CN118867086B - A Micro-LED bonding and full-colorization method and system - Google Patents

Abstract

The invention relates to a Micro-LED bonding and full-color method and a system, wherein the bonding method comprises the following steps: alternately depositing paramagnetic metal films and ferromagnetic metal films on the electrodes of the Micro-LED chip; depositing a single-layer ferromagnetic metal film on an electrode of the TFT substrate; setting a metal bump array on the surface of the TFT substrate corresponding to the pixel points; magnetizing the Micro-LED chip and the TFT substrate which are deposited with the metal film; placing the magnetized Micro-LED chip and the TFT substrate into deionized water for fluid magnetic dynamic self-assembly; and placing the Micro-LED chip and the TFT substrate which are subjected to fluid magnetic dynamic self-assembly into chemical plating solution, so that metal bumps on the Micro-LED chip and the TFT substrate are self-grown and interconnected until ohmic contact is realized. The Micro-LED chips are prevented from being mutually adsorbed in the fluid magnetic dynamic self-assembly process, and selective self-bonding of the chips is realized through patterning photoresist and metal bumps.

Description

A Micro-LED bonding and full-colorization method and system

Technical Field

The present invention relates to a Micro-LED bonding and full-colorization method and system, and belongs to the technical field of high-density electronic packaging interconnection process.

Background Art

Display technology is an important part of human-computer interaction and information display. With the advancement of science and technology and the continuous growth of demand, display technology is also constantly developing and evolving. At present, the main display technologies include liquid crystal display technology (LCD), organic light-emitting diode display technology (OLED), Micro-LED display technology, quantum dot display technology, etc. Micro-LED display technology is an emerging display technology that uses micron-level LED chips and has the advantages of high brightness, high contrast, and fast response. Compared with other display technologies, Micro-LED has a higher pixel density and a wider color range.

Although Micro-LED display technology has significant advantages, it is still immature and still faces some technical bottlenecks in chips, backplanes, mass transfer, full colorization, bonding, driving, and detection and repair. Mass transfer, full colorization, and bonding are the core technologies of Micro-LED, which have a significant impact on product quality, efficiency, and cost.

When realizing a display array that combines Micro-LED with circuit drivers, it is necessary to transfer Micro-LED chips in large quantities multiple times. The amount of chips transferred each time is huge, so high requirements are placed on the stability and accuracy of the transfer process. Especially when realizing RGB full-color display, it is necessary to transfer R/G/B chips separately, which increases the complexity and difficulty of the transfer process. Therefore, for the transfer process of the display array that combines Micro-LED with circuit drivers, the positioning and accuracy of the chips are crucial.

The current mainstream mass transfer methods include electrostatic force stamping, elastic stamping, laser-assisted transfer, fluid self-assembly, roller transfer and other methods.

Electrostatic force adsorption transfer is based on the principle of mutual attraction between dissimilar charges, and the LED chip is captured and released by applying opposite charges. This transfer process is a selective array chip transfer technology with the advantage of high efficiency. However, the electrostatic transfer process also has some key technical difficulties. First, the flatness of the LED chip substrate is required to be high; second, multi-dimensional high-precision alignment is required; and finally, the voltage of the electrode transfer head needs to be precisely controlled.

X-Celeprint uses a polydimethylsiloxane (PDMS) elastomer stamp as a carrier, relying on van der Waals forces to transfer the Micro-LED array from the native substrate to the target backplane during the transfer process. And after thousands of transfer cycles, the elastomer remains stable without noticeable changes.

Laser-assisted transfer technology has higher difficulty and more stringent process requirements, but its high transfer yield and fast speed have attracted a large number of researchers from industry and academia. Therefore, this technology is considered to be the transfer technology with the greatest commercial potential.

Fluid self-assembly technology uses the drag force of the fluid to transfer the Micro-LED to the backplane. This technology was proposed by eLux, in which the contact points on the substrate are designed to be well-shaped, and the Micro-LED will fall into these wells as the deionized water flows, thereby achieving self-assembly.

The roller transfer technology was proposed by the Korea Institute of Machinery and Materials in 2017. The process is to use a soft roller stamp to transfer Micro-LED and TFT from the wafer three times to build a Micro-LED array on a flexible substrate. The alignment accuracy of this method is within 3 μm and the yield is close to 99.9%.

The various mass transfer methods listed above all have the following disadvantages: (1) Transfer accuracy and speed: Mass transfer technology requires micron-level chip transfer, and requires high speed and high accuracy. The current transfer speed is slow, and chips are prone to damage or position shift during the transfer process, resulting in low production efficiency.

(2) Transfer cost: The current mass transfer technology requires high equipment and process costs, including transfer equipment, various transfer adhesives, calibration systems, etc. These costs make the production cost of Micro-LED high, limiting its large-scale commercial application.

(3) Reliability and consistency: During the mass transfer process, it is necessary to ensure that the Micro-LED chips are accurately positioned, have consistent quality, and have good adhesion to the substrate. However, current technology has not been able to completely solve problems such as chip damage, missing transfer, and dimensional deformation that may occur during the transfer process, resulting in instability in the production process and volatility in product quality.

(4) Large-scale production: The current mass transfer technology is still mainly in the laboratory stage and has not yet achieved large-scale production. To realize the commercial application of Micro-LED technology, it is necessary to solve the problems of large-scale production and industrial application of the transfer process.

The Chinese invention patent with the publication number "CN116544318A" discloses a magnetic force-assisted self-alignment method for the bonding process of Micro-LED chips. The method deposits Fe3O4 magnetic nanoparticles on the electrodes of the Micro-LED chips so that the electrodes of the Micro-LED chips can be magnetized. A high-density bonding bump array with Fe3O4 magnetic nanoparticles is prepared on the substrate. Under the action of the magnetic field, the high-density bonding bumps generate magnetism. During the bonding process of the Micro-LED chip and the bonding bumps, due to the mutual attraction of the magnetic field force, high-precision self-alignment of the Micro-LED electrodes and the bonding bumps is achieved, and high-reliability Micro-LED chip bonding is further achieved.

However, the problem with the above patent is that the Micro-LED chip with ferromagnetic metal electrodes will cause mutual adsorption during the self-assembly process and cannot achieve fluid magnetic dynamic self-assembly.

Summary of the invention

In order to solve the problems existing in the above-mentioned prior art, the present invention proposes a Micro-LED bonding and full-colorization method and system; avoid the mutual adsorption of Micro-LED chips during the process of fluid magnetic dynamic self-assembly, and realize the selective self-adsorption of Micro-LED chips through patterned photoresist.

The technical solution of the present invention is as follows:

In one aspect, the present invention provides a Micro-LED bonding method, comprising the following steps:

Alternately depositing paramagnetic metal films and ferromagnetic metal films on the electrodes of the Micro-LED chip; depositing a single layer of ferromagnetic metal film on the electrodes of the TFT substrate; and setting a metal bump array corresponding to the pixel points on the surface of the TFT substrate;

Magnetizing the Micro-LED chip and TFT substrate on which the metal film has been deposited;

The magnetized Micro-LED chip and TFT substrate were placed in deionized water for fluid magnetic dynamic self-assembly;

The Micro-LED chip and TFT substrate that have completed fluid magnetic dynamic self-assembly are placed in a chemical plating solution, allowing the metal bumps on the Micro-LED chip and the TFT substrate to self-grow and interconnect until ohmic contact is achieved.

As a preferred embodiment, before the fluid magnetic dynamic self-assembly step, the method further comprises the following steps:

The photoresist is spin-coated on the designated area of the surface of the TFT substrate after the magnetization treatment and then subjected to photolithography treatment to form a patterned photoresist on the designated area of the surface of the TFT substrate.

As a preferred embodiment, in the step of placing the magnetized Micro-LED chip and the TFT substrate into deionized water:

A non-ionic surfactant is added to the deionized water for wettability preparation, and the concentration of the non-ionic surfactant is 0.001%-0.03%.

As a preferred embodiment, in the step of alternately depositing a paramagnetic metal film and a ferromagnetic metal film on the electrodes of the Micro-LED chip, the material of the paramagnetic metal film is copper, palladium, platinum or aluminum.

As a preferred embodiment, in the step of alternately depositing a paramagnetic metal film and a ferromagnetic metal film on the electrodes of the Micro-LED chip, the material of the ferromagnetic metal film is nickel, cobalt or iron.

As a preferred embodiment, in the steps of alternately depositing paramagnetic metal films and ferromagnetic metal films on the electrodes of the Micro-LED chip, and depositing a single layer of ferromagnetic metal film on the electrodes of the TFT substrate, the deposition method is vacuum evaporation, vacuum magnetron sputtering, electroplating or chemical plating.

As a preferred embodiment, in the step of self-growing and interconnecting the metal bumps on the Micro-LED chip and the TFT substrate, the environment is controlled to be in a constant temperature environment.

On the other hand, the present invention further provides a Micro-LED bonding system, comprising:

A deposition module is used to alternately deposit paramagnetic metal films and ferromagnetic metal films on the electrodes of the Micro-LED chip; deposit a single layer of ferromagnetic metal film on the electrodes of the TFT substrate; and set a metal bump array corresponding to the pixel points on the surface of the TFT substrate;

The magnetization module is used to magnetize the Micro-LED chip and TFT substrate on which the metal film is deposited;

The transfer bonding module is used to place the magnetized Micro-LED chip and TFT substrate into deionized water for fluid magnetic dynamic self-assembly; and to place the Micro-LED chip and TFT substrate that have completed fluid magnetic dynamic self-assembly into a chemical plating solution to allow the metal bumps on the Micro-LED chip and TFT substrate to self-grow and interconnect until ohmic contact is achieved.

On the other hand, the present invention also provides a Micro-LED full-color method, comprising the following steps:

Paramagnetic metal films and ferromagnetic metal films are alternately deposited on the electrodes of the three-color Micro-LED chips; a single layer of ferromagnetic metal film is deposited on the electrodes of the TFT substrate; and a metal bump array is arranged on the surface of the TFT substrate corresponding to the pixel points;

Magnetizing the Micro-LED chip and TFT substrate on which the metal film has been deposited;

Select one color of the magnetized Micro-LED chip to perform the bonding step, which specifically includes:

Place the magnetized Micro-LED chips of corresponding colors into deionized water;

Spin-coating a photoresist on a designated area of the surface of the TFT substrate after the magnetization treatment and performing a photolithography treatment, so as to form a patterned photoresist on the designated area of the surface of the TFT substrate to reveal a pixel area corresponding to the selected color;

The TFT substrate with the patterned photoresist is placed in deionized water to perform fluid magnetic dynamic self-assembly;

The Micro-LED chip of the corresponding selected color and the TFT substrate that have completed the fluid magnetic dynamic self-assembly are placed in a chemical plating solution, so that the metal bumps between the Micro-LED chip of the corresponding selected color and the TFT substrate are self-grown and interconnected until ohmic contact is achieved and bonding is completed;

The bonded TFT substrate is de-photoresisted and cleaned with deionized water, and the other two colors of Micro-LED chips are selected to repeat the above bonding steps to complete the bonding of the other two colors of Micro-LED chips and the TFT substrate to achieve full color.

On the other hand, the present invention further provides a Micro-LED full-color system, comprising:

The deposition module alternately deposits paramagnetic metal films and ferromagnetic metal films on the electrodes of the three colors of Micro-LED chips; deposits a single layer of ferromagnetic metal film on the electrodes of the TFT substrate; and sets a metal bump array corresponding to the pixel points on the surface of the TFT substrate;

The magnetization module magnetizes the Micro-LED chip and TFT substrate on which the metal film is deposited;

The transfer bonding module is used to place the magnetized Micro-LED chip of the corresponding color into deionized water; spin-coat the designated area of the surface of the magnetized TFT substrate with photoresist and perform photolithography, and form a patterned photoresist on the designated area of the surface of the TFT substrate to reveal the pixel area corresponding to the selected color; place the TFT substrate with the patterned photoresist into deionized water and perform fluid magnetic dynamic self-assembly; place the Micro-LED chip of the corresponding selected color and the TFT substrate that have completed the fluid magnetic dynamic self-assembly into a chemical plating solution, so that the metal bumps between the Micro-LED chip of the corresponding selected color and the TFT substrate are self-grown and interconnected, until ohmic contact is achieved, and bonding is completed;

The full-colorization module is used to remove the photoresist and clean the bonded TFT substrate with deionized water, select the other two colors of Micro-LED chips and repeatedly place them into the above transfer bonding module to complete the bonding of the other two colors of Micro-LED chips with the TFT substrate to achieve full colorization.

The present invention has the following beneficial effects:

The present invention provides a Micro-LED bonding and full-colorization method and system. By alternately depositing paramagnetic and ferromagnetic metal films on Micro-LED electrodes, the magnetized Micro-LED electrodes are paramagnetic, which prevents the Micro-LED chips from adsorbing each other during the dynamic self-assembly of fluid magnetic materials. At the same time, the spin-coated photoresist is cleverly matched with the metal bumps on the substrate to achieve the selective self-assembly process of the Micro-LED chips, while effectively protecting the already bonded chips. Compared with the existing mass transfer and bonding processes, the method provided by the present invention is simpler, reduces the dependence on large and costly equipment, and significantly improves the efficiency and yield of transfer and bonding.

The present invention provides a Micro-LED bonding and full-colorization method and system, which performs wettability preparation on deionized water and adds a non-ionic surfactant to enable the Micro-LED chip to be better dispersed in the flowing deionized water.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a method flow chart of Embodiment 1 of the present invention;

FIG2 is a schematic diagram of the structure of a Micro-LED chip in an embodiment of the present invention;

FIG3 is a schematic diagram of magnetizing a Micro-LED chip according to an embodiment of the present invention;

FIG4 is a schematic diagram of magnetizing a TFT substrate in an embodiment of the present invention;

FIG5 is a schematic diagram of the adsorption process of a Micro-LED chip using a single ferromagnetic layer on an electrode in the prior art;

FIG6 is a schematic diagram of a method flow chart of Embodiment 3 of the present invention;

FIG. 7 is a schematic diagram of the process of performing full colorization in the third embodiment of the present invention.

The accompanying drawings in the figure are marked as follows:

1. Sapphire substrate; 2. Buffer layer; 3. n-GaN substrate; 4. Quantum well layer; 5. p-GaN substrate; 6. ITO conductive film; 7. SiO2 film; 8. Au electrode; 9. Paramagnetic layer; 10. Ferromagnetic layer; 11. N electrode of Micro-LED chip; 12. P electrode of Micro-LED chip; 13. Anode of TFT substrate; 14. Metal bump array; 15. Cathode of TFT substrate.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and/or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or combinations thereof.

The term "and/or" means and includes any and all possible combinations of one or more of the associated listed items.

Embodiment 1:

Referring to FIG. 1 , this embodiment provides a Micro-LED bonding method, comprising the following steps:

S100, alternately depositing paramagnetic metal films and ferromagnetic metal films on electrodes of the Micro-LED chip.

The paramagnetic material used in the paramagnetic metal film may be copper (Cu), palladium (Pd), platinum (Pt) or aluminum (Al); the ferromagnetic material used in the ferromagnetic metal film may be nickel (Ni), cobalt (Co) or iron (Fe). The metal deposition method includes but is not limited to vacuum evaporation, vacuum magnetron sputtering, electroplating, and chemical plating; the deposition thickness is controlled at 50-5000nm.

S200, depositing a single layer of ferromagnetic metal film on the electrode of the TFT substrate; and arranging a metal bump array corresponding to pixel points on the surface of the TFT substrate.

The ferromagnetic material used in the single-layer ferromagnetic metal film may be nickel (Ni), cobalt (Co) or iron (Fe). The metal deposition method includes but is not limited to vacuum evaporation, vacuum magnetron sputtering, electroplating, and chemical plating; the deposition thickness is controlled to be 50-5000nm.

S300, magnetizing the Micro-LED chip and TFT substrate on which the metal film is deposited; after the magnetization is completed, the electrodes of the Micro-LED chip on which the paramagnetic metal film and the ferromagnetic metal film are alternately deposited will be paramagnetic, thereby preventing the Micro-LED chips from adsorbing each other during the process of fluid magnetic dynamic self-assembly; and the electrodes of the TFT substrate will be ferromagnetic.

S400: Place the magnetized Micro-LED chip and TFT substrate into flowing deionized water to perform fluid magnetic dynamic self-assembly, so as to achieve accurate positioning and fixation of the Micro-LED chip in a specific area of the TFT substrate through fluid magnetic dynamic self-assembly technology.

In this embodiment, the flowing deionized water is prepared by adding a non-ionic surfactant for wettability, and the concentration of the non-ionic surfactant is 0.001%-0.03%. The deionized water prepared for wettability can make the Micro-LED chips more dispersed in the flowing deionized water.

S500, placing the Micro-LED chip and TFT substrate that have completed fluid magnetic dynamic self-assembly into a chemical plating solution, so that the metal bumps on the Micro-LED chip and the TFT substrate are self-grown and interconnected until ohmic contact is achieved.

As a preferred implementation of this embodiment, before step S300, the following steps are further included:

The photoresist is spin-coated on the designated area of the surface of the TFT substrate after the magnetization treatment and then subjected to photolithography treatment to form a patterned photoresist on the designated area of the surface of the TFT substrate. Only the predetermined pixel area is exposed for subsequent fluid magnetic dynamic self-assembly, while protecting the Micro-LED chips on the pixel areas that have been bonded.

As a preferred implementation, in step S400, the environment is controlled to be at a constant temperature to promote the self-growth and interconnection of the metal bumps on the Micro-LED chip and the TFT substrate, and achieve good ohmic contact through physical and chemical effects to ensure efficient and stable operation of the electronic device.

FIG2 is a schematic diagram of the structure of the Micro-LED chip in this embodiment. As shown in FIG2, the Micro-LED chip is provided with a sapphire substrate 1, a buffer layer 2, an n-GaN substrate 3, a quantum well layer 4, a p-GaN substrate 5, an ITO conductive film 6 and a SiO2 film 7 on the surface in order from bottom to top. A sunken Au electrode 8 is formed on one side of the surface of the SiO2 film 7, and a P electrode 12 of the Micro-LED chip is formed above the Au electrode 8. An N electrode 11 of the Micro-LED chip is formed on the other side of the SiO2 film 7 relative to the P electrode of the Micro-LED chip. Paramagnetic layers 9 and ferromagnetic layers 10 are alternately deposited on the N electrode 11 of the Micro-LED chip and the P electrode 12 of the Micro-LED chip. In this embodiment, the deposition method is sputtering, and the materials of the paramagnetic layer 9 and the ferromagnetic layer 10 are selected from copper and nickel, respectively, with a thickness of 100 nm.

FIG3 is a schematic diagram of magnetizing a Micro-LED chip. As shown in FIG3 , after the electrodes of the Micro-LED chip are magnetized by an external uniform magnetic field, the electrodes of the Micro-LED chip become paramagnetic.

FIG4 is a schematic diagram of magnetizing a TFT substrate. As shown in FIG4 , the anode 13 and the cathode 15 of the TFT substrate are magnetized by an external uniform magnetic field, and the metal bump array 14 disposed on the surface of the TFT substrate becomes ferromagnetic.

FIG5 is an example diagram of the prior art using a single ferromagnetic layer on the electrode of a Micro-LED chip. As shown in FIG5 , the Micro-LED chips having a single ferromagnetic layer electrode will adsorb each other during the fluid dynamic self-assembly process, resulting in self-assembly failure.

Embodiment 2:

This embodiment provides a Micro-LED bonding system, including:

A deposition module, used to alternately deposit a paramagnetic metal film and a ferromagnetic metal film on the electrodes of the Micro-LED chip; deposit a single layer of ferromagnetic metal film on the electrodes of the TFT substrate; and set a metal bump array corresponding to the pixel points on the surface of the TFT substrate; this module is used to implement the functions of steps S100 and S200 in the first embodiment, which will not be repeated here;

A magnetization module, used to magnetize the Micro-LED chip and the TFT substrate on which the metal film is deposited; this module is used to implement the function of step S300 in the first embodiment, and will not be described in detail here;

The transfer bonding module is used to place the magnetized Micro-LED chip and TFT substrate into deionized water for fluid magnetic dynamic self-assembly; and place the Micro-LED chip and TFT substrate that have completed fluid magnetic dynamic self-assembly into a chemical plating solution to allow the metal bumps on the Micro-LED chip and the TFT substrate to self-grow and interconnect until ohmic contact is achieved; this module is used to implement the functions of steps S400 and S500 in Example 1, which will not be repeated here.

Embodiment three:

6 , this embodiment proposes a Micro-LED full-color method, which specifically includes the following steps:

A100, alternately depositing paramagnetic metal films and ferromagnetic metal films on the electrodes of the three colors of Micro-LED chips; depositing a single layer of ferromagnetic metal film on the electrodes of the TFT substrate; and setting a metal bump array on the surface of the TFT substrate corresponding to the pixel points;

A200, magnetize the Micro-LED chip and TFT substrate with deposited metal film;

A300, selecting one color of the magnetized Micro-LED chip to perform bonding steps, specifically including:

A301, placing the magnetized Micro-LED chips of corresponding colors into deionized water;

A302, spin-coating a photoresist on a designated area of the surface of the TFT substrate after the magnetization treatment and performing a photolithography treatment, so as to form a patterned photoresist on the designated area of the surface of the TFT substrate to reveal a pixel area corresponding to the selected color;

A303, placing the TFT substrate with the patterned photoresist in deionized water to perform fluid magnetic dynamic self-assembly;

A304, placing the Micro-LED chip of the corresponding selected color and the TFT substrate that have completed fluid magnetic dynamic self-assembly into a chemical plating solution, so that the metal bumps between the Micro-LED chip of the corresponding selected color and the TFT substrate are self-grown and interconnected until ohmic contact is achieved and bonding is completed;

A400, remove the photoresist and clean the TFT substrate after bonding, and confirm whether all colors of Micro-LED chips have completed bonding. If so, proceed to step A401, otherwise continue to select the next color Micro-LED chip and repeat the above steps A300~A304.

A401, end the process and complete full colorization.

To facilitate those skilled in the art to more clearly understand the full-colorization method of this embodiment, a more specific process description is provided below:

Specifically referring to FIG. 7 , in this embodiment, firstly, a magnetic metal film is alternately deposited on the three colors of Micro-LED chips, and a single layer of ferromagnetic metal film is deposited on the electrodes of the TFT substrate, and a metal bump array is arranged on the surface of the TFT substrate corresponding to the pixel points. Then, the electrodes of the Micro-LED chip and the TFT substrate are magnetized.

Select the Micro-LED chip that has been magnetized with blue light and put it into deionized water.

Then, the TFT substrate is subjected to a first spin coating of photoresist and a photolithography process to form a patterned photoresist covering the area except the blue light pixel area on the TFT substrate.

The TFT substrate after photolithography is placed in deionized water for fluid magnetic self-assembly to obtain a combination of a blue light Micro-LED chip and a TFT substrate.

Place the assembly into a chemical plating solution and control the temperature environment to complete the bonding of the blue light Micro-LED chip and the TFT substrate.

The TFT substrate that has completed the first bonding is subjected to a photoresist removal treatment and then a deionized water cleaning treatment.

The Micro-LED chip after magnetization treatment of red light was selected and placed in deionized water.

The TFT substrate is then subjected to a second spin coating of photoresist and photolithography processing to form a patterned photoresist covering the TFT substrate except for the red light pixel area. At this stage, the blue light Micro-LED chip that has been bonded in the blue light pixel area will be protected by the photoresist.

The TFT substrate after photolithography is then placed in deionized water for fluid magnetic self-assembly to obtain a combination of red light, blue light Micro-LED chips and TFT substrates.

Place the assembly into a chemical plating solution and control the temperature environment to complete the bonding of the red light Micro-LED chip and the TFT substrate.

The TFT substrate that has completed the second bonding is subjected to a photoresist removal treatment and then to a deionized water cleaning treatment.

Finally, the Micro-LED chip after green light magnetization treatment is placed in deionized water.

The TFT substrate is subjected to a third spin coating of photoresist and photolithography processing to form a patterned photoresist covering the TFT substrate except the green pixel area. At this stage, the blue and red Micro-LED chips that have been bonded in the blue pixel area and the red pixel area will be protected by the photoresist.

The TFT substrate after photolithography is then placed in deionized water for fluid magnetic self-assembly to obtain a combination of red, blue, and green light Micro-LED chips and TFT substrates.

Place the assembly into a chemical plating solution and control the temperature environment to complete the bonding of the green light Micro-LED chip and the TFT substrate.

The TFT substrate that has completed the third bonding is subjected to a photoresist removal treatment, followed by a deionized water cleaning treatment to complete full colorization.

Embodiment 4:

This embodiment proposes a Micro-LED full-color system, including:

A deposition module, alternately depositing paramagnetic metal films and ferromagnetic metal films on the electrodes of the three colors of Micro-LED chips; depositing a single layer of ferromagnetic metal film on the electrodes of the TFT substrate; and setting a metal bump array corresponding to the pixel points on the surface of the TFT substrate; this module is used to implement the function of step A100 in embodiment 1, and will not be repeated here;

A magnetization module is used to magnetize the Micro-LED chip and the TFT substrate on which the metal film is deposited. This module is used to implement the function of step A200 in the first embodiment, and will not be described in detail here.

A transfer bonding module is used to place the magnetized Micro-LED chip of the corresponding color into deionized water; spin-coat the designated area of the surface of the TFT substrate after the magnetization treatment with photoresist and perform photolithography, and form a patterned photoresist in the designated area of the surface of the TFT substrate to reveal the pixel area corresponding to the selected color; place the TFT substrate with the patterned photoresist into deionized water and perform fluid magnetic dynamic self-assembly; place the Micro-LED chip of the corresponding selected color and the TFT substrate that have completed the fluid magnetic dynamic self-assembly into a chemical plating solution, so that the metal bumps between the Micro-LED chip of the corresponding selected color and the TFT substrate are self-grown and interconnected until ohmic contact is achieved and bonding is completed; this module is used to implement the functions of steps A300 to A304 in Example 1, which will not be repeated here;

The full-colorization module is used to remove the photoresist and clean the bonded TFT substrate with deionized water, select the Micro-LED chips of the other two colors and repeatedly place them into the transfer bonding module to complete the bonding of the Micro-LED chips of the other two colors with the TFT substrate to achieve full colorization; this module is used to implement the functions of steps A400~A401 in Example 1, which will not be repeated here.

In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And/or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and/or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character "/" generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

Those of ordinary skill in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented in a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

In several embodiments provided in the present application, if any function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory; hereinafter referred to as: ROM), random access memory (Random Access Memory; hereinafter referred to as: RAM), disk or optical disk, and other media that can store program codes.

The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims (9)

1. A Micro-LED bonding method, comprising the following steps: Alternately depositing paramagnetic metal films and ferromagnetic metal films on the electrodes of the Micro-LED chip; depositing a single layer of ferromagnetic metal film on the electrodes of the TFT substrate; and setting a metal bump array corresponding to the pixel points on the surface of the TFT substrate; Magnetizing the Micro-LED chip and TFT substrate on which the metal film has been deposited; Spin-coating a photoresist on a designated area of the surface of the TFT substrate after the magnetization treatment and performing a photolithography treatment to form a patterned photoresist on the designated area of the surface of the TFT substrate, exposing a predetermined pixel area for subsequent fluid magnetic dynamic self-assembly; The magnetized Micro-LED chip and TFT substrate were placed in deionized water for fluid magnetic dynamic self-assembly; The Micro-LED chip and TFT substrate that have completed fluid magnetic dynamic self-assembly are placed in a chemical plating solution, allowing the metal bumps on the Micro-LED chip and the TFT substrate to self-grow and interconnect until ohmic contact is achieved. 2. A Micro-LED bonding method according to claim 1, characterized in that in the step of placing the magnetized Micro-LED chip and the TFT substrate into deionized water: A non-ionic surfactant is added to the deionized water for wettability preparation, and the concentration of the non-ionic surfactant is 0.001%-0.03%. 3. A Micro-LED bonding method according to claim 1, characterized in that: In the step of alternately depositing a paramagnetic metal film and a ferromagnetic metal film on the electrodes of the Micro-LED chip, the material of the paramagnetic metal film is copper, palladium, platinum or aluminum. 4. A Micro-LED bonding method according to claim 1, characterized in that: In the step of alternately depositing a paramagnetic metal film and a ferromagnetic metal film on the electrodes of the Micro-LED chip, the material of the ferromagnetic metal film is nickel, cobalt or iron. 5. The Micro-LED bonding method according to claim 1, characterized in that: In the steps of alternately depositing paramagnetic metal films and ferromagnetic metal films on the electrodes of the Micro-LED chip, and depositing a single layer of ferromagnetic metal film on the electrodes of the TFT substrate, the deposition method is vacuum evaporation, vacuum magnetron sputtering, electroplating or chemical plating. 6. A Micro-LED bonding method according to claim 1, characterized in that: In the step of self-growing and interconnecting the metal bumps on the Micro-LED chip and the TFT substrate, the environment is controlled at a constant temperature. 7. A Micro-LED bonding system, comprising: A deposition module is used to alternately deposit paramagnetic metal films and ferromagnetic metal films on the electrodes of the Micro-LED chip; deposit a single layer of ferromagnetic metal film on the electrodes of the TFT substrate; and set a metal bump array corresponding to the pixel points on the surface of the TFT substrate; The magnetization module is used to magnetize the Micro-LED chip and TFT substrate on which the metal film is deposited; and to spin-coat the photoresist on the designated area of the surface of the TFT substrate after the magnetization treatment and perform photolithography treatment to form a patterned photoresist on the designated area of the surface of the TFT substrate, revealing a predetermined pixel area for subsequent fluid magnetic dynamic self-assembly; The transfer bonding module is used to place the magnetized Micro-LED chip and TFT substrate into deionized water for fluid magnetic dynamic self-assembly; and to place the Micro-LED chip and TFT substrate that have completed fluid magnetic dynamic self-assembly into a chemical plating solution to allow the metal bumps on the Micro-LED chip and TFT substrate to self-grow and interconnect until ohmic contact is achieved. 8. A method for full-colorization of Micro-LED, characterized by comprising the following steps: Paramagnetic metal films and ferromagnetic metal films are alternately deposited on the electrodes of the three-color Micro-LED chips; a single layer of ferromagnetic metal film is deposited on the electrodes of the TFT substrate; and a metal bump array is arranged on the surface of the TFT substrate corresponding to the pixel points; Magnetizing the Micro-LED chip and TFT substrate on which the metal film has been deposited; Select one color of the magnetized Micro-LED chip to perform the bonding step, which specifically includes: Place the magnetized Micro-LED chips of corresponding colors into deionized water; Spin-coating a photoresist on a designated area of the surface of the TFT substrate after the magnetization treatment and performing a photolithography treatment, so as to form a patterned photoresist on the designated area of the surface of the TFT substrate to reveal a pixel area corresponding to the selected color; The TFT substrate with the patterned photoresist is placed in deionized water to perform fluid magnetic dynamic self-assembly; The Micro-LED chip of the corresponding selected color and the TFT substrate that have completed the fluid magnetic dynamic self-assembly are placed in a chemical plating solution, so that the metal bumps between the Micro-LED chip of the corresponding selected color and the TFT substrate are self-grown and interconnected until ohmic contact is achieved and bonding is completed; The bonded TFT substrate is de-photoresisted and cleaned with deionized water, and the other two colors of Micro-LED chips are selected to repeat the above bonding steps to complete the bonding of the other two colors of Micro-LED chips and the TFT substrate to achieve full color. 9. A Micro-LED full-color system, comprising: The deposition module alternately deposits paramagnetic metal films and ferromagnetic metal films on the electrodes of the three colors of Micro-LED chips; deposits a single layer of ferromagnetic metal film on the electrodes of the TFT substrate; and sets a metal bump array corresponding to the pixel points on the surface of the TFT substrate; The magnetization module magnetizes the Micro-LED chip and TFT substrate on which the metal film is deposited; The transfer bonding module is used to place the magnetized Micro-LED chip of the corresponding color into deionized water; spin-coat the designated area of the surface of the magnetized TFT substrate with photoresist and perform photolithography, and form a patterned photoresist on the designated area of the surface of the TFT substrate to reveal the pixel area corresponding to the selected color; place the TFT substrate with the patterned photoresist into deionized water and perform fluid magnetic dynamic self-assembly; place the Micro-LED chip of the corresponding selected color and the TFT substrate that have completed the fluid magnetic dynamic self-assembly into a chemical plating solution, so that the metal bumps between the Micro-LED chip of the corresponding selected color and the TFT substrate are self-grown and interconnected, until ohmic contact is achieved, and bonding is completed; The full-colorization module is used to remove the photoresist and clean the bonded TFT substrate with deionized water, select the other two colors of Micro-LED chips and repeatedly place them into the above transfer bonding module to complete the bonding of the other two colors of Micro-LED chips with the TFT substrate to achieve full colorization.