Micro-led chip and integration method therefor

Abstract

The present application relates to an integration method for a Micro-LED chip. The method comprises the steps of: forming a bonding pad on an auxiliary film by means of a laser 3D forming method; forming, on the bonding pad, a circuit pattern in communication with the bonding pad; removing the auxiliary film, and performing a double-sided immersion gold treatment on the bonding pad; and connecting the circuit pattern to a Micro-LED chip by means of the bonding pad. According to the Micro-LED chip and the integration method therefor provided in the present application, a bonding pad is formed by means of an auxiliary film and a laser 3D forming method, a circuit pattern is then formed on the bonding pad, and the bonding pad is used to form a connection between a chip and the circuit pattern, improving the manufacturing precision and efficiency of the Micro-LED chip, and thus improving the product stability of the Micro-LED chip.

Description

A Micro-LED chip and its integration method

[0001] Related applications

[0002] This application claims priority to Chinese patent application number 202311159970.1, filed on September 11, 2023, entitled “A micro-led chip and its integration method,” the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the technical field of chip preparation technology, and in particular to a Micro-LED chip and an integration method thereof. Background Art

[0004] With the advancement of liquid crystal display (LCD) screen backlight technology, the display effect brought by traditional light emitting diode (LED) backlight can no longer meet consumers' demand for higher display effects. For this reason, Micro-LED (micro light emitting diode) technology came into being.

[0005] Micro-LED display technology uses self-luminous micron-sized LEDs as pixel units, assembling them onto a driver panel to form a high-density LED array. Due to their small chip size, high integration, and self-luminescence, Micro-LEDs offer significant advantages over LCDs and organic light-emitting diodes (OLEDs) in terms of brightness, resolution, contrast, energy consumption, lifespan, response speed, and thermal stability.

[0006] Micro-LED products utilize thin-film, miniaturized, and arrayed LED structures, reducing their size to approximately 1μm to 10μm. These LEDs are then transferred to substrates in batches and packaged to create a micro-diode display. As micro-LED electronic products become increasingly miniaturized and multifunctional, the integration of printed circuit boards (PCBs) within these products is required to increase. Consequently, the circuit patterns on these PCBs are becoming increasingly complex, requiring more and more circuits to be processed within a given PCB area.

[0007] Currently, the production process for Micro-LED PCBs typically involves first coating the substrate with a copper layer, then etching the copper layer to form the desired circuit pattern. During etching, the etching solution not only corrodes the copper layer vertically but also laterally. As circuit patterns become increasingly complex, the spacing between adjacent circuits decreases. This lateral corrosion of the copper layer by the etching solution can result in excessively narrow circuit widths, increasing the PCB's defect rate. Therefore, new circuit connectivity methods are needed to integrate Micro-LED chips.

[0008] Summary of the Invention

[0009] The present application aims to at least partially address one of the problems in the related art. To this end, the present application provides a Micro-LED chip and its integration method, which utilizes an auxiliary film and a laser 3D forming method to form a solder pad, then forms a circuit pattern on the solder pad, and uses the solder pad to form a connection between the chip and the circuit pattern, thereby improving the manufacturing accuracy and efficiency of the Micro-LED chip and enhancing the product stability of the Micro-LED chip.

[0010] To achieve the above objectives, the present application adopts the following technical solution: A method for integrating Micro-LED chips, comprising the following steps:

[0011] forming a pad on the auxiliary film by a laser 3D forming method;

[0012] forming a circuit pattern on the pad that is in communication with the pad;

[0013] Remove the auxiliary film and perform double-sided gold immersion on the pads; and connect the circuit pattern to the Micro-LED chip through the pads.

[0014] Furthermore, the laser 3D forming method includes: sequentially defining pad areas on the auxiliary film, melting copper slurry using a laser, and allowing the molten copper slurry to drip onto the pad area drop by drop and solidify to form a pad.

[0015] Furthermore, the pad formed by solidifying and accumulating the copper paste is laser polished to form a cylindrical pad.

[0016] Furthermore, before forming the pad on the auxiliary film, the method further includes: performing a roughening treatment on the auxiliary film, wherein the roughening treatment includes plasma etching or liquid etching.

[0017] Furthermore, forming a circuit pattern connected to the pad on the pad specifically includes:

[0018] Coating hot melt adhesive on one side of the auxiliary film where the solder pad is provided, wherein the thickness of the hot melt adhesive is greater than the height of the solder pad;

[0019] Grind the board to remove the hot melt glue on the pad;

[0020] depositing an initial copper layer;

[0021] Applying a dry film on the initial copper layer, exposing and developing it to form a dry film;

[0022] Horizontal electroplating forms a circuit pattern of 7 to 8 microns;

[0023] The dry film is removed by stripping, and the initial copper layer covered by the dry film is removed by flash etching.

[0024] Furthermore, grinding the plate to remove the hot melt adhesive on the pad includes: first using a ceramic brush to grind the plate from the top of the hot melt adhesive, and then using a laser cleaning method to remove the hot melt adhesive on the pad.

[0025] Furthermore, applying the hot melt adhesive specifically includes: melting the hot melt adhesive at high temperature in a vacuum box, applying the hot melt adhesive by silk screen printing, and leveling the hot melt adhesive applied on the surface of the pad and the auxiliary film.

[0026] Further, the auxiliary film is removed, and gold is applied to the pads and circuit patterns, including:

[0027] Remove auxiliary membrane;

[0028] Apply hot melt adhesive on the surface of the pad and circuit pattern;

[0029] Laser cleaning to expose the pads on the side where the circuit pattern is located;

[0030] Perform immersion gold treatment on both ends of the pad.

[0031] Furthermore, before coating the hot melt adhesive on the soldering pad and the circuit pattern surface, the method further includes: plasma cleaning of the soldering pad; and automatic optical detection.

[0032] Furthermore, a method for integrating a Micro-LED chip includes the following steps:

[0033] Forming pads on the auxiliary film by a laser 3D forming method; the laser 3D forming method includes: sequentially defining pad areas on the auxiliary film, using a laser to melt copper slurry, so that the molten copper slurry drips dropwise onto the pad area and solidifies to form the pad;

[0034] A circuit pattern connected to the pad is formed on the pad; specifically, the process includes: applying hot melt adhesive on one side of the auxiliary film where the pad is provided, wherein the thickness of the hot melt adhesive is greater than the height of the pad; removing the hot melt adhesive on the pad by grinding the plate; depositing an initial copper layer; applying a dry film on the initial copper layer, exposing and developing the dry film; forming a circuit pattern with a thickness of 7 to 8 microns by horizontal electroplating; removing the dry film by stripping the film, and removing the initial copper layer covered by the dry film by flash etching;

[0035] Remove the auxiliary film and apply hot melt adhesive on the surface of the pad and circuit pattern;

[0036] Laser cleaning to expose the pads on the side where the circuit pattern is located;

[0037] Perform gold plating on both ends of the pads; and connect the circuit pattern to the Micro-LED chip through the pads.

[0038] A Micro-LED chip is prepared based on the above-mentioned Micro-LED chip integration method.

[0039] Furthermore, a Micro-LED chip is prepared using a Micro-LED chip integration method; the Micro-LED chip integration method includes the following steps:

[0040] forming a pad on the auxiliary film by a laser 3D forming method;

[0041] forming a circuit pattern on the pad that is in communication with the pad;

[0042] Remove the auxiliary film and perform double-sided gold immersion on the pads; and connect the circuit pattern to the Micro-LED chip through the pads.

[0043] Furthermore, for the Micro-LED chip, the laser 3D forming method includes: sequentially defining pad areas on the auxiliary film, using a laser to melt copper slurry, so that the molten copper slurry drips dropwise onto the pad area and solidifies to form a pad.

[0044] Furthermore, for the Micro-LED chip, the pad formed by the solidification and accumulation of the copper paste is laser polished to form a cylindrical pad.

[0045] Furthermore, for the Micro-LED chip, before forming the solder pad on the auxiliary film, the method further includes: performing a roughening treatment on the auxiliary film, wherein the roughening treatment includes plasma etching or liquid etching.

[0046] Furthermore, for the aforementioned Micro-LED chip, forming a circuit pattern connected to the solder pad on the solder pad specifically includes:

[0047] Coating hot melt adhesive on one side of the auxiliary film where the solder pad is provided, wherein the thickness of the hot melt adhesive is greater than the height of the solder pad;

[0048] Grind the board to remove the hot melt glue on the pad;

[0049] depositing an initial copper layer;

[0050] Applying dry film on the initial copper layer, exposing and developing the dry film;

[0051] Horizontal electroplating forms a circuit pattern of 7 to 8 microns;

[0052] The dry film is removed by stripping, and the initial copper layer covered by the dry film is removed by flash etching.

[0053] Furthermore, for the Micro-LED chip, grinding the plate to remove the hot melt adhesive on the pad includes: first using a ceramic brush to grind the plate from the top of the hot melt adhesive, and then using a laser cleaning method to remove the hot melt adhesive on the pad.

[0054] Furthermore, for the Micro-LED chip, coating the hot melt adhesive specifically includes: melting the hot melt adhesive at high temperature in a vacuum box, coating the hot melt adhesive by silk screen printing, and leveling the hot melt adhesive coated on the surface of the solder pad and the auxiliary film.

[0055] Furthermore, for the aforementioned Micro-LED chip, removing the auxiliary film and applying gold to the pads and circuit patterns include:

[0056] Remove auxiliary membrane;

[0057] Apply hot melt adhesive on the surface of the pad and circuit pattern;

[0058] Laser cleaning to expose the pads on the side where the circuit pattern is located;

[0059] Perform immersion gold treatment on both ends of the pad.

[0060] Furthermore, for the Micro-LED chip, before applying hot melt adhesive on the solder pad and circuit pattern surface, the process also includes: plasma cleaning of the solder pad; and automatic optical inspection.

[0061] Furthermore, for the aforementioned Micro-LED chip, the integration method of the Micro-LED chip includes the following steps:

[0062] Forming pads on the auxiliary film by a laser 3D forming method; the laser 3D forming method includes: sequentially defining pad areas on the auxiliary film, using a laser to melt copper slurry, so that the molten copper slurry drips dropwise onto the pad area and solidifies to form the pad;

[0063] A circuit pattern connected to the pad is formed on the pad; specifically, the process includes: applying hot melt adhesive on one side of the auxiliary film where the pad is provided, wherein the thickness of the hot melt adhesive is greater than the height of the pad; removing the hot melt adhesive on the pad by grinding the plate; depositing an initial copper layer; applying a dry film on the initial copper layer, exposing and developing the dry film; forming a circuit pattern with a thickness of 7 to 8 microns by horizontal electroplating; removing the dry film by stripping the film, and removing the initial copper layer covered by the dry film by flash etching;

[0064] Remove the auxiliary film and apply hot melt adhesive on the surface of the pad and circuit pattern;

[0065] Laser cleaning to expose the pads on the side where the circuit pattern is located;

[0066] Perform gold plating on both ends of the pads; and connect the circuit pattern to the Micro-LED chip through the pads.

[0067] The above-mentioned technical solution provided by the embodiment of the present application has the following advantages compared with the existing technology: the present application forms a soldering pad on an auxiliary film by a laser 3D forming method; forms a circuit pattern connected to the soldering pad on the soldering pad; removes the auxiliary film and performs double-sided gold immersion treatment on the soldering pad; and connects the circuit pattern to the Micro-LED chip through the soldering pad; the laser 3D forming method is used to form the soldering pad, which can ensure the accuracy of the soldering pad position, shape and size, and connects the circuit pattern and the Micro-LED chip through the soldering pad, avoiding the tedious operation of wire connection or wiring connection, and improving the electrical connection accuracy between the Micro-LED chip and the circuit pattern; the present application forms the soldering pad with the help of an auxiliary film, and forms a circuit pattern on the soldering pad, and then uses the soldering pad to connect the circuit pattern and the Micro-LED chip, thereby improving the preparation efficiency and connection accuracy of the outer circuit of the Micro-LED chip, being suitable for the preparation and connection of small-size soldering pads, improving the production accuracy and efficiency of the Micro-LED chip, and improving the product stability of the Micro-LED chip.

[0068] The Micro-LED chip prepared using the method of this application can ensure the precise positioning of the pads, efficient and high-precision circuit preparation, and good product yield and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0070] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0071] In the attached figure:

[0072] FIG1 is a flow chart of the preparation method in Example 3. DETAILED DESCRIPTION

[0073] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0074] In order to have a clearer understanding of the technical features, purposes and effects of the present application, the specific embodiments of the present application are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings and are constructed and operated in specific directions. They are only for the convenience of describing the technical solution and do not indicate that the mechanisms or components referred to must have specific directions. Therefore, they should not be understood as limitations on the present application.

[0075] It should also be noted that, unless otherwise clearly specified and limited, terms such as "installed", "connected", "connected", "fixed", and "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intervening elements. The terms "first", "second", and "third" are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", and "third" can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0076] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, mechanisms, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0077] Example 1

[0078] The present application provides a method for integrating a Micro-LED chip, characterized by comprising the following steps:

[0079] forming a pad on the auxiliary film by a laser 3D forming method;

[0080] forming a circuit pattern on the pad that is in communication with the pad;

[0081] Remove the auxiliary film and perform double-sided immersion gold treatment on the pads; and connect the circuit pattern to the Micro-LED chip through the pads.

[0082] This application uses a laser 3D forming method to form the pad, which can ensure the accuracy of the pad position, shape and size. The circuit pattern and the Micro-LED chip are connected by the pad, avoiding the tedious operation of wire connection or wiring connection, and improving the electrical connection accuracy between the Micro-LED chip and the circuit pattern; this application uses an auxiliary film to form the pad, and forms a circuit pattern on the pad, and then uses the pad to connect the circuit pattern and the Micro-LED chip, thereby improving the preparation efficiency and connection accuracy of the outer circuit of the Micro-LED chip. It is suitable for the preparation and connection of small-size pads, improves the production accuracy and efficiency of the Micro-LED chip, and thus improves the product stability of the Micro-LED chip.

[0083] The Micro-LED chip prepared using the method of this application can ensure the precise positioning of the pads, efficient and high-precision circuit preparation, and good product yield and stability.

[0084] Example 2

[0085] This embodiment provides a method for integrating a Micro-LED chip, including the following steps:

[0086] S1: Forming pads on the auxiliary film by laser 3D forming method. Specifically including:

[0087] S11: performing a roughening process on the auxiliary film, wherein the roughening process includes plasma etching or liquid etching. The auxiliary film after the roughening process has a certain roughness, which is convenient for the subsequent formation of the pad.

[0088] S12: Define the pad areas on the auxiliary film in sequence, and use a laser to melt the copper slurry so that the molten copper slurry drips onto the pad area and solidifies to form a pad. Since the pads in the Micro-LED chip are relatively dense, the pad areas can be defined one by one on the auxiliary film in advance, and each pad area will subsequently form a pad. During the laser 3D forming process, the pads are formed by the droplet accumulation of molten copper slurry, and copper pillars can be precisely formed at the pre-defined pad positions.

[0089] S13: Laser polishing the pad formed by the solidified copper slurry to form a cylindrical pad. The pad formed by the droplet-by-drop copper slurry has an irregular shape and can be polished to form a cylindrical pad. Laser polishing refers to controlling the laser power to cut or melt the irregular pad so that it has a cylindrical shape.

[0090] This application uses a laser 3D forming method to form the pad, which can ensure the accuracy of the pad position, shape and size. The circuit pattern and the Micro-LED chip are connected through the pad, avoiding the tedious operations of wire connection or wiring connection, and improving the electrical connection accuracy between the Micro-LED chip and the circuit pattern.

[0091] S2: forming a circuit pattern connected to the pad on the pad. Since the previous step is to form the pad on the auxiliary film by laser 3D forming, this step can also be understood as forming a circuit pattern connected to the pad on the auxiliary film. Specifically including:

[0092] S21: Apply hot melt adhesive to the side of the auxiliary film where the pad is located, with the thickness of the hot melt adhesive being greater than the height of the pad. Specific method: melt the hot melt adhesive at high temperature in a vacuum chamber, apply the hot melt adhesive by silk screen printing, and level the hot melt adhesive applied to the pad and the auxiliary film surface.

[0093] The hot melt adhesive in this step is also used as a solder resist dielectric layer and an insulating layer. It is applied by silk screen printing. The coating method is simple and quick. At the same time, the hot melt adhesive has good insulating layer and solder resist properties. It is easy to remove after the circuit pattern is formed, thereby improving the efficiency of forming the circuit pattern.

[0094] S22: Grind the board to remove the hot melt adhesive on the pad; specifically includes the following two steps:

[0095] S221: First, use a ceramic brush to grind the plate from the top of the hot melt adhesive; the grinding speed at this time is relatively fast, which can be understood as a rapid rough grinding stage to quickly remove excess hot melt adhesive.

[0096] S222: Laser cleaning is then used to remove the hot melt adhesive from the pads. When the rapid rough grinding of the board reaches a position close to the pads, laser cleaning can be used to remove the hot melt adhesive above the pads to avoid scratching the pads. Excess hot melt adhesive on the pads can be removed by laser melting or laser cutting. Laser cleaning also requires even removal of the hot melt adhesive, ensuring that the surface is flush and free of the pads, facilitating subsequent deposition of circuit patterns.

[0097] S23: Deposit the initial copper layer. This initial copper layer is relatively thin, typically less than 1 micron. Chemical sputtering or other chemical copper deposition methods can be used to deposit a thin initial copper layer on the pads and hot melt adhesive. The purpose of this initial copper layer is to provide a baseline for subsequent horizontal electroplating, so it only needs to be relatively thin.

[0098] S24: Apply dry film on the initial copper layer, expose and develop the dry film. Apply dry film globally on the initial copper layer, and then remove the dry film outside the circuit pattern area through exposure and development. At this time, the pattern outside the area covered by the dry film is the subsequent circuit pattern. In other words, the area that does not require horizontal electroplating is covered by the dry film, and the exposed part is the position of the circuit pattern. It should be noted that: the initial copper layer in this application is globally deposited, that is, it is globally deposited on the soldering pad and the hot melt adhesive at the same time; the area outside the dry film after applying the dry film, exposing and developing is the graphic area, and part of the graphic area is located above the soldering pad and part is located above the hot melt adhesive.

[0099] S25: Horizontal electroplating forms a 7- to 8-micron circuit pattern. During the horizontal electroplating process, an initial copper layer exists in the areas not covered by the dry film, which facilitates horizontal electroplating. No copper layer is deposited in areas covered by the dry film.

[0100] S26: The dry film after development is removed by stripping and flash etching. At this time, a pad is formed on the auxiliary film, and a circuit pattern is formed on the side of the pad away from the auxiliary film.

[0101] S3: Remove the auxiliary film and perform double-sided immersion gold on the pad. Specifically include:

[0102] S31: removing the auxiliary film; in the present application, the auxiliary film may be a PET film, and the auxiliary film is removed by liquid phase etching.

[0103] S32: plasma cleaning the pad; after removing the auxiliary film, in order to avoid residual auxiliary film at the bottom of the pad, plasma gas is used to etch the bottom of the pad, that is, the end where the pad and the auxiliary film abut, to ensure that there is no residual auxiliary film material on the pad.

[0104] S33: Automated Optical Inspection (AOI): Perform AOI inspection on the pad and the circuit pattern formed on the top of the pad to inspect the appearance and status of the circuit pattern.

[0105] S34: applying hot melt adhesive to the surface of the pads and the circuit pattern; the hot melt adhesive in this step also serves as a solder resist dielectric layer and an insulating layer. The hot melt adhesive at this time covers the circuit pattern and the pads on one side of the circuit pattern.

[0106] S35: Laser cleaning exposes the pads on the side close to the circuit pattern. The ends of the pads away from the circuit pattern have been exposed. At this time, laser cleaning refers to cleaning the end of the pad close to the circuit pattern, so that both ends of the pad are exposed and the other areas are covered with hot melt adhesive.

[0107] S36: Double-sided immersion gold treatment is performed on the pads. Both ends of the exposed pads are immersed in gold at the same time to increase their conductive connectivity and the thickness of the pads.

[0108] During the gold deposition process, an extremely thin layer of oxide can be formed on the metal surface. This layer of oxide can effectively prevent metal corrosion, thereby improving the corrosion resistance of the pads and circuit patterns.

[0109] S4: Connect the circuit pattern to the Micro-LED chip through the soldering pad, solder the soldering pad after gold immersion to the corresponding interconnection layer of the Micro-LED chip, and realize the electrical connection between the interconnection layer or soldering pad in the Micro-LED chip and the outer circuit pattern through the soldering pad formed by the laser 3D molding method.

[0110] This application uses an auxiliary film to form a solder pad, forms a circuit pattern on the solder pad, and then uses the solder pad to connect the circuit pattern and the Micro-LED chip, thereby improving the preparation efficiency and connection accuracy of the outer circuit of the Micro-LED chip. It is suitable for the preparation and connection of small-size solder pads, improves the production accuracy and efficiency of the Micro-LED chip, and improves the product stability of the Micro-LED chip.

[0111] Example 3

[0112] As shown in FIG1 , this embodiment provides a method for integrating a Micro-LED chip, including the following steps:

[0113] PET film roughening: Roughening treatment includes plasma etching or chemical etching. The PET film after roughening has a certain roughness, which is convenient for the subsequent formation of solder pads.

[0114] Laser 3D forming pads: The pad areas are defined on the PET film in sequence, and the laser is used to melt the copper paste so that the molten copper paste drips onto the pad area and solidifies to form a pad. The pads used in Micro-LED chips are relatively dense, and the pad areas can be defined one by one on the PET film in advance, and each pad area will be formed into a pad later. During the laser 3D forming process, the pads are formed by the drop-by-drop accumulation of molten copper paste, and copper columns can be precisely formed at the pre-defined pad positions. The pads formed by the solidified accumulation of copper paste are laser polished to form cylindrical pads. The pads accumulated drop by drop of copper paste have irregular shapes, and laser polishing can be used to form cylindrical pads. Laser polishing refers to controlling the laser power to cut or melt the irregular pads so that their final shape is cylindrical.

[0115] This application uses a laser 3D forming method to form the pad, which can ensure the accuracy of the pad position, shape and size. The circuit pattern and the Micro-LED chip are connected through the pad, avoiding the tedious operations of wire connection or wiring connection, and improving the electrical connection accuracy between the Micro-LED chip and the circuit pattern.

[0116] Apply hot melt adhesive: Apply hot melt adhesive to the side of the PET film where the pad is located, with the thickness of the hot melt adhesive greater than the height of the pad. Specific method: Melt the hot melt adhesive at high temperature in a vacuum chamber, apply the hot melt adhesive using a silk screen method, and smooth the hot melt adhesive applied to the pad and PET film surface.

[0117] The hot melt adhesive in this step is also used as a solder resist dielectric layer and an insulating layer. It is applied by silk screen printing. The coating method is simple and quick. At the same time, the hot melt adhesive has good insulating layer and solder resist properties. It is easy to remove after the circuit pattern is formed, thereby improving the efficiency of forming the circuit pattern.

[0118] Ceramic grinding plate: Use a ceramic brush to grind the plate from the top of the hot melt adhesive; the grinding speed at this time is faster, which can be understood as a rapid coarse grinding stage to quickly remove excess hot melt adhesive.

[0119] Laser cleaning: Laser cleaning is used to remove hot melt adhesive from pads. When the board is rapidly roughed down close to the pad, laser cleaning can be used to remove the hot melt adhesive above the pad to avoid scratching the pad. Excess hot melt adhesive can be removed by laser melting or laser cutting. Laser cleaning also requires even removal of the hot melt adhesive, ensuring a flush surface and clearing the pad to facilitate subsequent circuit pattern deposition.

[0120] Sputtering the initial copper layer: The initial copper layer is relatively thin. Chemical sputtering or other chemical copper deposition methods can be used to deposit a thin initial copper layer on the pad and hot melt adhesive. The purpose of the initial copper layer is to provide a benchmark for subsequent horizontal electroplating, so it only needs to be thin.

[0121] Dry film application, exposure, and development: Dry film is applied globally on the initial copper layer, and then the dry film outside the circuit pattern area is removed through exposure and development. At this time, the pattern outside the dry film-covered area is the subsequent circuit pattern. In other words, the area that does not require horizontal electroplating is covered by the dry film, and the exposed part is the location of the circuit pattern. It should be noted that: in this application, the initial copper layer is deposited globally, that is, it is deposited globally on the pad and hot melt adhesive at the same time; the area outside the dry film after dry film application, exposure, and development is the pattern area, and the pattern area is partially located above the pad and partially located above the hot melt adhesive.

[0122] Horizontal plating: Horizontal plating forms a 7- to 8-micron circuit pattern. During the horizontal plating process, an initial copper layer forms in areas not covered by the dry film, facilitating horizontal plating. No copper is deposited in areas covered by the dry film.

[0123] Stripping and flash etching: Stripping and flash etching removes the dry film after development. At this point, pads are formed on the auxiliary film, and the circuit pattern is formed on the side of the pad away from the auxiliary film.

[0124] Remove the PET film; in this application, the auxiliary film can be a PET film, and the PET film is removed by liquid phase etching.

[0125] Plasma cleaning of the pad; after removing the PET film, in order to avoid residual PET film at the bottom of the pad, plasma gas is used to etch the bottom of the pad, that is, the end where the pad abuts the PET film, to ensure that there is no residual PET film on the pad.

[0126] AOI inspection: Perform AOI inspection on the pad and the circuit pattern formed on its top to detect the appearance and status of the circuit pattern.

[0127] Apply hot melt adhesive; the hot melt adhesive in this step also serves as a solder resist dielectric layer and an insulating layer. The hot melt adhesive at this time covers the circuit pattern and the pad on one side of the circuit pattern.

[0128] Laser cleaning: Expose the pads on the side close to the circuit pattern. The ends of the pads on the side away from the circuit pattern have been exposed. In this case, laser cleaning refers to cleaning the end of the pad close to the circuit pattern, so that both ends of the pad are exposed, and the rest of the area is covered with hot melt adhesive.

[0129] Double-sided immersion gold treatment: immersion gold is applied to both ends of the exposed pad simultaneously to increase its conductive connectivity and thickness. During the immersion gold process, a very thin layer of oxide can form on the metal surface. This oxide layer can effectively prevent metal corrosion, thereby improving the corrosion resistance of the pad and circuit pattern.

[0130] Molding: The pads and circuit patterns formed above are milled to facilitate subsequent packaging.

[0131] Inspection and warehousing.

[0132] This application uses PET film to form a solder pad, forms a circuit pattern on the solder pad, and then uses the solder pad to connect the circuit pattern and the Micro-LED chip, thereby improving the preparation efficiency and connection accuracy of the outer circuit of the Micro-LED chip. It is suitable for the preparation and connection of small-size solder pads, improves the production accuracy and efficiency of the Micro-LED chip, and thus improves the product stability of the Micro-LED chip.

[0133] This application also provides a Micro-LED chip manufactured using the above method. This application provides a new solder pad formation process and a method for achieving connectivity between the Micro-LED chip and the outer circuit through the solder pad, which improves the efficiency of circuit formation and connection, ensures the accuracy of circuit connection, and improves the product stability of the Micro-LED chip.

[0134] Furthermore, a Micro-LED chip is prepared using a Micro-LED chip integration method; the Micro-LED chip integration method includes the following steps: forming a soldering pad on an auxiliary film using a laser 3D molding method; forming a circuit pattern connected to the soldering pad on the soldering pad; removing the auxiliary film and performing double-sided gold deposition on the soldering pad; and connecting the circuit pattern to the Micro-LED chip through the soldering pad.

[0135] Furthermore, for the Micro-LED chip, the laser 3D forming method includes: sequentially defining pad areas on the auxiliary film, using a laser to melt copper slurry, so that the molten copper slurry drips dropwise onto the pad area and solidifies to form a pad.

[0136] Furthermore, for the Micro-LED chip, the pad formed by the solidification and accumulation of the copper paste is laser polished to form a cylindrical pad.

[0137] Furthermore, for the Micro-LED chip, before forming the solder pad on the auxiliary film, the method further includes: performing a roughening treatment on the auxiliary film, wherein the roughening treatment includes plasma etching or liquid etching.

[0138] Furthermore, for the described Micro-LED chip, a circuit pattern connected to the pad is formed on the pad, specifically including: coating hot melt adhesive on one side of the auxiliary film where the pad is provided, and the thickness of the hot melt adhesive is greater than the height of the pad; grinding the plate to remove the hot melt adhesive on the pad; depositing an initial copper layer; attaching a dry film on the initial copper layer, exposing and developing the dry film; horizontally electroplating to form a circuit pattern of 7 to 8 microns; stripping the film to remove the dry film, and flash etching to remove the initial copper layer covered by the dry film.

[0139] Furthermore, for the Micro-LED chip, grinding the plate to remove the hot melt adhesive on the pad includes: first using a ceramic brush to grind the plate from the top of the hot melt adhesive, and then using a laser cleaning method to remove the hot melt adhesive on the pad.

[0140] Furthermore, for the Micro-LED chip, coating the hot melt adhesive specifically includes: melting the hot melt adhesive at high temperature in a vacuum box, coating the hot melt adhesive by silk screen printing, and leveling the hot melt adhesive coated on the surface of the solder pad and the auxiliary film.

[0141] Furthermore, for the Micro-LED chip, the auxiliary film is removed, and gold is applied to the pads and circuit patterns, including: removing the auxiliary film; applying hot melt adhesive on the surface of the pads and circuit patterns; laser cleaning to expose the pads on the side where the circuit pattern is located; and performing gold application on both ends of the pads.

[0142] Furthermore, for the Micro-LED chip, before applying hot melt adhesive on the solder pad and circuit pattern surface, the process also includes: plasma cleaning of the solder pad; and automatic optical inspection.

[0143] Furthermore, for the aforementioned Micro-LED chip, the integration method of the Micro-LED chip includes the following steps: forming a solder pad on an auxiliary film by a laser 3D forming method; the laser 3D forming method includes: defining a solder pad area on the auxiliary film in sequence, using a laser to melt copper slurry, so that the molten copper slurry drips onto the solder pad area drop by drop and solidifies to form a solder pad; forming a circuit pattern connected to the solder pad on the solder pad; specifically including: coating a hot melt adhesive on a side of the auxiliary film where the solder pad is provided, and the thickness of the hot melt adhesive is greater than the height of the solder pad; grinding the plate to remove the hot melt adhesive on the solder pad; depositing an initial copper layer; attaching a dry film on the initial copper layer, exposing and developing the dry film; horizontally electroplating to form a circuit pattern with a thickness of 7 to 8 microns; stripping the film to remove the dry film, and flash etching to remove the initial copper layer covered by the dry film; removing the auxiliary film, and coating the solder pad and the circuit pattern surface with hot melt adhesive; laser cleaning to expose the solder pad on the side where the circuit pattern is located; performing gold immersion treatment on both ends of the solder pad; and connecting the circuit pattern to the Micro-LED chip through the solder pad.

[0144] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0145] It is understandable that the above-mentioned embodiments only express several implementation methods of the present application, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present application. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, the above-mentioned technical features can be freely combined, and several deformations and improvements can be made, all of which fall within the scope of protection of the present application. Therefore, all equivalent transformations and modifications made to the scope of the claims of the present application shall fall within the scope of coverage of the claims of the present application, and the scope of protection of the patent of the present application shall be based on the attached claims.

Claims

1. A method for integrating a Micro-LED chip, characterized in that: The steps include: forming a pad on the auxiliary film by a laser 3D forming method; forming a circuit pattern on the pad that is connected to the pad; Remove the auxiliary film and perform double-sided gold deposition on the pads; and connect the circuit pattern to the Micro-LED chip through the pads.

2. The method for integrating a Micro-LED chip according to claim 1, characterized in that: The laser 3D forming method comprises: defining pad areas on the auxiliary film in sequence, melting copper slurry with laser, and making the molten copper slurry drip on the pad area one by one and solidify to form the pad.

3. The method for integrating a Micro-LED chip according to claim 2, characterized in that: The pad formed by solidification and accumulation of the copper paste is laser polished to form a cylindrical pad.

4. The method for integrating a Micro-LED chip according to claim 1, characterized in that: Before forming the pad on the auxiliary film, the method further includes: performing a roughening treatment on the auxiliary film, wherein the roughening treatment includes plasma etching or liquid etching.

5. The method for integrating a Micro-LED chip according to claim 1, characterized in that: A circuit pattern connected to the pad is formed on the pad, specifically including: Coating hot melt adhesive on one side of the auxiliary film where the pad is provided, and the thickness of the hot melt adhesive is greater than the height of the pad; Grind the board to remove the hot melt glue on the pad; depositing an initial copper layer; applying dry film on the initial copper layer, exposing and developing the dry film; Horizontal electroplating forms a circuit pattern of 7 to 8 microns; Stripping removes the dry film, and flash etching removes the initial copper layer covered by the dry film.

6. The method for integrating a Micro-LED chip according to claim 5, characterized in that: Grinding the plate to remove the hot melt adhesive on the pad includes: firstly grinding the plate from the top of the hot melt adhesive using a ceramic brush, and then removing the hot melt adhesive on the pad using a laser cleaning method.

7. The method for integrating a Micro-LED chip according to claim 5, characterized in that: The hot melt adhesive coating specifically includes: melting the hot melt adhesive at high temperature in a vacuum box, coating the hot melt adhesive by silk screen printing, and leveling the hot melt adhesive coated on the pad and the surface of the auxiliary film.

8. The method for integrating a Micro-LED chip according to claim 1, characterized in that: Remove the auxiliary film and perform double-sided immersion gold on the pad, including: Remove auxiliary membrane; Apply hot melt adhesive on the surface of the pad and circuit pattern; Laser cleaning to expose the pads on the side where the circuit pattern is located; Perform immersion gold treatment on both ends of the pad.

9. The method for integrating a Micro-LED chip according to claim 7, characterized in that: Before applying hot melt adhesive on the surface of the pad and circuit pattern, it also includes: plasma cleaning of the pad; automatic optical inspection.

10. The method for integrating a Micro-LED chip according to claim 1, characterized in that: The steps include: The pad is formed on the auxiliary film by a laser 3D forming method; the laser 3D forming method comprises: sequentially defining the pad area on the auxiliary film, using a laser to melt the copper slurry, so that the molten copper slurry drips on the pad area one by one and solidifies to form the pad; A circuit pattern connected to the pad is formed on the pad; specifically comprising: coating a hot melt adhesive on one side of the auxiliary film where the pad is provided, wherein the thickness of the hot melt adhesive is greater than the height of the pad; removing the hot melt adhesive on the pad by grinding the plate; depositing an initial copper layer; attaching a dry film on the initial copper layer, exposing and developing the dry film; horizontally electroplating to form a circuit pattern with a thickness of 7 to 8 microns; removing the dry film by stripping the film, and removing the initial copper layer covered by the dry film by flash etching; Remove the auxiliary film and apply hot melt adhesive on the surface of the pad and circuit pattern; Laser cleaning to expose the pads on the side where the circuit pattern is located; The two ends of the pad are treated with gold, and the circuit pattern is connected to the Micro-LED chip through the pad.

11. A Micro-LED chip, characterized in that: It is prepared by the integration method of Micro-LED chips; The integration method of the Micro-LED chip comprises the following steps: forming a pad on the auxiliary film by a laser 3D forming method; forming a circuit pattern on the pad that is connected to the pad; Remove the auxiliary film and perform double-sided gold deposition on the pads; and connect the circuit pattern to the Micro-LED chip through the pads.

12. The Micro-LED chip according to claim 11, characterized in that: The laser 3D forming method comprises: defining pad areas on the auxiliary film in sequence, melting copper slurry with laser, and making the molten copper slurry drip on the pad area one by one and solidify to form the pad.

13. The Micro-LED chip according to claim 12, characterized in that: The pad formed by solidification and accumulation of the copper paste is laser polished to form a cylindrical pad.

14. The Micro-LED chip according to claim 11, characterized in that: Before forming the pad on the auxiliary film, the method further includes: performing a roughening treatment on the auxiliary film, wherein the roughening treatment includes plasma etching or liquid etching.

15. The Micro-LED chip according to claim 11, characterized in that: A circuit pattern connected to the pad is formed on the pad, specifically including: Coating hot melt adhesive on one side of the auxiliary film where the pad is provided, and the thickness of the hot melt adhesive is greater than the height of the pad; Grind the board to remove the hot melt glue on the pad; depositing an initial copper layer; applying dry film on the initial copper layer, exposing and developing the dry film; Horizontal electroplating forms a circuit pattern of 7 to 8 microns; Stripping removes the dry film, and flash etching removes the initial copper layer covered by the dry film.

16. The Micro-LED chip according to claim 15, characterized in that: Grinding the plate to remove the hot melt adhesive on the pad includes: firstly grinding the plate from the top of the hot melt adhesive using a ceramic brush, and then removing the hot melt adhesive on the pad using a laser cleaning method.

17. The Micro-LED chip according to claim 15, characterized in that: The hot melt adhesive coating specifically includes: melting the hot melt adhesive at high temperature in a vacuum box, coating the hot melt adhesive by silk screen printing, and leveling the hot melt adhesive coated on the pad and the surface of the auxiliary film.

18. The Micro-LED chip according to claim 11, characterized in that: Remove auxiliary film, immerse gold on pads and circuit patterns, including: Remove auxiliary membrane; Apply hot melt adhesive on the surface of the pad and circuit pattern; Laser cleaning to expose the pads on the side where the circuit pattern is located; Perform immersion gold treatment on both ends of the pad.

19. The Micro-LED chip according to claim 17, characterized in that: Before applying hot melt adhesive on the surface of the pad and circuit pattern, it also includes: plasma cleaning of the pad; automatic optical inspection.

20. The Micro-LED chip according to claim 11, characterized in that: The integration method of the Micro-LED chip comprises the following steps: The pad is formed on the auxiliary film by a laser 3D forming method; the laser 3D forming method comprises: sequentially defining the pad area on the auxiliary film, using a laser to melt the copper slurry, so that the molten copper slurry drips on the pad area one by one and solidifies to form the pad; A circuit pattern connected to the pad is formed on the pad; specifically comprising: coating a hot melt adhesive on one side of the auxiliary film where the pad is provided, wherein the thickness of the hot melt adhesive is greater than the height of the pad; removing the hot melt adhesive on the pad by grinding the plate; depositing an initial copper layer; attaching a dry film on the initial copper layer, exposing and developing the dry film; horizontally electroplating to form a circuit pattern with a thickness of 7 to 8 microns; removing the dry film by stripping the film, and removing the initial copper layer covered by the dry film by flash etching; Remove the auxiliary film and apply hot melt adhesive on the surface of the pad and circuit pattern; Laser cleaning to expose the pads on the side where the circuit pattern is located; The two ends of the pad are treated with gold, and the circuit pattern is connected to the Micro-LED chip through the pad.

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