Micro light-emitting diode display and preparation method therefor

Abstract

The present application relates to the technical field of semiconductor devices. Disclosed are a micro light-emitting diode display and a preparation method therefor. The micro light-emitting diode display comprises a substrate and a first LED unit layer. The substrate comprises a plurality of first contacts. The first LED unit layer is bonded to the substrate, and comprises a first passivation layer and a plurality of first LED units, wherein the first passivation layer is located on the surface of the side of the first LED unit layer that faces away from the substrate, and exposes the surfaces of the sides of the plurality of first LED units that face away from the substrate; and the first passivation layer further covers side faces of the plurality of first LED units. The first LED unit layer further comprises a planarization layer and first electrically conductive bumps, wherein the planarization layer is bonded to the substrate; and one end of each first electrically conductive bump is electrically connected to a first LED unit, and the other end thereof is bonded and electrically connected to a corresponding first contact. In the present application, the passivation layer is used as a machining position reference, such that the LED units are protected and bonded, thereby reducing the machining difficulty and cost, and improving the yield.

Description

Miniature LED Display and its Fabrication Method

[0001] This application claims priority to Chinese patent application filed on March 27, 2025, with application number 202510369135.3, entitled "Miniature Light Emitting Diode Display and Method for Fabrication Thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of semiconductor device technology, specifically relating to a micro light-emitting diode display and its fabrication method. Background Technology

[0003] The application scenarios of display technology based on semiconductor devices are becoming increasingly diverse, such as wearable devices and virtual reality (VR) / augmented reality (AR) devices. However, the relatively large size of micro-LED displays limits the number of pixels that can be integrated into the displays of small wearable devices such as AR glasses, affecting the resolution and display effect of the devices.

[0004] In related technologies, a microdisplay module and its fabrication method are disclosed (CN119546027A). The microdisplay module includes at least two stacked pixel layers bonded to the same side of a driving substrate. Specifically, the first pixel layer is bonded to the driving substrate via a first wiring layer, and the first pixel layer and the second pixel layer are bonded via a second wiring layer and a third wiring layer. The complex structure of the microdisplay module in the related technology results in a relatively large size and difficult fabrication process, leading to increased costs and reduced overall yield.

[0005] Application content

[0006] This application aims to address at least one of the technical problems existing in the related art.

[0007] Therefore, the first aspect of this application provides a miniature light-emitting diode display.

[0008] A second aspect of this application provides a method for fabricating a miniature light-emitting diode display.

[0009] According to a first aspect of the embodiments of this application, a micro light-emitting diode display is provided, including a substrate, the substrate including a plurality of first contacts; a first LED unit layer bonded to the substrate, the first LED unit layer including a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on the surface of the first LED unit layer facing away from the substrate and exposes the surface of the plurality of first LED units facing away from the substrate; and the first passivation layer also covers at least the side surfaces of the plurality of first LED units; the first LED unit layer further includes a planarization layer and a first conductive protrusion, the planarization layer is disposed on the side of the first passivation layer facing the substrate and bonded to the substrate; one end of the first conductive protrusion is electrically connected to the first LED unit, and the other end is electrically connected to the corresponding first contact bond; the plurality of first LED units are respectively electrically connected to the substrate to achieve individual driving.

[0010] In one possible implementation of the first aspect, the micro LED display further includes a second LED unit layer bonded to the first LED unit layer. The second LED unit layer includes a plurality of second LED units arranged at intervals and a filler layer located between adjacent second LED units. The filler layer is bonded to the first passivation layer. The plurality of second LED units are electrically connected to the substrate to achieve individual driving.

[0011] In one possible implementation of the first aspect, the first LED unit layer further includes: a first electrode layer disposed on the side of the first passivation layer away from the first LED unit, and surrounding the side of the first LED unit and the side facing the substrate; and the first electrode layer covers the surface of the first LED unit on the side facing the substrate and not covered by the first passivation layer, and the first electrode layer reflects the light emitted by the first LED unit.

[0012] In one possible implementation of the first aspect, the second LED unit layer further includes: a second passivation layer disposed on the surface of the leveling layer opposite to the substrate, and exposing the surfaces of the plurality of second LED units opposite to the substrate; and the second passivation layer also covers at least the sides of the plurality of second LED units.

[0013] In one possible implementation of the first aspect, the second LED unit layer further includes: a second electrode layer disposed on the side of the second passivation layer away from the second LED unit, and surrounding the side of the second LED unit and the side facing the substrate; and the second electrode layer covers the surface of the second LED unit on the side facing the substrate that is not covered by the second passivation layer, and the second electrode layer reflects the light emitted by the second LED unit.

[0014] In one possible implementation of the first aspect, the micro LED display further includes: a conductive post extending vertically through the first LED unit layer, one end of the conductive post being electrically connected to the substrate, and the other end of the conductive post being electrically connected to the corresponding second LED unit.

[0015] In one possible implementation of the first aspect, the second LED unit layer further includes: a second conductive protrusion, the second conductive protrusion being electrically connected to the second LED unit; wherein the conductive post is electrically connected to the second LED unit through the second conductive protrusion.

[0016] In one possible implementation of the first aspect, the first LED unit and the second LED unit respectively include a first doped semiconductor layer, an active layer and a second doped semiconductor layer stacked together, the first doped semiconductor layer being close to the substrate; the surface of the second doped semiconductor layer of the first LED unit facing away from the substrate is flush with the surface of the first passivation layer facing away from the substrate; the surface of the second doped semiconductor layer of the second LED unit facing away from the substrate is flush with the surface of the second passivation layer facing away from the substrate.

[0017] In one possible implementation of the first aspect, the substrate includes at least one second contact, and the micro LED display further includes a common electrode layer electrically connected to the surface of the first LED unit and the second LED unit opposite to the substrate, and the common electrode layer is also electrically connected to the second contact.

[0018] In one possible implementation of the first aspect, the micro LED display further includes: a plurality of color conversion units, spaced apart on the side of the second LED unit layer away from the substrate, and located on a portion of the first LED unit or a portion of the second LED unit, wherein the color conversion units are used to convert a first color light emitted by the first LED unit or a second color light emitted by the second LED unit into a third color light, wherein the first color light, the second color light and the third color light are different; wherein at least one first LED unit, at least one adjacent second LED unit and at least one adjacent color conversion unit constitute a full-color pixel.

[0019] In one possible implementation of the first aspect, the micro LED display further includes: a third LED unit layer bonded to the second LED unit layer, comprising a plurality of third LED units spaced apart, wherein the vertical projections of the first LED unit, the second LED unit, and the third LED unit on the substrate do not overlap; wherein at least one first LED unit, together with at least one adjacent second LED unit and at least one adjacent third LED unit, constitute a full-color pixel.

[0020] According to a second aspect of the embodiments of this application, a method for fabricating a micro light-emitting diode display is provided, comprising the following steps:

[0021] A substrate is provided, the substrate including a plurality of first contacts;

[0022] A first LED unit layer is fabricated, the first LED unit layer including a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on the surface of the first LED unit layer facing away from the substrate, and exposes the surface of the plurality of first LED units facing away from the substrate; and the first passivation layer also covers at least the side surfaces of the plurality of first LED units; the first LED unit layer further includes a planarization layer and a first conductive protrusion, the planarization layer being disposed on the side of the first passivation layer facing the substrate; the first conductive protrusion being disposed on the planarization layer, one end of the first conductive protrusion being electrically connected to the first LED unit;

[0023] The first LED unit layer is bonded to the substrate, wherein the planarization layer is bonded to the substrate, and the first conductive protrusion is electrically connected to the corresponding first contact bond.

[0024] In this embodiment, multiple first LED units are electrically connected to the substrate to achieve individual driving.

[0025] In one possible implementation of the second aspect, after the step of bonding the first LED unit layer to the substrate, the fabrication method further includes:

[0026] A second LED unit layer is prepared, the second LED unit layer comprising a plurality of second LED units arranged at intervals and a filler layer located between adjacent second LED units;

[0027] The second LED unit layer is bonded to the first LED unit layer, wherein the filler layer is bonded to the first passivation layer;

[0028] In this embodiment, multiple second LED units are electrically connected to the substrate to achieve individual driving.

[0029] In one possible implementation of the second aspect, the step of fabricating the first LED unit layer includes:

[0030] A first substrate is provided, on which a first LED epitaxial layer is disposed;

[0031] The first LED epitaxial layer (the side facing away from the first substrate) is etched to form a plurality of first LED units;

[0032] A first passivation layer is formed, which covers the surface of the etched first LED epitaxial layer and exposes a portion of the surface of a plurality of first LED units on the side opposite to the first substrate.

[0033] In one possible implementation of the second aspect, the step of fabricating the first LED unit layer further includes:

[0034] A first electrode layer is formed on the side of the first passivation layer away from the first LED unit. The first electrode layer surrounds the side of the first LED unit and the side away from the first substrate. The first electrode layer also covers the surface of the area of ​​the first LED unit away from the first substrate that is not covered by the first passivation layer.

[0035] A planarization layer is formed, which covers the first passivation layer and the first electrode layer;

[0036] A first conductive bump and a conductive pillar are formed. One end of the first conductive bump is connected to the first electrode layer, and the other end extends vertically to the surface of the planarization layer opposite to the first substrate. The conductive pillar penetrates the planarization layer and the first passivation layer vertically.

[0037] In one possible implementation of the second aspect, in the step of bonding the first LED unit layer to the substrate, the conductive pillar is electrically connected to the corresponding first contact bond; and the first substrate and part of the first LED epitaxial layer are removed until the surface of the first passivation layer is exposed, so that the surfaces of the first passivation layer, the first LED unit and the conductive pillar on the side away from the substrate are flush.

[0038] In one possible implementation of the second aspect, the step of fabricating the second LED unit layer includes:

[0039] A second substrate is provided, on which a second LED epitaxial layer is disposed;

[0040] The second LED epitaxial layer (the side facing away from the second substrate) is etched to form a plurality of second LED units;

[0041] A second passivation layer is formed, which covers the surface of the etched second LED epitaxial layer and exposes a portion of the surface of a plurality of second LED units on the side opposite to the second substrate;

[0042] A second electrode layer is formed on the side of the second passivation layer away from the second LED unit. The second electrode layer surrounds the side of the second LED unit and the side away from the second substrate. The second electrode layer covers the surface of the area of ​​the second LED unit away from the second substrate that is not covered by the second passivation layer.

[0043] A filler layer is formed, which covers the second passivation layer and the second electrode layer;

[0044] A second conductive protrusion is formed in the filler layer. One end of the second conductive protrusion is electrically connected to the second electrode layer, and the other end extends vertically to the surface of the filler layer on the side opposite to the second substrate.

[0045] In one possible implementation of the second aspect, the micro-light-emitting diode display further includes conductive pillars, and the step of bonding the second LED unit layer to the first LED unit layer includes:

[0046] The filler layer is bonded to the first passivation layer, and the second conductive protrusion is bonded to and electrically connected to the end of the conductive post facing away from the substrate.

[0047] Remove the second substrate and part of the second LED epitaxial layer until the surface of the second passivation layer is exposed, so that the surfaces of the second passivation layer and the second LED unit on the side away from the substrate are flush.

[0048] In one possible implementation of the second aspect, after the step of bonding the second LED unit layer to the first LED unit layer, the fabrication method further includes:

[0049] The second LED unit layer is etched to expose the surface of the first LED unit facing away from the substrate;

[0050] A common electrode layer is formed, which at least covers the surface of the first LED unit and the second LED unit on the side opposite to the substrate, and the common electrode layer is electrically connected to the second contact of the substrate.

[0051] In one possible implementation of the second aspect, the preparation method further includes:

[0052] A protective layer is formed, which at least covers the common electrode layer;

[0053] A color conversion unit is formed in the protective layer, and the color conversion unit is located above a portion of the first LED unit or a portion of the second LED unit.

[0054] The miniature light-emitting diode display and its fabrication method provided in this application can achieve at least the following technical effects:

[0055] By using a first passivation layer located on the surface of the first LED unit layer facing away from the substrate, and exposing the surfaces of multiple first LED units facing away from the substrate, the first passivation layer can serve as a processing position reference during the fabrication of the first LED unit layer. This reduces the difficulty and cost of the processing process and minimizes the risk of device damage due to over-processing, thus protecting the first LED units during processing and improving overall yield. By covering at least the sides of multiple first LED units with the first passivation layer, the first LED units are protected, and leakage current is avoided or reduced, improving the stability and reliability of the display. Bonding the leveling layer to the first passivation layer enables bonding between the first LED unit layer and the second LED unit layer, further reducing processing difficulty and cost, improving overall yield, and reducing the thickness of the display in the vertical direction, thereby reducing the size of the display.

[0056] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0057] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0058] Figure 1 is a schematic structural diagram of a display provided in an embodiment of this disclosure;

[0059] Figure 2 is a schematic structural diagram of the structure in the process of preparing the first LED unit layer according to an embodiment of this disclosure;

[0060] Figure 3 is a schematic structural diagram of the process of preparing the first LED unit layer according to the embodiment of this disclosure;

[0061] Figure 4 is a schematic structural diagram of the process of preparing the first LED unit layer according to the embodiment of this disclosure;

[0062] Figure 5 is a schematic structural diagram of the process of preparing the first LED unit layer according to the embodiment of this disclosure;

[0063] Figure 6 is a schematic structural diagram of the process of preparing the first LED unit layer according to the embodiment of this disclosure;

[0064] Figure 7 is a schematic structural diagram of the structure in the process of preparing the first LED unit layer according to the embodiment of this disclosure;

[0065] Figure 8 is a schematic structural diagram of the structure in the process of preparing the first LED unit layer according to the embodiment of this disclosure;

[0066] Figure 9 is a schematic structural diagram of the structure in the process of preparing the first LED unit layer according to the embodiment of this disclosure;

[0067] Figure 10 is a schematic structural diagram of the process of preparing the second LED unit layer according to an embodiment of this disclosure;

[0068] Figure 11 is a schematic structural diagram of the process of preparing the second LED unit layer according to an embodiment of this disclosure;

[0069] Figure 12 is a schematic structural diagram of the process of preparing the second LED unit layer according to the embodiment of this disclosure;

[0070] Figure 13 is a schematic structural diagram of the process of preparing the second LED unit layer according to the embodiment of this disclosure;

[0071] Figure 14 is a schematic structural diagram of the process of preparing the second LED unit layer according to the embodiments of this disclosure;

[0072] Figure 15 is a schematic structural diagram of the process of preparing the second LED unit layer according to the embodiments of this disclosure;

[0073] Figure 16 is a schematic structural diagram of the process of preparing the second LED unit layer according to the embodiments of this disclosure;

[0074] Figure 17 is a schematic structural diagram of the process of preparing the second LED unit layer according to the embodiment of this disclosure;

[0075] Figure 18 is a schematic structural diagram of the first LED unit layer being bonded to the substrate according to an embodiment of this disclosure.

[0076] Figure 19 is a schematic structural diagram of the first LED unit layer being bonded to the substrate according to an embodiment of this disclosure.

[0077] Figure 20 is a schematic structural diagram of the process of bonding the second LED unit layer to the first LED unit layer according to an embodiment of this disclosure;

[0078] Figure 21 is a schematic structural diagram of the process of bonding the second LED unit layer to the first LED unit layer according to an embodiment of this disclosure;

[0079] Figure 22 is a schematic structural diagram showing the formation of a common electrode layer on the structure provided in the embodiment shown in Figure 21;

[0080] Figure 23 is a schematic structural diagram showing the formation of a protective layer on the structure provided in the embodiment shown in Figure 22;

[0081] Figure 24 is a schematic structural diagram of the etching window in the protective layer;

[0082] Figure 25 is a schematic structural diagram of a display provided in another embodiment of this disclosure;

[0083] Figure 26 is a flowchart of a method for manufacturing a display according to an embodiment of the present disclosure;

[0084] Figure 27 is a flowchart of a method for preparing a first LED unit layer according to an embodiment of this disclosure;

[0085] Figure 28 is a flowchart of a method for preparing a second LED unit layer according to an embodiment of this disclosure;

[0086] Figure 29 is a flowchart of a method for manufacturing a display according to another embodiment of this disclosure;

[0087] Figure 30 is a flowchart of a method for manufacturing a display according to another embodiment of this disclosure.

[0088] The reference numerals in the attached figures are as follows: 1: Display; 10: Substrate; 11: First contact; 20: First LED unit layer; 21: First passivation layer; 22: First LED unit; 23: Planarization layer; 24: First conductive bump; 25: First electrode layer; 26: Conductive pillar; 261: First end; 262: Second end; 27: First substrate; 28: First LED epitaxial layer; 30: Second LED unit layer; 31: Second LED unit; 32: Filling layer; 33: Second passivation layer; 34: Second electrode layer; 35: Second conductive bump; 36: Second substrate; 37: Second LED epitaxial layer; 40: Common electrode layer; 41: Protective layer; 42: Color conversion unit; 50: Third LED unit layer; 51: Third LED unit; 52: Third passivation layer; 53: Filling layer; 54: Third electrode; 55: Conductive connecting pillar; 56: Third conductive bump. Detailed Implementation

[0089] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0090] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0091] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0092] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0093] Unless otherwise stated, the term "multiple" means two or more.

[0094] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0095] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0096] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.

[0097] It should be noted that, as used in the embodiments of this disclosure, the term "layer" refers to a portion of material comprising a region having a certain thickness. A layer may extend over the entire lower or upper structure, or may have a extent smaller than that of the lower or upper structure. Furthermore, a layer may be a region of a homogeneous or heterogeneous continuous structure, with a thickness less than the thickness of the continuous structure. For example, a layer may be located between the top and bottom surfaces of a continuous structure, or between any pair of horizontal planes therebetween. A layer may extend horizontally, vertically, and / or along a conical surface.

[0098] It should be noted that the term "micro" as used in the embodiments of this disclosure refers to the descriptive size of certain devices or structures according to the embodiments of this application. The term "micro" as used herein is intended to indicate a scale of 0.1 to 100 μm. However, it should be understood that the embodiments of this application are not necessarily limited thereto, and certain aspects of the embodiments can be applied to larger and possibly smaller size scales.

[0099] For the sake of simplicity, in the following description, some "miniature light-emitting diode displays" will be simplified to "displays".

[0100] According to a first aspect of the embodiments of this application, and in conjunction with FIGS. 1 to 25, a micro light-emitting diode display 1 is provided, comprising a substrate 10, a first LED unit layer 20, and a second LED unit layer 30. The first LED unit layer 20 is bonded to the substrate 10. The second LED unit layer 30 includes a first passivation layer 21 and a plurality of first LED units 22 arranged at intervals. The first passivation layer 21 is located on the surface of the first LED unit layer 20 facing away from the substrate 10, and exposes the surface of the plurality of first LED units 22 facing away from the substrate 10. The first passivation layer 21 also covers at least the side surfaces of the plurality of first LED units 22. The second LED unit layer 30 is bonded to the first LED unit layer 20. The second LED unit layer 30 includes a plurality of second LED units 31 arranged at intervals and a leveling layer 32 located between adjacent second LED units 31. The leveling layer 32 is bonded to the first passivation layer 21. The plurality of first LED units 22 and the plurality of second LED units 31 are electrically connected to the substrate 10 respectively, enabling individual driving.

[0101] By using the first passivation layer 21 located on the surface of the first LED unit layer 20 facing away from the substrate 10, the first passivation layer 21 exposes the surface of the plurality of first LED units 22 facing away from the substrate 10. In order to make the first passivation layer 21 a processing position reference when fabricating the micro light-emitting diode display 1, the first passivation layer 21 can be used as a processing position reference, reducing the processing difficulty and processing cost, and avoiding or reducing the situation of device damage caused by over-processing, so as to protect the first LED unit 22 during the processing and improve the overall yield.

[0102] For example, after the first LED unit layer 20 is bonded to the substrate 10, a portion of the first LED epitaxial layer 28 can be removed by chemical mechanical polishing (CMP). During CMP processing, the first passivation layer 21 serves as a processing position reference; that is, CMP processing stops when the first passivation layer 21 is exposed, reducing the processing difficulty and cost. Furthermore, by providing a clear reference position through the first passivation layer 21, damage to the device due to over-processing is avoided or reduced, effectively protecting the first LED unit 22 during processing and improving the overall yield.

[0103] The first passivation layer 21 is located on the surface of the first LED unit layer 20 facing away from the substrate 10, allowing the leveling layer 32 to bond smoothly to the first passivation layer 21. Bonding the leveling layer 32 to the first passivation layer 21 achieves bonding between the first LED unit layer 20 and the second LED unit layer 30, further reducing processing difficulty and cost, and improving overall yield. It also reduces the thickness of the display 1 in the vertical direction, thereby reducing the size of the display 1.

[0104] The first passivation layer 21 covers at least the sides of the plurality of first LED units 22. For example, the first passivation layer 21 may cover the sides of the plurality of first LED units 22 and a portion of the surface of the plurality of first LED units 22 facing the substrate 10. By covering at least the sides of the plurality of first LED units 22 with the first passivation layer 21, the first LED units 22 are protected. Furthermore, when the first LED units 22 are connected to electrodes, the first passivation layer 21 can also prevent or reduce leakage current, thereby improving the stability and reliability of the display 1.

[0105] The miniature light-emitting diode display 1 includes a substrate 10, a first LED unit layer 20, and a second LED unit layer 30. The first LED unit layer 20 is bonded to the substrate 10, and the second LED unit layer 30 is bonded to the first LED unit layer 20. This reduces the thickness of the display 1 in the vertical direction, thereby reducing the size of the display 1. Furthermore, the manufacturing process is simple, the cost is low, and it is economical.

[0106] By electrically connecting multiple first LED units 22 and multiple second LED units 31 to the substrate 10, each first LED unit 22 can be driven by the substrate 10 individually, and each second LED unit 31 can be driven by the substrate 10 individually.

[0107] It should be noted that the vertical direction can be understood as the direction that is perpendicular to or nearly perpendicular to the upper surface of the substrate 10, that is, the direction from top to bottom in Figures 1 and 25.

[0108] In this embodiment, substrate 10 refers to the material on which subsequent material layers are added. Substrate 10 itself may be patterned. The material added to the top of substrate 10 may be patterned or may remain unpatterned. Furthermore, substrate 10 may comprise a wide variety of semiconductor materials, such as silicon, silicon carbide, gallium nitride, germanium, gallium arsenide, and indium phosphide. Alternatively, substrate 10 may be made of a non-conductive material, such as glass, plastic, or sapphire wafer. Further alternatively, substrate 10 may have semiconductor devices or circuits formed therein.

[0109] In addition, the substrate 10 may be provided with a circuit layer including complementary metal oxide semiconductor (CMOS) devices or thin film field effect transistor (TFT) devices, which can constitute a driving circuit.

[0110] In one possible implementation, as shown in Figures 1 and 25, the projections of the first LED unit 22 and the second LED unit 31 onto the substrate 10 do not overlap along the vertical direction. The first LED unit 22 is used to emit a first color light, and the second LED unit 31 is used to emit a second color light, wherein the first color light and the second color light are different.

[0111] By ensuring that the vertical projections of the first LED unit 22 and the second LED unit 31 onto the substrate 10 do not overlap, the brightness and color distribution of the displayed colors are made more uniform, thus enhancing the user's visual experience.

[0112] The first color light and the second color light are different to achieve multi-color display. For example, the first color light is blue light and the second color light is green light. Or, the first color light is blue light and the second color light is red light. Or, the first color light is green light and the second color light is blue light. Or, the first color light is green light and the second color light is red light. Or, the first color light is red light and the second color light is green light. Or, the first color light is red light and the second color light is blue light.

[0113] In one possible implementation, the material of the first passivation layer 21 includes aluminum oxide (Al2O3) or silicon dioxide (SiO2).

[0114] In one possible implementation, the material of the leveling layer 32 includes silicon dioxide (SiO2), silicon nitride, or benzocyclobutene (BCB).

[0115] It is understood that the shapes of the first LED unit 22 and the second LED unit 31 are not limited. For example, they can be frustum-shaped or cube-shaped, etc.

[0116] In some embodiments, as shown in Figures 1 and 25, the substrate 10 includes a plurality of first contacts 11. The first LED unit layer 20 further includes a planarization layer 23 and a first conductive protrusion 24. The planarization layer 23 is disposed on the side of the first passivation layer 21 facing the substrate 10, and the planarization layer 23 is bonded to the substrate 10. The first conductive protrusion 24 is disposed on the planarization layer 23. One end of the first conductive protrusion 24 is electrically connected to the first LED unit 22, and the other end is bonded and electrically connected to the corresponding first contact 11.

[0117] The planarization layer 23 is disposed on the side of the first passivation layer 21 facing the substrate 10, which enables the planarization layer 23 to be smoothly bonded to the substrate 10, reducing the processing difficulty and cost. It can also reduce the overall thickness of the display 1 in the vertical direction, thereby reducing the size of the display 1.

[0118] The first conductive protrusion 24 is disposed on the planarization layer 23. Specifically, the first conductive protrusion 24 is disposed on the side of the first LED unit layer 20 facing the substrate 10. This allows one end of the first conductive protrusion 24 to be smoothly electrically connected to the first LED unit 22, and the other end of the first conductive protrusion 24 to be smoothly bonded and electrically connected to the corresponding first contact 11. Consequently, the first contact 11 of the substrate 10 can apply a voltage to the first LED unit 22 individually, thereby driving the first LED unit 22 individually.

[0119] It should be noted that the bonding between the first conductive protrusion 24 and the corresponding first contact 11 means that each first contact 11 is electrically connected to only one first LED unit 22 or second LED unit layer 30. Therefore, each first conductive protrusion 24 is used to connect a first LED unit 22 and its corresponding first contact 11.

[0120] In one possible implementation, the material of the planarization layer 23 includes silicon dioxide (SiO2), silicon nitride, or benzocyclobutene (BCB).

[0121] In one possible implementation, the material of the first conductive protrusion 24 includes copper (Cu).

[0122] In one possible implementation, as shown in Figures 1 and 18 to 25, the surface area of ​​the first conductive protrusion 24 bonded to the first contact 11 is greater than the surface area of ​​the side connected to the first LED unit 22.

[0123] Referring to Figures 1, 18, and 19, A illustrates the bonding side between the first conductive protrusion 24 and the first contact 11, and B illustrates the connection side between the first conductive protrusion 24 and the first LED unit 22. By having a larger surface area at the lower end of the first conductive protrusion 24 than at the upper end, the size of the display 1 can be reduced to a certain extent. Furthermore, the bonding accuracy between the first conductive protrusion 24 and the first contact 11 can be improved, allowing for the integration of more first LED units 22 within the same display area, increasing pixel density, and consequently improving the device's resolution and display effect.

[0124] In one possible implementation, the display 1 further includes a first bonding layer disposed between the first LED unit layer 20 and the substrate 10. The first bonding layer has a plurality of spaced-apart pads. In the vertical direction, the pads penetrate the first bonding layer. One side of the first bonding layer is bonded to the substrate 10, and the other side is bonded to the planarization layer 23 of the first LED unit layer 20. One end of the pad is bonded and electrically connected to a first contact 11 of the substrate 10, and the other end of the pad is bonded and electrically connected to a first conductive protrusion 24, thereby bonding the first LED unit layer 20 to the substrate 10.

[0125] It should be noted that the material of the first bonding layer is not limited, for example, silicon dioxide. The material of the solder pads is not limited, for example, copper.

[0126] In some embodiments, as shown in Figures 1, 5 to 9, and 18 to 25, the first LED unit layer 20 further includes a first electrode layer 25. The first electrode layer 25 is disposed on the side of the first passivation layer 21 opposite to the first LED unit 22, and surrounds the side of the first LED unit 22 and the side facing the substrate 10. The first electrode layer 25 covers the surface of the first LED unit 22 on the side facing the substrate 10 that is not covered by the first passivation layer 21. The first electrode layer 25 reflects the light emitted by the first LED unit 22.

[0127] The first electrode layer 25 is disposed around the side surface of the first LED unit 22 and the side facing the substrate 10. Referring to Figure 1, the first electrode layer 25 surrounds the side surface and bottom surface of the first LED unit 22 to form a reflective cup on the side surface and bottom surface of the first LED unit 22. This allows the first electrode layer 25 to reflect the light emitted by the first LED unit 22, improving light extraction efficiency and preventing or reducing optical crosstalk. The reflective cup also reduces light hitting adjacent first LED units 22, further improving light extraction efficiency. Furthermore, the reflective cup can concentrate the light spot and make the pixels more compact. While reducing the size of the display 1, more first LED units 22 can be integrated on the same display area, increasing pixel density and improving the resolution and display effect of the device.

[0128] The first electrode layer 25 covers the surface of the first LED unit 22 on the side facing the substrate 10 that is not covered by the first passivation layer 21, thereby achieving electrical connection between the first electrode layer 25 and the first LED unit 22. Referring to Figure 1, the first electrode layer 25 is electrically connected to the bottom position of the first LED unit 22.

[0129] The first electrode layer 25 is disposed on the side of the first passivation layer 21 facing away from the first LED unit 22. That is, on the side and bottom surfaces of the first LED unit 22, except at the locations where the first electrode layer 25 is electrically connected to the first LED unit 22, the first passivation layer 21 is provided between the first electrode layer 25 and the first LED unit 22. The first passivation layer 21 protects the first LED unit 22, and also prevents or reduces leakage current, thereby improving the stability and reliability of the display 1.

[0130] It should be noted that the material of the first electrode layer 25 is not limited; for example, it can be aluminum or silver.

[0131] In one possible implementation, as shown in FIG1 and FIG18 to FIG25, the side of the first electrode layer 25 facing away from the first LED unit 22 is electrically connected to the end of the first conductive protrusion 24 facing away from the first contact 11. That is, the first contact 11 is electrically connected to the first LED unit 22 through the first conductive protrusion 24 and the first electrode layer 25 to apply voltage to the first LED unit 22 individually.

[0132] In some embodiments, as shown in Figures 1, 12 to 17, and 20 to 25, the second LED unit layer 30 further includes a second passivation layer 33. The second passivation layer 33 is disposed on the surface of the leveling layer 32 facing away from the substrate 10, and exposes the surface of the plurality of second LED units 31 facing away from the substrate 10. Furthermore, the second passivation layer 33 also covers at least the sides of the plurality of second LED units 31.

[0133] The second passivation layer 33 is disposed on the surface of the leveling layer 32 away from the substrate 10, and exposes the surface of the second LED units 31 away from the substrate 10. In order to make the second passivation layer 33 a processing position reference when fabricating the micro light-emitting diode display 1, the processing difficulty and processing cost are reduced, and the situation of device damage caused by over-processing is avoided or reduced, so as to protect the second LED units 31 during the processing and improve the overall yield.

[0134] In a specific example, when fabricating a micro LED display 1, a first LED unit layer 20 is first bonded to a substrate 10, and then a second LED unit layer 30 is bonded to the first LED unit layer 20. After the second LED unit layer 30 is bonded to the first LED unit layer 20, a portion of the first LED epitaxial layer 28 can be removed by chemical mechanical polishing (CMP). CMP processing stops when the first passivation layer 21 is exposed, avoiding or reducing over-processing, effectively protecting the first LED unit 22, and reducing the processing difficulty and cost. This provides a connection surface for bonding the second LED unit layer 30 to the first LED unit layer 20, enabling the first LED unit 22 to emit light effectively. After the second LED unit layer 30 is bonded to the first LED unit layer 20, a portion of the second LED epitaxial layer 37 can be removed by CMP processing. CMP processing stops when the second passivation layer 33 is exposed, avoiding or reducing over-processing, effectively protecting the second LED unit 31, and reducing the processing difficulty and cost. By using the first passivation layer 21 and the second passivation layer 33 together as a reference for the processing position in different processing steps, the overall processing difficulty is reduced and the yield is improved.

[0135] In another specific example, when the display 1 also includes a third LED unit layer 50, by disposing the second passivation layer 33 on the surface of the leveling layer 32 facing away from the substrate 10, the second passivation layer 33 and the third LED unit layer 50 can be smoothly bonded, reducing processing difficulty and cost, and improving overall yield. Furthermore, the thickness of the display 1 is reduced in the vertical direction, thereby reducing the size of the display 1.

[0136] The second passivation layer 33 covers at least the sides of the plurality of second LED units 31. For example, the second passivation layer 33 may cover the sides of the plurality of second LED units 31 and a portion of the surface of the plurality of second LED units 31 facing the substrate 10. By covering at least the sides of the plurality of second LED units 31 with the second passivation layer 33, the second LED units 31 are protected. Furthermore, when the second LED units 31 are connected to electrodes, the second passivation layer 33 can also prevent or reduce leakage current, thereby improving the stability and reliability of the display 1.

[0137] In one possible implementation, the material of the second passivation layer 33 includes aluminum oxide (Al2O3) or silicon dioxide (SiO2).

[0138] In some embodiments, as shown in Figures 1, 13 to 17, and 20 to 25, the second LED unit layer 30 further includes a second electrode layer 34. The second electrode layer 34 is disposed on the side of the second passivation layer 33 opposite to the second LED unit 31, and surrounds the side surface of the second LED unit 31 and the side facing the substrate 10. The second electrode layer 34 covers the surface of the second LED unit 31 on the side facing the substrate 10 that is not covered by the second passivation layer 33. The second electrode layer 34 reflects the light emitted by the second LED unit 31.

[0139] The second electrode layer 34 is disposed around the side surface of the second LED unit 31 and the side facing the substrate 10. Referring to Figure 1, the second electrode layer 34 surrounds the side surface and bottom surface of the second LED unit 31 to form a reflective cup on the side surface and bottom surface of the second LED unit 31. This allows the second electrode layer 34 to reflect the light emitted by the second LED unit 31, improving light extraction efficiency and preventing or reducing optical crosstalk. The reflective cup also reduces light hitting adjacent second LED units 31, further improving light extraction efficiency. Furthermore, the reflective cup can concentrate the light spot and make the pixels more compact. While reducing the size of the display 1, more second LED units 31 can be integrated on the same display area, increasing pixel density and improving the resolution and display effect of the device.

[0140] The second electrode layer 34 covers the surface of the second LED unit 31 facing the substrate 10 but not covered by the second passivation layer 33, thereby achieving electrical connection between the second electrode layer 34 and the second LED unit 31. Referring to Figure 1, the second electrode layer 34 is electrically connected to the bottom position of the second LED unit 31.

[0141] The second electrode layer 34 is disposed on the side of the second passivation layer 33 facing away from the second LED unit 31. That is, on the side and bottom surfaces of the first LED unit 22, except at the locations where the second electrode layer 34 is electrically connected to the second LED unit 31, the second passivation layer 33 is provided between the second electrode layer 34 and the second LED unit 31. The second passivation layer 33 protects the second LED unit 31, prevents or reduces leakage, and improves the stability and reliability of the display 1.

[0142] It should be noted that the material of the second electrode layer 34 is not limited; for example, it can be aluminum or silver.

[0143] In some embodiments, as shown in Figures 1, 9, and 18 to 25, the micro LED display 1 further includes a conductive post 26. The conductive post 26 extends vertically through the first LED unit layer 20. One end of the conductive post 26 is electrically connected to the substrate 10, and the other end is electrically connected to a corresponding second LED unit 30. Specifically, the conductive post 26 includes a first end 261 and a second end 262, and the first end 261 of the conductive post 26 is bonded to a first contact 11 of the corresponding substrate 10. The second LED unit layer 30 also includes a second conductive protrusion 35 disposed on the filler layer 32. The second conductive protrusion 35 is electrically connected to the second LED unit 30. Specifically, one end of the second conductive protrusion 35 is electrically connected to the second electrode layer 34, and the other end of the second conductive protrusion 35 is bonded to and electrically connected to the second end 262 of the conductive post 26.

[0144] The conductive post 26 penetrates vertically through the first LED unit layer 20. As shown in Figure 1, the conductive post 26 penetrates the first LED unit layer 20 from top to bottom, so that the first end 261 of the conductive post 26 can be smoothly bonded and electrically connected to the first contact 11 directly below it, and the second end 262 of the conductive post 26 can be smoothly bonded and electrically connected to the second conductive protrusion 35 directly above it. Furthermore, the end of the second conductive protrusion 35 facing away from the conductive post 26 is electrically connected to the second electrode layer 34, and the second electrode layer 34 is electrically connected to the second LED unit 31. This allows the first contact 11 of the substrate 10 to apply voltage to the second LED unit 31 individually, so that the second LED unit 31 can be driven individually.

[0145] The second conductive protrusion 35 is disposed on the filler layer 32. Specifically, the second conductive protrusion 35 is disposed on the side of the second LED unit layer 30 facing the substrate 10. This allows one end of the second conductive protrusion 35 to be smoothly electrically connected to the second electrode layer 34, and the other end of the second conductive protrusion 35 to be smoothly bonded and electrically connected to the second end 262 of the conductive post 26, reducing the processing difficulty.

[0146] It should be noted that the bonding between the first end 261 of the conductive post 26 and the corresponding first contact 11 means that each first contact 11 is electrically connected to only one first LED unit 22 or second LED unit layer 30. Therefore, each conductive post 26 and each second conductive protrusion 35 are used to connect a second LED unit 31 and its corresponding first contact 11.

[0147] In one possible implementation, the material of the second conductive protrusion 35 includes copper (Cu).

[0148] In one possible implementation, the micro LED display 1 further includes a second bonding layer disposed between the first LED unit layer 20 and the second LED unit layer 30. The second bonding layer has a plurality of spaced-apart pads. In the vertical direction, the pads penetrate the second bonding layer. One side of the second bonding layer is bonded to the first passivation layer 21, and the other side is bonded to the filler layer 32 of the second LED unit layer 30. One end of the pad is bonded and electrically connected to the second end 262 of the conductive post 26, and the other end of the pad is bonded and electrically connected to the second conductive protrusion 35, thereby bonding the second LED unit layer 30 to the first LED unit layer 20.

[0149] It should be noted that the material of the second bonding layer is not limited, for example, silicon dioxide. The material of the solder pads is not limited, for example, copper.

[0150] In some embodiments, as shown in FIG1 and FIG21, the surface area of ​​the second conductive protrusion 35 bonded to the conductive post 26 is greater than the surface area of ​​the side connected to the second electrode layer 34.

[0151] In Figure 21, C indicates the bonding side between the second conductive protrusion 35 and the conductive post 26, and D indicates the connection side between the second conductive protrusion 35 and the second electrode layer 34. By making the surface area of ​​the lower end of the second conductive protrusion 35 larger than that of the upper end, the size of the display 1 can be reduced to a certain extent. It can also improve the bonding accuracy between the second conductive protrusion 35 and the conductive post 26, so as to integrate more second LED units 31 on the same display area, increase pixel density, and thus improve the resolution and display effect of the device.

[0152] In some embodiments, the first LED unit 22 and the second LED unit 31 respectively include a first doped semiconductor layer, an active layer, and a second doped semiconductor layer stacked together. The first doped semiconductor layer is close to the substrate 10. The surface of the second doped semiconductor layer of the first LED unit 22 facing away from the substrate 10 is flush with the surface of the first passivation layer 21 facing away from the substrate 10. The surface of the second doped semiconductor layer of the second LED unit 31 facing away from the substrate 10 is flush with the surface of the second passivation layer 33 facing away from the substrate 10.

[0153] Specifically, the first LED unit 22 includes a first doped semiconductor layer, an active layer, and a second doped semiconductor layer stacked together. The second LED unit 31 includes a first doped semiconductor layer, an active layer, and a second doped semiconductor layer stacked together. The first doped semiconductor layer is close to the substrate 10, that is, the second doped semiconductor layer is away from the substrate 10, so as to achieve smooth electrical connection between the first doped semiconductor layer and the substrate 10, and to enable the second doped semiconductor layer to be effectively protected by the first passivation layer 21 or the second passivation layer 33, thereby improving the yield.

[0154] By aligning the surface of the second doped semiconductor layer of the first LED unit 22 on the side opposite to the substrate 10 with the surface of the first passivation layer 21 on the side opposite to the substrate 10, the first passivation layer 21 can serve as a processing position reference during the fabrication of the micro LED display 1, thereby protecting the second doped semiconductor layer, avoiding or reducing the possibility of damage to the second doped semiconductor layer due to over-processing, reducing processing difficulty, and improving overall yield.

[0155] By aligning the surface of the second doped semiconductor layer of the second LED unit 31 on the side opposite to the substrate 10 with the surface of the second passivation layer 33 on the side opposite to the substrate 10, the second passivation layer 33 can serve as a processing position reference during the fabrication of the micro LED display 1, thereby protecting the second doped semiconductor layer, avoiding or reducing the possibility of damage to the second doped semiconductor layer due to over-processing, reducing processing difficulty, and improving overall yield.

[0156] The first doped semiconductor layer can be a p-type semiconductor layer, specifically p-type gallium nitride (GaN) or p-type aluminum indium gallium nitride (AlInGaN). Correspondingly, the second doped semiconductor layer can be an n-type semiconductor layer, specifically n-type gallium nitride (GaN) or n-type aluminum indium gallium nitride (AlInGaN).

[0157] In some embodiments, the substrate 10 includes at least one second contact (not shown). The micro LED display 1 also includes a common electrode layer 40, which is electrically connected to the surface of the first LED unit 22 and the second LED unit 31 on the side opposite to the substrate 10, and is also electrically connected to the second contact.

[0158] Specifically, the common electrode layer 40 covers the surface of the first LED unit 22 facing away from the substrate 10 and is electrically connected to the first LED unit 22. Simultaneously, the common electrode layer 40 also covers the surface of the second LED unit 31 facing away from the substrate 10 and is electrically connected to the second LED unit 31. By electrically connecting the same common electrode layer 40 to the surfaces of both the first LED unit 22 and the second LED unit 31 facing away from the substrate 10, the thickness of the display 1 is reduced in the vertical direction, thus reducing the overall size of the display 1.

[0159] The first LED unit 22 and the second LED unit 31 are electrically connected to the second contact through the common electrode layer 40, and each first LED unit 22 and each second LED unit 31 are individually electrically connected to the corresponding first contact 11, so that each first LED unit 22 and each second LED unit 31 can be driven individually.

[0160] In a specific example, the first contact 11 is an anode metal contact, and the second contact is a cathode metal contact. The first doped semiconductor layer is a p-type semiconductor layer, and the second doped semiconductor layer is an n-type semiconductor layer. The first contact 11 is electrically connected to the first doped semiconductor layer of a first LED unit 22 through a first conductive bump 24 and a first electrode layer 25. The second doped semiconductor layers of multiple first LED units 22 are electrically connected to the second contact through a common electrode layer 40 (forming a common cathode structure) to drive the active layer of the first LED unit 22 to emit light, for example, emitting green, blue, or red light.

[0161] In another specific example, the first contact 11 is an anode metal contact, and the second contact is a cathode metal contact. The first doped semiconductor layer is a p-type semiconductor layer, and the second doped semiconductor layer is an n-type semiconductor layer. The first contact 11 is electrically connected to the first doped semiconductor layer of a second LED unit 31 through a conductive post 26, a second conductive protrusion 35, and a second electrode layer 34. The second doped semiconductor layers of multiple second LED units 31 are electrically connected to the second contact through a common electrode layer 40 (forming a common cathode structure) to drive the active layer of the second LED unit 31 to emit light, for example, emitting green, blue, or red light.

[0162] It should be noted that the common electrode layer 40 is specifically a transparent common electrode layer 40, so that the light from the first LED unit 22 and the second LED unit 31 can be emitted smoothly. The material of the common electrode layer 40 is not limited; for example, it can be indium tin oxide (ITO).

[0163] In some embodiments, as shown in FIG. 1, the display 1 further includes a plurality of color conversion units 42. The plurality of color conversion units 42 are arranged at intervals on the side of the second LED unit layer 30 facing away from the substrate 10, and are located on a portion of the first LED units 22 or a portion of the second LED units 31. The color conversion units 42 are used to convert a first color light emitted by the first LED unit 22 or a second color light emitted by the second LED unit 31 into a third color light. The first color light, the second color light, and the third color light are different. At least one first LED unit 22, at least one adjacent second LED unit 31, and at least one adjacent color conversion unit 42 constitute a full-color pixel.

[0164] Multiple color conversion units 42 are spaced apart on the side of the second LED unit layer 30 facing away from the substrate 10, and are located above some of the first LED units 22 or some of the second LED units 31. Specifically, color conversion units 42 are provided on some of the first LED units 22, and / or color conversion units 42 are provided on some of the second LED units 31. Of course, the vertical projections of the color conversion units 42 and the lower first LED units 22 on the substrate 10 can partially or completely overlap, and the vertical projections of the color conversion units 42 and the lower second LED units 31 on the substrate 10 can partially or completely overlap.

[0165] When the color conversion unit 42 is located above the first LED unit 22, the color conversion unit 42 is used to convert the first color light emitted by the first LED unit 22 into a third color light. For example, the color conversion unit 42 converts the green light emitted by the first LED unit 22 into red light.

[0166] When the color conversion unit 42 is located above the second LED unit 31, the color conversion unit 42 is used to convert the second color light emitted by the second LED unit 31 into a third color light. For example, the color conversion unit 42 converts the blue light emitted by the second LED unit 31 into red light.

[0167] At least one first LED unit 22, together with at least one adjacent second LED unit 31 and at least one adjacent color conversion unit 42, constitute a full-color pixel. That is, full-color display is achieved through the first color light emitted by the first LED unit 22, the second color light emitted by the at least one adjacent second LED unit 31, and the third color light converted and emitted by the at least one adjacent color conversion unit 42. Color conversion is performed by mixing and bonding the first LED unit layer 20 to the substrate 10, mixing and bonding the second LED unit layer 30 to the first LED unit layer 20, and using the color conversion unit 42. In other words, through two mixing and bonding operations and one color conversion, luminous efficiency is improved and processing difficulty is reduced.

[0168] For example, as shown in Figure 1, in three adjacent sub-pixels, one is equipped with a first LED unit 22 for emitting green light, and another is equipped with a second LED unit 31 for emitting blue light. The second LED unit 31 is also equipped with a color conversion unit 42, which converts the blue light emitted by the second LED unit 31 into red light for emission, thereby achieving full-color display, improving luminous efficiency, simplifying the manufacturing process, and reducing processing difficulty and cost.

[0169] In one possible implementation, the material of the color conversion unit 42 includes quantum dot photoresist (QDPR).

[0170] In one possible implementation, as shown in Figures 1 and 25, the micro LED display 1 further includes a protective layer 41. The protective layer 41 is disposed on the common electrode layer 40 and at least covers the common electrode layer 40. A color conversion unit 42 is disposed on the protective layer 41.

[0171] The protective layer 41 can improve the integrity and stability of the display 1 and increase the light extraction rate.

[0172] It should be noted that the protective layer 41 is specifically a transparent protective layer 41, which protects the device while enabling the display 1 to emit light effectively.

[0173] In one possible implementation, the material of the protective layer 41 includes polyimide, benzocyclobutene (BCB), or leveling adhesive.

[0174] In some embodiments, as shown in FIG. 25, the display 1 further includes a third LED unit layer 50. The third LED unit layer 50 is bonded to the second LED unit layer 30. The third LED unit layer 50 includes a plurality of third LED units 51 arranged at intervals. The vertical projections of the first LED unit 22, the second LED unit 31, and the third LED unit 51 on the substrate 10 do not overlap. At least one first LED unit 22, at least one adjacent second LED unit 31, and at least one adjacent third LED unit 51 constitute a full-color pixel.

[0175] The vertical projections of the first LED unit 22, the second LED unit 31, and the third LED unit 51 on the substrate 10 do not overlap, allowing each LED unit to emit light independently, thus improving luminous efficiency and reducing crosstalk. Specifically, the first LED unit 22 emits a first color light, the second LED unit 31 emits a second color light, and the third LED unit 51 emits a third color light. The first, second, and third colors are different to achieve full-color display, improving color response speed and long-term stability. For example, the first color light could be green, the second color light blue, and the third color light red. Another example: the first color light could be green, the second color light red, and the third color light blue. Yet another example: the first color light could be blue, the second color light green, and the third color light red. Yet another example: the first color light could be blue, the second color light red, and the third color light green. Yet another example: the first color light could be red, the second color light green, and the third color light blue. For example, the first color of light is red, the second color of light is blue, and the third color of light is green.

[0176] A full-color pixel is formed by at least one first LED unit 22, at least one adjacent second LED unit 31, and at least one adjacent third LED unit 51. That is, full-color display is achieved by the first LED unit 22 emitting a first color light, the at least one adjacent second LED unit 31 emitting a second color light, and the at least one adjacent third LED unit 51 emitting a third color light.

[0177] In one possible implementation, as shown in FIG25, the third LED unit layer 50 further includes a filling layer 53 located between adjacent third LED units 51, the filling layer 53 being bonded to the second passivation layer 33, so as to achieve the bonding of the third LED unit layer 50 to the second LED unit layer 30.

[0178] In one possible implementation, as shown in FIG25, the third LED unit layer 50 further includes a third passivation layer 52 disposed on the surface of the fill layer 53 facing away from the substrate 10, and exposing the surface of the plurality of third LED units 51 facing away from the substrate 10. The third passivation layer 52 at least covers the sides of the plurality of third LED units 51.

[0179] When manufacturing the display 1, the third passivation layer 52 is used as a processing position reference to reduce the processing difficulty and processing cost, and to avoid or reduce the situation of device damage caused by over-processing, so as to protect the third LED unit 51 during the processing and improve the overall yield.

[0180] The third passivation layer 52 covers at least the sides of the plurality of third LED units 51. For example, the third passivation layer 52 may cover the sides of the plurality of third LED units 51 and a portion of the surface of the plurality of third LED units 51 facing the substrate 10. By protecting the third LED units 51 and when the third LED units 51 are connected to electrodes, the third passivation layer 52 can also avoid or reduce leakage current, thereby improving the stability and reliability of the display 1.

[0181] In one possible implementation, the material of the third passivation layer 52 includes aluminum oxide (Al2O3) or silicon dioxide (SiO2).

[0182] In one possible implementation, referring to FIG25, the third LED unit layer 50 further includes a third electrode 54. The third electrode 54 is disposed on the side of the third passivation layer 52 opposite to the third LED unit 51, and surrounds the side of the third LED unit 51 and the side facing the substrate 10. Furthermore, the third electrode 54 covers the surface of the third LED unit 51 on the side facing the substrate 10 that is not covered by the third passivation layer 52. The third electrode 54 reflects the light emitted by the third LED unit 51. The technical effects of the third electrode 54 are similar to those of the second electrode layer 34 and the first electrode layer 25 in the aforementioned embodiments, and will not be repeated here.

[0183] In one possible implementation, referring to FIG. 25, the display 1 further includes conductive connecting posts 55. Conductive posts 26 extend vertically through the second LED unit layer 30. The third LED unit layer 50 also includes a third conductive protrusion 56. One end of the conductive connecting post 55 is bonded and electrically connected to the conductive post 26, and the other end of the conductive connecting post 55 is bonded and electrically connected to the third conductive protrusion 56. The end of the third conductive protrusion 56 facing away from the conductive connecting post 55 is bonded and electrically connected to a third electrode 54, so that the third LED unit layer 50 can be driven independently by the substrate 10.

[0184] In one possible implementation, as shown in FIG25, the common electrode layer 40 is also electrically connected to the surface of the third LED unit 51 on the side opposite to the substrate 10.

[0185] Referring to Figure 26, according to a second aspect of the embodiments of this application, a method for fabricating a miniature light-emitting diode display 1 is provided, used for fabricating the display 1. The fabrication method includes the following steps:

[0186] S261, Provide a substrate.

[0187] As shown in Figure 1 and Figures 18 to 25, the first LED unit 22 and multiple second LED units 31 are individually driven through the substrate 10.

[0188] S262. Prepare a first LED unit layer, the first LED unit layer including a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on the surface of the first LED unit layer away from the substrate and exposes the surface of the plurality of first LED units away from the substrate; and the first passivation layer also covers at least the side surfaces of the plurality of first LED units.

[0189] Referring to Figures 1 to 9, by fabricating the first LED unit layer 20, preparations are made for bonding the entire first LED unit layer 20 to the substrate 10, thereby improving the yield of each structure within the first LED unit layer 20 during processing. The technical effects of the first passivation layer 21, the first LED unit 22, and their arrangement are as described in the aforementioned embodiments and will not be repeated here.

[0190] S263. Bond the first LED unit layer to the substrate.

[0191] As shown in Figures 18 and 19, by bonding the entire first LED unit layer 20 to the substrate 10, the processing technology is simplified, the processing difficulty is reduced, and the yield is improved.

[0192] S264. Prepare a second LED unit layer, the second LED unit layer comprising a plurality of second LED units arranged at intervals and a filler layer located between adjacent second LED units.

[0193] Referring to Figures 1 and 10 to 17, the fabrication of the second LED unit layer 30 prepares for bonding the entire second LED unit layer 30 to the first LED unit layer 20, thereby improving the yield of each structure within the second LED unit layer 30 during processing. The effects of the leveling layer 32, the first LED unit 22, and their configuration are described in the aforementioned embodiments and will not be repeated here.

[0194] S265. The second LED unit layer is bonded to the first LED unit layer, wherein the filler layer is bonded to the first passivation layer.

[0195] In this embodiment, multiple first LED units 22 and multiple second LED units 31 are electrically connected to the substrate 10 to achieve individual driving.

[0196] As shown in Figures 20 and 21, by bonding the entire second LED unit layer 30 to the first LED unit layer 20, the processing technology is simplified, the processing difficulty is reduced, and the yield is improved.

[0197] In some embodiments, as shown in Figures 2 to 4, the steps for fabricating the first LED unit layer 20 include: providing a first substrate 27 on which a first LED epitaxial layer 28 is disposed; etching the side of the first LED epitaxial layer 28 away from the first substrate 27 to form a plurality of first LED units 22; and forming a first passivation layer 21, which covers the surface of the first LED epitaxial layer 28 away from the first substrate 27 and the surfaces of the plurality of first LED units 22, and exposes a portion of the surface of the plurality of first LED units 22 away from the first substrate 27.

[0198] As shown in Figure 2, the first substrate 27 provides support, making the entire first LED unit layer 20 structure more stable. For example, a first LED epitaxial layer 28 can be grown on the first substrate 27, which provides stable support for the growth of the first LED epitaxial layer 28.

[0199] It should be noted that the material of the first substrate 27 is not limited; for example, it can be silicon, sapphire, or gallium nitride. The material of the first LED epitaxial layer 28 is not limited; for example, it can be gallium nitride (GaN).

[0200] As shown in Figure 3, by etching the side of the first LED epitaxial layer 28 away from the first substrate 27, multiple mesa structures (MESAs) are formed on the first LED epitaxial layer 28. Each mesa structure is a complete first LED unit 22, that is, the first LED unit 22 can be independently driven and emit light by the substrate 10. Specifically, the multiple first LED units 22 are arranged at intervals.

[0201] As shown in Figure 4, a first passivation layer 21 can be formed on the surface of the first LED epitaxial layer 28 facing away from the first substrate 27 by depositing a material (e.g., alumina or silicon dioxide). The first passivation layer 21 covers the surface of the first LED epitaxial layer 28 facing away from the first substrate 27 and the surfaces of the multiple first LED units 22. The first passivation layer 21 is etched to form multiple windows; G1 in Figure 4 illustrates the windows formed by etching the first passivation layer 21. Each window exposes a portion of the surface of the multiple first LED units 22 facing away from the first substrate 27, preparing the structure for subsequent electrical connection between the first LED units 22 and the first electrode layer 25.

[0202] In some embodiments, as shown in Figures 5 to 9, the step of fabricating the first LED unit layer 20 further includes: forming a first electrode layer 25 on the side of the first passivation layer 21 opposite to the first LED unit 22; the first electrode layer 25 surrounds the side of the first LED unit 22 and the side opposite to the first substrate 27; the first electrode layer 25 covers the surface of the first LED unit 22 on the side opposite to the first substrate 27 that is not covered by the first passivation layer 21; forming a planarization layer 23, which covers the first passivation layer 21 and the first electrode layer 25; forming a first conductive protrusion 24 and a conductive pillar 26; one end of the first conductive protrusion 24 is connected to the first electrode layer 25, and the other end extends vertically to the surface of the planarization layer 23 on the side opposite to the first substrate 27; the conductive pillar 26 penetrates vertically through the planarization layer 23 and the first passivation layer 21.

[0203] Specifically, as shown in Figure 5, a metal layer can be formed by depositing material on the side of the first passivation layer 21 away from the first substrate 27. This metal layer can cover the surface of the area of ​​the first LED unit 22 away from the first substrate 27 that is not covered by the first passivation layer 21. The metal layer is processed by a photolithography patterning process to form a first electrode layer 25, so that the first electrode layer 25 surrounds the side of the first LED unit 22 and the side of the first LED unit 22 away from the first substrate 27.

[0204] As shown in Figure 6, after forming the first electrode layer 25, a material (e.g., silicon dioxide) is deposited on the surface of the first passivation layer 21 on the side opposite to the first substrate 27 to form a planarization layer 23, so that the planarization layer 23 covers the first passivation layer 21 and the first electrode layer 25. As shown in Figure 7, the planarization layer 23 corresponding to the first electrode layer 25 is etched, and the planarization layer 23 and the first passivation layer 21 corresponding to the conductive pillar 26 are also etched to form multiple vias (G2 in Figure 7 is used to illustrate vias), preparing the structure for the formation of the first conductive bump 24 and the conductive pillar 26. As shown in Figure 8, the multiple vias are filled with a material (e.g., copper). The method of filling the material is not limited; for example, it can be done by deposition and electroplating (Cu Seed Deposition and Plating). As shown in Figure 9, after filling with material, part of the planarization layer 23 and part of the filling material are removed by chemical mechanical polishing (CMP) to obtain the first conductive bump 24, the conductive pillar 26 and the CMP-processed planarization layer 23. One end of the first conductive bump 24 is connected to the first electrode layer 25, and the other end of the first conductive bump 24 extends vertically to the surface of the CMP-processed planarization layer 23 on the side away from the first substrate 27. The conductive pillar 26 penetrates vertically through the first passivation layer 21 and the CMP-processed planarization layer 23.

[0205] Referring to Figures 2 to 9 and Figure 27, in one possible implementation, a method for fabricating a first LED unit layer 20 is provided, comprising:

[0206] S271. A first substrate is provided, on which a first LED epitaxial layer is disposed.

[0207] S272, Etch the first LED epitaxial layer to form multiple first LED units.

[0208] S273. A first passivation layer is formed, which covers the surface of the etched first LED epitaxial layer and exposes a portion of the surface of the plurality of first LED units on the side away from the first substrate.

[0209] S274. A first electrode layer is formed on the side of the first passivation layer away from the first LED unit. The first electrode layer surrounds the side of the first LED unit and the side away from the first substrate. The first electrode layer also covers the surface of the area of ​​the first LED unit away from the first substrate that is not covered by the first passivation layer.

[0210] S275. A planarization layer is formed, which covers the first passivation layer and the first electrode layer.

[0211] S276. A first conductive bump and a conductive pillar are formed. One end of the first conductive bump is connected to the first electrode layer, and the other end extends vertically to the surface of the planarization layer away from the first substrate. The conductive pillar penetrates the planarization layer and the first passivation layer vertically.

[0212] The implementation methods and technical effects of each step and each structure in the method for preparing the first LED unit layer 20 are described in the foregoing embodiments and will not be repeated here.

[0213] In some embodiments, as shown in Figures 18 and 19, the step of bonding the first LED unit layer 20 to the substrate 10 includes: bonding the planarization layer 23 to the substrate 10, and bonding and electrically connecting the first conductive protrusion 24 and the conductive pillar 26 to the corresponding first contact 11. The first substrate 27 and a portion of the first LED epitaxial layer 28 are removed until the surface of the first passivation layer 21 is exposed, making the surfaces of the first passivation layer 21, the first LED unit 22, and the conductive pillar 26 flush with the side facing away from the substrate 10.

[0214] As shown in Figure 18, the first hybrid bonding is achieved by bonding the planarization layer 23 to the substrate 10, and by bonding and electrically connecting the first conductive protrusion 24 and the conductive pillar 26 to the corresponding first contact 11. This simplifies the processing, reduces the processing difficulty, improves the overall yield, and reduces the size of the display 1.

[0215] Referring to Figures 18 and 19, the first substrate 27 and part of the first LED epitaxial layer 28 can be removed by chemical mechanical polishing (CMP) until the surface of the first passivation layer 21 is exposed, so that the surfaces of the first passivation layer 21, the first LED unit 22 and the conductive pillar 26 on the side away from the substrate 10 are flush, in preparation for the second LED unit layer 30 to be bonded to the first LED unit layer 20.

[0216] During CMP processing, the first passivation layer 21 is used as the processing reference. That is, processing stops when the surface of the first passivation layer 21 is exposed. This reduces the processing difficulty and cost, avoids or reduces the situation of device damage due to over-processing, and effectively protects the first LED unit 22 during processing, thereby improving the overall yield.

[0217] Referring to Figures 10 to 17 and Figure 28, in some embodiments, a method for fabricating a second LED unit layer 30 is provided, comprising:

[0218] S281. A second substrate is provided, on which a second LED epitaxial layer is disposed.

[0219] As shown in Figure 10, the second substrate 36 provides support, making the entire structure of the second LED unit layer 30 more stable. For example, a second LED epitaxial layer 37 can be grown on the second substrate 36, so that the second substrate 36 provides stable support for the growth of the second LED epitaxial layer 37.

[0220] It should be noted that the material of the second substrate 36 is not limited; for example, it can be silicon, sapphire, or gallium nitride. The material of the second LED epitaxial layer 37 is not limited; for example, it can be gallium nitride (GaN).

[0221] S282, Etch the second LED epitaxial layer to form multiple second LED units.

[0222] As shown in Figure 11, by etching the side of the second LED epitaxial layer 37 away from the second substrate 36, multiple mesa structures (MESAs) are formed on the second LED epitaxial layer 37. Each mesa structure can form a complete second LED unit 31, so that the second LED unit 31 can be independently driven and emit light by the substrate 10. Specifically, the multiple second LED units 31 are arranged at intervals.

[0223] S283. A second passivation layer is formed, which covers the surface of the etched second LED epitaxial layer and exposes a portion of the surface of the plurality of second LED units on the side away from the second substrate.

[0224] As shown in Figure 12, a second passivation layer 33 can be formed on the surface of the second LED epitaxial layer 37 away from the second substrate 36 by depositing a material (e.g., alumina or silicon dioxide), so that the second passivation layer 33 covers the surface of the second LED epitaxial layer 37 away from the second substrate 36 and the surfaces of the plurality of second LED units 31.

[0225] The second passivation layer 33 is etched to form multiple windows. G3 in Figure 12 is used to illustrate the windows formed by etching the second passivation layer 33. The multiple windows expose a portion of the surface of the multiple second LED units 31 on the side opposite to the second substrate 36, which prepares the structure for the subsequent electrical connection between the second LED units 31 and the second electrode layer 34.

[0226] S284. A second electrode layer is formed on the side of the second passivation layer away from the second LED unit. The second electrode layer surrounds the side of the second LED unit and the side away from the second substrate. The second electrode layer covers the surface of the area of ​​the second LED unit away from the second substrate that is not covered by the second passivation layer.

[0227] Referring to Figure 13, a metal layer is formed by depositing material on the side of the second passivation layer 33 facing away from the second substrate 36. This metal layer can cover the surface of the second LED unit 31 on the side facing away from the second substrate 36 and not covered by the second passivation layer 33. The metal layer is processed by a photolithography patterning process to form a second electrode layer 34, so that the second electrode layer 34 surrounds the side of the second LED unit 31 and the side of the second LED unit 31 facing away from the second substrate 36.

[0228] S285, A fill layer is formed, which covers the second passivation layer and the second electrode layer.

[0229] As shown in Figure 14, after forming the second electrode layer 34, a material (e.g., silicon dioxide) is deposited on the surface of the second passivation layer 33 on the side opposite to the second substrate 36 to form a fill layer 32, so that the fill layer 32 covers the second passivation layer 33 and the second electrode layer 34.

[0230] S286. A second conductive protrusion is formed in the filler layer. One end of the second conductive protrusion is electrically connected to the second electrode layer, and the other end extends vertically to the surface of the filler layer on the side away from the second substrate.

[0231] Referring to Figure 15, the etched fill layer 32 forms multiple vias, preparing the structure for the formation of the second conductive bump 35. G4 in Figure 15 is used to etch the vias formed by the fill layer 32. As shown in Figure 16, the vias are filled with a material (e.g., copper). The method of filling the material is not limited; for example, it can be done by deposition and electroplating (Cu Seed Deposition and Plating). As shown in Figure 17, after filling the material, part of the fill layer 32 and part of the fill material are removed by chemical mechanical polishing (CMP) to obtain the second conductive bump 35 and the CMP-processed fill layer 32. One end of the second conductive bump 35 is connected to the second electrode layer 34, and the other end of the second conductive bump 35 extends vertically to the surface of the CMP-processed fill layer 32 on the side opposite to the first substrate 27.

[0232] In some embodiments, as shown in Figures 20 and 21, the micro LED display 1 further includes conductive pillars 26. The step of bonding the second LED unit layer 30 to the first LED unit layer 20 includes: bonding the leveling layer 32 to the first passivation layer 21, and bonding and electrically connecting the second conductive protrusion 35 to the end of the conductive pillar 26 facing away from the substrate 10. The second substrate 36 and a portion of the second LED epitaxial layer 37 are removed until the surface of the second passivation layer 33 is exposed, making the surfaces of the second passivation layer 33 and the side of the second LED unit 31 facing away from the substrate 10 flush.

[0233] As shown in Figure 20, a second hybrid bonding is achieved by bonding the filler layer 32 to the first passivation layer 21 and bonding and electrically connecting the second conductive protrusion 35 to the end of the conductive pillar 26 away from the substrate 10. This simplifies the processing, reduces the processing difficulty, improves the overall yield, and reduces the size of the display 1.

[0234] As shown in Figure 21, the second substrate 36 and part of the second LED epitaxial layer 37 can be removed by chemical mechanical polishing (CMP) until the surface of the second passivation layer 33 is exposed, so that the surfaces of the second passivation layer 33 and the second LED unit 31 on the side away from the substrate 10 are flush, providing structural preparation for the subsequent formation of the common electrode layer 40.

[0235] During CMP processing, the second passivation layer 33 is used as the processing reference. That is, processing stops when the surface of the second passivation layer 33 is exposed. This reduces the processing difficulty and cost, avoids or reduces the situation of device damage due to over-processing, and effectively protects the second LED unit 31 during processing, thereby improving the overall yield.

[0236] In some embodiments, as shown in FIG22, after the step of bonding the second LED unit layer 30 to the first LED unit layer 20, the fabrication method further includes: etching the second LED unit layer 30 to expose the surface of the first LED unit 22 facing away from the substrate 10; forming a common electrode layer 40, the common electrode layer 40 at least covering the surfaces of the first LED unit 22 and the second LED unit 31 facing away from the substrate 10, and the common electrode layer 40 being electrically connected to the second contact of the substrate 10.

[0237] As shown in Figure 22, by etching the second LED unit layer 30, multiple windows are formed in the second LED unit layer 30, and each window exposes the surface of a plurality of first LED units 22 on the side facing away from the substrate 10. A material (such as ITO) is deposited on the surface of the second LED unit layer 30 on the side facing away from the substrate 10 and at the multiple windows of the second LED unit layer 30 to form a common electrode layer 40. This ensures that the common electrode layer 40 at least covers the surfaces of the plurality of first LED units 22 and the plurality of second LED units 31 on the side facing away from the substrate 10, and electrically connects the common electrode layer 40 to the second contacts of the substrate 10.

[0238] It is understood that the specific connection method between the common electrode layer 40 and the second contact of the substrate 10 is not limited, as long as it can achieve electrical connection between the common electrode layer 40 and the second contact of the substrate 10.

[0239] Referring to Figures 2 to 22 and Figure 29, in one possible implementation, a method for fabricating a miniature light-emitting diode display 1 is provided, comprising the following steps:

[0240] S291, Provide a substrate.

[0241] S292. Prepare a first LED unit layer, the first LED unit layer including a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on the surface of the first LED unit layer away from the substrate and exposes the surface of the plurality of first LED units away from the substrate; and the first passivation layer also covers at least the side surfaces of the plurality of first LED units.

[0242] S293. Bond the first LED unit layer to the substrate.

[0243] S294. Prepare a second LED unit layer, the second LED unit layer comprising a plurality of second LED units arranged at intervals and a filling layer located between adjacent second LED units.

[0244] S295. The second LED unit layer is bonded to the first LED unit layer, wherein the leveling layer is bonded to the first passivation layer. The plurality of first LED units and the plurality of second LED units are electrically connected to the substrate respectively, enabling individual driving.

[0245] S296. Etch the second LED unit layer to expose the surface of the first LED unit on the side away from the substrate.

[0246] S297. A common electrode layer is formed, which at least covers the surface of the first LED unit and the second LED unit on the side away from the substrate, and the common electrode layer is electrically connected to the second contact of the substrate.

[0247] The implementation methods and technical effects of each step and structure in the preparation method of this embodiment are the same as those in the foregoing embodiments, and will not be repeated here.

[0248] In some embodiments, as shown in Figures 1, 23, and 24, the fabrication method further includes: forming a protective layer 41, which at least covers the common electrode layer 40; and forming a color conversion unit 42 on the protective layer 41, which is located on a portion of the first LED unit 22 or a portion of the second LED unit 31.

[0249] Referring to Figure 23, a material (e.g., polyimide) is coated (e.g., spin-coated) on the side of the common electrode layer 40 away from the substrate 10 to form a protective layer 41, such that the protective layer 41 at least covers the common electrode layer 40.

[0250] Referring to Figure 24, a protective layer 41 is etched to form multiple windows, providing structural preparation for the formation of color conversion units 42. G5 in Figure 24 illustrates the windows formed by etching the protective layer 41. Referring to Figure 1, a material (e.g., quantum dot photoresist, QDPR) is filled at the multiple windows of the protective layer 41 to form multiple color conversion units 42. These multiple color conversion units 42 are positioned above a portion of the multiple first LED units 22, or above a portion of the multiple second LED units 31. Alternatively, some of the multiple color conversion units 42 are positioned above a portion of the multiple first LED units 22, and another portion are positioned above a portion of the multiple second LED units 31.

[0251] Referring to Figures 1 to 24 and Figure 30, in one possible implementation, a method for fabricating a miniature light-emitting diode display 1 is provided, comprising the following steps:

[0252] S301. Provide substrate.

[0253] S302. Prepare a first LED unit layer, the first LED unit layer including a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on the surface of the first LED unit layer away from the substrate and exposes the surface of the plurality of first LED units away from the substrate; and the first passivation layer also covers at least the side surfaces of the plurality of first LED units.

[0254] S303. Bond the first LED unit layer to the substrate.

[0255] S304. Prepare a second LED unit layer, the second LED unit layer including a plurality of second LED units arranged at intervals and a filling layer located between adjacent second LED units.

[0256] S305. The second LED unit layer is bonded to the first LED unit layer, wherein the filler layer is bonded to the first passivation layer.

[0257] In this embodiment, multiple first LED units 22 and multiple second LED units 31 are electrically connected to the substrate 10 to achieve individual driving.

[0258] S306. Etch the second LED unit layer to expose the surface of the first LED unit on the side away from the substrate.

[0259] S307. A common electrode layer is formed, which at least covers the surface of the first LED unit and the second LED unit on the side away from the substrate, and the common electrode layer is electrically connected to the second contact of the substrate.

[0260] S308. Form a protective layer, which at least covers the common electrode layer.

[0261] S309. A color conversion unit is formed in the protective layer, and the color conversion unit is located above a portion of the first LED unit or a portion of the second LED unit.

[0262] The implementation methods and technical effects of each step and structure in the preparation method of this embodiment are the same as those in the foregoing embodiments, and will not be repeated here.

[0263] It should be noted that the order in which the steps involved in the preparation method of this application are executed is not limited. For example, steps S302 and S304 can be executed in essentially parallel. Furthermore, step S304 can be executed before step S303.

[0264] This application also provides a display device. The display device includes a miniature light-emitting diode display 1 as described in any of the preceding embodiments. Therefore, the display device has the beneficial effects of the miniature light-emitting diode display 1 as described in any of the preceding embodiments, which will not be described in detail hereafter.

[0265] It should be noted that the miniature light-emitting diode display 1 or display device can be applied to augmented reality (AR) display devices, virtual reality (VR) display devices, near-eye display (NED) devices, head-up display (HUD) devices, and other similar devices.

[0266] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A miniature light-emitting diode display, wherein, include: A substrate, the substrate including a plurality of first contacts; The first LED unit layer, bonded to the substrate, includes a first passivation layer and a plurality of first LED units arranged at intervals; The first passivation layer is located on the surface of the first LED unit layer facing away from the substrate, and exposes the surface of the plurality of first LED units facing away from the substrate; and the first passivation layer also covers at least the side surfaces of the plurality of first LED units. The first LED unit layer further includes a planarization layer and a first conductive protrusion. The planarization layer is disposed on the side of the first passivation layer facing the substrate and is bonded to the substrate. One end of the first conductive protrusion is electrically connected to the first LED unit, and the other end is electrically connected to the corresponding first contact bond. Multiple first LED units are electrically connected to the substrate to achieve individual driving.

2. The miniature light-emitting diode display according to claim 1, wherein, Also includes: The second LED unit layer, bonded to the first LED unit layer, includes a plurality of second LED units arranged at intervals and a filler layer located between adjacent second LED units, wherein the filler layer is bonded to the first passivation layer; Multiple second LED units are electrically connected to the substrate to enable individual driving.

3. The miniature light-emitting diode display according to claim 2, wherein, The first LED unit layer further includes: The first electrode layer is disposed on the side of the first passivation layer away from the first LED unit, and surrounds the side of the first LED unit and the side facing the substrate. Furthermore, the first electrode layer covers the surface of the first LED unit on the side facing the substrate and not covered by the first passivation layer, and the first electrode layer reflects the light emitted by the first LED unit.

4. The miniature light-emitting diode display according to claim 2, wherein, The second LED unit layer also includes: The second passivation layer is disposed on the surface of the leveling layer opposite to the substrate and exposes the surface of the plurality of second LED units opposite to the substrate; and the second passivation layer also covers at least the side surfaces of the plurality of second LED units.

5. The miniature light-emitting diode display according to claim 4, wherein, The second LED unit layer also includes: The second electrode layer is disposed on the side of the second passivation layer away from the second LED unit, and surrounds the side of the second LED unit and the side facing the substrate; Furthermore, the second electrode layer covers the surface of the second LED unit facing the substrate and located where it is not covered by the second passivation layer, and the second electrode layer reflects the light emitted by the second LED unit.

6. The miniature light-emitting diode display according to claim 2, wherein, Also includes: A conductive post extends vertically through the first LED unit layer. One end of the conductive post is electrically connected to the substrate, and the other end of the conductive post is electrically connected to the corresponding second LED unit.

7. The miniature light-emitting diode display according to claim 6, wherein, The second LED unit layer also includes: The second conductive protrusion is electrically connected to the second LED unit; The conductive post is electrically connected to the second LED unit through the second conductive protrusion.

8. The miniature light-emitting diode display according to claim 2, wherein, The first LED unit and the second LED unit respectively include a first doped semiconductor layer, an active layer and a second doped semiconductor layer stacked together, with the first doped semiconductor layer close to the substrate; The surface of the second doped semiconductor layer of the first LED unit facing away from the substrate is flush with the surface of the first passivation layer facing away from the substrate.

9. The miniature light-emitting diode display according to claim 2, wherein, The substrate includes at least one second contact, and the micro LED display further includes: A common electrode layer is electrically connected to the surface of the first LED unit and the second LED unit on the side opposite to the substrate, and the common electrode layer is also electrically connected to the second contact.

10. The miniature light-emitting diode display according to claim 2, wherein, Also includes: Multiple color conversion units are located on a portion of the first LED unit or a portion of the second LED unit. The color conversion units are used to convert a first color light emitted by the first LED unit or a second color light emitted by the second LED unit into a third color light. The first color light, the second color light, and the third color light are different. In this configuration, at least one first LED unit, together with at least one adjacent second LED unit and at least one adjacent color conversion unit, constitute a full-color pixel.

11. The miniature light-emitting diode display according to claim 2, wherein, Also includes: The third LED unit layer, bonded to the second LED unit layer, includes a plurality of third LED units arranged at intervals, wherein the vertical projections of the first LED unit, the second LED unit, and the third LED unit on the substrate do not overlap; In this configuration, at least one first LED unit, together with at least one adjacent second LED unit and at least one adjacent third LED unit, constitute a full-color pixel.

12. A method for fabricating a miniature light-emitting diode display, wherein, Includes the following steps: A substrate is provided, the substrate including a plurality of first contacts; A first LED unit layer is prepared, the first LED unit layer comprising a first passivation layer and a plurality of first LED units arranged at intervals; The first passivation layer is located on the surface of the first LED unit layer facing away from the substrate, and exposes the surface of a plurality of first LED units facing away from the substrate; and the first passivation layer also covers at least the side surfaces of a plurality of first LED units; the first LED unit layer further includes a planarization layer and a first conductive protrusion, the planarization layer being disposed on the side of the first passivation layer facing the substrate; the first conductive protrusion being disposed on the planarization layer, and one end of the first conductive protrusion being electrically connected to the first LED unit; The first LED unit layer is bonded to the substrate, wherein the planarization layer is bonded to the substrate, and the first conductive protrusion is electrically connected to the corresponding first contact bond. In this embodiment, multiple first LED units are electrically connected to the substrate to achieve individual driving.

13. The preparation method according to claim 12, wherein, After the step of bonding the first LED unit layer to the substrate, the fabrication method further includes: A second LED unit layer is prepared, the second LED unit layer comprising a plurality of second LED units arranged at intervals and a filler layer located between adjacent second LED units; The second LED unit layer is bonded to the first LED unit layer, wherein the filler layer is bonded to the first passivation layer; In this embodiment, multiple second LED units are electrically connected to the substrate to achieve individual driving.

14. The preparation method according to claim 13, wherein, The steps for fabricating the first LED unit layer include: A first substrate is provided, on which a first LED epitaxial layer is disposed; The epitaxial layer of the first LED is etched to form multiple first LED units; A first passivation layer is formed, which covers the surface of the etched first LED epitaxial layer and exposes a portion of the surface of a plurality of first LED units on the side opposite to the first substrate.

15. The preparation method according to claim 14, wherein, The steps for fabricating the first LED unit layer also include: A first electrode layer is formed on the side of the first passivation layer away from the first LED unit. The first electrode layer surrounds the side of the first LED unit and the side away from the first substrate. The first electrode layer also covers the surface of the area of ​​the first LED unit away from the first substrate that is not covered by the first passivation layer. A planarization layer is formed, which covers the first passivation layer and the first electrode layer; A first conductive bump and a conductive pillar are formed. One end of the first conductive bump is connected to the first electrode layer, and the other end extends vertically to the surface of the planarization layer opposite to the first substrate. The conductive pillar penetrates the planarization layer and the first passivation layer vertically.

16. The preparation method according to claim 15, wherein, In the step of bonding the first LED unit layer to the substrate, the conductive post is electrically connected to the corresponding first contact point. The first substrate and part of the first LED epitaxial layer are removed until the surface of the first passivation layer is exposed, so that the surfaces of the first passivation layer, the first LED unit, and the conductive pillar on the side away from the substrate are flush.

17. The preparation method according to claim 13, wherein, The steps for fabricating the second LED unit layer include: A second substrate is provided, on which a second LED epitaxial layer is disposed; The epitaxial layer of the second LED is etched to form multiple second LED units; A second passivation layer is formed, which covers the surface of the etched second LED epitaxial layer and exposes a portion of the surface of a plurality of second LED units on the side opposite to the second substrate; A second electrode layer is formed on the side of the second passivation layer away from the second LED unit. The second electrode layer surrounds the side of the second LED unit and the side away from the second substrate. The second electrode layer covers the surface of the area of ​​the second LED unit away from the second substrate that is not covered by the second passivation layer. A filler layer is formed, which covers the second passivation layer and the second electrode layer; A second conductive protrusion is formed in the filler layer. One end of the second conductive protrusion is electrically connected to the second electrode layer, and the other end extends vertically to the surface of the filler layer on the side opposite to the second substrate.

18. The preparation method according to claim 17, wherein, The micro LED display also includes conductive pillars, and the step of bonding the second LED unit layer to the first LED unit layer includes: The filler layer is bonded to the first passivation layer, and the second conductive protrusion is bonded to and electrically connected to the end of the conductive post facing away from the substrate. Remove the second substrate and part of the second LED epitaxial layer until the surface of the second passivation layer is exposed, so that the surfaces of the second passivation layer and the second LED unit on the side away from the substrate are flush.

19. The preparation method according to claim 13, wherein, After the step of bonding the second LED unit layer to the first LED unit layer, the fabrication method further includes: The second LED unit layer is etched to expose the surface of the first LED unit facing away from the substrate; A common electrode layer is formed, which at least covers the surface of the first LED unit and the second LED unit on the side opposite to the substrate, and the common electrode layer is electrically connected to the second contact of the substrate.

20. The preparation method according to claim 19, wherein, Also includes: A protective layer is formed, which at least covers the common electrode layer; A color conversion unit is formed in the protective layer, and the color conversion unit is located above a portion of the first LED unit or a portion of the second LED unit.

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