High frequency board and high frequency board manufacturing method

Abstract

The present application is applicable to the technical field of circuit boards, and proposes a high-frequency board, which includes N metal layers arranged in sequence along a first direction, where N is an integer greater than 2; the first metal layer of the high-frequency board is arranged on the outer surface of the high-frequency board, and a window portion is provided in the first metal layer; the second metal layer of the high-frequency board is arranged on the first high-frequency core board, and a signal line is provided in the second metal layer, and the orthographic projection of the signal line on the first metal layer is located in the window portion; the high-frequency board is provided with a metallized hole, and the metallized hole connects the first metal layer and the signal line. The present application also proposes a method for manufacturing a high-frequency board. The above-mentioned high-frequency board and high-frequency board manufacturing method solve the abnormal problems such as copper surface pits and line defects caused by the soft high-frequency core board, thereby improving product quality and product reliability.

Description

Technical Field

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

[0002] A high-frequency board is a specialized circuit board with a relatively high electromagnetic frequency, capable of transmitting signals at high frequencies, high speeds, and over long distances. Limited by the market price of high-frequency materials, existing high-frequency boards mostly utilize a mixed-pressure stacking structure. This means that, in addition to the necessary signal layer, which uses high-frequency board materials to meet requirements for signal transmission speed, signal integrity, and impedance matching, the remaining layers still utilize conventional glass fiber epoxy resin board materials. To prevent interference between signal lines, the high-frequency layer is generally located on the outermost layer, but this design necessitates the protection of the signal layer during manufacturing. High-frequency core boards made of polytetrafluoroethylene (PTFE) are relatively soft, and impurities adhering during the manufacturing process can easily cause anomalies such as copper surface pits and line defects, impacting product quality. Summary of the Invention

[0003] In view of this, the present application provides a high-frequency board and a high-frequency board manufacturing method to solve the abnormal problems of existing high-frequency boards such as copper surface pits and line defects caused by the soft high-frequency core board.

[0004] The first aspect of the present application provides a high-frequency board, which includes N metal layers arranged in sequence along a first direction, where N is an integer greater than 2; the first metal layer of the high-frequency board is arranged on the outer surface of the high-frequency board, and a window portion is provided in the first metal layer; the second metal layer of the high-frequency board is arranged on a first high-frequency core board, and a signal line is provided in the second metal layer, and the orthographic projection of the signal line on the first metal layer is located in the window portion; a metallized hole is provided in the high-frequency board, and the metallized hole conducts electricity between the first metal layer and the signal line.

[0005] In one embodiment, the high-frequency board is further provided with a metallized shielding hole, which is provided around the signal line and passes through the first metal layer, the second metal layer and extends at least to the third metal layer.

[0006] In one embodiment, the first metal layer is made of a first copper foil, a first insulating dielectric layer is provided between the first metal layer and the first high-frequency core board, and the high-frequency board further includes at least one second insulating dielectric layer and at least one sub-board stacked on the side of the first high-frequency core board facing away from the first metal layer, wherein the first insulating dielectric layer is made of high-frequency material.

[0007] In one embodiment, the high-frequency board further includes a second copper foil, and the second copper foil is disposed on a side of the sub-board facing away from the first copper foil.

[0008] In one embodiment, the first high-frequency core board is a double-sided high-frequency core board or a single-sided high-frequency core board, and the material of the core board layer of the first high-frequency core board is at least one of polytetrafluoroethylene, hydrocarbon resin, and polyphenylene ether resin; the sub-board adopts a high-frequency core board or a non-high-frequency core board, and the material of the core board layer of the non-high-frequency core board is epoxy resin.

[0009] In one embodiment, a chip mounting area is provided in the first metal layer.

[0010] The second aspect of the present application provides a method for manufacturing a high-frequency board, for manufacturing the high-frequency board provided in the first aspect, wherein the method comprises:

[0011] A multilayer board is provided, comprising N metal layers sequentially spaced apart along a first direction, where N is an integer greater than 2, wherein a first metal layer of the multilayer board is disposed on a surface of the multilayer board, a second metal layer is disposed on a first high-frequency core board, and a signal line is disposed in the second metal layer;

[0012] Making metallized holes in the first metal layer and the second metal layer, wherein the metallized holes conduct electricity between the first metal layer and the signal line;

[0013] A window portion is formed on the first metal layer, and the orthographic projection of the signal line on the first metal layer is located within the window portion.

[0014] In one embodiment, providing a multilayer board includes:

[0015] Providing a first copper foil, a first prepreg, the first high-frequency core board, at least one second prepreg and at least one daughter board;

[0016] Fabricate inner layer circuits on the first high-frequency core board and at least one of the daughter boards;

[0017] The first copper foil, the first prepreg, the first high-frequency core board, at least one second prepreg and at least one sub-board are stacked and pressed in sequence.

[0018] In one embodiment, the high-frequency board manufacturing method further includes:

[0019] Using target patterns provided in the second and third metal layers as drilling references, a shielding hole is drilled from one side of the first metal layer in the multilayer board; or, a first shielding sub-hole is provided in the second and third metal layers of the multilayer board, and a second shielding sub-hole is drilled from the first metal layer toward the second metal layer, the second shielding sub-hole being connected to the first shielding hole to form a shielding hole;

[0020] The shielding hole is made into a metallized shielding hole.

[0021] In one embodiment, before laminating and pressing the boards, the high-frequency board manufacturing method further includes:

[0022] The first high-frequency core board and the board edge area of the sub-board are provided with a fusion zone, and the second prepreg sandwiched between the fusion zones is fused;

[0023] making a fixing hole in the fusion zone;

[0024] The fixing holes are penetrated by rivets.

[0025] The high-frequency board and high-frequency board manufacturing method provided in this application set a signal line on the first high-frequency core board, which can meet the requirements of signal transmission speed, signal integrity and impedance matching; the first high-frequency core board is built-in to avoid abnormal problems such as copper surface pits and line defects during processing due to its soft material; and because the signal line is built-in, the high-frequency board can protect the signal line, ensuring that the signal line is not easily affected by the external environment when subsequent electronic products are used, thereby improving product reliability. The above-mentioned high-frequency board reduces the manufacturing difficulty and improves product quality and product reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1 This is a structural diagram of a high-frequency board in one embodiment of the present application;

[0028] Figure 2 This is a schematic structural diagram of the first metal layer and the second metal layer of the high-frequency board in one embodiment of the present application;

[0029] Figure 3 This is a flow chart of a method for manufacturing a high-frequency board in one embodiment of the present application;

[0030] Figure 4 A flow chart of a multilayer board is provided in one embodiment of the present application.

[0031] The meanings of the marks in the figure are:

[0032] 100, high-frequency board; L1, first metal layer; L2, second metal layer; L3, third metal layer; L4, fourth metal layer; L5, fifth metal layer; L6, sixth metal layer; L7, seventh metal layer; L8, eighth metal layer; 10, first high-frequency core board; 20, first copper foil; 30, daughter board; 40, first insulating dielectric layer; 50, second insulating dielectric layer; 60, second copper foil; 101, window portion; 102, metallized hole; 103, signal line area. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the following further describes this application in detail with reference to the accompanying drawings, i.e., embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0034] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it may be directly or indirectly on the other component. When a component is referred to as being "connected to" another component, it may be directly or indirectly connected to the other component. The terms "first" and "second" are used only for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly specifying the number of technical features. "Multiple" means two or more, unless otherwise expressly specified.

[0035] It should also be noted that, in the embodiments of the present application, the same figure mark represents the same component or the same part. For the same parts in the embodiments of the present application, the figure may only mark one of the parts or components as an example. It should be understood that the figure mark also applies to other identical parts or components.

[0036] In order to illustrate the technical solution of the present application, the following description is given with reference to specific drawings and embodiments.

[0037] The embodiment of the first aspect of the present application proposes a high frequency board. Figure 1 and Figure 2 The high frequency board 100 includes N metal layers sequentially spaced apart along a first direction, where N is an integer greater than 2. The first direction is the stacking direction of the high frequency board 100, i.e., the thickness direction of the high frequency board 100. Figure 1 For example, the high-frequency board 100 includes a first metal layer L1 to an eighth metal layer L8 , which are 8 metal layers in total, but is not limited thereto. For example, N may also be equal to 3, 4, 6, 10, etc.

[0038] The first metal layer L1 is disposed on the outer surface of the high-frequency board 100 and is the outermost layer of the high-frequency board 100. The second metal layer L2 is the second outermost metal layer of the high-frequency board 100. The second metal layer L2 of the high-frequency board 100 is disposed on the first high-frequency core board 10 and has signal lines disposed therein.

[0039] A window portion 101 is provided in the first metal layer L1; the signal line is located in the signal line area 103, and the orthographic projection of the signal line on the first metal layer L1 is located in the window portion 101, that is, the first metal layer L1 is not provided with copper foil in the area corresponding to the signal line to avoid affecting the signal transmission of the signal line.

[0040] The high-frequency board 100 is provided with metallized holes 102, which conduct electricity between the first metal layer L1 and the signal line. Since the signal line needs to transmit signals, the present application integrates the signal line, and the metallized holes 102 can conduct electricity between the first metal layer L1 located on the outermost layer and the signal line, thereby transmitting the signal line signal to the outermost layer.

[0041] The high-frequency board 100 provided in this application sets a signal line on the first high-frequency core board 10, which can meet the requirements of signal transmission speed, signal integrity, and impedance matching. The first high-frequency core board 10 is built-in to avoid abnormal problems such as copper surface pits and line defects caused by its soft material during processing. In addition, since the signal line is built-in, the high-frequency board 100 can protect the signal line, ensuring that the signal line is not easily affected by the external environment when subsequent electronic products are used, thereby improving product reliability. The above-mentioned high-frequency board 100 reduces the manufacturing difficulty and improves product quality and product reliability.

[0042] Optionally, there may be one or more window portions 101 in the first metal layer L1 , and each window portion 101 may correspond to one or more signal lines.

[0043] In one embodiment, the high-frequency board 100 is further provided with a metallized shielding hole (not shown). The metallized shielding hole is provided around the signal line and penetrates the first metal layer L1 and the second metal layer and extends to at least the third metal layer.

[0044] The number of signal lines can be multiple, and the number of metallized shielding holes can also be multiple, wherein the metallized shielding holes can be arranged around multiple signal lines; the metallized shielding holes pass through the first metal layer L1, the second metal layer and extend at least to the third metal layer, which can shield the influence of other signals on the signal lines in the first direction.

[0045] In one embodiment, the first metal layer L1 is made of a first copper foil, and a first insulating dielectric layer 40 is disposed between the first metal layer L1 and the first high-frequency core board 10. In other embodiments, the first metal layer L1 may also be a metal layer on the core board. The first insulating dielectric layer 40 is made of a high-frequency material. The high-frequency board 100 also includes at least one second insulating dielectric layer 50 and at least one daughter board 30, stacked on the side of the first high-frequency core board 10 facing away from the first metal layer L1.

[0046] In this embodiment, the high frequency board 100 is a mixed pressure stacked structure. Figure 1 For example, the number of the daughter boards 30 is three, but the present invention is not limited thereto.

[0047] Furthermore, the high frequency board 100 further includes a second copper foil 60, which is disposed on a side of the sub-board 30 that is away from the first copper foil. Figure 1 For example, a high-frequency board 100 includes, in sequence, a first copper foil, a first insulating dielectric layer 40, a first high-frequency core board 10 (including L2 and L3), a second insulating dielectric layer 50, a daughter board 30 (including L4 and L5), a second insulating dielectric layer 50, a daughter board 30 (including L6 and L7), and a second copper foil 60. Both the first high-frequency core board 10 and the daughter board 30 are double-sided boards. It is understood that the first high-frequency core board 10 and / or the daughter board 30 may also be single-sided boards, and this is not limited in this application. The second copper foil 60 may be omitted.

[0048] Optionally, the first high-frequency core board 10 is a double-sided high-frequency core board or a single-sided high-frequency core board, and the material of the core board layer of the first high-frequency core board 10 is at least one of polytetrafluoroethylene, hydrocarbon resin, and polyphenylene ether resin.

[0049] Optionally, the sub-board 30 adopts a high-frequency core board or a non-high-frequency core board, and the material of the core board layer of the non-high-frequency core board is epoxy resin or other materials used for common core boards.

[0050] In one embodiment, a chip attach area (BGA) is provided in the first metal layer L1 , and the signal line is electrically connected to the chip attach area through the metallized hole 102 .

[0051] The second aspect of the present application provides a method for manufacturing a high-frequency board, which is used to manufacture the high-frequency board 100 of the first aspect. Figures 1 to 3 , the production of high frequency board 100 includes:

[0052] Step S10: providing a multilayer board, wherein the multilayer board comprises N metal layers sequentially spaced apart along a first direction.

[0053] Wherein, N is an integer greater than 2. The multilayer board is a laminated structure formed by laminating multiple core boards, and the multilayer board includes at least one high-frequency core board, namely, a first high-frequency core board 10 .

[0054] The first metal layer L1 of the multilayer board is disposed on the surface of the multilayer board, and the second metal layer L2 is disposed on the first high-frequency core board 10 , and a signal line is disposed in the second metal layer L2 .

[0055] Step S20: making metallized holes 102 in the first metal layer L1 and the second metal layer L2.

[0056] Plated via 102 connects the first metal layer L1 to the signal line. Specifically, a blind via is drilled through the first metal layer L1 and the second metal layer L2 in the multilayer board. The blind via is then metallized to form plated via 102. The blind via is drilled from the first metal layer L1 to the second metal layer L2. A blind via target pattern is placed on the second metal layer L2 to ensure proper alignment between the blind via and the signal line. In other embodiments, plated via 102 may also be a through-hole.

[0057] The signal line is the main carrier for signal reception and transmission. It needs to transmit the received signal to the chip for processing and transmit the signal according to the chip's instructions. After the signal line is built into the present application, the first metal layer L1 located at the outermost layer and the signal line can be connected through the metallized hole 102 to achieve electrical conduction between the signal line and the chip mounting area, thereby achieving communication between the signal line and the chip.

[0058] Step S30: forming a window portion 101 on the first metal layer L1.

[0059] The orthographic projection of the signal line on the first metal layer L1 is located within the window portion 101, that is, the position of the window portion 101 corresponds to the signal line. There can be one or more window portions 101 in the first metal layer L1, and each window portion 101 can correspond to one or more signal lines.

[0060] Specifically, after step S20, step S30 is performed, which is to form outer layer circuits on the multilayer board, form circuit patterns in the first metal layer L1, and simultaneously form the window portion 101. It is understood that step S30 can also be placed before step S20.

[0061] The above-mentioned high-frequency board manufacturing method can produce a high-frequency board 100, in which the signal line is set on the first high-frequency core board 10, which can meet the requirements of signal transmission speed, signal integrity, and impedance matching. The first high-frequency core board 10 is built-in to avoid abnormal problems such as copper surface pits and line defects caused by its soft material during processing. In addition, since the signal line is built-in, the high-frequency board 100 can protect the signal line, ensuring that the signal line is not easily affected by the external environment when subsequent electronic products are used, thereby improving product reliability. The above-mentioned high-frequency board 100 reduces the manufacturing difficulty and improves product quality and product reliability.

[0062] Please refer to Figures 1 to 4 In one embodiment, step S10 of providing a multilayer board specifically includes:

[0063] Step S11 : providing a first copper foil, a first prepreg, a first high-frequency core board 10 , at least one second prepreg, and at least one daughter board 30 .

[0064] The first high-frequency core board 10 can be a double-sided high-frequency core board or a single-sided high-frequency core board, the daughter board 30 can also be a single-sided board or a double-sided board, and the daughter board 30 can be a high-frequency core board or an ordinary non-high-frequency core board; optionally, the first semi-cured sheet is a high-frequency material.

[0065] Optionally, a second copper foil 60 is further provided in step S11.

[0066] Step S12 : fabricating inner layer circuits on the first high-frequency core board 10 and at least one daughter board 30 .

[0067] by Figure 1 For example, according to conventional processes, the pattern circuits and board edge target patterns of layers L2-L7 are normally produced. The second metal layer L2 and the third metal layer L3 are two metal layers of the high-frequency core board, and the signal layer is formed in the second metal layer L2.

[0068] Step S13: stacking and pressing the first copper foil, the first prepreg, the first high-frequency core board 10, at least one second prepreg, and at least one daughter board 30 in sequence.

[0069] by Figure 1 For example, a multilayer board is produced by sequentially stacking and laminating a first copper foil, a first prepreg, a first high-frequency core board 10, a second prepreg, a daughter board 30, a second prepreg, a daughter board 30, and a second copper foil 60. After lamination, the first prepreg forms the first insulating dielectric layer 40, and the second prepreg forms the second insulating dielectric layer 50.

[0070] After step S10, the high-frequency board manufacturing method further includes the step of processing metallized shielding holes. The metallized shielding holes are provided around the signal lines to shield signal interference. The metallized shielding holes can be provided around the signal lines or around the signal line area.

[0071] Specifically, a shielding hole is first drilled; after the shielding hole is drilled, the shielding hole is made into a metallized shielding hole.

[0072] In one embodiment, the shielding via is a cross-layer blind via. The second metal layer L2 is not provided with a shielding via. Using target patterns provided in the second metal layer L2 and the third metal layer as drilling references, the shielding via is drilled in the multilayer board from one side of the first metal layer L1 toward the inner layer (the bottom layer of the via). The target patterns for the cross-layer blind via are provided on the sub-outer layer and the inner layer (the bottom layer of the via). For example, a target pattern is provided on one diagonal line of the inner layer and a target pattern is provided on the other diagonal line of the sub-outer layer. When drilling the outermost layer, the alignment system of the inner and sub-outer layers is used to ensure alignment of the cross-layer blind via with both the sub-outer layer and the inner layer.

[0073] In another embodiment, the shielding hole is formed in a stacking manner. A first shielding sub-hole is provided in the second metal layer L2 and the third metal layer of the multilayer board. After lamination, a second shielding sub-hole is drilled from the first metal layer L1 to the second metal layer L2. The second shielding sub-hole is connected to the first shielding sub-hole to form a shielding hole.

[0074] In one embodiment, before stacking and pressing, the manufacturing method further includes: providing fusion zones in the edge areas of the first high-frequency core board 10 and the sub-board 30, fusing the second semi-cured sheet sandwiched between the fusion zones; making fixing holes in the fusion zones; and using rivets to penetrate the fixing holes.

[0075] By adopting the above technical solution, the core board can be pre-fixed before lamination. This embodiment is suitable for pre-fixing the first high-frequency core board 10 and one or more sub-boards 30. After pre-fixing, the first prepreg, the second prepreg, the first copper foil 20, and the second copper foil 60 are stacked and then pressed.

[0076] Conventional pre-fixing includes riveting fixation or fusion fixation. Riveting requires punching / drilling the core board and the semi-cured sheet sandwiched between the core boards in advance to facilitate subsequent rivet perforation fixation. However, during riveting, the semi-cured sheet is in a semi-cured state and will melt and flow during pressing. The change in thickness will cause the rivet to shift or deform under the pressure of the press, thereby causing the core board to be offset, resulting in low inter-layer alignment after pressing. In this embodiment, the edge areas of the first high-frequency core board 10 and the sub-board 30 are provided with fusion zones. After fusion, the fusion zones are punched or drilled, and then fixed with rivets. Because the semi-cured sheet around the rivet has been melted and solidified during riveting, the thickness will not change during pressing, thus avoiding rivet shifting or rivet deformation during pressing, thereby improving inter-layer alignment.

[0077] In one embodiment, each core plate has multiple fusion zones. After the fusion zones are fused and solidified, at least half of the fusion zones are punched or drilled, and then riveted together to improve interlayer alignment between the high-frequency core plate 10 and the multiple sub-plates 30 after lamination. In actual processing, at least four fusion zones are provided, with rivet holes set at each of the four fusion locations. In another embodiment, six fusion zones are provided, with rivet holes set at four of the fusion locations.

[0078] The following Figure 1 The 8-layer board provided is used as an example to illustrate the high-frequency board manufacturing method provided by this application. The core board mentioned below can be the first high-frequency core board 10 or the daughter board 30. The high-frequency board manufacturing method includes: cutting, inner layer pattern transfer, inner layer AOI, browning, lamination, lamination, drilling, hole metallization, outer layer circuit production, solder mask, characterization, surface treatment and other post-processing.

[0079] Cutting: Cut the copper-clad laminate and prepreg (PP) sheets into the specified dimensions according to the production panel size requirements. This solution uses a stacked structure consisting of a first copper foil 20, a first prepreg, a first high-frequency core board 10, a second prepreg, a daughter board 30, a second prepreg, a daughter board 30, a second prepreg, and a second copper foil 60. The first prepreg adjacent to the signal layer is made of high-frequency material.

[0080] Inner layer circuits: According to conventional processes, the graphic circuits and board edge target patterns of the second metal layer L2 to the seventh metal layer L7 are normally produced, wherein the second metal layer L2 and the third metal layer L3 are arranged in the first high-frequency core board 10, and the signal line is formed in the second metal layer L2.

[0081] Inner layer AOI: Using optical principles, the etched circuit pattern is compared with the designed circuit pattern to check whether there are defects such as open circuit and short circuit.

[0082] Browning: Increase the roughness of the copper surface through chemical reaction, thereby enhancing the bonding strength between the prepreg and the copper surface during pressing.

[0083] Lamination and lamination: The copper foil, core board, and prepreg are arranged and laminated according to a preset lamination structure. In this embodiment, the lamination process also includes pre-fixing the core board and the prepreg sandwiched between the core boards, with the pre-fixing position being set in the board edge area.

[0084] Specifically, a fusion zone is created, where the second prepreg is melted and solidified, bonding the core sheet in the fusion zone. The fusion zone is then punched or drilled, and rivets are used for securement. Because the prepreg surrounding the rivet has already melted and solidified during riveting, its thickness remains unchanged during press-fitting, preventing rivet shifting or deformation during press-fitting and improving interlayer alignment.

[0085] In actual processing, at least four fusion zones are provided, with rivet holes set at each of the four fusion zones. In another embodiment, six fusion zones are provided, with rivet holes set at four of the fusion zones. During lamination, copper foil and prepreg are stacked on top and bottom of the riveted core board and pressed together to form a multilayer board.

[0086] Drilling and hole metallization: Drill holes in the laminated multilayer board. Since the signal lines are located in the second metal layer L2 and the BGA area for chip mounting is located in the first metal layer L1, blind vias are drilled in the first metal layer L1 and the second metal layer L2 to connect the signal layer with the outermost layer.

[0087] When drilling, the target pattern set on the second metal layer L2 is used as a drilling reference to ensure the alignment of the blind hole and the signal line in the second metal layer L2.

[0088] Shielding holes are drilled from the first metal layer L1 to the third metal layer L3. The shielding holes are located around the signal lines. When drilling, the target patterns set on the second metal layer L2 and the third metal layer L3 are used as drilling reference benchmarks to ensure the matching of the shielding holes.

[0089] In another embodiment, shielding holes have been set in the second metal layer L2 and the third metal layer L3, and then holes are drilled from the first metal layer L1 and the second metal layer L2 to connect the inner shielding holes. At this time, the drilling target pattern is based on the L2 layer.

[0090] The above-mentioned drilling is carried out by machining, which can be specifically laser drilling or mechanical drilling. When using laser drilling, in order to ensure that the hole shape is regular and complete, a high-energy, multi-gun drilling method is adopted to ensure that the dielectric layer is cut quickly and neatly, and at the same time, the energy is controlled to prevent excessive energy and cause the remaining energy to diffuse. There is no order of priority for drilling the above-mentioned blind holes and shielding holes. After drilling, the inside of the hole is also debonded, and chemical debonding and plasma debonding are used to make the hole wall roughness meet the requirements. After debonding, the hole metallization process is carried out to make the hole wall conductive. For example, copper plating can be used. It can be understood that in addition to processing blind holes and shielding holes that connect the first metal layer L1 and the second metal layer L2, metallized through holes that connect all layers, or blind holes that connect other specified circuit layers can also be processed without restriction.

[0091] Outer layer circuit fabrication: A masked etching process is used to transfer the outer layer pattern circuits. In this process, the first metal layer L1 is etched to form a window 101. The location of the window 101 is opposite the area where the signal line is located, reducing the interference of the outer copper layer on signal transmission and reception.

[0092] Solder mask and post-process: follow the conventional process control and will not be described in detail.

[0093] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A high-frequency board, characterized in that: The high-frequency board includes N metal layers sequentially spaced apart along a first direction, where N is an integer greater than 2; The first metal layer of the high-frequency board is provided on the outer surface of the high-frequency board, and a window portion is provided in the first metal layer; The second metal layer of the high-frequency board is provided on the first high-frequency core board, the second metal layer being the second outer metal layer, and a signal line is provided in the second metal layer, and the orthographic projection of the signal line on the first metal layer is located within the window portion; a first insulating dielectric layer is provided between the first metal layer and the first high-frequency core board, and the first insulating dielectric layer is made of high-frequency material; A metallized hole is provided in the high-frequency board, and the metallized hole conducts the first metal layer and the signal line; There are one or more window portions, and each window portion corresponds to one or more signal lines.

2. The high-frequency board according to claim 1, wherein: The high-frequency board is further provided with a metallized shielding hole, which is arranged around the signal line. The metallized shielding hole passes through the first metal layer, the second metal layer and extends to at least the third metal layer.

3. The high-frequency board according to claim 1, wherein: The first metal layer is made of a first copper foil. The high-frequency board further includes at least one second insulating medium layer and at least one sub-board stacked on a side of the first high-frequency core board facing away from the first metal layer.

4. The high-frequency board according to claim 3, characterized in that The high-frequency board further includes a second copper foil, which is arranged on a side of the sub-board facing away from the first copper foil.

5. The high-frequency board according to claim 3, characterized in that: The first high-frequency core board is a double-sided high-frequency core board or a single-sided high-frequency core board, and the material of the core board layer of the first high-frequency core board is at least one of polytetrafluoroethylene, hydrocarbon resin, and polyphenylene ether resin; the sub-board adopts a high-frequency core board or a non-high-frequency core board, and the material of the core board layer of the non-high-frequency core board is epoxy resin.

6. The high-frequency board according to any one of claims 1 to 5, characterized in that: A chip mounting area is provided in the first metal layer.

7. A method for manufacturing a high-frequency board, for manufacturing the high-frequency board according to any one of claims 1 to 6, characterized in that: The high frequency board production includes: A multilayer board is provided, comprising N metal layers sequentially spaced apart along a first direction, where N is an integer greater than 2, wherein a first metal layer of the multilayer board is disposed on a surface of the multilayer board, a second metal layer is disposed on a first high-frequency core board and a signal line is disposed in the second metal layer, the second metal layer being a sub-outer metal layer, and a first insulating dielectric layer is disposed between the first metal layer and the first high-frequency core board, the first insulating dielectric layer being made of a high-frequency material; Making metallized holes in the first metal layer and the second metal layer, wherein the metallized holes conduct electricity between the first metal layer and the signal line; A window portion is made on the first metal layer. There are one or more window portions. Each window portion corresponds to one or more signal lines. The orthographic projection of the signal line on the first metal layer is located within the window portion.

8. The method for manufacturing a high-frequency board according to claim 7, wherein: The multilayer board provided comprises: Providing a first copper foil, a first prepreg, the first high-frequency core board, at least one second prepreg and at least one daughter board; Fabricate inner layer circuits on the first high-frequency core board and at least one of the daughter boards; The first copper foil, the first prepreg, the first high-frequency core board, at least one second prepreg and at least one sub-board are stacked and pressed in sequence.

9. The method for manufacturing a high-frequency board according to claim 8, wherein: The high-frequency board manufacturing method further includes: Using target patterns provided in the second and third metal layers as drilling references, a shielding hole is drilled from one side of the first metal layer in the multilayer board; or, a first shielding sub-hole is provided in the second and third metal layers of the multilayer board, and a second shielding sub-hole is drilled from the first metal layer toward the second metal layer, the second shielding sub-hole being connected to the first shielding hole to form a shielding hole; The shielding hole is made into a metallized shielding hole.

10. The method for manufacturing a high-frequency board according to claim 8, wherein: Before laminating and pressing the boards, the high-frequency board manufacturing method further includes: The first high-frequency core board and the board edge area of the sub-board are provided with a fusion zone, and the second prepreg sandwiched between the fusion zones is fused; making a fixing hole in the fusion zone; The fixing holes are penetrated by rivets.

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