Method for manufacturing a circuit board structure and circuit board structure, power supply device

Abstract

The application provides a circuit board structure, a manufacturing method thereof and a power supply device using the circuit board structure. The circuit board structure comprises two magnetic cores, a core layer, a first circuit unit and a plurality of second circuit units which are sequentially arranged on opposite sides of the core layer, a plurality of first through holes, second through holes and two spaced accommodation holes are arranged through the core layer, the second through holes are located between the two accommodation holes, the first through holes are arranged on the side of the accommodation hole away from the first through holes, the magnetic cores are arranged in the accommodation holes, and an air gap is formed between the two magnetic cores. The circuit board structure can form an air gap with a specific size between the two magnetic cores by opening the accommodation hole, thereby reducing magnetic field leakage, reducing loss, increasing current density, achieving high power and miniaturization.

Description

Technical Field

[0001] This application relates to the field of DC transformers, and more particularly to a method for manufacturing a circuit board structure, the circuit board structure, and a power supply device. Background Technology

[0002] Current technology embeds magnetic cores into circuit boards to form transformer modules, meeting the trend towards miniaturization and thinner designs in power modules. However, current transformer modules cannot meet the high-power requirements of transformers, and current transmission losses are significant. Furthermore, for inductors or transformers, the magnetic core stores magnetic field energy and transmits changing magnetic flux. In some soft-switching circuits, transformers often use air gaps of specific sizes to create suitable magnetizing inductance values. In existing transformer modules, air gaps are often constructed using air gap adhesive, resulting in poor precision in air gap length and high manufacturing difficulty. The number of air gaps used is also often limited, leading to excessive concentration of magnetic field energy, a significant proximity effect near the air gaps, and substantial losses around the perimeter. Summary of the Invention

[0003] To address the shortcomings of the existing technology, this application provides a circuit board structure that can achieve miniaturization by embedding a magnetic core, while increasing current density, achieving high power, reducing current loss, and reducing magnetic field leakage and losses by opening receiving holes to achieve air gaps of a specific size and number.

[0004] In addition, it is necessary to provide a method for manufacturing the above-mentioned circuit board structure.

[0005] One embodiment of this application provides a circuit board structure including two magnetic cores, a core layer, and a first circuit unit and a plurality of second circuit units sequentially stacked on opposite sides of the core layer. The core layer is provided with a plurality of first through holes, second through holes, and two receiving holes. The second through holes are located between the two receiving holes, and the first through holes are disposed on the side of the two receiving holes away from the second through holes. Each magnetic core is disposed in one of the receiving holes, and at least one air gap is formed between the two magnetic cores. The first circuit unit includes a first circuit layer, and the second circuit unit includes a second circuit layer and an outer conductor. The first through holes and the second through holes are electrically connected to the first circuit layer, and the outer conductor is electrically connected to the first circuit layer and the second circuit layer, as well as electrically connected to two adjacent second circuit layers.

[0006] This application also provides a method for manufacturing a circuit board structure, including the following steps:

[0007] A copper-clad substrate is provided, the copper-clad substrate includes a core layer and inner circuit layers disposed on opposite sides of the core layer, a plurality of first vias, a second via, and two spaced-apart receiving holes are disposed through the copper-clad substrate, the second vias are located between the two receiving holes, the first vias are disposed on the side of the two receiving holes away from the second vias, and both the first vias and the second vias are electrically connected to the two inner circuit layers;

[0008] An add-layer unit is provided on one side of the copper-clad substrate. The add-layer unit includes a stacked copper foil layer, a first insulating layer and a first adhesive layer. The first adhesive layer seals one end of the receiving hole. A magnetic core is provided in each of the two receiving holes. At least one air gap is formed between the two magnetic cores.

[0009] Another layering unit is provided on the other side of the copper-clad substrate. Multiple inner conductors are formed through the layering unit, and the copper foil layer is patterned to form a first circuit layer. The first circuit layer, the first insulating layer, the first adhesive layer, and the inner conductors together form a first circuit unit. The inner conductors are electrically connected to the first circuit layer and the inner circuit layer to obtain an intermediate body.

[0010] Multiple second circuit units are stacked on opposite sides of the intermediate body. Each second circuit unit includes an outer conductor, a stacked second circuit layer, a second insulating layer, and a second adhesive layer. The second adhesive layer covers the first circuit layer. The outer conductor penetrates the second insulating layer and the second adhesive layer to electrically connect the first circuit layer and the second circuit layer, as well as to electrically connect two adjacent second circuit layers, thereby obtaining a circuit board structure.

[0011] This application also provides a method for manufacturing a circuit board structure, including the following steps:

[0012] A core layer is provided, through which two spaced-apart receiving holes are formed;

[0013] A magnetic core is disposed in each of the receiving holes, and at least one air gap is formed between two magnetic cores. An enhancement unit is disposed on each of the opposite sides of the core layer. Each enhancement unit includes a stacked copper foil layer and a first adhesive layer, with the first adhesive layer facing the core layer.

[0014] A first through-hole and a second through-hole are formed through the added-layer unit and the core layer, and each copper foil layer is patterned to form a first circuit layer. The first through-hole is disposed around the two receiving holes, and the second through-hole is disposed between the two receiving holes. The first through-hole and the second through-hole are electrically connected to the two first circuit layers to obtain an intermediate body.

[0015] Multiple second circuit units are stacked on opposite sides of the intermediate body. Each second circuit unit includes an outer conductor, a stacked second circuit layer, and a second adhesive layer. The second adhesive layer covers the first circuit layer. The outer conductor penetrates the second adhesive layer to electrically connect the first circuit layer and the second circuit layer, as well as to electrically connect two adjacent second circuit layers, thereby obtaining a circuit board structure.

[0016] This application also provides a power supply device, including a chip, a motherboard, and the aforementioned circuit board structure, wherein the circuit board structure and the chip are respectively soldered to opposite sides of the motherboard.

[0017] The circuit board structure provided in this application, by creating spaced-apart receiving holes in the core layer and embedding magnetic cores within these holes, allows for precise control of the number and size of air gaps between the magnetic cores. This enables the arrangement of multiple magnetic core segments and multiple air gaps, thereby reducing energy loss and magnetic field leakage. Embedding the magnetic cores within the circuit board structure facilitates the miniaturization of transformer modules. By adding first and multiple second circuit units to both sides of the core layer, the current density of this circuit board structure can reach up to 20 A / mm². 2 This enables high power output, reduces losses during high current transmission, shortens the current transmission path, increases the heat dissipation area, and improves power supply utilization. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of the copper-clad substrate provided in the first embodiment of this application.

[0019] Figure 2 For Figure 1 The diagram shows a cross-sectional view of the copper-clad substrate after the first through-hole, the second through-hole, and the receiving hole are provided.

[0020] Figure 3 for Figure 2 The diagram shows a cross-sectional view of the copper-clad substrate along line III-III.

[0021] Figure 4 For Figure 2 The diagram shows a cross-section after a first copper-clad layer is provided on one side of the receiving hole and a first magnetic core and a second magnetic core are placed inside the receiving hole.

[0022] Figure 5 for Figure 4 The diagram shows a cross-sectional view of the first and second magnetic cores along line V-V.

[0023] Figure 6 For Figure 4 The diagram shows a cross-section of the other side of the receiving hole after a second copper layer has been applied.

[0024] Figure 7 To be Figure 6 The diagram shows a cross-section of the third and fourth metal layers patterned to form the second and fourth circuit layers, and the in-hole electroplating to form the inner and outer conductors.

[0025] Figure 8 This is a cross-sectional schematic diagram of the circuit board structure provided in the first embodiment of this application.

[0026] Figure 9 This is a cross-sectional schematic diagram of the power supply device provided in the first embodiment of this application.

[0027] Figure 10 for Figure 9 The top view of the power supply device shown.

[0028] Figure 11 for Figure 9 The power supply device shown is shown from below.

[0029] Figure 12 This is a cross-sectional schematic diagram of the core layer provided in the second embodiment of this application.

[0030] Figure 13 For Figure 12 The diagram shows a cross-section of the core layer after the inclusion holes have been installed.

[0031] Figure 14 For Figure 13 The diagram shows a cross-section of the core layer after a release film has been applied to one side.

[0032] Figure 15 For Figure 14 The diagram shows a cross-sectional view after the first and second magnetic cores are installed inside the receiving hole.

[0033] Figure 16 For Figure 15 The diagram shows a cross-sectional view after the first and second fixing adhesive layers are respectively installed in the gap between the first and second magnetic cores and the receiving hole.

[0034] Figure 17 To be Figure 16 The diagram shows a cross-section after the release film has been removed.

[0035] Figure 18 For Figure 17 The diagram shows a cross-section after the first copper cladding layer and the second copper cladding layer are respectively installed on both sides of the core layer.

[0036] Figure 19 To be Figure 18 The diagram shows a cross-sectional view of the third and fourth metal layers after they have been patterned to form the second and fourth circuit layers.

[0037] Figure 20This is a cross-sectional schematic diagram of the circuit board structure provided in the second embodiment of this application.

[0038] Explanation of main component symbols

[0039] Circuit board structure 100, 200 First circuit unit 50, 50a

[0040] Copper-clad substrate 10 First circuit layers 51, 51a

[0041] Core layer 11, 11a inner conductive body 52

[0042] Metal layer 12, intermediates 55 and 55a

[0043] First through holes 141, 141a; Second circuit units 60, 60a

[0044] Second vias 142, 142a; Second circuit layers 61, 61a

[0045] Containing holes 16, 16a, solder pad 612

[0046] Gap 161, 161a Second insulation layer 62

[0047] Sub-hole 162 Second adhesive layer 63, 63a

[0048] Spacing 164, outer conductors 64, 64a

[0049] Release film 18, solder resist layer 70

[0050] Inner circuit layer 20, opening 72

[0051] Magnetic core 30, 30a power supply equipment 1000

[0052] Sub-core 301, Mainboard 210

[0053] Fixing adhesive layers 302, 302a, pad 212

[0054] Body 31, Chip 220

[0055] Protrusion 32, Solder paste 222

[0056] Air gap 34, compensation parts 230

[0057] Add-in unit 40, 40a, thickness direction Z

[0058] Copper foil layers 41, 41a, first horizontal direction X

[0059] First insulating layer 42 Second horizontal direction Y

[0060] First adhesive layer 43, 43a

[0061] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0062] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0063] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. When a component is said to be "set on" another component, it can be directly set on the other component or there may be an intervening component.

[0064] Please see Figures 1 to 8 The first embodiment of this application provides a method for manufacturing a circuit board structure 100, the method comprising the steps of:

[0065] For step S11, please refer to [link / reference]. Figure 1 A copper-clad substrate 10 is provided, the copper-clad substrate 10 having a thickness direction Z, and the copper-clad substrate 10 including a metal layer 12, a core layer 11 and a metal layer 12 stacked along the thickness direction Z.

[0066] The core layer 11 is made of at least one of liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE), epoxy glass fiber (FR4), and fusible polytetrafluoroethylene (PFA). In this embodiment, the core layer 11 is made of FR4, and the metal layer 12 is copper foil.

[0067] For step S12, please refer to [link / reference]. Figure 2 Along the thickness direction Z, a plurality of first through holes 141, second through holes 142 and two receiving holes 16 are formed through the copper-clad substrate 10.

[0068] In this embodiment, two receiving holes 16 are spaced apart, and a plurality of second through holes 142 are disposed through the copper-clad substrate 10 located between the two receiving holes 16. A plurality of first through holes 141 are disposed on the copper-clad substrate 10 on the side of the receiving holes 16 away from the second through holes 142. In some embodiments, the distance between any two first through holes 141, between any two adjacent second through holes 142, and between the first through hole 141 and the receiving hole 16, and between the second through hole 142 and the receiving hole 16, is less than 0.2 mm.

[0069] In some embodiments, please refer to Figure 3 Each of the receiving holes 16 includes a plurality of spaced sub-holes 162, and a gap 164 is formed between each of the sub-holes 162 and between two receiving holes 16. The plurality of sub-holes 162 are connected end to end to form a generally U-shaped receiving hole 16, and two receiving holes 16 are arranged opposite to each other.

[0070] Step S12 further includes: patterning the two metal layers 12 to form an inner circuit layer 20, wherein the first via 141 and the second via 142 are electrically connected to the two inner circuit layers 20.

[0071] Specifically, step S12 includes the following steps:

[0072] Step S121: A plurality of first through holes and second through holes (not shown) are formed in the copper-clad substrate 10 by mechanical drilling.

[0073] Step S122: Electroplating is performed in the first through hole and the second through hole to form the first through hole 141 and the second through hole 142;

[0074] In step S123, the metal layer 12 is etched to form the inner circuit layer 20. The first via 141 and the second via 142 are both electrically connected to the two inner circuit layers 20.

[0075] Step S124: The receiving hole 16 is formed through the copper-clad substrate 10.

[0076] For step S13, please refer to [link / reference]. Figure 4 An extension unit 40 is provided on one side of the receiving hole 16, and a magnetic core 30 is provided in each of the two receiving holes 16.

[0077] The inner circuit layer 20, the first through hole 141, the inner circuit layer 20 and the second through hole 142 are sequentially electrically connected to form an induction coil (not shown) surrounding the magnetic core 30.

[0078] The layering unit 40 includes a stacked copper foil layer 41, a first insulating layer 42, and a first adhesive layer 43. The first adhesive layer 43 seals one end of the receiving hole 16, the first insulating layer 42 partially covers the inner circuit layer 20, and one end of the magnetic core 30 contacts the first adhesive layer 43.

[0079] In some embodiments, a gap 161 is formed between the magnetic core 30 and the receiving hole 16. Step S3 further includes: providing a fixing adhesive layer 302 within the gap 161.

[0080] The first insulating layer 42 can be made of polyimide (PI), the first adhesive layer 43 can be made of pure adhesive, and the fixing adhesive layer 302 can be made of epoxy resin. The total thickness of the first insulating layer 42 and the first adhesive layer 43 can be 20 μm.

[0081] Please see Figure 5 In this embodiment, the two magnetic cores 30 are non-closed U-shaped magnetic cores, and the shapes of the magnetic cores 30 and the receiving hole 16 are adapted to each other. The magnetic core 30 includes a body portion 31 and protrusions 32 connected to both ends of the body portion 31. The protrusions 32 of the two magnetic cores 30 are arranged opposite to each other, so that the two magnetic cores 30 surround each other to form a complete magnetic circuit.

[0082] In some embodiments, the magnetic core 30 includes a plurality of sub-cores 301, each sub-core 301 being placed in a corresponding sub-hole 162. Due to the presence of the spacing 164, an air gap 34 is formed between every two sub-cores 301 and at the connection point of two cores 30. The air gap 34 allows the equivalent magnetic flux of the inductor / transformer to decrease, thereby constructing a suitable inductance value. The control of the size of the air gap 34 has a critical impact on the circuit operation. In this embodiment, the width of each air gap 34 is 0.2mm ± 20μm.

[0083] In this application, the method of internally excavating the receiving hole 16 is adopted. By utilizing the high precision characteristics of PCB processing technology, the processing method of multi-segment magnetic core of transformer can be realized, reducing the length of each air gap 34, thereby reducing magnetic field leakage.

[0084] Step S14, please refer to Figure 6 Along the thickness direction Z, another layering unit 40 is provided on the other side of the receiving hole 16 and pressed together.

[0085] The two layer-addition units 40 have the same structure, that is, the two first adhesive layers 403 respectively seal the opposite ends of the receiving hole 16, and the first adhesive layer 403 covers the inner circuit layer 20.

[0086] For step S15, please refer to [link / reference]. Figure 7Two copper foil layers 401 are patterned to form a first circuit layer 51, and an inner conductor 52 is provided through the first insulating layer 42 to electrically connect the first circuit layer 51 and the inner circuit layer 20. The first circuit layer 51, the first insulating layer 42 and the first adhesive layer 43 together form a first circuit unit 50, and an intermediate body 55 is obtained.

[0087] The first circuit layer 51 is connected to the inner circuit layer 20 via the inner conductor 52, thereby the first circuit layer 51 is electrically connected in sequence to the first through hole 141, the first circuit layer 51 and the second through hole 142 to form an induction coil around the magnetic core 30.

[0088] Specifically, step S15 includes:

[0089] Multiple blind holes (not shown) are provided through the copper foil layer 41 and the first insulating layer 42;

[0090] The inner conductive body 52 is formed by electroplating inside the blind hole, and a surface-plated metal layer (not shown) is formed on the surface of the copper foil layer 41 opposite to the first insulating layer 42.

[0091] The copper foil layer 41 and the surface-plated metal layer are etched to form the first circuit layer 51.

[0092] Step S16, please refer to Figure 8 Along the thickness direction Z, at least one second circuit unit 60 is added to each of the opposite sides of the intermediate body 55 to form a circuit board structure 100.

[0093] The second circuit unit 60 has a structure substantially the same as the first circuit unit 50. The second circuit unit 60 includes a stacked second circuit layer 61, a second insulating layer 62, and a second adhesive layer 63, with the second adhesive layer 63 covering the first circuit layer 51. The second circuit unit 60 also includes a plurality of outer conductors 64 penetrating the second insulating layer 62 and the second adhesive layer 63, the outer conductors 64 electrically connecting the second circuit layer 61 and the first circuit layer 51. The second circuit layer 61 has a plurality of solder pads 612.

[0094] In this embodiment, three second circuit units 60 are stacked on opposite sides of the intermediate body 55, and adjacent second circuit layers 61 are electrically connected through the outer conductor 64. Thus, the magnetic core 30 has five interconnected circuit layers on opposite sides, that is, the magnetic core 30 is wound with five layers of induction coils, thereby forming a transformer structure.

[0095] Both the second insulating layer 62 and the first insulating layer 42 are made of polyimide (PI). The linewidth and line spacing of the first circuit layer 51 and the second circuit layer 61 are 0.15 mm (6 mil). Multiple outer conductors 64 and inner conductors 52 are formed using blind via filling electroplating technology. The width of the outer conductors 64 and inner conductors 52 facing the core layer 11 can be 0.15 mm, and the width of the side facing away from the core layer 11 can be 0.3 mm. The copper thickness of the holes in the outer conductors 64 and inner conductors 52 is 50 μm-70 μm. The thickness of the second insulating layer 62 is 3 μm-7 μm, enabling a voltage withstand capability of over 1000V. The copper thickness of the second circuit layer 61 is ≥70 μm, combined with the outer conductors 64 formed by advanced blind via filling electroplating, allowing a current density as high as 20 A / mm². 2 This achieves high power output. The entire circuit board structure 100 utilizes ultra-thin layering, resulting in a total thickness of ≤2mm.

[0096] In some embodiments, step S6 further includes: providing a solder resist layer 70 on the outermost surface of the second circuit layer 61, the solder resist layer 70 having a plurality of openings 72 through which a plurality of solder pads 612 are exposed.

[0097] Please see Figure 8 The first embodiment of this application also provides a circuit board structure 100, including two magnetic cores 30 and a core layer 11, with inner circuit layers 20, first circuit units 50 and a plurality of second circuit units 60 stacked sequentially on opposite sides of the core layer 11. The core layer 11 is provided with a first through hole 141, a second through hole 142 and two receiving holes 16. The first through hole 141 is located on the side of the two receiving holes 16 away from the second through hole 142, and the second through hole 142 is located between the two receiving holes 16. Each magnetic core 30 is respectively disposed in a corresponding receiving hole 16. The first through hole 141 and the second through hole 142 are electrically connected to the two inner circuit layers 20, thereby the two inner circuit layers 20, the first through hole 141 and the second through hole 142 are sequentially electrically connected to form induction coils respectively surrounding the magnetic core 30.

[0098] The first circuit unit 50 includes an inner conductor 52, and stacked first circuit layer 51, first insulating layer 42, and first adhesive layer 43. The first adhesive layer 43 covers the inner circuit layer 20 and seals the opposite ends of the receiving hole 16. The inner conductor 52 penetrates the first insulating layer 42 and the first adhesive layer 43 to electrically connect the inner circuit layer 20 and the first circuit layer 51. The second circuit unit 60 includes an outer conductor 64, and stacked second circuit layer 61, second insulating layer 62, and second adhesive layer 63. The second adhesive layer 63 covers the first circuit layer 51. The outer conductor 64 penetrates the second insulating layer 62 and the second adhesive layer 63 to electrically connect the first circuit layer 51 and the second circuit layer 61, as well as to electrically connect two adjacent second circuit layers 61. The second circuit layer 61 has a plurality of solder pads 612. Thus, the first circuit layer 51 and the second circuit layer 61, after being electrically connected to the first through hole 141 and the second through hole 142 via the inner conductor 52 and the outer conductor 64, also form a plurality of induction coils surrounding the magnetic core 30. In this embodiment, the number of the second circuit unit 60 is three, that is, the number of induction coils is five.

[0099] In some embodiments, there is a gap 161 between the magnetic core 30 and the receiving hole 16, and a fixing adhesive layer 302 is provided in the gap, so that the magnetic core 30 can be firmly fixed in the core layer 11 by the fixing adhesive layer 302 and the first adhesive layer 43.

[0100] Please refer to the following: Figure 5 Each receiving hole 16 includes a plurality of spaced sub-holes 162, which are connected end-to-end to form a generally U-shaped receiving hole 16. Two receiving holes 16 are arranged opposite each other. The magnetic core 30 is a non-closed U-shaped magnetic core, and the shape of the magnetic core 30 is adapted to the shape of the receiving hole 16. Each magnetic core 30 includes a plurality of sub-cores 301, and each sub-core 301 is placed in a corresponding sub-hole 162, thereby forming an air gap 34 between every two sub-cores 301 and at the connection between two magnetic cores 30. In this embodiment, the width of each air gap 34 is 0.2mm ± 20μm.

[0101] In some embodiments, the circuit board structure 100 further includes a solder resist layer 70 covering the outermost second circuit layer 61, the solder resist layer 70 having a plurality of openings 72 through which a plurality of solder pads 612 are exposed.

[0102] Compared with the prior art, the circuit board structure 100 provided in this application has the following advantages:

[0103] (i) By creating receiving holes 16 in the core layer 11, embedding the magnetic core 30, and then adding layers to form a multi-layer circuit layer, the winding frame can be eliminated, while increasing the heat dissipation area and improving power utilization. Furthermore, the current transmission path can be shortened, reducing the impact of parasitic inductance during high-frequency operation.

[0104] (ii) By setting multiple sub-holes 162 in the receiving hole 16, multiple segments of the sub-magnetic core 301 are respectively placed to form multiple air gaps 34. By utilizing the high precision characteristics of PCB processing technology, the processing method of multiple segments of the transformer magnetic core can be realized, and the size and number of air gaps 34 can be precisely controlled, thereby reducing the length of each segment of air gap 34, thereby reducing magnetic field leakage and reducing energy loss.

[0105] (III) By adding a first circuit layer 51 and multiple second circuit layers 61 and combining them with advanced blind via filling electroplating technology, multiple external conductive bodies 64 are formed, enabling a current density of up to 20A / mm². 2 This enables high power output. Furthermore, the multi-layered circuitry surrounding the magnetic core 30 provides a series-parallel structure, reducing losses during high current transmission and providing heat dissipation for the magnetic core 30.

[0106] Please see Figure 9 This application also provides a power supply device 1000 that uses the above-described circuit board structure 100. The circuit board structure 100 can be used as a DC-DC transformer module in power supply devices such as server power supplies, new energy vehicles, communication base stations, robots, drones, mobile phones, and power supply modules.

[0107] like Figure 9 As shown, the power supply device 1000 includes a circuit board structure 100, a main board 210, a chip 220, and multiple compensation components 230. The circuit board structure 100 and the chip 220 are respectively soldered to opposite sides of the main board 210. The compensation components 230 can be disposed on the side of the circuit board structure 100 opposite to the main board 210. By directly placing the circuit board structure 100 on the back of the chip 220, the shortest current transmission path can be achieved, resulting in low current loss.

[0108] The motherboard 210 is soldered to the solder pads 612 on one side, and has multiple solder pads 212 on the other side. The chip 220 is soldered to the solder pads 212 using multiple solder pastes 222. The chip 220 can be a CPU or GPU chip, and the compensation component 230 can be a resistor or capacitor, etc.

[0109] Please refer to the following: Figure 10 and Figure 11In the power supply device 1000, a first horizontal direction X and a second horizontal direction Y that are perpendicular to each other are defined. For one chip 220, 4 to 16 circuit board structures 100 can be set. The dense arrangement of multiple circuit board structures 100 can realize efficient current transformation and transmission.

[0110] Please see Figure 20 The second embodiment of this application also provides a circuit board structure 200, which is substantially the same as the circuit board structure 100, except that the circuit board structure 200 does not include the inner circuit layer 20, the inner conductor 52, the first insulating layer 42 and the second insulating layer 62.

[0111] Specifically, the circuit board structure 200 includes a core layer 11a, two magnetic cores 30a, and a first circuit unit 50a and a plurality of second circuit units 60a sequentially stacked on opposite sides of the core layer 11a along the thickness direction Z. The first circuit unit 50a includes a first adhesive layer 43a and a first circuit layer 51a stacked together. The core layer 11a has two receiving holes 16a through it, and each magnetic core 30a is disposed in one of the receiving holes 16a. A first through hole 141a and a second through hole 142a are provided through the first circuit unit 50a and the core layer 11a. The first through hole 141a is disposed on the side of the two receiving holes 16a away from the second through hole 142a, and the second through hole 142a is disposed between the two receiving holes 16a. The first through-hole 141a and the second through-hole 142a are both electrically connected to the two first line layers 51a, so that the two first line layers 51a, the first through-hole 141a and the second through-hole 142a are sequentially electrically connected to form an induction coil that winds around the magnetic core 30a.

[0112] The second circuit unit 60a includes an outer conductor 64a and a stacked second circuit layer 61a and a second adhesive layer 63a. The second adhesive layer 63a covers the first circuit layer 51a. The outer conductor 64a penetrates the second adhesive layer 63a to electrically connect the first circuit layer 51a and the second circuit layer 61a, as well as to electrically connect two adjacent second circuit layers 61a, thereby forming multiple induction coils wound around the magnetic core 30a. In this embodiment, the number of second circuit units 60a is three, that is, the number of induction coils is four.

[0113] Please see Figures 12 to 20 The second embodiment of this application also provides a method for manufacturing the above-described circuit board structure 200, comprising the following steps:

[0114] Step S21, please refer to Figure 12 and 13A core layer 11a is provided, the core layer 11a having a thickness direction Z, and two receiving holes 16a are formed through the core layer 11a along the thickness direction Z.

[0115] The two receiving holes 16a are spaced apart. In this embodiment, the core layer 11 is made of FR4 material.

[0116] Step S22, please refer to Figure 14 A release film 18 is provided on one side of the core layer 11a, and the release film 18 seals one end of the receiving hole 16a.

[0117] Step S23, please refer to Figure 15 The two magnetic cores 30a are respectively placed into one of the receiving holes 16a.

[0118] One end of the magnetic core 30a contacts the release film 18, and there is a gap 161a between the first magnetic core 30a and the second magnetic core 32a and the receiving hole 16a.

[0119] For step S24, please refer to... Figure 16 and Figure 17 A fixing adhesive layer 302a is respectively provided in the two gaps 161a, and the release film 18 is removed.

[0120] Step S25, please refer to Figure 18 An enhancement unit 40a is provided on each of the opposite sides of the core layer 11a. The enhancement unit 40a includes a stacked copper foil layer 41a and a first adhesive layer 43a.

[0121] Step S26, please refer to Figure 19 A plurality of first through holes 141a and a plurality of second through holes 142a are provided through the layering unit 40a and the core layer 11a along the thickness direction Z, and the copper foil layer 41a is patterned to form a first circuit layer 51a. The first circuit layer 51a and the first adhesive layer 43a together form a first circuit unit 50a, thereby obtaining an intermediate body 55a.

[0122] The first through-hole 141a is disposed around the two receiving holes 16a, and the second through-hole 142a is disposed between the two receiving holes 16a. The first through-hole 141a and the second through-hole 142a are both electrically connected to the two first circuit layers 51a, thereby the two first circuit layers 51a, the first through-hole 141a and the second through-hole 142a are sequentially electrically connected to form an induction coil wound around the magnetic core 30a.

[0123] Step S27, please refer to Figure 20Multiple second circuit units 60a are formed by adding layers on both sides of the intermediate body 55a to obtain a circuit board structure 200.

[0124] The second circuit unit 60a includes an outer conductor 64a and a stacked second circuit layer 61a and a second adhesive layer 63a. The second adhesive layer 63a covers the first circuit layer 51a. The outer conductor 64a penetrates the second adhesive layer 63a to electrically connect the first circuit layer 51a and the second circuit layer 61a, as well as to electrically connect two adjacent second circuit layers 61a, thereby forming multiple induction coils wound around the magnetic core 30a. In this embodiment, the number of second circuit units 60a is three, that is, the number of induction coils is four.

[0125] The above description is merely a few specific implementation methods of this application with optimizations, but in actual applications, it is not appropriate to be limited to these implementation methods. For those skilled in the art, other modifications and alterations made based on the technical concept of this application should fall within the protection scope of this application.

Claims

1. A circuit board structure, characterized in that, The device includes two magnetic cores, a core layer, and a first circuit unit and multiple second circuit units stacked sequentially on opposite sides of the core layer. The core layer has multiple first through-holes, second through-holes, and two receiving holes. A single receiving hole is U-shaped, and two receiving holes arranged opposite each other are O-shaped. The second through-hole is located between the two receiving holes. The first through-hole is located on the side of the two receiving holes away from the second through-hole. Each magnetic core is disposed within one of the receiving holes. Each receiving hole includes multiple spaced sub-holes, with a gap between two receiving holes and between every two sub-holes. Each magnetic core includes multiple sub-cores. A magnetic core is disposed in one of the sub-holes, and an air gap is formed between the two sub-cores and between the two cores respectively; the first circuit unit includes a first circuit layer, the second circuit unit includes a second circuit layer and an outer conductor, the first and second through holes are electrically connected to the first circuit layer, the outer conductor is electrically connected to the first circuit layer and the second circuit layer and electrically connected to two adjacent second circuit layers; the magnetic core is a U-shaped magnetic core, the magnetic core includes a body portion and protrusions connected to both ends of the body portion, the protrusions of the two magnetic cores are arranged opposite each other and form the air gap; the shape of the receiving hole is adapted to the shape of the magnetic core.

2. The circuit board structure as described in claim 1, characterized in that, The circuit board structure also includes two inner circuit layers disposed on opposite sides of the core layer, and the first via and the second via are electrically connected to the two inner circuit layers; The first circuit unit includes an inner conductor, and a first circuit layer, a first insulating layer and a first adhesive layer stacked thereon. The first adhesive layer covers the inner circuit layer, and the inner conductor penetrates the first insulating layer and the first adhesive layer to electrically connect the inner circuit layer and the first circuit layer. The second circuit unit further includes a second insulating layer and a second adhesive layer stacked together, and the outer conductor penetrates the second insulating layer and the second adhesive layer.

3. The circuit board structure as described in claim 2, characterized in that, The number of the second circuit unit is at least three, and the three second circuit units are stacked sequentially along the thickness direction; the thickness of the first insulating layer and the second insulating layer is 3 μm-7 μm; The thickness of the first and second circuit layers is greater than or equal to 70 μm, and the thickness of the circuit board structure is less than or equal to 2 mm.

4. The circuit board structure as described in claim 1, characterized in that, The first circuit unit includes a first circuit layer and a first adhesive layer stacked together, with the first adhesive layer facing the core layer; The first and second vias also penetrate the first adhesive layer, thereby electrically connecting the two first circuit layers; The second circuit unit further includes a second adhesive layer stacked on one side of the second circuit layer, and the outer conductor penetrates the second adhesive layer.

5. A method for manufacturing a circuit board structure, characterized in that, Including the following steps: A copper-clad substrate is provided, the copper-clad substrate including a core layer and inner circuit layers disposed on opposite sides of the core layer, a plurality of first vias, a second vias and two spaced-apart receiving holes are disposed through the copper-clad substrate, each receiving hole is U-shaped and the two receiving holes are O-shaped when disposed opposite each other; the second vias are located between the two receiving holes, and the first vias are disposed on the side of the two receiving holes away from the second vias, and both the first vias and the second vias are electrically connected to the two inner circuit layers; An add-in unit is provided on one side of the copper-clad substrate. The add-in unit includes a stacked copper foil layer, a first insulating layer, and a first adhesive layer. The first adhesive layer seals one end of the receiving hole. A magnetic core is provided in each of the two receiving holes. The receiving hole includes multiple spaced sub-holes. A gap is provided between the two receiving holes and between every two sub-holes. Each magnetic core includes multiple sub-cores. Each sub-core is correspondingly disposed in one of the sub-holes. An air gap is formed between the two sub-cores and between the two magnetic cores. The magnetic core is a U-shaped magnetic core. The magnetic core includes a body portion and protrusions connected to both ends of the body portion. The protrusions of the two magnetic cores are arranged opposite each other and form the air gap. The shape of the receiving hole is adapted to the shape of the magnetic core. Another layering unit is provided on the other side of the copper-clad substrate. Multiple inner conductors are formed through the layering unit, and the copper foil layer is patterned to form a first circuit layer. The first circuit layer, the first insulating layer, the first adhesive layer, and the inner conductors together form a first circuit unit. The inner conductors are electrically connected to the first circuit layer and the inner circuit layer to obtain an intermediate body. Multiple second circuit units are stacked on opposite sides of the intermediate body. Each second circuit unit includes an outer conductor, a stacked second circuit layer, a second insulating layer, and a second adhesive layer. The second adhesive layer covers the first circuit layer. The outer conductor penetrates the second insulating layer and the second adhesive layer to electrically connect the first circuit layer and the second circuit layer, as well as to electrically connect two adjacent second circuit layers, thereby obtaining a circuit board structure.

6. A method for manufacturing a circuit board structure, characterized in that, Including the following steps: A core layer is provided, through which two spaced-apart receiving holes are formed. Each receiving hole is U-shaped, and the two receiving holes are arranged opposite each other to form an O-shape. A magnetic core is disposed within each of the aforementioned receiving holes. Each receiving hole includes multiple spaced sub-holes, with a gap between two receiving holes and between every two sub-holes. The shape of the receiving hole is adapted to the shape of the magnetic core. Each magnetic core includes multiple sub-cores, each sub-core being disposed within a corresponding sub-hole. An air gap is formed between two sub-cores and between two magnetic cores. An enhancement unit is disposed on each of the opposite sides of the core layer. Each enhancement unit includes a stacked copper foil layer and a first adhesive layer, with the first adhesive layer facing the core layer. The magnetic core is a U-shaped magnetic core, comprising a body portion and protrusions connected to both ends of the body portion. The protrusions of two magnetic cores are disposed opposite each other and form the air gap. The shape of the receiving hole is adapted to the shape of the magnetic core. A first through-hole and a second through-hole are formed through the added-layer unit and the core layer, and each copper foil layer is patterned to form a first circuit layer. The first through-hole is disposed around the two receiving holes, and the second through-hole is disposed between the two receiving holes. The first through-hole and the second through-hole are electrically connected to the two first circuit layers to obtain an intermediate body. Multiple second circuit units are stacked on opposite sides of the intermediate body. Each second circuit unit includes an outer conductor, a stacked second circuit layer, and a second adhesive layer. The second adhesive layer covers the first circuit layer. The outer conductor penetrates the second adhesive layer to electrically connect the first circuit layer and the second circuit layer, as well as to electrically connect two adjacent second circuit layers, thereby obtaining a circuit board structure.

7. A power supply device, characterized in that, It includes a chip, a motherboard, and a circuit board structure as described in any one of claims 1 to 4, wherein the circuit board structure and the chip are respectively soldered to opposite sides of the motherboard.

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