Circuit board and manufacturing method thereof

Abstract

The invention discloses a circuit board and a manufacturing method thereof, the manufacturing method of the circuit board comprises the following steps: providing an inner-layer board, a bonding sheet and an outer-layer board, the inner-layer board is provided with an inner-layer bonding pad, and the bonding sheet is provided with a window part; covering the inner layer bonding pad with protective ink; the bonding sheet is stacked between the inner layer board and the outer layer board so that the inner layer bonding pad can be located in the window part, and the inner layer board, the bonding sheet and the outer layer board are laminated so that the window part can be filled with the PP glue overflowing from the bonding sheet; removing an area, corresponding to the inner-layer bonding pad, of the outer-layer plate; removing the PP glue at the window part; and removing the protective ink. Therefore, the safety of the inner layer bonding pad can be ensured, and the inner layer bonding pad can be exposed at the same time. The circuit board is widely applied to the technical field of circuit boards.

Description

Technical Field

[0001] The present application relates to the technical field of circuit boards, and in particular to a circuit board and a method for manufacturing the same. Background Art

[0002] Since the finished products of millimeter wave products need to accurately measure the inner layer circuit capacity, the inner layer pads must be exposed after the circuit board is finished, so that the test probe can contact the inner layer pads to measure the inner layer circuit capacity. At the same time, in order to ensure the communication capability and operation reliability of the product, the best way is to completely expose the inner layer pads without affecting the integrity of the outer layer medium.

[0003] At present, the commonly used processing method to expose the inner pad is to use CNC milling or laser burning process to remove the position of the corresponding inner pad of the adhesive sheet (i.e., semi-cured sheet, also known as PP sheet). Since the adhesive sheet is combined with the inner layer of the circuit board after lamination, if the adhesive sheet above the inner pad is to be completely removed to make it completely exposed, it is bound to cause damage to the copper surface of the inner pad. If the adhesive sheet is used to open a window in advance, since the inner pad of millimeter wave products is a tiny pad, the size of the inner pad is usually between 0.1mm-0.4mm, and the diameter of the test probe used to detect the inner line capability is usually between 0.6mm-0.8mm, the window size of the adhesive sheet will not be very large. After lamination, the window position of the adhesive sheet will be filled with overflow glue, so that the inner pad cannot be exposed. Therefore, it is urgent to find a technical solution that can meet the inner line measurement of millimeter wave products. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a method for manufacturing a circuit board, which can expose the inner layer pads while ensuring the safety of the inner layer pads.

[0005] The present application also proposes a circuit board manufactured using the above-mentioned circuit board manufacturing method.

[0006] According to the first aspect of the present application, a method for manufacturing a circuit board is characterized by comprising:

[0007] Providing an inner layer board, an adhesive sheet and an outer layer board, wherein the inner layer board is provided with an inner layer pad, and the adhesive sheet is provided with a window portion;

[0008] Covering the inner pad with protective ink;

[0009] The adhesive sheet is stacked between the inner layer board and the outer layer board so that the inner layer pad is located in the window portion, and the inner layer board, the adhesive sheet and the outer layer board are laminated so that the PP glue overflowing from the adhesive sheet fills the window portion;

[0010] Removing the area of ​​the outer layer board corresponding to the inner layer pad;

[0011] Remove the PP glue from the window;

[0012] The protective ink is removed.

[0013] The method for manufacturing a circuit board according to the embodiment of the present application has at least the following beneficial effects: by covering the inner layer pad with protective ink to isolate the adhesive sheet and the inner layer pad during lamination, it is beneficial to protect the inner layer pad when removing the adhesive sheet or PP glue, thereby ensuring that the inner layer pad will not be damaged when the medium above the inner layer pad is removed, so as to improve the safety of the inner layer pad, and finally, the inner layer pad is exposed by fading the protective ink to achieve the exposure of the inner layer pad, thereby meeting the design requirement of exposing the inner layer pad while ensuring the safety of the inner layer pad, and at the same time, by opening a window on the adhesive sheet in advance and the window portion is arranged corresponding to the protective ink, the window portion can reserve space for the protective ink, so that the circuit board maintains a smooth surface after lamination, so as to improve the reliability of the circuit board.

[0014] According to some embodiments of the present application, a laser depth-controlled process is used to remove the PP glue from the window portion.

[0015] According to some embodiments of the present application, when the laser depth control process is used to remove the PP glue in the window portion, the drill is controlled to move until it contacts the protective ink.

[0016] According to some embodiments of the present application, the window portion penetrates both side surfaces of the adhesive sheet.

[0017] According to some embodiments of the present application, the material of the protective ink includes epoxy resin, and the protective ink is combined with the PP glue after lamination.

[0018] According to some embodiments of the present application, the protective ink is removed by using a film stripping section for making the circuit of the outer layer board.

[0019] According to some embodiments of the present application, during the circuit manufacturing process of the outer layer board, the area of ​​the outer layer board corresponding to the inner layer pad is removed.

[0020] According to some embodiments of the present application, the size of the inner pad is 0.1 mm-0.4 mm.

[0021] According to some embodiments of the present application, the thickness of the adhesive sheet is 60 um-160 mm, and / or the RC content in the adhesive sheet is 60%-80%.

[0022] The circuit board according to the second aspect of the present application is manufactured using the method for manufacturing the circuit board as described in the first aspect above.

[0023] The circuit board according to the embodiment of the present application has at least the following beneficial effect: the inner layer pads can be exposed while the safety of the inner layer pads is ensured.

[0024] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present application is further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 A schematic diagram of a process for manufacturing a circuit board disclosed in an embodiment of the present application;

[0027] Figure 2 A schematic diagram of the structure of a circuit board manufactured based on a method for manufacturing a circuit board according to an embodiment of the present application;

[0028] Figure 3 A schematic diagram of a circuit board manufactured by a method for manufacturing a circuit board according to an embodiment of the present application, with protective ink being covered on an inner pad;

[0029] Figure 4 A schematic diagram of a pad when a protective ink is covered on an inner pad of a circuit board manufactured by a method for manufacturing a circuit board according to an embodiment of the present application;

[0030] Figure 5 A schematic diagram of the structure of a circuit board manufactured by a method for manufacturing a circuit board according to an embodiment of the present application during lamination;

[0031] Figure 6 This is a schematic diagram of the structure of a circuit board manufactured by a circuit board manufacturing method based on an embodiment of the present application when the area of ​​the outer layer board corresponding to the inner layer pad, PP glue and protective ink are removed.

[0032] Reference numerals:

[0033] 1. Circuit board; 10. Inner board; 101. Inner pad; 102. Inner circuit; 20. Adhesive sheet; 201. Window; 202. PP glue; 30. Outer board; 40. Protective ink. DETAILED DESCRIPTION

[0034] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0035] In the description of the present application, it should be understood that the terms "center", "middle", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0036] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0037] In the description of this application, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In the description of the present application, if the reference terms "as an implementation", "an embodiment", "some instances", "some embodiments", "illustrative embodiment", "example", "specific example", "some examples", etc. appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0039] Millimeter wave products usually require the inner pads of the circuit board to be completely exposed. The commonly used processing method to expose the inner pads is to use CNC milling or laser burning to remove the adhesive sheet (i.e., prepreg, also known as PP sheet) corresponding to the position of the inner pad. Since the adhesive sheet is combined with the inner layer of the circuit board after lamination, if the adhesive sheet above the inner pad is to be completely removed to make it completely exposed, it is bound to damage the copper surface of the inner pad, thereby affecting the work of the inner pad. If the adhesive sheet above the inner pad is not completely removed, the inner pad cannot be completely exposed.

[0040] In the related art, for products with larger inner pads, in order to omit the step of removing the adhesive sheet above the inner pad, a method of pre-opening a window on the adhesive sheet is usually adopted. A window is opened at the position of the adhesive sheet corresponding to the inner pad. Due to the large window area, the overflow of the adhesive sheet during lamination will not overflow to the inner pad through the window (or will not completely cover the inner pad), which is beneficial to ensure that the inner pad is exposed through the window to facilitate the probe to measure the inner layer circuit. However, for the millimeter wave products of the present application, since the inner pads are tiny pads, the size of the inner pads is usually between 0.1mm-0.4mm, and the diameter of the test probe used to detect the inner line capability is usually between 0.6mm-0.8mm. Therefore, the window size of the adhesive sheet will not be very large, and is usually roughly the same as the diameter of the test probe. After lamination, the overflow of the adhesive sheet will fill the window position, causing the inner pads to be covered by PP glue. Therefore, in order to expose the inner pads, CNC milling or laser burning technology (or other methods) is still required to remove the PP glue above the inner pads, so there is also a risk of damaging the inner pads.

[0041] Based on this, the present application provides a method for manufacturing a circuit board, which solves the problem of damage to the inner layer pads by covering the inner layer pads with protective ink to protect the inner layer pads when removing the medium above the inner layer pads.

[0042] At the same time, considering that after the protective ink is covered on the inner layer pad, the protective ink will bulge on the surface of the inner layer board, causing the circuit board to bulge at the position corresponding to the inner layer pad after lamination, making it impossible for the circuit board to maintain a flat surface. Based on this, the circuit board and its manufacturing method provided by the present application, by opening a window on the adhesive sheet in advance, the adhesive sheet can reserve space for the protective ink, so that the circuit board can maintain a flat surface after lamination, which is beneficial to improving the reliability of the circuit board.

[0043] In addition, the present application also provides a circuit board manufactured using the circuit board manufacturing method.

[0044] The contents of the present application are described in detail below in conjunction with specific embodiments and drawings. It should be noted that the following description is only for illustrative purposes and is not a specific limitation to the present application.

[0045] Reference Figure 1 , and combined with Figures 2 to 6 The circuit board 1 embodiment shown, the method for manufacturing the circuit board 1 of the embodiment of the present application comprises the following steps:

[0046] S100 , providing an inner layer board 10 , an adhesive sheet 20 and an outer layer board 30 , wherein the inner layer board 10 is provided with an inner layer pad 101 , and the adhesive sheet 20 is provided with a window portion 201 .

[0047] S200 , covering the inner layer pad 101 with protective ink 40 .

[0048] S300 , stack the adhesive sheet 20 between the inner layer board 10 and the outer layer board 30 so that the inner layer pad 101 is located in the window portion 201 , and laminate the inner layer board 10 , the adhesive sheet 20 and the outer layer board 30 so that the PP glue 202 overflowing from the adhesive sheet 20 fills the window portion 201 .

[0049] S400 , removing the area of ​​the outer layer board 30 corresponding to the inner layer pad 101 .

[0050] S500, remove the PP glue 202 on the window part.

[0051] S600, removing the protective ink 40.

[0052] It can be seen that the method for manufacturing the circuit board 1 provided in the embodiment of the present application covers the inner pad 101 with the protective ink 40 to isolate the adhesive sheet 20 from the inner pad 101 during lamination, which is beneficial to protecting the inner pad 101 when removing the adhesive sheet 20 or the PP glue 202, thereby ensuring that the inner pad 101 will not be damaged when the medium above the inner pad 101 is removed, thereby improving the safety of the inner pad 101. Finally, the protective ink 40 is removed to expose the inner pad 101, so as to achieve the exposure of the inner pad 101, thereby The design requirement of exposing the inner layer pad 101 while ensuring the safety of the inner layer pad 101 is met. At the same time, by opening a window in the adhesive sheet 20 in advance, and the window portion 201 is arranged corresponding to the protective ink 40, space can be reserved for the protective ink 40, so that the surface of the circuit board 1 remains flat after lamination, so as to improve the reliability of the circuit board 1, and effectively avoid the situation where the circuit board 1 bulges at the position corresponding to the inner layer pad 101 due to covering the inner layer pad 101 with the protective ink 40, thereby affecting the production and operation of the circuit board 1.

[0053] In some embodiments, considering that the adhesive sheet 20 usually includes epoxy resin and glass fiber, and the glass fiber has high mechanical strength, the difficulty of removing the adhesive sheet 20 is increased due to the influence of the glass fiber. Based on this, the window portion 201 penetrates the two side surfaces of the adhesive sheet 20. Therefore, on the one hand, after lamination, the upper part of the inner pad 101 is sequentially covered with the protective ink 40, the PP glue 202 and the outer layer board 30 without the glass fiber component, so that the PP glue 202 can be exposed after the area of ​​the inner pad 101 corresponding to the outer layer board 30 is removed in step S500, so as to facilitate the removal of the PP glue 202. On the other hand, compared with the design in which the window portion 201 does not penetrate the two sides of the adhesive sheet 20, the step of opening the cover of the adhesive sheet 20 can be saved, so that the circuit board 1 only needs The inner pad 101 can be exposed by removing the outer plate 30, the PP glue 202 and the protective ink 40, which is conducive to simplifying the operation steps of exposing the inner pad 101 and reducing the difficulty of manufacturing the circuit board 1. At the same time, after removing the area of ​​the outer plate 30 corresponding to the inner pad 101, there is only one component of epoxy resin above the protective ink 40, which can be conducive to the removal of the PP glue 202, so that the removal of the PP glue 202 in step S500 is more uniform and thorough, which is conducive to the exposure of the inner pad 101. In addition, by setting the window part 201 to penetrate the two opposite sides of the adhesive sheet 20, sufficient space can be reserved for the protective ink 40, reducing the thickness limit of the protective ink 40, reducing the difficulty of manufacturing the circuit board 1, and helping the circuit board 1 to keep the surface flat after lamination, so as to improve the reliability of the circuit board 1.

[0054] It can be understood that in some other embodiments, the window portion 201 may also be a groove opening toward the inner plate 10 .

[0055] Optionally, the above step S100 also includes the production of the inner layer circuit 102, which specifically includes sequentially processing the inner layer board 10 with the following steps: dry film pasting, exposure, development, etching, dry film removal, and circuit optical inspection (AOI, the full name of which is Automated Optical Inspection, also known as automatic optical inspection).

[0056] In some embodiments, considering that the main component of the PP glue 202 is epoxy resin, when the bonding strength between the protective ink 40 and the PP glue 202 is insufficient, voids or delamination problems may occur between the protective ink 40 and the PP glue 202. After the high-temperature treatment process, the bonding strength between adjacent board layers will decrease, affecting the interlayer reliability of the product and thus affecting the quality of the product. Based on this, the material of the protective ink 40 includes epoxy resin, and the protective ink 40 is bonded to the PP glue 202 after lamination.

[0057] In this way, the epoxy resin component of the protective ink 40 is the same as or similar to the material of the PP glue 202. After being subjected to high temperature and high pressure, the two can be firmly combined to improve the bonding strength between the protective ink 40 and the PP glue 202, which is beneficial to ensure the reliability of the product before removing the PP glue 202 and avoid stratification between the two materials after the product has undergone a high-temperature treatment process.

[0058] Exemplarily, the protective ink 40 can be an anti-etching ink, whose main components include ultraviolet sensitive components, epoxy resin and curing agent. Compared with the dry film, the film layer of the anti-etching ink will not become fuzzy, warped or fall off, and the epoxy resin component of the anti-etching ink is consistent with the epoxy resin component in the PP glue 202, which can help improve the reliability of the combination of the anti-etching ink and the PP glue 202. In addition, the anti-etching ink does not require exposure treatment and can be cured after baking. The anti-etching ink can be removed using sodium hydroxide stripping solution, so that the curing and removal methods of the anti-etching ink are simpler, which is helpful to simplify the operation steps of exposing the inner layer pad 101 and reduce the difficulty of manufacturing the circuit board 1.

[0059] Optionally, the area of ​​the protective ink 40 is greater than or equal to the area of ​​the inner pad 101 , so as to ensure the safety of the inner pad 101 .

[0060] Optionally, the cross-sectional area of ​​the window portion 201 is greater than or equal to the area of ​​the protective ink 40 , thereby facilitating the removal of the protective ink 40 while ensuring that the inner layer pad 101 can be completely exposed.

[0061] Optionally, the protective ink 40 may be covered by any one of silk-screen printing, spraying or embossing, etc., which may be set according to actual needs and is not limited here.

[0062] In some embodiments, the area of ​​the outer layer board 30 corresponding to the inner layer pad 101 is removed during the process of manufacturing the circuit (i.e., the outer layer circuit) of the outer layer board 30, that is, the area of ​​the outer layer board 30 corresponding to the inner layer pad 101 is removed by manufacturing the outer layer circuit. Thus, the manufacturing process can be reasonably utilized, and the outer layer board 30 can be opened during the process of manufacturing the outer layer circuit, which is conducive to improving the manufacturing efficiency of the circuit board 1.

[0063] Optionally, the production of the outer layer circuit specifically includes the following steps in sequence: dry film pasting, exposure, development, etching, dry film stripping, and circuit optical inspection. Among them, the dry film stripping step uses sodium hydroxide stripping liquid to strip.

[0064] Optionally, the protective ink 40 is removed by using the film stripping section for making the pattern of the outer layer board 30, that is, the protective ink 40 is removed by using the film stripping process for making the circuit of the outer layer board 30, so as to reasonably utilize materials and improve the reuse rate of the manufacturing process.

[0065] It should be noted that, although the protective ink 40 is removed in the above-mentioned step S600 by utilizing the film stripping process for manufacturing the circuit of the outer layer board 30, it does not mean that it is removed during the process of manufacturing the circuit of the outer layer board 30. In fact, step S600 is performed after step S400 and step S500, that is to say, the circuit of the outer layer board 30 is first manufactured to remove the area of ​​the outer layer board 30 corresponding to the inner layer pad 101, and then the PP glue 202 in the window part is removed, and finally the product is returned to the film stripping section to remove the protective ink 40.

[0066] It is understandable that in other embodiments, the protective ink 40 may also be removed by other means, such as dripping sodium hydroxide stripping solution or other chemical agents on the protective ink 40 .

[0067] In some embodiments, the manufacturing method of the circuit board 1 of the embodiment of the present application uses a laser depth control process to remove the PP glue 202 in the window part. This can help control the travel depth of the drill, so that the PP glue 202 in the window part is completely removed to expose the inner pad 101, so as to ensure the ability to measure the inner circuit 102 of the finished product.

[0068] Optionally, considering that the PP glue 202 and the protective ink 40 are firmly combined after the high temperature and high pressure process, based on this, when the PP glue 202 in the window is removed by the laser depth control process, the drill is controlled to move to contact the protective ink 40. In this way, it can ensure that the PP glue 202 in the window can be completely removed, so that only the protective ink 40 remains on the inner pad 101, so that the inner pad 101 can be completely exposed after the protective ink 40 is removed, so as to ensure the ability to measure the inner circuit 102 of the finished product of the circuit board 1, and the protective ink 40 can be used to protect the inner pad 101, so as to avoid the inner pad 101 from being damaged when the PP glue 202 is removed.

[0069] It is understandable that in other embodiments, the PP glue 202 in the window portion can also be removed by chemical agents (such as alcohol, acetic acid or sodium hydroxide, etc.) or manual removal (such as pulling out after heating and softening or digging out after solidification).

[0070] In some embodiments, the size of the inner pad 101 is 0.1 mm-0.4 mm, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm or 0.4 mm, etc. That is, the inner pad 101 of the embodiment of the present application is a tiny pad, based on which the protective ink 40 uses an anti-etching ink, which can be applied to a single tiny pad to protect the single tiny inner pad 101.

[0071] As can be seen from the above, the size of the inner pad 101 is 0.1-0.4mm, so the diameter of the test probe used to detect the capability of the inner layer circuit 102 is usually between 0.6mm-0.8mm, and the size of the window of the adhesive sheet 20 is usually consistent with the test probe, that is, the size of the window is between 0.6mm-0.8mm. Based on this, in order to avoid the problem of lack of glue or excessive overflow of glue in the window, in some embodiments, the thickness of the adhesive sheet 20 is 60um-160mm, for example, it can be 60um, 65um, 70um, 80um, 100um, 120um, 150um or 160um, etc. Therefore, on one hand, it can ensure that the adhesive sheet 20 has a sufficiently large thickness so that the PP glue 202 overflowing from the adhesive sheet 20 during lamination can fill the window portion, thereby avoiding the situation where the reliability of the product layers is affected due to lack of glue in the window portion. On the other hand, it can ensure the amount of glue overflowing from the adhesive sheet 20 during lamination, thereby avoiding the situation where too much PP glue 202 overflows from the adhesive sheet 20, resulting in the PP glue 202 overflowing from the window portion.

[0072] Optionally, the RC content (i.e., Resin Content) in the adhesive sheet 20 is 60%-80%, for example, 60%, 65%, 70%, 75% or 80%, etc. This ensures that the amount of adhesive overflowing from the adhesive sheet 20 during lamination can fill the window portion, while preventing the PP adhesive 202 from overflowing the window portion.

[0073] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for manufacturing a circuit board, characterized in that: include: Providing an inner layer board, an adhesive sheet and an outer layer board, wherein the inner layer board is provided with an inner layer pad, and the adhesive sheet is provided with a window portion; Covering the inner pad with protective ink; The adhesive sheet is stacked between the inner layer board and the outer layer board so that the inner layer pad is located in the window portion, and the inner layer board, the adhesive sheet and the outer layer board are laminated so that the PP glue overflowing from the adhesive sheet fills the window portion; Removing the area of ​​the outer layer board corresponding to the inner layer pad; Remove the PP glue from the window; The protective ink is removed.

2. The method for manufacturing a circuit board according to claim 1, characterized in that: The PP glue on the window portion is removed by using a laser depth control process.

3. The method for manufacturing a circuit board according to claim 2, characterized in that: When the laser depth control process is used to remove the PP glue on the window portion, the drill is controlled to move until it contacts the protective ink.

4. The method for manufacturing a circuit board according to claim 1, characterized in that: The window portion penetrates through both side surfaces of the adhesive sheet.

5. The method for manufacturing a circuit board according to claim 1, characterized in that: The material of the protective ink includes epoxy resin, and the protective ink is combined with the PP glue after lamination.

6. The method for manufacturing a circuit board according to claim 5, characterized in that: The protective ink is removed by using the film stripping section of the circuit for making the outer layer board.

7. The method for manufacturing a circuit board according to claim 1, characterized in that: During the circuit manufacturing process of the outer layer board, the area of ​​the outer layer board corresponding to the inner layer pad is removed.

8. The method for manufacturing a circuit board according to claim 1, characterized in that: The size of the inner pad is 0.1mm-0.4mm.

9. The method for manufacturing a circuit board according to claim 8, characterized in that: The thickness of the adhesive sheet is 60um-160mm, and / or the RC content of the adhesive sheet is 60%-80%.

10. A circuit board, characterized in that: The circuit board is manufactured by the method for manufacturing the circuit board as described in any one of claims 1 to 9.

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