Substrate preparation method, mold and Micro-LED display unit

Abstract

The embodiment of the invention discloses a preparation method of a substrate, a mold and a Micro-LED display unit. When the substrate needs to be etched, the mold can be provided firstly, then the mold is connected to the substrate, and finally the substrate is etched through the etching holes in the mold. Compared with a small-spacing circuit process technology in the traditional technology, the preparation method of the substrate provided by the embodiment of the invention is developed and optimized, a negative film process or an improved semi-additive process process of the traditional technology is canceled, the requirements of products on equipment and materials are greatly reduced, the first pass yield of the products is improved, the manufacturing cost is reduced, and the production efficiency is improved. The process requirement and the etching precision requirement are greatly reduced, process transformation is easy to complete, and the core competitiveness of product cost and mass production is improved.

Description

Technical Field

[0001] This application relates to the field of display screen technology, and more particularly to a method for preparing a substrate, a mold, and a Micro-LED display unit. Background Technology

[0002] With the upgrade of micro-led products, the pitch and pad size are smaller, and the density of electronic assembly and the miniaturization of components are increasing. However, the cost sensitivity of small-pitch, highly integrated PCBs is very high. The main factors affecting the cost include: high-resolution dry film (10um dry film), high-resolution exposure machine (5um exposure machine), and low product yield (60%).

[0003] The exposure machine requires high precision: the fine detail of the circuitry necessitates a highly accurate process for converting Gerber files into photoresist films during plate making, as any minute error can lead to distortion or misalignment of the circuit pattern.

[0004] Etching is challenging to control: factors such as the concentration of the etching solution, temperature, and etching time must be strictly controlled. Even slight deviations can easily lead to problems like over-etching or under-etching, resulting in line widths that do not meet design requirements, or even open circuits or short circuits. Higher resolution dry films are required.

[0005] Existing manufacturing processes are costly, require high-precision materials and equipment, and have low first-pass yields, severely impacting product marketability. To address this, a novel technical solution is developed, taking into account the layout characteristics of micro-LED products, to improve first-pass yield while reducing manufacturing costs. This invention patent designs a nano-mold for the GAP area of ​​the PCB LED pads, using coating, molding, etching, and melting to complete the etching of the small-pitch area. Summary of the Invention

[0006] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This part of the invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0008] Therefore, a first aspect of the present invention provides a method for preparing a substrate.

[0009] A second aspect of the present invention provides a mold.

[0010] A third aspect of the present invention provides a Micro-LED display unit.

[0011] In view of the above, a method for preparing a substrate is provided according to a first aspect of the embodiments of this application, comprising:

[0012] A mold is provided, wherein the mold has etched holes;

[0013] The mold is connected to the substrate of the printed circuit board;

[0014] The substrate is etched using the etching holes.

[0015] In one feasible implementation, the step of providing a mold having etched holes includes:

[0016] Provide the mold body;

[0017] Based on the characteristics of the printed circuit on the substrate, the location of the etching holes on the mold body is determined.

[0018] Using a laser, holes are made in the mold body based on the specified opening position;

[0019] An adhesive is applied to the mold body to form an adhesive layer, thereby obtaining the mold.

[0020] In one feasible implementation, the step of using a laser to create an opening in the mold body based on the opening location further includes:

[0021] Mark points are prepared on the mold body;

[0022] The mold body is subjected to water washing and sandblasting to remove surface substances and / or oxide layers.

[0023] Following the step of using a laser to create an opening in the mold body based on the opening location, the method further includes:

[0024] The mold body is etched to remove carbonization and burrs from its surface;

[0025] A barrier layer is formed on the mold body.

[0026] In one feasible implementation, the step of determining the location of the etched holes on the mold body based on the characteristics of the printed circuit on the substrate includes:

[0027] Based on the characteristics of the printed circuits on the substrate, a first processing area and a second processing area of ​​the substrate are determined.

[0028] Based on the etching requirements of the first processing area, the location of the etching holes on the mold body is determined;

[0029] The first processing area requires an etching pitch of less than or equal to 40 μm, while the second processing area requires an etching pitch greater than that of the first processing area.

[0030] In one feasible implementation, the step of connecting the mold to the substrate of the printed circuit board includes:

[0031] By applying heat and pressure, the mold is bonded to the substrate using the adhesive layer on the mold, and the etching holes are arranged opposite to the area to be etched on the substrate.

[0032] In one feasible implementation, the step of etching the substrate using the etching holes includes:

[0033] During the etching process, the mold is positioned below the substrate;

[0034] The substrate is etched using the etching holes.

[0035] In one feasible implementation, the step of etching the substrate using the etching holes further includes:

[0036] Melt the adhesive layer between the mold and the substrate;

[0037] The mold is cleaned and re-coated, and then it is ready for reuse.

[0038] According to a second aspect of the embodiments of this application, a mold is provided for use in the substrate fabrication method as described in any of the above technical solutions, the mold comprising:

[0039] The mold body has multiple etched holes.

[0040] An adhesive layer that covers at least one surface of the mold body.

[0041] According to a third aspect of the embodiments of this application, a Micro-LED display unit is provided, wherein the Micro-LED display unit is prepared by the substrate preparation method described in any of the above technical solutions.

[0042] In one feasible implementation, the Micro-LED display unit includes:

[0043] substrate;

[0044] The display chip is connected to the substrate, and the area on the substrate where the display chip is disposed is the processing area;

[0045] The substrate preparation method is used to prepare a substrate for etching the processing area.

[0046] Compared with the prior art, the present invention has at least the following beneficial effects:

[0047] The substrate fabrication method provided in this application embodiment allows for the following steps when the substrate product requires fine-pitch etching: first, a mold is provided, then the mold is connected to the substrate, and finally, the substrate is etched using etching holes on the mold. This substrate fabrication method is an optimized development compared to traditional fine-pitch circuitry techniques. It eliminates the traditional tenting (subtractive process) or modified semi-additive process (MSAP), significantly reducing the equipment and material requirements, increasing the product's first-pass yield, lowering manufacturing costs, and greatly reducing process and etching precision requirements. It also facilitates process transitions and enhances the product's core competitiveness in terms of cost and mass production.

[0048] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0049] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0050] Figure 1 A schematic flowchart illustrating the steps of a substrate fabrication method according to an embodiment of this application;

[0051] Figure 2 A flowchart illustrating the process steps of a substrate fabrication method according to one embodiment of this application;

[0052] Figure 3 A schematic structural diagram of the mold provided in this application;

[0053] Figure 4 A schematic structural diagram illustrating the connection state between the mold and the substrate provided in this application;

[0054] Figure 5 for Figure 4 A magnified view of a portion of point A in the middle.

[0055] in, Figures 2 to 4 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0056] 210 mold, 220 substrate;

[0057] 211 Etched holes, 212 Mark points, 213 Adhesive layer, 214 Mold body. Detailed Implementation

[0058] The following description provides numerous specific details to offer a more thorough understanding of the technical solutions provided by this invention. However, it will be apparent to those skilled in the art that the technical solutions provided by this invention can be implemented without one or more of these details.

[0059] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0060] Exemplary embodiments according to the present invention will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the invention is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art.

[0061] This application takes into account the following difficulties of traditional processes:

[0062] 1. Challenges in Electroplating: Uniformity is difficult to guarantee. During electroplating, ensuring the uniformity of the plating layer is crucial. Improper control of process parameters such as the composition, concentration, temperature, and current density of the plating solution can easily lead to uneven plating thickness, affecting subsequent circuit etching. High current-carrying / top-bottom current-conducting electroplating lines are required, and production sizes should not be too large. Fixed equipment performance and size structures improve the consistency of current distribution, reduce the potential difference between different areas of the product surface, and improve plating uniformity. (Current density is reduced by 30% compared to conventional product parameters, first-pass yield is reduced by more than 20%, and equipment / material costs are increased by more than 400% compared to conventional parameters. The required electroplating lines and electroplating requirements are stringent, and most need to be imported.)

[0063] 2. Circuit Design Challenges: The fine detail of the circuitry requires extremely high precision in the conversion of Gerber files into photoresist during plate making. Even the slightest error can lead to distortion or misalignment of the circuit pattern. This necessitates a high-specification exposure machine with an exposure resolution of 5µm or lower to handle dry films with dimensions of 10µm or less. (Dry films are extremely expensive, costing 10-20 times more than conventional dry films, which are typically manufactured by DuPont, Hitachi, etc.)

[0064] 3. Etching Challenges: Etching is difficult to control, requiring strict control of factors such as the concentration, temperature, and etching time of the etching solution. Even slight deviations can easily lead to over- or under-etching, resulting in line widths that do not meet design requirements, or even open or short circuits. Higher resolution dry films are needed. Differences in copper thickness and spacing in different areas cause inconsistent etching conditions. Combined with the pooling effect, to ensure etching consistency, the lateral etching amount is generally about twice the copper thickness. This necessitates even higher dry film resolution.

[0065] In summary, the equipment, chemicals, and materials required for high-precision small-pitch products (pitch ≤ 40um) are 10 to 20 times more expensive than those for conventional products. Production capacity and output are relatively limited, and very little can be allocated to the micro-LED industry. Coupled with the high cost, this is not conducive to the development of the micro-LED industry towards miniaturized and highly integrated products.

[0066] like Figure 1 As shown, a method for preparing a substrate is provided according to a first aspect of the embodiments of this application, comprising:

[0067] Step 101: Provide a mold with etched holes;

[0068] Step 102: Connect the mold to the printed circuit board;

[0069] Step 103: Etch the substrate using etching holes.

[0070] like Figures 1 to 5As shown in the embodiment of this application, when the substrate 220 needs to be etched with small pitch, a mold 210 can be provided first, then the mold 210 can be connected to the substrate 220, and finally the PCB substrate 220 can be etched using the etching holes 211 on the mold 210. The substrate preparation method provided in this application embodiment is developed and optimized compared with the small pitch circuit process technology in the traditional technology. It eliminates the traditional tenting (subtractive process) or modified semi-additive process (MSAP), which greatly reduces the product's demand for equipment and materials, improves the product's first pass rate, reduces manufacturing costs, greatly reduces process requirements and etching accuracy requirements, facilitates process transformation, and enhances the core competitiveness of the product in terms of cost and mass production.

[0071] The substrate preparation method provided in this application embodiment uses a mold 210 with etching holes 211 to etch the substrate 220, which makes it easy to ensure etching accuracy. It can reduce the strict requirements on factors such as the concentration, temperature and etching time of the etching solution during the etching process, reduce the probability of etched or under-etched products, and does not rely on expensive equipment, chemicals and materials. It is particularly suitable for the processing of small-pitch products, which is conducive to the development of the micro-LED industry towards miniaturized and highly integrated products.

[0072] In one feasible implementation, the step of providing a mold 210, on which etched holes 211 are formed, includes: providing a mold body 214; determining the opening position of the etched holes 211 on the mold body 214 based on the characteristics of the printed circuit on the substrate; using a laser to make holes in the mold body 214 based on the opening position; coating the mold body 214 with adhesive to form an adhesive layer 213, and obtaining the mold 210.

[0073] This technical solution further provides specific steps for creating etching holes 211 in the mold 210. First, a mold body 214 is provided. Then, based on the characteristics of the printed circuit on the substrate (including layout characteristics), the location of the etching holes is determined based on the areas on the substrate that need etching. Next, a laser is used to create holes in the mold body 214. Then, an adhesive layer 213 is applied to the mold body 214 to obtain the mold 210. This allows the location of the mold 210 to be adapted to the etching requirements of the substrate 220, improving etching accuracy. Furthermore, the adhesive layer 213 allows the mold 210 to be bonded to the substrate 220, making the connection and fixation of the mold 210 more reliable, reducing the probability of the mold 210 loosening, and allowing the mold 210 to better shield non-etched areas, further improving etching accuracy. Furthermore, after etching is completed, the mold 210 and the substrate 220 can be separated by melting the adhesive layer 213, which facilitates the production and processing of the substrate. Moreover, the mold 210 can be reused, which can further reduce the substrate manufacturing cost and thus reduce the manufacturing cost of the display device.

[0074] In some examples, adhesive is applied to the mold body 214 to form an adhesive layer 213. The specific steps to obtain the mold 210 include: applying a 2-3 μm layer of acid-resistant thermosetting adhesive, similar to photoresist (similar dry film characteristics), to the side where the template body is connected to the substrate 220. This adhesive is resistant to etching solution erosion, and the surface of the adhesive layer 213 is protected with a PET film to prevent foreign matter from adhering during the process.

[0075] like Figure 3 and Figure 4 As shown, in one feasible embodiment, prior to the step of using a laser to create an opening in the mold body 214 based on the opening location, the method further includes: preparing Mark points 212 on the mold body 214; and performing water washing and sandblasting on the mold body 214 to remove surface materials and / or oxide layers.

[0076] In this technical solution, before applying the adhesive, Mark points 212 can be prepared on the mold body 214. Specifically, the mold body 214 can be rectangular, and Mark points 212 can be set at the corners of the mold body 214 to facilitate the precise connection between the mold 210 and the substrate 220 and ensure etching accuracy.

[0077] In this technical solution, the mold body 214 can also be washed and sandblasted to remove surface substances / oxidation, providing a consistent bearing surface for laser opening, preventing uneven absorption capacity in the opening area due to oxidation and foreign matter, which can lead to abnormal holes of different sizes and improve the opening accuracy of the etched hole 211.

[0078] In one feasible implementation, after the step of using a laser to create an opening in the mold body 214 based on the opening location, the method further includes: etching the mold body 214 to remove carbonization and burrs from the surface of the mold body 214; and forming a barrier layer on the mold body 214.

[0079] In this technical solution, after the opening of the mold body 214 is completed, the carbonization and microburrs on the contour surface of the mold body 214 by the laser can be removed by micro-etching with a mild acid solution. The etching depth is 0.1-0.2um. Then, a barrier layer with a thickness of 0.5-1um is formed on the mold body 214. The barrier layer can be made of tantalum and / or chromium metal to prevent the subsequent etching solution from corroding or contaminating the mold 210, which is conducive to the reuse of the mold 210.

[0080] In some examples, the thickness of the mold body 214 can be 10-20um, and the etched hole 211 can be a rectangular hole of 20*100um. During the hole-making process, the picosecond laser can be used for preliminary repair of the progress profile to further improve the hole-making accuracy.

[0081] In one feasible implementation, the step of determining the location of the etched hole 211 on the mold body 214 based on the characteristics of the printed circuit on the substrate 220 includes: determining a first processing area and a second processing area of ​​the substrate 220 based on the characteristics of the printed circuit on the substrate 220; determining the location of the etched hole 211 on the mold body 214 based on the etching requirements of the first processing area; wherein the first processing area requires an etching pitch of less than or equal to 40 μm, and the second processing area requires an etching pitch greater than that of the first processing area.

[0082] In this technical solution, considering the characteristics of the printed circuits on the substrate 220, only the RGB chip area requires a small pitch of 30-40µm, while other line areas meet the conventional 75µm / 75µm linewidth / pitch level. Therefore, partitioned etching can be performed, i.e., conventional areas are processed using conventional methods. Thus, during the etching of the substrate 220 using the fabrication method provided in this application embodiment, only areas requiring small pitch etching can be etched using the etching holes 211, while other areas with less stringent pitch requirements can be etched using conventional methods. This allows for partitioned etching of the substrate 220, further reducing process costs and facilitating the fabrication of the mold 210, thus simplifying the implementation of the fabrication method provided in this application embodiment.

[0083] like Figure 2 and Figure 4As shown, in one feasible embodiment, the step of connecting the mold 210 to the substrate 220 of the printed circuit includes: bonding the mold 210 to the substrate 220 of the printed circuit by hot melting and pressurizing, using the adhesive layer 213 on the mold 210, and the etching hole 211 is disposed opposite to the area to be etched on the substrate 220.

[0084] In this technical solution, a specific method for connecting the mold 210 and the substrate 220 is further provided. The adhesive layer 213 on the mold 210 can be melted and adhered to the surface of the substrate 220 by hot melting and pressurizing, leaving only the spacing position to be etched exposed. Subsequently, the substrate 220 can be etched using the etching hole 211.

[0085] like Figure 4 and Figure 5 As shown, in one feasible embodiment, the step of etching the substrate 220 using the etching hole 211 includes: during the etching process, positioning the mold 210 below the substrate 220; and etching the substrate 220 using the etching hole 211.

[0086] In this technical solution, etching holes 211 are further provided to etch the substrate 220. During the etching process, the mold 210 is located below the substrate 220. This arrangement can reduce the impact of the pool effect on the etching accuracy and improve the etching uniformity.

[0087] Among them, such as Figure 5 As shown, the red line within the white box indicates the area that needs to be etched. The pads can be masked by etching holes, and the etchant can be used to etch the pads, splitting them into two pads, thus completing the fabrication of a 30um small pitch pad.

[0088] It is understandable that the "pool effect" during the etching process refers to the inability of fresh etching solution to reach the metal surface due to obstruction by the etching solution within the structure, thus preventing the exchange of etching solution between the structure and fresh solution. The preparation method provided in this application, where the etching solution fills the etching hole 211 from bottom to top, can suppress the pool effect.

[0089] like Figure 2 As shown, in one feasible embodiment, after the step of etching the substrate 220 using the etching hole 211, the method further includes: melting the adhesive layer 213 between the mold 210 and the substrate 220; cleaning and re-coating the mold 210, and the mold 210 entering a reusable state.

[0090] In this technical solution, after etching the substrate 220, the 2-3µm thick adhesive layer 213 between the PCB and the mold body 214 can be melted away using an organic stripping solution. Then, through separation and washing, melt residues on the surfaces of the substrate 220 and the mold 210 are removed. Afterward, the mold 210 is ultrasonically washed, dried, and coated with adhesive. This yields a reusable mold 210, which can be reused in subsequent applications, further reducing the cost of the manufacturing process.

[0091] The substrate fabrication method provided in this application embodiment can be tailored to the characteristics of the printed circuits on the substrate. Only the RGB chip area requires a small pitch of 30-40µm, while other circuit areas meet the conventional 75µm / 75µm linewidth / pitch levels. By laser-opening the mold 210, the GAP areas of the RGB chips that need to be etched are achieved. Through coating and adhesive application, subsequent bonding with the substrate 220 surface and etching by the etching solution are achieved, ultimately completing the partitioned etching of the small-pitch area. At the same time, the mold 210 can also be reused.

[0092] like Figure 3 As shown, according to a second aspect of the present application, a mold 210 is provided for use in the preparation method of a substrate as described above. The mold 210 includes: a mold body 214, on which a plurality of etched holes 211 are formed; and an adhesive layer 213, which covers at least one surface of the mold body 214.

[0093] The mold 210 provided in this application embodiment is applied to the substrate preparation method of any of the above-described technical solutions, and therefore the mold 210 possesses all the beneficial effects of the preparation method of the above-described technical solutions.

[0094] The mold 210 provided in this embodiment includes a mold body 214 and an adhesive layer 213. Based on this, during the use of the mold 210, the mold 210 can be bonded to the substrate 220. Finally, the substrate 220 is etched using the etching holes 211 on the mold 210. After etching is completed, the 2-3 μm thick adhesive layer 213 between the PCB and the mold body 214 can be melted away using an organic stripping solution. Then, the melt film impurities on the surface of the substrate 220 and the mold 210 are removed by separation washing. Afterward, the mold 210 is ultrasonically washed, dried, and coated with adhesive. Thus, a reusable mold 210 can be obtained and reused in subsequent uses. The mold 210 provided in this application embodiment, combined with the substrate preparation method provided in this application embodiment, is developed and optimized compared with the small-pitch circuit process technology in the traditional technology. The negative film process or the modified semi-additive process of the traditional process is eliminated, which greatly reduces the product's demand for equipment and materials, improves the product's first pass rate, reduces manufacturing costs, greatly reduces process requirements and etching accuracy requirements, makes it easy to complete process transformation, and enhances the core competitiveness of the product in terms of cost and mass production.

[0095] like Figures 1 to 5 As shown, a Micro-LED display unit is provided according to a third aspect of the embodiments of this application. The Micro-LED display unit is prepared by the substrate preparation method of any of the above-described technical solutions.

[0096] Since the Micro-LED display unit provided in this application embodiment is prepared by the substrate preparation method of any of the above technical solutions, the Micro-LED display unit has all the beneficial effects of the substrate preparation method of the above technical solutions, which will not be elaborated here.

[0097] The substrate fabrication method provided in this application is particularly suitable for small-pitch processing. With the upgrading of Micro-LED display unit products, the pitch and pad size are smaller, and the electronic assembly density and component miniaturization are high. Therefore, the fabrication method provided in this application is particularly suitable for processing substrate 220 with small-pitch processing requirements. Thus, the Micro-LED display unit fabricated by the fabrication method provided in this application has lower cost and higher processing precision.

[0098] In one feasible implementation, the Micro-LED display unit includes: a substrate 220; a display chip connected to the substrate 220, wherein the area on the substrate 220 where the display chip is disposed is a processing area; and a substrate preparation method is used to etch the processing area.

[0099] This technical solution further improves the structural composition of the Micro-LED display unit. The substrate fabrication method is used to etch the area on the substrate 220 where the display chip is located. The Micro-LED display unit can include a display chip and the substrate 220. The substrate fabrication method provided in this application embodiment is used to etch the area on the substrate 220 where the display chip is located. This setting takes into account that, according to the layout characteristics of Micro-LED display unit products, only the RGB chip area requires a small pitch of 30-40um, while other line areas meet the conventional 75um / 75um linewidth / pitch level. Therefore, partition etching can be performed. The areas other than the processing area, that is, the conventional areas, are processed using conventional methods. The small-pitch areas, that is, the areas on the substrate 220 where the display chip is located, are etched using the substrate fabrication method provided in this application embodiment. This makes the etching more targeted and can greatly reduce the process requirements and etching accuracy in terms of product yield and manufacturing cost.

[0100] Example

[0101] The substrate preparation method provided in this application includes the following steps:

[0102] Step 1: Mold 210 fabrication: Layout data processing → Pre-treatment of coated mold 210 → Laser opening → Carbonization / deburring chemical treatment → Coating → Single-sided adhesive application → Warehousing;

[0103] Step 2: Mold 210 with adhesive masking for partitioned etching process: PCB to be etched → Micron mold 210 + PCB fast pressing → Etching → Demolding / washing → Micron mold 210 cleaning and recycling → AOI → Warehousing.

[0104] Among them, layout data processing: the areas that need to be opened are selected from the PCB data and processed to form laser layout data, and Mark points 212 are added to the four corners of the mold 210 for later fast pressing alignment.

[0105] Among them, the pretreatment of the coating mold 210: the rough mold (10-20um thickness) is washed and sandblasted to remove surface substances / oxidation, so as to provide a consistent bearing surface for laser opening; (to prevent the uneven absorption capacity of the opening area due to oxidation and foreign matter, resulting in abnormal holes of different sizes)

[0106] Among them, the laser opening: a rectangular window of 20*100um is formed by UV laser processing, and the initial contour is repaired by picosecond laser.

[0107] Among them, the carbonization / burr chemical treatment: the carbonization and microburrs on the contour surface are removed by micro-etching with a mild acid solution, with an etching depth of 0.1-0.2um;

[0108] Among them, the coating: a 0.5-1um layer of tantalum / chromium metal is coated on the surface to prevent the subsequent etching solution from corroding / contaminating the micron mold 210;

[0109] Among them, single-sided adhesive is applied to the BOT side with a 2-3um layer of acid-resistant thermosetting adhesive, similar to photoresist (similar to dry film characteristics), which can resist the erosion of etching solution. The surface is protected with PET film to prevent foreign matter from adhering during the process.

[0110] Among them, mold 210+PCB fast pressing: the adhesive on mold 210 is melted and adhered to the PCB surface by hot melting and pressure, only exposing the spacing positions that need to be etched.

[0111] Etching: During etching, the mold 210 faces downward to reduce the pooling effect and improve etching uniformity.

[0112] Among them, demolding / washing: the 2-3um thermosetting adhesive layer between the PCB and the mold 210 is melted away by organic demolding solution, and the melted film impurities on the surface of the PCB and the mold 210 are removed by separation and washing.

[0113] Among them, mold 210 is cleaned and recycled: mold 210 is ultrasonically washed, dried and coated with adhesive for multiple uses.

[0114] In this invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0115] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0116] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0117] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a substrate, characterized in that, include: A mold is provided, wherein the mold has etched holes; The mold is connected to the substrate of the printed circuit board; The substrate is etched using the etching holes.

2. The method for preparing the substrate according to claim 1, characterized in that, The step of providing a mold, wherein the mold has etched holes, includes: Provide the mold body; Based on the characteristics of the printed circuit on the substrate, the location of the etching holes on the mold body is determined. Using a laser, holes are made in the mold body based on the specified opening position; An adhesive is applied to the mold body to form an adhesive layer, thereby obtaining the mold.

3. The method for preparing the substrate according to claim 2, characterized in that, Prior to the step of using a laser to create a hole in the mold body based on the opening position, the method further includes: Mark points are prepared on the mold body; The mold body is subjected to water washing and sandblasting to remove surface substances and / or oxide layers. Following the step of using a laser to create a hole in the mold body based on the specified opening position, the method further includes: The mold body is etched to remove carbonization and burrs from its surface; A barrier layer is formed on the mold body.

4. The method for preparing the substrate according to claim 2, characterized in that, Based on the characteristics of the printed circuit on the substrate, the step of determining the location of the etched holes on the mold body includes: Based on the characteristics of the printed circuits on the substrate, a first processing area and a second processing area of ​​the substrate are determined. Based on the etching requirements of the first processing area, the location of the etching holes on the mold body is determined; The first processing area requires an etching pitch of less than or equal to 40 μm, while the second processing area requires an etching pitch greater than that of the first processing area.

5. The method for preparing a substrate according to any one of claims 1 to 4, characterized in that, The step of connecting the mold to the substrate of the printed circuit board includes: By applying heat and pressure, the mold is bonded to the substrate of the printed circuit using the adhesive layer on the mold, and the etching holes are arranged opposite to the area to be etched on the substrate.

6. The method for preparing a substrate according to any one of claims 1 to 4, characterized in that, The step of etching the substrate using the etching holes includes: During the etching process, the mold is positioned below the substrate; The substrate is etched using the etching holes.

7. The method for preparing a substrate according to any one of claims 1 to 4, characterized in that, Following the step of etching the substrate using the etching holes, the method further includes: Melt the adhesive layer between the mold and the substrate; The mold is cleaned and re-coated, and then it is ready for reuse.

8. A mold, characterized in that, The method for preparing a substrate according to any one of claims 1 to 7, wherein the mold comprises: The mold body has multiple etched holes. An adhesive layer that covers at least one surface of the mold body.

9. A Micro-LED display unit, characterized in that, The Micro-LED display unit is prepared by the method of preparing the substrate according to any one of claims 1 to 7.

10. The Micro-LED display unit according to claim 9, characterized in that, The Micro-LED display unit includes: substrate; The display chip is connected to the substrate, and the area on the substrate where the display chip is disposed is the processing area; The substrate preparation method is used to prepare a substrate for etching the processing area.

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