Micro-LED transfer substrate and device

Abstract

The invention discloses a Micro-LED (Light Emitting Diode) transfer substrate and a Micro-LED transfer device. The transfer substrate includes: a base; the conductive layer is arranged on one side of the substrate and comprises at least one through hole; the transfer adhesive layer is arranged on one side, far away from the substrate, of the conductive layer and is used for transferring the Micro-LED; the laser light source is arranged on the side, away from the conductive layer, of the substrate and used for emitting laser, and the laser penetrates through the through hole and irradiates the transfer adhesive layer; the orthographic projection of the through hole on the substrate is at least partially overlapped with the orthographic projection of the Micro-LED on the substrate, and the transfer adhesive layer deforms under the action of the laser so as to remove the Micro-LED. According to the technical scheme of the embodiment, the through holes are formed in the conductive layer, so that laser not only can be irradiated to the transfer adhesive layer from the material of the conductive layer, but also can be irradiated to the transfer adhesive layer from the through holes of the conductive layer during mass transfer, and the transfer efficiency of the Micro-LED is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of Micro-LED, and particularly relates to a Micro-LED transfer substrate and device. Background Art

[0002] Micro-LED is a new display technology that uses inorganic LEDs as light-emitting pixels and employs a mass transfer technology to transfer Micro-LEDs to a substrate with a fabricated driving circuit to achieve the manufacture of large-size displays. The mass transfer technology plays a key role in the manufacture of Micro-LED displays.

[0003] In the existing mass transfer technology for Micro-LEDs, the conductive layer absorbs the irradiated laser, resulting in the transfer adhesive layer being unable to crack the gas, thereby affecting the efficiency of peeling off Micro-LEDs. How to reduce the laser absorption of the conductive layer during mass transfer and improve the transfer efficiency of Micro-LEDs has become an urgent problem to be solved. Summary of the Invention

[0004] Embodiments of the present invention provide a Micro-LED transfer substrate and device to solve the problem that the conductive layer has laser absorption during mass transfer, which in turn affects the mass transfer of Micro-LEDs.

[0005] In a first aspect, embodiments of the present invention provide a Micro-LED transfer substrate, comprising:

[0006] A substrate;

[0007] A conductive layer disposed on one side of the substrate, the conductive layer comprising at least one through hole;

[0008] A transfer adhesive layer disposed on the side of the conductive layer away from the substrate, the transfer adhesive layer being used for transferring Micro-LEDs;

[0009] A laser light source disposed on the side of the substrate away from the conductive layer, the laser light source being used for emitting laser light, and the laser light passing through the through hole and irradiating the transfer adhesive layer;

[0010] The orthographic projection of the through hole on the substrate overlaps at least partially with the orthographic projection of the Micro-LED on the substrate, and the transfer adhesive layer deforms under the action of the laser to remove the Micro-LED.

[0011] Optionally, the conductive layer comprises:

[0012] At least two signal lines, and the through hole is formed by enclosing between adjacent signal lines.

[0013] Optionally, the signal line includes a first trace and a second trace; the first trace and the second trace cross each other;

[0014] The included angle between the first trace and the second trace is greater than 0° and less than 180°.

[0015] Optionally, adjacent first traces are parallel to each other;

[0016] Adjacent second traces are parallel to each other;

[0017] Adjacent first traces are arranged at equal intervals;

[0018] Adjacent second traces are arranged at equal intervals.

[0019] Optionally, along the width direction of the Micro-LED, the orthographic projection of the Micro-LED on the substrate covers at least n signal lines; where n≥3.

[0020] Optionally, the signal line includes a first conductive layer and a second conductive layer;

[0021] The material of the first conductive layer includes ITO;

[0022] The material of the second conductive layer includes metal;

[0023] The second conductive layer is located on the side of the first conductive layer close to the substrate, and the orthographic projection of the first conductive layer on the substrate completely covers the orthographic projection of the second conductive layer on the substrate.

[0024] Optionally, the width of the second conductive layer is greater than zero and less than one-half of the width of the first conductive layer;

[0025] The thickness of the second conductive layer is less than the thickness of the first conductive layer.

[0026] Optionally, the transfer substrate further includes:

[0027] An insulating layer, disposed between the conductive layer and the transfer adhesive layer;

[0028] The material of the insulating layer includes at least one of SiN x , SiO x , TiO2 or Al2O3.

[0029] Optionally, the width range of the signal line is greater than or equal to 1μm and less than or equal to 50μm.

[0030] In a second aspect, an embodiment of the present invention further provides a Micro-LED transfer device, and the Micro-LED transfer device includes the Micro-LED transfer substrate provided in any embodiment of the present invention.

[0031] According to the technical solution provided by the embodiment of the present invention, by providing through holes in the conductive layer, during mass transfer, the laser can irradiate the transfer adhesive layer not only from the material of the conductive layer itself, but also from the through holes of the conductive layer to reach the transfer adhesive layer. It is ensured that the laser energy irradiated on the transfer adhesive layer is sufficient to cause the material of the transfer adhesive layer to crack, thereby generating gas to peel the Micro-LED from the transfer adhesive layer. The problem of laser absorption in the conductive layer during the mass transfer of Micro-LEDs is solved, and the transfer efficiency of Micro-LEDs is improved.

[0032] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 It is a schematic partial cross-sectional structure diagram of a Micro-LED transfer substrate provided by an embodiment of the present invention;

[0035] Figure 2 It is a schematic top view structure diagram of a conductive layer in a Micro-LED transfer substrate provided by an embodiment of the present invention;

[0036] Figure 3 It is a schematic partial top view structure diagram of a conductive layer in a Micro-LED transfer substrate provided by an embodiment of the present invention;

[0037] Figure 4 It is a schematic partial cross-sectional structure diagram of a signal line in a Micro-LED transfer substrate provided by an embodiment of the present invention;

[0038] Figure 5 It is a schematic partial cross-sectional structure diagram of another Micro-LED transfer substrate provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0041] Figure 1 It is a schematic partial cross-sectional structure diagram of a Micro-LED transfer substrate provided by an embodiment of the present invention. Figure 2 It is a schematic top view structure diagram of a conductive layer in a Micro-LED transfer substrate provided by an embodiment of the present invention. This transfer substrate can be arranged in a Micro-LED transfer device. Refer to Figure 1 and Figure 2 , this transfer substrate includes: a substrate 110; a conductive layer 120 arranged on one side of the substrate 110, the conductive layer 120 includes at least one through hole 100; a transfer adhesive layer 130 arranged on the side of the conductive layer 120 away from the substrate, the transfer adhesive layer 130 is used for transferring Micro-LED 150; a laser light source 140 arranged on the side of the substrate away from the conductive layer 120, the laser light source 140 is used for emitting laser, and the laser passes through the through hole 100 and irradiates the transfer adhesive layer 130; the orthographic projection of the through hole 100 on the substrate 110 and the orthographic projection of the Micro-LED 150 on the substrate 110 at least partially overlap, and the transfer adhesive layer 130 deforms under the action of the laser to remove the Micro-LED.

[0042] Specifically, the substrate 110 is a substrate for preparing Micro-LEDs, and the material of the substrate 110 can be sapphire. The conductive layer 120 is disposed on one side of the substrate 110. The conductive layer 120 can be a transparent conductive layer. On the one hand, when performing massive transfer of Micro-LEDs, the laser can pass through the conductive layer 120 and irradiate on the transfer adhesive layer 130; on the other hand, the lighting detection of the Micro-LED can be realized by applying an alternating field to the conductive layer 120. The material of the conductive layer 120 can include ITO (Indium tin oxide). The transfer adhesive layer 130 is disposed on the side of the conductive layer 120 away from the substrate. The material of the transfer adhesive layer 130 can be DRL adhesive (Dynamic Release Layer). There are a large number of Micro-LEDs to be transferred on the transfer adhesive layer 130. A through hole 100 is provided on the conductive layer 120. When performing massive transfer, the laser light source 140 emits laser light from the other side of the substrate 110, and the laser passes through the through hole 100 in the substrate 110 and the conductive layer 120 and irradiates on the transfer adhesive layer 130, so that the transfer adhesive layer 130 is cracked to generate gas, and the Micro-LEDs are peeled off from the transfer adhesive layer 130. Compared with the prior art, the technical solution of this embodiment reduces the energy absorbed by the conductive layer when the laser passes through the conductive layer 120 by providing the through hole 100, so that the laser energy irradiating on the transfer adhesive layer 130 can cause sufficient deformation of the transfer adhesive and generate gas, thereby peeling the Micro-LEDs from the transfer adhesive layer. It should be noted that Figure 2 Exemplarily, the shapes of the transfer substrate 110 and the conductive layer 120 are set to be circular.

[0043] The technical solution provided by the embodiment of the present invention, by providing a through hole in the conductive layer, when performing massive transfer, the laser can irradiate on the transfer adhesive layer not only from the material of the conductive layer itself, but also from the through hole of the conductive layer. Such a setting ensures that the laser energy irradiating on the transfer adhesive layer is relatively large, resulting in a relatively large deformation degree of the transfer adhesive layer material, more gas generated by cracking, a relatively large displacement when pushing the Micro-LEDs to peel off, and a relatively fast deformation rate of the transfer adhesive layer material, thereby improving the peeling efficiency of the Micro-LEDs on the transfer adhesive layer. The technical solution provided by this embodiment, by providing a through hole in the conductive layer, makes the laser energy irradiating on the transfer adhesive layer large enough, so that the material of the transfer adhesive layer can generate a relatively large degree of deformation in a relatively short time, and preferably solves the problem of laser absorption in the conductive layer during the massive transfer of Micro-LEDs, and improves the transfer efficiency of Micro-LEDs.

[0044] Optionally, on the basis of the above embodiment, refer toFigure 1 and Figure 2 The conductive layer includes at least two signal lines 200, and vias are formed between adjacent signal lines 200.

[0045] Specifically, the conductive layer 120 may include multiple signal lines 200, and the multiple signal lines 200 form a grid-like structure of the conductive layer 120. Among them, adjacent signal lines 200 enclose vias 100. By setting the vias 100, the transmission efficiency of the laser in the conductive layer 120 during mass transfer can be improved. During mass transfer, the laser emitted by the laser source can not only pass through the signal lines 200 and irradiate the transfer adhesive layer 130, but also irradiate the transfer adhesive layer 130 through the vias 100, thereby achieving the technical effect of reducing the laser absorption when the laser passes through the conductive layer. Such a setting ensures that the laser energy irradiated on the transfer adhesive layer 130 can support a large degree and high rate of deformation and cracking of the transfer adhesive layer 130, and improves the peeling efficiency of the Micro-LED from the transfer adhesive layer.

[0046] Optionally, Figure 3 FIG. is a partial top view structural schematic diagram of the conductive layer in a Micro-LED transfer substrate provided by an embodiment of the present invention. On the basis of the above embodiment, refer to Figure 3 The signal line 200 includes a first trace 310 and a second trace 320; the first trace 310 and the second trace 320 intersect; the included angle between the first trace 310 and the second trace 320 is greater than 0° and less than 180°.

[0047] Specifically, the first trace 310 and the second trace 320 are signal lines along two different directions. The included angle between the first trace 310 and the second trace 320 can be any angle between 0° and 180°. Exemplarily, the included angle between the first trace 310 and the second trace 320 can be 30°, 60°, 90°, 120°, etc. The first trace 310 and the second trace 320 can be straight lines, curves or other shaped line structures. In this embodiment, the line shapes of the first trace 310 and the second trace 320 and the included angle between the first trace 310 and the second trace 320 are not specifically limited.

[0048] Preferably, refer to Figure 3 The first trace 310 and the second trace 320 can be set to be straight, and the included angle between the first trace 310 and the second trace 320 can be set to 90°, thereby reducing the preparation process difficulty of the conductive layer and saving production costs.

[0049] Optionally, on the basis of the above embodiment, refer to Figure 3, two adjacent first traces 310 are parallel to each other; two adjacent second traces 320 are parallel to each other; two adjacent first traces 310 are equally spaced; two adjacent second traces 320 are equally spaced.

[0050] Specifically, when the conductive layer 120 is prepared, it needs to be lithographed into a required patterned shape. Multiple first traces 310 are parallel and equally spaced, and multiple second traces 320 are parallel and equally spaced, which can make the via hole 100 array evenly distributed on the conductive layer 120. Such a setting can, on the one hand, reduce the process difficulty during the preparation of the conductive layer; on the other hand, it can ensure that the sizes of the via holes 100 are uniform, and the via holes 100 are evenly distributed on the conductive layer 120, so that the laser can uniformly irradiate the transfer adhesive layer 130, reducing the difference in transfer rates between different regions of the entire substrate during the massive transfer of Micro-LEDs and ensuring the transfer efficiency of Micro-LEDs.

[0051] Optionally, based on the above embodiments, refer to Figure 3 , along the width direction of the Micro-LED 150, the orthographic projection of the Micro-LED 150 on the substrate covers at least n signal lines; where n≥3.

[0052] Specifically, the shape of the Micro-LED 150 can be rectangular, square or other shapes. Along the width direction of the Micro-LED, the orthographic projection of the Micro-LED 150 on the substrate covers at least 3 signal lines. Exemplarily, refer to Figure 3 , the Micro-LED 150 is rectangular, and along the direction of the second trace 320, the orthographic projection of the Micro-LED 150 on the substrate covers three first traces 310. The orthographic projection of the Micro-LED on the substrate covers multiple signal lines. On the one hand, it can ensure that the voltage received by the Micro-LED is uniform and stable when the conductive layer 120 is energized for Micro-LED lighting detection, improving the detection efficiency of the Micro-LED; on the other hand, it can ensure that there are multiple via holes 100 for the laser to pass through and irradiate the Micro-LED at the same time, thereby improving the transfer efficiency of the Micro-LED.

[0053] Optionally, Figure 4 is a schematic partial cross-sectional structure diagram of signal lines in a Micro-LED transfer substrate provided by an embodiment of the present invention. Based on the above embodiments, refer to Figure 4 , the signal line 200 includes a first conductive layer 410 and a second conductive layer 420; the material of the first conductive layer 410 includes ITO; the material of the second conductive layer 420 includes metal; the second conductive layer 420 is located on the side of the first conductive layer 410 close to the substrate 110, and the orthographic projection of the first conductive layer 410 on the substrate 100 completely covers the orthographic projection of the second conductive layer 420 on the substrate 110.

[0054] Specifically, the signal line 200 can be a two-layer structure. The second conductive layer 420 is disposed close to the substrate 110, and the first conductive layer 410 is disposed around the second conductive layer 420 in a semi-surrounding manner. The material of the first conductive layer 410 can be ITO material. The material of the second conductive layer 420 can be a metal material, such as copper, gold, aluminum or other metal materials. Doping a metal material with higher conductivity in the signal line 200 can reduce the voltage drop between the signal lines. When performing Micro-LED lighting tests on a large-area substrate, it is ensured that the voltage drop between the signal lines in the middle area and the signal lines in the edge area of the conductive layer 120 is uniform, ensuring the lighting test efficiency of the Micro-LED. It should be noted that Figure 4 An exemplary film layer structure of the first conductive layer 410 and the second conductive layer 420 in which the second trace 320 is disposed is shown.

[0055] Optionally, on the basis of the above embodiment, refer to Figure 4 , the width of the second conductive layer 420 is greater than zero and less than half of the width of the first conductive layer 410; the thickness of the second conductive layer 420 is less than the thickness of the first conductive layer 410.

[0056] Specifically, along the film layer direction of the conductive layer, the width of the second conductive layer 420 is greater than zero and less than half of the width of the first conductive layer 410, which can enable the laser to pass through the first conductive layer 410 in the signal line 200 and irradiate on the Micro-LED to be transferred during mass transfer, further ensuring the transfer efficiency. Along the thickness direction of the transfer substrate, the thickness of the second conductive layer 420 is less than the thickness of the first conductive layer 410, which can enable the first conductive layer 410 to wrap the second conductive layer 420, thereby preventing the metal material of the second conductive layer 420 from being oxidized and affecting the conductive efficiency of the conductive layer 120.

[0057] Optionally, Figure 5 This is a schematic partial cross-sectional structure diagram of another Micro-LED transfer substrate provided by an embodiment of the present invention. On the basis of the above embodiment, refer to Figure 5 , the transfer substrate further includes: an insulating layer 510, disposed between the conductive layer 120 and the transfer adhesive layer 130; the material of the insulating layer 510 includes SiN x , SiO x , TiO2 or at least one of Al2O3.

[0058] Specifically, the insulating layer 510 is disposed between the conductive layer 120 and the transfer adhesive layer 130. Since there is air between the conductive layer 120 and the corresponding detection electrode plate during the detection of Micro-LED, and the dielectric constant of air is the lowest, by providing the insulating layer 510, air breakdown can be preferably avoided, damage to the Micro-LED can be avoided, and the safety of detection can be improved. Preferably, the material of the insulating layer 510 includes SiN x , SiO x , TiO2 or at least one of Al2O3.

[0059] Optionally, the width range of the signal line 200 is greater than or equal to 1 μm and less than or equal to 50 μm.

[0060] Specifically, if the width of the signal line 200 is too narrow, the electric field strength formed by the conductive layer 120 during the lighting detection of the Micro-LED is not sufficient to drive the Micro-LED for lighting detection. If the width of the signal line 200 is too wide, the through holes of the conductive layer 120 will be too small, affecting the number of laser beams irradiated onto the Micro-LED through the through holes, and thus affecting the transfer efficiency. The width range of the signal line 200 is set to be greater than or equal to 1 μm and less than or equal to 50 μm, so that the electric field strength formed when the conductive layer is energized is sufficient to drive the Micro-LED for lighting detection, and at the same time, enough laser beams can pass through the through holes to irradiate the Micro-LED for transfer, which can better balance the detection efficiency and transfer efficiency of the Micro-LED.

[0061] The embodiment of the present invention also provides a Micro-LED transfer device. The Micro-LED transfer device provided by the embodiment of the present invention includes the Micro-LED transfer substrate provided in any of the above embodiments, and has the beneficial effects of the Micro-LED transfer substrate provided in any of the above embodiments, which will not be elaborated here.

[0062] It should be understood that the various forms of the processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0063] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A Micro-LED transfer substrate, characterized in that, Comprising: A substrate; A conductive layer disposed on one side of the substrate, the conductive layer including at least one through hole; A transfer adhesive layer disposed on the side of the conductive layer away from the substrate, the transfer adhesive layer being used for transferring Micro-LEDs; A laser light source disposed on the side of the substrate away from the conductive layer, the laser light source being used for emitting laser light, and the laser light passing through the through hole and irradiating the transfer adhesive layer; The orthographic projection of the through hole on the substrate and the orthographic projection of the Micro-LED on the substrate at least partially overlap, and the transfer adhesive layer deforms under the action of the laser to remove the Micro-LED.

2. The Micro-LED transfer substrate according to claim 1, wherein The conductive layer includes: At least two signal lines, and the through hole is formed by enclosing between adjacent signal lines.

3. The Micro-LED transfer substrate according to claim 2, wherein: The signal line includes a first trace and a second trace; the first trace and the second trace cross; The included angle between the first trace and the second trace is greater than 0° and less than 180°.

4. The Micro-LED transfer substrate according to claim 3, wherein: Adjacent two of the first traces are parallel to each other; Adjacent two of the second traces are parallel to each other; Adjacent two of the first traces are arranged at equal intervals; Adjacent two of the second traces are arranged at equal intervals.

5. The Micro-LED transfer substrate according to claim 3, wherein: Along the width direction of the Micro-LED, the orthographic projection of the Micro-LED on the substrate covers at least n signal lines; where n≥3.

6. The Micro-LED transfer substrate according to claim 1, wherein, The signal line includes a first conductive layer and a second conductive layer; The material of the first conductive layer includes ITO; The material of the second conductive layer includes a metal; The second conductive layer is located on the side of the first conductive layer close to the substrate, and the orthographic projection of the first conductive layer on the substrate completely covers the orthographic projection of the second conductive layer on the substrate.

7. The Micro-LED transfer substrate according to claim 6, wherein: The width of the second conductive layer is greater than zero and less than half of the width of the first conductive layer; The thickness of the second conductive layer is less than the thickness of the first conductive layer.

8. The Micro-LED transfer substrate according to claim 1, wherein The transfer substrate further includes: An insulating layer disposed between the conductive layer and the transfer adhesive layer; The material of the insulating layer includes at least one of SiNx, SiOx, TiO2 or Al2O3.

9. The Micro-LED transfer substrate according to claim 2, wherein The width range of the signal line is greater than or equal to 1μm and less than or equal to 50μm.

10. A Micro-LED transfer device, characterized in that, Comprising: The Micro-LED transfer substrate according to any one of claims 1 to 9.

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