mold comprising a substrate and a plurality of second microstructures located on the substrate; coating a functional material on the substrate and curing the functional material to form a functional film; The surface where the functional film is bonded to the substrate is the first surface, and the first surface is formed with a plurality of first microstructures that are complementary to the plurality of second microstructures.

6. The method for producing a functional film according to claim 5, wherein: The method further includes: forming the substrate and a plurality of the second microstructures on a whole silicon plate by an etching process.

7. The method for producing a functional film according to claim 6, wherein: The functional material is a silicone system or an acrylic system.

8. A mass transfer method, characterized in that: include: laminating the functional film for mass transfer according to any one of claims 1 to 4 to a temporary substrate, coating a pyrolytic adhesive on the first surface, allowing the pyrolytic adhesive to flow under the restriction of the plurality of first microstructures, and curing the pyrolytic adhesive; Laminating the temporary substrate to the LED on the temporary substrate so that the pyrolytic adhesive is bonded to the LED on the temporary substrate, the adhesive force between the pyrolytic adhesive and the LED being greater than the adhesive force between the first adhesive layer on the temporary substrate and the LED, and peeling off the temporary substrate; The LED on the temporary substrate is bonded to a circuit backboard to weld the LED to the circuit backboard, and the pyrolytic adhesive is melted by heating so that the welding force between the LED and the circuit backboard is greater than the adhesive force between the LED and the pyrolytic adhesive, and the temporary substrate is peeled off.

9. The method for mass transfer according to claim 8, wherein: The first surface includes a plurality of first areas and a second area, each of the first areas and the second area is provided with a plurality of the first microstructures, the first areas correspond to the LEDs to be transferred, and the second areas correspond to the LEDs not yet transferred; The step of coating the first surface with a pyrolytic adhesive comprises: The pyrolytic adhesive is applied to the first region.

10. The mass transfer method according to claim 9, wherein: A plurality of the first regions are distributed in an array on the first surface.

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