PCB manufacturing method and PCB
By directly forming a cavity structure on the PCB, the problems of long production process and high cost of air waveguide structural components are solved, realizing low-cost and high-efficiency cavity structure manufacturing, which is suitable for rapid verification of millimeter-wave radar PCBs.
Patent Information
- Application Number
- CN202511943009.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-02-24
AI Technical Summary
Existing technologies for producing air waveguide structural components involve long processes, high costs, and are not conducive to rapid verification, especially in the development stage of LOP chips.
By stacking the first board, the adhesive layer, and the second board to form a cavity structure, the plastic metallization process is avoided, and the air waveguide structure is directly fabricated on the PCB. The cavity structure is formed by using the gap opening in the adhesive layer and the conductive layer of the connection hole.
It simplifies the production process, reduces costs, and improves production efficiency, making it suitable for rapid verification of millimeter-wave radar PCBs.
Smart Images
Figure CN121568320A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of printed circuit board technology, and more particularly to a method for manufacturing a PCB and the PCB itself. Background Technology
[0002] In fields such as millimeter-wave radar, with the innovation and widespread adoption of LOP (Launch on Package) chips, the demand for air waveguide structures on PCBs (Printed Circuit Boards) for signal radiation is increasing. This technology aims to replace traditional high-frequency metal antennas with metal cavity channels of a specific shape. By utilizing the ultra-low Dk (Dielectric Constant, approximately 1.0) and Df (Dissipation Factor, approximately 0) properties of the air within the cavity, it achieves more precise transmission and reception of radiated signals. Furthermore, this design eliminates the need for expensive high-frequency materials, further reducing product manufacturing costs—a win-win situation.
[0003] Currently, the industry generally uses plastic metallization to produce the required air waveguide structural components. However, the plastic metallization process involves mold making, injection molding, and plastic metallization. Furthermore, the air waveguide structural components and the PCB motherboard are produced separately, and it is necessary to combine the air waveguide structural components with the PCB motherboard separately, resulting in a long production process and high costs. Summary of the Invention
[0004] This application provides a PCB manufacturing method and a PCB, which solves the problems of long production process and high cost of the air waveguide structure components currently produced using plastic metallization.
[0005] In a first aspect, embodiments of this application provide a method for manufacturing a PCB, comprising: A first plate, an adhesive layer, and a second plate are stacked together, with the adhesive layer located between the first and second plates. The first plate has a first connecting hole, and a first conductive layer is provided on the inner wall of the first connecting hole. The adhesive layer has a clearance window. The second plate has a second connecting hole located on the side of the clearance window opposite to the first connecting hole. A second conductive layer is provided on the inner wall of the second connecting hole. The side of the second plate facing the first plate also has a connecting pad. The clearance window exposes the connecting pad, and the connecting pad is connected to the second conductive layer. The first plate, the adhesive layer, and the second plate are pressed together to connect the first connecting hole, the clearance window, and the second connecting hole, forming a cavity structure.
[0006] In some embodiments, the first connection hole includes a first hole and a second hole that are connected to each other. The first hole is located on the side of the second hole away from the second plate. The diameter of the first hole is smaller than the diameter of the second hole. The inner wall of the first hole is provided with a first connection layer, and the inner wall of the second hole is provided with a second connection layer. The first conductive layer includes the first connection layer and the second connection layer.
[0007] In some embodiments, the PCB fabrication method further includes, prior to stacking the first board, the adhesive layer, and the second board together: Provide substrate; The first hole and the second hole are processed on the substrate; The first connecting layer is disposed on the inner wall of the first hole, and the second connecting layer is disposed on the inner wall of the second hole to obtain the first plate, wherein the first connecting layer and the second connecting layer are connected.
[0008] In some embodiments, the process of forming the first hole and the second hole on the substrate includes: A process hole is formed on the substrate, and the process hole penetrates the substrate. A second hole, coaxial with the process hole, is machined on one side of the substrate, and the remaining process hole is the first hole.
[0009] In some embodiments, when the first hole and the second hole are processed on the substrate, a first positioning hole is simultaneously processed on the substrate; when the first plate, the adhesive layer and the second plate are stacked together, the first plate, the adhesive layer and the second plate are aligned through the first positioning hole.
[0010] In some embodiments, the second plate is provided with a second positioning hole, and the adhesive layer is provided with a connection positioning hole; the alignment of the first plate, the adhesive layer, and the second plate through the first positioning hole includes: A mold is provided, the mold including locating pins; Insert the positioning pin into the second positioning hole, the connecting positioning hole, and the first positioning hole.
[0011] In some embodiments, the first board includes a first sub-board, a dielectric layer and a second sub-board stacked together, the first hole is disposed on the first sub-board and the second hole is disposed on the second sub-board, and the dielectric layer is provided with a clearance opening corresponding to the position of the first hole.
[0012] In some embodiments, the PCB fabrication method further includes, prior to stacking the first board, the adhesive layer, and the second board together: A first hole and a second hole are respectively machined on the first sub-plate and the second sub-plate; a first connecting layer and a second connecting layer are respectively provided on the inner wall of the first hole and the inner wall of the second hole; Alternatively, a first hole and a second hole are machined on the first sub-board and the second sub-board respectively; the first sub-board, the dielectric layer and the second sub-board are pressed together; the first connecting layer is provided on the inner wall of the first hole and the second connecting layer is provided on the inner wall of the second hole to obtain the first board, wherein the first connecting layer and the second connecting layer are connected.
[0013] In some embodiments, the outer edge of the connecting pad is provided with a recess, which surrounds the second connecting hole.
[0014] Secondly, embodiments of this application provide a PCB, which is manufactured by the PCB manufacturing method described in the first aspect.
[0015] The PCB manufacturing method provided in this application has the following advantages: First, a first board, an adhesive layer, and a second board are stacked together, with the adhesive layer located between the first and second boards. The first board has a first connecting hole, and the inner wall of the first connecting hole is provided with a first conductive layer. The adhesive layer has a clearance window. The second board has a second connecting hole, located on the side of the clearance window away from the first connecting hole. The inner wall of the second connecting hole is provided with a second conductive layer. The side of the second board facing the first board also has a connecting pad. The clearance window exposes the connecting pad, and the connecting pad is connected to the second conductive layer. Then, the first board, the adhesive layer, and the second board are pressed together, so that the first connecting hole, the clearance window, and the second connecting hole are connected to form a cavity structure. Therefore, it is relatively convenient to manufacture a PCB with a cavity structure, without the need to use plastic metallization to produce the required air waveguide structure. The production process is shorter and the cost is lower.
[0016] The advantages of the PCB provided in this application compared to the prior art can be found in the description of the advantages of the PCB manufacturing method provided in this application compared to the prior art, which will not be repeated here. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1This is a flowchart of a PCB manufacturing method in one embodiment of this application; Figure 2 This is a schematic diagram of a process hole and a first positioning hole being processed on a substrate in one embodiment of this application; Figure 3 Is Figure 2 A schematic diagram showing the fabrication of a second hole on the substrate; Figure 4 Is Figure 3 The schematic diagram shows a first conductive material disposed on the inner wall of the first hole of the substrate and a second conductive material disposed on the inner wall of the second hole. Figure 5 Is Figure 4 A schematic diagram of a first plate is obtained by depositing a first anti-oxidation layer on a first conductive material and a second anti-oxidation layer on a second conductive material on a first conductive material. Figure 6 It is Figure 5 The diagram shows the first plate, the adhesive layer, the second plate, and the mold stacked together. Figure 7 Yes Figure 6 A schematic diagram showing the pressing of the first plate, the adhesive layer, and the second plate; Figure 8 Yes Figure 7 The diagram shows the curing process of the first plate, the adhesive layer, and the second plate. Figure 9 yes Figure 8 The diagram shows the structure of the PCB formed by the first board, the adhesive layer, and the second board. Figure 10 yes Figure 9 The diagram shows the connection between the PCB and the LOP packaged chip.
[0019] The markings in the diagram mean: 101. Substrate; 102. Process hole; 10. First board; 11. Metal layer; 12. Insulating dielectric layer; 13. First hole; 131. First conductive material; 132. First anti-oxidation layer; 14. Second hole; 141. Second conductive material; 142. Second anti-oxidation layer; 15. First positioning hole; 20. Adhesive layer; 21. Avoidance window opening; 22. Connection positioning hole; 30. Second board; 301. Connecting pad; 31. Second connecting hole; 311. Third conductive material; 312. Third anti-oxidation layer; 32. Second positioning hole; 33. First circuit layer; 34. Second circuit layer; 35. Solder resist ink; 351. Solder resist opening; 40. Mold; 41. Positioning pin; 50. High-speed press; 60. Nitrogen-pressure oven; 70. LOP packaged chip. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0021] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.
[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0023] In this specification, references to "one embodiment," "some embodiments," or simply "embodiment" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. Furthermore, in one or more embodiments, specific features, structures, or characteristics may be combined in any suitable manner.
[0024] In fields such as millimeter-wave radar, with the innovation and widespread adoption of LOP chips, the demand for air waveguide structures on PCBs for signal radiation is increasing. This technology aims to replace traditional high-frequency metal antennas with metal cavity channels of a specific shape. By utilizing the ultra-low Dk (Dielectric Constant, approximately 1.0) and Df (Dissipation Factor, approximately 0) properties of air within the cavity, it achieves more precise transmission and reception of radiated signals. Furthermore, this design eliminates the need for expensive high-frequency materials, further reducing product manufacturing costs—a win-win situation.
[0025] Currently, the industry generally uses plastic metallization to produce the required air waveguide structural components. However, the plastic metallization process involves mold making, injection molding, and plastic metallization. Furthermore, the air waveguide structural components and the PCB motherboard are produced separately, and it is necessary to combine the air waveguide structural components with the PCB motherboard. This results in a long production process, high costs, and is not conducive to rapid verification during the R&D stage. At present, the LOP core board is still in the development stage and multiple solutions are needed in a short period of time. The above-mentioned drawbacks are amplified at this stage.
[0026] In view of this, this application provides a PCB manufacturing method and a PCB. First, a first board, an adhesive layer, and a second board are stacked together, with the adhesive layer located between the first and second boards. The first board has a first connecting hole, and the inner wall of the first connecting hole is provided with a first conductive layer. The adhesive layer has a recessed opening. The second board has a second connecting hole located on the side of the recessed opening opposite to the first connecting hole. The inner wall of the second connecting hole is provided with a second conductive layer. The side of the second board facing the first board also has a connecting pad. The recessed opening exposes the connecting pad, which is connected to the second conductive layer. Then, the first board, adhesive layer, and second board are pressed together, so that the first connecting hole, the recessed opening, and the second connecting hole are connected to form a cavity structure. Therefore, a PCB with a cavity structure can be manufactured relatively easily, without the need for plastic metallization to produce the required air waveguide structure. The production process is shorter and the cost is lower.
[0027] To illustrate the technical solution of this application, the following description is provided in conjunction with specific accompanying drawings and embodiments.
[0028] Please refer to Figures 1 to 5 In a first aspect, embodiments of this application provide a method for manufacturing a PCB, comprising: S100: The first plate 10, the adhesive layer 20, and the second plate 30 are stacked together. The adhesive layer 20 is located between the first plate 10 and the second plate 30. The first plate 10 is provided with a first connecting hole. The inner wall of the first connecting hole is provided with a first conductive layer. The adhesive layer 20 is provided with a clearance window 21. The second plate 30 is provided with a second connecting hole 31. The second connecting hole 31 is located on the side of the clearance window 21 away from the first connecting hole. The inner wall of the second connecting hole 31 is provided with a second conductive layer. The side of the second plate 30 facing the first plate 10 is also provided with a connecting pad 301. The clearance window 21 exposes the connecting pad 301, and the connecting pad 301 is connected to the second conductive layer.
[0029] Both the first board 10 and the second board 30 can be single-sided or double-sided copper-clad laminates, or they can be bare boards or multilayer boards. The adhesive layer 20 may include fiberglass cloth and resin, or, if it is a prepreg or thermosetting adhesive, it can be processed into a shape that matches the first board 10 and the second board 30 using a laser cutting machine or a stamping machine. The materials of the first conductive layer and the second conductive layer are both copper, aluminum, silver, nickel, or tin, etc. The first connecting hole and the second connecting hole can both be regular or irregular in shape.
[0030] S200: Press the first plate 10, the adhesive layer 20 and the second plate 30 together so that the first connecting hole, the clearance window 21 and the second connecting hole 31 are connected and form a cavity structure.
[0031] The first plate 10, the adhesive layer 20, and the second plate 30 can be pressed using a high-speed press 50 and then baked and cured using a nitrogen pressure oven 60. After the first connecting hole, the clearance window 21, and the second connecting hole 31 are connected to form a cavity structure, the inner wall of the cavity structure includes a first conductive layer and a second conductive layer. The second connecting layer can be spaced apart from the second conductive layer to form a discontinuous structure.
[0032] As can be seen from the above, the PCB manufacturing method provided in this application involves first stacking a first board 10, an adhesive layer 20, and a second board 30 together, with the adhesive layer 20 located between the first board 10 and the second board 30. The first board 10 has a first connecting hole, and the inner wall of the first connecting hole has a first conductive layer. The adhesive layer 20 has a clearance window 21. The second board 30 has a second connecting hole 31 located on the side of the clearance window 21 away from the first connecting hole. The inner wall of the second connecting hole 31 has a second conductive layer. The side of the second board 30 facing the first board 10 also has a connecting... The pad 301 and the recessed window 21 expose the connecting pad 301, which is connected to the second conductive layer. Then, the first board 10, the adhesive layer 20 and the second board 30 are pressed together, so that the first connecting hole, the recessed window 21 and the second connecting hole 31 are connected and form a cavity structure. Therefore, it is relatively easy to manufacture a PCB with a cavity structure, which can be used as a waveguide millimeter-wave radar PCB. There is no need to use plastic metallization to produce the required air waveguide structure components. The production process is shorter and the cost is lower, which improves production efficiency. The issues of cost and timeliness are greatly improved and reduced.
[0033] It should be noted that, in addition to the first board 10, the second board 30, and the adhesive layer 20, the PCB with the cavity structure can also include other laminated boards, depending on the shape of the cavity structure. The number of cavity structures is determined by the chip design. Currently, a waveguide millimeter-wave radar PCB with a "4-transmit, 4-receive" design would have eight cavity structures.
[0034] Optionally, the adhesive layer 20 is a non-flowing thermosetting adhesive with a thickness of ≤25µm.
[0035] In this way, the spacing between the second connecting layer and the second conductive layer can be controlled within 25um, without affecting signal transmission. At the same time, its non-flow properties can effectively prevent the formed adhesive from overflowing into the cavity structure.
[0036] It should be noted that the size of the recessed opening 21 is 0.025mm larger on each side than the first connecting hole and the second connecting hole 31, in order to prevent the adhesive layer 20 from overflowing into the cavity structure due to misalignment and affecting signal transmission.
[0037] Optionally, the second connecting layer protrudes from the side of the first plate 10 facing the second plate 30 and is located within the recessed window 21.
[0038] With this configuration, when the first plate 10, the adhesive layer 20 and the second plate 30 are pressed together, the portion of the second connecting layer protruding from the side of the first plate 10 facing the second plate 30 can block the flow of adhesive formed by the adhesive layer 20, thus preventing the adhesive from entering the interior of the cavity structure.
[0039] As an implementable method, the first connecting hole includes a first hole 13 and a second hole 14 that are connected to each other. The first hole 13 is located on the side of the second hole 14 away from the second plate 30. The diameter of the first hole 13 is smaller than the diameter of the second hole 14. A first connecting layer is provided on the inner wall of the first hole 13, and a second connecting layer is provided on the inner wall of the second hole 14. The first conductive layer includes the first connecting layer and the second connecting layer.
[0040] This configuration allows the first hole 13, the second hole 14, the clearance window 21, and the second connecting hole 31 to be connected and form a cavity structure. The inner wall of the cavity structure includes a first connecting layer, a second connecting layer, and a second conductive layer.
[0041] It should be noted that the first hole 13 and the second hole 14 penetrate the two opposite sides of the first board 10, respectively, and the second connecting hole 31 penetrates the connecting pad 301. The materials of the first and second connecting layers are copper, aluminum, silver, nickel, or tin, etc. The second connecting hole 31 and the second hole 14 serve as waveguide channels, and the first hole 13 is used for signal radiation. Multiple first holes 13, second holes 14, and second connecting holes 31 can be provided and configured in a one-to-one correspondence. The first hole 13, second hole 14, and second connecting hole 31 are not limited to circular holes; they can also be holes of other shapes.
[0042] Please refer to Figures 2 to 5 In some embodiments, the PCB fabrication method further includes, before stacking the first board 10, the adhesive layer 20, and the second board 30 together: First, a substrate 101 is provided.
[0043] The substrate 101 can be a single-sided copper-clad laminate, a double-sided copper-clad laminate, or a bare board.
[0044] Next, a first hole 13 and a second hole 14 are formed on the substrate 101.
[0045] The first hole 13 and the second hole 14 can be processed on the substrate 101 by mechanical processing or laser ablation.
[0046] Next, a first connecting layer is provided on the inner wall of the first hole 13, and a second connecting layer is provided on the inner wall of the second hole 14 to obtain the first plate 10.
[0047] The first connecting layer can be formed on the inner wall of the first hole 13 by chemical deposition or copper plating, and the second connecting layer can be formed on the inner wall of the second hole 14.
[0048] By adopting the above method, the first plate 10 can be produced relatively easily.
[0049] It should be noted that the production method of the second board 30 is similar to that of the first board 10.
[0050] Optionally, a first hole 13 and a second hole 14 are formed on the substrate 101, including: A process hole 102 is processed on the substrate 101, and the process hole 102 penetrates the substrate 101. First, a process hole 102 is processed on the substrate 101, and the process hole 102 penetrates the substrate 101. Next, a second hole 14 coaxial with the process hole 102 is processed on one side of the substrate 101, and the remaining process hole 102 is the first hole 13.
[0051] By adopting the above scheme, the first hole 13 and the second hole 14 can be processed on the substrate 101 relatively easily.
[0052] It is understandable that the diameter of the second hole 14 is larger than the diameter of the process hole 102, and the diameter of the first hole 13 is equal to the diameter of the process hole 102.
[0053] As one possible implementation, the substrate 101 includes two metal layers 11 and an insulating dielectric layer 12 disposed between the two metal layers 11. The metal layers 11 may be copper layers, and the insulating dielectric layer 12 may include resin and fiberglass cloth, etc. The resin is usually epoxy resin, polyimide resin, polytetrafluoroethylene resin, etc. A first hole 13 penetrates one of the metal layers 11, and a second hole 14 penetrates the other metal layer 11. After a first connecting layer is provided on the inner wall of the first hole 13 and a second connecting layer is provided on the inner wall of the second hole 14, the metal layers 11 outside the first hole 13 and the second hole 14 are removed by film exposure and etching, and then the shape required by the shipping unit design is milled.
[0054] Optionally, the first connecting layer includes a first conductive material 131 and a first anti-oxidation layer 132, and the second connecting layer includes a second conductive material 141 and a second anti-oxidation layer 142; the first connecting layer is disposed on the inner wall of the first hole 13, and the second connecting layer is disposed on the inner wall of the second hole 14, including: First, a first conductive material 131 is disposed on the inner wall of the first hole 13, and a second conductive material 141 is disposed on the inner wall of the second hole 14.
[0055] Specifically, a conductive seed layer can be formed by chemical deposition, followed by electroplating to thicken it. A first conductive material 131 is deposited on the inner wall of the first hole 13, and a second conductive material 141 is deposited on the inner wall of the second hole 14. The formation of the conductive seed layer can also be achieved using other feasible methods, not limited to chemical deposition.
[0056] Next, a first anti-oxidation layer 132 is deposited on the first conductive material 131, and a second anti-oxidation layer 142 is deposited on the second conductive material 141.
[0057] Specifically, a first anti-oxidation layer 132 can be deposited on the first conductive material 131 through surface treatment, and a second anti-oxidation layer 142 can be deposited on the second conductive material 141. The materials of the first anti-oxidation layer 132 and the second anti-oxidation layer 142 can both be set to tin or silver, etc.
[0058] This configuration allows the first conductive material 131 to be prevented from oxidizing through the first anti-oxidation layer 132, and the second conductive material 141 to be prevented from oxidizing through the second anti-oxidation layer 142.
[0059] It is understood that the second conductive layer includes a third conductive material 311 and a third anti-oxidation layer 312, with the third anti-oxidation layer 312 preventing the third conductive material 311 from oxidizing. The material and manufacturing method of the second conductive layer can be similar to those of the first connecting layer.
[0060] Optionally, the outer edge of the connecting pad 301 is provided with a recess (not shown in the figure), and the recess surrounds the second connecting layer.
[0061] This design allows the recessed portion to accommodate the adhesive flow formed during pressing of the adhesive layer 20, preventing the adhesive from entering the interior of the cavity structure.
[0062] It should be noted that the recessed portion can be configured as a groove, which is formed by etching or machining, and is used to accommodate the adhesive flow formed during the pressing of the adhesive layer 20.
[0063] Please refer to Figures 6 to 9 When the first hole 13 and the second hole 14 are processed on the substrate 101, the first positioning hole 15 is processed on the substrate 101 simultaneously; when the first plate 10, the adhesive layer 20 and the second plate 30 are stacked together, the first plate 10, the adhesive layer 20 and the second plate 30 are aligned through the first positioning hole 15.
[0064] By adopting the above scheme, the relative positional accuracy of the first hole 13, the second hole 14 and the first positioning hole 15 can be guaranteed, thereby improving the alignment accuracy of the first hole 13, the second hole 14 and the second connecting hole 31 when the first plate 10, the adhesive layer 20 and the second plate 30 are stacked together.
[0065] It should be noted that the positional accuracy of the first hole 13, the second hole 14, and the first positioning hole 15 can meet the tolerance of ±0.05mm.
[0066] Optionally, the second plate 30 is provided with a second positioning hole 32, and the adhesive layer 20 is provided with a connecting positioning hole 22; the first plate 10, the adhesive layer 20, and the second plate 30 are aligned through the first positioning hole 15, including: First, a mold 40 is provided, which includes a locating pin 41.
[0067] Next, insert the positioning pin 41 into the second positioning hole 32, connecting the positioning hole 22 and the first positioning hole 15.
[0068] By adopting the above scheme, the alignment accuracy of the first hole 13, the second hole 14, and the second connecting hole 31 can be improved when the first plate 10, the adhesive layer 20, and the second plate 30 are stacked together (the alignment deviation can be controlled within 0.05mm, and the alignment deviation Cpk > 1.67 for multiple batches). This ensures that the first hole 13, the second hole 14, the clearance window 21, and the second connecting hole 31 are connected and form a cavity structure, thus meeting the waveguide antenna transmission accuracy requirements.
[0069] It should be noted that at least two positioning pins 41 can be provided. The diameter of the pin is 0.025mm smaller than the diameter of the second positioning hole 32, the connecting positioning hole 22 and the first positioning hole 15, so as to facilitate the insertion of the positioning pin 41 into the second positioning hole 32, the connecting positioning hole 22 and the first positioning hole 15.
[0070] It is understandable that the machining methods of the second connecting hole 31 and the second positioning hole 32, as well as the machining methods of the clearance window 21 and the connecting positioning hole 22, can be similar to the machining methods of the first hole 13, the second hole 14, and the first positioning hole 15. The positional accuracy of the second connecting hole 31 and the second positioning hole 32 can meet the tolerance of ±0.05mm.
[0071] For example, the first plate 10, the adhesive layer 20, the second plate 30, and the mold 40 can be placed together in a high-pressure press 50 and pre-pressed for 90 seconds under a pressure of 0.5 kg / cm²-0.7 kg / cm² and a temperature of 80℃-90℃. This allows the thermosetting adhesive of the adhesive layer 20 to initially melt and form a certain adhesive force. After cooling, the pre-fixation is completed. Then, the combined plate after the first plate 10, adhesive layer 20, and second plate 30 are bonded together is placed in a nitrogen pressure oven 60 and baked for 1 hour under a pressure of >2 kg / cm² and a temperature of 150℃. The thermosetting adhesive is finally cured by nitrogen pressure baking, without damaging the first anti-oxidation layer 132 and the second anti-oxidation layer 142 obtained by surface treatment.
[0072] In other embodiments, the first plate 10 includes a first sub-plate, a dielectric layer and a second sub-plate stacked together, a first hole 13 is provided on the first sub-plate, a second hole 14 is provided on the second sub-plate, and the dielectric layer is provided with a clearance opening corresponding to the position of the first hole 13.
[0073] By adopting the above scheme, it is relatively easy to form a first plate 10 with a first connecting hole through a first sub-plate and a second sub-plate.
[0074] It should be noted that both the first and second sub-boards can be single-sided or double-sided copper-clad laminates, or they can be bare boards or multilayer boards. The dielectric layer may include fiberglass cloth and resin, such as prepreg or thermosetting adhesive.
[0075] As a feasible method, before stacking the first board 10, the adhesive layer 20, and the second board 30 together, the PCB fabrication method further includes: First, the first hole 13 and the second hole 14 are machined on the first daughter plate and the second daughter plate respectively.
[0076] Secondly, a first connecting layer and a second connecting layer are respectively provided on the inner wall of the first hole 13 and the inner wall of the second hole 14.
[0077] With this setup, the first board 10 can be obtained relatively easily after stacking the first sub-board, the dielectric layer, and the second sub-board together.
[0078] As a feasible method, before stacking the first board 10, the adhesive layer 20, and the second board 30 together, the PCB fabrication method further includes: First, the first hole 13 and the second hole 14 are machined on the first daughter plate and the second daughter plate respectively.
[0079] Next, the first sub-board, the dielectric layer, and the second sub-board are pressed together.
[0080] Then, a first connecting layer is provided on the inner wall of the first hole 13, and a second connecting layer is provided on the inner wall of the second hole 14 to obtain the first plate 10, wherein the first connecting layer and the second connecting layer are connected.
[0081] This setup makes it relatively easy to create the first board 10.
[0082] Please refer to Figures 6 to 9 In some embodiments, a connection conductive layer is provided on the side of the second board 30 facing the first board 10. The connection conductive layer includes a first circuit layer 33 and a connection anti-oxidation layer (not shown in the figure). Solder resist ink 35 is provided on the first circuit layer 33. Solder resist ink 35 is provided with solder resist openings 351. The connection anti-oxidation layer covers a portion of the first circuit layer 33. The solder resist openings 351 expose the connection anti-oxidation layer. The connection anti-oxidation layer and the first circuit layer 33 it covers form a connection pad 301.
[0083] By adopting the above solution, it is possible to avoid the adhesive layer 20 coming into contact with a large area of the connecting anti-oxidation layer, which would result in poor adhesion between the adhesive layer 20 and the connecting anti-oxidation layer.
[0084] For example, if the material connecting the anti-oxidation layer is tin, the tin will remelt during subsequent soldering, causing poor adhesion between the adhesive layer 20 and the tin, resulting in it bursting open. If the material connecting the anti-oxidation layer is silver, the silver surface itself is relatively smooth, and its adhesion to the adhesive layer 20 is also poor, causing it to burst open as well.
[0085] For example, the thickness of solder resist ink 35 is controlled at 10um-20um.
[0086] Please refer to Figure 10 Optionally, a second circuit layer 34 is provided on the side of the second plate 30 away from the adhesive layer 20, and the second conductive layer is connected to the second circuit layer 34.
[0087] This configuration allows the second conductive layer to be electrically connected to the second circuit layer 34 and the LOP packaged chip 70, resulting in an integrated LOP packaged waveguide millimeter-wave radar PCB.
[0088] It is understandable that the materials of the first connecting layer, the second connecting layer, and the second conductive layer can be the same, and the different shapes and distribution positions of the first hole 13, the second hole 14, and the second connecting hole 31 can achieve different effects.
[0089] Secondly, embodiments of this application provide a PCB, which is manufactured using the PCB manufacturing method of the first aspect.
[0090] The PCB provided in this application embodiment is manufactured by first stacking a first board 10, an adhesive layer 20, and a second board 30 together, with the adhesive layer 20 located between the first board 10 and the second board 30. The first board 10 has a first connecting hole, and the inner wall of the first connecting hole has a first conductive layer. The adhesive layer 20 has a clearance window 21. The second board 30 has a second connecting hole 31, located on the side of the clearance window 21 away from the first connecting hole. The inner wall of the second connecting hole 31 has a second conductive layer. The second board 30 is also provided with a connecting pad 301 on the side facing the first board 10. The avoidance window 21 exposes the connecting pad 301, and the connecting pad 301 is connected to the second conductive layer. Then, the first board 10, the adhesive layer 20 and the second board 30 are pressed together, so that the first connecting hole, the avoidance window 21 and the second connecting hole 31 are connected and form a cavity structure. Therefore, it is relatively easy to manufacture a PCB with a cavity structure without using plastic metallization to produce the required air waveguide structure. The production process is shorter and the cost is lower.
[0091] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A method for manufacturing a PCB, characterized in that, include: A first plate, an adhesive layer, and a second plate are stacked together, with the adhesive layer located between the first and second plates. The first plate has a first connecting hole, and a first conductive layer is provided on the inner wall of the first connecting hole. The adhesive layer has a clearance window. The second plate has a second connecting hole located on the side of the clearance window opposite to the first connecting hole. A second conductive layer is provided on the inner wall of the second connecting hole. The side of the second plate facing the first plate also has a connecting pad. The clearance window exposes the connecting pad, and the connecting pad is connected to the second conductive layer. The first plate, the adhesive layer, and the second plate are pressed together to connect the first connecting hole, the clearance window, and the second connecting hole, forming a cavity structure.
2. The PCB manufacturing method according to claim 1, characterized in that, The first connecting hole includes a first hole and a second hole that are connected to each other. The first hole is located on the side of the second hole that is away from the second plate. The diameter of the first hole is smaller than the diameter of the second hole. The inner wall of the first hole is provided with a first connecting layer, and the inner wall of the second hole is provided with a second connecting layer. The first conductive layer includes the first connecting layer and the second connecting layer.
3. The PCB manufacturing method according to claim 2, characterized in that, Before stacking the first board, the adhesive layer, and the second board together, the PCB manufacturing method further includes: Provide substrate; The first hole and the second hole are processed on the substrate; The first connecting layer is disposed on the inner wall of the first hole, and the second connecting layer is disposed on the inner wall of the second hole to obtain the first plate, wherein the first connecting layer and the second connecting layer are connected.
4. The PCB manufacturing method according to claim 3, characterized in that, The process of machining the first hole and the second hole on the substrate includes: A process hole is formed on the substrate, and the process hole penetrates the substrate. A second hole, coaxial with the process hole, is machined on one side of the substrate, and the remaining process hole is the first hole.
5. The PCB manufacturing method according to claim 3, characterized in that, When the first hole and the second hole are processed on the substrate, the first positioning hole is simultaneously processed on the substrate; when the first plate, the adhesive layer and the second plate are stacked together, the first plate, the adhesive layer and the second plate are aligned through the first positioning hole.
6. The PCB manufacturing method according to claim 5, characterized in that, The second plate is provided with a second positioning hole, and the adhesive layer is provided with a connecting positioning hole; the alignment of the first plate, the adhesive layer, and the second plate through the first positioning hole includes: A mold is provided, the mold including locating pins; Insert the positioning pin into the second positioning hole, the connecting positioning hole, and the first positioning hole.
7. The PCB manufacturing method according to claim 2, characterized in that, The first board includes a first sub-board, a dielectric layer and a second sub-board stacked together. The first hole is provided on the first sub-board and the second hole is provided on the second sub-board. The dielectric layer is provided with a clearance opening corresponding to the position of the first hole.
8. The PCB manufacturing method according to claim 7, characterized in that, Before stacking the first board, the adhesive layer, and the second board together, the PCB manufacturing method further includes: A first hole and a second hole are respectively machined on the first sub-plate and the second sub-plate; a first connecting layer and a second connecting layer are respectively provided on the inner wall of the first hole and the inner wall of the second hole; Alternatively, a first hole and a second hole are machined on the first sub-board and the second sub-board respectively; the first sub-board, the dielectric layer and the second sub-board are pressed together; the first connecting layer is provided on the inner wall of the first hole and the second connecting layer is provided on the inner wall of the second hole to obtain the first board, wherein the first connecting layer and the second connecting layer are connected.
9. The method for manufacturing a PCB according to any one of claims 1 to 8, characterized in that, The outer edge of the connecting pad is provided with a recessed portion, which surrounds the second connecting hole.
10. A PCB, characterized in that, The PCB is manufactured by the PCB manufacturing method as described in any one of claims 1 to 9.