Printed circuit board, manufacturing method thereof and electronic equipment

Abstract

The embodiment of the invention provides a printed circuit board, a manufacturing method thereof and electronic equipment, and relates to the technical field of printed circuit board manufacturing. The printed circuit board comprises a first circuit board and a second circuit board, the second circuit board comprises a first circuit layer, a first bonding layer, a first dielectric layer, a second bonding layer and a second circuit layer which are stacked, and the second circuit layer is connected with the first circuit board; the via hole penetrates through the second circuit layer, the second bonding layer, the first dielectric layer and the first bonding layer; and the first conductive part is arranged in the via hole, and the first conductive part is connected with the first circuit layer and the second circuit layer. According to the printed circuit board provided by the embodiment of the invention, a reversed-phase laser process is used, and when residues at the bottom of the hole are removed by laser ablation, heat generated by laser ablation is directly transferred to the external environment through the first circuit layer, so that the first circuit board is not separated from the second circuit layer.

Description

Technical Field

[0001] The present application relates to the technical field of printed circuit board manufacturing, and in particular to a printed circuit board, a manufacturing method thereof, and an electronic device. Background Art

[0002] High-Density Interconnect Printed Circuit Board (HDIPCB) uses vias to form a high-density interconnection structure, which can achieve more circuit connections and functional integration in a limited space, thereby realizing the miniaturization, lightweight and high performance of electronic equipment.

[0003] See also Figure 2 A printed circuit board is provided in the related technology, including: a first core board 10; a second core board 20, the second core board 20 includes a first copper foil layer 21, a first connecting layer 22, a substrate 23, a second connecting layer 24 and a second copper foil layer 25 stacked in sequence, and the second copper foil layer 25 is arranged on the first core board 10; the second core board 20 also includes a connecting hole 26 and a copper foil part 27, the connecting hole 26 passes through the second connecting layer 24, the substrate 23, the first connecting layer 22 and the first copper foil layer 21, the copper foil part 27 is arranged in the connecting hole 26, and the copper foil part 27 connects the first copper foil layer 21 and the second copper foil layer 25.

[0004] When the connection hole 26 is formed, part of the first connection layer 22 and part of the second connection layer 24 remain at the bottom of the connection hole 26 and need to be removed by laser ablation.

[0005] However, the heat generated by laser ablation is transferred to between the first core board 10 and the second copper foil layer 25 through the second copper foil layer 25 , which may easily cause the first core board 10 and the second copper foil layer 25 to separate. Summary of the Invention

[0006] The embodiments of the present application provide a printed circuit board, a manufacturing method thereof, and an electronic device to solve the problem that the heat generated by laser ablation is transferred between the first core board and the second copper foil layer through the second copper foil layer, which easily causes the first core board and the second copper foil layer to separate.

[0007] In a first aspect, an embodiment of the present application provides a printed circuit board, comprising a first circuit board and a second circuit board, wherein the second circuit board comprises:

[0008] A first circuit layer, a first adhesive layer, a first dielectric layer, a second adhesive layer, and a second circuit layer are stacked, wherein the second circuit layer is connected to the first circuit board;

[0009] a via hole, the via hole passing through the second circuit layer, the second bonding layer, the first dielectric layer and the first bonding layer;

[0010] The first conductive member is disposed in the via hole and connects the first circuit layer and the second circuit layer.

[0011] In a possible implementation manner, the radial width of the through hole gradually decreases from the hole opening to the hole bottom.

[0012] In a possible implementation, the via hole is a laser hole.

[0013] In a possible implementation manner, the first conductive member is a copper foil member.

[0014] In a possible implementation manner, the first dielectric layer is a polytetrafluoroethylene layer.

[0015] In a possible implementation, the second circuit board further includes a protective layer, which is detachably connected to a side of the first circuit layer facing away from the first adhesive layer.

[0016] In a possible implementation manner, the protective layer is a copper foil layer.

[0017] In one possible embodiment, the printed circuit board further includes a plurality of fourth adhesive layers;

[0018] There are multiple first circuit boards, and two adjacent first circuit boards are connected via a fourth adhesive layer.

[0019] In one possible embodiment, the printed circuit board further includes a third adhesive layer;

[0020] The first circuit board includes a second dielectric layer and two third circuit layers respectively arranged on both sides of the second dielectric layer. The second circuit layer is connected to the third circuit layer located on the outer layer through a third adhesive layer.

[0021] In one possible implementation, the printed circuit board further includes:

[0022] a through hole, the through hole passing through the first circuit board and the second circuit board;

[0023] The second conductive member is disposed in the through hole and connects the first circuit board and the second circuit board.

[0024] In a second aspect, an embodiment of the present application provides an electronic device, comprising a device body and any one of the printed circuit boards provided in the first aspect, arranged on the device body.

[0025] In a third aspect, an embodiment of the present application provides a method for manufacturing a printed circuit board, comprising:

[0026] Providing a second circuit board, the second circuit board including a first circuit layer, a first adhesive layer, a first dielectric layer, a second adhesive layer, and a second circuit layer that are stacked;

[0027] Processing a via hole that passes through the second circuit layer, the second bonding layer, the first dielectric layer, and the first bonding layer;

[0028] Plating metal in the via hole to form a first conductive member in the via hole, and connecting the first circuit layer and the second circuit layer with the first conductive member;

[0029] A plurality of first circuit boards are provided, and the first circuit boards and the second circuit boards are pressed together to connect the second circuit layer to the first circuit boards.

[0030] In a possible implementation, after providing the second circuit board, the method for manufacturing a printed circuit board further includes:

[0031] A detachable protective layer is provided on a side of the first circuit layer facing away from the first adhesive layer.

[0032] In a possible implementation, after providing a first circuit board and pressing the first circuit board and the second circuit board together to connect the second circuit layer to the first circuit board, the method further includes:

[0033] Remove the protective layer of the first circuit layer.

[0034] The printed circuit board, its manufacturing method, and electronic device provided in embodiments of the present application are characterized by providing vias that penetrate the second circuit layer, the second adhesive layer, the first dielectric layer, and the first adhesive layer, but not the first circuit layer, such that the bottom of the via is located precisely to one side of the first circuit layer. The first circuit layer is close to the external environment, and when laser ablation is used to remove residue from the bottom of the via, the heat generated by the laser ablation is directly transferred to the external environment through the first circuit layer, rather than being transferred between the first and second circuit layers, thereby preventing separation of the first and second circuit layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0036] Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0037] Figure 2 A schematic diagram of the structure of a printed circuit board provided by the related technology of this application;

[0038] Figure 3 for Figure 1 A schematic diagram of a process for manufacturing a printed circuit board;

[0039] Figure 4 For the production Figure 1 The printed circuit board shown is a schematic structural diagram of a second circuit board provided;

[0040] Figure 5 For Figure 4 Schematic diagram of machining vias on a structure;

[0041] Figure 6 For Figure 5 Schematic diagram of electroplating metal on vias shown;

[0042] Figure 7 For the production Figure 1 When the printed circuit board is shown, a plurality of first circuit boards are provided, and the first circuit boards and Figure 6 A schematic diagram of a circuit fabricated on a second circuit board shown;

[0043] Figure 8 For pressing Figure 7 Schematic diagram of the first circuit board and the second circuit board shown;

[0044] Figure 9 For demolition Figure 8 A schematic diagram of a protective layer on the first circuit layer shown;

[0045] Figure 10 For Figure 9 Schematic diagram of making through holes on the first circuit board and the second circuit board shown;

[0046] Figure 11 For Figure 10 Schematic diagram of electroplating metal in through-hole shown;

[0047] Figure 12 For Figure 11 A schematic diagram of circuit fabrication on the first circuit layer is shown;

[0048] Figure 13 For Figure 11 The diagram shows the intermediate process of making circuits on the first circuit layer.

[0049] Description of reference numerals:

[0050] 1-Printed circuit board; 2-Device body;

[0051] 10-first core board; 20-second core board; 21-first copper foil layer; 22-first connection layer; 23-base board; 24-second connection layer; 25-second copper foil layer; 26-connection hole; 27-copper foil piece;

[0052] 100-first circuit board; 110-second dielectric layer; 120-third circuit layer;

[0053] 200- third bonding layer;

[0054] 300 - second circuit board; 310 - first circuit layer; 320 - first bonding layer; 330 - first dielectric layer; 340 - second bonding layer; 350 - second circuit layer; 360 - protective layer;

[0055] 400-via;

[0056] 500-first conductive member;

[0057] 600-through hole;

[0058] 700- second conductive member;

[0059] 800-Fourth bonding layer.

[0060] To facilitate understanding of the solutions of the embodiments of the present application, the spline curves and arrows used in the numbers in the accompanying drawings are explained here: the components indicated by the spline curves without arrows can be solid components, that is, components with solid structures; the components indicated by the spline curves with arrows can be virtual components, that is, components without solid structures; in some cases, the components indicated by the spline curves with arrows can also be assemblies with solid structures or virtual structures.

[0061] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0063] It should be noted that, in this article, relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In the description of the embodiments of the present application, it should be understood that the orientation or positional relationship (if any) indicated by the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" etc. is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a restriction on the embodiments of the present application. Moreover, the term "comprise", "include" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not clearly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the phrase "comprising..." do not preclude the presence of other identical elements in the process, method, article, or device that includes the elements. If there is no conflict, the embodiments of the present application and the various features therein may be combined with each other and are all within the scope of protection of this application.

[0064] An embodiment of the present application provides an electronic device, Figure 1 A schematic diagram of the structure of an electronic device.

[0065] Specifically, see Figure 1 The electronic device includes a device body 2 and a printed circuit board 1 arranged on the device body 2.

[0066] The device body 2 provides physical support and protection for the printed circuit board 1. For example, the printed circuit board 1 can be installed inside the device body 2 using screws, slots, or other fixing methods. This not only ensures the stability of the printed circuit board 1, but also prevents the external environment (such as dust, moisture, etc.) from affecting the printed circuit board 1.

[0067] The printed circuit board (PCB) 1 is the core carrier for the functions of electronic devices. It carries the various components and circuits required for the device to implement key functions such as signal processing, data transmission, and power management. The device body 2 provides interfaces and user interfaces for external interaction with these functions, such as buttons, displays, and connectors.

[0068] In some embodiments, the printed circuit board 1 is a high-density interconnected printed circuit board, which uses small vias to form a high-density interconnection structure, and can achieve more circuit connections and functional integration in a limited space, so as to achieve miniaturization, lightweight and high performance of electronic equipment.

[0069] In other embodiments, printed circuit board 1 is a millimeter-wave radar circuit board. This is a core component of millimeter-wave radar equipment, responsible for transmitting and receiving high-frequency electromagnetic waves and processing reflected signals to obtain target information. Millimeter-wave radar circuit boards can be used in automotive, security and surveillance, drones, and robotics.

[0070] In some embodiments, the electronic device further includes a heat dissipation assembly (not shown in the figure), which is disposed on the device body 2 and located on one side of the printed circuit board 1. The heat dissipation assembly is used to dissipate heat from the printed circuit board 1 to ensure that the printed circuit board 1 and / or components connected to the printed circuit board 1 operate within a normal operating temperature range.

[0071] It should be noted that the embodiments of this application do not limit the specific type of electronic device and can be selected and used according to specific needs. For example, the electronic device includes radar equipment, satellite communication equipment, servers, smartphones, tablet computers, laptops, wearable devices, digital cameras, gaming devices, medical equipment, and industrial equipment.

[0072] It is understandable that Figure 1 Some components of the electronic device are only schematically shown, and the actual shapes, sizes, positions and structures of these components are not affected by the actual shapes, sizes, positions and structures of the electronic device. Figure 1 electronic devices may also include Figure 1 More or fewer parts.

[0073] The related art provides a printed circuit board, Figure 2 Schematic diagram of the structure of a printed circuit board.

[0074] See also Figure 2 The printed circuit board includes: a first core board 10; a second core board 20, the second core board 20 includes a first copper foil layer 21, a first connecting layer 22, a substrate 23, a second connecting layer 24 and a second copper foil layer 25 stacked in sequence, and the second copper foil layer 25 is arranged on the first core board 10; the second core board 20 also includes a connecting hole 26 and a copper foil part 27, the connecting hole 26 passes through the second connecting layer 24, the substrate 23, the first connecting layer 22 and the first copper foil layer 21, the copper foil part 27 is arranged in the connecting hole 26, and the copper foil part 27 connects the first copper foil layer 21 and the second copper foil layer 25.

[0075] When the connection hole 26 is formed, part of the first connection layer 22 and part of the second connection layer 24 remain at the bottom of the connection hole 26 and need to be removed by laser ablation.

[0076] However, the heat generated by laser ablation is transferred between the first core board 10 and the second copper foil layer 25 through the second copper foil layer 25 , which may easily cause the first core board 10 and the second copper foil layer 25 to separate, thereby causing the printed circuit board to fail.

[0077] In order to solve the above technical problems, the present invention provides a printed circuit board. Figure 4 For the production Figure 1 The printed circuit board 1 shown is a schematic structural diagram of a second circuit board 300 provided; Figure 5 For Figure 4 Schematic diagram of processing a via hole 400 on a structure; Figure 6 For Figure 5 Schematic diagram of electroplating metal on via 400 shown; Figure 7 For the production Figure 1 When the printed circuit board 1 is shown, a plurality of first circuit boards 100 are provided, and the first circuit boards 100 and Figure 6 A schematic diagram of circuits fabricated on a second circuit board 300 is shown; Figure 8 For pressing Figure 7 Schematic diagram of the first circuit board 100 and the second circuit board 300 shown; Figure 9 For demolition Figure 8 A schematic diagram of a protective layer 360 on the first circuit layer 310 is shown; Figure 10 For Figure 9 Schematic diagram of making through holes 600 on the first circuit board 100 and the second circuit board 300 shown; Figure 11 For Figure 10 Schematic diagram of electroplating metal in through hole 600 shown; Figure 12 For Figure 11 A schematic diagram of circuits fabricated on the first circuit layer 310 is shown; Figure 13 For Figure 11 The diagram shows the intermediate process of making circuits on the first circuit layer.

[0078] Specifically, see Figures 4 to 8The printed circuit board 1 includes a first circuit board 100 and a second circuit board 300. The second circuit board 300 includes: a first circuit layer 310, a first adhesive layer 320, a first dielectric layer 330, a second adhesive layer 340, and a second circuit layer 350 arranged in a stacked manner, and the second circuit layer 350 is connected to the first circuit board 100; a via 400, and the via 400 passes through the second circuit layer 350, the second adhesive layer 340, the first dielectric layer 330 and the first adhesive layer 320; a first conductive member 500, and the first conductive member 500 is arranged in the via 400, and the first conductive member 500 connects the first circuit layer 310 and the second circuit layer 350.

[0079] In this embodiment, printed circuit board 1 arranges vias 400 to penetrate second circuit layer 350, second adhesive layer 340, first dielectric layer 330, and first adhesive layer 320, but not through first circuit layer 310, such that the bottom of vias 400 is located precisely to one side of first circuit layer 310. First circuit layer 310 is close to the external environment. When laser ablation is used to remove residue from the bottom of the vias, the heat generated by the laser ablation is directly transferred to the external environment through first circuit layer 350, rather than between first circuit board 100 and second circuit layer 350. Consequently, separation of first circuit board 100 and second circuit layer 350 is prevented, and printed circuit board 1 does not fail.

[0080] By setting the first conductive member 500 in the via 400, the first conductive member 500 connects the first circuit layer 310 and the second circuit layer 350, so that the signal connection between the first circuit layer 310 and the second circuit layer 350 can be achieved, thereby achieving a more complex circuit connection, laying the foundation for the miniaturization and functional diversification of electronic devices.

[0081] It should be noted that the first adhesive layer 320 and the second adhesive layer 340 are relatively thin and are primarily used to bond the first circuit layer 310 and the second circuit layer 350 to the first dielectric layer 330. This embodiment does not limit the specific types of the first adhesive layer 320 and the second adhesive layer 340. For example, the first adhesive layer 320 and the second adhesive layer 340 may both be polyimide (PI) layers or prepreg (PP).

[0082] It should also be noted that both the first circuit layer 310 and the second circuit layer 350 may have multiple independent circuits. The first conductive member 500 connects the first circuit layer 310 and the second circuit layer 350, which may mean that the first conductive member 500 connects the independent circuits on the first circuit layer 310 and the independent circuits on the second circuit layer 350.

[0083] The preferred technical solution of the printed circuit board 1 of the embodiment of the present application is described below with reference to the accompanying drawings.

[0084] In some specific embodiments, the radial width of the through hole 400 gradually decreases from the hole opening to the hole bottom.

[0085] In this embodiment, the first conductive member 500 can be formed by electroplating metal on the hole wall of the via hole 400, and the radial width gradually decreases from the hole mouth to the hole bottom so that the plating liquid can flow more easily into the via hole 400. The first conductive member 500 can be formed by uniform electroplating, thereby improving the conductivity and mechanical strength of the first conductive member 500.

[0086] Moreover, the radial width of the via hole 400 gradually decreases from the hole mouth to the hole bottom, so that the hole wall of the via hole 400 is always facing the external environment. When using a laser to remove the residue in the via hole 400, the laser is more likely to contact the hole wall of the via hole 400, making the residue in the via hole 400 easier to remove.

[0087] In some other specific embodiments, the via hole 400 is a laser hole.

[0088] By using laser technology to process vias 400, precise aperture control can be achieved. This high precision translates into higher interconnect density, allowing more components to be accommodated on the same area of ​​PCB 1. For example, a carbon dioxide laser can be used to emit a beam into second circuit board 300 to form vias 400.

[0089] By using laser technology to process the via hole 400 , the via hole 400 can be processed quickly to improve production efficiency.

[0090] In some further specific embodiments, the first conductive member 500 is a copper foil member.

[0091] Copper has high electrical conductivity. By setting the first conductive member 500 as a copper foil member, the energy loss of the electrical signal during transmission can be reduced, thereby improving the transmission efficiency of the printed circuit board 1 and enhancing the electrical conductivity of the printed circuit board 1.

[0092] Through the precise etching process, complex circuit patterns can be formed on the copper foil, which helps to improve the manufacturing accuracy of the printed circuit board 1. This is especially important for high-density interconnected printed circuit boards 1, which can achieve a more sophisticated circuit layout of the printed circuit board 1.

[0093] In some other specific implementations, the first dielectric layer 330 is a polytetrafluoroethylene (PTFE) layer.

[0094] Printed circuit board 1 can be used in the field of millimeter-wave radar. By using a polytetrafluoroethylene layer as the first dielectric layer 330, the polytetrafluoroethylene layer has a relatively low dielectric constant and low dissipation factor. Electromagnetic waves experience minimal loss when propagating through the polytetrafluoroethylene layer, effectively transmitting millimeter-wave signals without significant signal attenuation or distortion, thereby ensuring the integrity of transmitted and received signals.

[0095] In some embodiments, see Figures 10 to 12 The printed circuit board 1 further includes a through hole 600 and a second conductive member 700 . The through hole 600 passes through the first circuit board 100 and the second circuit board 300 . The second conductive member 700 is disposed in the through hole 600 . The second conductive member 700 connects the first circuit board 100 and each second circuit board 300 .

[0096] In this embodiment, the circuit layer of the first circuit board 100 and the circuit layer of the second circuit board 300 both have circuits, and the through hole 600 passes through each circuit board, essentially passing through the preset circuits on each circuit board. When the second conductive member 700 is set in the through hole 600, the second conductive member 700 can connect the preset circuits on each layer of the circuit board to each other. Thus, electrical signals can be transmitted between the layers of the circuit boards to meet the signal connection requirements of the printed circuit board 1.

[0097] Currently, after the via hole 400 is processed, metal may be electroplated in the via hole 400 to form the first conductive member 500 .

[0098] During the electroplating process of vias 400, the outer first circuit layer 310 is also electroplated, which can easily cause the first circuit layer 310 to be too thick (for example, 50μm to 55μm). This makes it difficult to form antenna circuits on the first circuit layer 310. Therefore, it is necessary to thin the first circuit layer 310 before forming the circuits.

[0099] However, the first circuit layer 310 undergoes a thickening and thinning process, which results in a large thickness difference of the first circuit layer 310, resulting in low pattern accuracy of the antenna line and a large Elbow Avoidance (EA) value at the right angle of the pattern, thereby affecting the gain of the signal transmission and reception of the printed circuit board 1. Figure 13 As shown, at a right angle to the pattern, the shortest distance from the corner vertex O when etching the circuit to the arc path A when etching the circuit is EA.

[0100] Moreover, when the printed circuit board 1 has a through hole that passes through the first circuit board 100 and the second circuit board 300, it is usually necessary to cover the opening of the through hole during the thinning process of the first circuit board 100, which will cause a hole ring to appear at the opening, and the hole ring needs to be ground with a sanding belt.

[0101] However, the material of the first dielectric layer 330 is usually relatively soft. When using a sanding belt to grind the hole ring, external force acts on the first dielectric layer 330, causing the first dielectric layer 330 to sag, thereby causing the hole mouth of the through hole to sag, and further causing the surface of the first circuit layer 310 to be uneven, affecting the gain of signal reception and transmission of the printed circuit board 1.

[0102] Therefore, in order to solve the above technical problems, in some embodiments, please refer to Figures 4 to 9 The second circuit board 300 further includes a protective layer 360 , which is detachably connected to a side of the first circuit layer 310 facing away from the first adhesive layer 320 .

[0103] In this embodiment, a protective layer 360 is provided and removably attached to the side of the first circuit layer 310 facing away from the first adhesive layer 320. During the electroplating of the via 400, the outer protective layer 360 is plated, while the first circuit layer 310 between the protective layer 360 and the first dielectric layer 330 is not plated. During the electroplating process of the via 400, the thickness of the first circuit layer 310 remains unchanged (e.g., 3 μm to 8 μm), and its surface remains relatively flat. After the electroplating is complete, the protective layer 360 only needs to be removed to fabricate the circuit on the first circuit layer 310, without requiring any thinning. The resulting antenna circuit has a high pattern accuracy, with an EA value of 5 μm to 10 μm at right angles, which does not affect the signal transmission and reception gain of the printed circuit board 1. Furthermore, the first circuit layer 310 does not require any thinning, and its surface remains flat, without affecting the signal transmission and reception gain of the printed circuit board 1.

[0104] In order to further understand the technical solution of this embodiment, a comparative example is given to illustrate the beneficial effects of this embodiment (the comparative example can refer to the relevant technology).

[0105] In the comparative example, the connection hole 26 penetrates the second connection layer 24, the substrate 23, the first connection layer 22, and the first copper foil layer 21. To avoid separation of the first core board 10 from the second copper foil layer 25 due to the increased laser radiation energy of a carbon dioxide laser, an ultraviolet cold light source was used instead to clean the bottom of the connection hole 26. However, this results in a long processing cycle and low processing efficiency for the printed circuit board.

[0106] The printed circuit board 1 according to the embodiment of the present application, without requiring a change in the cleaning device (still using the carbon dioxide laser used to process the via 400), can still clean the bottom of the via 400 without causing separation between the first circuit board 100 and the second circuit layer 350. Compared to the printed circuit board of the comparative example, the printed circuit board 1 provided by the embodiment of the present application has a shorter processing cycle and higher processing efficiency.

[0107] In some specific embodiments, the protection layer 360 is bonded to the first circuit layer 310 by adhesive.

[0108] In a specific implementation, glue with moderate adhesion can be selected. When there is no external force acting on the protective layer 360, the protective layer 360 can be firmly adhered to the first circuit layer 310; when there is an external force acting on the protective layer 360, the protective layer 360 can be removed.

[0109] In some other specific embodiments, the protective layer 360 is a copper foil layer.

[0110] The copper foil has a certain hardness. In this embodiment, the copper foil layer is used as the protective layer 360, which is convenient for removing the copper foil.

[0111] The surface of the copper foil is relatively smooth. In this embodiment, by using the copper foil layer as the protective layer 360 , wrinkles on the surface of the first circuit layer 310 can be prevented.

[0112] The material cost of copper foil is relatively low. In this embodiment, by using the copper foil layer as the protective layer 360 , the manufacturing cost of the printed circuit board 1 can be reduced.

[0113] In some embodiments, see Figure 8 The printed circuit board 1 further includes a plurality of fourth adhesive layers 800 ; the number of the first circuit boards 100 is multiple, and two adjacent first circuit boards 100 are connected via the fourth adhesive layer 800 .

[0114] By providing multiple first circuit boards 100 , two adjacent first circuit boards 100 are connected via the fourth adhesive layer 800 to meet the high-density wiring requirements of the printed circuit board 1 , so that the printed circuit board 1 can connect more components within a limited space.

[0115] In other embodiments, see Figure 7 and Figure 8 The printed circuit board 1 also includes a third adhesive layer 200. The first circuit board 100 includes a second dielectric layer 110 and two third circuit layers 120 respectively arranged on both sides of the second dielectric layer 110. The second circuit layer 350 is connected to the third circuit layer 120 located on the outer layer through the third adhesive layer 200.

[0116] By selecting a suitable dielectric material with a suitable thickness as the second dielectric layer 110 , the signal transmission characteristics between various circuit layers can be optimized, for example, crosstalk and reflection can be reduced, which helps to improve the integrity and speed of signal transmission.

[0117] Furthermore, by disposing the second dielectric layer 110 between the two third circuit layers 120 , the overall thickness of the first circuit board 100 is increased, thereby improving the mechanical properties of the first circuit board 100 , such as bending resistance and torsional resistance.

[0118] Furthermore, the second dielectric layer 110 is an epoxy glass cloth laminate, which has a flame retardant 4 (FR4) effect.

[0119] In this embodiment, the second dielectric layer 110 is configured as an epoxy glass cloth laminate, which can provide good mechanical properties for the first circuit layer 310 and the second circuit layer 350 , thereby improving the structural stability of the second circuit board 300 .

[0120] Furthermore, the epoxy glass cloth laminate has good flame retardancy and can improve the safety of the printed circuit board 1 .

[0121] It should be noted that this embodiment does not limit the specific types of the third adhesive layer 200 and the fourth adhesive layer 800, and can be adjusted according to specific needs. For example, the third adhesive layer 200 and the fourth adhesive layer 800 can both be prepreg (PP).

[0122] See also Figures 3 to 8 The present invention also provides a method for manufacturing a printed circuit board, comprising:

[0123] S100 , providing a second circuit board 300 , wherein the second circuit board 300 includes a first circuit layer 310 , a first adhesive layer 320 , a first dielectric layer 330 , a second adhesive layer 340 , and a second circuit layer 350 , which are stacked.

[0124] S200 , processing a via hole 400 penetrating the second circuit layer 350 , the second adhesive layer 340 , the first dielectric layer 330 , and the first adhesive layer 320 .

[0125] In a specific implementation, the via hole 400 may be made on the second circuit board 300 by laser processing.

[0126] S300 , plating metal in the via hole 400 to form a first conductive member 500 in the via hole 400 , and connecting the first circuit layer 310 and the second circuit layer 350 .

[0127] In a specific implementation, an electroplating device may be used to electroplate metal (eg, copper) onto the hole wall of the via hole 400 .

[0128] S400 , providing a first circuit board 100 , and pressing the first circuit board 100 and the second circuit board 300 together to connect the second circuit layer 350 to the first circuit board 100 .

[0129] Specifically, the method for manufacturing the printed circuit board 1 of this embodiment adopts all the technical solutions of any of the aforementioned printed circuit boards 1, and therefore has at least all the beneficial effects brought about by the technical solutions of the aforementioned embodiments, which will not be described in detail here.

[0130] The following describes a preferred technical solution for the method of manufacturing the printed circuit board 1 according to an embodiment of the present application with reference to the accompanying drawings.

[0131] In some embodiments, as described in the above embodiments, in order to avoid the first circuit layer 310 being plated with metal while the via hole 400 is being plated with metal, please continue to refer to Figures 3 to 8 After step S100, the method for manufacturing the printed circuit board 1 further includes:

[0132] S110 , disposing a detachable protective layer 360 on a side of the first circuit layer 310 facing away from the first adhesive layer 320 .

[0133] S120 , disposing a detachable protective layer 360 on a side of the second circuit layer 350 facing away from the second adhesive layer 340 .

[0134] S130 , removing the protective layer 360 on the second circuit layer 350 .

[0135] In this embodiment, by providing two protective layers 360 , the other layers of the first circuit board 100 are sandwiched between the two protective layers 360 . The two protective layers 360 can protect the other layers and prevent the external environment from corroding the other layers between the two protective layers 360 .

[0136] By providing the protection layer 360 on the first circuit layer 310 , the thickness of the first circuit layer 310 does not change during the electroplating process of the via hole 400 , and the surface is relatively flat, which facilitates the subsequent production of circuits with higher precision.

[0137] Moreover, when a protective layer 360 is provided on the first circuit layer 310, laser ablation is used to remove the residue at the bottom of the via hole 400. The heat generated by the laser ablation can be directly transferred to the external environment through the first circuit layer 310 and the protective layer 360, which facilitates heat dissipation and does not cause the first circuit board 100 to separate from the second circuit layer 350.

[0138] It should be noted that the protective layer 360 on the first circuit layer 310 and the protective layer 360 on the second circuit layer 350 can be provided at the same time or separately, and this application does not limit this.

[0139] In other embodiments, see Figure 7 After step S300, the method for manufacturing the printed circuit board 1 further includes:

[0140] S310 , fabricating circuits on the second circuit board 300 and the first circuit board 100 .

[0141] In specific implementation, after designing the circuit diagram, the circuit layers (for example, the first circuit layer 310 and the second circuit layer 350 on the second circuit board 300, and the third circuit layer 120 on the first circuit board 100) can be etched using an etching machine according to the circuit diagram to form circuits of specific shapes on each circuit layer, thereby meeting wiring requirements.

[0142] In some embodiments, please refer to Figure 7 and Figure 8 , step S400 includes:

[0143] S410 , placing the second circuit board 300 on one side of the first circuit board 100 , and placing an adhesive sheet between the first circuit board 100 and the second circuit board 300 .

[0144] S420 , under a preset temperature and a preset pressure, pressing the second circuit board 300 and the first circuit board 100 together, so that the bonding sheet between the first circuit board 100 and the second circuit board 300 forms a third bonding layer 200 .

[0145] In a specific implementation, a laminator can be used to press the first circuit board 100 and the second circuit board 300 together, so that the connection between the second circuit board 300 and the first circuit board 100 is relatively firm.

[0146] In some embodiments, see Figure 9 After step S400, the method for manufacturing the printed circuit board 1 further includes:

[0147] S500 , removing the protection layer 360 on the first circuit layer 310 .

[0148] After the via 400 is electroplated, it is only necessary to remove the protective layer 360 to fabricate the circuit on the first circuit layer 310 without thinning. The antenna circuit fabricated has a high graphic accuracy and will not affect the gain of the signal reception and transmission of the printed circuit board 1.

[0149] In some embodiments, please refer to Figures 10 to 12 After step S600, the method for manufacturing the printed circuit board 1 further includes:

[0150] S700 , making through holes 600 on the first circuit board 100 and the second circuit board 300 , wherein the through holes 600 penetrate the first circuit board 100 and the second circuit board 300 .

[0151] In a specific implementation, the through holes 600 may be made on the first circuit board 100 and the second circuit board 300 by mechanical drilling.

[0152] S800 , electroplating metal on the through hole 600 to form a second conductive member 700 in the through hole 600 , and connecting the second circuit board 300 and the first circuit board 100 through the second conductive member 700 .

[0153] In a specific implementation, an electroplating device may be used to electroplate metal (eg, copper) onto the hole wall of the through hole 600 .

[0154] In some other embodiments, after step S800, the method for manufacturing the printed circuit board 1 further includes:

[0155] S900 , fabricating circuits on the first circuit layer 310 .

[0156] In this embodiment, after electroplating on the first circuit layer 310, the overall thickness of the first circuit layer 310 can be 25μm to 30μm, which meets the thickness requirements for pattern production and eliminates the need for thinning, allowing for direct outer layer patterning. By eliminating the need for metal plating and subsequent thinning, the surface uniformity of the formed first circuit layer 310 is significantly improved, and the EA value in the antenna area can be controlled.

[0157] In some other embodiments, the method for manufacturing the printed circuit board 1 may further include processes such as soldering, surface treatment, peripheral molding, and electrical testing. The above processes are known in the art and will not be described in detail here.

[0158] It should be understood that the embodiments of the present application are not limited to the precise structures described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A printed circuit board, characterized in that: The invention comprises a first circuit board (100) and a second circuit board (300), wherein the second circuit board (300) comprises: A first circuit layer (310), a first adhesive layer (320), a first dielectric layer (330), a second adhesive layer (340), and a second circuit layer (350) are stacked, and the second circuit layer (350) is connected to the first circuit board (100); A via hole (400), wherein the via hole (400) penetrates the second circuit layer (350), the second bonding layer (340), the first dielectric layer (330) and the first bonding layer (320); A first conductive member (500), wherein the first conductive member (500) is disposed in the via hole (400), and the first conductive member (500) connects the first circuit layer (310) and the second circuit layer (350).

2. The printed circuit board according to claim 1, characterized in that: The radial width of the through hole (400) gradually decreases from the hole opening to the hole bottom.

3. The printed circuit board according to claim 1, characterized in that: The via hole (400) is a laser hole; The first conductive member (500) is a copper foil member; The first dielectric layer (330) is a polytetrafluoroethylene layer.

4. The printed circuit board according to any one of claims 1 to 3, characterized in that: The second circuit board (300) further comprises a protective layer (360), wherein the protective layer (360) is detachably connected to a side of the first circuit layer (310) facing away from the first adhesive layer (320); The protective layer (360) is a copper foil layer.

5. The printed circuit board according to any one of claims 1 to 3, characterized in that: Also includes a third adhesive layer (200) and a plurality of fourth adhesive layers (800); There are a plurality of first circuit boards (100), and two adjacent first circuit boards (100) are connected via the fourth adhesive layer (800); The first circuit board (100) comprises a second dielectric layer (110) and two third circuit layers (120) respectively arranged on both sides of the second dielectric layer (110); the second circuit layer (350) is connected to the third circuit layer (120) located on the outer layer via the third adhesive layer (200).

6. The printed circuit board according to any one of claims 1 to 3, characterized in that: Also includes: A through hole (600), the through hole (600) passing through the first circuit board (100) and the second circuit board (300); A second conductive member (700), wherein the second conductive member (700) is disposed in the through hole (600), and the second conductive member (700) connects the first circuit board (100) and the second circuit board (300).

7. An electronic device, characterized in that: The invention comprises a device body (2) and a printed circuit board (1) as claimed in any one of claims 1 to 6 arranged on the device body (2).

8. A method for manufacturing a printed circuit board according to any one of claims 1 to 6, characterized in that: include: Providing a second circuit board (300), the second circuit board (300) comprising a first circuit layer (310), a first adhesive layer (320), a first dielectric layer (330), a second adhesive layer (340) and a second circuit layer (350) which are stacked; Processing a via hole (400) that penetrates the second circuit layer (350), the second bonding layer (340), the first dielectric layer (330) and the first bonding layer (320); Plating metal in the via hole (400) to form a first conductive member (500) in the via hole (400), and connecting the first circuit layer (310) and the second circuit layer (350); A first circuit board (100) is provided, and the first circuit board (100) and the second circuit board (350) are pressed together so that the second circuit layer (350) is connected to the first circuit board (100).

9. The method for manufacturing a printed circuit board according to claim 8, characterized in that: After providing the second circuit board (300), the method further includes: A detachable protective layer (360) is provided on a side of the first circuit layer (310) facing away from the first adhesive layer (320).

10. The method for manufacturing a printed circuit board according to claim 9, characterized in that: After providing the first circuit board (100), and pressing the first circuit board (100) and the second circuit board (300) together so that the second circuit layer (350) is connected to the first circuit board (100), the method further comprises: The protective layer (360) of the first circuit layer (310) is removed.

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