A method and apparatus for manufacturing a capacitor embedded printed wiring board

Abstract

This invention relates to a method and apparatus for manufacturing a capacitor-embedded printed circuit board (PCB). The invention involves first drilling a first hole in a multilayer PCB, followed by copper plating within the hole; then, resin plugging the first hole, followed by a second drilling process in the resin-plugged area; attaching a carrier film to the first surface of the PCB, and placing a pre-set capacitor into the target hole along the second surface of the PCB; performing a first filling process with adhesive along the second surface of the PCB; and finally, removing the coating film from the first surface of the PCB and performing a second filling process with adhesive along the first surface of the PCB. Through these steps, the invention achieves precise positioning and uniform filling of the capacitor, solving problems such as filling defects, component fragility, and inaccurate positioning when embedding vertical capacitors, thereby improving the reliability and product quality of the printed circuit board.

Description

Technical Field

[0001] This invention relates to the field of PCB manufacturing technology, specifically to a method and apparatus for manufacturing a capacitor-embedded printed circuit board. Background Technology

[0002] Embedding passive components in printed circuit boards (PCBs) to improve system integration and electrical performance has become an important development direction for high-density interconnect technology. Ceramic capacitors, especially multilayer ceramic chip capacitors, are widely regarded as the first choice for embedded capacitors in PCBs due to their non-polarity, small size, low parasitic inductance, good high-temperature resistance, wide capacitance range, and complete range of medium and low voltage ratings. Furthermore, they benefit from the cost advantages brought by mass production. However, traditional embedding methods often place capacitors flat within inner layers of the circuitry, which not only occupies a large amount of planar space but also limits further optimization of high-frequency performance and power integrity. To overcome this limitation, one approach is to vertically embed ceramic capacitors within pre-fabricated vias in the PCB. By changing the device orientation, the current loop can be shortened, parasitic parameters reduced, and signal integrity and system reliability significantly improved. This also protects the embedded capacitors from external mechanical stress, thermal stress, and environmental factors. However, this novel concept faces severe challenges in its implementation: a carrier film needs to be pre-attached on one side to fix the capacitor, followed by filling the hole with dielectric material or resin. However, the vertically placed ceramic capacitor forms a narrow and deep gap with the hole wall, which easily leads to defects such as filling voids and insufficient adhesive, seriously affecting insulation performance and long-term reliability. More importantly, ceramic capacitors are brittle devices. If they are subjected to additional extrusion, bending, or thermal mismatch stress during subsequent processes such as lamination, curing, and drilling, cracks or even breakage will be induced, leading to device failure.

[0003] Therefore, how to achieve defect-free filling of the hole and effectively control the mechanical stress during the processing while ensuring the precise vertical positioning of the capacitor has become the core problem restricting the engineering application of the technology. Summary of the Invention

[0004] In view of the above problems, embodiments of the present invention provide a method and apparatus for manufacturing capacitor-embedded printed circuit boards, which solves the problem that the prior art requires pre-applying a carrier film on one side to fix the capacitor, and then filling the hole with dielectric material or resin. However, the vertically placed ceramic capacitor forms a narrow and deep gap with the hole wall, which is very easy to produce defects such as filling voids and missing glue, which seriously affects the insulation performance and long-term reliability.

[0005] According to one aspect of the present invention, a method for manufacturing a capacitor-embedded printed circuit board is provided, the method comprising: S1, Obtain the PCB multilayer board, perform the first drilling process on the PCB multilayer board to make the first drill hole, and perform copper plating process on the first drill hole. S2, perform resin plugging treatment on the first drilled hole to drive the resin plugged hole area, and perform a second drilling treatment in the resin plugged hole area to create the target hole. After completing the second drilling treatment, perform the first outer layer circuit treatment on the PCB multilayer board. S3, attach a carrier film to the first surface of the PCB multilayer board, and place a preset capacitor into the target hole along the second surface of the PCB multilayer board, with the first end of the capacitor abutting against the carrier film; S4, perform a first filling process on the target hole along the second surface of the PCB multilayer board to fill and cure the second end of the capacitor; S5, after peeling off the automotive film on the first surface of the PCB multilayer board, a second filling process is performed on the target hole along the first surface of the PCB multilayer board to fill and cure the first end of the capacitor.

[0006] In some embodiments, in step S4, the target hole is first filled with adhesive along the second surface of the PCB multilayer board, specifically including: Pure adhesive is attached to the first capacitor area on the second surface of the PCB multilayer board, wherein the first capacitor area is the area of ​​the target hole on the second surface of the PCB multilayer board and the projected area of ​​the first capacitor area is larger than the projected area of ​​the target hole. Pure adhesive is pressed into the target hole using a vacuum fast pressing device, so that the pure adhesive fills the gap between the second end of the capacitor and the target hole.

[0007] In some embodiments, in step S5, a second filling process is performed on the target hole along the first surface of the PCB multilayer board, specifically including: Pure adhesive is attached to the second capacitor region on the first surface of the PCB multilayer board, wherein the second capacitor region is the region of the target hole on the first surface of the PCB multilayer board and the projected area of ​​the second capacitor region is larger than the projected area of ​​the target hole. Pure adhesive is pressed into the target hole using a vacuum fast pressing device, so that the pure adhesive fills the gap between the first end of the capacitor and the target hole.

[0008] In some implementations, step S5 is followed by: S6, a connecting plate is pressed onto the first and / or second surfaces of the PCB multilayer board; S7, Laser processing is performed on the PCB multilayer board to create laser holes in the first capacitor area and / or the second capacitor area. S8, copper filling is performed on the laser holes, and a second outer layer circuit processing is performed on the PCB multilayer board to complete the circuit fabrication of the capacitor component.

[0009] In some embodiments, in step S6, the connecting plate includes at least one PP layer and at least one copper foil layer.

[0010] In some implementations, after the first drilling process and / or after the second drilling process and / or after the laser treatment, the PCB multilayer board is further subjected to a de-adhesive treatment.

[0011] In some embodiments, in step S3, the capacitor is vertically inserted into the target hole.

[0012] In some implementations, the length of the capacitor is less than the thickness of the PCB multilayer board.

[0013] In some implementations, step S1 involves obtaining a multilayer PCB board, specifically including: The core board is obtained through core board blanking, inner layer dry film processing, inner layer etching, and inner layer AOI processing. Multiple core boards are laminated into a multilayer PCB for cranes through browning, pressing, and grinding processes.

[0014] According to another aspect of the present invention, an apparatus for manufacturing a capacitor-embedded printed circuit board is provided, characterized in that the apparatus is used to perform the above-described method for manufacturing a capacitor-embedded printed circuit board.

[0015] The present invention provides a method and apparatus for manufacturing a capacitor-embedded printed circuit board, the advantages of which are as follows: The present invention performs a first drilling process on a multilayer PCB to create a first hole, and then performs copper plating on the first hole; the first hole is then filled with resin, and a second drilling process is performed in the resin-filled area; a carrier film is attached to the first surface of the multilayer PCB, and a pre-set capacitor is placed into the target hole along the second surface of the multilayer PCB; a first filling process of adhesive is performed on the target hole along the second surface of the multilayer PCB; after removing the automotive film from the first surface of the multilayer PCB, a second filling process of adhesive is performed on the target hole along the first surface of the multilayer PCB. Through the above steps, the present invention achieves precise positioning and uniform filling of the capacitor, solving the problems of filling defects, component fragility, and inaccurate positioning when embedding vertical capacitors, thereby improving the reliability and product quality of the printed circuit board.

[0016] The above description is merely an overview of the technical solutions of the embodiments of the present invention. In order to better understand the technical means of the embodiments of the present invention and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0017] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This diagram illustrates a first process flow of a capacitor-embedded printed circuit board manufacturing method according to an embodiment of the present invention. Figure 2 This diagram illustrates the second process flow of a capacitor-embedded printed circuit board manufacturing method according to an embodiment of the present invention. Figure 3 This diagram illustrates the first drilling process of a PCB multilayer board according to an embodiment of the present invention. Figure 4 A schematic diagram of the copper plating process for a PCB multilayer board according to an embodiment of the present invention is shown. Figure 5 A schematic diagram of resin-filled via processing of PCB multilayer boards according to an embodiment of the present invention is shown. Figure 6 This diagram illustrates the second drilling process for a PCB multilayer board according to an embodiment of the present invention. Figure 7 This diagram illustrates the first outer layer circuit processing of a PCB multilayer board according to an embodiment of the present invention. Figure 8 This diagram illustrates a PCB multilayer board with a carrier film attached to the first surface and capacitors mounted, according to an embodiment of the present invention. Figure 9 This diagram illustrates the first glue filling process for a PCB multilayer board according to an embodiment of the present invention. Figure 10 This diagram illustrates the second adhesive filling process for a PCB multilayer board according to an embodiment of the present invention. Figure 11 This diagram illustrates the installation of capacitors on a multilayer PCB board according to an embodiment of the present invention.

[0018] Figure label: 10. PCB multilayer board; 11. First drilled hole; 12. First copper plating layer; 13. Resin plugging area; 14. Target hole; 15. First outer layer circuit; 16. Capacitor; 17. Carrier film; 18. Pure glue; 19. First glue filling treatment to fix the shape; 20. Second glue filling treatment to fix the shape. Detailed Implementation

[0019] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0020] Example 1: Figure 1 This invention illustrates a first embodiment of a method for fabricating a capacitor-embedded printed circuit board, addressing the problem in existing technologies where a carrier film is pre-attached on one side to fix the capacitor, followed by filling the hole with dielectric material or resin. However, this often results in narrow, deep gaps between the vertically placed ceramic capacitor and the hole wall, easily leading to defects such as filling voids and insufficient adhesive, severely impacting insulation performance and long-term reliability. This method includes: S1, Obtain the PCB multilayer board, perform the first drilling process on the PCB multilayer board to make the first drill hole, and perform copper plating process on the first drill hole. S2, perform resin plugging treatment on the first drilled hole to drive the resin plugged hole area, and perform a second drilling treatment in the resin plugged hole area to create the target hole. After completing the second drilling treatment, perform the first outer layer circuit treatment on the PCB multilayer board. S3, attach a carrier film to the first surface of the PCB multilayer board, and place the preset capacitor into the target hole along the second surface of the PCB multilayer board, with the first end of the capacitor abutting against the carrier film. S4, perform the first filling treatment on the target hole along the second surface of the PCB multilayer board to fill and cure the second end of the capacitor; S5. After peeling off the automotive film on the first surface of the PCB multilayer board, a second filling process is performed on the target hole along the first surface of the PCB multilayer board to fill and cure the first end of the capacitor.

[0021] In steps S1-S5, a multilayer PCB refers to a printed circuit board made by alternating layers of conductive patterns and insulating substrates through a lamination process. The board material provides a platform for complex circuit connections and device mounting.

[0022] The first drilling process refers to creating a hole that penetrates or partially penetrates the PCB multilayer board using methods such as mechanical drilling or laser drilling. This first drilling provides the basic structure for subsequent process steps.

[0023] Copper plating refers to depositing a layer of copper on the wall of the first drilled hole to create a conductive path. This process is typically achieved through techniques such as electroless copper plating and electroplating, aiming to enhance the conductivity and mechanical strength of the hole wall.

[0024] Resin plugging refers to filling the first drilled hole with resin material and allowing it to cure to form a resin-plugged area. This process aims to provide a flat surface and a stable substrate for subsequent drilling and wiring. The second drilling process involves drilling again on the PCB multilayer board where the resin-plugged area has been formed to create the target hole within that area.

[0025] The target hole is used to accommodate the capacitor. The target hole refers to a cavity formed within the resin plugging area through a second drilling process. The size and location of the hole are precisely designed to ensure accurate installation and positioning of the capacitor.

[0026] The first outer layer circuit processing refers to the fabrication of conductive lines on the outer surface of a multilayer PCB board. This process typically includes steps such as pattern transfer, etching, and film removal, aiming to create external circuitry that connects to capacitors.

[0027] A carrier film is a thin film material temporarily attached to the surface of a multilayer PCB board to provide support and positioning during capacitor mounting. The carrier film can be removed after the initial fixing of the capacitors is complete.

[0028] A capacitor is a passive electronic component used to store electrical charge, such as a multilayer ceramic chip capacitor. Capacitors are designed to be vertically embedded within a multilayer PCB to optimize circuit performance and space utilization.

[0029] The first filling process involves filling the target hole with adhesive material to secure the second end of the capacitor. This process aims to ensure the stability of the capacitor within the hole and provide initial insulation protection.

[0030] The second filling process involves filling the target hole with adhesive material again after the first filling process to secure the first end of the capacitor. This process aims to achieve complete fixation and insulating encapsulation of the capacitor.

[0031] This embodiment provides a method for fabricating a printed circuit board with embedded capacitors. See also: Figures 3-11 First, a multilayer PCB board is obtained. Multilayer PCB boards can be manufactured using conventional lamination processes, such as laminating multilayer core boards and prepregs. Then, the multilayer PCB board undergoes its first drilling process to create the first holes; for example... Figure 3 As shown, a first drilled hole 11 is made on the PCB multilayer board 10. The first drilling can be performed using mechanical drilling equipment, such as using a drill bit to drill a through hole at a predetermined location. After the first drilled hole is completed, copper plating is applied to the inside of the first drilled hole; for example... Figure 4 As shown, a first copper plating layer 12 is fabricated on the PCB multilayer board 10. The copper plating process can be achieved by combining chemical copper plating and electroplating to form a uniform copper layer with good conductivity on the hole walls.

[0032] Next, the first drilled hole is filled with resin to form a resin-filled area; such as Figure 5As shown, a resin-filled via region 13 is fabricated on the PCB multilayer board 10. The resin-filled via process can be performed using methods such as screen printing or vacuum filling, where liquid resin is filled into the first drilled hole and then cured. The resin-filled via region aims to provide a flat and insulating surface. Subsequently, a second drilling process is performed in the resin-filled via region to create the target hole, such as... Figure 6 As shown, target hole 14 is fabricated on PCB multilayer board 10. The second drilling process can be performed using laser drilling or high-precision mechanical drilling equipment to ensure the dimensional and positional accuracy of the target hole. After completing the second drilling process, the PCB multilayer board undergoes its first outer layer circuit processing, such as... Figure 7 As shown, a first outer layer circuit 15 is fabricated on a multilayer PCB board 10. The first outer layer circuit processing may include conventional process steps such as pattern transfer, etching, and film removal to form external circuits that connect to capacitors.

[0033] Furthermore, a carrier film is attached to the first surface of the PCB multilayer board, such as... Figure 8 As shown, a carrier film 17 is attached to the PCB multilayer board 10. The carrier film can be a polymer film with a certain degree of adhesion, such as polyester film or polyimide film, and its function is to temporarily fix the capacitor in subsequent steps. Simultaneously, the pre-set capacitor is placed into the target hole along the second surface of the PCB multilayer board, as shown. Figure 8 As shown, a capacitor 16 is placed in the target hole 14 of the PCB multilayer board 10. The capacitor can be placed using an automated pick-and-place device to ensure accurate placement into the target hole. During this process, the first end of the capacitor abuts against the carrier film, thereby achieving initial positioning and support of the capacitor within the target hole.

[0034] Subsequently, the target hole is filled with adhesive along the second surface of the PCB multilayer board, such as... Figure 9 As shown, pure adhesive is applied to the second surface of the PCB multilayer board 10; the final shape after pressing the pure adhesive into the target hole is as follows. Figure 10 As shown. The first filling treatment can be performed by dispensing, scraping, or spraying, filling the target hole with liquid adhesive material to fill and cure the second end of the capacitor. The adhesive material can be epoxy resin or polyimide resin, etc., which can provide mechanical support and insulation protection after curing.

[0035] Finally, the carrier film on the first surface of the PCB multilayer board is peeled off. This peeling can be performed after the adhesive material has cured to remove the temporary support structure. Subsequently, a second filling process is applied to the target holes along the first surface of the PCB multilayer board, such as... Figure 10 As shown, pure adhesive is applied to the first surface of the PCB multilayer board 10; after the pure adhesive is pressed into the target hole, the final shape is as shown. Figure 11As shown. The second filling process can also be performed using methods such as dispensing, scraping, or spraying to fill the target hole with adhesive material to fill and cure the first end of the capacitor. Through these two filling processes, the capacitor can be fully fixed and encapsulated within the target hole, thereby improving its reliability and electrical performance.

[0036] This embodiment effectively solves the defects such as filling voids and insufficient glue that are prone to occur when traditional vertically embedding capacitors by using a step-by-step drilling, resin plugging, carrier film positioning, and multi-stage filling and curing method. It also reduces the risk of cracking or breakage of brittle capacitors due to mechanical and thermal stress during processing. This ensures precise and stable positioning and defect-free encapsulation of the capacitors within the PCB multilayer board, significantly improving the insulation performance, long-term reliability, and overall system integration of the embedded capacitors.

[0037] Example 2: Based on Embodiment 1, the present invention provides a second embodiment of a method for manufacturing a capacitor-embedded printed circuit board, to further describe the method for manufacturing a capacitor-embedded printed circuit board.

[0038] In some embodiments, in step S4, the target hole is first filled with adhesive along the second surface of the PCB multilayer board. Specifically, this includes: attaching pure adhesive to the first capacitor area on the second surface of the PCB multilayer board, wherein the first capacitor area is the area of ​​the target hole on the second surface of the PCB multilayer board and the projected area of ​​the first capacitor area is larger than the projected area of ​​the target hole; pressing the pure adhesive into the target hole using a vacuum fast pressing device so that the pure adhesive fills the gap between the second end of the capacitor and the target hole.

[0039] In this embodiment, the first capacitor region is a specific area on the second surface of the PCB multilayer board used to carry and guide the pure adhesive into the target hole. Its projected area is larger than the projected area of ​​the target hole, designed to ensure complete coverage of the target hole opening during adhesive application and to provide sufficient adhesive volume to accommodate adhesive flow and shrinkage during the filling process, while preventing adhesive overflow into non-target areas. The size and shape of the region are typically optimized based on the geometry of the target hole and the selected application process (such as screen printing, dispensing, etc.).

[0040] The term "pure adhesive" typically refers to a resin material with good flowability and curing properties, such as epoxy resin or modified epoxy resin. Pure adhesive, rather than filler-containing colloids, is chosen to ensure its permeability in minute gaps and avoid incomplete filling due to filler obstruction. The application of pure adhesive can be achieved through methods such as screen printing, stencil printing, or precision dispensing to precisely form a uniform adhesive layer in the first capacitor region.

[0041] Vacuum press equipment is a specialized device that integrates a vacuum environment, rapid pressurization, and temperature control. Pressing under vacuum effectively eliminates air that may be present in the target pores and the pure adhesive, thus preventing the formation of bubbles or voids after curing. Rapid pressurization helps to quickly force the adhesive into the gaps when its viscosity is low, ensuring a dense filling. The equipment typically includes a vacuum chamber, a heating platform, and an indenter for applying pressure.

[0042] Using a vacuum pressurization device, pure adhesive is forced into the target hole to fill the gap between the second end of the capacitor and the target hole. This is a crucial step in ensuring reliable capacitor embedding. In a vacuum environment, external pressure forcibly pushes the pure adhesive into all the tiny gaps between the second end of the capacitor and the target hole wall until it is completely filled. This method ensures that the capacitor receives stable mechanical support and good electrical insulation within the PCB multilayer board, laying a solid foundation for subsequent process steps.

[0043] The above technical solution involves attaching pure adhesive to the first capacitor area on the second surface of a PCB multilayer board and then using a vacuum press-fit device to press the adhesive into the target hole. This effectively avoids problems such as insufficient adhesive filling, voids, or air bubbles that may occur in traditional adhesive filling methods. The projected area of ​​the first capacitor area is larger than the projected area of ​​the target hole, ensuring sufficient adhesive quantity and good coverage. The application of the vacuum press-fit device allows for the uniform and dense filling of pure adhesive into the tiny gap between the second end of the capacitor and the target hole under vacuum conditions, significantly improving the fixing reliability of the capacitor, the stability of the electrical connection, and the yield of subsequent processes. This precise and efficient adhesive filling method provides a solid technological foundation for the embedded integration of capacitors.

[0044] In some embodiments, in step S5, a second filling process is performed on the target hole along the first surface of the PCB multilayer board. Specifically, this includes: attaching pure adhesive to the second capacitor area on the first surface of the PCB multilayer board, wherein the second capacitor area is the area of ​​the target hole on the first surface of the PCB multilayer board and the projected area of ​​the second capacitor area is larger than the projected area of ​​the target hole; pressing the pure adhesive into the target hole using a vacuum fast pressing device so that the pure adhesive fills the gap between the first end of the capacitor and the target hole.

[0045] In this embodiment, the second adhesive filling process is performed as in the first adhesive filling process. Through the above technical solution, when performing the second adhesive filling process on the first end of the capacitor, a pure adhesive with a projected area larger than the target hole is attached to the second capacitor area on the first surface of the PCB multilayer board. The pure adhesive is then pressed into the target hole using a vacuum high-pressure device. This effectively solves problems such as insufficient adhesive filling, residual air bubbles, or adhesive overflow that may occur during the adhesive filling process at the first end of the capacitor. The vacuum environment completely eliminates air from the target hole and the adhesive, preventing air bubble formation and ensuring a tight bond between the adhesive and the first end of the capacitor and the hole wall. Simultaneously, the rapid and uniform pressure provided by the high-pressure device allows the pure adhesive to flow quickly and fully fill the tiny gap between the first end of the capacitor and the target hole, forming a dense and defect-free encapsulation. This precisely controlled adhesive filling method not only ensures reliable fixation and excellent electrical insulation performance of the first end of the capacitor but also avoids potential quality problems in subsequent processing, thereby significantly improving the overall reliability and production yield of the capacitor-embedded printed circuit board.

[0046] In some implementations, see Figure 2 The process after step S5 also includes: S6, a connecting plate is pressed onto the first and / or second surfaces of a PCB multilayer board; S7, Laser processing is performed on the PCB multilayer board to create laser holes in the first capacitor area and / or the second capacitor area. S8 involves filling the laser holes with copper and performing a second outer layer circuit processing on the PCB multilayer board to complete the circuit fabrication for the capacitor components.

[0047] In steps S6-S8, the bonding connection plate refers to attaching additional layer structures to the surface of a PCB multilayer board with embedded capacitors. The connection plate typically refers to the additional layer structures used to construct the PCB multilayer board, which may include dielectric and conductive layers. For example, the connection plate may consist of at least one PP layer and at least one copper foil layer. The PP layer acts as a dielectric material, providing insulation and adhesion; the copper foil layer acts as a conductive layer for subsequent circuit fabrication. Through a thermoforming process, these connection plates are firmly bonded to the first and / or second surfaces of the PCB multilayer board with embedded capacitors, laying the foundation for subsequent circuit fabrication and electrical connections to the capacitors.

[0048] Subsequently, the PCB multilayer board undergoes laser processing to create laser-drilled holes in the first capacitor region and / or the second capacitor region. Laser processing refers to the technique of precisely drilling holes in the PCB multilayer board using a high-energy laser beam. After the capacitors are embedded and the connecting plate is laminated, a vertical conductive path needs to be established from the connecting plate to the capacitor electrodes. By laser processing the first capacitor region and / or the second capacitor region (i.e., the end projection area of ​​the capacitor), tiny laser holes can be precisely created. These laser holes will penetrate the connecting plate and part of the filler area, reaching the electrode surface of the capacitor, providing a channel for subsequent electrical connections.

[0049] Next, the laser-etched holes are filled with copper, and the PCB multilayer board undergoes a second outer layer circuit processing to complete the circuit fabrication of the capacitor. Copper filling refers to filling the laser-etched holes with conductive material (usually copper) to form a reliable conductive path. This can be achieved through copper plating or filling with conductive paste, ensuring good conductivity inside the laser-etched holes, thereby connecting the capacitor electrodes to the conductive layer on the connector board. After copper filling, a second outer layer circuit processing is performed, including but not limited to standard PCB manufacturing processes such as pattern transfer, etching, film removal, and solder mask application, to form a pre-defined circuit pattern on the connector board. The capacitor is then electrically connected to these outer layer circuits through the copper-filled laser-etched holes, ultimately completing the capacitor circuit fabrication and making it part of the functional circuitry of the PCB multilayer board.

[0050] The above technical solution effectively solves the electrical connection problem of embedded capacitors after they are embedded and cured. This is achieved through a pressing connection plate, laser processing, copper filling of the laser-cut holes, and a second outer layer circuit processing. Specifically, the pressing connection plate provides a new substrate for subsequent circuit fabrication; laser processing precisely creates tiny vias above the ends of the capacitors; copper filling ensures the conductivity of these micro-vias; and finally, the second outer layer circuit processing reliably connects the capacitors to other circuits on the PCB multilayer board. This allows the embedded capacitors to perform their electrical functions normally, improves the integration of the PCB multilayer board, and provides an effective manufacturing method for achieving high-density, high-performance electronic products.

[0051] In some implementations, after the first drilling process and / or after the second drilling process and / or after the laser treatment, the PCB multilayer board is further subjected to a de-adhesive treatment.

[0052] In this embodiment, adhesive removal refers to the removal of organic or inorganic residues from the surface, hole walls, or specific areas of the PCB multilayer board during manufacturing using physical or chemical methods. Specifically, after the first drilling process, drill shavings and resin dust may remain; after the second drilling process, in addition to drill shavings, resin overflow or residue may remain in the resin-filled areas; after laser processing, carbonized materials or molten residue formed by laser ablation will be generated. The purpose of adhesive removal is to ensure the cleanliness of these processed areas, providing a good surface condition for subsequent process steps. Common adhesive removal methods include, but are not limited to: chemical adhesive removal, such as using potassium permanganate solution or plasma treatment to oxidize and remove organic residues; and physical adhesive removal, such as high-pressure water washing, brushing, or ultrasonic cleaning to mechanically remove particulate impurities. These treatments can effectively remove various residues from the hole walls and board surface, ensuring the roughness and cleanliness of the hole walls, thereby providing a good foundation for subsequent processes such as copper plating and adhesive filling.

[0053] By employing the aforementioned technical solution, after the first drilling process and / or the second drilling process and / or the laser treatment, a desmearing process is performed on the PCB multilayer board. This effectively removes various residues such as drill chips, resin residues, and carbonized materials generated during drilling and laser treatment. This significantly improves the cleanliness and roughness of the PCB multilayer board's hole walls and surfaces, thereby ensuring the adhesion between the plating layer and the hole walls during subsequent copper plating and avoiding plating defects caused by residues. Simultaneously, clean hole walls facilitate the full filling and good adhesion of pure adhesive during subsequent filler treatment, reducing the risk of voids and delamination. Furthermore, removing residues helps improve the bonding strength of the laminated connectors and ensures the accuracy and reliability of the second outer layer circuitry treatment. Overall, the desmearing process effectively improves the manufacturing quality, reliability, and production yield of capacitor-embedded printed circuit boards, reducing the potential failure risk caused by process residues.

[0054] In some implementations, in step S3, the capacitor is vertically placed into the target hole. Specifically, "vertical placement" means that the axial direction of the capacitor is perpendicular to the plane of the PCB multilayer board, or parallel to the axial direction of the target hole. This placement method ensures the correct positioning and optimal posture of the capacitor within the target hole. Achieving vertical placement of the capacitor typically requires high-precision automated equipment, such as pick-and-place equipment equipped with a vision recognition system. This equipment can accurately identify the position of the capacitor and the target hole, and use a robotic arm to accurately insert the capacitor into the target hole in a direction perpendicular to the surface of the PCB multilayer board. Alternatively, specific clamps or guide structures can be designed to help maintain the capacitor's vertical position during placement, ensuring that its ends can stably and fully abut against the carrier film, laying a good foundation for subsequent glue filling and electrical connection.

[0055] By employing the aforementioned technical solution, vertically placing the capacitor into the target hole effectively prevents tilting or off-center placement during the process. This precise vertical placement ensures a uniform annular gap between the capacitor and the target hole wall, facilitating the uniform and sufficient filling of the gap between the second and first ends of the capacitor and the target hole during subsequent first and second adhesive filling processes. Simultaneously, vertical placement guarantees stable and reliable contact between the first end of the capacitor and the carrier film, ensuring a solid electrical contact foundation. This precise positioning and uniform gap significantly improve the reliability and consistency of capacitor embedding, reducing the risk of electrical performance instability or product failure due to improper placement, thereby enhancing the overall manufacturing yield and performance stability of the capacitor-embedded printed circuit board.

[0056] In some implementations, the length of the capacitor is less than the thickness of the PCB multilayer board. By designing or selecting the length of the capacitor to be less than the thickness of the PCB multilayer board, it can be ensured that neither end of the capacitor protrudes from the surface of the PCB multilayer board after it is embedded in the target hole. This effectively avoids interference between the capacitor and external structures during subsequent processes such as laminating the connecting board, thereby ensuring a smooth lamination of the connecting board, preventing structural defects in the PCB multilayer board due to localized stress concentration, and protecting the capacitor itself from mechanical damage. This significantly improves the manufacturing yield and reliability of capacitor-embedded printed circuit boards.

[0057] In some implementations, obtaining a multilayer PCB board in step S1 specifically includes: obtaining a core board through core board blanking, inner layer dry film processing, inner layer etching, and inner layer AOI processing; and pressing multiple core boards together to form a multilayer PCB board for crane use through browning, lamination, and grinding processes.

[0058] Specifically, core board cutting refers to the process of cutting large-sized copper-clad laminates (CCLs) into smaller core boards suitable for the production process. This process aims to provide dimensionally accurate, neat-edged base material for subsequent inner layer circuitry, ensuring positioning accuracy and material utilization during production. Precision cutting equipment is typically used to guarantee the flatness and dimensional tolerances of the cut surfaces.

[0059] Inner layer dry film processing refers to the process of attaching a layer of photosensitive dry film to the surface of the core board and transferring the pre-set inner layer circuit pattern onto the dry film through processes such as exposure and development. This process is a key step in forming the conductive circuits of the PCB inner layer, requiring the dry film to be attached smoothly without bubbles, and the exposure energy and development conditions to be precisely controlled to ensure the clarity and resolution of the circuit pattern.

[0060] Inner layer etching refers to the process of selectively removing copper foil not covered by dry film on the core board using a chemical etching solution, thereby forming the desired inner layer conductive circuit pattern. This process requires precise control of the etching solution concentration, temperature, and etching time to avoid over-etching or under-etching, ensuring that electrical properties such as line width and spacing meet design requirements.

[0061] Inner layer AOI (Automated Optical Inspection) refers to the process of using automated optical inspection equipment to scan and inspect the etched inner layer boards to detect defects such as short circuits, open circuits, residual copper, and gaps. This process can promptly identify and remove defective inner layer boards, effectively control product quality, prevent defects from flowing into subsequent processes, and reduce production costs.

[0062] Browning treatment refers to a chemical treatment of the inner layer board surface to form a rough oxide layer with good insulating properties, thereby increasing the adhesion between the interlayer resin and the copper foil. This treatment effectively prevents delamination of PCB multilayer boards during subsequent lamination, improving product reliability and heat resistance.

[0063] Lamination refers to the process of stacking multilayer processed core boards and dielectric layers (such as PP sheets) in a designed sequence and laminating them under high temperature and high pressure to solidify them into a single multilayer PCB board. This process requires precise interlayer alignment and strict temperature and pressure control to ensure a tight bond between layers, without gaps or delamination, forming a stable multilayer structure.

[0064] Cutting and grinding refers to the process of cutting and grinding the edges of a laminated multilayer PCB to achieve the final dimensional and edge quality requirements. This process aims to remove excess board edges and flatten them, providing standardized material for subsequent processes such as drilling and outer layer circuitry.

[0065] The above technical solution provides a detailed standard for the acquisition process of multilayer PCBs. From core board preparation to multilayer board lamination, each step undergoes meticulous processing and rigorous testing. Core board cutting ensures the dimensional accuracy of the base material; inner layer dry film treatment, inner layer etching, and inner layer AOI treatment guarantee the accuracy and defect-free nature of the inner layer circuit patterns; browning treatment enhances interlayer bonding and effectively prevents delamination; lamination ensures the tightness and stability of the multilayer structure; and grinding ultimately forms a PCB multilayer board with precise dimensions and smooth edges. This meticulous preparation process significantly improves the overall quality and reliability of the PCB multilayer board, providing a solid foundation for the precise embedding of capacitors and effectively avoiding embedding defects or product performance problems caused by board defects, thereby improving the yield and long-term stability of capacitor-embedded printed circuit boards.

[0066] Example 3: According to another aspect of the present invention, an apparatus for manufacturing a capacitor-embedded printed circuit board is provided, characterized in that the apparatus is used to perform the capacitor-embedded printed circuit board manufacturing method of Embodiment 1 or Embodiment 2.

[0067] This device is configured to perform key processes such as resin plugging, carrier film attachment, capacitor placement, and phased adhesive filling and curing. During operation, the device first controls the PCB multilayer board to complete the first drilling and copper plating process. Then, resin plugging is performed on the first drilled hole to form a resin-plugged area, and a second drilling is performed within this area to create the target hole. Further, the device attaches a carrier film to the first surface of the PCB multilayer board and guides the capacitor to be vertically placed into the target hole from the second surface, ensuring precise positioning of the first end of the capacitor against the carrier film. Based on this, the device performs a first adhesive filling process along the second surface of the PCB multilayer board to the target hole, using a vacuum press to press pure adhesive into the gap of the target hole to cure the second end of the capacitor. Subsequently, the carrier film on the first surface is removed, and a second adhesive filling process is performed along the first surface to the target hole, again using a vacuum press to fill the gap of the first end of the capacitor with pure adhesive to complete curing. By adopting a step-by-step glue filling strategy, the device effectively avoids filling voids and glue shortage defects caused by narrow and deep gaps. At the same time, through temporary support of the carrier film and vacuum pressure control, the mechanical stress and thermal mismatch risk of the capacitor components during the pressing and curing process are significantly reduced.

[0068] Through the above technical solution, the device ensures the stable vertical position of the capacitor in the target hole, realizes defect-free filling and precise stress control in the hole, thereby solving the core problems of decreased insulation performance and device breakage failure in traditional processes, and providing a reliable guarantee for the engineering application of high-density interconnect technology.

[0069] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. Similarly, for the sake of brevity and to aid in understanding one or more aspects of the invention, in the description of exemplary embodiments of the invention above, various features of the embodiments are sometimes grouped together in a single embodiment, figure, or description thereof. The claims, which follow the detailed description, are hereby expressly incorporated into the detailed description, wherein each claim itself is a separate embodiment of the invention.

[0070] Those skilled in the art will understand that the modules in the devices of the embodiments can be adaptively changed and placed in one or more devices different from those in the embodiments. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components, except that at least some of such features and / or processes or units are mutually exclusive.

[0071] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several systems, several of these systems may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A method for manufacturing a capacitor-embedded printed circuit board, characterized in that, The method includes: S1, Obtain the PCB multilayer board, perform the first drilling process on the PCB multilayer board to make the first drill hole, and perform copper plating process on the first drill hole. S2, perform resin plugging treatment on the first drilled hole to drive the resin plugged hole area, and perform a second drilling treatment in the resin plugged hole area to create the target hole. After completing the second drilling treatment, perform the first outer layer circuit treatment on the PCB multilayer board. S3, attach a carrier film to the first surface of the PCB multilayer board, and place a preset capacitor into the target hole along the second surface of the PCB multilayer board, with the first end of the capacitor abutting against the carrier film; S4, perform a first filling process on the target hole along the second surface of the PCB multilayer board to fill and cure the second end of the capacitor; S5, after peeling off the automotive film on the first surface of the PCB multilayer board, a second filling process is performed on the target hole along the first surface of the PCB multilayer board to fill and cure the first end of the capacitor.

2. The method for manufacturing a capacitor-embedded printed circuit board according to claim 1, characterized in that, In step S4, the target hole is first filled with adhesive along the second surface of the PCB multilayer board, specifically including: Pure adhesive is attached to the first capacitor area on the second surface of the PCB multilayer board, wherein the first capacitor area is the area of ​​the target hole on the second surface of the PCB multilayer board and the projected area of ​​the first capacitor area is larger than the projected area of ​​the target hole. Pure adhesive is pressed into the target hole using a vacuum fast pressing device, so that the pure adhesive fills the gap between the second end of the capacitor and the target hole.

3. The method for manufacturing a capacitor-embedded printed circuit board according to claim 2, characterized in that, In step S5, a second filling process is performed on the target hole along the first surface of the PCB multilayer board, specifically including: Pure adhesive is attached to the second capacitor region on the first surface of the PCB multilayer board, wherein the second capacitor region is the region of the target hole on the first surface of the PCB multilayer board and the projected area of ​​the second capacitor region is larger than the projected area of ​​the target hole. Pure adhesive is pressed into the target hole using a vacuum fast pressing device, so that the pure adhesive fills the gap between the first end of the capacitor and the target hole.

4. The method for manufacturing a capacitor-embedded printed circuit board according to claim 3, characterized in that, The process after step S5 also includes: S6, a connecting plate is pressed onto the first and / or second surfaces of the PCB multilayer board; S7, Laser processing is performed on the PCB multilayer board to create laser holes in the first capacitor area and / or the second capacitor area. S8, copper filling is performed on the laser holes, and a second outer layer circuit processing is performed on the PCB multilayer board to complete the circuit fabrication of the capacitor component.

5. The method for manufacturing a capacitor-embedded printed circuit board according to claim 4, characterized in that, In step S6, the connecting plate includes at least one PP layer and at least one copper foil layer.

6. The method for manufacturing a capacitor-embedded printed circuit board according to claim 4, characterized in that, The process also includes removing adhesive from the PCB multilayer board after the first drilling process and / or after the second drilling process and / or after the laser treatment.

7. The method for fabricating a capacitor-embedded printed circuit board according to claim 1, characterized in that, In step S3, the capacitor is vertically placed into the target hole.

8. The method for manufacturing a capacitor-embedded printed circuit board according to claim 7, characterized in that, The length of the capacitor is less than the thickness of the PCB multilayer board.

9. The method for manufacturing a capacitor-embedded printed circuit board according to claim 1, characterized in that, In step S1, the PCB multilayer board is obtained, specifically including: The core board is obtained through core board blanking, inner layer dry film processing, inner layer etching, and inner layer AOI processing. Multiple core boards are laminated into a multilayer PCB for cranes through browning, pressing, and grinding processes.

10. A capacitor-embedded printed circuit board fabrication apparatus, characterized in that, The apparatus is used to perform the capacitor-embedded printed circuit board manufacturing method according to any one of claims 1-9.

Images