Printed circuit board and method for manufacturing the same

Abstract

The application discloses a printed circuit board and a preparation method thereof. The preparation method of the printed circuit board comprises the following steps: obtaining a processing plate, wherein the processing plate comprises a first conductive layer, a first insulating layer, a dielectric layer, a second insulating layer and a second conductive layer which are sequentially stacked and attached; drilling a preset position of the first conductive layer of the processing plate according to a first drilling range, and drilling through the first conductive layer and the first insulating layer to expose part of the dielectric layer; drilling the exposed part of the dielectric layer according to a second drilling range, and drilling through the dielectric layer to prepare the printed circuit board; and the second drilling range is smaller than the first drilling range. Through the above method, the application can reduce the phenomenon of concave holes during drilling of the circuit board, thereby ensuring signal transmission of the holes and improving the reliability of the printed circuit board.

Description

Technical Field

[0001] This invention applies to the technical field of printed circuit boards, particularly printed circuit boards and their preparation methods. Background Technology

[0002] PCB (Printed Circuit Board), also known as printed circuit board, is a widely used and important electronic component. It serves as the support for electronic components and the carrier for their electrical connections.

[0003] As printed circuit boards (PCBs) evolve towards higher frequencies and speeds, the requirements for their electrical performance and low losses are becoming increasingly stringent. Rigid foam dielectric materials possess excellent electrical insulation properties, with minimal variations in dielectric constant and dielectric loss, exhibiting excellent broadband stability and making them suitable for specialized products such as antennas, radar, and aerospace applications.

[0004] Because foam media materials are brittle, not resistant to high temperatures, and easily deformed, they are prone to indentation during drilling due to high temperatures, which affects the signal transmission and reliability of the hole. Summary of the Invention

[0005] This invention provides a printed circuit board and a method for preparing the same, in order to solve the problem that foam dielectric material is prone to concavity during the drilling process.

[0006] To address the aforementioned technical problems, the present invention provides a method for manufacturing a printed circuit board, comprising: obtaining a processing board, wherein the processing board includes at least a first conductive layer, a first insulating layer, a dielectric layer, a second insulating layer, and a second conductive layer sequentially stacked and bonded together; drilling holes in a predetermined position of the first conductive layer of the processing board according to a first drilling range, and drilling through the first conductive layer and the first insulating layer to expose a portion of the dielectric layer; drilling holes in the exposed portion of the dielectric layer according to a second drilling range, and drilling through the dielectric layer to prepare a printed circuit board; wherein the second drilling range is smaller than the first drilling range.

[0007] The second drilling range is obtained by subtracting the first drilling range from twice the preset shrinkage range; the preset shrinkage distance is the thermal shrinkage distance of the medium layer.

[0008] The step of drilling holes in a predetermined position of the first conductive layer of the processed board according to a first drilling range, and drilling through the first conductive layer and the first insulating layer to expose a portion of the dielectric layer includes: using a first drill bit to drill holes in a predetermined position of the first conductive layer of the processed board according to a first drilling range, and drilling through the first conductive layer and the first insulating layer to expose a portion of the dielectric layer; and drilling holes in the exposed portion of the dielectric layer according to a second drilling range, and drilling through the dielectric layer to prepare a printed circuit board includes: using a second drill bit to drill holes in the exposed portion of the dielectric layer according to a second drilling range, and drilling through the dielectric layer to prepare a printed circuit board; wherein the diameter of the second drill bit is smaller than that of the first drill bit.

[0009] The step of drilling holes in the first conductive layer of the processed board at a predetermined position according to the first drilling range, and drilling through the first conductive layer and the first insulating layer to expose a portion of the dielectric layer, further includes: drilling holes in the first conductive layer of the processed board at a predetermined position according to the first drilling range, and drilling through the first conductive layer and the first insulating layer to expose a portion of the dielectric layer; and drilling holes in the second conductive layer and the second insulating layer on the processed board corresponding to the predetermined position according to the first drilling range, until the other side of the portion of the dielectric layer is exposed.

[0010] The step of drilling the dielectric layer of the exposed portion according to the second drilling range and drilling through the dielectric layer to prepare a printed circuit board includes: drilling the dielectric layer and the corresponding second insulating layer of the exposed portion according to the second drilling range until the second conductive layer of the exposed portion is exposed to prepare a printed circuit board.

[0011] The dielectric layer includes a polymethacrylimide layer.

[0012] The step of drilling the dielectric layer of the exposed portion according to the second drilling range and drilling through the dielectric layer includes: performing copper plating on the drilled processing board to metallize the processing board; performing pattern transfer processing on the conductive layer on the metallized processing board to prepare conductive lines; and performing surface treatment on the processing board after pattern transfer processing to prepare a printed circuit board.

[0013] The step of performing pattern transfer processing on the conductive layer on the metallized processing board to prepare conductive lines includes: partially covering the surface of the conductive layer on the metallized processing board with an anti-corrosion film; etching the metallized processing board to form conductive lines; and removing the anti-corrosion film.

[0014] The step of performing surface treatment on the processed board after pattern transfer to prepare a printed circuit board includes: coating the surface of the processed board after pattern transfer with ink and / or electroplating nickel and gold to complete the surface treatment.

[0015] To solve the above-mentioned technical problems, the present invention also provides a printed circuit board prepared by any of the above-mentioned printed circuit board preparation methods.

[0016] The beneficial effects of this invention are as follows: Unlike existing technologies, this invention first obtains a processing board, then drills holes in a predetermined position of the first conductive layer of the processing board according to a first drilling range, penetrating both the first conductive layer and the first insulating layer to expose a portion of the dielectric layer. Then, it drills holes in the exposed portion of the dielectric layer according to a second drilling range, penetrating the dielectric layer, to prepare a printed circuit board. This process divides the drilling steps into at least two stages. First, holes of normal diameter are prepared in the conductive and insulating layers through a single drilling operation. Then, holes in the dielectric layer are drilled separately through a second drilling range smaller than the first drilling range, reserving space for thermal shrinkage of the dielectric layer. This ensures that even if the holes formed in the dielectric layer shrink due to heat, the holes will not become concave. Consequently, the diameter of the holes formed in the dielectric layer by the second drilling operation is close to that of the holes formed in the conductive and insulating layers by the first drilling operation, improving the flatness of the inner wall of the holes and thus ensuring signal transmission and improving the reliability of the printed circuit board. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of an embodiment of the printed circuit board manufacturing method provided by the present invention;

[0018] Figure 2 This is a schematic flowchart of another embodiment of the printed circuit board manufacturing method provided by the present invention;

[0019] Figure 3 yes Figure 2 A schematic diagram of the structure of one embodiment of the processed plate in step S22 of the example;

[0020] Figure 4 yes Figure 2 A schematic diagram of the structure of one embodiment of the processed plate in step S23 of the example;

[0021] Figure 5 This is a schematic flowchart of another embodiment of the printed circuit board manufacturing method provided by the present invention;

[0022] Figure 6 yes Figure 5 A schematic diagram of the structure of one embodiment of the processed plate in step S33 of the example;

[0023] Figure 7 This is a schematic diagram of a printed circuit board according to an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0026] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0027] Please see Figure 1 , Figure 1 This is a schematic flowchart of an embodiment of the printed circuit board manufacturing method provided by the present invention.

[0028] Step S11: Obtain the processing board, wherein the processing board includes at least a first conductive layer, a first insulating layer, a dielectric layer, a second insulating layer and a second conductive layer that are stacked and bonded together in sequence.

[0029] A processing board is obtained, wherein the processing board includes at least a first conductive layer, a first insulating layer, a dielectric layer, a second insulating layer, and a second conductive layer that are sequentially stacked and bonded together.

[0030] In this embodiment, the first conductive layer, the first insulating layer, the dielectric layer, the second insulating layer, and the second conductive layer, which are sequentially stacked and bonded together, constitute the smallest processing unit of the processed board. In one specific application scenario, the processed board may have at least one additional insulating layer and at least one additional conductive layer added to at least one side of the smallest processing unit. In another specific application scenario, the processed board may have at least one additional insulating layer and at least one other smallest processing unit added to at least one side of the smallest processing unit. The specific structure of the processed board is not limited here.

[0031] In this embodiment, the insulating layer may include one or more of the following: epoxy resin, polyimide, bismaleimide triazine (BT), and ceramic matrix. The specific material is not limited herein.

[0032] The printed circuit board in this embodiment may include an antenna board, which is suitable for special products such as antenna radar and aerospace, while the dielectric layer may be a foam dielectric to excite or induce electromagnetic waves.

[0033] Step S12: Drill holes at the preset positions of the first conductive layer of the processing board according to the first drilling range, and drill through the first conductive layer and the first insulating layer to expose part of the dielectric layer.

[0034] This embodiment requires creating at least one hole penetrating the dielectric layer on the processed board. First, drilling is performed at a predetermined position in the first conductive layer according to a first drilling range, penetrating both the first conductive layer and the first insulating layer to expose a portion of the dielectric layer. The predetermined position is the location in the first conductive layer where the hole needs to be created. In this step, the drilling only exposes a portion of the dielectric layer; it does not actually drill through the entire dielectric layer.

[0035] In this embodiment, the first conductive layer and the first insulating layer are first drilled through according to the first drilling range, thereby creating a hole with the size of the first drilling range in the first conductive layer and the first insulating layer. That is, the first drilling range is the range of hole diameters required to be prepared for processing the plate.

[0036] In a specific application scenario, drilling can be performed at a preset position of the first conductive layer by means of mechanical depth control or mechanical drilling, and the drilling can penetrate the first conductive layer and the first insulating layer to expose part of the dielectric layer.

[0037] In another specific application scenario, drilling can also be performed by laser drilling to drill through a preset position of the first conductive layer and the first insulating layer, thereby exposing part of the dielectric layer.

[0038] Step S13: Drill holes in the exposed dielectric layer according to the second drilling range, and drill through the dielectric layer to prepare a printed circuit board.

[0039] After exposing part of the dielectric layer, holes are drilled through the exposed portion of the dielectric layer according to the second drilling range, thereby creating holes in the dielectric layer to fabricate a printed circuit board. The second drilling range is smaller than the first drilling range.

[0040] In a specific application scenario, drilling can be performed on the exposed medium layer through mechanical depth control or mechanical drilling, and the medium layer can be drilled through.

[0041] In another specific application scenario, drilling can also be performed by using laser drilling to drill through the exposed dielectric layer.

[0042] Since mechanical drilling and laser drilling can generate temperatures exceeding 500 degrees Celsius during the drilling process, the dielectric layer in this embodiment is susceptible to thermal shrinkage due to the high temperature. Therefore, this embodiment divides the drilling process into at least two steps, drilling the dielectric layer separately using a second drilling range smaller than the first drilling range. This allows space for the dielectric layer to shrink due to heat, ensuring that even if the hole formed on the dielectric layer shrinks due to heat, the hole will not become concave. Consequently, the diameter of the hole formed by the second drilling on the dielectric layer is close to that of the hole formed by the first drilling on the first conductive layer and the first insulating layer, improving the flatness of the hole's inner wall, thereby ensuring signal transmission and improving the reliability of the printed circuit board.

[0043] By drilling at least twice, this embodiment obtains a hole that penetrates at least the first conductive layer, the first insulating layer, and the dielectric layer for subsequent fabrication of the printed circuit board. After the subsequent fabrication of the printed circuit board is completed, the printed circuit board of this embodiment is obtained.

[0044] Through the above steps, the printed circuit board manufacturing method of this embodiment first obtains a processing board, then drills holes in the first conductive layer of the processing board at a preset position according to the first drilling range, and drills through the first conductive layer and the first insulating layer to expose a portion of the dielectric layer, and drills through the exposed portion of the dielectric layer according to the second drilling range to prepare the printed circuit board. By dividing the drilling step into at least two steps, firstly, holes of normal diameter are prepared on the conductive layer and the insulating layer through a first drilling, and then holes are drilled separately on the dielectric layer through a second drilling range smaller than the first drilling range, so as to reserve space for the dielectric layer to shrink inward when heated. This ensures that even if the holes formed on the dielectric layer shrink due to heat, the holes will not become concave. As a result, the diameter of the holes formed on the dielectric layer by the second drilling is close to that of the holes formed on the conductive layer and the insulating layer by the first drilling, improving the flatness of the inner wall of the hole, thereby ensuring the signal transmission of the hole and improving the reliability of the printed circuit board.

[0045] Please see Figure 2 , Figure 2 This is a schematic flowchart of another embodiment of the printed circuit board fabrication method provided by the present invention. The fabrication method of this embodiment is applicable to the fabrication of through holes.

[0046] Step S21: Obtain the processing board, wherein the processing board includes at least a first conductive layer, a first insulating layer, a dielectric layer, a second insulating layer and a second conductive layer that are stacked and bonded together in sequence.

[0047] This step obtains at least a first conductive layer, a first insulating layer, a dielectric layer, a second insulating layer, and a second conductive layer. The first conductive layer, the first insulating layer, the dielectric layer, the second insulating layer, and the second conductive layer are stacked in sequence. The stacked first conductive layer, the first insulating layer, the dielectric layer, the second insulating layer, and the second conductive layer are then pressed together to obtain the processed board.

[0048] In this embodiment, the first conductive layer, the first insulating layer, the dielectric layer, the second insulating layer, and the second conductive layer, which are sequentially stacked and bonded together, constitute the smallest processing unit of the processed board. In one specific application scenario, the processed board may have at least one additional insulating layer and at least one additional conductive layer added to at least one side of the smallest processing unit. In another specific application scenario, the processed board may have at least one additional insulating layer and at least one other smallest processing unit added to at least one side of the smallest processing unit. The specific structure of the processed board is not limited here.

[0049] Step S22: Using the first drill bit, drill holes in the preset position of the first conductive layer of the workpiece according to the first drilling range, and drill through the first conductive layer and the first insulating layer to expose part of the dielectric layer.

[0050] After obtaining the workpiece, a first drill bit is used to drill holes at preset positions of the first conductive layer of the workpiece according to a first drilling range, penetrating both the first conductive layer and the first insulating layer to expose a portion of the dielectric layer. The first drilling range refers to the diameter range of the holes to be prepared in the workpiece.

[0051] This step first involves drilling a hole of the first conductive layer and the first insulating layer of the workpiece to create a hole of the first drilling range size.

[0052] Please see Figure 3 , Figure 3 yes Figure 2 A schematic diagram of the structure of one embodiment of processing the plate in step S22 of the example.

[0053] This embodiment uses a processing board 100 as an example, which includes a first conductive layer 101, a first insulating layer 102, a dielectric layer 103, a second insulating layer 104, and a second conductive layer 105 that are stacked and bonded together in sequence. In other embodiments, the processing board 100 may also include other stacking methods, which are not limited here.

[0054] In this embodiment, the hole 106 penetrates the first conductive layer 101 and the first insulating layer 102, exposing a portion of the dielectric layer 103. The diameter of the hole 106 is the same as the first drilling range. The number of holes 106 can be multiple or one.

[0055] Step S23: Drill holes in the second conductive layer and the second insulating layer on the processing board corresponding to the preset position according to the first drilling range until the other side of part of the dielectric layer is exposed.

[0056] Drill holes in the second conductive layer and the second insulating layer on the workpiece at the preset positions according to the first drilling range until the other side of a portion of the dielectric layer is exposed. A hole exposing the other side of the dielectric layer is then created at the same position on the reverse side of the workpiece through secondary drilling, wherein the diameter of the hole is also within the first drilling range.

[0057] The steps of drilling the second conductive layer and the second insulating layer need to be performed before drilling the dielectric layer to avoid the temperature generated by this drilling causing the dielectric layer to shrink again and affecting the smoothness inside the through hole.

[0058] Please see Figure 4 , Figure 4 yes Figure 2 A schematic diagram of the structure of one embodiment of processing the plate in step S23 of the example.

[0059] In this embodiment, the second conductive layer 105 and the second insulating layer 104 of the processed plate 100 are provided with holes 107 corresponding to the holes 106 on the first conductive layer 101 and the first insulating layer 102, so as to expose the other side of a portion of the dielectric layer 103. The diameter of the hole 107 is the same as the diameter of the hole 106.

[0060] Step S24: Use the second drill bit to drill through the exposed medium layer according to the second drilling range.

[0061] The second drill bit is used to drill through the exposed medium layer according to the second drilling range, thereby penetrating the entire plate and forming the required through hole.

[0062] The second drilling range is smaller than the first drilling range. Specifically, the second drilling range is obtained by subtracting the first drilling range from twice the preset shrinkage range. The preset shrinkage distance is the thermal shrinkage distance of the medium layer, which can be obtained in advance by drilling the medium layer or calculated based on the physical parameters of the medium layer.

[0063] This embodiment, by pre-setting a preset shrinkage range of twice the size of the second drilling range, can reserve an accurate dielectric layer allowance. This ensures that the dielectric layer, after being affected by high temperature and undergoing thermal shrinkage, produces a hole diameter that is the same as the first drilling range. This results in a smooth inner wall of the entire through hole, thereby ensuring signal transmission and improving the reliability of the printed circuit board.

[0064] Furthermore, in this embodiment, the diameter of the second drill bit is smaller than that of the first drill bit, thereby improving the precision and accuracy of the drilling through the smaller second drill bit, further improving the flatness of the inner wall of the entire through hole, ensuring signal transmission through the hole, and improving the reliability of the printed circuit board.

[0065] In this embodiment, the dielectric material of the dielectric layer is polymethacrylimide, which has good electrical insulation properties, a dielectric constant of 1.05 to 1.13, a dielectric loss of 0.001 to 0.0018, and very small variations in DK and Df, exhibiting excellent broadband stability.

[0066] Step S25: Perform copper plating on the drilled board to metallize it; perform pattern transfer processing on the conductive layer on the metallized board to create conductive lines; perform surface treatment on the board after pattern transfer processing to obtain a printed circuit board.

[0067] After drilling through holes in the processed board, the board can be subjected to copper plating to metallize it, thereby forming metallized holes to achieve interconnection between boards.

[0068] Next, the conductive layer on the metallized processing board is subjected to pattern transfer processing to create conductive lines and realize the function of the circuit board. Specifically, a resist film can be partially covered on the surface of the conductive layer on the metallized processing board; the metallized processing board is etched to form conductive lines; and the resist film is removed.

[0069] Finally, the processed board after pattern transfer is subjected to surface treatment to obtain a printed circuit board. Specifically, ink and / or nickel-gold plating can be applied to the surface of the processed board after pattern transfer, followed by surface cleaning and drying to complete the surface treatment.

[0070] Through the above steps, the printed circuit board fabrication method of this embodiment breaks down the preparation of through-holes into three drilling operations. First, the first conductive layer and the first insulating layer are drilled through according to the first drilling range. Then, the second conductive layer and the second insulating layer are drilled through according to the first drilling range. Finally, the exposed dielectric layer is drilled through according to the second drilling range using a second drill bit, thereby obtaining the through-hole. This embodiment reserves space for the dielectric layer to shrink due to heat during the three drilling operations, so that even if the hole formed on the dielectric layer shrinks due to heat, the hole will not become concave. This ensures that the hole formed by the three drilling operations on the dielectric layer has the same diameter as the holes formed by the first and second drilling operations on the conductive and insulating layers, improving the flatness of the hole's inner wall, thereby ensuring signal transmission and improving the reliability of the printed circuit board.

[0071] Please see Figure 5 , Figure 5 This is a schematic flowchart of another embodiment of the printed circuit board fabrication method provided by the present invention. The fabrication method of this embodiment is applicable to the fabrication of blind vias.

[0072] Step S31: Obtain the processing board, wherein the processing board includes at least a first conductive layer, a first insulating layer, a dielectric layer, a second insulating layer and a second conductive layer that are stacked and bonded together in sequence.

[0073] This step is similar to step S21 in the previous embodiment, as described above, and will not be repeated here.

[0074] Step S32: Drill holes at the preset positions of the first conductive layer of the processing board according to the first drilling range, and drill through the first conductive layer and the first insulating layer to expose part of the dielectric layer.

[0075] After obtaining the workpiece, a first drill bit is used to drill holes at preset positions of the first conductive layer of the workpiece according to a first drilling range, penetrating both the first conductive layer and the first insulating layer to expose a portion of the dielectric layer. The first drilling range refers to the diameter range of the holes to be prepared in the workpiece.

[0076] This step first involves drilling a hole of the first conductive layer and the first insulating layer of the workpiece to create a hole of the first drilling range size.

[0077] The structural diagram of the processed plate in this embodiment is shown below. Figure 3 Same, please see Figure 3 .

[0078] Step S33: Drill holes in the exposed dielectric layer and the corresponding second insulating layer according to the second drilling range until the exposed second conductive layer is exposed.

[0079] Using a second drill bit, holes are drilled through the exposed dielectric layer and the corresponding second insulating layer within the second drilling range, penetrating the dielectric layer to completely pierce the entire board and form the required blind hole. Since the blind hole needs to achieve conductivity between different conductive layers, the second insulating layer also needs to be drilled through during this drilling process.

[0080] In this embodiment, the dielectric material of the dielectric layer is polymethacrylimide, which has good electrical insulation properties, a dielectric constant of 1.05 to 1.13, a dielectric loss of 0.001 to 0.0018, and very small variations in DK and Df, exhibiting excellent broadband stability.

[0081] Please see Figure 6 , Figure 6 yes Figure 5A schematic diagram of the structure of one embodiment of processing the plate in step S33 of the example.

[0082] The processing board 200 in this embodiment includes a first conductive layer 201, a first insulating layer 202, a dielectric layer 203, a second insulating layer 204, and a second conductive layer 205, which are stacked and bonded together in sequence. A blind hole 206 is provided on the processing board 200, which penetrates the first conductive layer 201, the first insulating layer 202, the dielectric layer 203, and the second insulating layer 204, and exposes the second conductive layer 205.

[0083] Specifically, the diameter of the blind hole 206 at the second insulating layer 204 is smaller than the diameter of the holes in other layers. Specifically, the diameter of the blind hole 206 at the second insulating layer 204 is within the second drilling range, while the diameter of the blind hole 206 in other layers is within the first drilling range.

[0084] Step S34: Perform copper plating on the drilled board to metallize it; perform pattern transfer processing on the conductive layer on the metallized board to create conductive lines; perform surface treatment on the board after pattern transfer processing to obtain a printed circuit board.

[0085] This step is similar to step S25 in the previous embodiment, as described above, and will not be repeated here.

[0086] Through the above steps, the printed circuit board fabrication method of this embodiment breaks down the fabrication of blind vias into two drilling operations. First, the first conductive layer and the first insulating layer are drilled through according to the first drilling range. Then, a second drill bit is used to drill through the exposed dielectric layer and the second insulating layer according to the second drilling range, thereby creating a through-hole. This embodiment reserves space for the dielectric layer to shrink due to heat during the second drilling, so that even if the hole formed on the dielectric layer shrinks due to heat, the hole will not become concave. This makes the diameter of the hole formed on the dielectric layer by the second drilling close to that of the hole formed on the conductive and insulating layers by the first drilling, improving the flatness of the inner wall of the hole, thereby ensuring signal transmission through the hole and improving the reliability of the printed circuit board.

[0087] Please see Figure 7 , Figure 7 This is a schematic diagram of a printed circuit board according to an embodiment of the present invention. This embodiment is illustrated by taking the simultaneous provision of blind vias and through vias on the printed circuit board as an example. In other embodiments, the printed circuit board may only have blind vias or through vias, which is not limited here.

[0088] The printed circuit board 300 of this embodiment includes at least a first solder mask layer 308, a first circuit layer 301, a first insulating layer 302, a dielectric layer 303, a second insulating layer 304, a second circuit layer 305, and a second solder mask layer 309, which are stacked and bonded together in sequence.

[0089] The printed circuit board 300 is provided with metallized blind vias 306 and metallized through vias 307. The metallized blind via 306 penetrates the first solder mask layer 308, the first circuit layer 301, the first insulating layer 302, the dielectric layer 303, and the second insulating layer 304, and exposes the second circuit layer 305. The diameter of the metallized blind via 306 at the second insulating layer 304 is smaller than the diameters at other layers. Specifically, the diameter of the metallized blind via 306 at the second insulating layer 304 is within the second drilling range, and the diameters of the metallized blind via 306 at other layers are within the first drilling range.

[0090] Metallized via 307 extends through the entire printed circuit board 300 to achieve board interconnection. The diameter of the metallized via 307 is within the first drilling range.

[0091] In this embodiment, the dielectric material of the dielectric layer 303 is polymethacrylimide, which has good electrical insulation properties, a dielectric constant of 1.05 to 1.13, a dielectric loss of 0.001 to 0.0018, and very small variations in DK and Df, exhibiting excellent broadband stability.

[0092] With the above structure, the printed circuit board of this embodiment can effectively use polymethacrylimide as the dielectric layer, avoid the occurrence of concave holes, ensure signal transmission through the holes, improve the reliability of the printed circuit board, and utilize polymethacrylimide to improve the broadband stability of the printed circuit board.

[0093] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method of manufacturing a printed circuit board, characterized by, The method for manufacturing the printed circuit board includes: A processed board is obtained, wherein the processed board includes at least a first conductive layer, a first insulating layer, a dielectric layer, a second insulating layer, and a second conductive layer that are sequentially stacked and bonded together; the dielectric layer includes a polymethacrylimide layer; Drill holes in the first conductive layer of the processed board at a predetermined position according to the first drilling range, and drill through the first conductive layer and the first insulating layer to expose part of the dielectric layer. The dielectric layer of the exposed portion is drilled according to the second drilling range, and the dielectric layer is drilled through to prepare the printed circuit board; Wherein, the second drilling range is smaller than the first drilling range, and the second drilling range is obtained by subtracting the first drilling range from twice the preset shrinkage range; wherein, the preset shrinkage range is the thermal shrinkage distance of the medium layer.

2. The method for preparing a printed circuit board according to claim 1, characterized in that, The step of drilling holes at predetermined positions of the first conductive layer of the processed board according to the first drilling range, and drilling through the first conductive layer and the first insulating layer to expose a portion of the dielectric layer includes: Using a first drill bit, a hole is drilled at a preset position of the first conductive layer of the processed plate according to the first drilling range, and the first conductive layer and the first insulating layer are drilled through to expose part of the dielectric layer. The step of drilling the exposed portion of the dielectric layer according to the second drilling range and drilling through the dielectric layer to prepare the printed circuit board includes: The dielectric layer of the exposed portion is drilled using a second drill bit according to the second drilling range, and the dielectric layer is drilled through to prepare the printed circuit board; The diameter of the second drill bit is smaller than that of the first drill bit.

3. The method for manufacturing a printed circuit board according to claim 1 or 2, characterized in that, The step of drilling holes at predetermined positions of the first conductive layer of the processed board according to the first drilling range, and drilling through the first conductive layer and the first insulating layer to expose a portion of the dielectric layer, further includes: Drill holes at predetermined positions in the first conductive layer of the processed board according to the first drilling range, penetrating both the first conductive layer and the first insulating layer to expose a portion of the dielectric layer; and Drill holes in the second conductive layer and the second insulating layer on the processing plate corresponding to the preset position according to the first drilling range until the other side of the portion of the dielectric layer is exposed.

4. The method for manufacturing a printed circuit board according to claim 1 or 2, characterized in that, The step of drilling the exposed portion of the dielectric layer according to the second drilling range and drilling through the dielectric layer to prepare the printed circuit board includes: Drill holes in the exposed portion of the dielectric layer and the corresponding second insulating layer according to the second drilling range until the exposed portion of the second conductive layer is exposed, in order to prepare the printed circuit board.

5. The method for preparing a printed circuit board according to claim 1, characterized in that, The step of drilling the exposed portion of the medium layer according to the second drilling range and drilling through the medium layer includes: The machined board after drilling is subjected to copper plating to metallize it. The conductive layer on the metallized processing board is subjected to pattern transfer processing to prepare conductive circuits; The surface of the processed board after pattern transfer is treated to prepare the printed circuit board.

6. The method for manufacturing a printed circuit board according to claim 5, characterized in that, The step of performing pattern transfer processing on the conductive layer on the metallized processing board to prepare conductive circuits includes: A corrosion-resistant film is partially covered on the surface of the conductive layer on the metallized workpiece. The metallized workpiece is etched to form the conductive lines; Remove the anti-corrosion film.

7. The method for manufacturing a printed circuit board according to claim 5, characterized in that, The step of performing surface treatment on the processed board after pattern transfer processing to prepare the printed circuit board includes: The surface of the processed plate after the graphic transfer process is coated with ink and / or electroplated with nickel-gold to complete the surface treatment.

8. A printed circuit board, characterized in that, The printed circuit board is prepared by the method for preparing a printed circuit board as described in any one of claims 1-7.

Images