CN110828646B

CN110828646B - Manufacturing method of micro LED display

Info

Publication number: CN110828646B
Application number: CN201810899850.8A
Authority: CN
Inventors: 林钢; 吕岳敏; 林敏�
Original assignee: Shantou Goworld Display Technology Co Ltd
Current assignee: Shantou Goworld Display Technology Co Ltd
Priority date: 2018-08-09
Filing date: 2018-08-09
Publication date: 2020-12-08
Anticipated expiration: 2038-08-09
Also published as: CN110828646A

Abstract

A manufacturing method of a micro LED display comprises the following steps of providing a plurality of micro LEDs with first hydrophobic layers on one sides and a driving substrate with second hydrophobic layers, wherein the driving substrate is provided with a bonding pad, and the second hydrophobic layers are left empty on the bonding pad: the method comprises the following steps that firstly, micro LEDs are floated in polar liquid to form floating liquid and are arranged on a first surface of a driving substrate; gradually evaporating the polar liquid to enable the micro LED to be positioned on the bonding pad; and step three, bonding the micro LED with the bonding pad. The manufacturing method of the micro LED display can transfer and bond a huge amount of micro LEDs to a driving substrate more quickly and efficiently to form the micro LED display.

Description

Manufacturing method of micro LED display

Technical Field

The invention relates to a manufacturing method of a micro LED display, belonging to the technical field of manufacturing of displays.

Background

Micro LED displays, such as micro-LEDs or mini-LEDs, are typically constructed by transferring and bonding a huge number of micro LEDs (light emitting diodes having a diameter of less than 500 μm) onto a substrate of driving circuitry. The micro LED display has advantages of good display performance (active light emission, high brightness, high contrast, high color gamut, wide viewing angle, fast response), energy saving, long service life, etc., and is considered to be a more advanced display type than the liquid crystal display and the organic light emitting display. In the prior art, a huge number of micro LEDs are transferred and bonded onto a driving substrate to form a micro LED display, which is generally realized by adopting a method of transferring the micro LEDs one by one (or a plurality of batches of) by a transfer head, and the transfer speed is slow, the efficiency is low, and the mass production of the micro LED display is difficult to realize.

Therefore, how to transfer and bond the micro LEDs to the driving substrate more efficiently to form the LED array device in the manufacture of the micro LED display is an important issue facing the micro LED display manufacturing technology at present.

Disclosure of Invention

The invention aims to provide a manufacturing method of a micro LED display, which can transfer and bond a huge amount of micro LEDs onto a driving substrate to form the micro LED display more quickly and efficiently, and adopts the following technical scheme:

a manufacturing method of a micro LED display is characterized in that:

providing a plurality of micro LEDs with a first hydrophobic layer, wherein the micro LEDs comprise a semiconductor light emitting layer, a first bonding layer and a first electrode are respectively arranged on the inner side and the outer side of the semiconductor light emitting layer, and the first hydrophobic layer is arranged on the outer side of the first electrode;

providing a driving substrate, wherein a driving circuit layer is arranged on a first surface of the driving substrate, the driving circuit layer comprises a plurality of bonding pads and a driving circuit connected to the bonding pads, a second bonding layer is arranged on the surface of each bonding pad, a second hydrophobic layer is further arranged on the surface of the driving circuit layer, and a space is reserved at each bonding pad of each second hydrophobic layer;

and, the following processing steps are adopted:

floating the micro LED with the first hydrophobic layer in polar liquid to form floating liquid, spraying the floating liquid to the first surface of the driving substrate, and utilizing the removing effect of the first hydrophobic layer on the polar liquid to enable the micro LED to float outwards on the surface of the floating liquid through the first hydrophobic layer, so that the first bonding layer of the micro LED faces to the driving circuit; or polar liquid is sprayed on the first surface of the driving substrate, then the micro LEDs are sprayed on the driving liquid, the micro LEDs float outwards on the surface of the polar liquid through the first hydrophobic layer by utilizing the removing effect of the first hydrophobic layer on the polar liquid, and therefore the first bonding layer of the micro LEDs faces the driving circuit;

gradually evaporating the polar liquid, forming a plurality of liquid beads corresponding to the bonding pad by the polar liquid under the action of a second hydrophobic layer, gradually positioning the micro LED on the bonding pad under the action of the surface of the liquid beads which are continuously shrunk, and tightly attaching a first bonding layer of the micro LED to a second bonding layer on the bonding pad when the polar liquid is completely evaporated;

bonding the first bonding layer and the second bonding layer;

and fourthly, arranging an external driving circuit on the first electrode, thereby forming the micro LED display.

Specifically, the micro LED may be a GaP, GaAs, GaN, or the like series of micro LEDs. Preferably, the micro LED is a micro LED with a vertical structure, that is, the P pole and the N pole of the micro LED are respectively located at two opposite sides of the device, thereby respectively constituting the first bonding layer and the first electrode (or the first electrode and the first bonding layer): the first bonding layer may be a doped semiconductor layer (e.g., a P-type layer) on one side of the micro LED, or may be a conductor film layer covering one side of the micro LED, such as a gallium metal (Ga) film obtained by decomposing the semiconductor layer; the first electrode can be a doped semiconductor layer (such as an N-type layer) on the other side of the micro LED, or a transparent conductive film layer (such as an ITO film on the N-type layer) covering the other side of the micro LED. A semiconductor light emitting layer (including a P-type layer, an N-type layer, and a quantum well layer) of a vertical structure micro LED is generally grown on an epitaxial substrate (e.g., sapphire) by an epitaxial method (e.g., MOCVD epitaxy), and is finally peeled off from the epitaxial substrate by a laser lift-off method (i.e., laser is irradiated to the bottom of the semiconductor light emitting layer through the epitaxial substrate to decompose the semiconductor light emitting layer). In a preferred embodiment of the present invention, the process for manufacturing the micro LED with the first hydrophobic layer includes:

(1) forming a semiconductor light emitting layer of a micro LED on an epitaxial substrate, the semiconductor light emitting layer including an inner first bonding layer and an outer first electrode;

(2) arranging a first hydrophobic layer on the first electrode, wherein the first hydrophobic layer is a discrete coating layer positioned on the surface of the semiconductor light-emitting layer;

(3) and separating the semiconductor light emitting layer from the epitaxial substrate by laser lift-off, wherein the semiconductor light emitting layer contacted with the first hydrophobic layer is supported and kept intact by the first hydrophobic layer to form a plurality of mutually independent micro LEDs (the semiconductor light emitting layer not contacted with the first hydrophobic layer is broken and removed).

The first water-repellent layer is a discrete coating layer, that is, the first water-repellent layer is composed of a plurality of dots, particles or blocks separated from each other, so that in the laser lift-off process, according to the contact supporting principle of the first water-repellent layer on the semiconductor light-emitting layer, a plurality of micro LEDs independently provided with the first water-repellent layer and defined by the dots, particles or blocks can be finally formed, for example, the size (diameter) of each dot, particle or block can be 10-500 μm, so that a micro LED with the size of 10-500 μm can be obtained. The discrete first hydrophobic layer can be formed by yellow light process, printing and the like.

In the second step, the polar liquid may be water, alcohol or other liquid having polarity, so that the first and second hydrophobic layers have a large contact angle when in contact therewith to exhibit a significant repellent effect, and preferably, the polar liquid is water. In the second step, the floating liquid may be agitated to expose the first hydrophobic layer of the micro-LED to the liquid surface, thereby floating the micro-LED on the liquid surface — when the first hydrophobic layer is exposed to the liquid surface, the hydrophobic property thereof will remove the polar liquid on the surface of the hydrophobic layer, resulting in the micro-LED being "stuck" to the liquid surface. Preferably, the micro LED is doped into a polar liquid containing fine bubbles, and after standing, the bubbles in the polar liquid adhere to the first hydrophobic layer of the micro LED, so that the micro LED floats up, the first hydrophobic layer of the micro LED is exposed out of the liquid surface, and finally the micro LED is adhered to the liquid surface.

The first hydrophobic layer can be hydrophobic photosensitive resin, and can also be a non-polar polymer which is solid at normal temperature, such as aliphatic compounds or polyolefin compounds, and particularly non-polar polymers such as paraffin, polyethylene and polypropylene. Preferably, the density of the first hydrophobic layer is less than the polar liquid, whereby the micro LED with the first hydrophobic layer will naturally keep the first hydrophobic layer in the right direction towards the liquid surface in the polar liquid; in the case where the polar liquid is water, it is further preferred that the first hydrophobic layer is a discrete coating of polyethylene or polypropylene. Polyethylene or polypropylene not only has ideal hydrophobicity and is suitable for manufacturing the first hydrophobic layer of the micro LED, but also has the density smaller than that of water, besides, polyethylene or polypropylene material has good mechanical property, and the semiconductor light-emitting layer covered by the polyethylene or polypropylene material can be well protected from being broken in the laser stripping process. Polyethylene or polypropylene may be printed, etc. on the surface of the semiconductor light emitting layer in a molten or solvent-dissolved state, thereby forming discrete cladding layers. Further preferably, the overall average density of the micro-LEDs is less than the polar liquid, so that in step one or step two, the micro-LEDs may automatically float to the surface of the polar liquid. Specifically, when the polar liquid is water and the first hydrophobic layer is a polyethylene or polypropylene coating layer, the volume (thickness) of the first hydrophobic layer may be preferably 60 times or more that of the semiconductor light emitting layer, so that the overall average density of the micro LED with the first hydrophobic layer is less than that of water.

The driving substrate is preferably a glass substrate, a plastic substrate or a silicon substrate. The driving circuit layer may be a passive driving layer not including active devices (such as TFTs and MOSFETs), or may be an active driving layer including active devices. In the case of a passive driving layer, the driving circuit layer may be designed such that each pad is LED out by a lead wire, or may be designed as a cross matrix — the driving circuit layer may be designed only as row electrodes (pads are disposed on the row electrodes) constituting the cross matrix, and the column electrodes constituting the cross matrix are disposed after the micro LEDs are bonded. The driving circuit layer can be formed by a conductive film layer deposited (such as magnetron sputtering and evaporation) on the base layer, especially a metal film layer (such as Cu and Mo-Al-Mo) by a patterning method such as photoetching. In the case that the driving circuit layer is an active driving layer, the driving circuit layer may include a MOSFET device (corresponding to the case that the driving substrate is a silicon substrate) or a TFT device (corresponding to the case that the driving substrate is a glass substrate or a plastic substrate) for controlling each micro LED to emit light individually, the TFT device may be formed of silicon (such as α -Si), an oxide semiconductor, or an organic semiconductor, and in order to ensure that the micro LED has a sufficient driving current when operating, the TFT device is preferably formed of Low Temperature Polysilicon (LTPS) or Indium Gallium Zinc Oxide (IGZO) having a high electron mobility. The design of the active driving layer and the driving circuit can refer to the driving design of the existing AM-OLED display device, such as the pixel driving design using 2T1C (i.e. including two TFT devices and a capacitor, which is generally used in the driving circuit of AMOLED) or more complicated (e.g. further adding a compensation circuit), except that the pixel output terminal is changed to the pad. In the driving circuit layer, the distance between the pads is preferably 0.2-10 times of the size of the pad, the pads can be formed by the metal film layer (such as Cu, Mo-Al-Mo) through a patterning method such as photoetching, the width of the pad can be set to be more than 1.2 times of the size (diameter) of the micro LED, specifically, the width of the pad is preferably 1.2-1.6 times of the size (diameter) of the micro LED to form a design that one micro LED corresponds to one pad, or the width of the pad is more than 2.5 times of the size (diameter) of the micro LED, so that the design that one pad corresponds to a plurality of micro LEDs is formed, one pad corresponds to a plurality of micro LEDs is designed, although the pixel density is low, the one-to-one correspondence between the micro LEDs and the pads is not required, and the process difficulty is low.

Preferably, the second bonding layer on the surface of the pad is a metal layer with a low melting point, such as a metal layer or an alloy layer of indium or tin, which may be formed by combining a plating film (such as evaporation, magnetron bonding, electroplating) with a certain patterning manner (which may be patterned simultaneously with the pad), or may be formed by electroplating (which may be implemented by introducing current through the driving circuit layer) or hot dip plating based on the pattern of the pad. Therefore, in the third step, the first bonding layer and the second bonding layer can be soldered by reflow soldering.

In a preferred aspect of the present invention, the method of manufacturing the driving substrate includes:

arranging a driving circuit layer on the first surface of the glass substrate, wherein the driving circuit layer comprises a plurality of bonding pads and a driving circuit connected to the bonding pads, and the surface of each bonding pad is provided with a second bonding layer; and further arranging a second water-repellent layer on the surface of the driving circuit layer, and leaving a space for the second water-repellent layer at the bonding pad.

The second hydrophobic layer can be hydrophobic photosensitive resin, and can also be a non-polar polymer which is solid at normal temperature, such as aliphatic compounds or polyolefin compounds, and particularly non-polar polymers such as paraffin, polyethylene and polypropylene. Preferably, the second hydrophobic layer is also a coating or plating of polyethylene or polypropylene. The second hydrophobic layer can be arranged by printing, spraying or vacuum thermal evaporation (such as electron beam evaporation), and the like, and the second hydrophobic layer at the bonding pad is preferably ablated by adopting a laser ablation method, so that the second hydrophobic layer is vacant at the bonding pad; in addition, the bonding pad can be arranged to protrude from the surface of the driving substrate, and the second water-repellent layer at the bonding pad is polished away by means of mechanical polishing, so that the second water-repellent layer is left empty at the bonding pad. The thickness of the second hydrophobic layer can be set to be 1-100 mu m.

When the first and second hydrophobic layers are made of a similar fusible material, such as a hydrocarbon olefin polymer, it is preferable that the first and second hydrophobic layers are fused into a continuous film layer covering the surfaces of the driving circuit layer and the micro LED by using a high temperature of reflow soldering in the third step, so that the first and second hydrophobic layers can be directly torn off from the surfaces of the driving circuit layer and the micro LED in the fourth step. In addition, in the fourth step, the first hydrophobic layer and the second hydrophobic layer may be cleaned off by using an organic solvent, and further, the first hydrophobic layer and the second hydrophobic layer may be cleaned off from residues by using an oxygen ion ashing method.

In order to form the external driving circuit on the first electrode, after removing the first and second hydrophobic layers, a certain isolation layer may be formed on the surfaces of the driving circuit layer and the micro LEDs (e.g., by coating to form a photosensitive resin isolation layer), openings corresponding to the tops of the micro LEDs may be formed on the isolation layer (e.g., by yellow light, or by polishing the isolation layer on the tops of the micro LEDs when the micro LEDs protrude out), and finally, a driving electrode layer (e.g., an ITO layer) may be further deposited on the isolation layer, thereby forming the external driving circuit (e.g., by forming a certain circuit on the driving electrode layer by photolithography).

The invention provides a method for manufacturing a micro LED display, which comprises the steps of respectively arranging a first hydrophobic layer and a second hydrophobic layer on a micro LED and a driving substrate, enabling the micro LED to directionally float on the driving substrate (with a first bonding layer facing inwards) through polar liquid, gradually positioning the micro LED on a bonding pad in an inward correct posture by utilizing the hydrophobic effects of the first hydrophobic layer and the second hydrophobic layer in the gradual evaporation process of the polar liquid, and finally enabling the first bonding layer and the second bonding layer to be attached and bonded with each other. Compared with the existing manufacturing method of the micro LED display, the method can transfer and bond a huge amount of micro LEDs to a driving circuit substrate more quickly and efficiently to form the micro LED display.

The technical solution of the present invention is further explained by the accompanying drawings and examples.

Drawings

Fig. 1 is a schematic view of a micro LED according to a first embodiment of the present invention, which is fabricated by forming a semiconductor light emitting layer on a sapphire substrate;

fig. 2 is a schematic view of a first hydrophobic layer formed on a semiconductor light emitting layer during fabrication of the micro LED according to the first embodiment;

fig. 3 is a schematic perspective view of the first hydrophobic layer of fig. 2;

fig. 4 is a schematic view of laser lift-off in a semiconductor light emitting layer during fabrication of the micro LED according to the first embodiment;

FIG. 5 is a schematic diagram of the micro LEDs of the first embodiment when they are fabricated to form individual micro LEDs;

FIG. 6 is a schematic diagram of a driving circuit layer formed in the method for manufacturing a micro LED display according to the first embodiment;

fig. 7 is a schematic view illustrating a second hydrophobic layer formed in the method for manufacturing a micro LED display according to the first embodiment;

FIG. 8 is a schematic view of a floating liquid of micro LEDs in the method for manufacturing a micro LED display according to the first embodiment;

fig. 9 is a schematic view illustrating a method of manufacturing a micro LED display according to a first embodiment, in which a floating liquid of micro LEDs is sprayed on a driving substrate;

FIG. 10 is a schematic view showing the gradual evaporation of the floating liquid in the method for manufacturing a micro LED display according to the first embodiment;

FIG. 11 is a schematic view showing the micro LED display according to the first embodiment after the floating liquid is evaporated;

FIG. 12 is a schematic view of a micro LED display manufacturing method according to the first embodiment after reflow soldering;

FIG. 13 is a schematic view showing a polypropylene plastic film peeled off in the method for manufacturing a micro LED display according to the first embodiment;

FIG. 14 is a schematic diagram of a method for fabricating a micro LED display according to the first embodiment, in which an isolation layer and an outer electrode are formed;

FIG. 15 is a schematic view showing the gradual evaporation of the floating liquid in the method for manufacturing a micro LED display according to the second embodiment;

fig. 16 is a schematic view showing the method of manufacturing the micro LED display according to the second embodiment after the floating liquid is evaporated.

Detailed Description

Example one

As shown in fig. 1, N-type GaN, a quantum well and P-type GaN are sequentially epitaxially grown on a sapphire substrate 10 by using an MOCVD method to form a semiconductor light emitting layer 11, the overall thickness of the semiconductor light emitting layer 11 is 4 μm, and the P-type GaN layer outside the semiconductor light emitting layer can be used as a first electrode layer;

as shown in fig. 2 and 3, a polypropylene clad layer 12 as a first water-repellent layer is provided on a semiconductor light-emitting layer 11 by: polypropylene is kept in a molten state at about 200 ℃ and is printed on the surface of the semiconductor light-emitting layer 11 by steel plate printing (screen printing) in a thickness of 40 μm in a pattern of circular particles having a diameter of 50 μm, and after cooling, the first water-repellent layer 12 composed of discrete polypropylene particles 121 is formed on the semiconductor light-emitting layer 11.

As shown in fig. 4, KrF excimer ultraviolet laser light 13 is irradiated from the back surface of sapphire substrate 10, and penetrates sapphire substrate 10 to be absorbed by the bottom of semiconductor light-emitting layer 11, so that thermal decomposition occurs at the bottom of semiconductor light-emitting layer 11 (reaction formula: 2GaN =2Ga + N)₂) And thus the semiconductor light emitting layer 11 is separated from the sapphire substrate 10, the semiconductor light emitting layer 11 at the bottom of the first water-repellent layer particles 121 is kept intact under the support protection of the respective first water-repellent layer particles 121, while the semiconductor light emitting layer 11 without the support of the first water-repellent layer particles 121 is mostly broken (a small part of the semiconductor light emitting layer is adhered to the edge of the micro LED and is broken in the subsequent process), and as shown in fig. 5, the semiconductor light emitting layer 11 is washed from the sapphire substrate 10 by using DI water 20 to obtain the micro LED 30 with the first water-repellent layer 12(31) with the diameter of about 50 μm, wherein the Ga metal layer obtained by thermal decomposition at the bottom of the semiconductor light emitting layer 11 can be used as the first bonding layer 32 of the micro LED 30. The micro LEDs 30 float in the DI water 20 to form a floating liquid.

Manufacturing a driving substrate 40: as shown in fig. 6, a driving circuit layer 41 (no further circuit is shown, and reference may be made to the driving circuit design of the AM-OLED) is formed on the glass substrate by using an array manufacturing process (such as a nine-time top gate lithography process, or the related art of flexible AM-OLED) of LTPS, thereby forming a driving substrate 40. The driving circuit layer 41 includes a plurality of circular pads 42 with a diameter of 60 μm corresponding to the pixels of the display, and a 5 μm thick tin metal layer 421 (which may also be an indium metal layer) is plated on the surface of the pads 42 as a second bonding layer. As shown in fig. 7, a 20 μm thick polypropylene plating layer is further printed on the driving circuit layer 41, and the polypropylene plating layer at the bonding pad 42 is ablated by laser ablation to expose the entire bonding pad 42, thereby forming a second water-repellent layer 43.

The micro LEDs 30 are transferred and bonded to the driving substrate 40 to finally form a micro LED display, using the following steps:

the first step,

As shown in fig. 8, the floating liquid of the micro LED 30 is stirred and mixed with DI water (which may be formed by a micro-nano bubble generator) containing fine bubbles, and after standing, the micro bubbles 21 adhere to the first water-repellent layer 31 of the micro LED 30, thereby floating the micro LED 30 and exposing the first water-repellent layer 31 thereof to the liquid surface, and finally causing the micro LED 30 to be "adhered" to the liquid surface 22 in a posture that the first bonding layer 32 faces inward.

Step two,

As shown in fig. 9, the floating liquid of the micro LEDs 30 is sprayed on the driving substrate 40, the spraying amount of the floating liquid can be controlled according to the required number of the micro LEDs, so that the number of the micro LEDs 30 in the floating liquid corresponds to the number of the pads 42 on the driving substrate 40, after standing, because the density of the first water-repellent layer 31 is less than that of water, and under the action of the air bubbles and the drainage of the first water-repellent layer 31, the micro LEDs 30 always float on the surface 22 of the DI water 20 in the correct inward posture of the first bonding layer 32. As shown in fig. 10, the DI water 20 is gradually evaporated, and under the action of the second water-repellent layer 43, the DI water 20 first forms a plurality of water drops 23 corresponding to the pads 42; further, the micro LED 30 is driven by the surface of the gradually shrinking bead 23 to move and gradually position on the pad 42; as shown in fig. 11, when the evaporation of the DI water 20 is completed, the first bonding layer 32 of the micro LED 30 is attached to the second bonding layer 421 of the pad.

Step three,

Finally, the first bonding layer 32 and the second bonding layer 421 are soldered by reflow soldering. As shown in fig. 12, after passing through a high temperature (about 250 ℃) of a reflow furnace, the first and second water-

repellent layers

31 and 43, which are also polypropylene, are fused into a continuous plastic film 50 covering the surfaces of the driving circuit layer 41 and the micro LEDs 30.

Step four,

As shown in fig. 13, the polypropylene plastic film 50 is directly peeled off from the surface of the drive substrate 40. As shown in fig. 14, a photosensitive resin coating layer 44 as an isolation layer is coated on the surface of the driving substrate 40, an opening 441 of the isolation layer 44 is formed on the surface of the micro LED by a yellow light method, an ITO thin film 45 is deposited on the driving substrate 40 by a magnetron sputtering method, and it is patterned into an outer electrode 451 by a photolithography method, thereby completing the fabrication of the micro LED display.

Example two

As shown in fig. 15, in the second embodiment, the width of the bonding pad 42 is changed to 300 μm based on the first embodiment, and the number of micro LEDs 30 in the floating liquid is increased, so that, as shown in fig. 16, after the third step, a plurality of micro LEDs 30 are bonded to each bonding pad 42. In the fourth step, epoxy resin can be coated, leveled and cured on the surfaces of the driving circuit layer and the micro-LEDs to form an isolation layer, the epoxy resin layer on the surface of the micro-LEDs is polished to expose the first electrodes, and then a layer of ITO film is deposited on the surface of the driving circuit layer by a magnetron sputtering method and patterned into outer electrodes, thereby completing the manufacture of the micro-LED display.

EXAMPLE III

Example three on the basis of example one, the thickness of the polypropylene cladding layer as the first hydrophobic layer was increased to 300 μm, the printed pattern was circular particles with a diameter of 200 μm, and after cooling, a cladding layer of discrete particles was formed on the semiconductor light emitting layer, and the contact diameter between the bottom of the particles and the semiconductor light emitting layer was about 150 μm. Therefore, micro LEDs with the diameter of the semiconductor light emitting layer being 150 mu m can be finally formed, the thickness of the first hydrophobic layer of each micro LED exceeds 60 times of that of the semiconductor light emitting layer, and the overall average density of the micro LED is less than that of water. Thus, the micro-LEDs may automatically float to the liquid surface in step one or step two.

In addition, it should be noted that the names of the parts and the like of the embodiments described in the present specification may be different, and the equivalent or simple change of the structure, the characteristics and the principle described in the present patent idea is included in the protection scope of the present patent. Various modifications, additions and substitutions for the specific embodiments described may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.

Claims

1. A manufacturing method of a micro LED display is characterized in that:

the first electrode is a doped semiconductor layer on the outer side of the micro LED or a transparent conductive film layer covering the outer side of the micro LED;

and, the following processing steps are adopted:

the method comprises the following steps that firstly, the micro LED with the first hydrophobic layer floats in polar liquid to form floating liquid, the floating liquid is sprayed to the first surface of a driving substrate, and the micro LED floats outwards on the surface of the floating liquid through the first hydrophobic layer under the removing effect of the first hydrophobic layer on the polar liquid; or polar liquid is sprayed on the first surface of the driving substrate, then the micro LEDs are sprayed on the driving liquid, and the micro LEDs float on the surface of the polar liquid outwards through the first hydrophobic layer by utilizing the removing effect of the first hydrophobic layer on the polar liquid;

bonding the first bonding layer and the second bonding layer;

2. The manufacturing method according to claim 1, wherein: the micro LED is a micro LED with a vertical structure.

3. The method of manufacturing as claimed in claim 1, wherein the fabricating process of the micro LED with the first hydrophobic layer comprises:

forming a semiconductor light emitting layer of a micro LED on an epitaxial substrate, wherein the semiconductor light emitting layer comprises a first bonding layer on the inner side and a first electrode on the outer side;

arranging a first hydrophobic layer on the first electrode, wherein the first hydrophobic layer is a discrete coating layer positioned on the surface of the semiconductor light-emitting layer;

and the semiconductor light emitting layer contacted with the first hydrophobic layer is supported by the first hydrophobic layer and is kept complete to form a plurality of mutually independent micro LEDs.

4. The manufacturing method according to claim 1, wherein: the first hydrophobic layer is made up of a plurality of dots, particles or blocks separated from each other.

5. The manufacturing method according to claim 1, wherein: the polar liquid is water.

6. The manufacturing method according to claim 1, wherein: in the first step, a micro LED is incorporated into a polar liquid containing fine bubbles so that the micro LED adheres to the liquid surface.

7. The manufacturing method according to claim 1, wherein: the first hydrophobic layer has a density less than the polar liquid.

8. The manufacturing method according to claim 7, wherein: the first hydrophobic layer is a discrete coating of polyethylene or polypropylene.

9. The manufacturing method according to claim 1, wherein: the overall average density of the micro-LEDs is less than the polar liquid.

10. The manufacturing method as set forth in claim 9, wherein: the first hydrophobic layer is a discrete covering layer of polyethylene or polypropylene, and the volume of the first hydrophobic layer is more than 60 times of that of the semiconductor light emitting layer.

11. The manufacturing method according to claim 1, wherein: the width of the bonding pad is more than 1.2 times of the size of the micro LED.

12. The manufacturing method of claim 1, wherein the manufacturing method of the driving substrate comprises:

arranging a driving circuit layer on the first surface of the glass substrate, wherein the driving circuit layer comprises a plurality of bonding pads and a driving circuit connected to the bonding pads, and the surface of each bonding pad is provided with a second bonding layer; and the number of the first and second groups,

and a second water-repellent layer is further arranged on the surface of the driving circuit layer, and the second water-repellent layer is left empty at the bonding pad.

13. The manufacturing method according to claim 1, wherein: the second hydrophobic layer is a coating or plating layer of polyethylene or polypropylene.

14. The manufacturing method according to claim 1, wherein: in the third step, the first hydrophobic layer and the second hydrophobic layer are fused into a continuous film layer covering the surfaces of the driving circuit layer and the micro LED by using the high temperature of reflow soldering; and in the fourth step, directly tearing off the continuous film layer from the surfaces of the driving circuit layer and the micro LED.