PCB and preparation method thereof

Abstract

The invention discloses a PCB (Printed Circuit Board) and a preparation method thereof. The PCB comprises an intermediate board, a first differential board, a first outer board, a second differential board and a second outer board, the first differential plate and the second differential plate are arranged on the two side faces of the middle plate respectively, the first outer plate is arranged on the side face, away from the middle plate, of the first differential plate, and the second outer plate is arranged on the side face, away from the middle plate, of the second differential plate. The first differential plate is provided with a first differential transmission line, and the second differential plate is provided with a second differential transmission line; the PCB further comprises open holes, and the open holes comprise round holes and arc-shaped holes; the first outer plate and the second outer plate are also sequentially provided with a copper layer and a nickel-gold layer; and the holes are filled with resin. A strong inductance structure is formed by the first differential transmission line, the second differential transmission line, the hole wall and the nickel-gold layer, the PCB can meet the choking effect under the condition that an external inductor is not needed, and meanwhile low cost and miniaturization can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB boards, and in particular to a PCB board and a preparation method thereof. Background Art

[0002] With the continuous development of technology, the size of electronic components has been continuously reduced and their functions have been continuously enhanced, making it possible to integrate more functions in a limited space. This not only improves the processing power and efficiency of the device, but also reduces energy consumption and prolongs battery life. At the same time, consumers' growing demand for portability and mobility has driven the development of devices towards lighter, thinner and smaller. The popularity of products such as smartphones, tablets and wearable devices requires them to reduce their size and weight as much as possible while maintaining powerful functions for easy carrying and use.

[0003] In the differential transmission line of the PCB board, if a strong common-mode signal appears, the conventional choke method requires an external inductor, which requires an additional large device, takes up space, is not conducive to the miniaturization of the device, and embedding components on the PCB board will result in high costs. Therefore, the PCB board of the prior art cannot achieve low cost and miniaturization while meeting the choke effect. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, an object of the present invention is to provide a PCB board and a preparation method thereof, which can achieve low cost and miniaturization while satisfying the choking effect.

[0005] In order to solve the above problems, the present invention is implemented according to the following scheme:

[0006] A PCB board is provided, comprising a middle board, a first differential board, a first outer board, a second differential board and a second outer board;

[0007] The first differential board and the second differential board are respectively arranged on two side surfaces of the middle board, the first outer board is arranged on a side surface of the first differential board away from the middle board, and the second outer board is arranged on a side surface of the second differential board away from the middle board; the first differential board is provided with a first differential transmission line, and the second differential board is provided with a second differential transmission line;

[0008] The PCB board also includes openings, and the openings include circular holes and arc holes;

[0009] The first outer plate and the second outer plate are also provided with a copper layer and a nickel-gold layer in sequence; and the opening is filled with resin.

[0010] Compared with the prior art, the beneficial effects of a PCB board of the present invention are as follows: by respectively arranging the first differential transmission line and the second differential transmission line on two different levels of the first differential board and the second differential board, the first differential transmission line and the second differential transmission line are distributed up and down, thereby avoiding the problem of insufficient coupling due to limited copper thickness and small facing area during same-layer wiring, so that the line spacing can be smaller, thereby reducing the requirements for process accuracy, simplifying the manufacturing process, and reducing costs; at the same time, a strong inductance structure is formed by the first differential transmission line, the second differential transmission line, the hole wall and the nickel-gold layer, so that the PCB board can meet the choke effect without the need for an external inductor, and at the same time, low cost and miniaturization can be achieved.

[0011] Optionally, the first differential transmission line and the second differential transmission line are arranged in parallel.

[0012] Optionally, the first differential transmission line is set as a serpentine line, and the second differential transmission line is set as a serpentine line.

[0013] Optionally, the circular hole is arranged on the concave side of the serpentine line.

[0014] Optionally, the arc-shaped hole is arranged on the convex side of the serpentine line.

[0015] A method for preparing a PCB board is also provided, which is applicable to the above-mentioned PCB board, comprising:

[0016] A substrate including an intermediate plate, a first differential plate and a second differential plate is provided;

[0017] At the same time, etching and wiring are performed on the first differential board and the second differential board of the substrate to obtain a first differential transmission line with a serpentine line on the first differential board and a second differential transmission line with a serpentine line on the second differential board;

[0018] A first outer plate is arranged on a side of the first differential plate away from the middle plate, and a second outer plate is arranged on a side of the second differential plate away from the middle plate;

[0019] Performing hole-opening processing on the substrate including the middle plate, the first differential plate, the first outer plate, the second differential plate and the second outer plate, opening a circular hole on the concave side of the serpentine line and opening an arc-shaped hole on the convex side of the serpentine line;

[0020] The substrate is subjected to copper plating treatment to obtain a copper-clad plate in which the hole walls of the circular holes and the arc-shaped holes in the substrate, the surfaces of the first differential transmission line and the second differential transmission line are all covered with a copper layer;

[0021] Performing nickel-gold treatment on the surface of the copper-clad laminate;

[0022] The circular hole and the arc-shaped hole are plugged with resin.

[0023] Optionally, the line width of the first differential transmission line and the line width of the second differential transmission line are both target line widths.

[0024] Optionally, the distance range between the first differential plate and the second differential plate does not exceed a line distance threshold;

[0025] The line spacing threshold is 1.5 times the target line width.

[0026] Optionally, the hole line distance between the circular holes and the serpentine lines and the hole line distance between the arc holes and the serpentine lines are both target hole line distances.

[0027] Optionally, the upper limit of the value range of the target hole line spacing is 3 times the target line width;

[0028] The lower limit of the value range of the target hole line spacing is 0.5 times the target line width. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural diagram of the PCB board of the present invention;

[0030] Figure 2 It is a schematic diagram of the magnetic field distribution of differential mode signals;

[0031] Figure 3 It is a schematic diagram of the magnetic field distribution of common mode signals;

[0032] Figure 4 The figure is a curve comparison diagram of the common-mode insertion loss and the differential-mode insertion loss of the PCB board of the present invention and the PCB board of the same length with conventional design.

[0033] Explanation of the reference numerals: 1. middle plate; 2. first differential plate; 201. first differential transmission line; 3. second differential plate; 301. second differential transmission line; 4. first outer plate; 5. second outer plate; 6. opening; 601. circular hole; 602. arc hole. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0035] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0036] See also Figure 1 As shown, the present invention provides a PCB board, including an intermediate board 1, a first differential board 2, a first outer board 4, a second differential board 3 and a second outer board 5; the first differential board 2 and the second differential board 3 are respectively arranged on two side surfaces of the intermediate board 1, the first outer board 4 is arranged on a side surface of the first differential board 2 away from the intermediate board 1, and the second outer board 5 is arranged on a side surface of the second differential board 3 away from the intermediate board 1; the first outer board 4 and the second outer board 5 are also provided with a copper layer and a nickel-gold layer in sequence.

[0037] The first differential board 2 is provided with a first differential transmission line 201, and the second differential board 3 is provided with a second differential transmission line 301, wherein the first differential transmission line 201 and the second differential transmission line 301 are arranged in parallel, the first differential transmission line 201 is set as a serpentine line, and the second differential transmission line 301 is set as a serpentine line.

[0038] Since the thickness of the copper layer affects the magnetic field between the lines, the thicker the copper layer, the stronger the magnetic field generated by the differential mode signal between the first differential transmission line 201 and the second differential transmission line 301, which will affect the transmission quality and anti-interference ability of the signal, so the thickness of the copper layer needs to be limited.

[0039] When the first differential transmission line 201 and the second differential transmission line 301 are located in the same layer, due to the limited thickness of the copper layer, the facing area is small, that is, the overlapping area between the first differential transmission line 201 and the second differential transmission line 301 is small. At this time, it is necessary to increase the coupling degree between the first differential transmission line 201 and the second differential transmission line 301 to improve the transmission quality and anti-interference ability of the signal. By reducing the line distance between the first differential transmission line 201 and the second differential transmission line 301, the coupling degree between the first differential transmission line 201 and the second differential transmission line 301 can be effectively increased. However, reducing the distance between the first differential transmission line 201 and the second differential transmission line 301 has a negative impact on the signal transmission quality and anti-interference ability. The process precision requirement of the PCB board is very high, that is, when the first differential transmission line 201 and the second differential transmission line 301 are located in the same layer, it is difficult to increase the facing area; therefore, the present invention can avoid the distance limitation between the first differential transmission line 201 and the second differential transmission line 301 by setting the first differential transmission line 201 and the second differential transmission line 301 to be distributed in the upper and lower layers, and can increase the inductance per unit length of the differential transmission line by setting the first differential transmission line 201 and the second differential transmission line 301 to be serpentine lines, and can improve the choke effect of the PCB board without additionally setting inductor components, and can also achieve low cost and miniaturization of the PCB board.

[0040] During the preparation process of the PCB board, in order to ensure that the first differential transmission line 201 and the second differential transmission line 301 can be arranged in parallel, that is, to ensure the external accuracy of the first differential board 2 and the second differential board 3, it is necessary to etch the first differential board 2 and the second differential board 3 at the same time to prepare the first differential transmission line 201 on the first differential board 2 and the second differential transmission line 301 on the second differential board 3.

[0041] The PCB board also includes an opening 6, which includes a circular hole 601 and an arc-shaped hole 602. The opening 6 is filled with resin; the circular hole 601 is arranged on the concave side of the serpentine line, and the arc-shaped hole 602 is arranged on the convex side of the serpentine line. Since the arc-shaped hole 602 is an irregular hole, in order to improve the accuracy of the arc-shaped hole 602, it is necessary to use a laser for drilling.

[0042] The present invention forms a strong inductance structure through the first differential transmission line 201, the second differential transmission line 301, the hole wall and the nickel-gold layer, which can make the PCB board meet the choke effect without the need for an external inductor, and can also achieve low cost and miniaturization.

[0043] Differential mode signals are a pair of signals of equal magnitude and opposite polarity, see Figure 2, which is a schematic diagram of the magnetic field distribution of the differential signal, the directions of the magnetic fields between the first differential transmission line 201 and the second differential transmission line 301 are the same and reinforce each other, while the directions of the peripheral magnetic fields of the first differential transmission line 201 and the second differential transmission line 301 are opposite and cancel each other out.

[0044] Common-mode signals are a pair of signals of equal magnitude and polarity, see Figure 3 , which is a schematic diagram of the common-mode signal magnetic field distribution, the directions of the magnetic fields between the first differential transmission line 201 and the second differential transmission line 301 are opposite and cancel each other out, while the directions of the peripheral magnetic fields between the first differential transmission line 201 and the second differential transmission line 301 are the same and reinforce each other.

[0045] Assuming that the current of a single channel is I, the first differential transmission line 201 and the second differential transmission line 301 can be regarded as a whole at a position far from the signal line, and the magnetic field strength generated is:

[0046]

[0047] Wherein, B is the magnetic field intensity, μ0 is the magnetic permeability in vacuum, and r is the center distance between the first differential transmission line 201 and the second differential transmission line 301 .

[0048] The cross-sectional magnetic flux around the differential transmission line from the midpoint between the first differential transmission line 201 and the second differential transmission line 301 to a unit length r from the center is:

[0049]

[0050] Wherein, φ is the cross-sectional magnetic flux, I is the single-channel current, μ0 is the magnetic permeability in vacuum, r is the center distance between the first differential transmission line 201 and the second differential transmission line 301, w is the line width of the first differential transmission line 201 and the second differential transmission line 301, be is the line spacing between the first differential transmission line 201 and the second differential transmission line 301, and be / w∈[0.5, 2] of the conventional differential transmission line, that is, the ratio of the line width to the line spacing is a value between 0.5 and 2, that is, That is, when the opening 6 is within 1 to 3 times the line width from the first differential transmission line 201 or the second differential transmission line 301, there is still a strong magnetic field and the magnetic flux increases significantly. Therefore, in order to suppress the common mode signal and have a small impact on the differential mode signal, when drilling to obtain the circular hole 601 and the arc hole 602, it is necessary to set the opening 6 at 0.5 to 3 times the line width from the first differential transmission line 201 or the second differential transmission line 301 to ensure that the hole line spacing between the circular hole 601 and the serpentine line and the hole line spacing between the arc hole 602 and the serpentine line are in the range of 0.5 to 3 times the line width.

[0051] See also Figure 3As shown, the common-mode signal magnetic fields between the first differential transmission line 201 and the second differential transmission line 301 cancel each other out. When the line distance between the first differential transmission line 201 and the second differential transmission line 301 is designed, that is, when the thickness of the intermediate plate 1 is selected in the present invention, the common-mode signal is suppressed. The strongest magnetic field strength generated by the common-mode signal between the first differential transmission line 201 and the second differential transmission line 301 is:

[0052]

[0053] Among them, B MAX is the strongest magnetic field intensity, I is the single channel current, μ0 is the magnetic permeability in vacuum, r is the center distance between the first differential transmission line 201 and the second differential transmission line 301, w is the line width of the first differential transmission line 201 and the second differential transmission line 301, and be is the line distance between the first differential transmission line 201 and the second differential transmission line 301.

[0054] In order to ensure that the magnetic field strength generated by the common-mode signal is small enough, the target magnetic field strength of the present invention is less than 1 / 4 of the magnetic field strength at the edge of a single differential transmission line, and the expression is as follows:

[0055]

[0056] Thus, be≤1.5w is obtained, that is, the line distance between the first differential transmission line 201 and the second differential transmission line 301 is less than or equal to 1.5 times the line width of the first differential transmission line 201 and the second differential transmission line 301. In the present invention, the line distance between the first differential transmission line 201 and the second differential transmission line 301 is the thickness of the intermediate board 1, that is, the thickness of the intermediate board 1 should be less than or equal to 1.5 times the line width of the first differential transmission line 201 and the second differential transmission line 301.

[0057] See also Figure 4 As shown, it is a curve comparison diagram of the common-mode insertion loss and differential-mode insertion loss of the PCB board of the present invention and the PCB board of the same length conventional design in the range of 0 to 20 Hz; wherein, the PCB board of the same length conventional design means that the two differential transmission lines on the PCB board are the same as the first differential transmission line 201 and the second differential transmission line 301 of the present invention in length, relative position, impedance, and line width, and the preparation process of the PCB board of the present invention and the PCB board of the same length conventional design are both conventional PCB processing processes to ensure the consistency of signal transmission when comparing, but there is no opening 6 on the PCB board of the present invention.

[0058] Common-mode insertion loss refers to the loss suffered by the common-mode signal during the transmission process of differential signal transmission, that is, the larger the absolute value of the common-mode insertion loss, the stronger the PCB board's ability to suppress common-mode signals; differential-mode insertion loss refers to the loss suffered by the differential-mode signal during the transmission process of differential signal transmission, that is, the smaller the absolute value of the differential-mode insertion loss, the higher the PCB board's signal transmission efficiency.

[0059] Figure 4 The curve Scc2,1 is used to represent the common-mode insertion loss of the PCB board of the present invention, the curve Sdd2,1 is used to represent the differential-mode insertion loss of the PCB board of the present invention, the curve Scc2,2 is used to represent the common-mode insertion loss of the conventionally designed PCB board of equal length, and the curve Sdd2,2 is used to represent the differential-mode insertion loss of the conventionally designed PCB board of equal length.

[0060] Depend on Figure 4 It can be seen that, at the same signal frequency (the signal frequency in the figure is 10 GHz) of the PCB board of the present invention and the conventionally designed PCB board of the same length, the absolute value of the common-mode insertion loss (Scc2,1) of the PCB board of the present invention is greater than the absolute value of the common-mode insertion loss (Scc2,2) of the conventionally designed PCB board of the same length, that is, the PCB board of the present invention has a stronger ability to suppress common-mode signals than the conventionally designed PCB board of the same length; the difference between the common-mode insertion loss (Scc2,1) and the differential-mode insertion loss (Sdd2,1) of the PCB board of the present invention is greater than the difference between the common-mode insertion loss (Scc2,2) and the differential-mode insertion loss (Sdd2,2) of the conventionally designed PCB board of the same length, that is, the choking effect of the PCB board of the present invention is greater than the choking effect of the conventionally designed PCB board of the same length. better; in the range of 0 to 20 GHz, the differential mode insertion loss (Sdd2,1) of the PCB board of the present invention is close to the differential mode insertion loss (Sdd2,2) of the PCB board of the same length with conventional design, and the higher the signal frequency, the enhanced suppression capabilities of the PCB board of the present invention and the PCB board of the same length with conventional design on common mode signals, but the suppression capability of the PCB board of the present invention on common mode signals is better than that of the PCB board of the same length with conventional design, and the difference between the common mode insertion loss (Scc2,1) and the differential mode insertion loss (Sdd2,1) of the PCB board of the present invention is greater than the increase amplitude of the PCB board of the same length with conventional design, that is, under high frequency signals, while ensuring the normal transmission of differential mode signals, the choking effect of the PCB board of the present invention is significantly better than the choking effect of the PCB board of the same length with conventional design.

[0061] The present invention also provides a method for preparing a PCB board, applicable to a PCB board, comprising:

[0062] S1: a substrate including an intermediate plate 1, a first differential plate 2 and a second differential plate 3 is provided;

[0063] S2: Etching and routing the first differential plate 2 and the second differential plate 3 of the substrate at the same time, obtaining a first differential transmission line 201 with a serpentine routing on the first differential plate 2, and a second differential transmission line 301 with a serpentine routing on the second differential plate 3; wherein, when etching and routing the first differential plate 2 and the second differential plate 3, the line width of the first differential transmission line 201 and the line width of the second differential transmission line 301 are both set as the target line width; the distance range between the first differential plate 2 and the second differential plate 3 does not exceed the line distance threshold, that is, the first differential transmission line 2 01 and the second differential transmission line 301 does not exceed the line spacing threshold, that is, the thickness of the intermediate board 1 does not exceed the line spacing threshold; the common-mode signal magnetic fields between the first differential transmission line 201 and the second differential transmission line 301 cancel each other out. When the line spacing between the first differential transmission line 201 and the second differential transmission line 301 is designed, that is, when the thickness of the intermediate board 1 is selected in the present invention, the common-mode signal is suppressed. The strongest magnetic field strength generated by the common-mode signal between the first differential transmission line 201 and the second differential transmission line 301 is:

[0064]

[0065] Among them, B MAX is the strongest magnetic field intensity, I is the single channel current, μ0 is the magnetic permeability in vacuum, r is the center distance between the first differential transmission line 201 and the second differential transmission line 301, w is the line width of the first differential transmission line 201 and the second differential transmission line 301, and be is the line distance between the first differential transmission line 201 and the second differential transmission line 301.

[0066] In order to ensure that the magnetic field strength generated by the common-mode signal is small enough, the target magnetic field strength is less than 1 / 4 of the magnetic field strength edge of a single differential transmission line, and the expression is as follows:

[0067]

[0068] Thus, be≤1.5w is obtained, that is, the line distance between the first differential transmission line 201 and the second differential transmission line 301 is less than or equal to 1.5 times the line width of the first differential transmission line 201 and the second differential transmission line 301. In the present invention, the line distance between the first differential transmission line 201 and the second differential transmission line 301 is the thickness of the intermediate board 1, that is, the thickness of the intermediate board 1 should be less than or equal to 1.5 times the line width of the first differential transmission line 201 and the second differential transmission line 301, so the line distance threshold is 1.5 times the target line width.

[0069] S3: a first outer plate 4 is arranged on a side of the first differential plate 2 away from the middle plate 1, and a second outer plate 5 is arranged on a side of the second differential plate 3 away from the middle plate 1;

[0070] S4: Perform hole opening treatment on the substrate including the middle plate 1, the first differential plate 2, the first outer plate 4, the second differential plate 3 and the second outer plate 5, and open a circular hole 601 on the concave side of the serpentine line, and open an arc hole 602 on the convex side of the serpentine line; wherein, when performing the hole opening treatment, the hole line spacing between the circular hole 601 and the serpentine line and the hole line spacing between the arc hole 602 and the serpentine line are set as the target hole line spacing; assuming that the current of a single channel is I, the first differential transmission line 201 and the second differential transmission line 301 can be regarded as a whole at a position far from the signal line in the periphery, and the magnetic field strength generated is:

[0071]

[0072] Wherein, B is the magnetic field intensity, μ0 is the magnetic permeability in vacuum, and r is the center distance between the first differential transmission line 201 and the second differential transmission line 301 .

[0073] The cross-sectional magnetic flux around the differential transmission line from the midpoint between the first differential transmission line 201 and the second differential transmission line 301 to a unit length r from the center is:

[0074]

[0075] Wherein, φ is the cross-sectional magnetic flux, I is the single-channel current, μ0 is the magnetic permeability in vacuum, r is the center distance between the first differential transmission line 201 and the second differential transmission line 301, w is the line width of the first differential transmission line 201 and the second differential transmission line 301, be is the line spacing between the first differential transmission line 201 and the second differential transmission line 301, and be / w∈[0.5, 2] of the conventional differential transmission line, that is, the ratio of the line width to the line spacing is a value between 0.5 and 2, that is, That is, when the opening 6 is within 1 to 3 times the line width from the first differential transmission line 201 or the second differential transmission line 301, there is still a strong magnetic field and the magnetic flux increases significantly. Therefore, in order to suppress the common mode signal and have a small impact on the differential mode signal, when drilling to obtain the circular hole 601 and the arc hole 602, it is necessary to make a hole at 0.5 to 3 times the line width from the first differential transmission line 201 or the second differential transmission line 301 to ensure that the hole line spacing between the circular hole 601 and the serpentine line and the hole line spacing between the arc hole 602 and the serpentine line are in the range of 0.5 to 3 times the line width; therefore, the upper limit of the value range of the target hole line spacing is 3 times the target line width, and the lower limit of the value range of the target hole line spacing is 0.5 times the target line width.

[0076] S5: copper plating the substrate to obtain a copper-clad plate in which the hole walls of the circular hole 601 and the arc-shaped hole 602 in the substrate, and the surfaces of the first differential transmission line 201 and the second differential transmission line 301 are all covered with a copper layer;

[0077] S6: Perform nickel-gold treatment on the surface of the copper clad laminate;

[0078] S7: Use resin to plug the circular hole 601 and the arc hole 602.

[0079] By performing a hole opening 6 treatment on the substrate to obtain a hole wall, and performing a nickel-gold treatment on the surface of the copper-clad board to obtain a nickel-gold layer, a strong inductance structure is formed by the first differential transmission line 201, the second differential transmission line 301, the hole wall and the nickel-gold layer. The PCB board can also meet the choke effect without the need for an external inductor, while achieving low cost and miniaturization.

[0080] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A PCB board, characterized in that: It includes a middle plate, a first differential plate, a first outer plate, a second differential plate and a second outer plate; The first differential board and the second differential board are respectively arranged on two side surfaces of the middle board, the first outer board is arranged on a side surface of the first differential board away from the middle board, and the second outer board is arranged on a side surface of the second differential board away from the middle board; the first differential board is provided with a first differential transmission line, and the second differential board is provided with a second differential transmission line; The PCB board also includes openings, and the openings include circular holes and arc holes; The first outer plate and the second outer plate are also provided with a copper layer and a nickel-gold layer in sequence; and the opening is filled with resin.

2. A PCB board according to claim 1, characterized in that: The first differential transmission line is arranged in parallel with the second differential transmission line.

3. A PCB board according to claim 2, characterized in that: The first differential transmission line is configured as a serpentine line, and the second differential transmission line is configured as a serpentine line.

4. A PCB board according to claim 3, characterized in that: The circular hole is arranged on the concave side of the serpentine line.

5. A PCB board according to claim 3, characterized in that: The arc-shaped hole is arranged on the convex side of the serpentine line.

6. A method for preparing a PCB board, applicable to a PCB board as claimed in any one of claims 1 to 5, characterized in that: include: A substrate including an intermediate plate, a first differential plate and a second differential plate is provided; At the same time, etching and wiring are performed on the first differential board and the second differential board of the substrate to obtain a first differential transmission line with a serpentine line on the first differential board and a second differential transmission line with a serpentine line on the second differential board; A first outer plate is arranged on a side of the first differential plate away from the middle plate, and a second outer plate is arranged on a side of the second differential plate away from the middle plate; Performing hole-opening processing on the substrate including the middle plate, the first differential plate, the first outer plate, the second differential plate and the second outer plate, opening a circular hole on the concave side of the serpentine line and opening an arc-shaped hole on the convex side of the serpentine line; The substrate is subjected to copper plating treatment to obtain a copper-clad plate in which the hole walls of the circular holes and the arc-shaped holes in the substrate, the surfaces of the first differential transmission line and the second differential transmission line are all covered with a copper layer; Performing nickel-gold treatment on the surface of the copper-clad laminate; The circular hole and the arc-shaped hole are plugged with resin.

7. The method for preparing a PCB board according to claim 6, characterized in that: The line width of the first differential transmission line and the line width of the second differential transmission line are both target line widths.

8. The method for preparing a PCB board according to claim 7, characterized in that: The distance range between the first differential plate and the second differential plate does not exceed the line distance threshold; The line spacing threshold is 1.5 times the target line width.

9. The method for preparing a PCB board according to claim 7, characterized in that: The hole line distance between the circular hole and the serpentine line and the hole line distance between the arc hole and the serpentine line are both target hole line distances.

10. The method for preparing a PCB board according to claim 9, characterized in that: The upper limit of the range of the target hole line spacing is 3 times the target line width; The lower limit of the value range of the target hole line spacing is 0.5 times the target line width.

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