CN114765118A

CN114765118A - Chip transfer method, wafer and transfer head for grabbing chips

Info

Publication number: CN114765118A
Application number: CN202110053476.1A
Authority: CN
Inventors: 曹轩; 龙浩晖
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-01-15
Filing date: 2021-01-15
Publication date: 2022-07-19
Also published as: WO2022151886A1

Abstract

The application provides a transfer method of a Micro-LED chip, a wafer and a transfer head for grabbing the chip, wherein the Micro-LED chip is provided with a hydrophobic layer, and the method comprises the following steps: placing a plurality of Micro-LED chips with hydrophobic layers in an aqueous solution; grabbing a plurality of Micro-LED chips in the aqueous solution through a transfer head, wherein the transfer head comprises a plurality of grooves for accommodating the Micro-LED chips, and hydrophilic layers are arranged at the bottoms of the grooves so as to enable the grabbed hydrophobic layers of the Micro-LED chips to be far away from the bottoms of the grooves; and fixing the plurality of grabbed Micro-LED chips on a target substrate, and attaching the hydrophobic layers of the Micro-LED chips to the target substrate. The fluid self-assembly method can realize the transfer of a huge amount of Micro-LED chips with high efficiency.

Description

Chip transfer method, wafer and transfer head for grabbing chips

Technical Field

The application relates to the technical field of display, in particular to a Micro-LED chip transfer method and device.

Background

In the existing display panel, the Micro-light emitting diode Micro-LED display panel has better color gamut, contrast, brightness, efficiency, reliability, service life and other performances. Therefore, the Micro-LED display panel is considered as a next generation display panel.

In the production and preparation of the Micro-LED display panel, the driving back plate for driving the Micro-LED chip and the Micro-LED are prepared on different substrates, so that the Micro-LED chip is required to be assembled on the driving back plate. For example, a huge number of Micro-LED chips can be assembled onto the driving backplane using a huge number of transfer techniques, such as elastomeric stamp pick-up transfer techniques. However, in the process of transferring the Micro-LED by the elastomeric stamp pick-up transfer technology, the transfer head is in direct contact with the Micro-LED chip and the driving substrate, and due to the different thermal expansion coefficients of the material of the transfer head and the material of the driving backplane, the transfer efficiency of the Micro-LED chip is limited by the pixel density of the Micro-LED chip and the area of the transfer head, so that the production efficiency is low and the cost is high.

Disclosure of Invention

The application provides a transfer method of Micro-LED chips, a wafer and a transfer head for grabbing the chips, wherein the transfer method can realize high-efficiency transfer of huge Micro-LED chips.

In a first aspect, a method for transferring a Micro-LED chip having a hydrophobic layer thereon is provided, the method comprising: placing a plurality of the Micro-LED chips having the hydrophobic layer in an aqueous solution; grabbing the plurality of Micro-LED chips in the aqueous solution through a transfer head, wherein the transfer head comprises a plurality of grooves for accommodating the Micro-LED chips, and hydrophilic layers are arranged at the bottoms of the grooves, so that the grabbed hydrophobic layers of the Micro-LED chips are far away from the bottoms of the grooves; and fixing the plurality of the Micro-LED chips to a target substrate, wherein the hydrophobic layer of each Micro-LED chip is attached to the target substrate.

In the Micro-LED chip transfer method, due to the existence of the hydrophobic layer on the Micro-LED chip, the existence of the groove of the transfer head and the existence of the hydrophilic layer of the groove of the transfer head, the transfer head can grab a plurality of Micro-LED chips in the aqueous solution into the groove of the transfer head, so that the self-assembly of the Micro-LED chips and the transfer head can be realized through the aqueous solution, the rapid assembly of the large-area transfer head and the Micro-LED chips is further realized, and the transfer efficiency of the Micro-LED chips is improved.

With reference to the first aspect, in certain implementations of the first aspect, before the placing the plurality of Micro-LED chips having the hydrophobic layer in an aqueous solution, the method further includes: preparing a plurality of Micro-LED chips on a wafer; preparing the hydrophobic layer on one side of the Micro-LED chip far away from the wafer; and peeling the Micro-LED chips from the wafer.

Illustratively, a plurality of vertical Micro-LED chips are epitaxially etched on a wafer.

With reference to the first aspect, in certain implementations of the first aspect, the peeling between the plurality of Micro-LED chips and the wafer includes: and irradiating laser from one side of the wafer far away from the Micro-LED chips to strip the Micro-LED chips and the wafer.

With reference to the first aspect, in certain implementations of the first aspect, before the peeling between the plurality of Micro-LED chips and the wafer, the method further includes: carrying out dead pixel detection on each Micro-LED chip in the plurality of Micro-LED chips to obtain dead pixel Micro-LED chips; the peeling between the plurality of Micro-LED chips and the wafer comprises: and according to the dead point Micro-LED chips, peeling the Micro-LED chips except the dead point Micro-LED chips in the plurality of Micro-LED chips from the wafer.

Wherein, the dead-point Micro-LED chip can be understood as that the Micro-LED chip is not bright under the condition of being electrified. And/or under the condition that the Micro-LED chip is electrified, the brightness of the Micro-LED chip and/or the wavelength of light emitted by the Micro-LED chip do not meet the required specification.

The method comprises the steps of carrying out dead pixel detection on each Micro-LED chip in a plurality of Micro-LED chips to obtain dead pixel Micro-LED chips, and peeling the Micro-LED chips except the dead pixel Micro-LED chips in the plurality of Micro-LED chips from a wafer, so that only good Micro-LED chips on the wafer can be transferred, and the Micro-LED chips with high qualified rate can be obtained.

With reference to the first aspect, in some implementations of the first aspect, the peeling off, according to the dead Micro-LED chips, the Micro-LED chips other than the dead Micro-LED chips from the wafer includes: determining a region to be irradiated according to the dead pixel Micro-LED chip, wherein the region to be irradiated is a region on the wafer except for a region occupied by the dead pixel Micro-LED chip; and in the to-be-irradiated area, irradiating laser from one side of the wafer far away from the Micro-LED chips so as to strip the Micro-LED chips except the dead Micro-LED chips from the wafer.

With reference to the first aspect, in certain implementations of the first aspect, before the peeling between the plurality of Micro-LED chips and the wafer, the method further includes: placing the wafer over the aqueous solution such that the plurality of Micro-LED chips having the hydrophobic layer are placed in the aqueous solution after the peeling between the plurality of Micro-LED chips and the wafer, wherein the hydrophobic layer faces the aqueous solution and the wafer faces away from the aqueous solution.

Wherein the wafer is placed above the aqueous solution may be understood as the wafer being directly above or obliquely above the aqueous solution, etc.

In addition, the included angle between the wafer and the aqueous solution is between 0 and 90 degrees.

After the good Micro-LED chips are peeled off from the wafer and fall into the aqueous solution, a plurality of good Micro-LED chips are densely arranged in the aqueous solution.

With reference to the first aspect, in certain implementations of the first aspect, before the grabbing, by a transfer head, the plurality of Micro-LED chips in the aqueous solution, the method further includes: stirring the plurality of Micro-LED chips in the aqueous solution.

In some embodiments, the plurality of good Micro-LED chips in the aqueous solution are stirred for a fixed period of time.

A plurality of good Micro-LED chips in the aqueous solution are stirred, so that the colors displayed by the plurality of good Micro-LED chips are free from color difference as much as possible, and wavelength bins can be avoided.

With reference to the first aspect, in certain implementations of the first aspect, the grasping, by a transfer head, a plurality of the Micro-LED chips in the aqueous solution includes: placing the transfer head under a plurality of the Micro-LED chips with the grooves of the transfer head facing the Micro-LED chips; and moving the transfer head out of the aqueous solution to grab a plurality of the Micro-LED chips.

Wherein removing the transfer head from the aqueous solution may be removing the transfer head from the aqueous solution in a direction that forms a first angle with the horizontal. Wherein the first angle is greater than 0 ° and less than 90 °.

In some embodiments, before said grasping a plurality of said Micro-LED chips in said aqueous solution by a transfer head, said method further comprises: the transfer head is prepared.

In one implementable manner, the production transfer head comprises: preparing a transparent layer on a glass substrate; preparing a high polymer material array layer on one side of the transparent layer far away from the glass substrate, wherein the high polymer material array layer comprises a plurality of high polymer material layers, and the grooves are formed on the adjacent high polymer material layers.

With reference to the first aspect, in certain implementations of the first aspect, the fixing the grabbed plurality of Micro-LED chips onto a target substrate includes: placing the transfer head over the target substrate with the hydrophobic layer of the Micro-LED chip facing toward the target substrate and the Micro-LED chip facing away from the target substrate; and irradiating laser from one side of the transfer head far away from the target substrate, and peeling between the transfer head and the hydrophilic layer so as to peel the plurality of the Micro-LED chips which are grabbed off the transfer head and fix the Micro-LED chips on the target substrate.

With reference to the first aspect, in certain implementations of the first aspect, the target substrate includes an adhesive layer and a driving back plate, which are stacked, and the adhesive layer is used to fix the Micro-LED chips to the target substrate.

With reference to the first aspect, in certain implementations of the first aspect, after the fixing the grabbed plurality of Micro-LED chips onto a target substrate, the method further includes: and heating the target substrate, and removing the hydrophobic layer of the Micro-LED chip.

With reference to the first aspect, in certain implementation manners of the first aspect, the Micro-LED chip further has a first electrode layer disposed between the Micro-LED chip and the hydrophobic layer.

For example, a first electrode may be evaporated on a side of each Micro-LED chip away from the wafer to form a first electrode layer.

In some embodiments, the first electrode of the first electrode layer is a P-pole.

With reference to the first aspect, in certain implementations of the first aspect, after the fixing the grabbed plurality of Micro-LED chips onto the target substrate, the method further includes: and preparing a second electrode layer on one side of the Micro-LED chip far away from the target substrate.

In some embodiments, the second electrode of the second electrode layer is an N-pole.

With reference to the first aspect, in certain implementations of the first aspect, the transfer head further includes: a glass substrate; a transparent layer disposed on the glass substrate; the high polymer material array layer is arranged on one side, away from the glass substrate, of the transparent layer and comprises a plurality of high polymer material layers, and the grooves are formed between the adjacent high polymer material layers; and under the condition that the side of the transfer head far away from the Micro-LED chips is irradiated by laser, peeling between the transparent layer and the hydrophilic layer so as to enable the grabbed plurality of Micro-LED chips to peel off the transfer head and be fixed to the target substrate.

For example, the material of the transparent layer may be triazene, polyimide PI, benzocyclobutene BCB, or the like.

For example, the material of the polymer material layer may be a hydrophobic polymer material, a material composed of silicon dioxide and hexamethyldisilazane HMDS, or the like.

With reference to the first aspect, in certain implementations of the first aspect, the material of the hydrophobic layer is a self-assembled thin film SAM.

In a second aspect, a wafer is provided, the wafer includes Micro light emitting diode Micro-LED chips, and a hydrophobic layer is provided on a side of the Micro-LED chips far away from the wafer.

And arranging a hydrophobic layer on one side of the Micro-LED chip far away from the wafer, so that the self-assembly of the Micro-LED chip and the transfer head can be realized through the aqueous solution.

With reference to the second aspect, in certain implementations of the second aspect, the Micro-LED chips and the wafer are peeled off from each other when a side of the wafer remote from the Micro-LED chips is irradiated with laser light.

With reference to the second aspect, in certain implementation manners of the second aspect, the Micro-LED chip further has a first electrode layer disposed between the Micro-LED chip and the hydrophobic layer.

With reference to the second aspect, in certain implementations of the second aspect, the material of the hydrophobic layer is a self-assembled thin film SAM.

In a third aspect, a transfer head for grasping a Micro-LED chip having a hydrophobic layer thereon is provided, the transfer head comprising: the groove is used for accommodating the Micro-LED chip, and a hydrophilic layer is arranged at the bottom of the groove, so that the hydrophobic layer of the grabbed Micro-LED chip is far away from the bottom of the groove.

Due to the existence of the groove of the transfer head and the existence of the hydrophilic layer of the groove of the transfer head, the transfer head can grab a plurality of Micro-LED chips in the aqueous solution into the groove of the transfer head, so that the self-assembly of the Micro-LED chips and the transfer head can be realized through the aqueous solution, the rapid assembly of the large-area transfer head and the Micro-LED chips is further realized, and the transfer efficiency of the Micro-LED chips is improved.

With reference to the third aspect, in certain implementations of the third aspect, the transfer head further includes: a glass substrate; a transparent layer disposed on the glass substrate; the high polymer material array layer is arranged on one side, away from the glass substrate, of the transparent layer and comprises a plurality of high polymer material layers, and the grooves are formed between the adjacent high polymer material layers.

With reference to the third aspect, in certain implementations of the third aspect, in a case where a side of the transfer head away from the groove is irradiated with laser light, the transparent layer and the hydrophilic layer are peeled off, so that the grabbed plurality of Micro-LED chips are peeled off the transfer head.

In a fourth aspect, there is provided an apparatus having functionality to implement any one of the above first aspect and certain implementations of the first aspect. The functions may be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above-described functions.

In a fifth aspect, an apparatus is provided that includes one or more processors; one or more memories; the one or more memories store one or more computer programs comprising instructions that, when executed by the one or more processors, cause the apparatus to perform the method of transferring Micro-LED chips in any of the above first aspect and certain implementations of the first aspect.

A sixth aspect provides a storage medium having stored thereon a computer program or instructions that, when executed, cause a computer to perform the method of transferring a Micro-LED chip in any one of the above first aspect and certain implementations of the first aspect.

In a seventh aspect, a chip system is provided, including: a processor configured to perform the method for transferring the Micro-LED chip in the first aspect as well as in any of some implementations of the first aspect.

Drawings

FIG. 1 is a schematic radar plot of multiple properties of different display panels.

FIGS. 2 and 3 are schematic diagrams illustrating an example of a mass transfer technique for Micro-LED chips.

FIG. 4 is a schematic diagram of another example of a bulk transfer technique for Micro-LED chips.

FIG. 5 is a schematic flowchart of an example of a mass transfer method for Micro-LED chips according to an embodiment of the present disclosure.

Fig. 6 to 10 are schematic views illustrating the transfer of the Micro-LED chip from the wafer according to the embodiment of the present application.

Fig. 11 is a schematic view of an example of bad pixels and wavelength uniformity in a Micro-LED chip according to an embodiment of the present disclosure.

Fig. 12 is a schematic structural diagram of an example of a transfer head according to an embodiment of the present application.

Fig. 13 and 14 are schematic diagrams illustrating a transfer head transferring a huge number of Micro-LED chips according to an embodiment of the present disclosure.

Fig. 15 is a schematic structural diagram of an example of a target substrate according to an embodiment of the present application.

Fig. 16 to 18 are schematic views illustrating an example of transferring a Micro-LED chip to a target substrate according to an embodiment of the present disclosure.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings in the following embodiments of the present application.

References to "width," "upper," "lower," "horizontal," "bottom," and the like in embodiments of the present application are made to the orientation or positional relationship shown in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the invention.

The embodiments of the present application relate to at least one, including one or more; wherein a plurality means greater than or equal to two. In addition, it is to be understood that the terms first, second, etc. in the description of the present application are used for distinguishing between the descriptions and not necessarily for describing a sequential or chronological order.

The terminology used in the following examples is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of this application and the appended claims, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, such as "one or more", unless the context clearly indicates otherwise. It should also be understood that in the embodiments of the present application, "one or more" means one, two or more; "and/or" describes the association relationship of the associated objects, indicating that three relationships may exist; for example, a and/or B, may represent: a alone, both A and B, and B alone, where A, B may be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather "one or more but not all embodiments" unless specifically stated otherwise. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless otherwise specifically stated.

Through the embodiments of the present applicationThe display panel prepared by the method can be applied to electronic equipment, and the electronic equipment can include mobile phones, tablet computers, wearable equipment, televisions, vehicle-mounted equipment, Augmented Reality (AR)/Virtual Reality (VR) equipment, notebook computers, ultra-mobile personal computers (UMPCs), netbooks, Personal Digital Assistants (PDAs), and other electronic equipment, and the embodiment of the present application does not set any limit to the specific type of the electronic equipment. Exemplary embodiments of the electronic device include, but are not limited to, a mount

Or other operating system.

The display panel may adopt a Liquid Crystal Display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (active-matrix organic light-emitting diode, AMOLED), a flexible light-emitting diode (FLED), a Mini-LED, a Micro-OLED, a quantum dot light-emitting diode (QLED), and the like.

For example, FIG. 1 is a schematic radar plot of multiple properties of different display panels. As shown in fig. 1, among LCD display panels, OLED display panels, Micro-LED display panels, and QLED display panels, the Micro-LED display panels are superior in color gamut, contrast, brightness, efficiency, reliability, and life span performance. Therefore, the Micro-LED display panel is considered as a next generation display panel.

In the production and preparation of the Micro-LED chip, the driving back plate for driving the Micro-LED chip and the Micro-LED chip are prepared on different substrates, so the Micro-LED chip is required to be assembled on the driving back plate. For example, a bulk transfer technique may be employed to assemble a bulk of Micro-LED chips onto a driving backplane. The huge amount is used to indicate that the number is huge.

For example, a huge number of Micro-LED chips can be assembled onto a driving backplane by a huge number of transfer techniques based on van der waals forces.

In the prior art, bulk transfer techniques include the stamp pick and place (stamp pick and place) technique and the laser beam splitting array technique.

For example, FIG. 2 is a schematic diagram of the assembly of a huge number of Micro-LED chips onto a driving backplane based on the elastomeric stamp pick-and-transfer technique. The flexible stamp picking and transferring technology is to use the flexible stamp and combine with a high-precision motion control transfer head, and to take the Micro-LED 101, the Micro-LED 102 and the Micro-LED 103 which are epitaxially grown away from the respective wafers respectively by van der Waals force or high polymer adhesion force, and to adhere the wafers to the transfer head.

For example, fig. 3 is a schematic diagram of a transfer head assembling a huge amount of Micro-LED chips onto a driving backplane. As shown in fig. 3, the Micro-LED array 110 is placed on the driving backplane 120 by the transfer head 140 to form the display panel 130. The driving backplane 120 may be a Thin Film Transistor (TFT).

In the process of transferring the Micro-LED by the flexible stamp picking and transferring technology, the transfer head is respectively in direct contact with the Micro-LED chip and the driving substrate, and the transfer efficiency of the Micro-LED chip is limited by the pixel density of the Micro-LED chip and the area of the transfer head due to the fact that the material of the transfer head and the material of the driving back plate have different thermal expansion coefficients, so that the production efficiency is low, and the cost is high.

For example, fig. 4 is a schematic diagram of a huge transfer technology based on a laser beam splitting array technology, and a huge Micro-LED chip is assembled on a driving backplane. The laser beam 210 rapidly transfers a large number of Micro-LEDs on the substrate 230 through a mask 220 onto a driving back plane 240.

In the process of transferring the Micro-LED chip by the laser beam splitting array technology, the dead pixel and the wavelength consistency of the Micro-LED chip are difficult to select, and the yield is low in the mass production process.

Therefore, the application provides a transfer method of the Micro-LED chips, and the transfer of huge Micro-LED chips with high efficiency and high qualified rate can be realized through the method.

Hereinafter, a transferring method 300 of Micro-LED chips provided in an embodiment of the present application is described with reference to fig. 5 to 18.

For example, fig. 5 is a schematic flowchart of a transferring method 300 for Micro-LED chips according to an embodiment of the present disclosure. As shown in fig. 5, the method 300 includes:

s301, preparing a Micro-LED chip array layer on the wafer.

Specifically, a plurality of vertical Micro-LED chips are epitaxially etched on a wafer, and the Micro-LED chips form a Micro-LED chip array layer.

Illustratively, the material of the wafer may be sapphire, silicon, or the like.

The shape of the wafer is not limited in the embodiments of the present application.

The arrangement mode of the plurality of Micro-LED chips in the Micro-LED chip array layer is not limited in the embodiment of the application.

For example, as shown in FIG. 6, a vertical array layer 402 of Micro-LED chips is epitaxially etched on a wafer 401. The Micro-LED chip array layer 402 includes 4 Micro-LED chips, namely a Micro-LED chip 4021, a Micro-LED chip 4022, a Micro-LED chip 4023, and a Micro-LED chip 4024.

S302, preparing a first electrode array layer on one side, far away from the wafer, of the Micro-LED chip array layer.

For example, a first electrode is evaporated on the side of each Micro-LED chip away from the wafer. Namely, one Micro-LED chip corresponds to one first electrode, and the plurality of first electrodes form a first electrode array layer.

For example, as shown in fig. 7, a first electrode array layer 403 is prepared on the side of the Micro-LED chip array layer 402 away from the wafer 401. Specifically, a first electrode 4031 is evaporated on a side of the Micro-LED chip 4021 away from the wafer 401, a first electrode 4032 is evaporated on a side of the Micro-LED chip 4022 away from the wafer 401, a first electrode 4033 is evaporated on a side of the Micro-LED chip 4023 away from the wafer 401, and a first electrode 4034 is evaporated on a side of the Micro-LED chip 4024 away from the wafer 401. The first electrode 4031, the first electrode 4032, and the first electrode 4033 form the first electrode array layer 403.

S303, performing dead pixel detection on each Micro-LED chip in the Micro-LED chip array layer to obtain dead pixel Micro-LED chips in the Micro-LED chip array layer.

In the embodiment of the application, the dead Micro-LED chip can be understood as that the Micro-LED chip is not bright under the condition of being electrified. And/or under the condition that the Micro-LED chip is electrified, the brightness of the Micro-LED chip and/or the wavelength of light emitted by the Micro-LED chip do not meet the requirement specification.

The embodiment of the present application does not limit the method for detecting the dead pixel.

Illustratively, each Micro-LED may be dead-spot detected based on Electroluminescence (EL) detection.

For example, the principle of the EL detection may be to perform a dead-spot detection on the Micro-LED chip by turning on the Micro-LED chip through the probe and applying a current to the Micro-LED chip.

For another example, the principle of EL detection may be to inductively light up the Micro-LED chip by a non-contact electromagnetic field, thereby performing dead-spot detection on the Micro-LED chip.

Illustratively, each Micro-LED may be dead-spot detected based on Photoluminescence (PL) detection and Automated Optical Identification (AOI) systems.

For example, the principle of PL detection may be to detect a dead spot of a Micro-LED chip by light emission of a laser semiconductor itself.

As another example, the principle of AOI detection may be to perform dead pixel detection on Micro-LED chips by optical observation.

For example, as shown in fig. 7, after performing bad dot detection on 4 Micro-LED chips, namely, Micro-LED chip 4021, Micro-LED chip 4022, Micro-LED chip 4023, and Micro-LED chip 4024, it is found that Micro-LED chip 4022 is a bad dot Micro-LED chip, and Micro-LED chip 4021, Micro-LED chip 4023, and Micro-LED chip 4024 are good Micro-LED chips. Wherein, good Micro-LED chips can be understood as non-defective Micro-LED chips.

The above-mentioned S303 may or may not be executed, and the present application does not limit this.

S304, preparing a hydrophobic array layer on the side, away from the Micro-LED array layer, of the first electrode array layer.

For example, a hydrophobic layer is prepared for each first electrode on the side away from the Micro-LED, i.e. one first electrode corresponds to one hydrophobic layer, and the plurality of hydrophobic layers form a hydrophobic array layer.

Illustratively, the material of the hydrophobic array layer may be a self-assembled film (SAM).

For example, as shown in FIG. 8, a hydrophobic array layer 404 is prepared on the side of the first electrode array layer 403 away from the Micro-LED array layer 402. Specifically, a hydrophobic layer 4041 is prepared on a side of the first electrode 4031 away from the Micro-LED array layer 402, a hydrophobic layer 4042 is prepared on a side of the first electrode 4032 away from the Micro-LED array layer 402, a hydrophobic layer 4043 is prepared on a side of the first electrode 4033 away from the Micro-LED array layer 402, and a hydrophobic layer 4044 is prepared on a side of the first electrode 4034 away from the Micro-LED array layer 402. The hydrophobic layer 4041, hydrophobic layer 4042, hydrophobic layer 4043, and hydrophobic layer 4044 form the hydrophobic array layer 404.

In the above, through S301 to S304, a process flow of preparing a plurality of Micro-LED chips on a wafer, and a first electrode layer of each Micro-LED chip and a hydrophobic layer of each Micro-LED chip is described. Hereinafter, a process flow of peeling between the wafer and the plurality of Micro-LED chips will be described through S305.

In the present embodiment, the plurality of Micro-LED chips may be understood as a bulk Micro-LED chip.

S305, peeling the Micro-LED chip and the wafer.

For example, good Micro-LED chips can be peeled off in an aqueous solution by using a Laser Lift Off (LLO) technique.

In some embodiments, if the above S303 is not performed, all the Micro-LED chips on the wafer need to be peeled off from the wafer. Specifically, the wafer obtained after S304 is moved to the upper part of the aqueous solution, laser is irradiated from one side of the wafer far away from the Micro-LED chip, and the Micro-LED chip and the wafer are stripped due to the fact that the laser energy decomposes the GaN buffer layer of the gallium nitride at the interface of the wafer and the Micro-LED chip.

In other embodiments, if the step S303 is executed, the Micro-LED chips except the defective Micro-LED chip on the wafer need to be peeled from the wafer, that is, the good Micro-LED chips on the plurality of Micro-LED chips on the wafer are peeled from the wafer.

Therefore, according to the Micro-LED chips with the dead spots, the Micro-LED chips except the Micro-LED chips with the dead spots in the plurality of Micro-LED chips can be peeled from the wafer, and the good Micro-LED chips can be peeled from the wafer.

In an implementation mode, according to defective Micro-LED chips, determining an area (marked as an area to be irradiated for convenience of description) occupied by each good Micro-LED chip on a wafer, irradiating laser from one side of the wafer far away from the Micro-LED chips in the area to be irradiated, and decomposing a gallium nitride GaN buffer layer at an interface of the wafer and each good Micro-LED chip by the laser energy, so that the good Micro-LED chips in the plurality of Micro-LED chips on the wafer are peeled from the wafer.

The area to be irradiated can be subjected to contour graph determination through a corresponding positioning system. In the to-be-irradiated area, the laser is irradiated from the side of the wafer far away from the Micro-LED chip, which is understood to be the laser irradiated from the side of the wafer far away from the Micro-LED chip in the outline pattern corresponding to the to-be-irradiated area.

In another realizable mode, determining the area occupied by each defective Micro-LED chip on the wafer according to the defective Micro-LED chips, irradiating laser from one side of the wafer far away from the Micro-LED chips in the area except the area occupied by the defective Micro-LED chips on the wafer, and realizing the stripping between the good Micro-LED chips and the wafer in the plurality of Micro-LED chips on the wafer due to the fact that the laser energy decomposes the gallium nitride GaN buffer layer at the interface of the wafer and each good Micro-LED chip.

S306, placing a plurality of Micro-LED chips with hydrophobic layers and first electrodes in an aqueous solution.

In some embodiments, the plurality of Micro-LED chips with the hydrophobic layer and the first electrode obtained in S305 may be directly placed in an aqueous solution.

In other embodiments, before S305, i.e., before peeling the Micro-LED chip and the wafer, the wafer obtained after S304 needs to be placed above the aqueous solution, wherein the hydrophobic layer of the Micro-LED chip faces the aqueous solution, and the wafer faces away from the aqueous solution; peeling the Micro-LED chip and the wafer (S305); after the Micro-LED chips and the wafer are peeled off, the Micro-LED chips fall into the aqueous solution below, and a plurality of Micro-LED chips having hydrophobic layers and first electrodes are placed in the aqueous solution (S306).

For example, as shown in fig. 9, the wafer 401 prepared after S304 is moved to a position right above the aqueous solution 405, and only the areas irradiated by the good Micro-LED chips (the Micro-LED chips 4021, the Micro-LED chips 4022, and the Micro-LED chips 4023) are irradiated with laser light from a side of the wafer 401 away from the aqueous solution 405, and the laser energy decomposes the GaN buffer layer at the interfaces between the wafer 401 and the good

Micro-LED chips

4021, 4022, and 4023, respectively, thereby achieving peeling between the good Micro-LED chips and the wafer 401.

Thus, good Micro-LED chips will fall into the aqueous solution 405. For example, as shown in FIG. 10, the Micro-LED chip 410, the Micro-LED chip 430, and the Micro-LED chip 440 fall into the aqueous solution 405. The Micro-LED chips 420 are still on the wafer 401. Due to the existence of the hydrophobic layer of the Micro-LED chip, the Micro-LED chip is sequentially provided with the hydrophobic layer, the first electrode layer and the Micro-LED chip along the depth direction of the aqueous solution after falling into the aqueous solution.

After the good product Micro-LED chips are peeled off the wafer and fall into the aqueous solution, the good product Micro-LED chips are densely arranged in the aqueous solution, and at the moment, the good product Micro-LED chips in the aqueous solution can be stirred, so that the colors displayed by the whole good product Micro-LED chips are free of chromatic aberration as far as possible, and wavelength bin splitting can be avoided.

For example, as shown in the left side of fig. 11, since the Micro-LEDs on each of the

wafers

251, 252, 253, and 254 have different purities of emitted light, the Micro-LEDs of 3 display colors are respectively included on each wafer, and thus there are wavelength bins. In addition, a dead Micro-LED is present on each wafer, for example, a Micro-LED with a black dot is a dead Micro-LED.

After the steps from S301 to S305, only good Micro-LEDs can be transferred into the aqueous solution, so that Micro-LED chips with high yield can be obtained.

If the plurality of Micro-LED chips in the aqueous solution are uniformly stirred, as shown in the right-hand diagram of fig. 11, the Micro-LED chips in the aqueous solution can uniformly display 1 color in a certain region, and there is no problem of wavelength bins like the color displayed by the Micro-LEDs on the wafer as shown in the left-hand diagram of fig. 11, so that the wavelength bins can be avoided.

Hereinafter, a process flow of picking up the plurality of Micro-LED chips of the delaminated wafer from the transfer head will be described through S306 to S307.

S307, grabbing the Micro-LED chip in the water solution through the transfer head.

In S307, a transfer head is required to be available. Wherein a usable transfer head is understood to be a Micro-LED chip that the transfer head can grab into an aqueous solution.

In some embodiments, prior to S307, if a transfer head is available, there is no need to prepare a transfer head.

In other embodiments, before S307, if there is no transfer head available, a transfer head needs to be prepared. Wherein, a non-usable transfer head is understood to be a Micro-LED chip that can be grasped in an aqueous solution without a transfer head.

Specifically, a transparent layer is prepared on a glass substrate, and a high polymer material array layer is prepared on one side, far away from the glass substrate, of the transparent layer, the high polymer material array layer comprises a plurality of high polymer material layers, adjacent high polymer material layers form a groove, and the groove is used for containing Micro-LED chips in aqueous solution.

When laser is irradiated on the transparent layer, the bonding of the substance directly contacting with the transparent layer can be released, namely, the separation of the transparent layer and the substance directly contacting with the transparent layer is realized.

Illustratively, a transparent material may be ablated or bonded onto a glass substrate to form a transparent layer.

For example, the polymer material may be coated on the transparent layer every predetermined distance to form the polymer material array layer. Wherein the predetermined distance is the same as or similar to the width of the groove 504.

For example, a polymer material may be coated on the transparent layer, and a plurality of grooves may be formed on the layer formed by the polymer material by photolithography or etching, and a polymer material layer may be formed between adjacent grooves, and the plurality of polymer material layers may form a polymer array.

For example, the material of the polymer material layer may be hydrophobic polymer material, material composed of silicon dioxide and hexamethyldisilazane HMDS, or the like.

For example, as shown in fig. 12, the transfer head 500 may be sequentially stacked by a glass substrate 501, a transparent layer 502, and a polymer material array layer 503. The polymer material array layer 503 includes 4 polymer material layers, i.e., a polymer material layer 5031, a polymer material layer 5032, a polymer material layer 5033, and a polymer material layer 5044. The 4 polymer material layers can form 3 recesses, that is, the polymer material layer 5031 and the polymer material layer 5032 form the recess 5041, the polymer material layer 5032 and the polymer material layer 5033 form the recess 5042, and the polymer material layer 5033 and the polymer material layer 5034 form the recess 5043.

After the transfer head is available, it is necessary to prepare a hydrophilic layer at the bottom of the groove of the available transfer head. The hydrophilic layer can enable the hydrophobic layer of the grabbed Micro-LED chip to be accommodated in the groove far away from the bottom of the groove when the transfer head grabs the Micro-LED chip in the aqueous solution.

The material of the hydrophilic layer is not limited in the embodiments of the present application.

For example, the material of the hydrophilic layer is an oxide. For another example, the hydrophilic layer is made of a polymer film.

For example, as shown in fig. 12, the bottom of the groove 504 is prepared with a hydrophilic layer 505. Specifically, the bottom of recess 5041 is prepared with hydrophilic layer 5051, the bottom of recess 5042 is prepared with hydrophilic layer 5052, and the bottom of recess 5043 is prepared with hydrophilic layer 5053.

After preparing the hydrophilic layer at the bottom of the groove of the transfer head, S306 is performed.

Specifically, the transfer head can be placed below the Micro-LED chip, the groove of the transfer head faces the Micro-LED chip in the aqueous solution, and the transfer head is moved out of the aqueous solution by a pulling method to grab the Micro-LED chip in the aqueous solution.

Removing the transfer head from the aqueous solution may be removing the transfer head from the aqueous solution in a direction at a first angle to the horizontal. Wherein the first angle is greater than 0 ° and less than 90 °.

Specifically, as shown in fig. 13, the transfer head 500 may be placed under the Micro-LED chip 410, the Micro-LED chip 430 and/or the Micro-LED chip 440, the groove 504 of the transfer head 500 faces the Micro-LED chip, and the transfer head 500 is moved out of the aqueous solution by using a pulling method to grab the Micro-LED chip 410, the Micro-LED chip 430 and/or the Micro-LED chip 440 in the aqueous solution 405.

In the process of lifting the transfer head, due to the existence of the hydrophobic layer of the Micro-LED chip, the existence of the groove of the transfer head and the existence of the hydrophilic layer of the groove of the transfer head, the grabbed Micro-LED chip can be accommodated in the groove of the transfer head, and in the groove, the hydrophobic layer of the Micro-LED chip is far away from the bottom of the groove, so that the Micro-LED chip in the water solution can be grabbed through the transfer head.

The rapid assembly of the large-area transfer head can be realized by adopting a fluid (aqueous solution) self-assembly mode, namely, the transfer process of transferring the Micro-LED chip from the transfer head to the target substrate is realized by adopting a non-contact printing mode, the limitation of the heating and pressurizing and Coefficient of Thermal Expansion (CTE) problems to large-area transfer in the sticking process is avoided, and the transfer efficiency of the Micro-LED chip is improved.

For example, as shown in FIG. 14, a transfer head 500 for grasping the Micro-LED chip 410, the Micro-LED chip 430 and the Micro-LED chip 440 is provided.

Hereinafter, a process flow of fixing the plurality of Micro-LED chips grasped by the transfer head to the target substrate will be described through S308.

S308, fixing the grabbed Micro-LED chip on a target substrate.

Specifically, a transfer head is placed above a target substrate, wherein a hydrophobic layer of a Micro-LED chip on the transfer head faces the target substrate, and the Micro-LED chip faces away from the target substrate; and irradiating laser from one side of the transfer head far away from the target substrate, wherein the laser reaches the transparent layer, the bonding of the hydrophilic layer in direct contact with the transparent layer can be released, namely, the peeling between the transparent layer and the hydrophilic layer is realized, so that the plurality of grabbed Micro-LED chips peel off the transfer head and are fixed on the target substrate, and at the moment, the hydrophobic layer of each Micro-LED chip in the plurality of Micro-LED chips is attached to the target substrate.

For example, as shown in fig. 15, the target substrate 600 may be stacked by a driving back plate 602 and an adhesive layer 601. The plurality of Micro-LED chips may be fixed to the target substrate by an adhesive layer.

For example, the driving backplane may be a TFT substrate.

The adhesive layer is an adhesive material having adhesiveness. For example, the material used for the adhesive layer may be Anisotropic Conductive Film (ACF).

Specifically, as shown in fig. 16, the transfer head 500 that captures the Micro-LED chip 410, the Micro-LED chip 430, and the Micro-LED chip 440 is moved to above the target substrate 600, at this time, the hydrophobic layer of the Micro-LED chip faces the target substrate 600, the Micro-LED chip faces away from the target substrate, and the adhesive layer 601 of the target substrate 600 is between the transfer head 500 and the driving substrate 602. By partially scanning the area on the glass substrate 401 corresponding to the Micro-LED chip 410, the area on the glass substrate 401 corresponding to the Micro-LED chip 430, and the area on the glass substrate 401 corresponding to the Micro-LED chip 440 from the side of the glass substrate 401 with laser light, the laser light is irradiated on the transparent layer 502 through the glass substrate, since the Micro-LED chip 410 is accommodated in the groove 5041 of the transfer head 500 through the hydrophilic layer 5051, the Micro-LED chip 430 is accommodated in the groove 5042 of the transfer head 500 through the hydrophilic layer 5052, and the Micro-LED chip 440 is accommodated in the groove 5043 of the transfer head 500 through the hydrophilic layer 5053, and since the hydrophilic layer 5051, the hydrophilic layer 5052, the hydrophilic layer 5053, and the transparent layer 502 are in direct contact, the laser light irradiated on the transparent layer 502 can release the bonding between the transparent layer 502 and the hydrophilic layer 5051, the hydrophilic layer 5052, the hydrophilic layer 5053, and the transparent layer 502, respectively, that is, the Micro-LED chip 410, the Micro-LED chip 430, and the Micro-LED chip 440 are respectively peeled off from the transfer head 500, so that the Micro-LED chip 410 having the hydrophilic layer 5051, the Micro-LED chip 430 having the hydrophilic layer 5052, and the Micro-LED chip 440 having the hydrophilic layer 5053 are fixed to the target substrate 600. For example, as shown in fig. 17, there are a schematic structure in which a Micro-LED chip 410 having a hydrophilic layer 5051, a Micro-LED chip 430 having a hydrophilic layer 5052, and a Micro-LED chip 440 having a hydrophilic layer 5053 are attached to a target substrate 600. At this time, the hydrophobic layer 4041 of the Micro-LED chip 410, the hydrophobic layer 4043 of the Micro-LED chip 430, and the hydrophobic layer 4044 of the Micro-LED chip 440 are respectively attached to the target substrate 600.

The local scanning of the laser from one side of the glass substrate may be performed by determining a profile pattern of an area to be scanned by a corresponding positioning system, and emitting the laser in the profile pattern corresponding to the area to be scanned.

In the above steps, the process flow for transferring the huge number of Micro-LED chips from the wafer to the target substrate is completed through S301 to S308. Hereinafter, a process flow for manufacturing the display panel will be described through S309 to S310.

S309, remove the transfer head, pressurize and heat the target substrate.

In the process of pressurizing and heating the target substrate, the hydrophobic layer of the Micro-LED chip and the hydrophilic layer on the Micro-LED chip are volatilized. Meanwhile, the electric connection of each Micro-LED chip can be realized.

S310, preparing a vertical second electrode layer on one side, far away from the target substrate, of each Micro-LED chip.

In the embodiment of the present application, in the first electrode layer and the second electrode layer, the electrode of one electrode layer is an N-pole, and the electrode of the other electrode layer is a P-pole. For example, the first electrode of the first electrode layer is a P-pole, and the second electrode of the second electrode layer is an N-pole.

For example, as shown in fig. 18, a vertical second electrode layer 603 may be prepared on a side of each Micro-LED chip away from the target substrate 600 based on a process of evaporation or photolithographic coating. A vertical second electrode layer 6031 is prepared on the side of the Micro-LED chip 410 away from the target substrate 600, a vertical second electrode layer 6032 is prepared on the side of the Micro-LED chip 430 away from the target substrate 600, and a vertical second electrode layer 6033 is prepared on the side of the Micro-LED chip 440 away from the target substrate 600.

By way of introduction to the foregoing, for example, table 1 shows a comparison of some of the performance of method 300 and prior art schemes. As shown in Table 1, by the method 300, the transfer of 1 million Micro-LED chips per hour can be realized, the wavelength bin problem does not exist, and massive repair can be realized. Meanwhile, by the method 300, after the Micro-LED chips are transferred from the wafer to the target substrate, the formed display panel can be applied to all electronic devices.

TABLE 1

The display panel prepared after transferring a huge number of Micro-LED chips by the method 300 (for example, the schematic structural diagram shown in FIG. 18) can be applied to the Micro-LED display panel.

By the method 300, the huge transfer of the Micro-LED chips with high efficiency and high qualification rate can be realized, the large-scale mass production of the Micro-LED panels and the effective reduction of the cost can be realized, and the method can be suitable for the manufacturing process of display modules of different electronic equipment.

It should also be understood that the sequence numbers of the above processes do not mean the execution sequence, and the execution sequence of each process should be determined by the function and the inherent logic of each process, and should not constitute any limitation to the implementation process of the embodiments of the present application.

The embodiment of the application also provides equipment for transferring the Micro-LED chips. In one implementable manner, the device may perform the method 300 described above. In another implementable manner, the apparatus may comprise a plurality of devices that cooperate to perform the method 300 described above. The equipment can be called a set of production line equipment for realizing mass transfer of Micro-LED chips.

An apparatus is also provided in an embodiment of the present application, which includes one or more processors; one or more memories; the one or more memories store one or more computer programs comprising instructions that, when executed by the one or more processors, cause the apparatus to perform the above described Micro-LED chip transfer method 300.

An embodiment of the present application further provides a storage medium, where a computer program or instructions are stored on the storage medium, and when the computer program or instructions are executed, the computer is caused to execute the above transfer method 300 for the Micro-LED chip.

An embodiment of the present application further provides a chip system, including: and a processor for executing the above transferring method 300 for the Micro-LED chip.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one type of logical functional division, and other divisions may be realized in practice, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for transferring a Micro-LED chip, wherein the Micro-LED chip is provided with a hydrophobic layer, the method comprises the following steps:

placing a plurality of the Micro-LED chips having the hydrophobic layer in an aqueous solution;

grabbing a plurality of Micro-LED chips in the aqueous solution through a transfer head, wherein the transfer head comprises a plurality of grooves for accommodating the Micro-LED chips, and hydrophilic layers are arranged at the bottoms of the grooves, so that the hydrophobic layers of the grabbed Micro-LED chips are far away from the bottoms of the grooves;

and fixing the plurality of the Micro-LED chips to a target substrate, wherein the hydrophobic layer of each Micro-LED chip is attached to the target substrate.

2. The transfer method according to claim 1, wherein before said placing a plurality of said Micro-LED chips having said hydrophobic layer in an aqueous solution, said method further comprises:

preparing a plurality of Micro-LED chips on a wafer;

preparing the hydrophobic layer on one side of the Micro-LED chip far away from the wafer;

and peeling the Micro-LED chips from the wafer.

3. The transfer method as claimed in claim 2, wherein said peeling between said plurality of Micro-LED chips and said wafer comprises:

and irradiating laser from one side of the wafer far away from the Micro-LED chips to strip the Micro-LED chips and the wafer.

4. The transfer method according to claim 2, wherein prior to said peeling between said plurality of Micro-LED chips and said wafer, said method further comprises:

carrying out dead pixel detection on each Micro-LED chip in the plurality of Micro-LED chips to obtain dead pixel Micro-LED chips;

the peeling between the plurality of Micro-LED chips and the wafer comprises:

and according to the Micro-LED chips with the dead points, peeling the Micro-LED chips except the Micro-LED chips with the dead points from the wafer.

5. The transfer method according to claim 4, wherein the peeling of the Micro-LED chips except the dead Micro-LED chips from the wafer according to the dead Micro-LED chips comprises:

determining a region to be irradiated according to the dead pixel Micro-LED chip, wherein the region to be irradiated is a region on the wafer except for a region occupied by the dead pixel Micro-LED chip;

and in the area to be irradiated, irradiating laser from one side of the wafer far away from the Micro-LED chips so as to strip the Micro-LED chips except the dead Micro-LED chips from the wafer.

6. The transfer method according to any of claims 2 to 5, wherein prior to said peeling between said plurality of Micro-LED chips and said wafer, said method further comprises:

placing the wafer over the aqueous solution such that the plurality of Micro-LED chips having the hydrophobic layer are placed in the aqueous solution after the peeling between the plurality of Micro-LED chips and the wafer, wherein the hydrophobic layer faces the aqueous solution and the wafer faces away from the aqueous solution.

7. The transfer method according to any one of claims 1 to 6, wherein before said grasping a plurality of said Micro-LED chips in said aqueous solution by a transfer head, said method further comprises:

stirring the plurality of Micro-LED chips in the aqueous solution.

8. The transfer method according to any one of claims 1 to 7, wherein said grasping a plurality of said Micro-LED chips in said aqueous solution by a transfer head comprises:

placing the transfer head under a plurality of the Micro-LED chips with the grooves of the transfer head facing the Micro-LED chips;

and moving the transfer head out of the aqueous solution to grab a plurality of the Micro-LED chips.

9. The transfer method according to any one of claims 1 to 8, wherein the fixing the grasped plurality of Micro-LED chips onto a target substrate comprises:

placing the transfer head over the target substrate with the hydrophobic layer of the Micro-LED chips facing toward the target substrate and the Micro-LED chips facing away from the target substrate;

and irradiating laser from one side of the transfer head far away from the target substrate, and peeling between the transfer head and the hydrophilic layer so as to peel the plurality of the Micro-LED chips which are grabbed off the transfer head and fix the Micro-LED chips on the target substrate.

10. The transfer method according to any one of claims 1 to 9, wherein the target substrate comprises an adhesive layer and a driving back plate arranged in a stack, the adhesive layer being used for fixing the plurality of Micro-LED chips to the target substrate.

11. The transfer method according to any one of claims 1 to 10, wherein after said fixing the grasped plurality of Micro-LED chips onto a target substrate, the method further comprises:

and heating the target substrate, and removing the hydrophobic layer of the Micro-LED chip.

12. The transfer method according to any of claims 1 to 11, further comprising a first electrode layer on said Micro-LED chip, said first electrode layer being disposed between said Micro-LED chip and said hydrophobic layer.

13. The transfer method according to claim 12, wherein after said fixing the grasped plurality of Micro-LED chips to a target substrate, the method further comprises:

and preparing a second electrode layer on one side of the Micro-LED chip far away from the target substrate.

14. The transfer method according to any one of claims 1 to 13, wherein the transfer head further comprises:

a glass substrate;

a transparent layer disposed on the glass substrate;

the high polymer material array layer is arranged on one side, away from the glass substrate, of the transparent layer and comprises a plurality of high polymer material layers, and the grooves are formed between the adjacent high polymer material layers;

and under the condition that the side of the transfer head far away from the Micro-LED chips is irradiated by laser, peeling between the transparent layer and the hydrophilic layer so that the grabbed Micro-LED chips are peeled off the transfer head and are fixed to the target substrate.

15. The transfer method according to any one of claims 1 to 14, wherein a material of the hydrophobic layer is a self-assembled thin film SAM.

16. A wafer is characterized by comprising Micro light-emitting diode (LED) Micro-LED chips, wherein a hydrophobic layer is arranged on one side of each Micro-LED chip far away from the wafer.

17. The wafer of claim 16, wherein the Micro-LED chips and the wafer are peeled apart when the wafer is irradiated with laser light on a side thereof remote from the Micro-LED chips.

18. The wafer of claim 16 or 17, wherein the Micro-LED chip further comprises a first electrode layer disposed between the Micro-LED chip and the hydrophobic layer.

19. The wafer of any of claims 16 to 18, wherein a material of the hydrophobic layer is a self-assembled thin film (SAM).

20. A transfer head for grasping a Micro light emitting diode Micro-LED chip having a hydrophobic layer thereon, the transfer head comprising:

the groove is used for accommodating the Micro-LED chip, and a hydrophilic layer is arranged at the bottom of the groove, so that the hydrophobic layer of the grabbed Micro-LED chip is far away from the bottom of the groove.

21. The transfer head of claim 20, further comprising:

a glass substrate;

a transparent layer disposed on the glass substrate;

the high polymer material array layer is arranged on one side, away from the glass substrate, of the transparent layer and comprises a plurality of high polymer material layers, and the grooves are formed between the adjacent high polymer material layers.

22. The transfer head of claim 21, wherein the transparent layer and the hydrophilic layer are peeled off to allow the captured plurality of Micro-LED chips to peel off the transfer head when the transfer head is irradiated with laser light on a side thereof remote from the recess.