Mini / Micro LED and manufacturing method thereof

Abstract

The invention relates to the technical field of LED display, and discloses a Mini / Micro LED and a manufacturing method thereof. The manufacturing method comprises the following steps: preparing metal conductive particle balls through a mechanical separation process or a spraying process; coating an insulating coating on the surface of the metal conductive particle ball and air-drying to form an insulating film; putting the metal conductive particle balls coated with the insulating films into provided insulating glue and stirring to form anisotropic conductive glue; printing anisotropic conductive adhesive on a bonding pad of the provided substrate through the provided hydrophobic nano steel mesh; stripping the hydrophobic nano steel mesh; the provided Mini / Micro LED chip is mounted on the anisotropic conductive adhesive located on the bonding pad, the insulating film is longitudinally broken by heating and pressurizing to expose the 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 bonding pad to form a vertical conductive path, and the insulating adhesive is preliminarily cured to obtain the Mini / Micro LED, so that stable welding quality is realized; and the maintenance difficulty and the maintenance cost are low.

Description

Technical Field

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

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

[0003] 2) In addition, when a chip is defective, we need to heat the PCB or glass substrate to a higher 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 will quickly transfer to the surrounding chips, making it difficult to accurately apply the heating area to the damaged chip, which will cause damage to the normal chips nearby, increasing the risk during the repair process.

[0004] 3) Since the ACF is a whole conductive film, if there is a poor connection or failure of individual chips, it is extremely difficult to repair. Because thousands of chips are already connected to the film, repair often requires replacing the entire conductive film, resulting in all chips on the ACF film being scrapped and high repair costs. Summary of the invention

[0005] 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.

[0006] To achieve the above object, the present invention provides a method for manufacturing Mini / Micro LED, 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; A layer of insulating coating is applied on the surface of the metal conductive particle ball by a coating process, and air-dried to form an insulating film, wherein the thickness of the insulating film is 3%-25% of the diameter of the metal conductive particle ball; 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 holes and a substrate having a plurality of pads, and printing the anisotropic conductive glue onto the pads through the hydrophobic nano-steel mesh; peeling off the hydrophobic nano-steel mesh; A Mini / Micro LED chip is provided, and the Mini / Micro LED chip is mounted on the anisotropic conductive adhesive located on the pad, and heating and pressurizing are performed 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 respectively in contact with the Mini / Micro LED chip and the pad to form a vertical conductive path, and the insulating glue of the anisotropic conductive adhesive is initially cured to obtain a Mini / Micro LED.

[0007] 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.

[0008] Furthermore, in one embodiment, the material of the metal conductive particle ball is one or more of tin powder, silver powder, nickel powder, gold powder, tin alloy powder, copper powder, and aluminum powder.

[0009] Further, 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, heating and pressurizing the anisotropic conductive adhesive 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 respectively in contact with the Mini / Micro LED chip and the pad to form a vertical conductive path, and the insulating glue of the anisotropic conductive adhesive is initially cured to obtain the Mini / Micro LED, the method further includes: Testing the Mini / Micro LED chip; When the Mini / Micro LED chip is defective, the Mini / Micro LED chip is heated to melt the anisotropic conductive adhesive, 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.

[0010] Further, in one embodiment, the step of providing a Mini / Micro LED chip, mounting the Mini / Micro LED chip on the anisotropic conductive adhesive on the pad, heating and pressurizing the anisotropic conductive adhesive 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 respectively in contact with the Mini / Micro LED chip and the pad to form a vertical conductive path, and preliminarily solidifying the insulating glue of the anisotropic conductive adhesive to obtain the Mini / Micro LED is 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 located 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, and 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.

[0011] 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 comprises: 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.

[0012] 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 comprises: The material of the insulating coating 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.

[0013] 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 comprises: An insulating glue is provided, and metal conductive particle balls coated with the insulating film are placed in the insulating glue, and a plurality of the metal conductive particle balls are evenly distributed in the insulating glue by low-speed stirring to form an anisotropic conductive glue; or, an insulating glue is provided, and metal conductive particle balls coated with the insulating film are placed in the insulating glue, and a combination of rotation and revolution of a planetary mixer is used to stir the metal conductive particle balls so that a plurality of the metal conductive particle balls are evenly distributed in the insulating glue to form an anisotropic conductive glue.

[0014] Further, in one embodiment, the step of providing a hydrophobic nano steel mesh having a plurality of steel pores comprises: 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; A layer of nano hydrophobic coating is coated on the steel mesh to obtain a hydrophobic nano steel mesh.

[0015] The present invention also provides a Mini / Micro LED, which is manufactured by the manufacturing method.

[0016] In the technical solution provided by the present invention, a metal conductive particle ball with a diameter of 10μm-20μm is prepared by a mechanical separation process or a spraying process, and a layer of insulating coating is coated on the surface of the metal conductive particle ball by a coating process to form an insulating film with a thickness of 3%-25% of the diameter of the metal conductive particle ball, so that the insulating film softens after heating and ruptures under the action of vertical pressure, and the metal conductive particles are exposed at the rupture. The metal conductive particle ball coated with the insulating film is placed in insulating glue and stirred to form an anisotropic conductive glue, and the insulating glue fixes and connects the Mini / Micro LED chip, the metal conductive particle ball and the pad to improve the electrical connection stability; the anisotropic conductive glue is printed on the pad through a hydrophobic nano steel mesh; the Mini / Micro LED chip is mounted on the anisotropic conductive glue located on the pad, and the heating and pressurization are performed to cause the insulating film of the anisotropic conductive glue to rupture 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 The LED chip and the pad are in 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, so that among the many metal conductive particle balls, as long as the metal conductive particle balls are turned on, the Mini / Micro LED chip can be lit normally. It is not necessary for all metal conductive particles to be turned on at the same time. The conductive performance is good, the welding difficulty is reduced, and the welding quality is improved. The insulating glue has an open time of 4 hours to 8 hours. The insulating glue can be melted by reheating, so that 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, which reduces the difficulty of maintenance and the cost of maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily described by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and the figures in the drawings do not constitute proportional limitations unless otherwise stated.

[0018] Figure 1 is a flow chart of a first embodiment of a method for manufacturing a Mini / Micro LED in an embodiment of the present invention; Figure 2 is a flow chart of a second embodiment of a method for manufacturing a Mini / Micro LED in an embodiment of the present invention; Figure 3 A partial enlarged view of an embodiment of a Mini / Micro LED in an embodiment of the present invention; Among them, 100, Mini / Micro LED; 10, substrate; 101, solder pad; 102, positive solder pad; 103, negative solder pad; 20, anisotropic conductive adhesive; 201, insulating glue layer; 202, insulating conductor; 203, insulating film; 204, metal conductive particle ball; 205, first avoidance; 206, second avoidance; 30, Mini / Micro LED chip; 301, positive pin; 302, negative pin; 303, chip body. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on another element, or there can be one or more centered elements therebetween. When an element is described as "connected" to another element, it can be directly connected to another element, or there can be one or more centered elements therebetween. The terms "vertical", "horizontal", "left", "right", "inside", "outside" and similar expressions used in this specification are only for illustrative purposes. In the description of the present invention, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating relative importance or implicitly indicating the number of technical features indicated. Therefore, unless otherwise specified, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; the meaning of "multiple" is two or more. The term "include" and any variation thereof means non-exclusive inclusion, and one or more other features, integers, steps, operations, units, components and / or combinations thereof may be present or added.

[0020] 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 a connection between two components. All technical and scientific terms used in this specification have the same meaning as those generally understood by technicians in the technical field of the present invention. The terms used in the specification 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.

[0021] 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.

[0022] For ease of understanding, the specific process of the embodiment of the present invention is described below. Figure 1A first embodiment of a method for manufacturing a Mini / Micro LED in an embodiment of the present invention includes: S1. Preparing metal conductive particle balls by mechanical separation or spraying, wherein the diameter of the metal conductive particle balls is 10 μm-20 μm; 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.

[0023] Exemplary: When the material of the metal conductive particle ball is tin powder, the specific steps of preparing the metal conductive particle ball by mechanical separation process are: heating the tin powder to above the melting point to make it liquid; using a high-speed rotating disk or a vibrating nozzle to divide the molten tin liquid into tiny droplets, and controlling the diameter of the droplets to 10μm-20μm by controlling the rotation speed and vibration frequency of the rotating disk; the liquid tin droplets form a spherical shape under the action of centrifugal force or mechanical force, and due to the effect of surface tension, the molten tin naturally tends to form a spherical shape; ensure that the liquid tin droplets are quickly cooled in air or inert gas (such as nitrogen) and solidified into tin balls with a diameter of 10μm-20μm; use a screen or particle size classification equipment to screen out tin balls that meet the required size, remove unqualified tin balls, and finally obtain tin balls with a diameter of 10μm-20μm. The principle of preparing tin balls by mechanical separation process is to form tin balls by separating molten tin metal into fine particles. This method usually involves mechanical force or vibration to control the size and distribution of liquid tin droplets.

[0024] When the material of the metal conductive particle ball is tin powder, the specific steps of preparing the metal conductive particle ball by spraying process are as follows: heating the tin powder to above the melting point to make it completely melted; the molten tin is sprayed out through the nozzle, and the tin flow is dispersed into tiny droplets by high-pressure inert gas (such as nitrogen or argon); the molten tin is introduced into a high-speed rotating disk or spray cup, and the tin liquid is thrown out by centrifugal force to form tiny tin droplets; during the spraying process, the tin droplets are quickly cooled in the air or inert gas, and due to the effect of surface tension, the tin droplets naturally form a spherical shape and solidify; the cooled tin ball is recovered by a collection device, and then the tin ball with a diameter of 10μm-20μm is separated by screening or grading equipment. The principle of preparing tin balls by spraying process is to use high-speed airflow or centrifugal force to decompose the molten tin into tiny droplets, which form tin balls during the cooling process.

[0025] S2, coating a layer of insulating coating on the surface of the metal conductive particle ball through a coating process, and air-drying to form an insulating film, wherein the thickness of the insulating film is 3%-25% of the diameter of the metal conductive particle ball; 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 - 2 m / 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.

[0026] The material of the insulating film is one or more of resin, polymer or thermoplastic polymer. For example, the resin can be epoxy resin, which has excellent mechanical strength, electrical insulation and heat resistance; the polymer can be polyimide, which has excellent heat resistance, electrical insulation and flexibility, and is suitable for high temperature process occasions; the thermoplastic polymer can be polyethylene terephthalate, polyethylene, polypropylene or ethylene-vinyl acetate copolymer, and the cost of polyethylene terephthalate is relatively low, and it has good electrical properties and mechanical strength. The insulating film made of the above materials can prevent the short circuit of the metal conductive particle ball, and make the metal conductive particle ball conduct electricity along the Z-axis direction under a specific pressure, and ensure that the conductor is protected from the influence of the external environment (such as oxidation); and it is in the position of ensuring the positioning and crimping effect of the conductor during the combination, that is, the stability during hot pressing.

[0027] 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 insulated, and the current cannot pass through, and the metal conductive particle balls cannot be turned on. If the thickness of 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 be easily broken in the Z-axis direction to expose the metal conductive particle balls, so that current can pass through the metal conductive particle balls.

[0028] For example, when the insulating film material is a material with a melting or softening temperature of about 150°C, such as polyethylene (PE), polypropylene (PP) or ethylene-vinyl acetate copolymer (EVA), during the packaging process, when the temperature rises to about 150°C, the insulating film will soften, and because the insulating film is thin, the insulating film will rupture in the Z-axis direction under the action of vertical pressure.

[0029] 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 parallel to the surface of the substrate, which are the directions in which the metal conductive particle balls need to be kept insulated, that is, the part of the insulating film that is not broken.

[0030] 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; In this step, the material of the insulating glue is modified epoxy resin, and the chemical composition of the insulating glue and the insulating film is different to prevent the insulating film from melting, and 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 been completely cured, so that the Mini / Micro LED chip can be inspected during this 4 to 8 hour period. 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 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. 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 has a shear strength of more than 20 MPa for materials such as stainless steel and has high bonding strength.

[0031] Put the metal conductive particle balls coated with insulating film into the insulating glue, and select an appropriate stirring method to stir them, so as 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 an 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 chip to be removed and replaced in a targeted manner after reheating and melting, thereby reducing the difficulty and cost of maintenance.

[0032] It is worth noting that the uniformity mentioned in this application is relative uniformity rather than absolute uniformity.

[0033] S4, providing a hydrophobic nano-steel mesh having a plurality of steel holes and a substrate having a plurality of pads, and printing the anisotropic conductive adhesive onto the pads through the hydrophobic nano-steel mesh; In this step, a substrate with a plurality of pads is provided, and steel holes are opened on the steel plate corresponding to the distribution of the pads of the substrate to form a steel mesh, and a layer of hydrophobic nano-coating is coated on the steel mesh to prevent 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 are made to correspond to the pads one by one, and 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 on the pads through the steel holes.

[0034] S5, peeling off the hydrophobic nano-steel mesh; 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, which facilitates the subsequent mounting of the Mini / Micro LED chip on the anisotropic conductive adhesive.

[0035] S6. Provide a Mini / Micro LED chip, mount the Mini / Micro LED chip on the anisotropic conductive adhesive located on the pad, and heat and pressurize the anisotropic conductive adhesive 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.

[0036] In this step, the Mini / Micro LED chip is an unpackaged Mini / Micro LED chip or a packaged Mini / Micro LED chip, and the unpackaged Mini / Micro LED chip or the packaged Mini / Micro LED chip is mounted on the anisotropic conductive adhesive 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 glue dispensing process is required, which saves process steps and reduces costs. Then, the unpackaged Mini / Micro LED chip or the packaged Mini / Micro LED chip on the anisotropic conductive adhesive is heated and pressurized. When heated to 120°C-250°C, the insulating film of the anisotropic conductive adhesive is softened. Under the action of vertical mechanical pressure, excess insulating glue overflows, and the insulating film is broken 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 The LED chip and the pad 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 initially, and a Mini / Micro LED is obtained.

[0037] In this embodiment, a metal conductive particle ball with a diameter of 10 μm-20 μm is prepared by a mechanical separation process or a spraying process, and a layer of insulating coating is coated on the surface of the metal conductive particle ball by a coating process to form an insulating film with a thickness of 3%-25% of the diameter of the metal conductive particle ball, so that the insulating film softens when heated to 120° C.-250° C. and ruptures under vertical pressure, exposing the metal conductive particles at the rupture. The metal conductive particle ball coated with the insulating film is placed in insulating glue and stirred to form an anisotropic conductive glue, and the insulating glue fixes and connects the Mini / Micro LED chip, the metal conductive particle ball and the pad to improve the electrical connection stability; the anisotropic conductive glue is printed on the pad through 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 metal conductive particle ball and the pad. The LED chip and the pad are in 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, so that among the many metal conductive particle balls, as long as the metal conductive particle balls are turned on, the Mini / Micro LED chip can be lit normally. It is not necessary for all metal conductive particles to be turned on at the same time. The conductive performance is good, the welding difficulty is reduced, and the welding quality is improved. The insulating glue has an open time of 4 hours to 8 hours. The insulating glue can be melted by reheating, so that 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, which reduces the difficulty of maintenance and the cost of maintenance.

[0038] See also Figure 2 As shown, the embodiment of the present invention also discloses a second embodiment of a method for manufacturing a Mini / Micro LED, including: 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; 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.

[0039] S11, immersing the metal conductive particle ball in a chemical solution by chemical deposition, forming an insulating coating on the surface of the metal conductive particle ball by chemical reaction, and air-drying the insulating coating to form an insulating film; or, depositing the insulating coating material on the surface of the metal conductive particle ball by physical vapor deposition to form an insulating coating, and air-drying the insulating coating to form an insulating film; 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 to reduce the metal ions in the insulating coating material and deposit them on the surface of the metal conductive particle balls to form an insulating coating with a thickness of 3%-25% of the diameter of the metal conductive particle balls, 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, and the insulating film wraps the metal conductive particle balls.

[0040] Physical vapor deposition is a method of vaporizing the coating material by physical methods (such as evaporation, sputtering, etc.) and depositing a film on the surface of the substrate. Specifically, in a vacuum environment, the insulating coating material is deposited on the surface of the metal conductive particle ball by evaporation or sputtering to form an insulating coating with a thickness of 3%-25% of the diameter of the metal conductive particle ball, 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.

[0041] 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 being short-circuited 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, multiple Mini / Micro LED chips are used as a collection, and no short circuit will occur 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 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 applied to ultra-high-resolution Mini / Micro LED display screen, of course, the diameter of the steel hole can be designed to accommodate the size of two, four, five, six welding pads, etc. This embodiment does not impose specific restrictions on the number of welding pads that the diameter of the steel hole can be designed to accommodate.

[0042] 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 a plurality of the metal conductive particle balls are evenly distributed in the insulating glue to form an anisotropic conductive glue; or, Providing an insulating glue, placing the metal conductive particle balls coated with the insulating film into the insulating glue, and stirring the metal conductive particle balls by a planetary mixer with a combined motion of rotation and revolution, so that a plurality of the metal conductive particle balls are evenly distributed in the insulating glue to form an anisotropic conductive glue; 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 and make the metal conductive particle balls wrapped with insulating film easier to disperse; the metal conductive particle balls wrapped with 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 insulating film and the generation of bubbles, which helps to evenly distribute the metal conductive particle balls wrapped with 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 insulating film and reduce agglomeration. The dispersant can be a surfactant or an organic solvent.

[0043] 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.

[0044] Since the current driving 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 even only a few tenths of a milliampere in many cases. Therefore, as long as the metal conductive particle ball can touch the pad of the Mini / Micro LED chip and the pad of the substrate, the current can be conducted and the Mini / Micro LED chip can be lit normally.

[0045] Therefore, in the case of low current demand, even if some solder balls are not fully in contact during the welding process, it will not affect the normal power-on and lighting of the chip. However, in order to ensure the stability and reliability of long-term operation, try to ensure that the multiple solder balls can contact the pads well. Therefore, due to the viscosity and consistency of the glue, the metal conductive particle balls wrapped with the insulating film have a small amount of adhesion, but this small amount of adhesion does not affect the basic working principle of the metal conductive particle balls.

[0046] The steps of S4 include: 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; S14, coating a layer of nano-hydrophobic coating on the steel mesh to obtain a hydrophobic nano-steel mesh; 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; 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.

[0047] In this step, the substrate can be one of a circuit board or a glass substrate, and the printing of 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, a perfluoroalkyl silane compound, and 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 prolongs the service life of the hydrophobic nano steel mesh; it has excellent corrosion resistance and chemical stability. The material of silane-based nano coating is octyltriethoxysilane or methyltrichlorosilane, which has good hydrophobicity and a water contact angle of up to 110°-130°, preventing anisotropic conductive adhesive from adhering to the steel holes of hydrophobic nano steel mesh; it has strong chemical bonding, stable and wear-resistant coating; it is easy to process and prepare, has excellent adhesion, and is suitable for forming a long-term and effective anti-sticking layer on the surface of the steel mesh. Nano-silicon dioxide coating has good hydrophobicity, and its performance can be enhanced by chemical modification; it has good wear resistance and thermal stability; it has low cost and is suitable for surface treatment of steel mesh produced in large quantities.

[0048] 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 visual positioning system of the printer 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 scraper in the steel screen printer (usually made of metal or polyurethane material) pushes the anisotropic conductive glue onto the surface of the hydrophobic nano steel mesh and scrapes it along the hydrophobic nano steel mesh at a set speed and pressure; the scraper moves back and forth on the surface of the hydrophobic nano steel mesh, squeezing the anisotropic conductive glue through the steel holes on the hydrophobic nano steel mesh and printing it on the pad of the substrate, so that the height of the anisotropic conductive glue on the pad is consistent, and the excess anisotropic conductive glue is collected by the scraper back to the top of the hydrophobic nano steel mesh; after the anisotropic conductive glue is filled, the control system of the steel screen printer slowly lifts the hydrophobic nano steel mesh to gradually separate the hydrophobic nano steel mesh from the substrate. Among them, the scraper speed: 20~100 mm / s, the scraper pressure: 0.5~1.5 kg, the printing environment: the humidity is less than 60%, keep it clean and dry.

[0049] S17, peeling off the hydrophobic nano-steel mesh; In this step, the description of the above step S18 refers to S5 of the first embodiment, and this step will not be repeated.

[0050] The steps of S6 include: S18, mounting the Mini / Micro LED chip onto the anisotropic conductive adhesive on the pad through a mass transfer process or a SMT process; 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, and 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.

[0051] In this step, a mass transfer process or a standard SMT process is used according to different mounting objects.

[0052] When the mounting object is an unpackaged Mini / Micro LED chip, a mass transfer process can be used. Specifically, a transfer head with an elastic mold or an electromagnetic adsorption head is used to pick up the Mini / Micro LED chips in batches from a temporary carrier; the picked Mini / Micro LED chips are accurately aligned with the anisotropic conductive adhesive on the pad through a visual recognition system; and the Mini / Micro LED chips are released onto the anisotropic conductive adhesive. Among them, the alignment accuracy is: ±1μm~2μm, the release pressure is: 0.2MPa~1.0 MPa, and the temperature is: 80°C~150°C; the mass transfer process can transfer and accurately mount the Mini / Micro LED chips from the carrier of the Mini / Micro LED chip to the anisotropic conductive adhesive on the pad in large quantities, improve mounting efficiency, save time, reduce costs, and ensure high-quality electrical connections and mechanical strength.

[0053] When the mounting object is a packaged Mini / Micro LED chip, the standard SMT process is used to mount the packaged Mini / Micro LED chip on the anisotropic conductive adhesive on the pad. Specifically, a transfer head with an elastic mold or an electromagnetic adsorption head is used, and the packaged Mini / Micro LED chip is picked up by the placement machine; the packaged Mini / Micro LED chip is accurately aligned with the anisotropic conductive adhesive on the pad through the placement machine's visual system; the packaged Mini / Micro LED chip is accurately placed on the anisotropic conductive adhesive to ensure high-quality electrical connection and mechanical strength.

[0054] 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, and then a vertical uniform pressure of 30N·m-100N·m is applied to the Mini / Micro LED chip through a flat pressure plate, so that the softened insulating film breaks in the Z-axis direction to form a first avoidance and a second avoidance. Since the insulating film wraps the metal conductive particle balls, when the insulating film breaks, the metal conductive particle balls are exposed through the first avoidance and the second avoidance, and the exposed metal conductive particle balls are respectively connected to the Mini / Micro The LED chip and the pad are in contact to form a vertical conductive path. Since the insulating film is not broken in the X-axis and Y-axis directions, and after the insulating film is cured, it is prevented from being damaged by external force or environmental influences during use, and the short circuit caused by the contact of 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, the metal conductive particle ball and the pad are in closer contact, thereby improving the stability of the electrical connection.

[0055] A Mini / Micro LED chip is soldered on a pad, and the current driving 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 even only a few tenths of a milliampere in many cases. The current required to drive a single Mini / Micro LED chip is very small, and there are multiple metal conductive particle balls in the anisotropic conductive glue on a pad, and a Mini / Micro LED chip is soldered on 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 the metal conductive particles to be conductive at the same time, which reduces the difficulty of welding and improves the welding quality.

[0056] S20, testing the Mini / Micro LED chip; 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.

[0057] S21. When the Mini / Micro LED chip is a defective product, 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.

[0058] In this step, when the Mini / Micro LED chip is detected to be defective, the anisotropic conductive glue can be reactivated by heating 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, the 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, which reduces the difficulty of maintenance, ensures that the product yield is close to 100%, avoids scrapping the entire substrate or display module, and has low maintenance costs. The insulating glue has an open time of 4 to 8 hours, so that defective Mini / Micro LED chips can be repaired by heating during the open time, ensuring that the product yield is close to 100% and avoiding the scrapping of the entire substrate or display module; if the problem is discovered after curing, the entire substrate or display module may be scrapped, and repair within the open time greatly reduces production waste and material loss; it enables the production line to flexibly handle quality inspection and repair, reducing the risk of batch scrapping.

[0059] The open time of the insulating glue can also be adjusted by adding specific chemical materials to the insulating glue; illustratively, the material that prolongs 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 moisture-curing glue so that the insulating glue gradually cures by absorbing moisture (humidity) in the air.

[0060] Among them, the Mini / Micro LED chip can be a blue light Mini / Micro LED chip, a green light Mini / Micro LED chip and a red light Mini / Micro LED chip. The maximum junction temperature of the blue light Mini / Micro LED chip and the green light Mini / Micro LED chip is 150°C. At this temperature, even if the heating is continued for 30 minutes, it will not have a significant impact on the lifespan of the blue light Mini / Micro LED chip and the green light Mini / Micro LED chip; the maximum junction temperature of the red light Mini / Micro LED chip is 125°C. Laboratory tests show that hot pressing at 150°C for 30 minutes will not significantly affect the lifespan of the red light Mini / Micro LED chip; 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, and the Mini / Micro LED chip; however, when the heating temperature exceeds 250°C and the heating time exceeds 10 seconds, the Mini / Micro LED chip may be damaged.

[0061] In this embodiment, a metal conductive particle ball with a diameter of 10 μm-20 μm is prepared by a mechanical separation process or a spraying process, and a layer of insulating coating is coated on the surface of the metal conductive particle ball by a coating process to form an insulating film with a thickness of 3%-25% of the diameter of the metal conductive particle ball, so that the insulating film softens when heated to 120° C.-250° C. and ruptures under vertical pressure, exposing the metal conductive particles at the rupture. The metal conductive particle ball coated with the insulating film is placed in insulating glue and stirred to form an anisotropic conductive glue, and the insulating glue fixes and connects the Mini / Micro LED chip, the metal conductive particle ball and the pad to improve the electrical connection stability; the anisotropic conductive glue is printed on the pad through 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 metal conductive particle ball and the pad. The LED chip and the pad are in 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, so that among the numerous metal conductive particle balls, as long as one metal conductive particle ball is turned on, the Mini / Micro LED chip can be lit normally, and there is no need for all metal conductive particles to be turned on 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. The insulating glue can be melted by reheating, so that 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] like Figure 3 As shown, a Mini / Micro LED is also disclosed in an embodiment of the present invention. The Mini / Micro LED is made by the manufacturing method of any of the above embodiments. The manufacturing method of any of the above embodiments can make 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 chip 30 is electrically connected to the substrate 10 through the anisotropic conductive adhesive 20.

[0063] The substrate 10 may be a circuit board or a glass substrate 10 . A plurality of pads 101 are disposed on the substrate 10 , wherein the pads 101 include a positive electrode pad 102 and a negative electrode pad 103 .

[0064] 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, and each anisotropic conductive adhesive 20 includes an insulating glue layer 201 and a plurality of insulating conductors 202, and the insulating glue layer 201 is respectively connected to the substrate 10 and the Mini / Micro LED chip 30, and the plurality of insulating conductors 202 are all provided in the insulating glue layer 201, and the insulating glue layer 201 is respectively fixedly connected to the substrate 10 and the Mini / Micro LED chip 30, 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 realizes 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.

[0065] The Mini / Micro LED chip 30 may be an unpackaged Mini / Micro LED chip 30 or a packaged Mini / Micro LED chip 30; a plurality of Mini / Micro LED chips 30 are arranged corresponding to a plurality of anisotropic conductive adhesives 20, each Mini / Micro LED chip 30 is arranged on each anisotropic conductive adhesive 20, and the other end of the insulating conductor 202 is electrically connected to the Mini / Micro LED chip 30 through the third avoidance opening. Since a plurality of insulating conductors 202 are arranged in an anisotropic conductive adhesive 20, only one or two insulating conductors 202 are electrically connected to the Mini / Micro LED chip 30 and the pad 101, so that the Mini / Micro LED chip 30 can be normally lit, the conductivity is stable, and all the metal conductive particles do not need to be turned on at the same time, which reduces the difficulty of welding and stabilizes the welding quality. Of course, the more metal conductive particles are turned on, the more stable the conductive performance is, and the longer the service life is.

[0066] 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.

[0067] Specifically, the material of the metal conductive particle ball 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 ball 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 material of the insulating film 203 is different from the chemical composition 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 opening 205 and a second avoidance opening 206, so that the Mini / Micro LED100 can be turned on in the Z-axis direction, and the insulation in the X-axis and Y-axis directions can achieve permanent insulation to avoid short circuit.

[0068] Further, the pad 101 includes a positive pad 102 and a negative pad 103, 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, 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 opening 205, and the positive pad 102 is electrically connected to the metal conductive particle ball 204 through the second avoidance opening 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 opening 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, so 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 even only a few tenths of a milliampere in many cases. 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.

[0069] 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 may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the above embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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; A layer of insulating coating is applied on the surface of the metal conductive particle ball by a coating process, and air-dried to form an insulating film, wherein the thickness of the insulating film is 3%-25% of the diameter of the metal conductive particle ball; 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 holes and a substrate having a plurality of pads, and printing the anisotropic conductive glue onto the pads through the hydrophobic nano-steel mesh; peeling off the hydrophobic nano-steel mesh; A Mini / Micro LED chip is provided, and the Mini / Micro LED chip is mounted on the anisotropic conductive adhesive located on the pad, and heating and pressurizing are performed 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 respectively in contact with the Mini / Micro LED chip and the pad to form a vertical conductive path, and the insulating glue of the anisotropic conductive adhesive is initially cured to obtain a Mini / Micro LED.

2. The manufacturing method according to claim 1, characterized in that: The material of the insulating film is one or more of resin, polymer or thermoplastic polymer; and / or the material of the insulating glue is modified epoxy resin.

3. The manufacturing method according to claim 1, characterized in that: The material of the metal conductive particle ball 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: After providing the Mini / Micro LED chip, mounting the Mini / Micro LED chip on the anisotropic conductive adhesive on the pad, heating and pressurizing the anisotropic conductive adhesive 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 respectively in contact with the Mini / Micro LED chip and the pad to form a vertical conductive path, and the insulating glue of the anisotropic conductive adhesive is initially cured to obtain the Mini / Micro LED, the method further includes: Testing the Mini / Micro LED chip; 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.

5. The manufacturing method according to claim 1, characterized in that: The step of providing a Mini / Micro LED chip, mounting the Mini / Micro LED chip on the anisotropic conductive adhesive on the pad, heating and pressurizing the anisotropic conductive adhesive 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 respectively in contact with the Mini / Micro LED chip and the pad to form a vertical conductive path, and preliminarily solidifying the insulating glue of the anisotropic conductive adhesive to obtain the Mini / Micro LED is 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 located 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, and 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.

6. The manufacturing method according to claim 1, characterized in that: 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 comprises: 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.

7. The manufacturing method according to claim 1, characterized in that: 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 comprises: The material of the insulating coating 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.

8. 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 to form an anisotropic conductive glue include: An insulating glue is provided, and metal conductive particle balls coated with the insulating film are placed in the insulating glue, and a plurality of the metal conductive particle balls are evenly distributed in the insulating glue by low-speed stirring to form an anisotropic conductive glue; or, an insulating glue is provided, and metal conductive particle balls coated with the insulating film are placed in the insulating glue, and a combination of rotation and revolution of a planetary mixer is used to stir the metal conductive particle balls so that a plurality of the metal conductive particle balls are evenly distributed in the insulating glue to form an anisotropic conductive glue.

9. 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: 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; A layer of nano hydrophobic coating is coated on the steel mesh to obtain a hydrophobic nano steel mesh.

10. A Mini / Micro LED, characterized in that: The Mini / Micro LED is manufactured using the manufacturing method described in any one of claims 1 to 9.

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