WO2021203328A1

WO2021203328A1 - Embedded circuit board and fabrication method therefor

Info

Publication number: WO2021203328A1
Application number: PCT/CN2020/083827
Authority: WO
Inventors: 王蓓蕾; 郭伟静; 谢占昊
Original assignee: 深南电路股份有限公司
Priority date: 2020-04-08
Filing date: 2020-04-08
Publication date: 2021-10-14

Abstract

Disclosed are an embedded circuit board (1000) and a fabrication method therefor. The embedded circuit board (1000) comprises: a circuit board main body (1100); and a magnetic core (1200) and a metal substrate (1300) that are embedded in the circuit board main body (1100). The embedded circuit board (1000) not only can reduce the size of the circuit board, but can also improve the heat dissipation performance of the circuit board.

Description

Embedded circuit board and preparation method thereof

【Technical Field】

This application relates to the technical field of circuit boards, in particular to an embedded circuit board and a preparation method thereof.

【Background technique】

With the increase in the integration of electronic products, the requirements for miniaturization of power modules are becoming higher and higher, which makes it necessary to reduce the layout space of the devices. As the core components of the power modules, magnetic devices occupy a lot of space on the printed circuit board. Become a key factor restricting the development of miniaturization of power modules.

At present, a design method of embedding magnetic devices in a circuit board has emerged in response to the above situation, but the inventor of the present application found that the current heat dissipation performance of the circuit board with embedded magnetic devices needs to be improved.

[Summary of the invention]

The main technical problem solved by this application is to provide an embedded circuit board and a preparation method thereof, which can reduce the volume of the circuit board and improve the heat dissipation performance of the circuit board.

In order to solve the above technical problems, a technical solution adopted in this application is to provide an embedded circuit board, including: a circuit board main body; a magnetic core and a metal base, all embedded in the circuit board main body.

In order to solve the above technical problems, another technical solution adopted by the present application is to provide a method for preparing an embedded circuit board. The preparation method includes: preparing a main body of a first sub-circuit board; A first accommodating groove is formed on the main body, and a magnetic core is placed in the first accommodating groove; a second sub-circuit board main body is formed on the side of the first sub-circuit board main body that exposes the magnetic core to cover The magnetic core; forming a second accommodating groove, placing the metal base in the second accommodating groove.

In order to solve the above technical problems, another technical solution adopted in this application is to provide a method for preparing an embedded circuit board, the preparation method includes: preparing a first sub-circuit board body; A first accommodating groove is formed on the main body, and the metal base is placed in the first accommodating groove; a second accommodating groove is formed on the main body of the first sub-circuit board, and the magnetic core is placed in the second accommodating groove. Placed in the groove; a second sub-circuit board body is formed on the side of the first sub-circuit board body that exposes the magnetic core to cover the magnetic core.

The beneficial effect of the present application is: in the embedded circuit board of the present application, the magnetic core and the metal base are embedded in the main body of the circuit board at the same time, which can reduce the volume of the circuit board and improve the heat dissipation performance of the circuit board. .

【Explanation of the drawings】

In order to more clearly describe the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings that need to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. in:

FIG. 1 is a schematic cross-sectional structure diagram of an embodiment of an embedded circuit board according to the present application;

FIG. 2 is a schematic top view of the embedded circuit board of FIG. 1;

3 is a schematic cross-sectional structure diagram of the embedded circuit board of FIG. 1 in an application scenario;

4 is a schematic cross-sectional structure diagram of the embedded circuit board of FIG. 1 in another application scenario;

5 is a schematic cross-sectional structure diagram of the embedded circuit board of FIG. 1 in another application scenario;

6 is a schematic cross-sectional structure diagram of another embodiment of an embedded circuit board according to the present application;

FIG. 7 is a schematic flowchart of an embodiment of a method for manufacturing an embedded circuit board according to the present application;

FIG. 8 is a preparation process diagram corresponding to the preparation method of FIG. 7;

Fig. 9 is a partial preparation process diagram of the preparation method of Fig. 7 in another application scenario;

FIG. 10 is a schematic flowchart of another embodiment of the method for manufacturing an embedded circuit board according to the present application;

FIG. 11 is a preparation process diagram corresponding to the preparation method of FIG. 10;

Fig. 12 is a partial preparation process diagram of the preparation method of Fig. 10 in another application scenario.

【Detailed ways】

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

1 to FIG. 2, FIG. 1 is a schematic cross-sectional structure diagram of an embodiment of the embedded circuit board of the present application, and FIG. 2 is a schematic top view of the embedded circuit board of FIG. 1. The embedded circuit board 1000 includes a circuit board main body 1100, a magnetic core 1200 and a metal base 1300.

The circuit board main body 1100 plays a main supporting role in the entire embedded circuit board 1000, and the magnetic core 1200 and the metal base 1300 are embedded in the circuit board main body 1100 at the same time. The material of the magnetic core 1200 may be manganese-zinc-iron, nickel-zinc-iron or amorphous magnetic material, and the material of the metal base 1300 may be copper, aluminum or an alloy including copper and aluminum, or other conductive materials.

Specifically, embedding the magnetic core 1200 in the circuit board main body 1100 can reduce the volume of the embedded circuit board 1000 compared to being arranged on the surface of the circuit board main body 1100. At the same time, since the metal base 1300 is made of conductive material, It can transfer heat and transfer the heat from the higher temperature area to the lower temperature area, thereby improving the heat dissipation performance of the embedded circuit board 1000. That is to say, in this embodiment, the magnetic core 1200 and the metal base 1300 are embedded at the same time. In the circuit board main body 1100, the volume of the embedded circuit board 1000 can be reduced, and the heat dissipation performance of the embedded circuit board 1000 can also be improved.

Among them, in an application scenario, the metal base 1300 is provided with electronic components (not shown), such as chips, etc., and the metal base 1300 is used to dissipate the electronic components thereon.

Continuing to refer to FIG. 1, in this embodiment, signal transmission layers 1110 are provided on opposite sides of the circuit board main body 1100.

The signal transmission layer 1110 is made of conductive materials, such as copper, aluminum, etc., for signal transmission. The metal base 1300 is electrically connected to the signal transmission layers 1110 located on opposite sides of the circuit board main body 1100 to realize signal transmission between the two signal transmission layers 1110. That is to say, at this time, the metal base 1300 can also realize the function of heat dissipation. Current-carrying function.

It should be noted that in other embodiments, the circuit board main body 1100 may further include a signal transmission layer 1110 disposed inside. That is, the embedded circuit board 1000 is a multilayer board. In this case, any two layers of signal transmission The layers 1110 may all be provided with a metal base 1300 that is electrically connected to each other, or, in other embodiments, the circuit board body 1100 is provided with a signal transmission layer 1110 on only one side surface and inside, and the metal base 1300 is electrically connected to the circuit board. The signal transmission layer 1110 on the surface of the main body 1100 and the signal transmission layer 1110 located inside the circuit board main body 1100, in a word, the number of layers and specific positions of the signal transmission layer 1110 are not limited in this application.

At the same time, in this embodiment, the thickness of the magnetic core 1200 is less than the thickness of the metal base 1300, and the cross section of the magnetic core 1200 can be circular, racetrack, square ring, etc., and the metal base 1300 has a cross-section along its thickness. Rectangular or T-shaped, there is no restriction here.

Continuing to refer to Figures 1 and 2, in an application scenario, the number of metal bases 1300 is more than two, such as 2, 4, or more. In Figures 1 and 2, the number of metal bases 1300 is two. A schematic description. At the same time, two or more metal bases 1300 include a first metal base 1310 and a second metal base 1320. The first metal base 1310 penetrates the magnetic core 1200, and the second metal base 1320 is located at the periphery of the magnetic core 1200.

The signal transmission layer 1110 includes a wire pattern 1111. The wire pattern 1111 is provided across the first metal base 1310 and the second metal base 1320 to form a coil loop capable of transmitting current around the magnetic core 1200, that is, in this application In the scene, the first metal base 1310 and the second metal base 1320 cooperate with each other to form a coil loop that transmits current around the magnetic core 1200.

It should be noted that when the number of metal bases 1300 is more than two, the remaining metal bases 1300 except for the first metal base 1310 and the second metal base 1320 can be distributed on the circuit board main body 1100. Any wiring that needs to achieve a large current carrying capacity There are no restrictions on the location or heat dissipation location.

Continuing to refer to Figures 1 and 2, in this application scenario, the circuit board main body 1100 is also provided with a first via hole 1400, and a conductive material is provided in the first via hole 1400 for realizing the connection on both sides of the circuit board main body 1100 The electrical connection of the wire pattern 1111, that is, the wire pattern 1111 does not only rely on the metal base 1300 to achieve electrical connection. The conductive material may be materials such as copper, aluminum, etc. The conductive material is disposed on the inner wall of the first via hole 1400 or fills the first via hole 1400 (as shown in FIG. 1).

Wherein, the number of the first via 1400 is at least one, such as 1, 2, 5, etc., and the at least one first via 1400 can be distributed at any position of the circuit board main body 1100, which is not limited here. .

Wherein, when the number of the first vias 1400 is multiple, the conductive pattern 1111 is bridged between at least two of the first vias 1400 for signal transmission.

Refer to FIG. 3, which is a schematic cross-sectional structure diagram of the embedded circuit board of FIG. 1 in an application scenario. The difference from the application scenario of FIG. 1 is that in this embodiment, the number of metal bases 1300 is more than one, for example, one, two or more. In FIG. 3, the number of the metal base 1300 is taken as one for schematic illustration. The one or more metal bases 1300 include a first metal base 1310, and the first metal base 1310 penetrates the magnetic core 1200.

At the same time, the circuit board main body 1100 is provided with a second via hole 1500 located at the periphery of the magnetic core 1200, the signal transmission layer 1110 includes a wire pattern 1111, and a wire pattern 1111 is bridged between the first metal base 1310 and the second via hole 1500 , The second via hole 1500 is provided with a conductive material for electrically connecting the wire patterns 1111 on the two signal transmission layers 1110 to form a coil loop capable of transmitting current around the magnetic core 1200, that is, the same as the above application scenarios The difference is that in this application scenario, the first metal base 1310 and the second through hole 1500 cooperate with each other to form a coil loop that transmits current around the magnetic core 1200.

The structure of the second via hole 1500 is similar to the structure of the first via hole 1400, which can be referred to the foregoing embodiment. At the same time, similar to the above application scenario, the metal base 1300 other than the first metal base 1310 can also be embedded in any position of the circuit board main body 1100, which is not limited here.

Refer to FIG. 4, which is a schematic cross-sectional structure diagram of the embedded circuit board of FIG. 1 in another application scenario. Similar to the application scenario of FIG. 3, in this application scenario, the number of metal bases 1300 is also more than one, for example, one, two or more. However, the difference from the structure in FIG. 3 is that the first metal base 1310 is located on the periphery of the magnetic core 1200, and the second through hole 1500 penetrates the magnetic core 1200. At this time, the mutual connection between the first metal base 1310 and the second through hole 1500 is used. Cooperating to form a coil loop that transmits current around the magnetic core 1200, that is, a wire pattern 1111 is also bridged between the first metal base 1310 and the second via hole 1500, and a conductive material is also provided in the second via hole 1500.

In the above application scenarios, the coil circuits that transmit current around the magnetic core 1200 all use the metal base 1300. However, in other application scenarios, the metal base 1300 may not be used to form a coil circuit that transmits current around the magnetic core 1200, for example, The through holes (not shown) provided inside and outside the magnetic core 1200 form a current-transmitting coil loop. Specifically, a conductive pattern 1111 is connected across the through holes provided inside and outside the magnetic core 1200, and Conductive materials are arranged in the through holes, so that a coil loop that transmits current around the magnetic core 1200 is formed through the mutual cooperation between the through holes.

At the same time, in an application scenario, as shown in FIG. 5, the circuit board main body 1100 includes a core board 1120 and a prepreg 1130 bonding adjacent core boards 1120. The number of the core board 1120 and the prepreg 1130 is not limited. At this time, the signal transmission The layer 1110 is a conductive layer provided on the surface of the core board 1120. Of course, in other application scenarios, the signal transmission layer 1110 may not be a conductive layer on the surface of the core board 1120, but a conductive layer bonded to the dielectric material layer through an adhesive layer. In this application, the structure of the circuit board main body 1100 is not specifically limited.

Refer to FIG. 6, which is a schematic cross-sectional structure diagram of another embodiment of an embedded circuit board of the present application. In this embodiment, the embedded circuit board 2000 includes two or more circuit board main bodies 2100, for example, two, three or more circuit board main bodies 2100, two or more circuit board main bodies 2100 are stacked, and each circuit board main body 2100 A magnetic core 2110 and a metal base 2120 are embedded in them.

Wherein, two adjacent circuit board main bodies 2100 are bonded by an adhesive layer 2200, and at the same time, the material of the adhesive layer 2200 may be a prepreg or epoxy resin.

In short, the application does not limit the number of layers of the circuit board main body 2100.

Refer to FIG. 7, which is a schematic flowchart of an embodiment of a method for manufacturing an embedded circuit board according to the present application. With reference to Figure 8, the preparation method includes:

S110: Prepare the first sub-circuit board main body 6100.

In an application scenario, the core board 6101 and the prepreg 6102 are stacked and arranged at intervals to form the first sub-circuit board main body 6100. In other application scenarios, the structure of the first sub-circuit board main body 6100 may be other, which is not limited here.

S120: forming a first accommodating groove 6110 on the first sub-circuit board main body 6100, and placing the magnetic core 6200 in the first accommodating groove 6110.

The size of the first accommodating groove 6110 is slightly larger than the size of the magnetic core 6200 or is equivalent to the size of the magnetic core 6200.

S130: A second sub-circuit board main body 6300 is formed on the side of the first sub-circuit board main body 6100 where the magnetic core 6200 is exposed to cover the magnetic core 6200.

In an application scenario, the structure of the second sub-circuit board main body 6300 is similar to the structure of the first sub-circuit board main body 6100. Specifically, the board prepreg 6102 is first placed on the side of the first sub-circuit board main body 6100 where the magnetic core 6200 is exposed. Then the core board 6101 is placed, and the process is repeated, wherein the number of layers of the core board 6101 and the prepreg 6102 in the second sub-circuit board main body 6300 is determined according to the specific circumstances in different application scenarios.

It is understandable that if the first accommodating groove 6110 is a through groove, the magnetic core 6200 is exposed on both sides of the first sub-circuit board main body 6100, so the second sub-circuit board main body 6300 is formed by a double-sided build-up method. The first accommodating groove 6110 is not a through groove. Only one side of the first sub-circuit board main body 6100 exposes the magnetic core 6200, so the second sub-circuit board main body 6300 is formed by a single-sided build-up method.

S140: forming a second accommodating groove 6120, and placing the metal base 6400 in the second accommodating groove 6120.

The size of the second accommodating groove 6120 is slightly larger than the size of the metal base 6400, or is equivalent to the size of the metal base 6400.

It can be seen from the above content that in this embodiment, the magnetic core 6200 is buried first, and then the metal base 6400 is buried.

In an application scenario, a signal transmission layer 6130 is formed on the side of the second sub-circuit board main body 6300 away from the first sub-circuit board main body 6100. At this time, in order to allow the metal base 6400 to play a current-carrying role, the metal base 6400 and the signal transmission layer 6130 may be electrically connected. Specifically, referring to FIG. 9, the preparation method further includes:

A conductive layer 6500 covering the metal base 6400 is formed on the side of the second sub-circuit board 6300 that exposes the metal base 6400, and the conductive layer 6500 is electrically connected to the signal transmission layer 6130 on the same side of the second sub-circuit board 6300, so that the metal base 6400 and The signal transmission layer 6130 is electrically connected, and then the signal transmission layer 6130 and the conductive layer 6500 are patterned to form a conductive pattern (not shown).

Wherein, the embedded circuit board prepared by the manufacturing method in this embodiment has the same or similar structure as the embedded circuit board in any one of the above embodiments, and the specific structure can refer to the above embodiment, which will not be repeated here.

Refer to FIG. 10, which is a schematic flowchart of another embodiment of an embedded circuit board according to the present application. The difference from the above-mentioned embodiment is that in this embodiment, the metal base is buried first, and then the magnetic core is buried. Specifically, with reference to FIG. 11, the preparation method includes:

S210: Prepare the first sub-circuit board main body 8100.

The first sub-circuit board main body 8100 has the same structure as the first sub-circuit board main body 6100 in the foregoing embodiment, and will not be repeated here.

S220: forming a first accommodating groove 8110 on the first sub-circuit board main body 8100, and placing the metal base 8200 in the first accommodating groove 8110.

In an application scenario, the thickness of the metal base 8200 is greater than the thickness of the first sub-circuit board main body 8100. At this time, step S220 specifically includes: protruding the first end 8210 of the metal base 8200 from the first sub-circuit board main body 8100. On the surface 8101, the second end 8220 of the metal base 8200 is arranged in the first sub-circuit board main body 8100. Of course, in other application scenarios, both ends of the metal base 8200 can also protrude from the surface of the first sub-circuit board main body 8100.

S230: A second accommodating groove 8120 is formed on the first sub-circuit board main body 8100, and the magnetic core 8300 is placed in the second accommodating groove 8120.

In an application scenario, when the magnetic core 8300 is required to surround the periphery of the metal base 8200, a second accommodating groove 8120 is formed in the first accommodating groove 8110, and when the first end 8210 of the metal base 8200 protrudes first When the first surface 8101 and the second end 8220 of a sub-circuit board main body 8100 are disposed in the first sub-circuit board main body 8100, the notch of the second accommodating groove 8120 is specifically disposed in the first sub-circuit board main body 8100. On surface 8101.

Optionally, in a specific application scenario, according to the size of the metal base 8200 and the magnetic core 8300, in the process of forming the second accommodating groove 8120, the metal base 8200 is milled, and then the cross section of the metal base 8200 in the thickness direction It is T-shaped. Optionally, in another specific application scenario, in the process of forming the second accommodating groove 8120, the metal base 8200 is not milled.

S240: A second sub-circuit board main body 8400 is formed on the side of the first sub-circuit board main body 8100 where the magnetic core 8300 is exposed to cover the magnetic core 8300.

In an application scenario, a second sub-circuit board main body 8400 is formed on the first surface 8101 of the first sub-circuit board main body 8100 to cover the magnetic core 8300, and the second sub-circuit board main body 8400 is provided with a through hole corresponding to the metal base 8200 8401, so that the first end 8210 of the metal base 8200 is disposed in the second sub-circuit board main body 8400 and the second sub-circuit board main body 8400 exposes the first end 8210 of the metal base 8200.

In the above content, it is described that one end of the metal base 8200 protrudes from the side of the first sub-circuit board main body 8100. In this case, the second sub-circuit board main body 8400 is formed by a single-sided build-up method.

It is understandable that in other application scenarios, when both ends of the metal base 8200 protrude from the surface of the first sub-circuit board main body 8100 at the same time, the second sub-circuit board main body 8400 needs to be formed by a double-sided build-up method, which is specifically prepared The process will not be repeated here.

In an application scenario, a signal transmission layer 8410 is formed on the side of the second sub-circuit board main body 8400 away from the first sub-circuit board main body 8100. At this time, in order to allow the metal base 8200 to play a current-carrying role, the metal base 8200 and the signal transmission layer 8410 may be electrically connected. Specifically, referring to FIG. 12, the preparation method further includes:

A conductive layer 8500 covering the metal base 8200 is formed on the side of the second sub-circuit board 8400 where the metal base 8200 is exposed, and the conductive layer 8500 is electrically connected to the signal transmission layer 8410 on the same side of the second sub-circuit board 8400, so that the metal base 8200 and The signal transmission layer 8410 is electrically connected, and then the signal transmission layer 8410 and the conductive layer 8500 are patterned to form a conductive pattern (not shown).

Similarly, when the first sub-circuit board 8100 also includes the signal transmission layer 8410, the same preparation method can also be used to electrically connect the metal base 8200 and the signal transmission layer 8410 in the first sub-circuit board 8100 to form a wire pattern. , The specific preparation process will not be repeated here.

Wherein, the buried circuit board prepared by the preparation method in this embodiment has the same structure as the buried circuit board in any of the above embodiments, and the specific structure can be referred to the above embodiment, which will not be repeated here.

In short, in the embedded circuit board of the present application, the magnetic core and the metal base are embedded in the circuit board body at the same time, which can reduce the volume of the circuit board and improve the heat dissipation performance of the circuit board.

The above are only implementations of this application, and do not limit the scope of this application. Any equivalent structure or equivalent process transformation made using the content of the description and drawings of this application, or directly or indirectly applied to other related technologies In the same way, all fields are included in the scope of patent protection of this application.

Claims

A buried circuit board, which includes:

Circuit board main body;

Both the magnetic core and the metal base are embedded in the circuit board main body.
The buried circuit board according to claim 1, wherein a signal transmission layer is provided on two opposite sides of the circuit board main body, and the metal base is electrically connected to the signals located on the opposite sides of the circuit board main body. Transport layer.
The buried circuit board according to claim 2, wherein:

The number of the metal base is more than two, including a first metal base and a second metal base, the first metal base penetrates the magnetic core, and the second metal base is located at the periphery of the magnetic core;

The signal transmission layer includes a wire pattern, and the wire pattern is arranged across the first metal base and the second metal base to form a coil loop capable of transmitting current around the magnetic core.
The buried circuit board according to claim 2, wherein:

The number of the metal base is more than one, including a first metal base, and the first metal base penetrates the magnetic core;

The circuit board main body is provided with a via hole located at the periphery of the magnetic core, the signal transmission layer includes a wire pattern, and the wire pattern is provided across the first metal base and the via hole;

A conductive material is arranged in the via hole for electrically connecting the wire patterns on the two signal transmission layers, thereby forming a coil loop capable of transmitting current around the magnetic core.
The buried circuit board according to claim 2, wherein:

The number of the metal base is more than one, including a first metal base, and the first metal base is located at the periphery of the magnetic core;

The circuit board main body is provided with a through hole penetrating the magnetic core, the signal transmission layer includes a wire pattern, and the wire pattern is provided across the first metal base and the through hole;

A conductive material is arranged in the via hole for electrically connecting the wire patterns on the two signal transmission layers, thereby forming a coil loop capable of transmitting current around the magnetic core.
The buried circuit board according to claim 2, wherein:

The thickness of the magnetic core is smaller than the thickness of the metal base.
The buried circuit board according to claim 1, wherein:

The cross section of the metal base along its thickness direction is rectangular or T-shaped.
The buried circuit board according to claim 1, wherein:

The number of the circuit board main body is more than two, and more than two circuit board main bodies are stacked and arranged, and each of the circuit board main bodies is embedded with the magnetic core and the metal base.
The buried circuit board according to claim 1, wherein:

The metal-based material is at least one of copper and aluminum.
The buried circuit board according to claim 1, wherein:

The material of the magnetic core is manganese-zinc-iron, nickel-zinc-iron or amorphous magnetic material.
A method for manufacturing an embedded circuit board, wherein the manufacturing method includes:

Preparing the main body of the first sub-circuit board;

Forming a first accommodating groove on the main body of the first sub-circuit board, and placing a magnetic core in the first accommodating groove;

Forming a second sub-circuit board main body on the side of the first sub-circuit board main body that exposes the magnetic core to cover the magnetic core;

A second accommodating groove is formed, and the metal base is placed in the second accommodating groove.
11. The manufacturing method according to claim 11, wherein a signal transmission layer is formed on the side of the second sub-circuit board main body away from the first sub-circuit board main body;

After forming the second accommodating groove and placing the metal base in the second accommodating groove, the method further includes:

Forming a conductive layer covering the metal base on the side of the second sub-circuit board where the metal base is exposed, and electrically connecting the conductive layer and the signal transmission layer on the same side of the second sub-circuit board;

The signal transmission layer and the conductive layer are patterned to form a conductive line pattern.
A method for manufacturing an embedded circuit board, wherein the manufacturing method includes:

Preparing the main body of the first sub-circuit board;

Forming a first accommodating groove on the main body of the first sub-circuit board, and placing a metal base in the first accommodating groove;

Forming a second accommodating groove on the main body of the first sub-circuit board, and placing a magnetic core in the second accommodating groove;

A second sub-circuit board main body is formed on the side of the first sub-circuit board main body that exposes the magnetic core to cover the magnetic core.
The manufacturing method according to claim 13, wherein the thickness of the metal base is greater than the thickness of the main body of the first sub-circuit board;

The step of forming a first accommodating groove on the main body of the first sub-circuit board and placing a metal base in the first accommodating groove includes:

The first accommodating groove is formed on the main body of the first sub-circuit board, and the metal base is placed in the first accommodating groove so that the first end of the metal base protrudes from the first The first surface and the second end of the main body of the sub-circuit board are arranged in the main body of the first sub-circuit board;

The step of forming a second accommodating groove on the main body of the first sub-circuit board and placing a magnetic core in the second accommodating groove includes:

Forming the second accommodating groove on the first sub-circuit board main body, so that the notch of the second accommodating groove is provided on the first surface of the first sub-circuit board main body;

Placing the magnetic core in the second accommodating groove;

The step of forming a second sub-circuit board main body on the side of the first sub-circuit board main body that exposes the magnetic core to cover the magnetic core includes:

A second sub-circuit board main body is formed on the first surface of the first sub-circuit board main body to cover the magnetic core, and at the same time, the second sub-circuit board main body is provided with a through hole corresponding to the metal base, So that the first end of the metal base is disposed in the second sub-circuit board main body and the second sub-circuit board main body exposes the first end of the metal base.
14. The manufacturing method according to claim 14, wherein a signal transmission layer is formed on a side of the second sub-circuit board main body away from the first sub-circuit board main body, and the method further comprises:

Forming a conductive layer covering the metal base on the side of the second sub-circuit board where the metal base is exposed, and electrically connecting the conductive layer and the signal transmission layer on the same side of the second sub-circuit board;

The signal transmission layer and the conductive layer are patterned to form a conductive line pattern.