Manufacturing method of buried magnetic circuit board and electronic component

Abstract

The application belongs to the technical field of circuit board manufacturing, and particularly relates to a buried magnetic circuit board manufacturing method and an electronic component. The buried magnetic circuit board manufacturing method comprises the following steps: preparing a substrate, the substrate is prepared with two plates, and the two plates are oppositely arranged; burying a magnetic body, a pressure bearing plate with a predetermined strength is arranged between the two plates, a containing through slot is formed on the pressure bearing plate, and an adhesive layer is arranged on both sides of the pressure bearing plate, a first magnetic body is accommodated in the containing through slot, and the two plates are respectively pressed and adhered by the two sides of the pressure bearing plate under a predetermined temperature and a predetermined pressure; filling, a containing hole is formed on one of the plates, the containing hole penetrates to the first magnetic body, the cross-sectional area of the first magnetic body parallel to the pressure bearing plate is greater than the cross-sectional area of the containing hole parallel to the pressure bearing plate, and a magnetic conductive glue is filled in the containing hole; and solidifying, the magnetic conductive glue is solidified. The application improves the total inductance of the circuit board, and does not need to enlarge the size of the circuit board, which is beneficial to the miniaturization of the circuit board.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of circuit board manufacturing, and particularly relates to a buried magnetic circuit board manufacturing method and an electronic component. BACKGROUND

[0002] At present, with the development of power module PCB, a scheme using buried magnetic technology to replace the traditional inductance component mounting scheme has emerged, which has the advantages of small size and light weight. Since buried magnetic technology does not require soldering points, the reliability performance is also better. However, the industry currently mostly buries a single magnetic core (sheet-shaped or columnar), so that the mutual inductance interaction of the coil and the magnetic core is limited in a single direction. Therefore, the inductance value of the circuit board is small and cannot meet specific requirements.

[0003] The traditional method to increase the inductance value is to increase the number of conductive coils. However, the increase in the number of coils makes the area occupied by the inductance component larger, which is not conducive to the miniaturization of the printed circuit board. Therefore, the prior art needs to be improved. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a buried magnetic circuit board manufacturing method, which aims to solve the problem of how to increase the inductance value of the circuit board.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is:

[0006] In a first aspect, a buried magnetic circuit board manufacturing method is provided, which includes the following steps:

[0007] Preparation of a substrate, the substrate is prepared with two blocks, and the two substrates are arranged opposite to each other;

[0008] Buried magnetic, a pressure plate with a predetermined strength is arranged between the two substrates, a containing through slot is formed on the pressure plate, and an adhesive layer is arranged on both sides of the pressure plate, a first magnet is accommodated in the containing through slot, and the two substrates are respectively pressed and bonded by the two sides of the pressure plate under a predetermined temperature and a predetermined pressure;

[0009] Filling, a containing hole is formed on one of the substrates, the containing hole penetrates to the first magnet, the cross-sectional area of the first magnet parallel to the pressure plate is greater than the cross-sectional area of the containing hole parallel to the pressure plate, and magnetic conductive glue is filled in the containing hole;

[0010] Curing, curing the magnetic conductive glue.

[0011] In one embodiment, the filling step includes the following steps:

[0012] S31: machining a blind hole on the corresponding substrate by a mechanical depth control method;

[0013] S32: processing the blind hole and forming the accommodating hole by a laser ablation method.

[0014] In one embodiment, the filling step further comprises S33: placing a second magnet in the accommodating hole, and the magnetically conductive glue completely wraps the second magnet.

[0015] In one embodiment, the S33 step comprises the following steps:

[0016] In one embodiment, the filling step further comprises S33: placing a second magnet in the accommodating hole, and the magnetically conductive glue completely wraps the second magnet.

[0017] In one embodiment, the filling step further comprises S33: placing a second magnet in the accommodating hole, and the magnetically conductive glue completely wraps the second magnet.

[0018] In one embodiment, the first magnet is in a sheet shape, and the thickness of the first magnet is equal to the thickness of the pressure bearing plate.

[0019] In one embodiment, the second magnet is in a column shape, and the height of the second magnet is less than the depth of the accommodating hole.

[0020] In one embodiment, the cross-sectional shape of the second magnet is circular, square or elliptical, and the shape of the accommodating hole is adapted to the shape of the second magnet.

[0021] In one embodiment, the substrate is a multi-layer structure or a single-layer structure; the multi-layer structure comprises an insulating medium layer and a circuit layer, and the two side surfaces of the insulating medium layer are provided with the circuit layer; the single-layer structure comprises a conductive metal layer; and at least one of the substrates is a multi-layer structure.

[0022] In one embodiment, the substrate is a multi-layer structure or a single-layer structure; the multi-layer structure comprises an insulating medium layer and a circuit layer, and the two side surfaces of the insulating medium layer are provided with the circuit layer; the single-layer structure comprises a conductive metal layer; and at least one of the substrates is a multi-layer structure.

[0023] In one embodiment, the circuit board is provided with two layers, and the two layers are stacked, and each of the second magnets is located between the two first magnets.

[0024] The application has the beneficial effect that: by arranging the first magnet and the magnetic conductive glue in the circuit board, and the first magnet and the magnetic conductive glue respectively improve the inductance of the circuit board in two directions, wherein the first magnet improves the inductance of the circuit board in the horizontal direction, and the magnetic conductive glue improves the inductance of the circuit board in the vertical direction, so as to finally improve the total inductance of the circuit board, without the need to expand the size of the circuit board, which is beneficial to the miniaturization of the circuit board. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the embodiments or exemplary technical descriptions will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0026] Figure 1 The structural schematic diagram of the substrate provided by the embodiments of the present application is shown in the figure.

[0027] Figure 2 The structural schematic diagram of the first magnet before pressing provided by the embodiments of the present application is shown in the figure.

[0028] Figure 3 The structural schematic diagram of the first magnet after pressing provided by the embodiments of the present application is shown in the figure.

[0029] Figure 4 The structural schematic diagram of the blind hole provided by the embodiments of the present application is shown in the figure.

[0030] Figure 5 The structural schematic diagram of the accommodating hole provided by the embodiments of the present application is shown in the figure.

[0031] Figure 6 The structural schematic diagram of the magnetic conductive glue arranged in the accommodating hole provided by the embodiments of the present application is shown in the figure.

[0032] Figure 7 The structural schematic diagram of the magnetic conductive glue and the second magnet arranged in the accommodating hole provided by the embodiments of the present application is shown in the figure.

[0033] Figure 8 The structural schematic diagram of the two circuit board layers stacked and connected provided by the embodiments of the present application is shown in the figure.

[0034] Figure 9 The flowchart of the manufacturing method of the magnetic embedded circuit board provided by the embodiments of the present application is shown in the figure.

[0035] In the figure, various reference signs:

[0036] 10, substrate; 11, insulating dielectric layer; 12, circuit layer; 13, adhesive layer; 21, pressure plate; 31, first magnet; 43, accommodating slot; 41, blind hole; 42, accommodating hole; 32, second magnet; 33, magnetically conductive adhesive; DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0038] It should be noted that when a component is referred to as "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component. The terms "upper", "lower", "left", "right", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. For those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "first", "second" are only for the purpose of convenient description, and cannot be understood as indicating or implying relative importance or implying the number of technical features. The meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0039] Referring to Figure 1 and Figure 9 , the present application provides a method for manufacturing a buried magnetic circuit board, which comprises the following steps:

[0040] S1: two substrates 10 are prepared and arranged opposite to each other; optionally, one of the substrates 10 is arranged flat on a workbench, and the other substrate 10 is located above the substrate 10. According to the size requirements of the production of the layout, the copper-clad plate is cut into substrates 10 of a predetermined size, wherein the copper-clad plate is a double-sided copper-clad plate.

[0041] S2: burying the magnet, a pressure plate 21 with a predetermined structural strength is arranged between the two substrates 10, an accommodating slot 43 is formed on the pressure plate 21, and an adhesive layer 13 is arranged on both side surfaces of the pressure plate 21, a first magnet 31 is accommodated in the accommodating slot 43, and the two side surfaces of the pressure plate 21 are respectively pressed and adhered to the two substrates 10 under a predetermined temperature and a predetermined pressure. Optionally, the two side surfaces of the pressure plate 21 are respectively pressed and adhered to the two substrates 10 under a predetermined temperature and a predetermined pressure, and a predetermined time is maintained, so that the two substrates 10 and the pressure plate 21 are fully contacted and pressed.

[0042] Optionally, the first magnet 31 is made of a material capable of generating a magnetic field, and the first magnet 31 increases the inductance of the circuit board in the horizontal direction. It can be understood that the size of the accommodating through slot 43 is matched with the size of the first magnet 31, and the first magnet 31 is completely accommodated in the accommodating through slot 43. Optionally, there is a gap between the first magnet 31 and the inner wall of the accommodating through slot 43, so that part of the adhesive layer fills the gap during the high-temperature pressing process, so that the first magnet 31 is firmly connected. The pressure plate 21 has a predetermined structural strength, so that the first magnet 31 will not be damaged by the pressure during the pressing process.

[0043] Optionally, the pressure plate 21 is the insulating medium layer 11, which can be made of a resin material with a flame resistance level of FR4.

[0044] Optionally, the insulating medium layer can be a light plate, which is a double-sided copper-clad plate and is formed after etching the double-sided copper layer.

[0045] Optionally, the adhesive layer 13 can be made of a resin material that will melt and flow under high-temperature and high-pressure conditions. The type of resin material can be epoxy resin, or it can be selected according to the application field of the circuit board, such as the circuit board being applied in the power module field, and the type of resin material can be polyimide resin to improve the voltage resistance performance of the circuit board.

[0046] Optionally, a press is used for pressing and bonding, and before pressing and bonding, upper and lower steel plates and silicone pads and other buffer materials are added to make the pressure distribution uniform during pressing and improve the pressing effect of the circuit board.

[0047] Please refer to Figure 4 and Figure 6 , S3: filling, a accommodating hole 42 is formed on one of the substrates 10, the accommodating hole 42 penetrates to the first magnet 31, the cross-sectional area of the first magnet 31 parallel to the pressure plate 21 is greater than the cross-sectional area of the accommodating hole 42 parallel to the pressure plate 21, and the magnetic conductive glue 33 is filled in the accommodating hole 42;

[0048] S4: curing, curing the magnetic conductive glue 33.

[0049] Please refer to Figure 4 and Figure 6 , optionally, the accommodating hole 42 is filled with a magnetic composite material by vacuum screen printing, wherein the magnetic composite material is also called magnetic glue or magnetic conductive glue 33, and includes magnetic particles and a resin material. In the curing step, the magnetic composite material is cured, and the magnetic composite material overflowing out of the accommodating hole 42 on the surface of the substrate 10 is ground and removed, so that the surface of the circuit board is flat. The cured magnetic composite material is bonded with the first magnet 31 to form an integral whole.

[0050] Referring to Figure 4 and Figure 6 It can be understood that the magnetic conductive glue 33 improves the inductance of the circuit board in the vertical direction.

[0051] By arranging the first magnet 31 and the magnetic conductive glue 33 in the circuit board, and the first magnet 31 and the magnetic conductive glue 33 respectively improve the inductance of the circuit board in two directions, wherein the first magnet 31 improves the inductance of the circuit board in the horizontal direction, and the magnetic conductive glue 33 improves the inductance of the circuit board in the vertical direction, thereby finally improving the total inductance of the circuit board, and without the need to expand the size of the circuit board, which is conducive to the miniaturization of the circuit board.

[0052] Referring to Figure 4 and Figure 6 In one embodiment, the filling step S3 comprises the following steps:

[0053] S31: machining the blind hole 41 on the corresponding substrate 10 by a mechanical depth control method;

[0054] Referring to Figure 4 and Figure 6 Optionally, the blind hole 41 is arranged opposite to the position of the first magnet 31, so that the surface part of the first magnet 31 can be exposed subsequently. By the mechanical depth control milling method, the copper layer, the core plate, or part of the dielectric layer at the corresponding position is removed. Because there is a machining precision error in the mechanical depth control milling, if all the dielectric layers above the first magnet 31 are removed at one time, the first magnet 31 may be damaged. Therefore, at least part of the dielectric layer above the first magnet 31 needs to be reserved in the S31 step.

[0055] S32: machining the blind hole 41 and forming the accommodating hole 42 by a laser ablation method;

[0056] Referring to Figure 4 and Figure 6 Optionally, the laser ablation is used to remove the remaining dielectric layer above the first magnet 31 and form the accommodating hole 42 from the blind hole 41, so that the surface part of the first magnet 31 is partially exposed through the accommodating hole 42. Optionally, the laser in the laser ablation process can be a CO2 laser or a UV laser.

[0057] Optionally, at least one accommodating hole 42 needs to be machined, and in the embodiment, three accommodating holes 42 are arranged, and the magnetic conductive glue 33 is arranged in each accommodating hole 42.

[0058] Referring to Figure 6 and Figure 8 In one embodiment, the filling step S3 further comprises S33: placing the second magnet 32 in the accommodating hole 42, and the magnetic conductive glue 33 completely wraps the second magnet 32.

[0059] It can be understood that the magnetic conductive glue 33 has a low magnetic permeability after curing. The second magnet 32 is arranged in the magnetic conductive glue 33 to increase the magnetic permeability of the magnetic conductive glue 33. Alternatively, the second magnet 32 and the first magnet 31 are made of the same material.

[0060] Referring to Figure 6 and Figure 8 Alternatively, the second magnet 32 is also made of a material capable of generating a magnetic field, and the second magnet 32 increases the inductance of the circuit board in the vertical direction. Thus, the first magnet 31 and the second magnet 32 increase the inductance of the circuit board in the horizontal direction and the vertical direction, respectively.

[0061] Referring to Figure 6 and Figure 8 Alternatively, the magnetic permeability of the magnetic composite material after curing is less than the magnetic permeability of the second magnet 32 or the first magnet 31. In order to improve the performance of the circuit board, the second magnet 32 is arranged in the accommodating hole 42 to increase the magnetic permeability of the magnetic conductive glue 33.

[0062] Referring to Figure 6 and Figure 8 It can be understood that the filling amount of the magnetic conductive glue 33 plus the volume of the second magnet 32 is greater than the volume of the accommodating hole 42, so that the accommodating hole 42 is filled, and there is no recess at the hole opening of the accommodating hole 42. After curing, the excess magnetic conductive glue 33 is removed by grinding to make the surface of the substrate 10 flat.

[0063] Alternatively, the magnetic composite material is used as an adhesive to increase the magnetic permeability while bonding the second magnet 32, so that the magnetic permeability of the circuit board is better.

[0064] Referring to Figure 6 and Figure 8 Alternatively, the cross-sectional shape of the second magnet 32 is adapted to the cross-sectional shape of the accommodating hole 42.

[0065] Referring to Figure 6 and Figure 8 In one embodiment, the S33 step includes the following steps:

[0066] S331: once glue is introduced, the magnetic conductive glue 33 is introduced into the accommodating hole 42, the volume of the magnetic conductive glue 33 introduced in the once glue process is less than the volume of the accommodating hole 42, and the second magnet 32 is arranged in the accommodating hole 42, and the side surface of the second magnet 32 is arranged in the accommodating hole 42. The hole wall is arranged with a gap; the curing step includes pre-curing the once glue step.

[0067] Optionally, in the first glue printing process, the magnetic conductive glue 33 is introduced into the accommodating hole 42 first, the magnetic conductive glue 33 fills part of the accommodating hole 42, then the second magnet 32 is placed, and the magnetic conductive glue 33 is pre-solidified.

[0068] Optionally, the pre-solidification temperature ranges from 110 to 130 °C, and the duration ranges from 30 to 60 minutes.

[0069] Please refer to Figure 6 and Figure 8 S332: second glue printing, the magnetic conductive glue 33 is introduced into the accommodating hole 42, and the magnetic conductive glue 33 of the first glue printing and the magnetic conductive glue 33 of the second glue printing together wrap the second magnet 32; the solidification step further comprises final solidification of the second glue printing step.

[0070] Optionally, in the second glue printing process, the gap between the second magnet 32 and the hole wall of the accommodating hole 42 is completely filled with the magnetic conductive glue 33. In order to conveniently and quickly place the second magnet 32 and make the second magnet 32 in the accommodating hole 42 in the central position, a jig can be used for assistance. The jig can use a light plate, an acrylic plate and the like, and a positioning hole corresponding to the position of the accommodating hole 42 is opened, the hole diameter of the positioning hole is smaller than the hole diameter of the accommodating hole 42, so as to limit the distance between the first magnet 31 and the four surrounding side walls of the accommodating hole 42 to be basically equal when the first magnet 31 is placed; the hole diameter of the positioning hole is greater than the outer diameter of the second magnet 32, so as to facilitate the second magnet 32 to pass through the positioning hole.

[0071] Optionally, the final solidification temperature ranges from 140 to 160 °C, and the duration ranges from 60 to 90 minutes.

[0072] Optionally, the cured circuit board is ground to remove the magnetic conductive glue 33 overflowing during the printing of the magnetic conductive glue 33, and the surface of the magnetic conductive glue 33 is smooth, and the grinding can use a ceramic grinding brush and a non-woven cloth grinding.

[0073] Please refer to Figure 6 and Figure 8 In one embodiment, the first magnet 31 is in the form of a sheet, and the thickness of the first magnet 31 is equal to the thickness of the pressure bearing plate 21.

[0074] Please refer to Figure 1 and Figure 3Optionally, the two side surfaces of the first magnet 31 are arranged flush with the two side surfaces of the pressure plate 21. The thickness of the pressure plate 21 is consistent with the thickness of the first magnet 31, that is, when the first magnet 31 is placed in the accommodating through slot 43, the upper surface of the first magnet 31 is flush with the upper surface of the pressure plate 21, and the lower surface of the first magnet 31 is flush with the lower surface of the pressure plate 21. In the pressure bonding structure of the embedded magnetic core, because the pressure plate 21 is a cured adhesive material, the state does not change or only changes very slightly during pressure bonding. The use of the pressure plate 21 with a thickness consistent with that of the first magnet 31 and the provision of the accommodating through slot 43 can reduce the pressure borne by the first magnet 31 and avoid damage to the first magnet 31 during pressure bonding.

[0075] Referring to Figure 6 and Figure 8 In one embodiment, the second magnet 32 is in the shape of a column, and the height of the second magnet 32 is less than the depth of the accommodating hole 42, so that the second magnet 32 can be completely accommodated in the accommodating hole 42.

[0076] Optionally, the cross-sectional area of the second magnet 32 is less than the area of the surface of the first magnet 31 facing the second magnet.

[0077] Optionally, the cross-sectional shape of the second magnet 32 is circular, square or elliptical, and the shape of the accommodating hole 42 is adapted to the shape of the second magnet 32.

[0078] In one embodiment, the substrate 10 is a multilayer structure or a single-layer structure. The multilayer structure includes an insulating dielectric layer 11 and a circuit layer 12, and the two side surfaces of the insulating dielectric layer 11 are provided with the circuit layer 12. The single-layer structure includes a conductive metal layer. At least one substrate 10 is a multilayer structure.

[0079] Referring to Figure 1 and Figure 3 Optionally, the substrate 10 of the multilayer structure is a copper-clad substrate 10, that is, the middle of the substrate 10 is an insulating dielectric layer 11, and the two opposite side surfaces of the insulating dielectric layer 11 are provided with a circuit layer 12, which is a conductive copper layer. Optionally, the two sides of the insulating dielectric layer 11 can each be provided with a plurality of circuit layers 12, and any two circuit layers on the same side are bonded by an adhesive layer 13.

[0080] Optionally, the conductive metal layer is a copper foil.

[0081] Referring to Figure 1 and Figure 3 Optionally, the circuit layer 12 provided adjacent to the adhesive layer 13 is an inner circuit layer 12, which is sequentially subjected to processes such as dry film lamination, exposure, development, etching and film stripping to complete the production of a predetermined circuit layer 12.

[0082] The outer circuit layer 12 is the outer layer of the pressure bonding structure and serves as a protective copper layer.

[0083] In one embodiment, a plurality of circuit layers 12 are spaced apart on one side surface of the insulating dielectric layer 11, and each circuit layer 12 is connected to an adhesive layer 13. In the step of embedding the first magnet 31, an adhesive layer 13 is filled between any two adjacent circuit layers 12.

[0084] Please see Figure 1 and Figure 3 It is understandable that during high-temperature pressing, the molten adhesive layer 13 will flow and fill the gap between two adjacent circuit layers 12, making the first magnet 31 bonded to the substrate 10 more firmly.

[0085] Optionally, the method for manufacturing a magnetically embedded circuit board also includes drilling, drilling and processing the circuit board with embedded magnets, and making the circuit layers 12 conductive through metallized holes.

[0086] Optionally, the method of manufacturing the embedded magnetic circuit board further includes providing a sub-circuit layer 12 on the substrate 10 with the receiving hole 42, and the sub-circuit layer 12 is pressed and connected to the circuit board through the adhesive layer 13.

[0087] Please see Figure 1 and Figure 3 It is understandable that the sub-circuit layer 12 can be a single-sided copper-clad board, a double-sided copper-clad board, a multilayer circuit board without embedded magnets, or a multilayer circuit board with embedded magnets.

[0088] In this embodiment, the sub-circuit layer 12 is a circuit board with embedded magnets and manufactured by the above-described method for manufacturing embedded magnet circuit boards.

[0089] Please see Figure 8 The present invention also proposes an electronic component, which includes a circuit board manufactured by the above-described method for manufacturing a buried magnetic circuit board. Since this electronic component adopts all the technical solutions of all the above embodiments, it also has all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0090] In one embodiment, the electronic component further includes a coil winding disposed on a circuit board.

[0091] Optionally, the coil winding includes an input coil winding disposed relative to the first magnet 31 and a coupling coil winding arranged circumferentially around the second magnet 32. The input coil winding and the coupling coil winding are disposed relative to the first magnet 31 and the second magnet 32, respectively, and together form a specific inductive element, such as a transformer.

[0092] In one embodiment, two circuit boards are provided, which are stacked on top of each other, and each second magnet 32 ​​is located between two first magnets 31.

[0093] The two circuit boards are connected by high-temperature compression bonding through the adhesive layer 13.

[0094] The above merely provides optional embodiments of the present application, but not for limiting the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A method for manufacturing a buried magnetic circuit board, characterized by comprising the steps of: The method comprises the following steps: ​ Preparation of a substrate, the substrate is prepared with two pieces, two said substrate is arranged opposite; Buried magnetic, the pressure plate with a predetermined strength is arranged between the two said substrate, the pressure plate is provided with a containing through slot, and the adhesive layer is arranged on both sides of the pressure plate, the first magnet is accommodated in the containing through slot, and the two sides of the pressure plate are respectively pressed and bonded to two said substrate under predetermined temperature and pressure; there is a gap between the first magnet and the inner wall of the containing through slot, and part of the adhesive layer fills the gap during the pressing process; Filling, a containing hole is formed in one of the substrates, the containing hole penetrates to the first magnet, the cross-sectional area of the first magnet parallel to the pressure plate is greater than the cross-sectional area of the containing hole parallel to the pressure plate, and the magnetic conductive glue is filled in the containing hole; Solidification, solidification of the magnetic conductive glue, so as to be integrated with the first magnet.

2. The method of claim 1, wherein: The filling step comprises the following steps: S31: processing blind hole on the corresponding substrate by mechanical depth control method; S32: processing the blind hole by laser ablation method and forming the containing hole.

3. The method of claim 1, wherein the method further comprises: The filling step further comprises S33: placing a second magnet in the containing hole, and the magnetic conductive glue completely wraps the second magnet. ​ 4. The method of claim 3, wherein the step of forming the magnetic field generating layer comprises the steps of: forming a magnetic layer on the surface of the substrate; and forming a non-magnetic layer on the magnetic layer. The S33 step comprises the following steps: S331: one-time glue printing, the magnetic conductive glue is introduced into the containing hole, the volume of the magnetic conductive glue introduced in the one-time glue printing is less than the volume of the containing hole, and the second magnet is arranged in the containing hole, and the side surface of the second magnet is arranged with a gap between the hole wall of the containing hole; the solidification step comprises pre-solidification of the one-time glue printing step; S332: two-time glue printing, the magnetic conductive glue is introduced into the containing hole, and the magnetic conductive glue of the one-time glue printing and the magnetic conductive glue of the two-time glue printing jointly wrap the second magnet; the solidification step further comprises final solidification of the two-time glue printing step.

5. The method of claim 1-4, wherein: The first magnet is in sheet shape, and the thickness of the first magnet is equal to the thickness of the pressure plate.

6. The method of claim 3-4, wherein: The second magnet is in column shape, and the height of the second magnet is less than the depth of the containing hole.

7. The method of claim 6, wherein the method further comprises: The cross-sectional shape of the second magnet is circular, square or elliptical, and the shape of the containing hole is matched with the shape of the second magnet. ​ 8. The method of claim 1-4, wherein: the magnetic field is buried in the circuit board. The substrate is a multilayer structure or a single layer structure; the multilayer structure comprises an insulating medium layer and a circuit layer, both side surfaces of the insulating medium layer are provided with the circuit layer; the single layer structure comprises a conductive metal layer; wherein at least one of the substrates is a multilayer structure.

9. An electronic component, characterized by The circuit board prepared by the method for preparing a buried magnetic circuit board according to any one of claims 3, 4, 6, 7, the electronic element further comprises a coil winding arranged on the circuit board.

10. The electronic component of claim 9, wherein: The circuit board is provided with two, two said circuit board is arranged in layers, and each said second magnet is located between two said first magnet.

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