Printed circuit board
By using laser drilling and optimized filling technology to form high-precision redistribution lines and conductive vias, the problems of fine linewidth and high-density interconnection in traditional printed circuit board manufacturing have been solved, enabling efficient and low-cost printed circuit board production.
Patent Information
- Application Number
- CN202422236261.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Priority Date
- 2024-07-08
- Filing Date
- 2024-09-12
- Publication Date
- 2025-12-19
- Estimated Expiration
- 2034-09-12
AI Technical Summary
Traditional printed circuit board manufacturing methods struggle to achieve fine linewidths and high-density interconnects, and are limited in terms of precision and cost-effectiveness, especially in small-batch and custom production.
Advanced laser drilling technology is used to form the redistributed circuitry and conductive vias. Optimized filling techniques are employed using copper or copper-containing conductive colloids, combined with electroless plating or conductive adhesive coating processes, to ensure high precision and conductivity of the redistributed circuitry.
It achieves finer linewidth and improved electrical performance, enhances the stability and reliability of electrical connections, reduces production costs and complexity, and is suitable for both large-scale and small-batch production.
Smart Images
Figure CN223694070U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present utility model relates to the field of printed circuit boards, more specifically, to a method and structure for forming redistribution lines and vias in printed circuit boards using advanced laser drilling and filling techniques. BACKGROUND
[0002] Printed circuit boards are the basic components in various electronic devices, providing mechanical support and electrical connections for various electronic components. With the increasing demand for miniaturization and high performance of electronic devices, there is a significant increase in demand for printed circuit boards with finer lines and smaller vias. To meet these requirements, it is a challenge for traditional printed circuit board manufacturing methods.
[0003] Traditional printed circuit board forming methods generally include subtractive processes, additive processes, semi-additive processes, and modified semi-additive processes. These methods often face limitations in achieving fine line widths and maintaining stability on the order of less than 10 microns. For example, the subtractive process involves etching unwanted copper from a copper-clad substrate, which encounters significant challenges in precision and side etching effects when the line width is reduced to very fine scales.
[0004] Semi-additive and modified semi-additive processes are widely used in the industry to produce high-density interconnect printed circuit boards. These methods generally include coating a thin layer of copper on the substrate, then patterning and electroplating to form the required circuit. Although semi-additive and modified semi-additive processes provide better precision and lower cost compared to additive processes, they still require complex steps such as thick film photoresist and flash etching to define line widths. These additional steps increase the overall complexity and cost of the manufacturing process and can negatively affect the electrical performance of the printed circuit board due to side etching effects.
[0005] To address these challenges, advanced methods involving laser drilling and filling techniques have been developed. Laser drilling allows for the precise formation of redistribution layer groove patterns and vias, which are essential for forming high-density interconnects with fine line widths and improved electrical performance. However, existing methods still face limitations in achieving the required precision and cost-effectiveness, especially for small batch and custom printed circuit board production. SUMMARY
[0006] To solve the above problems, the purpose of the present utility model is to provide a printed circuit board and a manufacturing method thereof.
[0007] The printed circuit board includes at least one re-routed trace embedded within the printed circuit board and at least one conductive via extending through the printed circuit board. The printed circuit board is manufactured using advanced laser drilling and optimized filling techniques to achieve fine line widths and improved electrical performance, thereby overcoming the limitations of conventional manufacturing methods.
[0008] The re-routed trace within the printed circuit board is formed using a laser drilling process to ensure precise control over the size and location of the re-routed trace. This method allows the formation of a re-routed trace with a side and bottom surface roughness less than one quarter of the line width, which enhances the stability and reliability of the electrical connection. The materials used for the re-routed trace and via include copper or copper-containing conductive pastes to provide the required electrical conductivity and mechanical stability.
[0009] The printed circuit board material is selected from the group consisting of non-woven fabric, polymeric material, glass fiber, glass, ceramic, and silicon. Specific polymeric materials can be selected from the group consisting of polyethylene terephthalate (PET), polyimide (PI), polymethyl methacrylate (PMMA), polyether ether ketone (PEEK), epoxy, ABF, triazine benzoxazole resin (TBF), bismaleimide triazine (BT), and polytetrafluoroethylene (PTFE). This selection ensures that the printed circuit board can meet the requirements of various applications, including those requiring high thermal stability and mechanical strength.
[0010] The utility model also includes a method of forming a printed circuit board, which comprises the following steps. First, a printed circuit board substrate is provided. Next, at least one re-routed trace pattern recess is formed embedded within the printed circuit board substrate. Then, at least one via is formed within the printed circuit board substrate. The substrate is then cleaned. After that, conductive material is formed in the re-routed trace pattern recess and the via, thereby forming the re-routed trace and the conductive via. The re-routed trace pattern recess is formed using a laser drilling process, which ensures high precision and reduces the risk of defects associated with conventional etching methods. The side and bottom surface roughness of the re-routed trace pattern recess is maintained at less than one quarter of the line width, further improving the electrical performance of the printed circuit board.
[0011] The conductive material applied to the re-routed trace pattern recess and the via includes copper or copper-containing conductive pastes. The material selection is determined based on the required electrical conductivity and durability. The method of the utility model also allows the use of electroless plating processes or conductive paste coating processes to form the re-routed trace, providing flexibility in the manufacturing process and enabling cost-effective production of high-density interconnects.
[0012] In summary, the present application provides a comprehensive and advanced method for manufacturing high-density printed circuit boards with fine line widths and improved electrical performance. By utilizing laser drilling technology and optimized filling techniques, the present application provides significant improvements in precision, cost-effectiveness, and production speed, meeting the changing demands of the electronics industry.
[0013] To make the above features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, together with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS
[0014] Figure 1 The structure diagram of one embodiment of the printed circuit board of the present application is shown.
[0015] Figure 2 The flowchart of one embodiment of the manufacturing method of the printed circuit board of the present application is shown.
[0016] Figure 3A The schematic diagram corresponding to step S110 of Figure 2 is shown.
[0017] Figure 3B The schematic diagram corresponding to steps S120-S140 of Figure 2 is shown.
[0018] Figure 3C The schematic diagram corresponding to step S150 of Figure 2 is shown.
[0019] Figure 4 The flowchart of the embodiment of the electroless plating process applied to the heavy wiring and conductive via is shown.
[0020] Figure 5A The schematic diagram corresponding to step S153 of Figure 4 is shown.
[0021] Figure 5B The schematic diagram corresponding to step S157 of Figure 4 is shown.
[0022] Figure 6 The flowchart of the conductive adhesive coating process is shown. DETAILED DESCRIPTION
[0023] The present application provides a printed circuit board and a manufacturing method thereof with high precision, high efficiency, and high cost-effectiveness in manufacturing. By adopting advanced laser drilling and optimized filling techniques, the present application forms heavy wiring and conductive via to solve the limitations of traditional printed circuit board manufacturing methods. The embodiments of the printed circuit board and its process involved in the present application are described in detail below.
[0024] Referring to Figure 1 , Figure 1 The structure diagram is shown as one embodiment of the printed circuit board of the present application. The printed circuit board 100 comprises at least one re-routed line 120 embedded in the printed circuit board 100 and at least one conductive via 130 penetrating the printed circuit board 100. The re-routed line 120 is capable of re-distributing electrical signals within the printed circuit board 100, allowing high-density interconnection and enhanced electrical performance. The conductive via 130 is a line providing vertical electrical connection between different line layers in the printed circuit board 100.
[0025] The re-routed line 120 is formed by laser drilling during the manufacturing process of the printed circuit board 100 (to be described later), which is capable of precisely controlling the size and position of the re-routed line 120. This method ensures that the surface roughness of the side and bottom of the re-routed line 120 is less than one-fourth of the line width. Low surface roughness is important for the stability and reliability of electrical connection, as it can reduce resistance and lower the possibility of defects.
[0026] The material used for the re-routed line 120 and the conductive via 130 includes copper or copper-containing conductive paste to provide the required electrical conductivity and mechanical stability. Below, the manufacturing method of the printed circuit board 100 described above will be introduced.
[0027] Referring to Figure 2 and Figures 3A-3C , Figure 2 The flow chart is shown as one embodiment of the manufacturing method of the printed circuit board of the present application, Figures 3A-3C The schematic diagram is shown corresponding to each step of Figure 2 . First, referring to step S110, the manufacturing process of the printed circuit board begins with providing a printed circuit board substrate 110, which can be made of many different materials, such as non-woven fabric, polyimide, polymer material, glass fiber, glass, ceramic and silicon, depending on the application requirements. The polymer material mentioned above is, for example, polyethylene terephthalate, polyimide, polymethyl methacrylate, polyether ether ketone, epoxy resin, Ajinomoto laminated film, triazine benzoxazole resin, bismaleimide triazine and polytetrafluoroethylene.
[0028] After that, please refer to step S120, at least one heavy routing pattern recess 120' is formed in the printed circuit board substrate 110. In this embodiment, the heavy routing pattern recess 120' is formed using a laser drilling process. At the beginning of the laser drilling process, the printed circuit board substrate 110 can be placed on a movable platform (not shown), which allows the laser beam to be precisely aligned with the desired drilling location. Then the laser is activated, and the beam is directed onto the circuit board substrate 110, rapidly heating and vaporizing the material. The removed material is removed from the drill hole, leaving a clean, well-defined heavy routing pattern recess 120'. This step S120 allows the formation of fine lines with precise dimensions, ensuring that the surface roughness of the sides and bottom of the heavy routing pattern recess 120' is less than one-fourth of the line width. Compared with traditional etching methods, high-precision laser drilling equipment has several advantages, including obtaining the desired line width and recess depth by controlling the energy and scanning speed of the laser, and having higher precision, reducing defects on the periphery and bottom of the recess, improving flatness, and being able to form complex heavy routing patterns without the need for thick film resist manufacturing.
[0029] After forming the heavy routing pattern recess 120', step S130 is performed to form at least one via 130' in the printed circuit board substrate 110 using the same laser drilling process, the via 130' penetrating through the entire printed circuit board substrate 110. In addition, after forming the heavy routing pattern recess 120' and the via 130', the printed circuit board substrate 110 undergoes a cleaning process (such as step S140) to remove any debris, contaminants, and residues that may have been introduced during the laser drilling process, to ensure the adhesion and conductivity of the subsequent conductive material 140. Step S140 can use various appropriate cleaning methods, including chemical cleaning, plasma cleaning, and ultrasonic cleaning. Chemical cleaning involves the use of solvents and cleaning agents to dissolve and remove contaminants on the surface of the substrate, while plasma cleaning uses plasma to etch and remove organic residues and oxides. Ultrasonic cleaning uses high-frequency sound waves to agitate the cleaning solution, effectively removing particles and contaminants from the printed circuit board substrate 110.
[0030] After that, step S150 is performed to fill the heavy routing pattern recess 120' and the via 130' with conductive material 140 to form the heavy routing 120 and the conductive via 130. These conductive materials 140 can include copper or copper-containing conductive paste. The filling process can be carried out using an electroless plating process or a conductive paste coating process, which will be introduced separately below.
[0031] Please refer to Figure 4 With Figures 5A-5B , Figure 4 the flowchart of the embodiment of applying the electroless plating process to the heavy routing 120 and the conductive via 130, Figures 5A-5Billustrated as corresponding to Figure 4 some steps of the method. First, refer to step S153 and Figure 5A , a thin layer of copper 142' is deposited on the surface of the re-routed pattern recesses 120' and vias 130' (as shown in Figure 3B ) using surface catalysis. Surface catalysis refers to treating the printed circuit board substrate 110 with a catalyst to enhance copper deposition. Next, refer to step S155, an electroless plating process is initiated. In this embodiment, the electroless plating process is initiated by immersing the printed circuit board substrate 110 in an electroless plating solution containing copper salts, reducing agents, and various additives to control the rate and quality of deposition. Next, refer to step S157 and Figure 5B , a chemical reaction occurs to uniformly deposit a layer of copper on the re-routed pattern recesses 120' and vias 130' to form the re-routed lines 120 and conductive vias 130. Next, refer to step S159, the printed circuit board substrate 110 with the re-routed lines 120 and conductive vias 130 is rinsed and annealed to remove any residual chemicals. Advantages of the electroless plating process include excellent uniformity of the deposited layer, strong adhesion to the printed circuit board substrate 110, and the ability to coat non-conductive surfaces.
[0032] In addition, the re-routed lines 120 and conductive vias 130 can also be formed using a conductive paste coating process. Next, refer to Figure 6 , Figure 6 , which is a flowchart of the conductive paste coating process. First, as shown in step S162, a conductive paste containing conductive particles is coated on the re-routed pattern recesses 120' and vias 130'. This step S162 can be achieved using a spin coating method, or a doctor blade method or other conventional method of filling the recesses with conductive paste. Then, as shown in step S164, a high temperature heat treatment is performed to evaporate the organic solvent of the conductive paste to form a solid conductive layer, that is, to form the re-routed lines 120 and conductive vias 130. In step S164, the high temperature heat treatment is performed at a temperature of 150°C to 300°C for a time of 30 to 180 minutes.
[0033] The printed circuit board and its manufacturing method described in the present application have many significant advantages over traditional printed circuit board manufacturing techniques. The use of laser drilling technology ensures high precision and reduces the risk of defects, thereby producing a printed circuit board with fine line width and enhanced electrical performance. Controlling the surface roughness of the re-routed lines to less than one-fourth of the line width further improves the stability and reliability of the electrical connection.
[0034] The present application also provides flexibility in the selection of materials for the redistribution layer and the printed circuit board substrate, allowing the printed circuit board to be customized for specific application requirements. The use of electroless plating or conductive adhesive coating processes to fill the redistribution layer patterned recesses and vias ensures excellent conductivity and adhesion, enhancing the overall durability and performance of the printed circuit board.
[0035] Furthermore, the manufacturing method of the printed circuit board described in the present application is cost-effective and efficient, suitable for large-scale production and small-batch custom orders. By reducing the complexity of the manufacturing process and minimizing the required steps, the method shortens the production time and reduces the cost, bringing significant benefits to manufacturers and end users.
[0036] In summary, the present application provides a comprehensive and advanced solution for manufacturing high-density printed circuit boards with fine line widths, improved electrical performance, and cost-effectiveness. By utilizing advanced laser drilling technology and optimized filling techniques, the present application meets the evolving needs of the electronics industry and provides a reliable method for producing high-quality printed circuit boards.
[0037] As explained above, the present application is not intended to limit the scope of the patent rights claimed. Any changes or modifications made by those skilled in the art without departing from the spirit or scope of the present patent, as well as equivalent changes or designs completed under the disclosed spirit, should be included in the claims of the present application.
Claims
1. A printed circuit board, characterized by, Comprising: at least one heavy wiring pattern embedded in said printed circuit board; and at least one conductive via through said printed circuit board; wherein the side and bottom surfaces of the heavy wiring pattern have a surface roughness less than one quarter of the line width.