Printed circuit board and method of manufacturing the same

Abstract

The embodiment of the present application provides a printed circuit board, comprising: a core plate and a solidification layer attached to the core plate; the core plate comprises a dielectric layer, a pattern part and a barrier part formed by etching a copper layer laid on the dielectric layer, a functional area is arranged on the dielectric layer and adjacent to the barrier part, the barrier part is located between the functional area and the pattern part, and a gap is left between the barrier part and the pattern part; and the solidification layer covers the pattern part, the barrier part and the functional area on the dielectric layer and fills the gap. In addition, the embodiment of the present application also provides a manufacturing method of the printed circuit board. The printed circuit board and the manufacturing method thereof provided by the embodiment of the present application avoid the resin material flowing into the functional area and reduce the manufacturing cost of the printed circuit board, since the barrier part is formed by etching the copper layer of the core plate itself without adding other materials such as shims and cover films.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of circuit technology, and in particular to a printed circuit board and a method for manufacturing the same. Background Art

[0002] With the rapid advancement of science and technology, the high-speed serial signal rate of printed circuit boards (PCBs) has gradually increased to 56Gbps. PCB design is breaking through the inherent limitations of copper resin and attempting to employ cavity area technology to improve PCB performance and reduce PCB losses. During the manufacturing process of PCBs utilizing cavity area technology, functional areas are first formed on the core board, and then the prepreg and core board are laminated together. Because the prepreg, after being heated and softened during the lamination process, contains a fluid resin material, to prevent the resin material from flowing into the functional area, a gasket or cover film is placed around the functional area before the prepreg and core board are laminated together to prevent the resin material from flowing into the functional area.

[0003] However, when a gasket or cover film is provided to prevent the resin material from flowing into the functional area during the lamination process, other materials (gasket or cover film) are added during the manufacturing process of the printed circuit board, thereby increasing the manufacturing cost of the printed circuit board. Summary of the Invention

[0004] The main purpose of the embodiments of the present application is to propose a printed circuit board and a manufacturing method thereof, which can avoid the resin material from flowing into the functional area during the lamination process of the semi-cured sheet and the core board without adding other materials (gasket or covering film), thereby reducing the manufacturing cost of the printed circuit board.

[0005] To achieve the above-mentioned purpose, an embodiment of the present application provides a printed circuit board, comprising: a core board and a solidified layer adhered to the core board; the core board includes a dielectric layer, and a pattern portion and a retaining wall portion formed by etching a copper layer laid on the dielectric layer, a functional area adjacent to the retaining wall portion is provided on the dielectric layer, the retaining wall portion is located between the functional area and the pattern portion, and a gap is left between the retaining wall portion and the pattern portion; the solidified layer covers the pattern portion, the retaining wall portion and the functional area located on the dielectric layer and fills the gap.

[0006] To achieve the above-mentioned purpose, an embodiment of the present application also provides a method for manufacturing a printed circuit board, comprising: providing a core board including a dielectric layer and a copper layer laid on the dielectric layer; etching the copper layer to form a pattern portion, a retaining wall portion and a functional area located on the dielectric layer, wherein the functional area is adjacent to the retaining wall portion, the retaining wall portion is located between the functional area and the pattern portion, and a gap is left between the retaining wall portion and the pattern portion; providing a semi-cured sheet for bonding to the core board; slotting the semi-cured sheet at a position corresponding to the functional area; pressing the core board and the semi-cured sheet so that the semi-cured sheet covers the pattern portion, the retaining wall portion and the functional area located on the dielectric layer, and allowing part of the material of the semi-cured sheet to fill the gap under pressure; and curing the semi-cured sheet to form a cured layer.

[0007] The printed circuit board and the manufacturing method thereof proposed in the present application form a pattern portion, a retaining wall portion and a functional area on the dielectric layer when etching the copper layer. The retaining wall portion is located between the functional area and the pattern portion, and a gap is left between the retaining wall portion and the pattern portion, thereby ensuring that during the process of pressing the semi-cured sheet and the core board, the retaining wall portion is used to prevent the fluid resin material contained in the heated and softened semi-cured sheet from flowing into the functional area, so that the resin material can only flow in the gap. Since the retaining wall portion is etched from the copper layer of the core board itself, there is no need to add other materials such as gaskets and covering films, thereby preventing the resin material from flowing into the functional area while reducing the manufacturing cost of the printed circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic diagram of the partial structure of a printed circuit board provided in the first embodiment of the present invention;

[0009] Figure 2 This is a schematic diagram of the partial structure of a printed circuit board provided in the second embodiment of the present invention;

[0010] Figure 3 1 is a flow chart of a method for manufacturing a printed circuit board according to a third embodiment of the present invention;

[0011] Figure 4 This is a graph showing experimental data on the change in loss when a gasket or cover film is provided on a printed circuit board compared to etching a retaining wall portion on a copper layer, as provided in Example 3 of the present invention;

[0012] Figure 5 It is a flow chart of a method for manufacturing a printed circuit board provided in the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, each embodiment of the present application will be described in detail below with reference to the accompanying drawings. However, it will be understood by those skilled in the art that in each embodiment of the present application, many technical details are proposed to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can be implemented. The division of the following embodiments is for convenience of description and should not constitute any limitation on the specific implementation of the present application. The various embodiments can be combined and referenced with each other under the premise of no contradiction.

[0014] Embodiment 1 of the present invention relates to a printed circuit board. When etching a copper layer, a pattern portion, a retaining wall portion and a functional area are formed on a dielectric layer. The retaining wall portion is located between the functional area and the pattern portion, and a gap is left between the retaining wall portion and the pattern portion. This ensures that during the process of pressing a prepreg and a core board together, the retaining wall portion is used to prevent the fluid resin material contained in the heated and softened prepreg from flowing into the functional area, so that the resin material can only flow in the gap. Since the retaining wall portion is etched from the copper layer of the core board itself, there is no need to add other materials such as gaskets and covering films. This prevents the resin material from flowing into the functional area and reduces the manufacturing cost of the printed circuit board.

[0015] See also Figure 1 The printed circuit board of this embodiment includes a core board 11 and a cured layer 12 attached to the core board 11 .

[0016] The core board 11 is provided with a conductive structure; the cured layer 12 is an adhesive material that becomes fluid under the influence of temperature and pressure. It should be noted that this embodiment does not limit the number of core boards 11. Multiple core boards 11 can be provided, arranged sequentially, depending on the needs of the printed circuit board application scenario, with the cured layer 12 located between adjacent core boards 11.

[0017] Furthermore, the core board 11 includes a dielectric layer 111, and a pattern portion 112 and a retaining wall portion 113 formed by etching a copper layer (not shown) laid on the dielectric layer 111. A functional area adjacent to the retaining wall portion 113 is provided on the dielectric layer 111, and the retaining wall portion 113 is located between the functional area and the pattern portion 112.

[0018] Specifically, dielectric layer 111 is an insulating material, and the copper layer is a conductive layer. The copper layer is provided with a pattern portion 112 and a retaining wall portion 113 formed by etching the copper layer. A functional area is provided on dielectric layer 111. Pattern portion 112 serves as the conductive structure of core board 11, and retaining wall portion 113 is a closed structure surrounding the functional area. The retaining wall portion 113 is a closed structure surrounding the functional area, further preventing the uncured solidified layer 12 from flowing into the functional area.

[0019] In this embodiment, a high-speed line 114 is provided in the functional area, and no through-holes are designed within the functional area. Placing the high-speed line 114 in the functional area ensures the stability of signal transmission by the high-speed line 114. The lack of through-holes within the functional area ensures the structural strength of the printed circuit board while protecting the high-speed line 114 from interference from other electrical or magnetic signals during signal transmission.

[0020] The direction from the pattern portion 112 toward the retaining wall portion 113 is defined herein as a first direction (i.e., the X direction in the figure). Preferably, to ensure the structural strength of the retaining wall portion 113, the width of the retaining wall portion 113 in the first direction is no less than 2 mils. In this embodiment, the width of the retaining wall portion 113 in the first direction is 3 mils.

[0021] Preferably, a gap 115 is left between the retaining wall portion 113 and the pattern portion 112; the solidified layer 12 covers the pattern portion 112, retaining wall portion 113, and the functional area on the dielectric layer 111, and fills the gap 115. The dimension of the gap 115 in the first direction is no less than 10 mils, so that the solidified layer 12 can flow back through the gap 115 before curing, that is, when the resin material softens, thereby avoiding damage to the retaining wall portion 113. Furthermore, no through-holes are designed within the gap 115.

[0022] In other alternative embodiments, the printed circuit board further comprises a grounding hole (not shown) extending through the dielectric layer 111; the retaining wall portion 113 is electrically connected to the grounding hole. Furthermore, a connecting line (not shown) is further provided on the copper layer, and the retaining wall portion 113 is electrically connected to the grounding hole via the connecting line.

[0023] See also Figure 2 The printed circuit board provided in the second embodiment of the present invention is substantially the same as that in the first embodiment, except that the thickness of the printed circuit board is greater than or equal to 1.6 mm (mm), and the functional area is a gold finger area, that is, a gold finger 211 is provided in the functional area.

[0024] The direction from the pattern portion 212 to the retaining wall portion 213 is defined as the first direction (ie, the X direction in the figure). The width of the retaining wall portion 213 in the first direction is 4 mils. The retaining wall portion 213 in the first direction is used to separate the solidified layer 214 from the functional area.

[0025] Preferably, in this embodiment, the printed circuit board further comprises a ground pad disposed on the dielectric layer 215 and on the same layer as the retaining wall portion 213; the retaining wall portion 213 is electrically connected to the ground pad (not shown). Furthermore, a connecting line (not shown) is further disposed on the copper layer, electrically connecting the retaining wall portion 213 to the ground pad via the connecting line.

[0026] Embodiment three of the present application relates to a printed circuit board manufacturing method, specifically, the flow chart of the printed circuit board manufacturing method in the embodiment is as shown in Figure 3 The printed circuit board manufacturing method comprises the following steps:

[0027] S301: providing a core plate comprising a dielectric layer and a copper layer laid on the dielectric layer.

[0028] Specifically, the dielectric layer provided in this step is an insulator, and the copper layer is a conductive layer laid on the dielectric layer, and the copper layer and the dielectric layer together constitute the core plate. Further, the dielectric constant of the dielectric layer is less than 3.0; in this embodiment, the dielectric constant of the dielectric layer is 2.6. It should be noted that the number of core plates is not limited in this embodiment, and multiple core plates can be laid in sequence according to the needs of the use scene of the printed circuit board, and the dielectric layer is located between the two adjacent copper layers to maintain the insulation between the two adjacent copper layers.

[0029] S302: etching the copper layer to form a pattern part, a barrier part and a functional area on the dielectric layer.

[0030] Specifically, the copper layer is etched through an exposure and development process to form a pattern part, a barrier part and a functional area on the dielectric layer. That is, a layer of dry film is attached to the surface of the copper layer by heating and pressing after processing, and then the circuit pattern is transferred to the copper surface after ultraviolet irradiation to form a layer of anti-etching mask pattern on the copper surface. Then the copper layer is etched. Since part of the material of the copper layer is provided with an anti-etching mask pattern, the part of the material provided with the anti-etching mask pattern is retained during the etching process, forming a pattern part, a barrier part and a functional area on the dielectric layer.

[0031] In the process of setting the gasket or the cover film in the related art, the gasket is milled or the cover film is printed separately, which increases multiple process flows and prolongs the processing flow of the printed circuit board. The production cycle of the printed circuit board without the gasket or the cover film is generally 15 days, and after the gasket or the cover film design is added, the production cycle of the printed circuit board with the gasket or the cover film is generally 19 days due to the additional auxiliary process, and the production cycle is increased by 4 days.

[0032] The printed circuit board manufacturing method provided in this embodiment forms a pattern part and a barrier part at the same time when etching the copper layer, without the need to add other steps in the manufacturing process of the printed circuit board, and has no effect on the production cycle of the printed circuit board. The printed circuit board manufacturing method provided in this embodiment improves the production efficiency by 30% compared with the related art of setting the gasket or the cover film.

[0033] In addition, the prior art needs to additionally mill a notch, remove oxidation and scan the core board before the process of setting the gasket or the cover film, so as to realize the fitting of the auxiliary material. The manufacturing method of the printed circuit board provided in the embodiment does not need to perform the above additional operations, and accordingly, the operation steps of the staff are reduced, and the manufacturing cost of the printed circuit board is further reduced.

[0034] It is worth noting that in the process of setting the gasket or the cover film, the prior art increases the gasket in the printed circuit board, and since the loss factor of the gasket is greater than the loss factor of the copper layer in the printed circuit board, the loss of the printed circuit board is increased; or when the cover film is added in the printed circuit board, since the dielectric constant of the cover film is greater than the dielectric constant of the dielectric layer in the printed circuit board, the signal transmission rate of the printed circuit board is affected. The manufacturing method of the printed circuit board provided in the embodiment forms the barrier wall part by etching the copper layer, and thus does not increase the loss of the printed circuit board and does not affect the signal transmission rate of the printed circuit board.

[0035] Further, the high-speed line is arranged in the functional area. The high-speed line can be formed at the same time when the copper layer is etched to form the pattern part, the barrier wall part and the functional area on the dielectric layer, and thus the processing flow of the printed circuit board is avoided to be increased.

[0036] Preferably, the design data of the printed circuit board can be edited by using the same type of products as Cadence (computer-aided manufacturing software) or Genesis (computer-aided manufacturing software), such as: first finding the high-speed line in the design data of the printed circuit board, and then editing the design data of the printed circuit board to design the positions of the pattern part, the barrier wall part and the functional area on the copper layer. In the embodiment, the high-speed line is arranged in the functional area, the functional area is adjacent to the barrier wall part, the barrier wall part is arranged between the functional area and the pattern part, and a space is left between the barrier wall part and the pattern part. More preferably, the barrier wall part is a closed structure surrounding the functional area.

[0037] S303: providing a prepreg for fitting to the core board.

[0038] Specifically, the prepreg provided in the embodiment is a sheet-shaped material composed of a resin and a carrier, and the resin material has fluidity under the action of temperature and pressure and can quickly solidify and complete the bonding process. In the embodiment, the prepreg is arranged between two adjacent core boards. The resin material with fluidity contained in the prepreg after being heated and softened flows into the space, and then quickly solidifies to bond the two adjacent core boards together.

[0039] S304: slotting at the position of the functional area corresponding to the prepreg.

[0040] Specifically, grooves are formed in the prepreg at locations corresponding to the functional areas to prevent the prepreg from covering the functional areas. Preferably, the retaining wall portion is a closed structure that surrounds the functional area to form a rectangle. Rectangular slots are formed in the prepreg at locations corresponding to the functional areas. Each side of the rectangular slot corresponds to each side of the rectangular retaining wall portion, and each side of the rectangular slot is at least 6 mils longer than the corresponding side of the retaining wall portion.

[0041] In this embodiment, the retaining wall portion is a closed structure that surrounds the functional area to form a square. A square slot is opened at the position of the semi-cured sheet corresponding to the functional area. The sides of the square slot correspond one-to-one to the sides of the retaining wall portion that forms the square, and the side length of the square slot is 6 mils longer than the side length of the corresponding retaining wall portion.

[0042] S305: Laminating the core board and the prepreg.

[0043] Specifically, the square slot of the prepreg is placed opposite the retaining wall portion, the core board and the prepreg are pressed together, and the prepreg is heated so that the prepreg covers the pattern portion, the retaining wall portion and the functional area on the dielectric layer. Since the retaining wall portion blocks the softened resin material from flowing into the functional area, part of the material of the prepreg is filled into the gap under pressure.

[0044] Preferably, the core board and the prepreg are pressed together at a pressure lower than 360 psi (pounds per square inch) for at least 120 minutes. In this embodiment, the core board and the prepreg are pressed together at a pressure of 350 psi for at least 130 minutes.

[0045] Furthermore, compared with the related art that adopts the method of manufacturing a printed circuit board, the present invention does not need to increase the process of waste materials, saves two steps of opening the cover and removing the gasket, and improves the production efficiency by 10%.

[0046] S306: Curing the prepreg to form a cured layer.

[0047] Specifically, the pressure is removed and the heating of the prepreg is stopped, so that the prepreg is quickly cured to bond the two adjacent core boards together. The cured prepreg forms a cured layer.

[0048] S307: forming a grounding hole connected to the retaining wall portion on the core plate and the solidified layer.

[0049] Specifically, mechanical cutting or laser ablation is used to form a grounding through hole connected to the retaining wall part on the core board and the solidified layer, and the non-conductive part on the through hole wall is metallized by depositing copper to form a grounding hole and realize electrical connection with the retaining wall part.

[0050] See further Figure 4 The manufacturing method of the printed circuit board provided by the embodiment of the present application reduces the loss of the transmission line in the printed circuit board by etching the barrier wall part on the copper layer compared with the related art of setting the pad or the cover film. For example, experiments show that the loss of the transmission line in the scheme of etching the barrier wall part on the copper layer is-0.812 db / inch (db / inch: decibel / inch) at a frequency of 28 GHz (GHz: gigahertz), and the loss of the transmission line in the scheme of setting the pad or the cover film in the related art is-0.760 db / inch; the manufacturing method of the printed circuit board provided by the embodiment of the present application reduces the loss of the transmission line by 6% compared with the related art of setting the pad or the cover film, thereby improving the quality of the transmission signal of the printed circuit board.

[0051] Embodiment four of the present application relates to a manufacturing method of a printed circuit board. Specifically, the flowchart of the manufacturing method of the printed circuit board in the embodiment is as shown in Figure 5 The manufacturing method of the printed circuit board in the embodiment includes the following steps:

[0052] S401: providing a core plate including a dielectric layer and a copper layer laid on the dielectric layer.

[0053] Specifically, the dielectric layer provided in this step is an insulator, and the copper layer is a conductive layer laid on the dielectric layer. The copper layer and the dielectric layer together constitute the core plate. Further, the dielectric constant of the dielectric layer is less than 3.0; in this embodiment, the dielectric constant of the dielectric layer is 2.5. It should be noted that the number of core plates is not limited in this embodiment, and multiple core plates can be laid in sequence according to the needs of the use scene of the printed circuit board. The dielectric layer is located between two adjacent copper layers to maintain the insulation between the two adjacent copper layers.

[0054] S402: etching the copper layer to form a pattern part, a barrier wall part and a functional area on the dielectric layer.

[0055] Specifically, in this embodiment, the copper layer is etched to form a pattern part, a barrier wall part, a functional area and a gold finger on the dielectric layer. The gold finger is located in the functional area, the functional area is adjacent to the barrier wall part, the barrier wall part is located between the functional area and the pattern part, and a gap is left between the barrier wall part and the pattern part. More preferably, the barrier wall part is a closed structure surrounding the functional area.

[0056] S403: optically scanning the barrier wall part.

[0057] Specifically, the barrier wall part is scanned by light to detect whether the barrier wall part has cracks or defects, thereby avoiding the flow of softened resin material into the functional area due to the cracks or defects of the barrier wall part.

[0058] S404: providing a prepreg for bonding to the core plate.

[0059] Specifically, the prepreg is disposed between two adjacent core boards. The prepreg, after being heated and softened, contains a fluid resin material. Part of the resin material flows into the gap and then rapidly solidifies to bond the two adjacent core boards together.

[0060] S405: Grooving is performed at positions of the prepreg corresponding to the functional areas.

[0061] Specifically, the retaining wall portion is a closed structure that surrounds the functional area to form a square. A square slot is opened at the position of the semi-cured sheet corresponding to the functional area. The sides of the square slot correspond one-to-one to the sides of the retaining wall portion that forms the square, and the side length of the square slot is 7 mils longer than the side length of the corresponding retaining wall portion.

[0062] S406: forming a ground pad on the dielectric layer, in the same layer as the retaining wall portion and connected to the retaining wall portion.

[0063] Specifically, copper foil is mounted on the dielectric layer of the rigid circuit board as a soldering pad, so that solder paste can be applied to the soldering pad to electrically connect and secure the device to the printed circuit board. In this embodiment, a grounding copper foil is mounted on the dielectric layer of the rigid circuit board as a grounding pad, and the grounding pad is electrically connected to the retaining wall portion.

[0064] S407: Laminating the core board and the prepreg.

[0065] Specifically, the core board and prepreg are pressed together and heated so that the prepreg covers the patterned portion, retaining wall portion, and functional area on the dielectric layer. The prepreg material is then partially filled into the gaps under pressure. In this embodiment, the core board and prepreg are pressed together using a pressure of 350 psi for a period of no less than 130 minutes.

[0066] S408: Curing the prepreg to form a cured layer.

[0067] Specifically, the pressure is removed and heating of the prepreg is stopped, and the prepreg is rapidly cured to bond two adjacent core boards together, and the cured prepreg forms a cured layer.

[0068] S409: removing the portion of the solidified layer covering the gold finger to expose the gold finger.

[0069] Specifically, the controlled depth milling function of the milling machine is used to remove part of the material of the solidified layer covering the gold finger, so as to remove part of the material of the solidified layer covering the gold finger and expose the gold finger.

[0070] S410: Remove the exposed material of the copper wall.

[0071] Specifically, the milling machine's controlled depth milling function is used to remove the exposed portion of the copper wall material. Furthermore, after removing the exposed portion of the copper wall material, the gold finger can be optically inspected to check its integrity. In this embodiment, step S409 and step S410 are performed simultaneously.

[0072] It should be noted that the method for manufacturing a printed circuit board provided in the third embodiment of the present invention may also adopt steps S403 and S406 of the method for manufacturing a printed circuit board provided in the fourth embodiment of the present invention, and the method for manufacturing a printed circuit board provided in the fourth embodiment of the present invention may also adopt step S307 of the method for manufacturing a printed circuit board provided in the third embodiment of the present invention. The division of steps in the third embodiment of the present invention and the fourth embodiment of the present invention is only for the purpose of clarity of description. During implementation, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent.

[0073] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and that in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A printed circuit board, characterized in that: include: a core panel and a cured layer attached to the core panel; The core board includes a dielectric layer, and a pattern portion and a retaining wall portion formed by etching a copper layer laid on the dielectric layer. A functional area adjacent to the retaining wall portion is provided on the dielectric layer. The retaining wall portion is located between the functional area and the pattern portion. A gap is left between the retaining wall portion and the pattern portion, and the gap is configured to provide a resin flow channel. The solidified layer covers the pattern portion, the retaining wall portion and the functional area on the dielectric layer and fills the gap.

2. The printed circuit board according to claim 1, wherein: A high-speed line is provided in the functional area.

3. The printed circuit board according to claim 2, wherein: The retaining wall portion is a closed structure arranged around the functional area.

4. The printed circuit board according to claim 1, wherein: The functional area is the golden finger area.

5. The printed circuit board according to any one of claims 1 to 4, characterized in that: A direction from the pattern portion to the retaining wall portion is a first direction; a width of the retaining wall portion in the first direction is not less than 2 mils.

6. The printed circuit board according to any one of claims 1 to 4, characterized in that: A direction from the pattern portion to the retaining wall portion is a first direction; and a dimension of the interval in the first direction is not less than 10 mils.

7. The printed circuit board according to any one of claims 1 to 4, characterized in that: Also includes: a grounding hole penetrating the dielectric layer, or a grounding pad provided on the dielectric layer and on the same layer as the retaining wall portion; The retaining wall portion is electrically connected to the grounding hole or the grounding pad.

8. A method for manufacturing a printed circuit board, characterized in that: include: Providing a core board including a dielectric layer and a copper layer laid on the dielectric layer; Etching the copper layer to form a pattern portion, a retaining wall portion, and a functional area on the dielectric layer, wherein the functional area is adjacent to the retaining wall portion, the retaining wall portion is located between the functional area and the pattern portion, and a gap is left between the retaining wall portion and the pattern portion, and the gap is configured to provide a resin flow channel; providing a prepreg for attaching to the core panel; Cutting grooves at positions of the prepreg corresponding to the functional areas; Pressing the core board and the prepreg together so that the prepreg covers the pattern portion, the retaining wall portion, and the functional area on the dielectric layer, and allowing part of the prepreg material to fill the gap under pressure; The prepreg is cured to form a cured layer.

9. The method for manufacturing a printed circuit board according to claim 8, wherein: The etching of the copper layer to form a pattern portion, a retaining wall portion, and a functional area on the dielectric layer specifically includes: etching the copper layer to form a pattern portion, a retaining wall portion, a functional area on the dielectric layer, and a high-speed line in the functional area.

10. The method for manufacturing a printed circuit board according to claim 8, wherein: The etching of the copper layer to form a pattern portion, a retaining wall portion, and a functional area on the dielectric layer specifically includes: etching the copper layer to form a pattern portion, a retaining wall portion, a functional area on the dielectric layer, and a gold finger in the functional area.

11. The method for manufacturing a printed circuit board according to claim 10, wherein: After curing the prepreg to form a cured layer, the method further includes: removing a portion of the cured layer covering the gold finger to expose the gold finger.

12. The method for manufacturing a printed circuit board according to claim 8, wherein: The retaining wall portion is a closed structure surrounding the functional area to form a rectangle.

13. The method for manufacturing a printed circuit board according to claim 12, wherein: The slotting at the position of the semi-cured sheet corresponding to the functional area specifically includes: opening a rectangular slot at the position of the semi-cured sheet corresponding to the functional area, each side of the rectangular slot corresponding to each side of the rectangular retaining wall portion, and the length of each side of the rectangular slot is at least 6 mils greater than the length of each side of the corresponding retaining wall portion.

14. The method for manufacturing a printed circuit board according to any one of claims 8 to 13, characterized in that: After etching the copper layer to form a pattern portion, a retaining wall portion and a functional area on the dielectric layer, the method further includes optically scanning the retaining wall portion.

15. The method for manufacturing a printed circuit board according to any one of claims 8 to 13, characterized in that: The pressing of the core board and the prepreg specifically includes: pressing the core board and the prepreg using a pressure lower than 360 psi, and the pressing time is not less than 120 minutes.

16. The method for manufacturing a printed circuit board according to any one of claims 8 to 13, characterized in that: Before the core board and the prepreg are pressed together, the method further includes: forming a ground pad on the dielectric layer, which is in the same layer as the retaining wall portion and is connected to the retaining wall portion.

17. The method for manufacturing a printed circuit board according to any one of claims 8 to 13, characterized in that: After curing the prepreg to form a cured layer, the method further includes forming a grounding hole connected to the retaining wall portion on the core plate and the cured layer.

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