Multilayer circuit board and manufacturing method thereof

Abstract

The invention provides a multilayer circuit board and a manufacturing method thereof, and the method comprises the steps: providing an intermediate structure which comprises a circuit board assembly, a dielectric layer and a first metal layer, the dielectric layer and the first metal layer are located in the circuit board assembly, and the dielectric layer is located at one side, away from the circuit board assembly, of the first metal layer; a first through hole is formed, the first through hole penetrates through the circuit board assembly and the dielectric layer, and the hole wall of the first through hole and the first metal layer are arranged at an interval; a second metal layer is formed, the second metal layer covers the hole wall of the first through hole, and the first metal layer, the second metal layer and the dielectric layer jointly form a capacitor structure; and the middle structure and the second metal layer jointly form a multilayer circuit board with a capacitor structure. The method is simple in step, does not need to form a capacitor structure through surface mounting, and is lower in cost. According to the multilayer circuit board formed by the method, the capacitor structure is a coaxial structure, the capacitor structure with large capacity can be formed, and the performance of the multilayer circuit board with the capacitor structure is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit board manufacturing, in particular to a multilayer circuit board and a manufacturing method thereof. BACKGROUND

[0002] As today's electronic products are developing towards short, small, thin and light, the density requirements for PCB as a component motherboard are also becoming higher and higher. Passive component embedding technology can greatly reduce the number of components while improving electromagnetic performance.

[0003] In the related art, the embedded capacitor technology of embedding a capacitor element inside a substrate is an important solution for miniaturizing electronic systems. It is usually used in microphones and wearable electronic products, and plays a role in filtering, timing, decoupling and electrical energy storage. Its main advantages are to improve the stability and reliability of electronic systems, reduce the cost of products and reduce the physical size of products.

[0004] However, the multilayer circuit board formed by the above-mentioned embedded capacitor technology has high processing difficulty, which is not conducive to widespread promotion and application. SUMMARY

[0005] In order to solve at least one problem mentioned in the background art, the present application provides a multilayer circuit board and a manufacturing method thereof, aiming to solve the technical problem that the multilayer circuit board formed by the embedded capacitor technology in the related art has high processing difficulty, which is not conducive to widespread promotion and application.

[0006] In order to achieve the above-mentioned purpose, in a first aspect, the present application provides a manufacturing method of a multilayer circuit board, comprising:

[0007] providing an intermediate structure, the intermediate structure comprising a circuit board assembly, a dielectric layer and a first metal layer, the dielectric layer and the first metal layer being located in the circuit board assembly, and the dielectric layer being located on the side of the first metal layer away from the circuit board assembly;

[0008] forming a first via, the first via penetrating the circuit board assembly and the dielectric layer, the hole wall of the first via being spaced apart from the first metal layer;

[0009] forming a second metal layer, the second metal layer covering the hole wall of the first via, the first metal layer, the second metal layer and the dielectric layer together forming a capacitor structure; the intermediate structure and the second metal layer together forming a multilayer circuit board with the capacitor structure.

[0010] In the manufacturing method of the multilayer circuit board, optionally, the intermediate structure further comprises a third metal layer located on opposite sides of the dielectric layer, the third metal layer is arranged in a spaced manner with the dielectric layer, and the extending direction of the third metal layer intersects with the extending direction of the second metal layer.

[0011] The second metal layer is connected with the third metal layer.

[0012] In the manufacturing method of the multilayer circuit board, optionally, the number of the capacitor structures is plural.

[0013] Along the surface extending direction of the third metal layer, the plural capacitor structures are arranged in a spaced manner, and adjacent capacitor structures are connected through the third metal layer.

[0014] And / or, along the thickness direction of the circuit board assembly, the plural capacitor structures are arranged in a spaced manner, and adjacent capacitor structures are connected through the third metal layer.

[0015] In the manufacturing method of the multilayer circuit board, optionally, the intermediate structure comprises plural dielectric layers and plural first metal layers, and the plural dielectric layers are arranged in a spaced manner through the plural first metal layers.

[0016] In the manufacturing method of the multilayer circuit board, optionally, the intermediate structure comprises:

[0017] Providing a circuit board assembly;

[0018] Forming a second through hole, the axis of the second through hole extends along the thickness direction of the circuit board assembly;

[0019] Forming the first metal layer, the first metal layer covers the hole wall of the second through hole;

[0020] Forming the dielectric layer, the dielectric layer is located in the second through hole, and the dielectric layer is located on the side of the first metal layer away from the circuit board assembly;

[0021] Stacking a semi-solid sheet and a third metal layer on the side of the dielectric layer away from the circuit board assembly in sequence, and the dielectric layer, the first metal layer, the circuit board assembly, the semi-solid sheet and the third metal layer jointly form the intermediate structure.

[0022] In the manufacturing method of the multilayer circuit board, optionally, when the intermediate structure comprises plural dielectric layers and plural first metal layers,

[0023] After forming the dielectric layer, further comprising:

[0024] Repeating the forming of the second via, the first metal layer and the dielectric layer on the dielectric layer.

[0025] In the method for manufacturing the multilayer circuit board, optionally, the plurality of dielectric layers are made of the same material or different materials.

[0026] In the method for manufacturing the multilayer circuit board, optionally, the providing the circuit board assembly comprises:

[0027] providing a circuit board substrate covered with a copper layer;

[0028] performing a patterning process on the circuit board substrate to form a circuit pattern;

[0029] sequentially forming the prepreg and a fourth metal layer on a side of the circuit pattern away from the circuit board substrate;

[0030] heating the prepreg, the prepreg filling the circuit pattern to form the circuit board assembly.

[0031] In the method for manufacturing the multilayer circuit board, optionally, the first metal layer is connected to the fourth metal layer.

[0032] In a second aspect, the application further provides a multilayer circuit board manufactured by the method for manufacturing the multilayer circuit board.

[0033] The multilayer circuit board and the method for manufacturing the multilayer circuit board provided by the application comprise the following steps: providing an intermediate structure, the intermediate structure comprising a circuit board assembly, a dielectric layer and a first metal layer, the dielectric layer and the first metal layer being located in the circuit board assembly, and the dielectric layer being located on a side of the first metal layer away from the circuit board assembly; forming a first via, the first via penetrating the circuit board assembly and the dielectric layer, and the hole wall of the first via being spaced apart from the first metal layer; forming a second metal layer, the second metal layer covering the hole wall of the first via, the first metal layer, the second metal layer and the dielectric layer together forming a capacitor structure; and the intermediate structure and the second metal layer together forming a multilayer circuit board with the capacitor structure. The steps of the above method are relatively simple, and the capacitor structure does not need to be formed by pasting a patch, so the cost is relatively low. The multilayer circuit board formed by the above method has a coaxial capacitor structure, the capacitor structure occupies a relatively small surface area of the multilayer circuit board, and a capacitor structure with a relatively large capacity can be formed, which is beneficial to the thinning and miniaturization of the multilayer circuit board, and thus the performance of the multilayer circuit board with the capacitor structure is improved. Through the above method, a multilayer circuit board with a buried capacitor element can be formed, and the performance and reliability of the multilayer circuit board are improved, and thus the integration of the multilayer circuit board is improved.

[0034] The construction of the application and the other objects and advantages of the present application will become more apparent from the following description with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0036] Figure 1 The first flowchart of the manufacturing method of the multilayer circuit board provided by the embodiments of the present application;

[0037] Figure 2 The first cross-sectional structure schematic diagram of the multilayer circuit board provided by the embodiments of the present application;

[0038] Figure 3 The second cross-sectional structure schematic diagram of the multilayer circuit board provided by the embodiments of the present application;

[0039] Figure 4 The third cross-sectional structure schematic diagram of the multilayer circuit board provided by the embodiments of the present application;

[0040] Figure 5 The partial three-dimensional structure schematic diagram of the multilayer circuit board provided by the embodiments of the present application;

[0041] Figure 6 The partial cross-sectional structure schematic diagram of the multilayer circuit board provided by the embodiments of the present application;

[0042] Figure 7 The fourth cross-sectional structure schematic diagram of the multilayer circuit board provided by the embodiments of the present application;

[0043] Figure 8 The second flowchart of the manufacturing method of the multilayer circuit board provided by the embodiments of the present application;

[0044] Figure 9 The third flowchart of the manufacturing method of the multilayer circuit board provided by the embodiments of the present application;

[0045] Figure 10 The fourth cross-sectional structure schematic diagram of the multilayer circuit board provided by the embodiments of the present application;

[0046] Figure 11 The fifth cross-sectional structure schematic diagram of the multilayer circuit board provided by the embodiments of the present application;

[0047] Figure 12 The sixth cross-sectional structure schematic diagram of the multilayer circuit board provided by the embodiments of the present application;

[0048] Figure 13A seventh cross-sectional structure schematic diagram of a multilayer circuit board provided by an embodiment of the present application is shown in FIG. 7.

[0049] Figure 14 An eighth cross-sectional structure schematic diagram of a multilayer circuit board provided by an embodiment of the present application is shown in FIG. 8.

[0050] Figure 15 A fourth flow schematic diagram of a manufacturing method of a multilayer circuit board provided by an embodiment of the present application is shown in FIG. 4.

[0051] Figure 16 A ninth cross-sectional structure schematic diagram of a multilayer circuit board provided by an embodiment of the present application is shown in FIG. 9.

[0052] Figure 17 A tenth cross-sectional structure schematic diagram of a multilayer circuit board provided by an embodiment of the present application is shown in FIG. 10.

[0053] Figure 18 An eleventh cross-sectional structure schematic diagram of a multilayer circuit board provided by an embodiment of the present application is shown in FIG. 11.

[0054] Explanation of reference signs:

[0055] 10 - multilayer circuit board; 100 - intermediate structure; 101 - capacitor structure;

[0056] 110 - circuit board assembly; 111 - circuit board substrate; 112 - prepreg; 113 - fourth metal layer;

[0057] 120 - dielectric layer; 121 - outer dielectric layer; 122 - inner dielectric layer;

[0058] 130 - first metal layer; 140 - first via; 150 - second metal layer; 160 - third metal layer; 170 - second via.

[0059] The above drawings have shown the specific embodiments of the present application, which will be described in more detail hereinafter. These drawings and written descriptions are not intended to limit the scope of the concept of the present application by any means, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0060] In the related art, a surface mount capacitor is usually used on the surface of a PCB. The surface mount capacitor needs to occupy a large area on the PCB, which is not conducive to the miniaturization of the PCB. In addition, the buried capacitor circuit board in the related art usually includes a copper foil and a capacitor dielectric which are stacked. The copper foil and the capacitor dielectric need to be pressed multiple times during the manufacturing process of the multilayer circuit board, which is a complicated process and has a high processing cost. Moreover, the capacitor structure formed by this method has a large surface area on the multilayer circuit board and a small capacity, and the performance of the multilayer circuit board cannot meet the user's demand.

[0061] To solve the above technical problems, the embodiment of the present application provides a multilayer circuit board and a manufacturing method thereof. The manufacturing method comprises the following steps: providing an intermediate structure, the intermediate structure comprising a circuit board assembly, a dielectric layer and a first metal layer, the dielectric layer and the first metal layer being located in the circuit board assembly, and the dielectric layer being located on a side of the first metal layer away from the circuit board assembly; forming a first via, the first via penetrating the circuit board assembly and the dielectric layer, and the hole wall of the first via being spaced apart from the first metal layer; forming a second metal layer, the second metal layer covering the hole wall of the first via, the first metal layer, the second metal layer and the dielectric layer together forming a capacitor structure; and the intermediate structure and the second metal layer together forming a multilayer circuit board with the capacitor structure. The steps of the above method are relatively simple, and the capacitor structure does not need to be formed by pasting, so the cost is relatively low. The multilayer circuit board formed by the above method has a coaxial capacitor structure, the capacitor structure occupies a relatively small surface area of the multilayer circuit board, a capacitor structure with a large capacity can be formed, which is beneficial to the thinning and miniaturization of the multilayer circuit board, and thus the performance of the multilayer circuit board with the capacitor structure is improved. Through the above method, a multilayer circuit board with a buried capacitor element can be formed, and the performance and reliability of the multilayer circuit board are improved, and thus the integration of the multilayer circuit board is improved.

[0062] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the preferred embodiments of the present application. Identical or similar reference numerals in the drawings represent identical or similar structural elements or structural elements with identical or similar functions throughout. The described embodiments are part of the structural embodiments of the present application, rather than the whole structural embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0063] Referring to Figures 1-18 The first aspect, the present application provides a manufacturing method of a multilayer circuit board 10, comprising:

[0064] Referring to Figure 1 , Figure 2 , Figure 8 , Figure 9 and Figure 15 , S100, an intermediate structure is provided, the intermediate structure comprising a circuit board assembly, a dielectric layer and a first metal layer, the dielectric layer and the first metal layer being located in the circuit board assembly, and the dielectric layer being located on a side of the first metal layer away from the circuit board assembly.

[0065] It can be understood that the medium layer 120 can be an insulating layer in a capacitor, used for storing electric charge and increasing capacitance. The material of the medium layer 120 can be any material.

[0066] For example, the material of the medium layer 120 can be one or more of aluminum oxide (Al2O3), zirconium dioxide (ZrO2), polytetrafluoroethylene (PTFE), polyethylene, and polypropylene. The specific material of the medium layer 120 is not limited in the embodiments of the present application, and is not limited to the above examples.

[0067] It should be noted that the first metal layer 130 can be used for electrical connection. The material of the first metal layer 130 can be any material. For example, the material of the first metal layer 130 can be one or more of copper (Cu), silver (Ag), nickel (Ni), gold (Au), and aluminum (Al). The specific material of the first metal layer 130 is not limited in the embodiments of the present application, and is not limited to the above examples.

[0068] It can be understood that the material of the medium layer 120 and the first metal layer 130 can be selected according to actual conditions.

[0069] In some embodiments, the medium layer 120 and the first metal layer 130 in the circuit board assembly 110 can mean that the circuit board assembly 110 has a mounting hole, and the medium layer 120 and the first metal layer 130 are located in the mounting hole. The medium layer 120 is closer to the circuit board assembly 110 than the first metal layer 130, that is, the medium layer 120 can wrap the first metal layer 130.

[0070] It should be noted that the medium layer 120 and the first metal layer 130 can be arranged in sequence along the surface extension direction of the circuit board assembly 110, or can be arranged in sequence along the thickness direction of the circuit board assembly 110.

[0071] Hereinafter, the medium layer 120 and the first metal layer 130 are arranged in sequence along the surface extension direction of the circuit board assembly 110, that is, the medium layer 120 and the first metal layer 130 extend along the thickness direction of the circuit board assembly 110.

[0072] It can be understood that the end surface of the medium layer 120 and the end surface of the first metal layer 130 can extend to the outer surface of the circuit board assembly 110, or can be located inside the circuit board assembly 110.

[0073] Hereinafter, the end surface of the medium layer 120 and the end surface of the first metal layer 130 are located inside the circuit board assembly 110.

[0074] Referring to Figure 1 , Figure 3 , Figure 8 , Figure 9 and Figure 15 , S200, a first via hole is formed, the first via hole penetrating the circuit board assembly and the dielectric layer, and a hole wall of the first via hole is spaced apart from the first metal layer.

[0075] It can be understood that the axis of the first via hole 140 can extend along the thickness direction of the circuit board assembly 110, and the hole wall of the first via hole 140 is spaced apart from the first metal layer 130 by the dielectric layer 120.

[0076] It should be noted that when the end surface of the dielectric layer 120 and the end surface of the first metal layer 130 are located inside the circuit board assembly 110, the first via hole 140 needs to be first penetrated through the circuit board assembly 110 to penetrate the dielectric layer 120.

[0077] Referring to Figure 1 , Figures 4-6 , Figure 8 , Figure 9 and Figure 15 , S300, a second metal layer is formed, the second metal layer covers the hole wall of the first via hole, the first metal layer, the second metal layer and the dielectric layer together form a capacitor structure; the intermediate structure and the second metal layer together form a multi-layer circuit board with a capacitor structure.

[0078] It can be understood that the material of the second metal layer 150 can be the same as that of the first metal layer 130, or can be different. The material of the second metal layer 150 can refer to the material of the first metal layer 130, which will not be repeated here.

[0079] It should be noted that the hole wall of the first via hole 140 is spaced apart from the first metal layer 130 by the dielectric layer 120, and when the second metal layer 150 covers the hole wall of the first via hole 140, the second metal layer 150 is spaced apart from the first metal layer 130 by the dielectric layer 120, and the first metal layer 130, the second metal layer 150 and the dielectric layer 120 together form a capacitor structure 101, one of the first metal layer 130 and the second metal layer 150 is the positive electrode of the capacitor structure 101, and the other is the negative electrode of the capacitor structure 101.

[0080] Hereinafter, the first metal layer 130 is taken as the positive electrode of the capacitor structure 101, and the second metal layer 150 is taken as the negative electrode of the capacitor structure 101 as an example for description.

[0081] When the capacitor structure 101 is connected with the power supply, charges will flow from the power supply to the first metal layer 130, and the same amount of charges will flow out from the second metal layer 150. In this way, an electric field will be formed in the capacitor structure 101, and the charges are stored in the electric field. When the capacitor structure 101 is disconnected from the power supply, the charges stored in the capacitor structure 101 will begin to flow back to the circuit, releasing the stored energy.

[0082] It can be understood that the first metal layer 130, the second metal layer 150 and the dielectric layer 120 in the capacitor structure 101 are coaxially arranged, and the thickness of the dielectric layer 120 can be adjusted according to actual conditions.

[0083] In the multilayer circuit board 10, only the end surface of the second metal layer 150 is formed on the surface of the multilayer circuit board 10, and the capacitor structure 101 occupies a smaller surface area of the multilayer circuit board 10, which is beneficial to realize the lightness, thinness and miniaturization of the multilayer circuit board 10, thereby improving the performance of the multilayer circuit board 10 with the capacitor structure 101, and further improving the integration of the multilayer circuit board 10.

[0084] The preparation method of the multilayer circuit board 10 provided by the embodiment of the application can prepare the multilayer circuit board 10 described above, and the steps are relatively simple, the capacitor structure 101 can be formed without a patch, and the cost is relatively low.

[0085] Referring to Figures 2-7 As an optional embodiment, the intermediate structure 100 further includes a third metal layer 160 located on opposite sides of the dielectric layer 120.

[0086] It can be understood that the material of the third metal layer 160 can be the same as that of the first metal layer 130, or can be different. The material of the third metal layer 160 can refer to the material of the first metal layer 130, which will not be repeated here. That is, the materials of the first metal layer 130, the second metal layer 150 and the third metal layer 160 are the same.

[0087] Specifically, the third metal layer 160 is arranged spaced apart from the dielectric layer 120, and the extension direction of the third metal layer 160 intersects the extension direction of the second metal layer 150. That is, the third metal layer 160 is located on the outer side of the circuit board assembly 110, and the third metal layer 160 and the dielectric layer 120 are spaced apart by part of the circuit board assembly 110.

[0088] It can be understood that when the first through hole 140 is arranged to pass through the dielectric layer 120 and the circuit board assembly 110, it will also pass through the third metal layer 160 located on the outer side of the circuit board assembly 110. Therefore, when the outer wall of the first through hole 140 forms the second metal layer 150, the second metal layer 150 can be connected with the third metal layer 160.

[0089] It should be noted that when the medium layer 120 and the first metal layer 130 are both located inside the circuit board assembly 110, the number of the third metal layer 160 can be two, and the two metal layers are located on opposite sides of the circuit board assembly 110 along the thickness direction.

[0090] Among them, the two third metal layers 160 can be used to connect the positive and negative poles of the power supply, respectively.

[0091] By introducing the intermediate structure 100 for forming the capacitor structure 101 in the manufacturing process of the multilayer circuit board 10, the capacitor structure 101 can be formed without a patch, which can reduce the cost. The extension direction of the third metal layer 160 intersects the extension direction of the first metal layer 130, so that the second metal layer 150 can be connected with the third metal layer 160, which can enhance the stability and reliability of the capacitor structure 101, improve the performance and integration of the multilayer circuit board 10, and reduce the manufacturing cost, so as to facilitate the miniaturization and thinning of the multilayer circuit board.

[0092] Referring to Figure 7 As an optional embodiment, the number of capacitor structures 101 is multiple.

[0093] It can be understood that the number of capacitor structures 101 can be two, three, four, five, six, seven, eight, etc. The specific number of capacitor structures 101 is not limited in the embodiment of the application, and is not limited to the above examples.

[0094] The number of capacitor structures 101 is two as an example.

[0095] Referring to Figure 7 In some embodiments, along the surface extension direction of the third metal layer 160, the multiple capacitor structures 101 are arranged at intervals, and the adjacent capacitor structures 101 are connected by the third metal layer 160.

[0096] It can be understood that the second metal layer 150 of the capacitor structure 101 is connected with the third metal layer 160. When there are multiple capacitor structures 101, adjacent capacitor structures 101 can be connected by the third metal layer 160 located outside the circuit board assembly 110.

[0097] It should be noted that the two adjacent capacitor structures 101 can be connected by two oppositely arranged third metal layers 160 to realize the electrical connection of the two capacitor structures 101.

[0098] In some embodiments, along the thickness direction of the circuit board assembly 110, the multiple capacitor structures 101 are arranged at intervals, and the adjacent capacitor structures 101 are connected by the third metal layer 160.

[0099] It can be understood that the second metal layer 150 of the capacitor structure 101 is connected with the third metal layer 160. When there are multiple capacitor structures 101, adjacent capacitor structures 101 can be connected through the third metal layer 160 located outside the circuit board assembly 110.

[0100] It should be noted that two adjacent capacitor structures 101 can be connected through two oppositely arranged third metal layers 160 to realize the electrical connection of the two capacitor structures 101.

[0101] By arranging multiple capacitor structures 101 in a specific direction on the surface of the third metal layer 160 and spacing them, the space can be effectively utilized, the layout between the capacitor structures 101 is relatively compact, adjacent capacitor structures 101 are connected through the third metal layer 160, the structural stability and reliability of the multilayer circuit board 10 can be enhanced, the risk of interference or damage caused by external environmental changes can be reduced, and the electrical connection can be facilitated to improve the performance of the multilayer circuit board 10.

[0102] As an optional embodiment, the intermediate structure 100 includes multiple dielectric layers 120 and multiple first metal layers 130, and the multiple dielectric layers 120 are sequentially and spaced apart through the multiple first metal layers 130.

[0103] It can be understood that the number of dielectric layers 120 can be two, three, four, five, six, seven, eight, etc., and the number of first metal layers 130 can be two, three, four, five, six, seven, eight, etc. The specific number of dielectric layers 120 and first metal layers 130 is not limited by the present application, nor is it limited to the above examples.

[0104] It should be noted that the multiple dielectric layers 120 are sequentially and spaced apart through the multiple first metal layers 130, which means that the multiple dielectric layers 120 and the multiple first metal layers 130 are alternately arranged, and one dielectric layer 120 is located between two adjacent first metal layers 130, thereby forming a capacitor structure 101 with multiple dielectric layers 120.

[0105] Through the above arrangement, through the multi-layer arrangement of the multiple dielectric layers 120 and the multiple first metal layers 130, the level of the capacitor structure 101 can be increased, thereby improving the capacity of the capacitor structure 101 and meeting the performance requirements; the electric field distribution can be optimized to reduce the electric field concentration phenomenon and improve the stability and performance of the capacitor structure 101; the structural stability of the capacitor structure 101 can be enhanced to reduce the influence of external interference on the capacitor structure 101.

[0106] Referring to Figures 8-15 As an optional embodiment, the intermediate structure 100 includes:

[0107] S110, providing a circuit board assembly;

[0108] S120, forming a second through hole, an axis of the second through hole extending along a thickness direction of the circuit board assembly;

[0109] S130, forming a first metal layer, the first metal layer covering a hole wall of the second through hole;

[0110] It can be understood that the material of the first metal layer 130 can be the same as or different from the material of the first metal layer 130. The material of the first metal layer 130 can refer to the material of the first metal layer 130, which will not be repeated here.

[0111] S140, forming a dielectric layer, the dielectric layer being located in the second through hole, and the dielectric layer being located on a side of the first metal layer away from the circuit board assembly;

[0112] S150, sequentially stacking a prepreg and a fourth metal layer on a side of the dielectric layer away from the circuit board assembly, the dielectric layer, the first metal layer, the circuit board assembly, the prepreg and the fourth metal layer collectively forming an intermediate structure.

[0113] It can be understood that when the first through hole 140 is formed, the first through hole 140 can be coaxially arranged with the second through hole 170, so as to form a dielectric layer 120 with uniform thickness.

[0114] By forming the first metal layer 130 on the hole wall of the second through hole 170, the stability and reliability of the intermediate structure 100 can be enhanced, so as to effectively fix the dielectric layer 120 and the metal layer, and improve the durability and performance of the overall structure. At the same time, the coaxial arrangement of the first through hole 140 and the second through hole 170 can make the dielectric layer 120 have more uniform thickness, and improve the stability and performance of the structure.

[0115] Referring to FIG. 1, Figure 9 As an optional embodiment, when the intermediate structure 100 includes a plurality of dielectric layers 120 and a plurality of first metal layers 130,

[0116] After the dielectric layer 120 is formed, it further includes:

[0117] S145, repeatedly forming a second through hole, a first metal layer and a dielectric layer on the dielectric layer.

[0118] It can be understood that the repeated formation can be to continue to form a second through hole 170 on the dielectric layer 120, i.e. an external dielectric layer 121, and cover a first metal layer 130 on the hole wall of the second through hole 170, and then form a new dielectric layer 120 in the second through hole 170, the new dielectric layer 120 being an internal dielectric layer 122.

[0119] It should be noted that the inner dielectric layer 122 and the outer dielectric layer 121 can be alternately arranged by repeatedly forming the first metal layer 130, thereby forming the capacitor structure 101 with multiple layers of dielectric layers 120.

[0120] Through the above arrangement, the level of the capacitor structure 101 can be increased, thereby improving the capacity of the capacitor structure 101 to meet performance requirements; the electric field distribution can be optimized to reduce the electric field concentration phenomenon and improve the stability and performance of the capacitor structure 101; the structural stability of the capacitor structure 101 can be enhanced to reduce the influence of external interference on the capacitor structure 101.

[0121] As an optional implementation, the materials of the multiple dielectric layers 120 can be the same or different.

[0122] In some embodiments, when the multilayer circuit board 10 includes multiple capacitor structures 101, the materials of the dielectric layers 120 used by different capacitor structures 101 can be the same or different.

[0123] In some embodiments, when the capacitor structure 101 includes multiple layers of dielectric layers 120, the materials of the dielectric layers 120 at different positions can be the same or different.

[0124] For example, assume that a multilayer circuit board 10 includes two capacitor structures 101, and each capacitor structure 101 contains two dielectric layers 120. In the first capacitor structure 101, the materials of the dielectric layer 1 and the dielectric layer 2 are the same, both being polyimide (PI) material. In the second capacitor structure 101, the materials of the dielectric layer 3 and the dielectric layer 4 are different, the dielectric layer 3 being polytetrafluoroethylene (PTFE) material and the dielectric layer 4 being glass fiber reinforced epoxy resin (FR-4) material.

[0125] When the materials of the multiple dielectric layers 120 are the same, consistent electrical performance can be provided, reducing instability caused by material differences, and facilitating improvement of the reliability and performance consistency of the multilayer circuit board 10.

[0126] When the materials of the multiple dielectric layers 120 are different, the most suitable material can be selected according to specific design requirements to achieve better electrical and mechanical performance. For example, PTFE material has a lower dielectric constant and loss, which is suitable for high-frequency applications; and FR-4 material has better mechanical strength and heat resistance, which is suitable for general applications. The electrical performance, mechanical performance, and cost factors can be balanced according to specific design requirements, thereby achieving better overall performance and reliability.

[0127] Referring to Figures 15-18 As an optional implementation, the circuit board assembly 110 is provided, as shown in

[0128] S111. Provide a circuit board substrate covered with a copper layer.

[0129] S112, patterning the circuit board substrate to form a circuit pattern.

[0130] It is understandable that a circuit pattern is obtained on the circuit board substrate 111 through steps such as attaching a photosensitive film, exposing, developing, etching, and stripping according to the designed pattern.

[0131] S113 , forming a prepreg and a fourth metal layer in sequence on a side of the circuit pattern away from the circuit board substrate.

[0132] It is understood that the material of the fourth metal layer 113 can be the same as or different from the material of the first metal layer 130. The material of the fourth metal layer 113 can refer to the material of the first metal layer 130 and will not be described in detail here.

[0133] It should be noted that the prepreg 112 can be made of any material. For example, the material of the prepreg 112 may include, but is not limited to, glass fiber reinforced epoxy resin (FR-4), polyimide (PI), polyetheretherketone (PEEK), etc. The present embodiment of the application does not limit the specific material of the prepreg 112, nor is it limited to the above examples.

[0134] S114, heating the prepreg, and filling the prepreg with circuit patterns to form a circuit board assembly.

[0135] It is understood that the purpose of heating is to soften or flow the prepreg 112 so that the circuit pattern can be filled in. The heating temperature and time need to be controlled according to the material and process requirements of the prepreg 112 to ensure that the prepreg 112 can achieve appropriate fluidity and adhesion.

[0136] Reference Figure 8 and Figure 9 As shown, it should be noted that after forming the dielectric layer 120 and before forming the second metal layer 150, the following steps are further included:

[0137] S150 , stacking a prepreg and a fourth metal layer in sequence on a side of the dielectric layer away from the circuit board assembly. The dielectric layer, the first metal layer, the circuit board assembly, the prepreg and the fourth metal layer together form an intermediate structure.

[0138] Reference Figures 2-4 、 Figures 10-15 As shown, as an optional implementation, the first metal layer 130 is connected to the fourth metal layer 113 .

[0139] Specifically, the extension direction of the fourth metal layer 113 intersects with the extension direction of the first metal layer 130 . That is, the third metal layer 160 is located outside the circuit board substrate 111 .

[0140] It can be understood that the second through hole 170 will also pass through the fourth metal layer 113 located outside the circuit board assembly 110 when passing through the circuit board substrate 111. Therefore, when the outer wall of the second through hole 170 forms the first metal layer 130, the first metal layer 130 can be connected with the fourth metal layer 113.

[0141] It should be noted that the opposite sides of the circuit board substrate 111 can be covered with copper layers.

[0142] Among them, the two fourth metal layers 113 can be used to connect the positive and negative poles of the power supply, respectively.

[0143] Through the above arrangement, the stability and reliability of the capacitor structure 101 can be enhanced, the contact resistance and inductance in the capacitor structure 101 can be reduced, and the performance of the capacitor structure 101 can be improved. In addition, the conductivity and response speed of the capacitor structure 101 can be improved, thereby improving the performance of the overall circuit board. Secondly, the structure of the multilayer circuit board 10 can be simplified, the number of elements and connection points in the multilayer circuit board 10 can be reduced, and the manufacturing cost and maintenance difficulty can be reduced.

[0144] Referring to Figures 4-6 It is shown that in the second aspect, the embodiments of the present application also provide a multilayer circuit board 10 prepared by the manufacturing method of the multilayer circuit board 10.

[0145] The multilayer circuit board 10 provided by the present application has a coaxial structure, and the capacitor structure 101 occupies a smaller surface area of the multilayer circuit board 10, which can form a capacitor structure 101 with a larger capacity, which is conducive to realizing the lightness, thinness and miniaturization of the multilayer circuit board 10, and thus improving the performance of the multilayer circuit board 10 with the capacitor structure 101. Through the above method, a multilayer circuit board 10 with a buried capacitor element can be formed, which can improve the performance and reliability of the multilayer circuit board 10, and thus improve the integration of the multilayer circuit board 10.

[0146] In the description of the embodiments of the present application, it should be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be a fixed connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between two element structures or an interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0147] The terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like, indicate an orientation or positional relationship based on the orientation or positional relationship as shown in the drawings, and are used only to facilitate description of the application and are not intended to convey specific orientations or positional relationships of the apparatus or elements thereof, and thus should not be construed to limit the application. In the description of the application, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0148] The terms "first", "second", "third", "first", etc. in the specification and claims of the application and above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0149] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit it; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to the structure or whole structure technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A method for manufacturing a multi-layer circuit board, characterized in that: include: Providing an intermediate structure, the intermediate structure comprising a circuit board assembly, a dielectric layer, and a first metal layer, wherein the dielectric layer and the first metal layer are located within the circuit board assembly, and the dielectric layer is located on a side of the first metal layer away from the circuit board assembly; forming a first through hole, wherein the first through hole penetrates the circuit board assembly and the dielectric layer, and a hole wall of the first through hole is spaced apart from the first metal layer; A second metal layer is formed, the second metal layer covers the hole wall of the first through hole, the first metal layer, the second metal layer and the dielectric layer together form a capacitor structure; the intermediate structure and the second metal layer together form a multilayer circuit board having the capacitor structure.

2. The method for manufacturing a multi-layer circuit board according to claim 1, wherein: The intermediate structure further includes a third metal layer located on opposite sides of the dielectric layer, the third metal layer is spaced apart from the dielectric layer, and an extension direction of the third metal layer intersects with an extension direction of the second metal layer; The second metal layer is connected to the third metal layer.

3. The method for manufacturing a multi-layer circuit board according to claim 2, wherein: There are multiple capacitor structures; Along the surface extension direction of the third metal layer, the plurality of capacitor structures are arranged at intervals, and adjacent capacitor structures are connected through the third metal layer; And / or, along the thickness direction of the circuit board assembly, the plurality of capacitor structures are arranged at intervals, and adjacent capacitor structures are connected via the third metal layer.

4. The method for manufacturing a multi-layer circuit board according to claim 1, wherein: The intermediate structure includes a plurality of dielectric layers and a plurality of first metal layers, and the plurality of dielectric layers are sequentially spaced apart by the plurality of first metal layers.

5. The method for manufacturing a multi-layer circuit board according to any one of claims 1 to 4, characterized in that: Provide intermediate structures including: Providing circuit board assemblies; forming a second through hole, wherein the axis of the second through hole extends along the thickness direction of the circuit board assembly; forming the first metal layer, wherein the first metal layer covers the hole wall of the second through hole; forming the dielectric layer, wherein the dielectric layer is located in the second through hole and is located on a side of the first metal layer away from the circuit board assembly; A prepreg and a third metal layer are sequentially stacked on a side of the dielectric layer away from the circuit board assembly. The dielectric layer, the first metal layer, the circuit board assembly, the prepreg and the third metal layer together form the intermediate structure.

6. The method for manufacturing a multi-layer circuit board according to claim 5, wherein: When the intermediate structure includes a plurality of dielectric layers and a plurality of first metal layers, After forming the dielectric layer, the following steps are also included: The second through hole, the first metal layer and the dielectric layer are repeatedly formed on the dielectric layer.

7. The method for manufacturing a multi-layer circuit board according to claim 6, wherein: The multiple dielectric layers are made of the same or different materials.

8. The method for manufacturing a multi-layer circuit board according to claim 5, wherein: The circuit board components provided include: providing a circuit board substrate covered with a copper layer; Graphically processing the circuit board substrate to form a circuit pattern; forming the prepreg and the fourth metal layer in sequence on a side of the circuit pattern away from the circuit board substrate; The prepreg is heated, and the prepreg fills the circuit pattern to form the circuit board assembly.

9. The method for manufacturing a multi-layer circuit board according to claim 8, wherein: The first metal layer is connected to the fourth metal layer.

10. A multi-layer circuit board, characterized in that: The multilayer circuit board is prepared by the method for manufacturing the multilayer circuit board according to any one of claims 1 to 9.

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