TWM665435U - Printed Circuit Board - Google Patents

Abstract

The present invention provides a printed circuit board having at least one embedded redistribution line and at least one through hole penetrating the printed circuit board. The redistribution line is formed using a laser drilling process to ensure precise control of size and position. The surface roughness of the side and bottom of the redistribution line is maintained at less than one-quarter of the line width. The material of the redistribution line and the through hole includes copper or a conductive gel containing copper. The printed circuit board material is selected from non-woven fabrics, polymer materials, glass fibers, glass, ceramics and silicon. The present invention also includes a method for forming such a printed circuit board, which involves providing a printed circuit board substrate, forming redistribution lines and through holes using laser drilling, cleaning the substrate, and filling the redistribution lines and through holes with conductive materials. The method allows the use of electroless plating or conductive glue coating technology.

Description

Printed circuit board

This novel invention mainly relates to the field of printed circuit boards, and more specifically, to a method and structure for forming redistribution lines and through holes in printed circuit boards using advanced laser drilling and filling techniques.

Printed circuit boards are basic components in various electronic devices, providing mechanical support and electrical connections for various electronic components. With the growth of miniaturization and high performance requirements of electronic devices, the demand for printed circuit boards with finer lines and smaller through holes has increased significantly. Meeting these requirements is a challenge for traditional printed circuit board manufacturing methods. ,additive,semi-additive,and modified semi-additive

Traditional printed circuit board forming methods generally include subtractive process, additive process, semi-additive process, and modified semi-additive process. These methods often face limitations in achieving fine line widths and maintaining stability at scales less than 10 microns. For example, the subtractive process involves etching away unwanted copper from a copper-clad substrate, which encounters significant challenges in accuracy and side etching effects when the line width is reduced to very fine scales.

Semi-additive and modified semi-additive processes are widely used in the industry to produce printed circuit boards with high-density interconnects. These methods generally involve coating a thin layer of copper on a substrate, followed by patterning and electroplating to form the desired circuits. Although semi-additive and modified semi-additive processes offer better precision and lower costs than 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 may negatively affect the electrical performance of the printed circuit board due to side etching effects.

To address these challenges, advanced methods involving laser drilling and filling techniques have been developed. Laser drilling allows for precise formation of redistribution layer grooves and vias, which are critical for forming high-density interconnects with fine line widths and improved electrical performance. However, existing methods still face limitations in achieving the required accuracy and cost-effectiveness, especially for low-volume and custom printed circuit board production.

In order to solve the above problems, the purpose of this invention is to provide a printed circuit board and a manufacturing method thereof.

The novel printed circuit board includes at least one redistribution line embedded in the printed circuit board and at least one conductive through hole penetrating the printed circuit board. The printed circuit board is manufactured by utilizing advanced laser drilling and optimized filling technology to achieve fine line width and improved electrical performance, thereby solving the limitations of traditional manufacturing methods.

The redistribution lines within the printed circuit board are formed using a laser drilling process, ensuring precise control of the size and position of the redistribution lines. This method allows the formation of redistribution lines with a surface roughness of less than one-quarter of the line width on the side and bottom, which can enhance the stability and reliability of electrical connections. The materials used for the redistribution lines and through holes include copper or copper-containing conductive colloids. To provide the required electrical conductivity and mechanical stability.

The printed circuit board material is selected from non-woven fabrics, polymer materials, glass fibers, glass, ceramics, and silicon. The specific polymer material can be selected from the group consisting of polyethylene terephthalate (PET), polyimide (PI), polymethyl methacrylate (PMMA), polyetheretherketone (PEEK), epoxy resin, Ajinomoto laminate film (ABF), triazine benzoxylindole resin (TBF), bismaleimide triazine (BT), and polytetrafluoroethylene (PTFE). Such selection ensures that the printed circuit board can meet various application requirements, including those requiring high thermal stability and mechanical strength.

The novel invention also includes a method for forming a printed circuit board, the method comprising the following steps. First, a printed circuit board substrate is provided. Next, at least one redistribution wiring pattern groove embedded in the printed circuit board substrate is formed. Then, at least one through hole is formed in the printed circuit board substrate. Next, the substrate is cleaned. Thereafter, a conductive material is formed in the redistribution wiring pattern groove and the through hole, thereby forming a redistribution wiring and a conductive through hole. The redistribution wiring pattern groove is formed using a laser drilling process, which ensures high precision and reduces the risk of defects associated with traditional etching methods. The surface roughness of the side and bottom of the redistribution wiring pattern groove is maintained at less than one-quarter of the line width, further improving the electrical performance of the printed circuit board.

The conductive material applied to the redistribution pattern grooves and through holes includes copper or a conductive gel containing copper. The material selection is determined by the required conductivity and durability. The novel method also allows the use of an electroless plating process or a conductive gel coating process to form the redistribution lines, providing flexibility in the manufacturing process and enabling cost-effective production of high-density interconnects.

In summary, this novel method 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 technology, this novel method provides significant improvements in accuracy, cost-effectiveness, and production speed, meeting the ever-changing needs of the electronics industry.

In order to make the above features and advantages of the new model more obvious and easy to understand, the following is a detailed description of the preferred embodiment with the attached drawings.

100:Printed circuit board

110: Printed circuit board substrate

120: Rerouting

120': Re-layout wiring pattern groove

130: Conductive via

130': Through hole

140: Conductive materials

142': Thin copper layer

S110~S150, S153~S159, S162, S164: Flowchart steps

FIG1 shows a structural diagram of one embodiment of the printed circuit board of the present invention.

FIG2 shows a flow chart of one embodiment of the manufacturing method of the new printed circuit board.

Figures 3A to 3C are schematic diagrams corresponding to each step of Figure 1.

FIG4 is a flow chart of an embodiment of applying the electroless plating process to redistribution of wiring and conductive vias.

Figures 5A and 5B are schematic diagrams corresponding to certain steps of Figure 4.

Figure 6 shows the flow chart of the conductive glue coating process.

The present invention provides a printed circuit board and a manufacturing method thereof with high precision, high efficiency, and high cost-effectiveness in manufacturing. The present invention adopts advanced laser drilling and optimized filling technology to form redistribution wiring and conductive through holes to solve the limitations of the manufacturing method of traditional printed circuit boards. The following is a detailed description of the embodiments of the printed circuit board and its manufacturing process involved in the present invention.

Please refer to FIG. 1, which shows a structural diagram of one embodiment of the printed circuit board of the present invention. The printed circuit board 100 of the present invention includes at least one redistribution line 120 embedded in the printed circuit board 100 and at least one conductive via 130 passing through the printed circuit board 100. The redistribution line 120 can redistribute electrical signals in the printed circuit board 100, allowing high-density interconnection and enhanced electrical performance. The conductive via 130 is a line that provides vertical electrical connection between different circuit layers in the printed circuit board 100.

The redistribution line 120 is formed by laser drilling during the manufacturing process of the printed circuit board 100 (to be described in detail later). Laser drilling can accurately control the size and position of the redistribution line 120. This method ensures that the surface roughness of the side and bottom of the redistribution line 120 is less than one-quarter of the line width. Low surface roughness is important for the stability and reliability of electrical connections because it can reduce resistance and reduce the possibility of defects.

The material used for the redistribution line 120 and the conductive via 130 includes copper or a conductive colloid containing copper to provide the required conductivity and mechanical stability. The manufacturing method of the above-mentioned printed circuit board 100 will be introduced below.

Please refer to FIG. 2 and FIG. 3A to FIG. 3C. FIG. 2 is a flow chart of one embodiment of the manufacturing method of the novel printed circuit board, and FIG. 3A to FIG. 3C are schematic diagrams corresponding to each step of FIG. 1. First, please refer to step S110. The manufacturing process of the printed circuit board begins with providing a printed circuit board substrate 110. The printed circuit board substrate 110 can be made of many different materials, such as non-woven fabrics, polyimide, polymer materials, glass fibers, glass, ceramics, and silicon, depending on the application requirements. The above-mentioned polymer materials are, for example, polyethylene terephthalate, polyimide, polymethyl methacrylate, polyetheretherketone, epoxy resin, Ajinomoto laminate film, triazine benzoxyheteropolymer resin, bismaleimide triazine and polytetrafluoroethylene.

Thereafter, please refer to step S120 to form at least one redistribution wiring pattern groove 120' in the printed circuit board substrate 110. In the present embodiment, the redistribution wiring pattern groove 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 drill hole position. The laser is then activated, and the beam is directed onto the printed circuit board substrate 110, rapidly heating and vaporizing the material. The removed material is removed from the drill hole, leaving behind a clean, well-defined redistribution wiring pattern groove 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 redistribution wiring pattern groove 120' is less than one-quarter of the line width. Compared with traditional etching methods, high-precision laser drilling equipment has several advantages, including obtaining the required line width and groove depth by controlling the energy and scanning speed of the laser, and having higher precision, reducing defects around the groove and the bottom, improving flatness, and being able to form complex redistribution wiring patterns without the need for thick film photoresist.

After forming the redistribution wiring pattern groove 120', step S130 is performed to form at least one through hole 130' in the printed circuit board substrate 110 using the same laser drilling process, and the through hole 130' penetrates the entire printed circuit board substrate 110. In addition, after forming the redistribution wiring pattern groove 120' and the through hole 130', the printed circuit board substrate 110 will undergo a cleaning process (such as step S140) to remove any debris, contaminants, and residues that may be introduced during the laser drilling process to ensure the adhesion and conductivity of the subsequent filling of the 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 detergents to dissolve and remove contaminants from the substrate surface, while plasma cleaning uses plasma to etch away 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.

Afterwards, step S150 is performed to fill the conductive material 140 into the redistribution wiring pattern groove 120' and the through hole 130' to form the redistribution wiring 120 and the conductive through hole 130. These conductive materials 140 may include copper or a conductive gel containing copper. The filling process may be performed using an electroless plating process or a conductive gel coating process, and the electroless plating process or the conductive gel coating process will be introduced below.

Please refer to FIG. 4 and FIG. 5A ~ FIG. 5B. FIG. 4 is a flow chart of an embodiment of applying the electroless plating process to the redistribution line 120 and the conductive through hole 130. FIG. 5A ~ FIG. 5B are schematic diagrams corresponding to certain steps of FIG. 4. First, please refer to step S153 and FIG. 5A, and use surface catalysis to deposit a thin copper layer 142' on the surface of the redistribution line pattern groove 120' and the through hole 130' (as shown in FIG. 3B). Surface catalysis refers to treating the printed circuit board substrate 110 with a catalyst to enhance the deposition of copper. Afterwards, please refer to step S155 to start the electroless plating process. In this embodiment, the electroless plating process is initiated by immersing the printed circuit board substrate 110 in a plating solution containing a copper salt, a reducing agent, and various additives for controlling the deposition rate and quality. Then, referring to step S157 and FIG. 5B , a chemical reaction occurs, and a copper layer is uniformly deposited on the redistribution wiring pattern grooves 120 'and the through holes 130 'to form the redistribution wiring 120 and the conductive through holes 130. Thereafter, referring to step S159, the printed circuit board substrate 110 formed with the redistribution wiring 120 and the conductive through holes 130 is subjected to a rinsing and annealing process to remove any residual chemical substances. 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 on non-conductive surfaces.

In addition, the redistribution lines 120 and the conductive vias 130 can also be formed using a conductive glue coating process. Next, please refer to FIG. 6, which is a flow chart of the conductive glue coating process. First, as shown in step S162, a conductive glue containing conductive particles is coated on the redistribution line pattern grooves 120' and the through holes 130'. This step S162 can be achieved using a rotary coating method, or a scraper pattern method or other known methods of filling conductive glue into grooves (please confirm with the newcomer). Then, as shown in step S164, a high-temperature heat treatment is performed to volatilize the organic solvent of the conductive glue to form a solid conductive layer, that is, to form the redistribution lines 120 and the conductive vias 130. In step S164, the high temperature heat treatment temperature is between 150℃ and 300℃, and the time is between 30 and 180 minutes.

The printed circuit board and its manufacturing method described in this novel invention have several significant advantages over traditional printed circuit board manufacturing technology. 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. The surface roughness of the re-routing circuit is controlled to less than one-quarter of the line width, further improving the stability and reliability of the electrical connection.

The new technology also provides flexibility in the choice of materials for redistribution and PCB substrates, allowing PCBs to be customized to specific application requirements. Filling the redistribution pattern grooves and through-holes using electroless plating or conductive adhesive coating processes ensures excellent conductivity and adhesion, enhancing the overall durability and performance of the PCB.

Furthermore, the method for manufacturing printed circuit boards described in the present invention is cost-effective and efficient, and is suitable for both mass production and small batch custom orders. By reducing the complexity of the manufacturing process and minimizing the required steps, the method shortens production time and reduces costs, bringing significant benefits to manufacturers and end users.

In summary, this new product 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 technology, this new product meets the evolving needs of the electronics industry and provides a reliable method for producing high-quality printed circuit boards.

Although the present invention has been disclosed as above with the preferred embodiment, it is not intended to limit the present invention. Anyone with common knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined in the attached patent application.

100:Printed circuit board

120: Rerouting

130: Conductive via

Claims (6)

A printed circuit board, comprising: at least one redistribution wiring pattern embedded in the printed circuit board; and at least one conductive through hole penetrating the printed circuit board. A printed circuit board as described in claim 1, wherein the redistribution wiring pattern is formed using a laser drilling process. A printed circuit board as described in claim 1, wherein the surface roughness of the side and bottom of the redistribution line is less than one quarter of the line width. A printed circuit board as described in claim 1, wherein the material filling the redistribution line and the conductive through hole includes copper or a conductive gel containing copper. A printed circuit board as described in claim 1, wherein the material of the printed circuit board is selected from the group consisting of non-woven fabrics, polyimide, polymer materials, glass fibers, glass, ceramics and silicon. A printed circuit board as described in claim 1, wherein the redistribution line is formed by an electroless plating process or a conductive glue coating process.

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