Micro light emitting diode display device and manufacturing method thereof

Abstract

The invention relates to a micro light-emitting diode display device and a manufacturing method thereof, the micro light-emitting diode display device comprises a display structure and a driving backboard, the display structure comprises a first substrate and a plurality of micro light-emitting diodes, the micro light-emitting diodes are arranged on the first substrate in an array mode, and the driving backboard is arranged on the first substrate. Each micro light emitting diode comprises an epitaxial structure located on the first substrate and a transparent conductive layer located on the epitaxial structure; the driving backboard is located on the side, away from the first substrate, of the micro light-emitting diodes, the driving backboard comprises a second substrate and a plurality of driving transistors, and the driving transistors are arranged on the second substrate in an array mode; and in the direction perpendicular to the surface of the second substrate, each micro light emitting diode is aligned with one driving transistor. Accurate control between the driving transistor and the micro light-emitting diode is realized, and the resolution and transmittance of the micro light-emitting diode display device are improved.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a micro light-emitting diode display device and its manufacturing method. Background Technology

[0002] Current mainstream liquid crystal display (LCD) and organic light-emitting diode (LED) technologies suffer from limitations in brightness, high power consumption, and short lifespan. In contrast, inorganic micro-LEDs offer superior brightness (up to 10 lux). 6 With its advantages such as low power consumption (80% reduction in energy consumption) and long lifespan, it has become an ideal choice in the field of transparent displays.

[0003] In conventional micro-LED transparent display technology, a common approach is to bond horizontally structured micro-LEDs to a low-temperature polysilicon thin-film transistor (LTPS-TFT) backplane, achieving a transmittance of 60%. However, the pixel size in this approach is typically 10μm, and the opaque area in the driving circuit accounts for more than 40% of the total area. Therefore, limited by the pixel size and the proportion of opaque area in the driving circuit, the transmittance of this approach is difficult to further improve. Summary of the Invention

[0004] Therefore, it is necessary to provide a micro-light-emitting diode display device and a method for manufacturing the same, so as to simultaneously improve the transmittance and resolution of the micro-light-emitting diode display device.

[0005] This application provides a micro-light-emitting diode display device, comprising:

[0006] The display structure includes a first substrate and a plurality of micro light-emitting diodes, wherein the plurality of micro light-emitting diodes are arranged in an array on the first substrate, and each micro light-emitting diode includes an epitaxial structure located on the first substrate and a transparent conductive layer located on the epitaxial structure;

[0007] A driving backplane is located on the side of the micro light-emitting diode away from the first substrate. The driving backplane includes a second substrate and a plurality of driving transistors, and the plurality of driving transistors are arranged in an array on the second substrate.

[0008] Each of the micro-light-emitting diodes is aligned with a driving transistor along a direction perpendicular to the surface of the second substrate.

[0009] In one embodiment, the driving transistor includes:

[0010] A first dielectric layer is located on the second substrate;

[0011] Gates are arranged in an array on the first dielectric layer, and the orthogonal projection of the gates toward the second substrate at least partially coincides with the orthogonal projection of the micro-light-emitting diode toward the second substrate;

[0012] A second dielectric layer covers the first dielectric layer and the gate;

[0013] A channel region is located on the second dielectric layer, and the orthographic projection of the channel region toward the second substrate at least partially coincides with the orthographic projection of the gate toward the second substrate;

[0014] A source electrode is located on the second dielectric layer, and the source electrode covers the sidewall of one side of the channel region and at most part of the surface of the channel region;

[0015] A drain electrode is located on the second dielectric layer and covers the sidewall of the channel region away from the source electrode and at most a portion of the surface of the channel region away from the source electrode.

[0016] In one embodiment, the micro-light-emitting diodes aligned with each other are connected to the driving transistor via an electrical connector, and the two ends of the electrical connector are respectively connected to the source electrode and the transparent conductive layer.

[0017] In one embodiment, the display structure further includes:

[0018] An insulating passivation layer covers the first substrate and all of the micro light-emitting diodes;

[0019] The first encapsulation layer is located on the insulating passivation layer, and the drive backplane is located on the first encapsulation layer;

[0020] The drive backplate also includes:

[0021] The second packaging layer covers at least all of the driving transistors.

[0022] In one embodiment, the transparent conductive layer is made of at least one of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and gallium-doped zinc oxide (GZO). The first encapsulation layer and the second encapsulation layer are both made of polyimide, and the visible light transmittance of the polyimide is in the range of 90% to 100%. The second substrate is made of sapphire.

[0023] In one embodiment, the first substrate includes a first transparent conductive oxide layer, a thin film metal layer, and a second transparent conductive oxide layer stacked sequentially in a direction away from the transparent conductive layer.

[0024] Accordingly, this application also provides a method for manufacturing a micro-light-emitting diode display device, comprising:

[0025] A substrate is provided, an epitaxial structure is formed on the substrate, and a transparent conductive layer is formed on the epitaxial structure;

[0026] Remove the substrate and form a first substrate on the side of the epitaxial structure away from the transparent conductive layer;

[0027] The epitaxial structure and the transparent conductive layer are patterned to form a plurality of micro light-emitting diodes arranged in an array on the first substrate;

[0028] A driving backplane is formed on a display structure, the display structure including a first substrate and all the micro light-emitting diodes, the driving backplane including a second substrate formed on the display structure and a plurality of driving transistors formed on the second substrate, and each driving transistor is aligned with one of the micro light-emitting diodes along a direction perpendicular to the surface of the second substrate.

[0029] In one embodiment, the process of forming the epitaxial structure and the transparent conductive layer on the substrate includes:

[0030] The epitaxial structure is formed on the substrate using a chemical vapor deposition process.

[0031] The transparent conductive layer is formed on the epitaxial structure using a magnetron sputtering growth process.

[0032] The transparent conductive layer is subjected to thermal annealing.

[0033] In one embodiment, the process of removing the substrate and forming a first substrate on the side of the epitaxial structure away from the transparent conductive layer includes:

[0034] The substrate is removed by at least one of wet etching and chemical mechanical polishing processes;

[0035] The first substrate is formed on the side of the epitaxial structure away from the transparent conductive layer using electron beam evaporation and magnetron sputtering processes.

[0036] The first substrate includes a first transparent conductive oxide layer, a thin film metal layer, and a second transparent conductive oxide layer formed sequentially along a direction away from the transparent conductive layer.

[0037] In one embodiment, after patterning the epitaxial structure and the transparent conductive layer and before forming the driving backplate on the display structure, the method for manufacturing the micro-light-emitting diode display device further includes:

[0038] An insulating passivation layer is formed on the first substrate and the micro light-emitting diode using a deposition process, and the insulating passivation layer covers the sidewall of the micro light-emitting diode;

[0039] A first encapsulation layer is formed on the insulating passivation layer, and the surface of the first encapsulation layer is higher than the surface of the micro light-emitting diode;

[0040] The first encapsulation layer is planarized to make the surface of the first encapsulation layer away from the first substrate flat.

[0041] The display structure includes the first substrate, all the micro light-emitting diodes, the insulating passivation layer, and the first encapsulation layer.

[0042] In one embodiment, the process of forming the drive backplate includes:

[0043] The second substrate is formed on the first encapsulation layer;

[0044] A first dielectric layer is formed on the second substrate;

[0045] A gate material layer is formed on the first dielectric layer, and the gate material layer is patterned to form a plurality of gates arranged in an array, and the orthogonal projection of the gates toward the second substrate at least partially coincides with the orthogonal projection of the micro light-emitting diode toward the second substrate;

[0046] A second dielectric layer is formed on the first dielectric layer and the gate;

[0047] A plurality of channel regions are formed on the second dielectric layer, and the orthographic projection of the channel regions toward the second substrate at least partially coincides with the orthographic projection of the gate toward the second substrate;

[0048] The second dielectric layer, the first dielectric layer, the second substrate, the first encapsulation layer, and the insulating passivation layer are etched to form a contact hole that exposes the transparent conductive layer, and an electrical connector is formed in the contact hole;

[0049] A source electrode and a drain electrode are formed on the second dielectric layer, such that the source electrode covers the electrical connector, a sidewall on one side of the channel region, and at most a portion of the surface of the channel region, and the drain electrode covers a sidewall on the side of the channel region away from the source electrode and at most a portion of the surface of the channel region away from the source electrode, to form the driving transistor.

[0050] A second encapsulation layer is formed on the driving transistor.

[0051] An unexpected effect of this application is that by setting a driving backplate on the display structure and aligning the micro-light-emitting diodes in the display structure with the driving transistors in the driving backplate in a direction perpendicular to the surface of the second substrate, precise control between the driving transistors and the micro-light-emitting diodes is achieved, thereby improving the resolution of the micro-light-emitting diode display device; by setting a transparent conductive layer in the display structure, the transmittance of the micro-light-emitting diode display device is effectively improved. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram of the structure of a micro-light-emitting diode display device provided in one embodiment of this application.

[0054] Figure 2 A flowchart illustrating a method for manufacturing a micro-light-emitting diode display device according to one embodiment of this application.

[0055] Figure 3 This is a schematic diagram of the structure corresponding to the step of forming an epitaxial structure and a transparent conductive layer on a substrate in the manufacturing method of a micro light-emitting diode display device provided in one embodiment of this application.

[0056] Figure 4 This is a schematic diagram of the structure corresponding to the step of removing the substrate and forming a first substrate in the manufacturing method of a micro light-emitting diode display device provided in one embodiment of this application.

[0057] Figure 5 This is a schematic diagram of the structure corresponding to the step of forming an insulating passivation layer and a first encapsulation layer on a micro-light-emitting diode in the manufacturing method of a micro-light-emitting diode display device provided in one embodiment of this application.

[0058] Figure 6 This is a schematic diagram of the structure corresponding to the step of forming a second substrate, a first dielectric layer, a gate, a second dielectric layer, and a channel region on the display structure in a method for manufacturing a micro-light-emitting diode display device according to one embodiment of this application.

[0059] Figure 7This is a schematic diagram of the structure corresponding to the step of forming an electrical connector in the manufacturing method of a micro light-emitting diode display device provided in one embodiment of this application.

[0060] Figure 8 This is a schematic diagram of the structure corresponding to the steps of forming the source electrode, the drain electrode, and the second encapsulation layer in the manufacturing method of the micro light-emitting diode display device provided in one embodiment of this application.

[0061] The reference numerals in the figures include: 100-first substrate; 101-substrate; 110-epitaxy structure; 111-n-type gallium nitride layer; 112-quantum well composite layer; 113-p-type gallium nitride layer; 120-transparent conductive layer; 121-insulating passivation layer; 122-first encapsulation layer; 130-second substrate; 131-first dielectric layer; 140-gate; 141-second dielectric layer; 150-channel region; 151-source electrode; 152-drain electrode; 160-second encapsulation layer; A-display structure; a-micro light-emitting diode; B-driving backplane; b-driving transistor; c-electrical connector. Detailed Implementation

[0062] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate 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 so that the disclosure of this application will be thorough and complete.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0064] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, parts, regions, layers, doping types, and / or portions, these elements, parts, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, part, region, layer, doping type, or portion from another element, part, region, layer, doping type, or portion. Therefore, without departing from the teachings of this application, the first element, component, region, layer, doping type, or portion discussed below may be represented as a second element, component, region, layer, or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0065] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0066] When used herein, the singular forms of “a,” “an,” and “ / the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, in this specification, the term “and / or” includes any and all combinations of the associated listed items.

[0067] In the current display technology field, micro-LEDs have become an ideal choice for transparent displays due to their advantages of high brightness, low power consumption, and long lifespan. However, the industrialization of micro-LED transparent display technology still faces many challenges. The first challenge is the insufficient mass transfer yield for micrometer-level pixels below 5μm (e.g., typical mass transfer yields are usually less than 70%). The second challenge is the insufficient heterogeneous integration precision between the thin-film transistor (TFT) driving backplane and the micro-LED array; the alignment error between them can exceed 1μm in some cases. The third challenge is the excessively high interfacial contact resistance between the transparent conductive material and the gallium nitride epitaxial layer; the interfacial contact resistivity can exceed 10⁻⁶. -3 Ω·cm 2 .

[0068] To address these challenges, a common approach is to bond horizontally structured micro-light-emitting diodes to a low-temperature polycrystalline silicon thin-film transistor backplane to improve transmittance. However, this approach is limited by pixel size and the proportion of opaque areas in the driving circuit, making it difficult to further improve transmittance.

[0069] Based on this, this application provides a micro-light-emitting diode display device and a method for manufacturing the same, so as to simultaneously improve the transmittance and resolution of the micro-light-emitting diode display device.

[0070] Figure 1 This is a schematic diagram of the structure of a micro-light-emitting diode display device provided in one embodiment of this application. (See also...) Figure 1 One embodiment of this application provides a micro-light-emitting diode display device including a display structure A and a driving backplate B. The display structure A includes a first substrate 100 and a plurality of micro-light-emitting diodes a. The plurality of micro-light-emitting diodes a are arranged in an array on the first substrate 100, and each micro-light-emitting diode a includes an epitaxial structure 110 located on the first substrate 100 and a transparent conductive layer 120 located on the epitaxial structure 110. The driving backplate B is located on the side of the micro-light-emitting diodes a away from the first substrate 100. The driving backplate B includes a second substrate 130 and a plurality of driving transistors b. The plurality of driving transistors b are arranged in an array on the second substrate 130. In the direction perpendicular to the surface of the second substrate 130 (i.e., the X direction), each micro-light-emitting diode a is aligned with a driving transistor b.

[0071] As described above, the micro-light-emitting diode display device achieves precise control between the driving transistor and the micro-light-emitting diode by setting a driving backplate on the display structure and aligning the micro-light-emitting diodes in the display structure with the driving transistors in the driving backplate in a direction perpendicular to the surface of the second substrate, thereby improving the resolution of the micro-light-emitting diode display device; and by setting a transparent conductive layer in the display structure, the transmittance of the micro-light-emitting diode display device is effectively improved.

[0072] In one embodiment, the first substrate includes a first transparent conductive oxide layer, a thin-film metal layer, and a second transparent conductive oxide layer (not shown in the figure) stacked sequentially in a direction away from the micro-light-emitting diode, and the thickness of the first substrate is approximately 100 nm. Optionally, the first substrate includes a stacked structure composed of indium tin oxide (ITO), metallic silver (Ag), and indium tin oxide (ITO). In this case, metallic silver can be replaced with metallic gold (Au) or other commonly used thin-film metal materials, and indium tin oxide can be replaced with aluminum-doped zinc oxide (AZO) or other commonly used transparent conductive oxide materials. This application does not impose any limitations on this. It should be noted that when setting the thickness of the first substrate and selecting the material of the first substrate, the influence of thickness and material on the light transmittance of the first substrate needs to be considered to maximize the transmittance of the first substrate, thereby helping to improve the transmittance of the micro-light-emitting diode display device.

[0073] Continue reading Figure 1 In one embodiment, the epitaxial structure 110 includes an n-type gallium nitride layer 111, a quantum well composite layer 112, and a p-type gallium nitride layer 113 stacked sequentially from bottom to top. The n-type gallium nitride layer 111 is located on a first substrate 100, and the transparent conductive layer 120 is located on the p-type gallium nitride layer 113. The n-type gallium nitride layer 111 is a silicon (Si) doped layer in gallium nitride, and the p-type gallium nitride layer 113 is a magnesium (Mg) doped layer in gallium nitride (GaN). Optionally, the thickness of the n-type gallium nitride layer 111 may be, for example, 2.8 μm, and the combined thickness of the quantum well composite layer 112 and the p-type gallium nitride layer 113 may be, for example, 0.8 μm. In other embodiments of this application, the specific structure, material, and thickness of the epitaxial structure 110 can be adjusted according to actual needs, and this application does not impose any limitations on this.

[0074] In one embodiment, the material of the transparent conductive layer includes at least one of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and gallium-doped zinc oxide (GZO). In other embodiments of this application, the material of the transparent conductive layer can be adjusted to other conductive materials as needed. For example, the material of the transparent conductive layer can be a transparent oxide material or a thin film metal material, as long as the transmittance of the transparent conductive layer is greater than or equal to 90%.

[0075] Continue reading Figure 1 In one embodiment, the display structure A further includes an insulating passivation layer 121 and a first encapsulation layer 122, wherein the insulating passivation layer 121 covers the first substrate 100 and all micro light-emitting diodes a, the first encapsulation layer 122 is located on the insulating passivation layer 121, and the driving backplate B is located on the first encapsulation layer 122.

[0076] In one embodiment, the insulating passivation layer includes a passivation layer covering the first substrate and all micro-light-emitting diodes (LEDs) and an insulating layer located on the passivation layer. Optionally, the material of the passivation layer includes aluminum oxide, and the material of the insulating layer includes silicon oxide. It should be noted that in other embodiments of this application, the specific structure of the insulating passivation layer, the thickness of each film layer, and the materials used can be set according to actual needs. It is only necessary to ensure that the insulating passivation layer meets the conditions of "having insulation properties," "being able to protect the first substrate and micro-light-emitting diodes from corrosion damage," and "the transmittance of the insulating passivation layer is between 90% and 95%" to improve the transmittance of the micro-light-emitting diode display device while ensuring its normal operation.

[0077] In one embodiment, the material of the first encapsulation layer includes polyimide (PI), and the visible light transmittance of the polyimide material ranges from 90% to 100% (i.e., the visible light transmittance range is greater than or equal to 90%), to improve the transmittance of the micro-LED display device. In other embodiments of this application, the material of the first encapsulation layer can also be replaced with other light-transmitting materials as needed, and this application does not limit this. Optionally, the thickness of the first encapsulation layer is greater than the height of the micro-LED (i.e., the height of the micro-LED in the direction perpendicular to the surface of the first substrate), and the surface of the first encapsulation layer away from the first substrate is flat, so that a driving backplate can be disposed on the surface of the first encapsulation layer away from the first substrate.

[0078] Continue reading Figure 1In one embodiment, the driving transistor b includes a first dielectric layer 131, a gate 140, a second dielectric layer 141, a channel region 150, a source electrode 151, and a drain electrode 152; wherein the first dielectric layer 131 is located on a second substrate 130, the gates 140 are arranged in an array on the first dielectric layer 131, and the orthographic projection of the gates 140 toward the second substrate 130 at least partially overlaps with the orthographic projection of the micro-light-emitting diode a toward the second substrate 130; the second dielectric layer 141 covers the first dielectric layer 131 and the gates 140, and the channel region 150... Located on the second dielectric layer 141, the orthogonal projection of the channel region 150 toward the second substrate 130 at least partially coincides with the orthogonal projection of the gate 140 toward the second substrate 130. The source electrode 151 is located on the second dielectric layer 141 and covers the sidewall of the channel region 150 on one side and at most a portion of the surface of the channel region 150. The drain electrode 152 is located on the second dielectric layer 141 and covers the sidewall of the channel region 150 away from the source electrode 151 and at most a portion of the surface of the channel region 150 away from the source electrode 151.

[0079] In one embodiment, the second substrate is made of sapphire, the first and second dielectric layers are both made of aluminum oxide (Al2O3), the gate is made of a metallic material, the channel region is made of molybdenum disulfide (MoS2), and the source and drain electrodes are both made of conductive materials. In other embodiments of this application, the materials and thicknesses of each film layer in the driving transistor can be adjusted according to actual needs. It should be emphasized that since the materials and thicknesses of each film layer in the driving transistor affect its transmittance, when setting the relevant parameters of each film layer, materials with higher transmittance can be prioritized while ensuring the normal operation of the driving transistor. Simultaneously, the thickness of each film layer can be reduced as much as possible to improve the transmittance of the driving transistor, thereby helping to improve the transmittance of the micro-LED display device.

[0080] Continue reading Figure 1 In one embodiment, the driving backplane B further includes a second encapsulation layer 160, and the second encapsulation layer 160 at least covers the driving transistor b. Optionally, the material of the second encapsulation layer 160 includes polyimide. In other embodiments of this application, the material of the second encapsulation layer can also be replaced with other light-transmitting materials as needed, and this application does not limit this. Optionally, the thickness of the second encapsulation layer 160 is greater than the height of the source electrode 151 and the drain electrode 152, and the surface of the second encapsulation layer 160 away from the driving transistor b is flat to improve the encapsulation effect of the driving backplane B.

[0081] See Figure 1In one embodiment, the aligned micro-light-emitting diodes a and the driving transistor b are connected by an electrical connector c, with both ends of the connector c connected to the source electrode 151 and the transparent conductive layer 120, respectively. Optionally, the material of the electrical connector c includes a conductive material.

[0082] It should be noted that the display structure of the micro-LED display device described above includes a micro-LED array with high brightness (meganits), high yield (90%) and ultra-small size (1.5μm). The driving backplate has high transmittance, and the driving transistors arranged in the array realize one-to-one precise control of the micro-LEDs, so that the micro-LED display is achieving both ultra-high resolution and high transmittance.

[0083] Accordingly, see Figure 2 One embodiment of this application also provides a method for manufacturing a micro light-emitting diode display device, including the following steps S01 to S04.

[0084] Step S01: Provide a substrate, form an epitaxial structure on the substrate, and form a transparent conductive layer on the epitaxial structure.

[0085] It should be noted that by forming a transparent conductive layer, the transmittance of the display structure can be improved while ensuring the normal functioning of the display structure.

[0086] Step S02: Remove the substrate and form a first substrate on the side of the epitaxial structure away from the transparent conductive layer.

[0087] It should be noted that by controlling the thickness and material of the first substrate, the transmittance of the first substrate can be improved, thereby further enhancing the transmittance of the display structure.

[0088] Step S03: The epitaxial structure and the transparent conductive layer are patterned to form a plurality of micro light-emitting diodes arranged in an array on the first substrate.

[0089] Step S04: Form a driving backplane on the display structure, the display structure including the first substrate and all the micro light-emitting diodes, the driving backplane including a second substrate formed on the display structure and a plurality of driving transistors formed on the second substrate, and each driving transistor is aligned with one of the micro light-emitting diodes along a direction perpendicular to the surface of the second substrate.

[0090] The manufacturing method of the micro-light-emitting diode display device described above improves the transmittance of the display structure by forming a display structure with an array of micro-light-emitting diodes and a transparent conductive layer formed inside the micro-light-emitting diodes, thereby effectively improving the transmittance of the micro-light-emitting diode display device. By forming a driving backplate on the display structure and aligning the micro-light-emitting diodes in the display structure with the driving transistors in the driving backplate in a direction perpendicular to the surface of the second substrate, precise control between the driving transistors and the micro-light-emitting diodes is achieved, thereby improving the resolution of the micro-light-emitting diode display device.

[0091] See Figure 3 In one embodiment, the process of forming the epitaxial structure 110 and the transparent conductive layer 120 on the substrate 101 includes: forming the epitaxial structure 110 on the substrate 101 using a chemical vapor deposition process; forming the transparent conductive layer 120 on the epitaxial structure 110 using a magnetron sputtering growth process; and performing rapid thermal annealing (RTA) on the transparent conductive layer 120 to promote grain growth within the transparent conductive layer 120, increase grain boundary density, eliminate defects, and improve the conductivity and light transmittance of the transparent conductive layer 120. Optionally, the thickness of the substrate 101 is, for example, 1000 μm.

[0092] In one embodiment, the epitaxial structure 110 is formed using a metal-organic chemical vapor deposition (MOCVD) process. Optionally, the epitaxial structure 110 includes an n-type gallium nitride layer 111, a quantum well composite layer 112, and a p-type gallium nitride layer 113 formed on a substrate 101.

[0093] See Figure 4 In one embodiment, the process of removing the substrate 101 and forming a first substrate 100 on the side of the epitaxial structure 110 away from the transparent conductive layer 120 includes: removing the substrate 101 using at least one of wet etching and chemical mechanical polishing; forming the first substrate 100 on the side of the epitaxial structure 110 away from the transparent conductive layer 120 using electron beam evaporation and magnetron sputtering; wherein the first substrate 100 includes a first transparent conductive oxide layer, a thin film metal layer, and a second transparent conductive oxide layer (not shown in the figure) sequentially formed along a direction away from the transparent conductive layer 120. It should be emphasized that during the fabrication of the first substrate 100, the transmittance of the first substrate 100 can be improved by adjusting the thickness of the first substrate 100.

[0094] Then refer to Figure 4 and Figure 5In one embodiment, the process of patterning the epitaxial structure 110 and the transparent conductive layer 120 to form a plurality of micro light-emitting diodes a arranged in an array on the first substrate 100 includes: forming a patterned photoresist layer (not shown) on the transparent conductive layer 120; etching the transparent conductive layer 120 and the epitaxial structure 110 using an inductively coupled plasma etching process to form a plurality of micro light-emitting diodes a arranged in an array; and removing the patterned photoresist layer and the polymer generated in the inductively coupled plasma etching process using an ashing process and a wet cleaning process.

[0095] Continue reading Figure 5 In one embodiment, after patterning the epitaxial structure 110 and the transparent conductive layer 120, and before forming a driving backplate on the display structure, the manufacturing method of the micro-light-emitting diode display device further includes: forming an insulating passivation layer 121 on a first substrate 100 and micro-light-emitting diodes a using a deposition process, wherein the insulating passivation layer 121 covers the sidewalls of the micro-light-emitting diodes a; forming a first encapsulation layer 122 on the insulating passivation layer 121, wherein the surface of the first encapsulation layer 122 is higher than the surface of the micro-light-emitting diodes a; and performing planarization processing on the first encapsulation layer 122 to make the surface of the first encapsulation layer 122 away from the first substrate 100 flat; wherein the display structure A includes a first substrate 100, all micro-light-emitting diodes a, an insulating passivation layer 121, and a first encapsulation layer 122.

[0096] In one embodiment, the insulating passivation layer comprises a stacked structure of an aluminum oxide layer and a silicon oxide layer, and the fabrication process of the insulating passivation layer includes: depositing an aluminum oxide layer using atomic layer deposition (ALD) technology, and forming a silicon oxide layer on the aluminum oxide layer using plasma enhanced chemical vapor deposition (PECVD) technology, to repair etching damage to the sidewalls of the micro-light-emitting diode and protect the first substrate and the micro-light-emitting diode from damage and contamination in subsequent process steps. Optionally, the thickness of the aluminum oxide layer is, for example, 50 nm, and the thickness of the silicon oxide layer is, for example, 200 nm.

[0097] In one embodiment, the material of the first encapsulation layer includes polyimide to improve the transmittance of the display structure. Optionally, the first encapsulation layer is planarized using a chemical mechanical polishing (CMP) process to flatten the surface of the first encapsulation layer away from the first substrate, so that a drive backplate can be subsequently formed on the surface of the first encapsulation layer away from the first substrate.

[0098] Then refer to Figures 6 to 8 In one embodiment, the driving backplane B is fabricated using in-situ integration technology, so that the driving transistor b in the driving backplane B is connected one-to-one with the micro light-emitting diode a in the display structure A, thereby realizing independent addressing and driving of the micro light-emitting diode.

[0099] For example, the specific process of fabricating the drive backplane using in-situ integration technology includes: (See...) Figure 6 A second substrate 130 is formed on the first encapsulation layer 122; a first dielectric layer 131 is formed on the second substrate 130; a gate material layer (not shown in the figure) is formed on the first dielectric layer 131, and the gate material layer is patterned to form a plurality of gates 140 arranged in an array, such that the orthographic projection of the gate 140 toward the second substrate 130 at least partially coincides with the orthographic projection of the micro-light-emitting diode a toward the second substrate 130; a second dielectric layer 141 is formed on the first dielectric layer 131 and the gates 140; a plurality of channel regions 150 are formed on the second dielectric layer 141, such that the orthographic projection of the channel regions 150 toward the second substrate 130 at least partially coincides with the orthographic projection of the gates 140 toward the second substrate 130; see reference. Figure 7 The second dielectric layer 141, the first dielectric layer 131, the second substrate 130, the first encapsulation layer 122, and the insulating passivation layer 121 are etched to form contact holes (not shown in the figure) exposing the transparent conductive layer 120, and electrical connectors c are formed within the contact holes; see reference Figure 8 A source electrode 151 and a drain electrode 152 are formed on the second dielectric layer 141, such that the source electrode 151 covers the electrical connector c, the sidewall on one side of the channel region 150 and at most a portion of the surface of the channel region 150, and the drain electrode 152 covers the sidewall on the side of the channel region 150 away from the source electrode 151 and at most a portion of the surface of the channel region 150 away from the source electrode 151, to form a driving transistor b; a second encapsulation layer 160 is formed on the driving transistor b.

[0100] In one embodiment, the second substrate can be made of sapphire to improve the transmittance of the drive backplane. Optionally, an atomic layer deposition technique is used to form the first dielectric layer and the second dielectric layer, and both the first dielectric layer and the second dielectric layer are made of oxide materials, such as aluminum oxide.

[0101] In one embodiment, an electron beam evaporation process is used to form a gate material layer, and an inductively coupled plasma etching process is used to etch the gate material layer to form the gate. Optionally, the gate material includes a metallic material.

[0102] In one embodiment, the channel region material can be grown using chemical vapor deposition and transferred to the second dielectric layer via gold film transfer to form the channel region. Optionally, the channel region material may be, for example, molybdenum disulfide (MoS2).

[0103] In one embodiment, an inductively coupled plasma etching process is used to etch downwards from the second dielectric layer until the transparent conductive layer is exposed, and an electron beam evaporation technique is used to deposit metal in the contact holes formed by the etching to form an electrical connector connecting the micro light-emitting diode and the driving transistor.

[0104] In one embodiment, an electrode material layer is formed on the second dielectric layer, the electrical connector and the channel region using a thermal evaporation process, and the electrode material layer is patterned to form the source electrode and the drain electrode, respectively.

[0105] In one embodiment, a second encapsulation layer is formed on the driving transistor using a deposition process, and the second encapsulation layer is planarized to make the surface of the second encapsulation layer away from the driving transistor flat, thereby improving the encapsulation effect of the driving backplane. Optionally, the material of the second encapsulation layer includes polyimide.

[0106] It should be noted that the materials and manufacturing processes of each film layer and structure in the drive backplane can be adjusted according to actual needs. Those skilled in the art can adjust the specific manufacturing method and related parameters of the drive backplane based on their professional knowledge and common sense. This application does not impose any restrictions on this.

[0107] An unexpected effect of this application is that by setting a driving backplate on the display structure and aligning the micro-light-emitting diodes in the display structure with the driving transistors in the driving backplate in a direction perpendicular to the surface of the second substrate, precise control between the driving transistors and the micro-light-emitting diodes is achieved, thereby improving the resolution of the micro-light-emitting diode display device; by setting a transparent conductive layer in the display structure, the transmittance of the micro-light-emitting diode display device is effectively improved.

[0108] In the description of this specification, the references to terms such as "some embodiments," "other embodiments," "ideal embodiments," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0109] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A micro-light-emitting diode display device, characterized in that, include: The display structure includes a first substrate and a plurality of micro light-emitting diodes, wherein the plurality of micro light-emitting diodes are arranged in an array on the first substrate, and each micro light-emitting diode includes an epitaxial structure located on the first substrate and a transparent conductive layer located on the epitaxial structure; A driving backplane is located on the side of the micro light-emitting diode away from the first substrate. The driving backplane includes a second substrate and a plurality of driving transistors, and the plurality of driving transistors are arranged in an array on the second substrate. Each of the micro-light-emitting diodes is aligned with a driving transistor along a direction perpendicular to the surface of the second substrate.

2. The micro-light-emitting diode display device according to claim 1, characterized in that, The driving transistor includes: A first dielectric layer is located on the second substrate; Gates are arranged in an array on the first dielectric layer, and the orthogonal projection of the gates toward the second substrate at least partially coincides with the orthogonal projection of the micro-light-emitting diode toward the second substrate; A second dielectric layer covers the first dielectric layer and the gate; A channel region is located on the second dielectric layer, and the orthographic projection of the channel region toward the second substrate at least partially coincides with the orthographic projection of the gate toward the second substrate; A source electrode is located on the second dielectric layer, and the source electrode covers the sidewall of one side of the channel region and at most part of the surface of the channel region; A drain electrode is located on the second dielectric layer and covers the sidewall of the channel region away from the source electrode and at most a portion of the surface of the channel region away from the source electrode.

3. The micro-light-emitting diode display device according to claim 2, characterized in that, The micro-light-emitting diodes aligned with each other are connected to the driving transistor via an electrical connector, and the two ends of the electrical connector are respectively connected to the source electrode and the transparent conductive layer.

4. The micro-light-emitting diode display device according to claim 1 or 2, characterized in that, The display structure further includes: An insulating passivation layer covers the first substrate and all of the micro light-emitting diodes; The first encapsulation layer is located on the insulating passivation layer, and the drive backplane is located on the first encapsulation layer; The drive backplate also includes: The second packaging layer covers at least all of the driving transistors.

5. The micro-light-emitting diode display device according to claim 4, characterized in that, The transparent conductive layer is made of at least one of indium tin oxide, aluminum-doped zinc oxide, and gallium-doped zinc oxide. Both the first and second encapsulation layers are made of polyimide, and the visible light transmittance of the polyimide is in the range of 90% to 100%. The second substrate is made of sapphire.

6. The micro-light-emitting diode display device according to claim 1, characterized in that, The first substrate includes a first transparent conductive oxide layer, a thin film metal layer, and a second transparent conductive oxide layer stacked sequentially in a direction away from the transparent conductive layer.

7. A method for manufacturing a micro-light-emitting diode display device, characterized in that, include: A substrate is provided, an epitaxial structure is formed on the substrate, and a transparent conductive layer is formed on the epitaxial structure; Remove the substrate and form a first substrate on the side of the epitaxial structure away from the transparent conductive layer; The epitaxial structure and the transparent conductive layer are patterned to form a plurality of micro light-emitting diodes arranged in an array on the first substrate; A driving backplane is formed on a display structure, the display structure including a first substrate and all the micro light-emitting diodes, the driving backplane including a second substrate formed on the display structure and a plurality of driving transistors formed on the second substrate, and each driving transistor is aligned with one of the micro light-emitting diodes along a direction perpendicular to the surface of the second substrate.

8. The method for manufacturing a micro-light-emitting diode display device according to claim 7, characterized in that, The process of forming the epitaxial structure and the transparent conductive layer on the substrate includes: The epitaxial structure is formed on the substrate using a chemical vapor deposition process. The transparent conductive layer is formed on the epitaxial structure using a magnetron sputtering growth process. The transparent conductive layer is subjected to thermal annealing.

9. The method for manufacturing a micro-light-emitting diode display device according to claim 7, characterized in that, The process of removing the substrate and forming a first substrate on the side of the epitaxial structure away from the transparent conductive layer includes: The substrate is removed by at least one of wet etching and chemical mechanical polishing processes; The first substrate is formed on the side of the epitaxial structure away from the transparent conductive layer using electron beam evaporation and magnetron sputtering processes. The first substrate includes a first transparent conductive oxide layer, a thin film metal layer, and a second transparent conductive oxide layer formed sequentially along a direction away from the transparent conductive layer.

10. The method for manufacturing a micro-light-emitting diode display device according to claim 7, characterized in that, After patterning the epitaxial structure and the transparent conductive layer, and before forming the driving backplate on the display structure, the manufacturing method of the micro-light-emitting diode display device further includes: An insulating passivation layer is formed on the first substrate and the micro light-emitting diode using a deposition process, and the insulating passivation layer covers the sidewall of the micro light-emitting diode; A first encapsulation layer is formed on the insulating passivation layer, and the surface of the first encapsulation layer is higher than the surface of the micro light-emitting diode; The first encapsulation layer is planarized to make the surface of the first encapsulation layer away from the first substrate flat. The display structure includes the first substrate, all the micro light-emitting diodes, the insulating passivation layer, and the first encapsulation layer.

11. The method for manufacturing a micro-light-emitting diode display device according to claim 10, characterized in that, The process of forming the drive backplate includes: The second substrate is formed on the first encapsulation layer; A first dielectric layer is formed on the second substrate; A gate material layer is formed on the first dielectric layer, and the gate material layer is patterned to form a plurality of gates arranged in an array, and the orthogonal projection of the gates toward the second substrate at least partially coincides with the orthogonal projection of the micro light-emitting diode toward the second substrate; A second dielectric layer is formed on the first dielectric layer and the gate; A plurality of channel regions are formed on the second dielectric layer, and the orthographic projection of the channel regions toward the second substrate at least partially coincides with the orthographic projection of the gate toward the second substrate; The second dielectric layer, the first dielectric layer, the second substrate, the first encapsulation layer, and the insulating passivation layer are etched to form a contact hole that exposes the transparent conductive layer, and an electrical connector is formed in the contact hole; A source electrode and a drain electrode are formed on the second dielectric layer, such that the source electrode covers the electrical connector, a sidewall on one side of the channel region, and at most a portion of the surface of the channel region, and the drain electrode covers a sidewall on the side of the channel region away from the source electrode and at most a portion of the surface of the channel region away from the source electrode, to form the driving transistor. A second encapsulation layer is formed on the driving transistor.

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