Anti-crosstalk micro-display light-emitting pixel and manufacturing method thereof

Abstract

The invention discloses an anti-crosstalk micro-display light-emitting pixel and a manufacturing method thereof, and relates to the technical field of semiconductors. The micro-display light-emitting pixel includes: a driving backplane; the display module is arranged on the driving back plate, the display module comprises a light-emitting unit and a groove structure, the light-emitting unit is conducted with an anode contact in the driving back plate, the groove structure surrounds the light-emitting unit and penetrates through a vertical area where the display module is located, and the display module is arranged on the driving back plate. The trench structure is filled with a metal material, and the light-emitting unit is an inorganic compound semiconductor. Based on the technical scheme provided by the invention, light emitting constraint can be carried out through the through type groove structure, and better optical crosstalk isolation is realized.

Description

[0001] This application claims priority to Chinese patent application No. 202311840767.0 filed on December 29, 2023, entitled “Anti-crosstalk micro-display luminous pixels and manufacturing method thereof, micro-display screen”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of semiconductor technology, and in particular to a crosstalk-proof micro-display luminous pixel and a manufacturing method thereof. Background Art

[0003] In the field of semiconductor technology, crosstalk and light distribution between micro-display light-emitting pixels have a significant impact on display quality and the efficiency of coupling into optical waveguides. For example, the light-emitting angle of a normal vertically structured light-emitting diode (LED) chip is around ±55°.

[0004] In the related art, the technical solutions of black matrix (BM) between pixels or making microlenses (MicroLens) are mostly used to achieve the constraints of crosstalk and luminous distribution between micro-display luminous pixels. In the black matrix solution, the black matrix is ​​an organic material system, which has insufficient temperature resistance and mechanical strength, and has reliability defects. In addition, the black matrix absorbs light, which will cause overall brightness loss. In the microlens solution, the prepared microlens belongs to the organic material system, which has insufficient temperature resistance and mechanical strength, and has reliability defects. In addition, complete optical isolation cannot be achieved between pixels. When the pixel size continues to shrink, the emission angle of ±55° will appear before entering the microlens, that is, the problem of crosstalk between adjacent pixels will occur.

[0005] Therefore, there is an urgent need to provide a new micro-display luminous pixel preparation solution that can avoid the above-mentioned defects. Summary of the invention

[0006] The object of the present invention is to provide a crosstalk-proof micro-display luminous pixel and a manufacturing method thereof, which can realize better optical crosstalk isolation by performing luminescence confinement through a through-type groove structure.

[0007] In order to achieve the above-mentioned object of the invention, the present invention proposes the following technical solutions:

[0008] On the one hand, a crosstalk-proof micro-display luminous pixel is provided, wherein the size of the micro-display luminous pixel is in the range of 0.5 um to 50 um, and the micro-display luminous pixel comprises:

[0009] Driver backplane;

[0010] A display module is provided on the driving backplane, the display module includes a light-emitting unit and a groove structure, the light-emitting unit is connected to the anode contact in the driving backplane, the groove structure surrounds the light-emitting unit and penetrates the vertical area where the display module is located, the groove structure is filled with metal material, and the light-emitting unit is an inorganic compound semiconductor.

[0011] In an optional implementation, the display module at least includes: a first display device layer; the first display device layer includes:

[0012] A first light-emitting unit, wherein a first P-type ohmic contact layer in the first light-emitting unit is connected with a through hole, and the first light-emitting unit is electrically connected to an anode contact in the driving backplane through the through hole filled with a metal material;

[0013] A first insulating layer, wherein the first insulating layer is filled and formed outside the first light emitting unit;

[0014] A first groove structure, wherein the first groove structure penetrates the first insulating layer, one end of the first groove structure is connected to the first N-type ohmic contact layer in the first light-emitting unit, and the other end is connected to the upper surface of the driving backplane.

[0015] In an optional implementation, the display module further includes: a second display device layer disposed on the first display device layer; the second display device layer includes:

[0016] A second insulating layer, the second insulating layer is filled and formed on a side of the first display device layer away from the driving backplane;

[0017] A second trench structure, wherein the second trench structure penetrates the second insulating layer and the first N-type ohmic contact layer, and one end of the second trench structure is connected to the first trench structure.

[0018] In an optional implementation, the width of the second trench structure is smaller than the width of the first trench structure.

[0019] In an optional implementation, the display module at least includes: a third display device layer; the third display device layer includes:

[0020] A second light-emitting unit, wherein a bonding layer is provided between the second P-type ohmic contact layer in the second light-emitting unit and the driving backplane, the second light-emitting unit is electrically connected to the anode contact in the driving backplane through the bonding layer, and a surface of the second N-type ohmic contact layer in the second light-emitting unit is covered with a portion of a cathode layer;

[0021] a third insulating layer, the third insulating layer being filled and formed outside the second light emitting unit;

[0022] A third trench structure is provided, wherein the third trench structure penetrates the third insulating layer, and one end of the third trench structure is connected to the cathode layer.

[0023] In an optional embodiment, the cathode layer includes: a middle cathode layer and side cathode layers on both sides, and the middle cathode layer is covered on the surface of the second N-type ohmic contact layer;

[0024] The side wall of the second light emitting unit and the surface of the driving backplane are covered with a passivation layer, and the side cathode layer is covered on the surface of the passivation layer;

[0025] or,

[0026] The side cathode layer is covered on a surface of the third insulating layer which is away from the driving back plate.

[0027] In an optional embodiment, when the side cathode layer is covered on a surface of the third insulating layer away from the driving backplane, the side wall of the second light-emitting unit and the surface of the driving backplane are further covered with a passivation layer.

[0028] In an optional implementation, the groove structure is located inside the display module;

[0029] or,

[0030] The groove structure is located at the outer periphery of the display module.

[0031] In an optional embodiment, the groove pattern corresponding to the groove structure in a top view includes:

[0032] One of circle, rectangle, hexagon and octagon.

[0033] In an optional implementation, the display module further includes: a micro lens;

[0034] The microlens is arranged on the light emitting unit and the groove structure.

[0035] In an optional implementation, the metal material filled in the groove structure includes:

[0036] Aluminum, nickel, vanadium, and copper are deposited vertically in sequence;

[0037] or, deposited aluminum;

[0038] or, deposited tungsten.

[0039] In a possible implementation manner, the overall depth of the groove structure is not less than the overall depth of the light emitting unit.

[0040] In a possible implementation, the width of the trench structure is in the range of 90 nm to 5 um.

[0041] In a possible implementation manner, the depth of the groove structure is in the range of 0.4 um to 5 um.

[0042] In a possible implementation manner, the angle of the groove structure gradually increases in a direction away from the driving back plate.

[0043] On the other hand, a method for preparing a micro-display luminous pixel is provided, the method being used to prepare the micro-display luminous pixel as described in the above aspect, the method comprising:

[0044] preparing a drive backplane;

[0045] A display module combined with the driving backplane is prepared, wherein the display module includes a light-emitting unit and a groove structure, wherein the light-emitting unit is electrically connected to an anode contact in the driving backplane, the groove structure surrounds the light-emitting unit and penetrates a vertical region where the display module is located, the groove structure is filled with a metal material, and the light-emitting unit is an inorganic compound semiconductor.

[0046] In an optional embodiment, the preparation of the display module combined with the driving backplane includes:

[0047] Performing step etching on the inorganic compound semiconductor to prepare a first light-emitting unit;

[0048] Using an insulating material to perform step filling on the first light-emitting unit to form a first insulating layer;

[0049] Etching the first insulating layer to form a through hole connected to the first P-type ohmic contact layer in the first light-emitting unit and a first groove structure surrounding the first light-emitting unit;

[0050] Filling the through hole and the first groove structure with metal material, and combining the first light-emitting unit, the first insulating layer, and the first groove structure into a first display device layer;

[0051] The first display device layer is combined with the driving backplane through a hybrid bonding process, and during the combination, the first light-emitting unit is connected to the anode contact in the driving backplane through the through hole filled with metal material.

[0052] In an optional implementation, after combining the first display device layer with the driving backplane, the method further includes:

[0053] removing the compound substrate in the first light-emitting unit;

[0054] The surface of the first light-emitting unit is roughened after the substrate is removed.

[0055] In an optional implementation, after forming the first display device layer, the method further includes:

[0056] Filling the first display device layer with an insulating material to form a second insulating layer;

[0057] Etching the second insulating layer to form a second trench structure having one end connected to the first trench structure;

[0058] The second trench structure is filled with metal material, and the second insulating layer and the second trench structure are combined into a second display device layer.

[0059] In an optional embodiment, the preparation of the display module combined with the driving backplane includes:

[0060] The inorganic compound semiconductor prepared with a bonding layer and the driving backplane prepared with a bonding layer are combined by a hybrid bonding process, wherein the inorganic compound semiconductor is connected to the anode contact in the driving backplane through the bonding layer during the combination;

[0061] Performing step etching on the inorganic compound semiconductor and the bonding layer to prepare a second light-emitting unit;

[0062] The second light-emitting unit is step-filled with an insulating material to form a third insulating layer; the third insulating layer is etched to form a third groove structure surrounding the second light-emitting unit; the third groove structure is filled with a metal material; a portion of the third insulating layer on the top surface of the second light-emitting unit is removed by a patterning process to expose the second N-type ohmic contact layer in the second light-emitting unit; a cathode layer is covered on the surface of the second N-type ohmic contact layer and on the side of the third insulating layer away from the driving backplane;

[0063] or,

[0064] A passivation layer is covered on the surface of the second light-emitting unit and the surface of the driving backplane; a portion of the passivation layer on the top surface of the second light-emitting unit is removed by a graphic process to expose the second N-type ohmic contact layer in the second light-emitting unit; a cathode layer is covered on the surface of the second N-type ohmic contact layer and the surface of the passivation layer; the second light-emitting unit is step-filled with an insulating material to form a third insulating layer; the third insulating layer is etched to form a third groove structure surrounding the second light-emitting unit; and the third groove structure is filled with a metal material.

[0065] In an optional embodiment, in a method corresponding to covering a cathode layer on a surface of the second N-type ohmic contact layer and a surface of a side of the third insulating layer away from the driving backplane, before step-filling the second light-emitting unit with an insulating material to form the third insulating layer, the method further includes:

[0066] A passivation layer is provided on the surface of the second light emitting unit and the surface of the driving backplane.

[0067] In an optional embodiment, after preparing the display module combined with the driving backplane, the method further includes:

[0068] A microlens is prepared on the light emitting unit and the groove structure.

[0069] Compared with the prior art, the present invention has the following beneficial effects:

[0070] By etching a groove structure in the display module of the micro-display light-emitting pixels and filling the groove structure with metal material, better optical crosstalk isolation can be achieved through the through-type groove structure. The light-emitting angle can be customized by the depth of the groove structure. The design process of the groove structure is relatively mature, and mass production and yield are guaranteed.

[0071] Furthermore, the light-emitting unit and the groove structure in the display module belong to an inorganic material system, which has good temperature resistance and mechanical strength, and the reliability is guaranteed.

[0072] Furthermore, the invention provides a back side groove structure design idea, a back side groove structure design idea, and a front side and back side groove structure combined design idea, and different schemes can be freely selected according to needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 It is a schematic diagram of the optical crosstalk phenomenon corresponding to the related art;

[0074] Figure 2 is a schematic diagram of the structure of a micro-display luminous pixel provided in an embodiment of the present application;

[0075] Figure 3 is a circuit diagram of a driving circuit provided in an embodiment of the present application;

[0076] Figure 4 is a schematic diagram of the optical crosstalk phenomenon corresponding to the embodiment of the present application;

[0077] Figure 5 is a schematic diagram of the structure of a micro-display luminous pixel provided in an embodiment of the present application;

[0078] Figure 6 is a schematic diagram of a groove pattern provided in an embodiment of the present application;

[0079] Figure 7 This is a schematic diagram of the structure of a micro-display luminous pixel under a front groove structure design concept provided in an embodiment of the present application;

[0080] Figure 8 It is a schematic diagram of the structure of a micro-display luminous pixel with a micro-lens provided in an embodiment of the present application;

[0081] Fig. 9 It is a schematic diagram of the structure of a micro-display luminous pixel with a micro-lens provided in an embodiment of the present application;

[0082] Fig.10 This is a schematic diagram of the structure of a micro-display luminous pixel under a back groove structure design concept provided in an embodiment of the present application;

[0083] Fig.11 This is a schematic diagram of the structure of a micro-display luminous pixel under a back groove structure design concept provided in an embodiment of the present application;

[0084] Fig.12 This is a schematic diagram of the structure of a micro-display luminous pixel under a back groove structure design concept provided in an embodiment of the present application;

[0085] Fig.13 This is a schematic diagram of the structure of a micro-display luminous pixel under a back groove structure design concept provided in an embodiment of the present application;

[0086] Fig.14 is a schematic diagram of a light emission constraint provided in an embodiment of the present application;

[0087] Fig.15 is a schematic diagram of a light emission constraint provided in an embodiment of the present application;

[0088] Fig.16 It is a schematic diagram of the structure of a micro-display luminous pixel with a micro-lens provided in an embodiment of the present application;

[0089] Fig.17It is a schematic diagram of the structure of a micro-display luminous pixel with a micro-lens provided in an embodiment of the present application;

[0090] Fig.18 This is a schematic diagram of the structure of a micro-display luminous pixel in the embodiment of the present application in combination with a front and back groove structure design idea;

[0091] Fig.19 It is a schematic diagram of the structure of a micro-display luminous pixel with a micro-lens provided in an embodiment of the present application;

[0092] Fig. 20 is a method flow chart of a method for preparing a micro-display luminous pixel provided in an embodiment of the present application;

[0093] Fig.21 is a structural schematic diagram of a driving backplane provided in an embodiment of the present application;

[0094] Fig. 22 is a schematic structural diagram of an inorganic compound semiconductor provided in an embodiment of the present application;

[0095] Fig.23 is a schematic diagram of the structure of an inorganic compound semiconductor after step etching provided in an embodiment of the present application;

[0096] Fig.24 is a schematic structural diagram of an inorganic compound semiconductor after a groove structure is prepared according to an embodiment of the present application;

[0097] Fig.25 is a schematic structural diagram of a metal-filled inorganic compound semiconductor provided in an embodiment of the present application;

[0098] Fig.26 This is a schematic diagram of the structure of an inorganic compound semiconductor combined with a driving backplane provided in an embodiment of the present application;

[0099] Fig. 27 is a schematic structural diagram of a micro-display luminous pixel after surface roughening provided in an embodiment of the present application;

[0100] Fig.28 is a schematic diagram of the structure of an inorganic compound semiconductor after step etching provided in an embodiment of the present application;

[0101] Fig.29 is a schematic structural diagram of an inorganic compound semiconductor prepared with a bonding layer provided in an embodiment of the present application;

[0102] Fig.30 is a schematic structural diagram of a driving backplane prepared with a bonding layer provided in an embodiment of the present application;

[0103] Fig.31 This is a schematic diagram of the structure of an inorganic compound semiconductor combined with a driving backplane provided in an embodiment of the present application;

[0104] Fig.32 It is a schematic diagram of a structure after step etching of a bonding structure provided in an embodiment of the present application;

[0105] Fig.33 It is a schematic diagram of a structure in which a passivation layer and a cathode layer are covered on a second light-emitting unit provided in an embodiment of the present application;

[0106] Fig.34 is a schematic structural diagram of a bonding structure after step filling provided in an embodiment of the present application;

[0107] Fig.35 is a structural schematic diagram of a bonding structure after a groove structure is prepared provided in an embodiment of the present application;

[0108] Fig.36 is a schematic structural diagram of a bonding structure after step filling provided in an embodiment of the present application;

[0109] Fig.37 It is a structural schematic diagram of a bonding structure after a groove structure is prepared provided in an embodiment of the present application.

[0110] Reference numerals:

[0111] 10-driving backplane, 11-anode contact, 20-display module, 21-first display device layer, 22-second display device layer, 23-third display device layer, 30-light-emitting unit, 31-first light-emitting unit, 311-first P-type ohmic contact layer, 312-through hole, 313-first N-type ohmic contact layer, 316-first substrate, 317-first active quantum well layer, 32-second light-emitting unit, 321-second P-type ohmic contact layer Contact layer, 322-bonding layer, 323-second N-type ohmic contact layer, 324-second substrate, 325-second active quantum well layer, 40-groove structure, 41-first groove structure, 42-second groove structure, 43-third groove structure, 50-microlens, 61-first insulating layer, 62-second insulating layer, 63-third insulating layer, 70-cathode layer, 71-middle cathode layer, 72-side cathode layer, 80-passivation layer. DETAILED DESCRIPTION

[0112] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0113] In the description of the present invention, it should be understood that the terms "vertical", "upper", "lower", "top", "side", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0114] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0115] Traditional anti-crosstalk design solutions for micro-display luminous pixels have many defects, such as:

[0116] The anti-crosstalk design scheme for preparing microlenses uses an organic material system, which has insufficient temperature resistance and mechanical strength, reliability defects, and cannot achieve complete optical isolation between pixels. When the pixel size continues to shrink, when the luminous angle is ±55°, crosstalk between adjacent pixels will occur before entering the microlens. Figure 1As an example, take a GaN Micro LED vertical structure device with a 4um pixel size and a 2um light-emitting unit as an example. Its vertical structure has the smallest light-emitting angle of ±55° of conventional LED devices, which is lower than the light-emitting angle of ±60-70° of horizontal and flip-chip structure LED devices. When the light-emitting angle is ±55°, the optical crosstalk between adjacent pixels cannot be completely isolated, because the light emitted by the active light-emitting area will pass through the entire light-emitting unit to become a multi-faceted exit, and the actual light angle will be larger than Figure 1 It is more complicated because the light is refracted and reflected multiple times in the light-emitting unit, which causes more serious optical crosstalk between pixels.

[0117] For the anti-crosstalk design scheme using black matrix, the black matrix blocks light through the light absorption characteristics of the black matrix material to achieve optical crosstalk isolation between pixels. The black matrix is ​​an organic material system, which has insufficient temperature resistance and mechanical strength, and reliability defects. In addition, the black matrix absorbs light, which will lead to overall brightness loss. In some schemes, a trapezoidal structure similar to the black matrix is ​​formed by metal patterning deposition and gold tearing to avoid reliability issues. However, neither the black matrix nor the metal patterning gold tearing scheme can adapt to particularly small pixel sizes. For example, when the pixel size dives below 5um, the resolution of the black matrix and the photoresist mask peeling problem of metal patterning gold tearing will bring challenges to the yield and mass production capabilities.

[0118] In order to avoid the above problems, in an embodiment of the present application, a technical solution is proposed to achieve better optical crosstalk isolation by confining light emission through a through-type groove structure.

[0119] It can be understood that the groove structure in the embodiment of the present application is a technology applied in the field of micro-display (Micro-LED). The groove structure is prepared by using metal materials, and has the characteristics of optical crosstalk optimization, light-emitting angle convergence, electrical transmission function enhancement, high temperature resistance and other harsh environments. It is quite different from similar structures in traditional large panel displays.

[0120] On the one hand, similar structures in traditional large panel displays cannot be directly applied to the field of micro-display. For traditional large panel displays, such as CN110969952A, it is a typical traditional large panel display structure, LED is used as the backlight source, but because the spacing between the LED lamp beads is large, the image display has a strong sense of granularity, and the brightness distribution is extremely uneven, which makes the audience feel dazzling, so generally a hollow grid structure prepared by compression molding, printing, spraying, etc. is used. This hollow grid structure is placed around the LED to constrain the light-emitting range, and after the light is irradiated to the diffusion film, the light is evenly distributed through the diffusion film to achieve a relatively uniform display effect. The function of the hollow grid structure of this scheme can be used as a common pixel crosstalk isolation method, but after entering the field of micro-display, the preparation of the hollow grid and the alignment accuracy with the LED light source cannot be achieved, so other schemes are needed in the field of micro-display to achieve similar functions.

[0121] On the other hand, in the typical traditional large panel display structure shown in CN110969952A, although the light shielding frame can also play the role of optimizing optical crosstalk, compared with the groove structure in this patent application, the differences mainly include:

[0122] (1) The pixel pitch and pixel size in CN110969952A are generally large, basically in the order of hundreds of microns or even several millimeters, and the line width of the light shielding frame between pixels is not required to be high. The light shielding frame is mostly made of organic materials, such as black glue, and the temperature resistance is generally around 200°C or below; the groove structure in this application is used in the field of micro-display, and the pixel pitch and pixel size are generally in the order of microns to tens of microns, and the groove structure is made of metal material, which has very high temperature resistance;

[0123] (2) Due to the difference in the implementation materials, the shading frame in CN110969952A only has an optical function, while the groove structure in the present application also plays a role in enhancing the electrical transmission function and better expanding the current distribution. Its connection with the cathode or cathode-related connection of the light-emitting unit should form good contact and uniformly distribute the current.

[0124] Next, the specific structure of the micro-display luminous pixel proposed in this application is described.

[0125] The embodiment of the present application provides a crosstalk-proof micro-display luminous pixel (hereinafter referred to as micro-display luminous pixel), the size of which is in the range of 0.5um to 50um. Figure 2 As shown, the micro display luminous pixel includes:

[0126] A driving backplane 10; a display module 20, wherein the display module 20 is disposed on the driving backplane 10, and the display module 20 includes a light-emitting unit 30 and a groove structure 40, wherein the light-emitting unit 30 is electrically connected to an anode contact in the driving backplane 10, and the groove structure 40 surrounds the light-emitting unit 30 and penetrates a vertical region where the display module 20 is located, and wherein the groove structure 40 is filled with a metal material, and the light-emitting unit 30 is an inorganic compound semiconductor.

[0127] The driving backplane 10 is an active driving backplane that is a combination of one or more thin film transistors (TFT), low temperature polycrystalline silicon (LTPS), CMOS integrated circuits, high mobility transistors (HEMT), etc. Specifically, the driving backplane 10 is provided with a driving circuit, and the driving circuit is provided with at least one anode contact 11. For example, the circuit structure of the driving circuit is as follows: Figure 3 As shown. It should be noted that the driving circuit in this embodiment is an active drive, and the circuit diagram shown in this embodiment is only a simple schematic diagram. The driving circuit may include an active, passive or semi-passive control circuit. All anodes included in the driving circuit may be arranged linearly or in an array, and any anode contact 11 is located in the middle or at the edge of the driving backplane 10, which is not limited in this embodiment.

[0128] The display module 20 is designed with a through groove structure 40, which surrounds the light-emitting unit 30 in the display module 20 and is filled with metal material. The light-emitting unit 30 is an inorganic compound semiconductor. The entire display module 20 is a pure inorganic structure with high reliability. For example, Figure 4 As shown, the design of the trench structure 40 (ie, the TI structure in the figure) can constrain the light emission angle, thereby preventing optical crosstalk between adjacent micro-display light-emitting pixels.

[0129] Further, such as Figure 5 As shown, the display module 20 further includes: a microlens 50; the microlens 50 is arranged on the light-emitting unit 30 and the groove structure 40. The microlens 50 can be arranged on the top of the display module 20, and the basic light emission constraint is first performed through the groove structure 40, and then the microlens 50 is used to further isolate the light emitted by the light-emitting unit 30 from optical crosstalk. The material of the microlens 50 can be a compound semiconductor, and can be a dielectric material such as silicon oxide, silicon nitride, etc. that is subsequently deposited.

[0130] Further, the light-emitting unit 30 in the display module 20 is an inorganic compound semiconductor, usually a wafer or a suitable size area cut from a wafer. Taking a wafer as an example, the wafer refers to a compound formed by two or more elements with a determined atomic ratio, and has semiconductor properties such as a determined bandgap width and band structure. It can be specifically a crystalline inorganic compound (such as III-V group, II-VI group compound semiconductor), and then a layer for forming electrical contact is prepared on the surface of the compound, and when the compound is subsequently stacked, it can be arbitrarily combined. In this embodiment, the light-emitting unit 30 involves ultraviolet light, green light, blue light AlGaN, InGaN ternary material system, and its substrate material can be GaN, Si, SiC, Sapphire, etc., as well as long waves such as red light and infrared, where red light can be InGaN ternary material system or GaAs substrate quaternary AlGaInP red light compound LED epitaxy, infrared mainly includes InP, GaAs, AlGaAs and other material systems compound epitaxy. In addition, the embodiment does not limit the shape of the light emitting unit 30 in a top view, and may be a circle or other polygons, such as a rectangle, a hexagon, an octagon, etc. In addition, the etching depth of the light emitting unit 30 may be in the range of 0.3um to 3um.

[0131] In one embodiment, when the light emitting unit 30 includes a red light compound epitaxy, the red light compound epitaxy may be a quaternary AlGaInP or ternary InGaN material, and may be based on a substrate such as GaAs, Si, Sapphire, or Ga2O3. The following Table 1 is a simplified structural example, in which P-GaAs may be replaced by P-GaP and P-AlGaAs:

[0132] Table 1

[0133] Layer Name Material Layer Name Material P-type ohmic contact layer P-GaAs P-type ohmic contact layer P-GaN Active quantum well layer AIGaInP Active quantum well layer InGaN&GaN N-type ohmic contact layer N-GaAs N-type ohmic contact layer N-GaN Etch stop layer N-AIGaInP Etch stop layer AIN&GaN Substrate N-GaAs Substrate Si

[0134] In one embodiment, when the light emitting unit 30 includes a blue light or green light compound semiconductor, the blue light or green light compound semiconductor is an InGaN ternary compound, which can be based on a substrate such as Si, Sapphire, or Ga2O3. An example of its structure is shown in Table 2 below:

[0135] Table 2

[0136] Layer Name Material Layer Name Material P-type ohmic contact layer P-GaN P-type ohmic contact layer P-GaN Active quantum well layer InGaN&GaN Active quantum well layer InGaN&GaN N-type ohmic contact layer N-GaN N-type ohmic contact layer N-GaN Etch stop layer InGaN Etch stop layer AIN&GaN Substrate GaN Substrate Si

[0137] In one embodiment, when the light emitting unit 30 includes an ultraviolet compound semiconductor, the ultraviolet compound semiconductor is an AlGaN ternary compound, which can be based on a substrate such as Si, Sapphire, or SiC. An example of its structure is shown in Table 3 below:

[0138] Table 3

[0139] Layer Name Material Layer Name Material P-type ohmic contact layer P-GaN P-type ohmic contact layer P-GaN Active quantum well layer AIGaN&InGaN Active quantum well layer AIGaN&InGaN N-type ohmic contact layer N-GaN N-type ohmic contact layer N-GaN Buffer layer AIN&AIGaN Buffer layer AIN&GaN Substrate Si Substrate Sapphire

[0140] In one embodiment, when the light emitting unit 30 includes an infrared compound semiconductor, the infrared compound semiconductor is an AlGaAs ternary compound and can be based on a substrate such as GaAs or InP. An example of its structure is shown in Table 4 below:

[0141] Table 4

[0142]

[0143]

[0144] As shown in Tables 1 to 4 above, by selecting different compound materials to prepare devices, light-emitting components with different wavelengths can be obtained. Different materials are selected as P-type and N-type ohmic contact layer materials according to the characteristics of different compounds. For example, the P-type ohmic contact layer uses ITO transparent conductive film, and the N-type ohmic contact layer uses metal In+ITO transparent conductive film, which can be used as universal ohmic contact materials. In particular, the P-type ohmic contact layer of GaN can be a single layer or a stack of metals such as Ni, Au, Ag, Al, etc., and the N-type ohmic contact layer can be a single layer or a stack of metals such as Ti, Cr, Ni, Al, etc. The P-type ohmic contact layer of GaAs can be a single layer, alloy or stack of metals such as Au, Be, Zn, etc., and the N-type ohmic contact layer can be a single layer, alloy or stack of metals such as Au, Ge, Ni, Pt, In, etc.

[0145] Further, the metal material filled in the groove structure 40 includes: aluminum (Al), nickel vanadium (NiV), copper (Cu) deposited vertically in sequence; or, deposited aluminum; or, deposited tungsten (W). In the groove structure 40, the filled metal material can be Cu electroplated after plasma vapor deposition of seed layers Al and NiV, wherein Al can be used as a reflective metal to increase brightness, and Al can also be used as a step-etched N-type ohmic contact metal to the N-type ohmic contact layer to achieve N connection, NiV as an adhesion layer and barrier layer for adhering Al, Cu and blocking the migration of Al, and Cu is used for electroplating. Further, NiV can be replaced by any one of Ni, Ti, and TiN; the metal material can also be a metal directly deposited by plasma vapor at room temperature or thermally deposited, such as metal Al or metal W. Further, TIN metal deposition can be performed before Al or W deposition. It is understandable that, in addition to the above-mentioned types of metal materials, the seed layer in the groove structure 40 may also be a single layer or multiple layers of metals such as Ti, Ni, Cr, Au, Ge, Al, Pt, Ta, W, or their nitrides, and the present application does not specifically limit this. Furthermore, the corresponding groove pattern of the groove structure 40 when viewed from above includes: one of a circle, a rectangle, a hexagon, and an octagon. When looking down at the micro-display light-emitting pixel, the groove pattern surrounding the light-emitting unit may be a circle, a rectangle, a hexagon, an octagon, etc., and the present embodiment does not limit this.

[0146] Furthermore, the groove structures 40 corresponding to adjacent light-emitting units are interconnected; or, the groove structures 40 corresponding to adjacent light-emitting units are isolated from each other by an insulating medium. The groove structure 40 can be implemented as follows: Figure 6 The style of connecting pixels shown can also be achieved as Figure 6 The style inside the pixel shown, Figure 6 The circular and rectangular groove patterns are used as examples for illustrative description.

[0147] Furthermore, the overall depth of the groove structure 40 is not less than the overall depth of the light-emitting unit 30. When etching the groove structure, the etching depth corresponding to the groove structure 40 is greater than or equal to the etching depth corresponding to the light-emitting unit 30, so that the groove structure 40 can constrain the light-emitting angle of the light-emitting unit 30 through a sufficient depth. In addition, the depth of the groove structure is in the range of 0.4um to 5um.

[0148] Furthermore, the width of the groove structure 40 is in the range of 90 nm to 5 um. By designing the width of the groove structure 40 within a certain range, it is possible to avoid the groove structure 40 occupying too much horizontal space of the pixel while ensuring that the groove structure 40 has sufficient thickness to prevent crosstalk.

[0149] Furthermore, the angle of the groove structure 40 gradually increases in the direction away from the driving backplane 10. The groove structure 40 formed can be realized through multiple angles from bottom to top, such as through multiple angles that gradually increase in the direction away from the driving backplane 10, so as to first strictly constrain the luminous angle from the bottom, and then evenly emit light through the top. In addition, the groove structure 40 can also be realized from bottom to top at an angle. In addition, the above angle can be in the range of 90°±30°, with 90°±10° being optimal. In the present application, based on the difference in the order of the groove preparation process, three different specific structural design ideas for micro-display luminous pixels are provided.

[0150] (1) The micro-display luminous pixel adopts a front groove structure design concept. In the preparation process corresponding to this structural design, the groove structure 40 is first prepared in the display module 20, and then the display module 20 is combined with the driving backplane 10.

[0151] Specifically, Figure 7 As shown, the display module 20 at least includes: a first display device layer 21; the first display device layer 21 includes: a first light-emitting unit 31, a first P-type ohmic contact layer 311 in the first light-emitting unit 31 is connected with a through hole 312, and the first light-emitting unit 31 is connected to the anode contact in the driving backplane 10 through the through hole 312 filled with metal material; a first insulating layer 61, the first insulating layer 61 is filled and formed outside the first light-emitting unit 31; a first groove structure 41, the first groove structure 41 runs through the first insulating layer 61, one end of the first groove structure 41 is connected to the first N-type ohmic contact layer 313 in the first light-emitting unit 31, and the other end is connected to the upper surface of the driving backplane 10, extending from the plane to the periphery of the display area and connected to the periphery of the driving backplane 10 Common cathode. Among them, the metal material filled in the through hole 312 can be the same as or different from the metal material filled in the first groove structure 41, such as using the same deposited Al, NiV, Cu. The first insulating layer 61 may be a single layer or a stack of dielectric layers such as silicon oxide, silicon nitride, SIC, SICN, Ti3O5, Ni2O5, etc. The thickness of the first insulating layer 61 and the depth of the first trench structure 41 are generally substantially equal to the thickness of the first light emitting unit 31, and the depth of the first trench structure 41 is limited by the thickness of the first light emitting unit 31.

[0152] Further, such as Figure 8 , Fig. 9 As shown, a micro lens 50 may be disposed on the first display device layer 21. In view of the design idea of ​​the front groove structure, in one embodiment, as Figure 8 As shown, the first N-type ohmic contact layer 313 is not cut off during the etching of the microlens 50. In another embodiment, as shown in FIG. Fig. 9As shown, when etching the microlens 50, part of the first N-type ohmic contact layer 313 is cut off, and while the N-type contact conduction cathode is realized in a part of the area, the micro display light-emitting pixels are completely isolated from each other.

[0153] (2) The micro-display luminous pixel adopts a back-side groove structure design concept. In the preparation process corresponding to this structural design, the display module 20 is first combined with the driving backplane 10, and then the groove structure 40 is prepared in the display module 20.

[0154] Specifically, Figures 10 to 13 As shown, the display module 20 at least includes: a third display device layer 23; the third display device layer 23 includes: a second light-emitting unit 32, a bonding layer 322 is provided between the second P-type ohmic contact layer 321 in the second light-emitting unit 32 and the driving backplane 10, the second light-emitting unit 32 is connected to the anode contact in the driving backplane 10 through the bonding layer 322, and the surface of the second N-type ohmic contact layer 323 in the second light-emitting unit 32 is covered with a portion of the cathode layer 70; a third insulating layer 63, the third insulating layer 63 is filled and formed outside the second light-emitting unit 32; a third groove structure 43, the third groove structure 43 runs through the third insulating layer 63, and one end of the third groove structure 43 is connected to the cathode layer 70. Among them, the bonding layer 322 can be an opaque metal material, such as a single layer or multiple layers of metals such as Au, Sn, Al, Cu, W, etc., and the bonding layer 322 can also be a transparent metal oxide material, such as a transparent conductive film such as ITO, ZnO, etc. The third insulating layer 63 can be a single layer or a stack of dielectric layers such as silicon oxide, silicon nitride, SIC, SICN, Ti3O5, Ni2O5, etc. The thickness of the third insulating layer 63 and the depth of the third trench structure 43 are greater than or equal to the thickness of the second light-emitting unit 32, and the depth of the third trench structure 43 can be set to any value greater than or equal to the thickness of the second light-emitting unit 32. For example, based on Fig.10 As shown in the structure, when the depth of the third trench structure 43 is equal to the height of the second light emitting unit 32, as shown in Fig.14 As shown in FIG. 1 , the luminous angle is reduced from the initial ±55° to ±45°; based on Fig.11 As shown in the structure, when the depth of the third trench structure 43 is more than twice the height of the second light emitting unit 32, as shown in Fig.15 As shown, the luminous angle is reduced from the initial ±55° to ±17°.

[0155] Furthermore, the cathode layer 70 includes: a middle cathode layer 71 and side cathode layers 72 on both sides. The middle cathode layer 71 is covered on the surface of the second N-type ohmic contact layer 323 .

[0156] In one possible design, Fig.10 , Fig.11As shown, the side wall of the second light-emitting unit 32 and the surface of the driving backplane 10 are covered with a passivation layer 80, and the side cathode layer 72 is covered on the surface of the passivation layer 80. Among them, the passivation layer 80 can be a single layer or a stack of dielectric layers such as Al2O3, SiO2, Si3N4, etc. The second light-emitting unit 32 and the driving backplane 10 are insulated and protected by the passivation layer 80, and the common cathode connection is achieved through the side cathode layer 72 covered on the surface of the passivation layer 80 and the middle cathode layer 71 covered on the surface of the second N-type ohmic contact layer 323.

[0157] In another possible design, Fig.12 As shown, the side cathode layer 72 is covered on the side surface of the third insulating layer 63 away from the driving backplane 10. The side cathode layer 72 covered on the surface of the third insulating layer 63 and the middle cathode layer 71 covered on the surface of the second N-type ohmic contact layer 323 realize the common cathode connection.

[0158] Further, such as Fig.13 As shown in FIG. 1 , when the side cathode layer 72 is covered on the side surface of the third insulating layer 63 away from the driving backplane 10, the side wall of the second light-emitting unit 32 and the surface of the driving backplane 10 are also covered with a passivation layer 80. The passivation layer 80 can be a single layer or a stack of dielectric layers such as Al2O3, SiO2, Si3N4, etc. That is, the third insulating layer 63 can be as follows Fig.12 As shown, the surface of the driving backplane 10 is directly connected, and the passivation layer 80 is not provided between the third insulating layer 63 and the driving backplane 10, and the dielectric layer on the driving backplane 10 is used to withstand the etching; Fig.13 As shown, a passivation layer 80 is disposed between the third insulating layer 63 and the driving backplane 10 . The passivation layer 80 is used as an etching stop layer to insulate and protect the second light emitting unit 32 and the driving backplane 10 .

[0159] Furthermore, a microlens 50 may be disposed on the third display device layer 23. For example, Fig.16 The structure shown corresponds to Fig.11 A micro lens 50 is added to the corresponding structure. Fig.17 The structure shown corresponds to Fig.13 A microlens 50 is added to the corresponding structure.

[0160] (3) The micro-display luminous pixel adopts a design concept of combining front and back groove structures. In the preparation process corresponding to this structural design, the front groove structure design concept is first adopted to prepare a group of groove structures 40 in a display device layer in the display module 20, and then the display module 20 is combined with the driving backplane 10. Subsequently, the back groove structure design concept is further adopted. For the combined device, another display device layer is added to the display module 20 to prepare another group of groove structures 40.

[0161] Specifically, Fig.18 As shown, on the basis of the first display device layer 21, the display module 20 also includes: a second display device layer 22 arranged on the first display device layer 21; the second display device layer 22 includes: a second insulating layer 62, the second insulating layer 62 is filled and formed on the side of the first display device layer 21 away from the driving backplane 10; a second groove structure 42, the second groove structure 42 runs through the second insulating layer 62 and the first N-type ohmic contact layer 313, and one end of the second groove structure 42 is connected to the first groove structure 41. Among them, the second insulating layer 62 can be a single layer or a stack of dielectric layers such as silicon oxide, silicon nitride, SIC, SICN, Ti3O5, Ni2O5, etc. Among them, the thickness of the second insulating layer 62 and the depth of the second groove structure 42 are not related to the thickness of the first light-emitting unit 31, and the depth of the second groove structure 42 can be freely set.

[0162] Furthermore, the width of the second trench structure 42 is smaller than the width of the first trench structure 41. On the one hand, the photolithography alignment deviation can be retained to reduce the process difficulty. On the other hand, the first trench structure 41 can be connected to the first N-type ohmic contact layer 313 to achieve cathode connection. Typically, the second trench structure 42 on the back side has 50% of the size of the first trench structure 41 on the front side.

[0163] Further, such as Fig.19 As shown, a microlens 50 may be disposed on the second display device layer 22 .

[0164] In summary, the micro-display luminous pixel provided in the embodiment of the present application achieves better optical crosstalk isolation by etching a groove structure in the display module of the micro-display luminous pixel and filling the groove structure with metal material, and through the through-type groove structure, and can customize the light-emitting angle through the depth of the groove structure. The design process of the groove structure is relatively mature, and mass production and yield are guaranteed.

[0165] Furthermore, the light-emitting unit and the groove structure in the display module belong to an inorganic material system, which has good temperature resistance and mechanical strength, and the reliability is guaranteed.

[0166] Furthermore, the invention provides a back side groove structure design idea, a back side groove structure design idea, and a front side and back side groove structure combined design idea, and different schemes can be freely selected according to needs.

[0167] Next, the method for preparing the micro-display luminescent pixel described in the above embodiment is described. The method is used to prepare the micro-display luminescent pixel described in the above embodiment. Fig. 20 As shown, the method may include the following steps:

[0168] S1: Prepare a driver backplane.

[0169] For example, the cross-sectional structure of a single pixel of the driving backplane is as follows: Fig.21 As shown, the driving back plate 10 includes a penetrating anode contact 11 , and an insulating medium is arranged around the anode contact 11 .

[0170] S2: Prepare a display module combined with a driving backplane, the display module includes a light-emitting unit and a groove structure, the light-emitting unit is connected to the anode contact in the driving backplane, the groove structure surrounds the light-emitting unit and penetrates the vertical area where the display module is located, the groove structure is filled with metal material, and the light-emitting unit is an inorganic compound semiconductor.

[0171] For example, the cross-sectional structure of an inorganic compound semiconductor is as follows: Fig. 22 As shown, the inorganic compound semiconductor at least includes the following layers stacked in sequence from bottom to top: a first substrate 316 , a first N-type ohmic contact layer 313 , a first active quantum well layer 317 and a first P-type ohmic contact layer 311 .

[0172] In a possible implementation, after S2, the following step is further included: preparing a microlens on the light-emitting unit and the groove structure. The microlens can be prepared by etching, and the microlens material can be a compound semiconductor, or a subsequently deposited dielectric material such as silicon oxide, silicon nitride, etc.

[0173] According to the front groove structure design idea in the above embodiment, S2 may specifically include the following steps:

[0174] S211: performing step etching on the inorganic compound semiconductor to prepare a first light-emitting unit.

[0175] Specifically, Fig.23 As shown, a patterned etching scheme such as plasma dry etching is used to perform step etching on the inorganic compound semiconductor until the first N-type ohmic contact layer 313 is etched to prepare the first light-emitting unit 31 , and the etching depth is in the range of 0.3 um to 3 um.

[0176] S212: Use an insulating material to perform step-filling on the first light-emitting unit to form a first insulating layer.

[0177] Specifically, a single layer or a stack of dielectric layers such as silicon oxide, silicon nitride, SIC, SICN, Ti3O5, Ni2O5, etc. is used to perform step filling on the first light-emitting unit to form a first insulating layer.

[0178] S213: Etching the first insulating layer to form a through hole connected to the first P-type ohmic contact layer in the first light-emitting unit and a first trench structure surrounding the first light-emitting unit.

[0179] Specifically, Fig.24 As shown, the first insulating layer 61 is etched using a patterned etching scheme such as plasma dry etching to achieve a through hole of the first P-type ohmic contact layer 311 and trench isolation around the first light-emitting unit 31. The thickness of the first insulating layer 61 and the depth of the first trench structure 41 are greater than or equal to the depth of pixel etching, generally 0.4um to 5um, the width of the first trench structure 41 is 90nm to 5um, and the angle of the first trench structure 41 is 90°±30°, with 90°±10° being optimal.

[0180] S214: filling the through hole and the first trench structure with metal material, and combining the first light-emitting unit, the first insulating layer, and the first trench structure into a first display device layer.

[0181] Specifically, Fig.25 As shown, metal materials are filled into the through hole 312 and the first trench structure 41 through a metal backfilling process, for example: metals Al, NiV, and Cu are deposited in the through hole 312 and the first trench structure 41 in sequence; or, metal Al is deposited in the through hole 312 and the first trench structure 41; or, metal W is deposited in the through hole 312 and the first trench structure 41. This structure can simultaneously complete the optical pixel string isolation and the electrical connection of the cathode, and the seed layer corresponding to the filled metal material can also be a single layer or multiple layers of metals such as Ti, Ni, Cr, Au, Ge, Al, Pt, Ta, W, or their nitrides. Furthermore, after the filling is completed, chemical mechanical planarization (CMP) can be used to remove excess metal from the surface of the filled metal material and planarize it.

[0182] S215: The first display device layer is combined with the driving backplane through a hybrid bonding process, and when combined, the first light-emitting unit is connected to the anode contact in the driving backplane through the through hole filled with metal material.

[0183] like Fig.26 As shown, when combined, the metal through hole area in the first display device layer 21 is connected to the anode contact 11 of the driving backplane, and the cathode of the first display device layer 21 is connected to the peripheral common cathode of the driving backplane 10 through the first groove structure 41.

[0184] In a possible implementation, after S215, the following steps are further included: removing the compound substrate in the first light-emitting unit; and roughening the surface of the first light-emitting unit after the substrate is removed. The compound substrate is removed from the first light-emitting unit 31 after the combination, and the cathode is thinned while the N contact is turned on by removing the substrate and thinning the compound, thereby reducing the optical crosstalk between pixels, and obtaining Figure 7 Further, as Fig. 27As shown, the surface of the first light emitting unit 31 after the substrate is removed is roughened to enhance the light extraction efficiency.

[0185] It can be understood that if the above-mentioned front groove structure design idea is adopted, the advantage is that an N-type ohmic contact can be directly formed with the first light-emitting unit; the disadvantage is that the pattern of the first light-emitting unit has been defined during bonding, and a certain precision is required to combine with the driving backplane. At the same time, it is limited by the thickness of the first light-emitting unit in the first display device layer, and the thickness of the first groove structure cannot be customized very flexibly.

[0186] It is understandable that in the above steps S211 to S215, the subsequent preparation is performed based on step etching to the first N-type ohmic contact layer. In another design, the step etching can be as follows: Fig.28 As shown, the inorganic compound semiconductor except the first substrate 316 is completely etched through, and accordingly, a process step is added to extend the first N-type ohmic contact layer 311 to connect with the first groove structure 41, so as to connect the cathode of the first display device layer 21 to the peripheral common cathode of the driving backplane 10 through the first groove structure 41.

[0187] With respect to the front and back groove structures in the above embodiment and the design ideas, after S215, the following steps may be further included:

[0188] S216: Filling the first display device layer with an insulating material to form a second insulating layer.

[0189] Specifically, a single layer or a stack of dielectric layers such as silicon oxide, silicon nitride, SIC, SICN, Ti3O5, Ni2O5, etc. is used to fill the first display device layer to form the second insulating layer.

[0190] S217: Etching the second insulating layer to form a second trench structure having one end connected to the first trench structure.

[0191] Specifically, the second insulating layer is etched using a patterned etching scheme such as plasma dry etching to achieve trench isolation around the first light-emitting unit in the second insulating layer, and the trench isolation is the second trench structure. The width of the second trench structure is 90nm to 5um, and the angle of the second trench structure is 90°±30°, with 90°±10° being optimal.

[0192] S218: filling the second trench structure with metal material, and combining the second insulating layer and the second trench structure into a second display device layer.

[0193] Specifically, the second trench structure is filled with metal materials through a metal backfilling process, for example: metals Al, NiV, and Cu are deposited in sequence in the second trench structure; or, metal Al is deposited in the second trench structure; or, metal W is deposited in the second trench structure. This structure can simultaneously complete the optical pixel string isolation and the electrical connection of the cathode, and the seed layer corresponding to the filled metal material can also be a single layer or multiple layers of metals such as Ti, Ni, Cr, Au, Ge, Al, Pt, Ta, W, or their nitrides. Furthermore, after the filling is completed, CMP can be used to remove excess metal from the surface of the filled metal material and flatten it.

[0194] It can be understood that if the above-mentioned front and back groove structures are combined with the design concept, the advantage is that an N-type ohmic contact can be directly formed with the first light-emitting unit, and the depth of the second groove structure on the back side can be customized very flexibly; the disadvantage is that the first light-emitting unit has a defined pattern during bonding, and a certain precision is required to be combined with the driving backplane, which increases the process cost.

[0195] According to the design idea of ​​the back side groove structure in the above embodiment, S2 may specifically include the following steps:

[0196] S221: combining an inorganic compound semiconductor with a bonding layer and a driving backplane with a bonding layer through a hybrid bonding process, wherein the inorganic compound semiconductor is electrically connected to the anode contact in the driving backplane through the bonding layer.

[0197] Specifically, Fig.29 , Fig.30 As shown, a bonding layer 322 is prepared on the inorganic compound semiconductor, and a bonding layer 322 is also prepared on the wafer of the driving backplane 10. The structure after the combination is as shown in FIG. Fig.31 As shown, the bonding layer 322 is conductive and can be an opaque metal material, such as a single layer or multiple layers of metals such as Au, Sn, Al, Cu, W, etc. The bonding layer 322 can also be a transparent metal oxide material, such as transparent conductive films such as ITO, ZnO, etc.

[0198] Furthermore, a metal such as Cr, Ni, Ti, TiN, etc. is provided between the inorganic compound semiconductor / driving backplane 10 and the bonding layer 322 as an adhesion layer to increase the adhesion between the two. Fig.31 As shown, after the compound wafer is integrated with the wafer of the driving backplane 10 through a bonding process, the second substrate 324 of the inorganic compound semiconductor can be removed for preparing subsequent devices.

[0199] S222: performing step etching on the inorganic compound semiconductor and the bonding layer to prepare a second light-emitting unit.

[0200] Specifically, Fig.32 As shown, a patterning etching scheme such as plasma dry etching is used for step etching to complete the preparation of the second light-emitting unit 32 and the patterning of the bonding layer 322. The etching depth corresponding to the second light-emitting unit 32 is in the range of 0.3um to 3um.

[0201] S223a: A passivation layer is provided on the surface of the second light-emitting unit and the surface of the driving backplane; a portion of the passivation layer on the top surface of the second light-emitting unit is removed by a graphical process to expose the second N-type ohmic contact layer in the second light-emitting unit; a cathode layer is provided on the surface of the second N-type ohmic contact layer and the surface of the passivation layer; the second light-emitting unit is step-filled with an insulating material to form a third insulating layer; the third insulating layer is etched to form a third groove structure surrounding the second light-emitting unit; and the third groove structure is filled with metal material.

[0202] In step S223a, the common cathode is connected before the trench process. The micro display light-emitting pixel manufactured by this step is as follows: Fig.10 , 11 Specifically, after passivation and patterning, the second N-type ohmic contact layer 323 in the second light-emitting unit 32 is exposed for contact preparation, and then the cathode layer 70 is prepared. The structure of the cathode layer 70 after preparation is as shown in FIG. Fig.33 As shown, the cathode layer 30 is connected to a transparent conductive film with a common cathode. The transparent conductive film can be a single layer or multiple layers of a transparent conductive film such as ITO, ZnO, etc. In some embodiments, the resistance and transmittance of the transparent conductive film can be optimized by metal doping such as Au, Ag, Al, etc. Then, by further growing a dielectric layer, a third insulating layer 63 is prepared using a plasma deposition process such as silicon glass, and after planarization, the third trench structure 43 is etched. The thickness of the third insulating layer 63 and the depth of the third trench structure 43 are greater than or equal to the depth of pixel etching, generally 0.4um to 5um, the width of the third trench structure 43 is 90nm to 5um, and the angle of the third trench structure 43 is 90°±30°, with 90°±10° being optimal. After etching, metal filling is performed, for example: metals Al, NiV, and Cu are deposited in sequence in the third trench structure 43; or, metal Al is deposited in the third trench structure 43; or, metal W is deposited in the third trench structure 43. This structure can simultaneously complete the optical pixel string isolation and the electrical connection of the cathode. The seed layer corresponding to the filled metal material can also be a single layer or multiple layers of metals such as Ti, Ni, Cr, Au, Ge, Al, Pt, Ta, W or their nitrides. Furthermore, after the filling is completed, CMP can be used to remove excess metal from the surface of the filled metal material and flatten it. Furthermore, when preparing the third trench structure 43 process, the IO and the peripheral common cathode can be simultaneously metal filled to achieve perfect functions.

[0203] S223b: Use insulating material to step-fill the second light-emitting unit to form a third insulating layer; etch the third insulating layer to form a third groove structure surrounding the second light-emitting unit; fill the third groove structure with metal material; use a graphical process to remove part of the third insulating layer on the top surface of the second light-emitting unit to expose the second N-type ohmic contact layer in the second light-emitting unit; cover the surface of the second N-type ohmic contact layer and the surface of the third insulating layer on the side away from the driving backplane with a cathode layer.

[0204] In step S223b, the trench process is performed before the common cathode connection. The micro display light-emitting pixel manufactured by this step is as follows: Fig.12 Specifically, after the second light-emitting unit 32 is prepared, the third insulating layer 63 is directly introduced, and the third insulating layer 63 is prepared by further growing a dielectric layer and using a plasma deposition process such as silicon glass. The structure after the third insulating layer 63 is introduced is as shown in FIG. Fig.34 Then, after the third insulating layer 63 is planarized, the third trench structure 43 is etched, and the dielectric layer on the driving backplane 10 is used to withstand the etching, and metal filling is performed after etching, for example: metal Al, NiV, and Cu are deposited in the third trench structure 43 in sequence; or metal Al is deposited in the third trench structure 43; or metal W is deposited in the third trench structure 43. The structure after metal filling is completed is as shown in FIG. Fig.35 As shown. This structure can simultaneously complete the optical pixel string isolation and the electrical connection of the cathode, and the seed layer corresponding to the filled metal material can also be a single layer or multiple layers of metals such as Ti, Ni, Cr, Au, Ge, Al, Pt, Ta, W or their nitrides. Furthermore, after the filling is completed, CMP can be used to remove excess metal from the surface of the filled metal material and flatten it. Then a graphic opening is performed to expose the second N-type ohmic contact layer 323 in the second light-emitting unit 32 for contact preparation, and then connect the cathode layer 70.

[0205] In a possible implementation, in S223b, before using an insulating material to perform step filling on the second light-emitting unit to form a third insulating layer, the following step is also included: a passivation layer is provided on the surface of the second light-emitting unit and the surface of the driving backplane. That is, the passivation layer 80 is used as a groove to prepare a corresponding etching stop layer, and the structure after step filling is as follows: Fig.36 As shown, the structure after trench etching and metal filling is as follows Fig.37 As shown, the micro display luminous pixel manufactured through this step is as follows Fig.13 shown.

[0206] It can be understood that if the above-mentioned back groove structure design concept is adopted, the advantage is that the pattern of the second light-emitting unit has not been defined during bonding, the precision requirement is very low when combined with the driving backplane, and the depth of the third groove structure can be flexibly customized by adjusting the thickness of the third insulating layer; the disadvantage is that the N-type ohmic contact corresponding to the second light-emitting unit needs to be prepared separately.

[0207] In summary, the method for preparing a micro-display luminous pixel provided in the embodiment of the present application achieves better optical crosstalk isolation by etching a groove structure in the display module of the micro-display luminous pixel and filling the groove structure with metal material, and a through-type groove structure. The luminous angle can be customized by the depth of the groove structure, and the design process of the groove structure is relatively mature, and mass production and yield are guaranteed.

[0208] Furthermore, the preparation method adopts semiconductor technology, which is compatible with nanoscale work and is more suitable for the preparation of micro-pixel sizes.

[0209] All of the above optional technical solutions can be combined in any way to form optional embodiments of the present invention, that is, any multiple embodiments can be combined to meet the needs of different application scenarios. They are all within the protection scope of this application and will not be described one by one here.

[0210] It should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A crosstalk-proof micro-display luminous pixel, characterized in that: The micro display luminous pixel size is in the range of 0.5um to 50um, and the micro display luminous pixel includes: Driver backplane; A display module is provided on the driving backplane, the display module includes a light-emitting unit and a groove structure, the light-emitting unit is connected to the anode contact in the driving backplane, the groove structure surrounds the light-emitting unit and penetrates the vertical area where the display module is located, the groove structure is filled with metal material, and the light-emitting unit is an inorganic compound semiconductor.

2. The micro display luminescent pixel according to claim 1, characterized in that: The display module at least includes: a first display device layer; the first display device layer includes: A first light-emitting unit, wherein a first P-type ohmic contact layer in the first light-emitting unit is connected with a through hole, and the first light-emitting unit is electrically connected to an anode contact in the driving backplane through the through hole filled with a metal material; A first insulating layer, wherein the first insulating layer is filled and formed outside the first light emitting unit; A first groove structure, wherein the first groove structure penetrates the first insulating layer, one end of the first groove structure is connected to the first N-type ohmic contact layer in the first light-emitting unit, and the other end is connected to the upper surface of the driving backplane.

3. The micro display luminescent pixel according to claim 2, characterized in that: The display module further includes: a second display device layer disposed on the first display device layer; the second display device layer includes: A second insulating layer, the second insulating layer is filled and formed on a side of the first display device layer away from the driving backplane; A second trench structure, wherein the second trench structure penetrates the second insulating layer and the first N-type ohmic contact layer, and one end of the second trench structure is connected to the first trench structure.

4. The micro display luminescent pixel according to claim 3, characterized in that: The width of the second trench structure is smaller than the width of the first trench structure.

5. The micro display luminescent pixel according to claim 1, characterized in that: The display module at least includes: a third display device layer; the third display device layer includes: A second light-emitting unit, wherein a bonding layer is provided between the second P-type ohmic contact layer in the second light-emitting unit and the driving backplane, the second light-emitting unit is electrically connected to the anode contact in the driving backplane through the bonding layer, and a surface of the second N-type ohmic contact layer in the second light-emitting unit is covered with a portion of a cathode layer; a third insulating layer, the third insulating layer being filled and formed outside the second light emitting unit; A third trench structure is provided, wherein the third trench structure penetrates the third insulating layer, and one end of the third trench structure is connected to the cathode layer.

6. The micro display luminescent pixel according to claim 5, characterized in that: The cathode layer includes: a middle cathode layer and side cathode layers on both sides, wherein the middle cathode layer is covered on the surface of the second N-type ohmic contact layer; The side wall of the second light emitting unit and the surface of the driving backplane are covered with a passivation layer, and the side cathode layer is covered on the surface of the passivation layer; or, The side cathode layer is covered on a surface of the third insulating layer which is away from the driving back plate.

7. The micro display luminescent pixel according to claim 6, characterized in that: In the case where the side cathode layer is covered on a surface of the third insulating layer away from the driving backplane, the side wall of the second light emitting unit and the surface of the driving backplane are further covered with a passivation layer.

8. The micro display luminescent pixel according to claim 1, characterized in that: The groove structures corresponding to adjacent light-emitting units are interconnected; or, The groove structures corresponding to adjacent light-emitting units are isolated from each other by an insulating medium.

9. The micro display luminescent pixel according to claim 1, characterized in that: The groove pattern corresponding to the groove structure in a top view includes: One of circle, rectangle, hexagon and octagon.

10. The micro display luminescent pixel according to claim 1, characterized in that: The display module further includes: a micro lens; The microlens is arranged on the light emitting unit and the groove structure.

11. The micro display luminescent pixel according to claim 1, characterized in that: The metal material filled in the groove structure includes: Aluminum, nickel, vanadium, and copper are deposited vertically in sequence; or, deposited aluminum; or, deposited tungsten.

12. The micro display luminescent pixel according to claim 1, characterized in that: The overall depth of the groove structure is not less than the overall depth of the light emitting unit.

13. The micro display luminescent pixel according to claim 1, characterized in that: The width of the groove structure is in the range of 90nm to 5um.

14. The micro display luminescent pixel according to claim 1, characterized in that: The depth of the groove structure is in the range of 0.4um to 5um.

15. The micro display luminescent pixel according to claim 1, characterized in that: The angle of the groove structure gradually increases in a direction away from the driving back plate.

16. A method for preparing a micro-display luminous pixel, characterized in that: The method is used to prepare the micro display luminous pixel according to any one of claims 1 to 15, and the method comprises: preparing a drive backplane; A display module combined with the driving backplane is prepared, wherein the display module includes a light-emitting unit and a groove structure, wherein the light-emitting unit is electrically connected to an anode contact in the driving backplane, the groove structure surrounds the light-emitting unit and penetrates a vertical region where the display module is located, the groove structure is filled with a metal material, and the light-emitting unit is an inorganic compound semiconductor.

17. The method according to claim 16, characterized in that The preparation of the display module combined with the driving backplane includes: Performing step etching on the inorganic compound semiconductor to prepare a first light-emitting unit; Using an insulating material to perform step filling on the first light-emitting unit to form a first insulating layer; Etching the first insulating layer to form a through hole connected to the first P-type ohmic contact layer in the first light-emitting unit and a first groove structure surrounding the first light-emitting unit; Filling the through hole and the first groove structure with metal material, and combining the first light-emitting unit, the first insulating layer, and the first groove structure into a first display device layer; The first display device layer is combined with the driving backplane through a hybrid bonding process, and during the combination, the first light-emitting unit is connected to the anode contact in the driving backplane through the through hole filled with metal material.

18. The method according to claim 17, characterized in that After combining the first display device layer with the driving backplane, the method further includes: removing the compound substrate in the first light-emitting unit; The surface of the first light-emitting unit is roughened after the substrate is removed.

19. The method according to claim 17, characterized in that After forming the first display device layer, the method further includes: Filling the first display device layer with an insulating material to form a second insulating layer; Etching the second insulating layer to form a second trench structure having one end connected to the first trench structure; The second trench structure is filled with metal material, and the second insulating layer and the second trench structure are combined into a second display device layer.

20. The method according to claim 16, characterized in that The preparation of the display module combined with the driving backplane includes: The inorganic compound semiconductor prepared with a bonding layer and the driving backplane prepared with a bonding layer are combined by a hybrid bonding process, wherein the inorganic compound semiconductor is connected to the anode contact in the driving backplane through the bonding layer during the combination; Performing step etching on the inorganic compound semiconductor and the bonding layer to prepare a second light-emitting unit; The second light-emitting unit is step-filled with an insulating material to form a third insulating layer; the third insulating layer is etched to form a third groove structure surrounding the second light-emitting unit; the third groove structure is filled with a metal material; a portion of the third insulating layer on the top surface of the second light-emitting unit is removed by a patterning process to expose the second N-type ohmic contact layer in the second light-emitting unit; a cathode layer is covered on the surface of the second N-type ohmic contact layer and on the side of the third insulating layer away from the driving backplane; or, A passivation layer is covered on the surface of the second light-emitting unit and the surface of the driving backplane; a portion of the passivation layer on the top surface of the second light-emitting unit is removed by a graphic process to expose the second N-type ohmic contact layer in the second light-emitting unit; a cathode layer is covered on the surface of the second N-type ohmic contact layer and the surface of the passivation layer; the second light-emitting unit is step-filled with an insulating material to form a third insulating layer; the third insulating layer is etched to form a third groove structure surrounding the second light-emitting unit; and the third groove structure is filled with a metal material.

21. The method according to claim 20, characterized in that In a method corresponding to covering a cathode layer on a surface of the second N-type ohmic contact layer and a surface of the third insulating layer on a side away from the driving backplane, before step-filling the second light-emitting unit with an insulating material to form the third insulating layer, the method further includes: A passivation layer is provided on the surface of the second light emitting unit and the surface of the driving backplane.

22. The method according to claim 16, characterized in that After preparing the display module combined with the driving backplane, the method further includes: A microlens is prepared on the light emitting unit and the groove structure.

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