Mini / Micro LED and manufacturing method thereof

Abstract

The present invention relates to the technical field of LED display, and discloses a Mini / Micro LED and a manufacturing method thereof. The manufacturing method comprises: preparing metal conductive particle balls by a mechanical separation process or a spraying process; coating a layer of insulating coating on the surface of the metal conductive particle balls and air-drying to form an insulating film; placing the metal conductive particle balls coated with the insulating film into a provided insulating glue and stirring to form an anisotropic conductive glue; printing the anisotropic conductive glue onto a solder pad of a provided substrate through a provided hydrophobic nano-steel mesh; peeling off the hydrophobic nano-steel mesh; attaching the provided Mini / Micro LED chip to the anisotropic conductive glue located on the solder pad, and applying heat and pressure to longitudinally rupture the insulating film to expose the metal conductive particle balls wrapped in the insulating film, wherein the metal conductive particle balls respectively contact the Mini / Micro LED chip and the solder pad to form a vertical conductive path, and the insulating glue is initially cured to obtain the Mini / Micro LED, thereby achieving stable welding quality, low maintenance difficulty, and low maintenance cost.

Description

Technical Field

[0001] The present invention relates to the technical field of LED displays, and in particular to a Mini / Micro LED and a manufacturing method thereof. Background Art

[0002] Although the reflow process is widely used in electronics manufacturing, it also has some temperature-related disadvantages. The following are the disadvantages of the reflow process when applied to Mini / Micro LED display soldering:

[0003] 1) During the reflow soldering process, the soldering temperature is usually high. High-temperature soldering can easily damage the chip, resulting in unstable soldering quality.

[0004] 2) Furthermore, when a chip fails, the PCB or glass substrate must be heated to a high temperature to melt the solder paste and remove the chip. However, due to the physical phenomena of heat diffusion and heat conduction, the high temperature is quickly transferred to surrounding chips, making it difficult to precisely target the damaged chip with the heating area. This can damage nearby healthy chips and increase the risk during the repair process.

[0005] 3) Because ACF is a single sheet of conductive film, repairing a single chip with a poor connection or malfunction is extremely difficult. Because the film already has thousands of chips connected to it, repairs often require replacing the entire sheet, rendering all chips on the ACF useless and resulting in high repair costs. Summary of the Invention

[0006] The main purpose of the present invention is to provide a Mini / Micro LED and a manufacturing method thereof, aiming to solve the technical problems of unstable welding quality, difficult maintenance and high maintenance cost of existing Mini / Micro LED chips.

[0007] To achieve the above objectives, the present invention provides a method for manufacturing Mini / Micro LEDs, the manufacturing method comprising: preparing metal conductive particle balls by a mechanical separation process or a spraying process, wherein the diameter of the metal conductive particle balls is 10 μm-20 μm;

[0008] Applying an insulating coating on the surface of the metal conductive particle ball through a coating process and air-drying the coating to form an insulating film, wherein the thickness of the insulating film is 3%-25% of the diameter of the metal conductive particle ball;

[0009] Providing an insulating glue, placing the metal conductive particle balls coated with the insulating film into the insulating glue, and stirring to form an anisotropic conductive glue;

[0010] Providing a hydrophobic nano-steel mesh having a plurality of steel pores and a substrate having a plurality of pads, and printing the anisotropic conductive paste onto the pads through the hydrophobic nano-steel mesh;

[0011] peeling off the hydrophobic nano-steel mesh;

[0012] A Mini / Micro LED chip is provided and mounted on an anisotropic conductive adhesive located on the pad. Heat and pressure are applied to longitudinally rupture the insulating film of the anisotropic conductive adhesive to expose metal conductive particle balls wrapped in the insulating film. The metal conductive particle balls are respectively in contact with the Mini / Micro LED chip and the pad to form a vertical conductive path, and the insulating adhesive of the anisotropic conductive adhesive is initially cured to obtain a Mini / Micro LED.

[0013] Furthermore, in one embodiment, the material of the insulating film is one or more of a resin, a polymer or a thermoplastic polymer; and / or the material of the insulating glue is a modified epoxy resin.

[0014] Furthermore, in one embodiment, the material of the metal conductive particle balls is one or more of tin powder, silver powder, nickel powder, gold powder, tin alloy powder, copper powder, and aluminum powder.

[0015] Furthermore, in one embodiment, after providing the Mini / Micro LED chip, mounting the Mini / Micro LED chip on the anisotropic conductive adhesive located on the pad, applying heat and pressure to longitudinally rupture the insulating film of the anisotropic conductive adhesive to expose the metal conductive particle balls wrapped in the insulating film, so that the metal conductive particle balls respectively contact the Mini / Micro LED chip and the pad to form a vertical conductive path, and initially curing the insulating adhesive of the anisotropic conductive adhesive to obtain the Mini / Micro LED, the method further includes:

[0016] Testing the Mini / Micro LED chip;

[0017] When the Mini / Micro LED chip is defective, the Mini / Micro LED chip is heated to melt the anisotropic conductive adhesive, and the defective Mini / Micro LED chip is removed and replaced with a good Mini / Micro LED chip, wherein the heating temperature is 120°C-150°C.

[0018] Furthermore, in one embodiment, the steps of providing a Mini / Micro LED chip, attaching the Mini / Micro LED chip to an anisotropic conductive adhesive located on the pad, applying heat and pressure to longitudinally rupture the insulating film of the anisotropic conductive adhesive to expose the metal conductive particle balls wrapped in the insulating film, allowing the metal conductive particle balls to contact the Mini / Micro LED chip and the pad, respectively, to form vertical conductive paths, and allowing the insulating adhesive of the anisotropic conductive adhesive to initially cure, to obtain the Mini / Micro LED are performed in two steps, including:

[0019] Mounting the Mini / Micro LED chip onto the anisotropic conductive adhesive on the pad through a mass transfer process or a SMT process;

[0020] The Mini / Micro LED chip mounted on the anisotropic conductive adhesive on the pad is heated through a hot pressing process and pressure is applied in the longitudinal direction of the Mini / Micro LED chip, so that the insulating film of the anisotropic conductive adhesive softens and breaks in the Z-axis direction to expose the metal conductive particle balls wrapped in the insulating film. The metal conductive particle balls are compressed and contact the Mini / Micro LED chip and the pad respectively to form a vertical conductive path, and the insulating glue of the anisotropic conductive adhesive is initially cured to obtain a Mini / Micro LED.

[0021] Furthermore, in one embodiment, the step of coating a layer of insulating coating on the surface of the metal conductive particle ball by a coating process and air-drying the coating to form an insulating film includes:

[0022] The metal conductive particle balls are immersed in a chemical solution by a chemical deposition method, an insulating coating is formed on the surface of the metal conductive particle balls by a chemical reaction, and the insulating coating is air-dried to form an insulating film.

[0023] Furthermore, in one embodiment, the step of coating a layer of insulating coating on the surface of the metal conductive particle ball by a coating process and air-drying the coating to form an insulating film includes:

[0024] The insulating coating material is deposited onto the surface of the metal conductive particle ball by physical vapor deposition to form an insulating coating, and the insulating coating is air-dried to form an insulating film.

[0025] Furthermore, in one embodiment, the step of providing an insulating glue, placing the metal conductive particle balls coated with the insulating film into the insulating glue, and stirring to form an anisotropic conductive glue includes:

[0026] An insulating glue is provided, metal conductive particle balls coated with the insulating film are placed in the insulating glue, and the metal conductive particle balls are evenly distributed in the insulating glue by low-speed stirring, thereby forming an anisotropic conductive glue; or, an insulating glue is provided, metal conductive particle balls coated with the insulating film are placed in the insulating glue, and the metal conductive particle balls are evenly distributed in the insulating glue by a planetary mixer through a combined motion of rotation and revolution, thereby forming an anisotropic conductive glue.

[0027] Furthermore, in one embodiment, the step of providing a hydrophobic nano-steel mesh having a plurality of steel pores comprises:

[0028] Providing a steel plate, and drilling steel holes on the steel plate corresponding to the welding pads of the substrate to form a steel mesh;

[0029] A layer of nano-hydrophobic coating is coated on the steel mesh to obtain a hydrophobic nano-steel mesh.

[0030] The present invention also provides a Mini / Micro LED, which is manufactured by the manufacturing method.

[0031] In the technical solution provided by the present invention, metal conductive particle balls with a diameter of 10μm-20μm are prepared by a mechanical separation process or a spraying process, and an insulating coating is coated on the surface of the metal conductive particle balls by a coating process to form an insulating film with a thickness of 3%-25% of the diameter of the metal conductive particle balls, so that the insulating film softens after heating and ruptures under vertical pressure, exposing the metal conductive particles at the rupture. The metal conductive particle balls coated with the insulating film are placed in insulating glue and stirred to form an anisotropic conductive glue. The insulating glue fixes the Mini / Micro LED chip, the metal conductive particle balls and the solder pad to improve the electrical connection stability; the anisotropic conductive glue is printed on the solder pad through a hydrophobic nano-steel mesh; the Mini / Micro LED chip is mounted on the anisotropic conductive glue located on the solder pad, and the insulating film of the anisotropic conductive glue is ruptured longitudinally (in the Z-axis direction) to expose the metal conductive particle balls wrapped in the insulating film, so that the metal conductive particle balls can be respectively connected to the Mini / Micro LED chip. The LED chip and the pad contact to form a vertical conductive path, and the insulating glue of the anisotropic conductive glue is initially solidified to obtain the Mini / Micro LED. Among the many metal conductive particle balls, as long as the metal conductive particle balls are conductive, the Mini / Micro LED chip can be lit normally. It is not necessary for all metal conductive particles to be conductive at the same time. The conductive performance is good, which reduces the difficulty of welding and improves the welding quality. The insulating glue has an open time of 4 hours to 8 hours. By reheating and melting the insulating glue, the defective Mini / Micro LED chip can be easily removed and replaced with a good Mini / Micro LED chip without damaging the Mini / Micro LED chip, making the maintenance difficulty small and the maintenance cost low. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] One or more embodiments are exemplarily illustrated by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0033] Figure 1 Flowchart of a first embodiment of a method for manufacturing a Mini / Micro LED according to an embodiment of the present invention;

[0034] Figure 2 4 is a flow chart of a second embodiment of a method for manufacturing a Mini / Micro LED according to an embodiment of the present invention;

[0035] Figure 3 A partially enlarged view of a Mini / Micro LED according to an embodiment of the present invention;

[0036] Among them, 100, Mini / Micro LED; 10, substrate; 101, solder pad; 102, positive electrode solder pad; 103, negative electrode solder pad; 20, anisotropic conductive adhesive; 201, insulating glue layer; 202, insulating conductor; 203, insulating film; 204, metal conductive particle ball; 205, first avoidance port; 206, second avoidance port; 30, Mini / Micro LED chip; 301, positive electrode pin; 302, negative electrode pin; 303, chip body. DETAILED DESCRIPTION

[0037] To facilitate understanding of the present invention, the present invention is described in more detail below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly attached to the other element, or one or more elements can be interposed therebetween. When an element is described as being "connected to" another element, it can be directly connected to the other element, or one or more elements can be interposed therebetween. The terms "vertical," "horizontal," "left," "right," "inner," "outer," and similar expressions used in this specification are for illustrative purposes only. In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating relative importance or implicitly specifying the number of technical features indicated. Therefore, unless otherwise specified, features specified as "first" or "second" may explicitly or implicitly include one or more of such features; "plurality" means two or more. The term "comprising" and any variations thereof are intended to be non-exclusive, and one or more other features, integers, steps, operations, units, components, and / or combinations thereof may be present or added.

[0038] In addition, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or internal communication between two components. All technical and scientific terms used in this specification have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0039] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] For ease of understanding, the specific process of the embodiment of the present invention is described below. Figure 1 A first embodiment of a method for manufacturing a Mini / Micro LED according to an embodiment of the present invention includes:

[0041] S1. Preparing metal conductive particle balls by a mechanical separation process or a spraying process, wherein the diameter of the metal conductive particle balls is 10 μm-20 μm;

[0042] In this step, the material of the metal conductive particle balls is one or more of tin powder, silver powder, nickel powder, gold powder, tin alloy powder, copper powder, and aluminum powder, so that the metal conductive particle balls can conduct electricity.

[0043] For example, when the metal conductive particle balls are made of tin powder, the specific steps for preparing them using a mechanical separation process are as follows: heating the tin powder above its melting point to liquidize it; using a high-speed rotating disk or vibrating nozzle to divide the molten tin into tiny droplets, and controlling the rotation speed and vibration frequency of the rotating disk to control the droplet diameter to 10μm-20μm; the liquid tin droplets are sphericalized by centrifugal or mechanical forces, as molten tin naturally tends to form spheres due to surface tension; ensuring that the liquid tin droplets are rapidly cooled in air or an inert gas (such as nitrogen) to solidify into tin balls with a diameter of 10μm-20μm; using a screen or particle size classification equipment to select tin balls that meet the required size and remove unqualified tin balls, ultimately obtaining tin balls with a diameter of 10μm-20μm. The principle of the mechanical separation process for preparing tin balls is to separate molten tin metal into fine particles to form tin balls. This method typically involves mechanical force or vibration to control the size and distribution of the liquid tin droplets.

[0044] When the metal conductive particle balls are made of tin powder, the specific steps for producing them using a spraying process are as follows: The tin powder is heated above its melting point to completely melt it; the molten tin is sprayed through a nozzle while a high-pressure inert gas (such as nitrogen or argon) is used to disperse the tin stream into tiny droplets; the molten tin is introduced into a high-speed rotating disk or spray cup, where centrifugal force ejects the molten tin into tiny droplets; during the spraying process, the tin droplets rapidly cool in air or inert gas, where surface tension causes them to naturally form spheres and solidify; the cooled tin balls are recovered through a collection device and then separated through screening or grading equipment to produce balls with a diameter of 10μm-20μm. The principle of the spraying process for producing tin balls is to use a high-speed airflow or centrifugal force to break the molten tin into tiny droplets, which then form tin balls during the cooling process.

[0045] S2. Coating a layer of insulating coating on the surface of the metal conductive particle ball through a coating process and air-drying the coating to form an insulating film, wherein the thickness of the insulating film is 3%-25% of the diameter of the metal conductive particle ball;

[0046] In this step, a layer of insulating coating with a thickness of 3%-25% of the diameter of the metal conductive particle ball is coated on the surface of the metal conductive particle ball through a chemical coating process or a physical coating process, and the insulating coating is air-dried at 50°C - 80°C, and the air-drying time is 10 minutes - 30 minutes, and the air flow speed is controlled at 1m / s - 2m / s, so that the insulating coating is cured and forms an insulating film with uniform thickness, good adhesion and stable mechanical properties. At this time, the insulating film wraps the metal conductive particle ball to obtain an insulating conductor.

[0047] The insulating film is made of one or more of a resin, a polymer, or a thermoplastic polymer. For example, the resin may be epoxy resin, which has excellent mechanical strength, electrical insulation, and heat resistance. The polymer may be polyimide, which has excellent heat resistance, electrical insulation, and flexibility, making it suitable for high-temperature processes. The thermoplastic polymer may be polyethylene terephthalate, polyethylene, polypropylene, or ethylene-vinyl acetate copolymer. Polyethylene terephthalate is relatively low-cost and has good electrical properties and mechanical strength. The insulating film made of the above materials can prevent short circuits between the metal conductive particle balls, allow the metal conductive particle balls to conduct electricity along the Z-axis under a specific pressure, and protect the conductors from external environmental influences (such as oxidation). Furthermore, it ensures the positioning and pressure-bonding of the conductors during bonding, i.e., stability during hot pressing.

[0048] If the thickness of the insulating film exceeds 25%, the vertical surface may not break during extrusion. If the insulating film does not break, it will still be in an insulating state, and current cannot pass through, and the metal conductive particle balls cannot be conductive. If the insulating film is less than 3%, the insulating film is too thin, which may lead to insufficient mechanical strength of the insulating film. Therefore, the thickness of the insulating film is controlled to 3%-25% of the diameter of the metal conductive particle balls, so that under appropriate pressure and temperature conditions, the insulating film can easily break in the Z-axis direction and expose the metal conductive particle balls, allowing current to pass through the metal conductive particle balls.

[0049] For example, when the insulating film material is made of a material with a melting or softening temperature of approximately 150°C, such as polyethylene (PE), polypropylene (PP), or ethylene-vinyl acetate (EVA), during the packaging process, when the temperature rises to approximately 150°C, the insulating film softens. Due to its thinness, the insulating film may crack in the Z-axis direction under vertical pressure.

[0050] It is worth noting that the Z-axis direction is perpendicular to the surface of the substrate and consistent with the direction of the conductive path, that is, the direction in which the insulating film is broken and the metal conductive particle balls are exposed; the X-axis direction and the Y-axis direction are both parallel to the surface of the substrate, which are the directions in which insulation needs to be maintained between the metal conductive particle balls, that is, the part of the insulating film that is not broken.

[0051] S3, providing an insulating glue, placing the metal conductive particle balls coated with the insulating film into the insulating glue, and stirring to form an anisotropic conductive glue;

[0052] In this step, the insulating glue is made of modified epoxy resin, and the chemical composition of the insulating glue and the insulating film is different to prevent the insulating film from melting. The modified epoxy resin has an open time of 4 to 8 hours. The open time refers to the time window in which the glue can be operated after it is applied but has not yet fully solidified. During this 4 to 8 hour period, the Mini / Micro LED chip can be inspected. When a defective product is detected, the insulating glue can be reactivated by heating to melt it, so that the defective Mini / Micro LED chip can be easily removed without damaging the Mini / Micro LED chip and replaced with a good Mini / Micro LED chip, making the repair easier and less costly. Among them, epoxy resin is formed into modified epoxy resin through specific chemical modification, and the modified epoxy resin does not contain volatile solvents, is environmentally friendly and suitable for industrial applications; the modified epoxy resin has good conductivity after curing, and is suitable for the photovoltaic industry to replace traditional solder paste; it can be cured by heating at 150°C for 30 minutes, and the curing temperature is low; after curing, the modified epoxy resin can reach a shear strength of more than 20 MPa for materials such as stainless steel, and has high bonding strength.

[0053] The metal conductive particle balls coated with insulating film are placed in the insulating glue, and an appropriate stirring method is selected for stirring to minimize the agglomeration of the metal conductive particle balls coated with insulating film, and distribute them as evenly as possible in the insulating glue to form anisotropic conductive glue. The insulating glue not only enables the Mini / Micro LED chip to be soldered to the pad of the substrate, but also enables the Mini / Micro LED to be removed and replaced in a targeted manner after being reheated and melted, thereby reducing the difficulty and cost of maintenance.

[0054] It is worth noting that the uniformity mentioned in this application refers to relative uniformity rather than absolute uniformity.

[0055] S4, providing a hydrophobic nano-steel mesh having a plurality of steel pores and a substrate having a plurality of pads, and printing the anisotropic conductive paste onto the pads through the hydrophobic nano-steel mesh;

[0056] In this step, a substrate with several pads is provided, and steel holes are opened on the steel plate according to the distribution of the pads of the substrate to form a steel mesh. A hydrophobic nano-coating is coated on the steel mesh to prevent the anisotropic conductive adhesive from adhering to the steel holes to form a hydrophobic nano-steel mesh. The hydrophobic nano-steel mesh is placed on the substrate, and the steel holes and the pads are made to correspond one to one. Then, the anisotropic conductive adhesive is added to the surface of the hydrophobic nano-steel mesh away from the pads, and then the anisotropic conductive adhesive is evenly applied to the hydrophobic nano-steel mesh by scraping, so that the anisotropic conductive adhesive is printed onto the pads through the steel holes.

[0057] S5, peeling off the hydrophobic nano-steel mesh;

[0058] In this step, the hydrophobic nano-steel mesh is gradually separated from top to bottom or bottom to top to ensure that the anisotropic conductive adhesive filled on the pad remains intact and clear, making it easier to subsequently mount the Mini / Micro LED chip on the anisotropic conductive adhesive.

[0059] S6. Provide a Mini / Micro LED chip, mount the Mini / Micro LED chip on the anisotropic conductive adhesive located on the pad, and apply heat and pressure to longitudinally rupture the insulating film of the anisotropic conductive adhesive to expose the metal conductive particle balls wrapped in the insulating film, so that the metal conductive particle balls are in contact with the Mini / Micro LED chip and the pad respectively to form a vertical conductive path, and the insulating glue of the anisotropic conductive adhesive is initially cured to obtain a Mini / Micro LED.

[0060] In this step, the Mini / Micro LED chip is either an unpackaged Mini / Micro LED chip or a packaged Mini / Micro LED chip, and is mounted on the anisotropic conductive adhesive located on the pad through a mass transfer process or an SMT process. Since the anisotropic conductive adhesive is directly applied to the pad through a hydrophobic nano-steel mesh, no separate dispensing process is required, saving process steps and reducing costs. The unpackaged Mini / Micro LED chip or the packaged Mini / Micro LED chip located on the anisotropic conductive adhesive is then heated and pressurized. When heated to 120°C-250°C, the insulating film of the anisotropic conductive adhesive softens. Under the action of vertical mechanical pressure, excess insulating glue overflows, and the insulating film ruptures in the Z-axis direction, thereby exposing the metal conductive particle balls wrapped in the insulating film. The metal conductive particle balls are flattened under the vertical mechanical force and arranged in a neat row, and the metal conductive particle balls are respectively aligned with the Mini / Micro LED. The LED chip and the pad come into contact to form a conductive path. After heating for a certain period of time, the insulating glue of the anisotropic conductive adhesive begins to solidify, resulting in a Mini / Micro LED.

[0061] In this embodiment, metal conductive particle balls with a diameter of 10μm-20μm are prepared by a mechanical separation process or a spraying process, and an insulating coating is applied to the surface of the metal conductive particle balls by a coating process to form an insulating film with a thickness of 3%-25% of the diameter of the metal conductive particle balls. The insulating film is softened when heated to 120°C-250°C and ruptured under vertical pressure, exposing the metal conductive particles at the rupture. The metal conductive particle balls coated with the insulating film are placed in an insulating glue and stirred to form an anisotropic conductive glue. The insulating glue fixes the Mini / Micro LED chip, the metal conductive particle balls, and the pad, thereby improving the stability of the electrical connection. The anisotropic conductive glue is printed on the pad using a hydrophobic nano-steel mesh. The Mini / Micro LED chip is mounted on the anisotropic conductive glue located on the pad, and the insulating film of the anisotropic conductive glue is ruptured longitudinally (in the Z-axis direction) to expose the metal conductive particle balls wrapped in the insulating film, so that the metal conductive particle balls can be respectively connected to the Mini / Micro LED chip. The LED chip and the pad contact to form a vertical conductive path, and the insulating glue of the anisotropic conductive glue is initially solidified to obtain the Mini / Micro LED. Among the many metal conductive particle balls, as long as the metal conductive particle balls are conductive, the Mini / Micro LED chip can be lit normally. It is not necessary for all metal conductive particles to be conductive at the same time. The conductive performance is good, which reduces the difficulty of welding and improves the welding quality. The insulating glue has an open time of 4 hours to 8 hours. By reheating and melting the insulating glue, the defective Mini / Micro LED chip can be easily removed and replaced with a good Mini / Micro LED chip without damaging the Mini / Micro LED chip, making the maintenance difficulty small and the maintenance cost low.

[0062] See also Figure 2 As shown, the present invention also discloses a second embodiment of a method for manufacturing Mini / Micro LEDs, including:

[0063] S10, preparing metal conductive particle balls by a mechanical separation process or a spraying process, wherein the diameter of the metal conductive particle balls is 10 μm-20 μm;

[0064] In this step, the description of the above step S10 refers to S1 of the first embodiment, and this step will not be described in detail.

[0065] S11, immersing the metal conductive particle balls in a chemical solution by chemical deposition, forming an insulating coating on the surface of the metal conductive particle balls through a chemical reaction, and air-drying the insulating coating to form an insulating film; or, depositing a material for the insulating coating on the surface of the metal conductive particle balls by physical vapor deposition to form an insulating coating, and air-drying the insulating coating to form an insulating film;

[0066] In this step, the chemical deposition method is a chemical reduction process that uses a suitable reducing agent to reduce the metal ions in the plating solution and deposit them on the surface of the substrate. Specifically, the metal conductive particle balls are immersed in a chemical solution, so that the metal ions in the insulating coating material are reduced and deposited on the surface of the metal conductive particle balls, forming an insulating coating with a thickness of 3%-25% of the diameter of the metal conductive particle balls. The insulating coating is then air-dried at 50°C-80°C for 10-30 minutes at an airflow rate of 1m / s-2m / s, so that the insulating coating solidifies and forms an insulating film with uniform thickness, good adhesion, and stable mechanical properties. The insulating film then wraps around the metal conductive particle balls.

[0067] Physical vapor deposition is a method that uses physical methods (such as evaporation and sputtering) to vaporize the coating material and deposit it on the surface of the substrate to form a film. Specifically, in a vacuum environment, the insulating coating material is deposited on the surface of the metal conductive particle balls by evaporation or sputtering, forming an insulating coating with a thickness of 3%-25% of the diameter of the metal conductive particle balls. The insulating coating is then air-dried at 50°C to 80°C for 10 to 30 minutes at an airflow rate of 1m / s to 2m / s, allowing the insulating coating to solidify and form an insulating film with uniform thickness, good adhesion, and stable mechanical properties. The insulating film then wraps around the metal conductive particle balls.

[0068] The insulating film can not only make the metal conductive particle balls contact with the pads of the Mini / Micro LED chip and the substrate respectively to form a vertical conductive path, but also prevent two adjacent metal conductive particle balls from short-circuiting in the X-axis and Y-axis directions, that is, the insulation effect. Since the two adjacent metal conductive particle balls are insulated in the X-axis and Y-axis directions, even if multiple Mini / Micro LED chips are used as a collection, it will not cause a short circuit between two adjacent Mini / Micro LED chips. Therefore, when designing the steel holes of the hydrophobic nano-steel mesh, the diameter of the steel holes can be designed to be larger than the size of a pad on the substrate (one pad corresponds to one Mini / Micro LED chip). Specifically, the diameter of the steel holes can be designed to accommodate the size of three pads. Since the diameter of the steel holes at this time is 2 times larger than the diameter of the steel holes that accommodate one pad, when printing anisotropic conductive adhesive, the anisotropic conductive adhesive is easier to fill into the pad through the steel holes, making it more suitable for welding Mini / Micro LED chips with small pixels, and used in ultra-high-resolution Mini / Micro The LED display screen can of course also design the diameter of the steel hole to accommodate the size of two, four, five, six pads, etc. This embodiment does not impose a specific limit on the number of pads that the diameter of the steel hole can be designed to accommodate.

[0069] S12, providing an insulating glue, placing the metal conductive particle balls coated with the insulating film into the insulating glue, and stirring at a low speed so that the plurality of metal conductive particle balls are evenly distributed in the insulating glue to form an anisotropic conductive glue; or,

[0070] Providing an insulating glue, placing metal conductive particle balls coated with the insulating film into the insulating glue, and stirring the metal conductive particle balls by a planetary mixer using a combined rotation and revolution motion so that the plurality of metal conductive particle balls are evenly distributed in the insulating glue to form an anisotropic conductive glue;

[0071] In this step, an insulating glue with a certain viscosity and consistency is provided, and the consistency of the insulating glue must ensure the bonding performance while making the metal conductive particle balls wrapped with the insulating film easier to disperse; the metal conductive particle balls wrapped with the insulating film are placed in the insulating glue and stirred by a low-speed stirring method. The low-speed stirring method can reduce the aggregation of the metal conductive particle balls wrapped with the insulating film and the generation of bubbles, which helps to evenly distribute the metal conductive particle balls wrapped with the insulating film in the insulating glue. A dispersant can also be added to the insulating glue. The dispersant can reduce the interaction between the metal conductive particle balls wrapped with the insulating film and reduce agglomeration. The dispersant can be a surfactant or an organic solvent.

[0072] In addition to the low-speed stirring method, a planetary stirring method can also be used. The metal conductive particle balls wrapped with the insulating film are stirred by the combined motion of rotation and revolution of the planetary mixer, so that the metal conductive particle balls wrapped with the insulating film are more evenly distributed.

[0073] Because the current driving a single Mini / Micro LED chip is very small, the maximum driving current for each Mini / Micro LED chip is typically less than 3-5mA. In many cases, the driving current is as little as a few tenths of a milliampere during normal operation. Therefore, as long as the metal conductive particle balls can touch the bonding pads of the Mini / Micro LED chip and the bonding pads of the substrate, current conduction can be established, and the Mini / Micro LED chip can be properly illuminated.

[0074] Therefore, under such low current requirements, even if some solder balls do not fully contact the pads during soldering, it will not affect the normal power supply and lighting of the chip. However, to ensure long-term stability and reliability, it is necessary to ensure that all solder balls can make good contact with the pads. Therefore, due to the viscosity and consistency of the glue, the metal conductive particle balls wrapped in the insulating film may have a small amount of adhesion. However, this small amount of adhesion does not affect the basic working principle of the metal conductive particle balls.

[0075] The steps of S4 include:

[0076] S13, providing a steel plate, and opening steel holes on the steel plate corresponding to the welding pads of the substrate to form a steel mesh;

[0077] S14, coating a layer of nano-hydrophobic coating on the steel mesh to obtain a hydrophobic nano-steel mesh;

[0078] S15, providing a substrate having a plurality of pads, placing the hydrophobic nano-steel mesh on the substrate, and aligning the mesh so that each of the steel holes is aligned with each of the pads;

[0079] S16, adding the anisotropic conductive adhesive to the side of the hydrophobic nano-steel mesh away from the pad, and evenly scraping the anisotropic conductive adhesive on the hydrophobic nano-steel mesh so that the anisotropic conductive adhesive is printed onto the pad through the steel holes.

[0080] In this step, the substrate can be one of a circuit board or a glass substrate, and the printing of the anisotropic conductive adhesive is completed by a steel screen printer. First, a hydrophobic nano steel mesh is prepared. Specifically, a steel plate is provided, and steel holes of the same size as the pads are opened on the steel plate corresponding to the pad positions of the substrate, and the distribution of the steel holes is the same as the distribution of the pads to obtain a steel mesh; a layer of nano hydrophobic coating is applied to the steel mesh to obtain a hydrophobic nano steel mesh. Among them, the nano hydrophobic coating can be a fluoride-based nano coating, a silane-based nano coating or a nano silica coating. Exemplarily, the fluoride-based nano coating material is polytetrafluoroethylene or a perfluoroalkyl silane compound. The fluoride-based nano coating has extremely high hydrophobicity, and the water contact angle can reach 120°-150°, which keeps the surface of the hydrophobic nano steel mesh clean and improves printing accuracy; it has extremely low surface energy, prevents anisotropic conductive adhesive from adhering to the steel holes of the hydrophobic nano steel mesh, reduces clogging, and extends the service life of the hydrophobic nano steel mesh; it has excellent corrosion resistance and chemical stability. Silane-based nanocoatings, made from octyltriethoxysilane or methyltrichlorosilane, exhibit excellent hydrophobicity, with water contact angles reaching 110°-130°. This prevents anisotropic conductive adhesives from adhering to the pores of hydrophobic nanosteel meshes. They also possess strong chemical bonding, resulting in a stable and wear-resistant coating. They are easy to process and prepare, exhibit excellent adhesion, and are suitable for forming a long-lasting, effective anti-sticking layer on steel mesh surfaces. Nanosilica coatings also exhibit excellent hydrophobicity, with properties that can be enhanced through chemical modification. They also offer excellent wear resistance and thermal stability, and are relatively low-cost, making them suitable for mass-produced steel mesh surface treatments.

[0081] After the hydrophobic nano-steel mesh and the substrate are prepared, the substrate is first mounted on the fixture of the stencil printer. The fixture has adjustable supports and positioning pins to ensure the accurate position of the substrate. The hydrophobic nano-steel mesh is then fixed to the frame of the printer. The printer's visual positioning system automatically detects the positioning mark (FiducialMark) of the substrate for correction, so that the position of the substrate and the hydrophobic nano-steel mesh are aligned, and each steel hole is aligned with each pad, that is, each steel hole is located directly below each pad. The substrate is then fixed to the printing platform by vacuum adsorption or mechanical clamping to prevent movement during the printing process. The stencil printer's squeegee (usually made of metal or polyurethane) pushes the anisotropic conductive adhesive onto the surface of the hydrophobic nano-steel mesh and applies it along the mesh at a set speed and pressure. The squeegee moves back and forth across the mesh, squeezing the adhesive through the mesh's pores and onto the substrate's pads. This ensures a consistent level of adhesive on the pads, with any excess adhesive collected by the squeegee and returned to the surface above the mesh. After the adhesive is applied, the stencil printer's control system slowly lifts the mesh, gradually separating it from the substrate. The squeegee speed is 20-100 mm / s, the pressure is 0.5-1.5 kg, and the printing environment is kept clean and dry, with humidity below 60%.

[0082] S17, peeling off the hydrophobic nano-steel mesh;

[0083] In this step, the description of the above step S18 refers to S5 of the first embodiment, and this step will not be repeated.

[0084] The steps of S6 include:

[0085] S18. Mounting the Mini / Micro LED chip onto the anisotropic conductive adhesive on the pad using a mass transfer process or a SMT process;

[0086] S19. The Mini / Micro LED chip mounted on the anisotropic conductive adhesive on the pad is heated through a hot pressing process and pressure is applied in the longitudinal direction of the Mini / Micro LED chip, so that the insulating film of the anisotropic conductive adhesive is softened and ruptured in the Z-axis direction to expose the metal conductive particle balls wrapped in the insulating film. The metal conductive particle balls are compressed and contact the Mini / Micro LED chip and the pad respectively to form a vertical conductive path, and the insulating glue of the anisotropic conductive adhesive is initially cured to obtain a Mini / Micro LED.

[0087] In this step, mass transfer process or standard SMT process is adopted according to different mounting objects.

[0088] When mounting unpackaged Mini / Micro LED chips, a mass transfer process can be used. Specifically, a transfer head equipped with an elastic mold or electromagnetic suction head is used to pick up Mini / Micro LED chips in batches from a temporary carrier. A visual recognition system is used to precisely align the picked Mini / Micro LED chips with the anisotropic conductive adhesive on the pads. The Mini / Micro LED chips are then released onto the anisotropic conductive adhesive. The alignment accuracy is ±1μm to 2μm, the release pressure is 0.2MPa to 1.0MPa, and the temperature is 80°C to 150°C. The mass transfer process can transfer and precisely mount Mini / Micro LED chips in large quantities from their carriers onto the anisotropic conductive adhesive on the pads, improving mounting efficiency, saving time, reducing costs, and ensuring high-quality electrical connections and mechanical strength.

[0089] When mounting packaged Mini / Micro LED chips, standard SMT processes are used to mount the packaged Mini / Micro LED chips onto the anisotropic conductive adhesive on the pads. Specifically, a transfer head with an elastic mold or electromagnetic suction head is used to pick up the packaged Mini / Micro LED chips using a placement machine. The placement machine's vision system precisely aligns the packaged Mini / Micro LED chips with the anisotropic conductive adhesive on the pads, precisely placing the packaged Mini / Micro LED chips on the anisotropic conductive adhesive to ensure high-quality electrical connections and mechanical strength.

[0090] The hot pressing process is to apply pressure while heating. Specifically, the Mini / Micro LED chip mounted on the anisotropic conductive adhesive on the pad is heated, and pressure is applied in the longitudinal direction of the Mini / Micro LED chip. When heated to 120℃-250℃, the insulating film of the anisotropic conductive adhesive softens. Then, a vertical uniform pressure of 30N·m-100N·m is applied to the Mini / Micro LED chip through a flat pressure plate, causing the softened insulating film to rupture in the Z-axis direction, forming a first avoidance and a second avoidance. Since the insulating film wraps the metal conductive particle balls, when the insulating film ruptures, the metal conductive particle balls are exposed through the first avoidance and the second avoidance. The exposed metal conductive particle balls are respectively adjacent to the Mini / Micro The LED chip and the pad contact to form a vertical conductive path. Since the insulating film is not cracked in the X-axis and Y-axis directions, and after curing, it is prevented from being damaged by external force or environmental influences during use, and the short circuit caused by contact between two adjacent metal conductive particle balls in the X-axis and Y-axis directions is avoided, which plays a role in forming permanent insulation in the X-axis and Y-axis directions. Under pressure, the Mini / Micro LED chip, metal conductive particle ball and pad are in closer contact, thereby improving the stability of the electrical connection.

[0091] One Mini / Micro LED chip is soldered to one pad, and the current required to drive a single Mini / Micro LED chip is very small. The maximum driving current of each Mini / Micro LED chip is usually less than 3-5mA. In normal operation, the driving current is often only a few tenths of a milliampere.

[0092] The current required to drive a single Mini / Micro LED chip is very small, and the anisotropic conductive adhesive on a pad contains multiple metal conductive particle balls, and a Mini / Micro LED chip is soldered to one pad. Therefore, as long as one or two of the multiple metal conductive particle balls are conductive, the Mini / Micro LED chip can be lit normally. It is not necessary for all metal conductive particles to be conductive at the same time, which reduces the difficulty of welding and improves the welding quality.

[0093] S20, testing the Mini / Micro LED chip;

[0094] In this step, since it takes 4 to 8 hours for the insulating glue to completely cure, that is, the insulating glue is in a preliminary curing state during 4 to 8 hours, the insulating glue has an open time of 4 to 8 hours, so the Mini / Micro LED chip can be tested within this time.

[0095] S21. When the Mini / Micro LED chip is defective, heat the Mini / Micro LED chip to melt the anisotropic conductive adhesive, remove the defective Mini / Micro LED chip, and replace it with a good Mini / Micro LED chip.

[0096] In this step, when the Mini / Micro LED chip is detected to be defective, the anisotropic conductive glue can be reactivated by heating it to 120°C-250°C to melt the insulating glue. The junction temperature of the Mini / Micro LED chip is 125°C-150°C. Therefore, a heating temperature of 120°C-250°C can not only remelt the insulating glue, but also will not damage the Mini / Micro LED chip; after the insulating glue is melted, the defective Mini / Micro LED chip can be easily removed and replaced with a good Mini / Micro LED chip. The insulating glue has an open time of 4 hours to 8 hours, so that during maintenance, defective products can be repaired and replaced, making maintenance less difficult, ensuring that the product yield is close to 100%, avoiding scrapping of the entire substrate or display module, and low maintenance costs. The insulating glue has an open time of 4 to 8 hours, allowing defective Mini / Micro LED chips to be repaired by heating within the open time, ensuring a product yield close to 100% and avoiding scrapping of the entire substrate or display module. If problems are discovered after curing, the entire substrate or display module may be scrapped. Repairing within the open time greatly reduces production waste and material loss, allowing the production line to flexibly handle quality inspection and repair, reducing the risk of batch scrapping.

[0097] The open time of the insulating glue can also be adjusted by adding specific chemical materials to the insulating glue; for example, the material that extends the open time can be a retardant or a plasticizer; the material that accelerates curing can be a catalyst or an initiator; it is also possible to use a moisture-curing glue so that the insulating glue gradually cures by absorbing moisture (humidity) in the air.

[0098] Among them, the Mini / Micro LED chips can be blue Mini / Micro LED chips, green Mini / Micro LED chips and red Mini / Micro LED chips. The maximum junction temperature of the blue Mini / Micro LED chips and the green Mini / Micro LED chips is 150°C. At this temperature, even if they are heated continuously for 30 minutes, it will not have a significant impact on the lifespan of the blue Mini / Micro LED chips and the green Mini / Micro LED chips; the maximum junction temperature of the red Mini / Micro LED chips is 125°C. Laboratory tests show that hot pressing at 150°C for 30 minutes will not significantly affect the lifespan of the red Mini / Micro LED chips; of course, the heating temperature and heating time are coordinated with each other. When heated to 250°C, the heating time is 1 second to 8 seconds; when heated to 150°C, the heating time is 30 minutes to ensure that the anisotropic conductive adhesive can be heated to reactivate the insulating glue, so that the insulating glue melts without damaging the Mini / Micro LED chips; however, when the heating temperature exceeds 250°C and the heating time exceeds 10 seconds, the Mini / Micro LED chips may be damaged.

[0099] In this embodiment, metal conductive particle balls with a diameter of 10μm-20μm are prepared by a mechanical separation process or a spraying process, and an insulating coating is applied to the surface of the metal conductive particle balls by a coating process to form an insulating film with a thickness of 3%-25% of the diameter of the metal conductive particle balls. The insulating film is softened when heated to 120°C-250°C and ruptured under vertical pressure, exposing the metal conductive particles at the rupture. The metal conductive particle balls coated with the insulating film are placed in an insulating glue and stirred to form an anisotropic conductive glue. The insulating glue fixes the Mini / Micro LED chip, the metal conductive particle balls, and the pad, thereby improving the stability of the electrical connection. The anisotropic conductive glue is printed on the pad using a hydrophobic nano-steel mesh. The Mini / Micro LED chip is mounted on the anisotropic conductive glue located on the pad, and the insulating film of the anisotropic conductive glue is ruptured longitudinally (in the Z-axis direction) to expose the metal conductive particle balls wrapped in the insulating film, so that the metal conductive particle balls can be respectively connected to the Mini / Micro LED chip. The LED chip and the pad contact to form a vertical conductive path, and the insulating glue of the anisotropic conductive glue is initially solidified to obtain the Mini / Micro LED. Among the many metal conductive particle balls, as long as the metal conductive particle balls are conductive, the Mini / Micro LED chip can be lit normally. It is not necessary for all metal conductive particles to be conductive at the same time, which reduces the difficulty of welding and improves the welding quality. The insulating glue has an open time of 4 hours to 8 hours. By reheating and melting the insulating glue, the defective Mini / Micro LED chip can be easily removed and replaced with a good Mini / Micro LED chip without damaging the Mini / Micro LED chip, making maintenance easier and lowering the cost.

[0100] like Figure 3 As shown, an embodiment of the present invention further discloses a Mini / Micro LED, which is manufactured by the manufacturing method of any of the above embodiments. The manufacturing method of any of the above embodiments can produce a Mini / Micro LED, wherein the Mini / Micro LED 100 includes a substrate 10, multiple anisotropic conductive adhesives 20 and multiple Mini / Micro LED chips 30, and the Mini / Micro LED chips 30 are electrically connected to the substrate 10 through the anisotropic conductive adhesive 20.

[0101] The substrate 10 may be a circuit board or a glass substrate 10 . A plurality of pads 101 are provided on the substrate 10 , wherein the pads 101 include a positive electrode pad 102 and a negative electrode pad 103 .

[0102] A plurality of anisotropic conductive adhesives 20 are provided at positions corresponding to the plurality of pads 101, and each anisotropic conductive adhesive 20 is correspondingly provided on each pad 101. Each anisotropic conductive adhesive 20 includes an insulating glue layer 201 and a plurality of insulating conductors 202. The insulating glue layer 201 is connected to the substrate 10 and the Mini / Micro LED chip 30 respectively. The plurality of insulating conductors 202 are all provided in the insulating glue layer 201. The insulating glue layer 201 is fixedly connected to the substrate 10 and the Mini / Micro LED chip 30 respectively, and a third avoidance opening and a fourth avoidance opening are provided at the top and bottom of the insulating glue layer 201 corresponding to each insulating conductor 202, so that one end of the insulating conductor 202 can be electrically connected to the pad 101 through the fourth avoidance opening, and the material of the insulating glue layer 201 is a modified epoxy resin, so that the insulating glue layer 201 not only achieves insulation in the X-axis direction and the Y-axis direction to avoid short circuit, but also plays the role of isolating the Mini / Micro The connection function of the LED chip 30 fixed on the solder pad 101 also enables the insulating conductor 202 to be conductive in the Z-axis direction.

[0103] The Mini / Micro LED chip 30 can be either an unpackaged Mini / Micro LED chip 30 or a packaged Mini / Micro LED chip 30. Multiple Mini / Micro LED chips 30 are disposed corresponding to the multiple anisotropic conductive adhesives 20, with each Mini / Micro LED chip 30 disposed on each anisotropic conductive adhesive 20. The other end of the insulating conductor 202 is electrically connected to the Mini / Micro LED chip 30 via a third escape opening. Because multiple insulating conductors 202 are disposed in one anisotropic conductive adhesive 20, only one or two insulating conductors 202 are electrically connected to the Mini / Micro LED chip 30 and the solder pad 101. This allows the Mini / Micro LED chip 30 to properly illuminate, ensuring stable conductivity. This eliminates the need for all metal conductive particles to be conductive simultaneously, reducing soldering difficulty and ensuring consistent soldering quality. Furthermore, the more conductive metal particles that are conductive, the more stable the conductive performance and the longer the service life.

[0104] Furthermore, the insulating conductor 202 includes an insulating film 203 and a metal conductive particle ball 204. The outer surface of the metal conductive particle ball 204 is covered with an insulating film 203. The top and bottom of the insulating film 203 are respectively provided with a first avoidance opening 205 and a second avoidance opening 206, so that the top of the metal conductive particle ball 204 can be exposed and electrically connected to the Mini / Micro LED chip 30 through the first avoidance opening 205, and the bottom of the metal conductive particle ball 204 can be exposed and electrically connected to the pad 101 of the substrate 10 through the second avoidance opening 206, thereby achieving conduction in the Z-axis direction and insulation in the X-axis and Y-axis directions to avoid short circuit; and multiple insulating conductors 202 are provided between a Mini / Micro LED chip 30 and the pad 101, so that only one or two insulating conductors 202 are electrically connected to the Mini / Micro LED chip 30 and the pad 101 to normally light up the Mini / Micro LED chip 30, avoiding unstable conductivity caused by cold soldering.

[0105] Specifically, the material of the metal conductive particle balls 204 is one of tin powder, silver powder, nickel powder, gold powder, tin alloy powder, copper powder, and aluminum powder. Preferably, the material of the metal conductive particle balls 204 is tin powder, which has good conductivity. The material of the insulating film 203 is one of resin, polymer or thermoplastic polymer, and the chemical composition of the material of the insulating film 203 is different from that of the material of the insulating glue layer 201, so as to prevent the insulating film 203 from being melted by the insulating glue layer 201 during heating. The insulating film 203 is coated on the surface of the metal conductive particle ball 204, and the thickness of the insulating film 203 is 3%-25% of the diameter of the metal conductive particle ball 204, so that the thickness of the insulating film 203 is relatively thin. During the manufacturing process, the insulating film 203 is easy to soften when heated, and the insulating film 203 is easy to break in the Z-axis direction under vertical pressure, forming a first avoidance port 205 and a second avoidance port 206, so that the Mini / Micro LED 100 can be turned on in the Z-axis direction and permanently insulated in the X-axis and Y-axis directions to avoid short circuits.

[0106] Furthermore, the pad 101 includes a positive pad 102 and a negative pad 103, and the positive pad 102 and the negative pad 103 are both arranged on the same surface of the substrate 10 and are arranged toward the Mini / Micro LED chip 30. The Mini / Micro LED chip 30 includes a positive pin 301, a negative pin 302 and a chip body 303, and the positive pin 301 and the negative pin 302 are both arranged on the same surface of the chip body 303 and are arranged toward the positive pad 102 and the negative pad 103. The positive pin 301 is electrically connected to the metal conductive particle ball 204 through the first avoidance port 205, and the positive pad 102 is electrically connected to the metal conductive particle ball 204 through the second avoidance port 206, that is, the positive pin 301 is electrically connected to the positive pad 102 through the metal conductive particle ball 204; the negative pin 302 is in contact with the metal conductive particle ball 204 through the first avoidance port 205 To achieve electrical connection, the negative electrode pad 103 is electrically connected to the metal conductive particle ball 204 through the second avoidance port 206, and the negative electrode pin 302 is electrically connected to the negative electrode pad 103 through the metal conductive particle ball 204, and the diameter of the metal conductive particle ball 204 is 10μm-20μm, and the thickness of the insulating film 203 is 3%-25% of the diameter of the metal conductive particle ball 204, so that the insulating conductor 202 is small in size. Therefore, there are multiple insulating conductors 202 between the positive electrode pin 301 and the positive electrode pad 102, and there are multiple insulating conductors 202 between the negative electrode pin 302 and the negative electrode pad 103, and each Mini / Micro The maximum driving current of the LED chip 30 is usually less than 3-5mA. In normal operation, the driving current is often even only a few tenths of a milliampere. Therefore, only one insulating conductor 202 is required to be electrically connected to the positive pin 301 and the positive pad 102 at the same time. Similarly, only one insulating conductor 202 is required to be electrically connected to the negative pin 302 and the negative pad 103. This allows the Mini / Micro LED chip 30 to light up normally. The conductivity is good, and all insulating conductors 202 do not need to be turned on at the same time, which reduces the difficulty of welding and ensures stable welding quality.

[0107] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the present invention as described above. For the sake of simplicity, they are not provided in detail. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that it is still possible to modify the technical solutions described in the above embodiments, or to make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing Mini / Micro LED, characterized in that: The manufacturing method comprises: The metal conductive particle balls are prepared by a mechanical separation process or a spraying process, wherein the diameter of the metal conductive particle balls is 10 μm-20 μm; The metal conductive particle balls are immersed in a chemical solution by a chemical deposition method, an insulating coating is formed on the surface of the metal conductive particle balls by a chemical reaction, and the insulating coating is air-dried to form an insulating film, wherein the thickness of the insulating film is 3% to 25% of the diameter of the metal conductive particle balls; Providing an insulating glue, placing the metal conductive particle balls coated with the insulating film into the insulating glue, and stirring to form an anisotropic conductive glue; Providing a hydrophobic nano-steel mesh having a plurality of steel pores and a substrate having a plurality of pads, and printing the anisotropic conductive adhesive onto the pads through the hydrophobic nano-steel mesh so that the anisotropic conductive adhesive on one pad has a plurality of metal conductive particle balls; peeling off the hydrophobic nano-steel mesh; A Mini / Micro LED chip is provided, and the Mini / Micro LED chip is mounted on an anisotropic conductive adhesive located on the pad. Heat and pressure are applied to longitudinally rupture the insulating film of the anisotropic conductive adhesive, exposing metal conductive particle balls wrapped in the insulating film. The metal conductive particle balls are respectively in contact with the Mini / Micro LED chip and the pad to form a vertical conductive path. The insulating adhesive of the anisotropic conductive adhesive is initially cured to obtain a Mini / Micro LED. The insulating adhesive is made of a modified epoxy resin with an open time of 4-8 hours. The Mini / Micro LED chip is inspected; when the Mini / Micro LED chip is defective, the Mini / Micro LED chip is heated to melt the anisotropic conductive adhesive, and the defective Mini / Micro LED chip is removed and replaced with a good Mini / Micro LED chip.

2. The manufacturing method according to claim 1, characterized in that The insulating film is made of resin.

3. The manufacturing method according to claim 1, characterized in that The material of the metal conductive particle balls is one or more of tin powder, silver powder, nickel powder, gold powder, tin alloy powder, copper powder, and aluminum powder.

4. The manufacturing method according to claim 1, characterized in that The steps of providing a Mini / Micro LED chip, attaching the Mini / Micro LED chip to the anisotropic conductive adhesive located on the pad, applying heat and pressure to longitudinally rupture the insulating film of the anisotropic conductive adhesive to expose the metal conductive particle balls wrapped in the insulating film, so that the metal conductive particle balls respectively contact the Mini / Micro LED chip and the pad to form a vertical conductive path, and initially curing the insulating adhesive of the anisotropic conductive adhesive to obtain the Mini / Micro LED are formed in two steps, including: Mounting the Mini / Micro LED chip onto the anisotropic conductive adhesive on the pad through a mass transfer process or a SMT process; The Mini / Micro LED chip mounted on the anisotropic conductive adhesive on the pad is heated through a hot pressing process and pressure is applied in the longitudinal direction of the Mini / Micro LED chip, so that the insulating film of the anisotropic conductive adhesive softens and breaks in the Z-axis direction to expose the metal conductive particle balls wrapped in the insulating film. The metal conductive particle balls are compressed and contact the Mini / Micro LED chip and the pad respectively to form a vertical conductive path, and the insulating glue of the anisotropic conductive adhesive is initially cured to obtain a Mini / Micro LED.

5. The manufacturing method according to claim 1, characterized in that The steps of providing an insulating glue, placing the metal conductive particle balls coated with the insulating film into the insulating glue, and stirring the mixture to form an anisotropic conductive glue include: An insulating glue is provided, metal conductive particle balls coated with the insulating film are placed in the insulating glue, and the metal conductive particle balls are evenly distributed in the insulating glue by low-speed stirring, thereby forming an anisotropic conductive glue; or, an insulating glue is provided, metal conductive particle balls coated with the insulating film are placed in the insulating glue, and the metal conductive particle balls are evenly distributed in the insulating glue by a planetary mixer through a combined motion of rotation and revolution, thereby forming an anisotropic conductive glue.

6. The manufacturing method according to claim 1, characterized in that The step of providing a hydrophobic nano-steel mesh having a plurality of steel pores comprises: A steel plate is provided, and steel holes are opened on the steel plate corresponding to the welding pads of the substrate to form a steel mesh; a layer of nano-hydrophobic coating is coated on the steel mesh to obtain a hydrophobic nano-steel mesh.

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