Circuit board with built-in conductor

Abstract

This circuit board with built-in conductor includes: a base material having a first surface, a second surface located on a side opposite to the first surface in a thickness direction, and a through hole extending in the thickness direction; a first wiring layer disposed on the first surface of the base material; a second wiring layer disposed on the second surface of the base material; and a first conductor and a second conductor that are disposed in the through hole and extend in the thickness direction, respectively, and in the through hole, further includes a separation insulating layer that is located between the first conductor and the second conductor in a plan view viewed along the thickness direction and separates the first conductor and the second conductor.

Description

Conductor-embedded circuit board

[0001] The present invention relates to a circuit board with built-in conductors.

[0002] Voltage regulation modules are used to supply power to processing units such as CPUs, GPUs, etc. A known voltage regulation module is a step-down switching regulator module that combines functional components such as switch elements, inductors, and capacitors.

[0003] Such a voltage regulation module is usually arranged in parallel with the arithmetic processing unit on one main surface of a system board (motherboard). However, it has also been proposed to arrange the voltage regulation module on the main surface of the system board opposite to the main surface on which the arithmetic processing unit is arranged (see Patent Document 1).

[0004] Patent Document 1 discloses a voltage regulation module with a three-layer structure in which a magnetic core assembly is disposed between two circuit board assemblies. The magnetic core assembly contains a conductor that constitutes an inductor.

[0005] US Patent Application Publication No. 2020 / 0111597

[0006] The voltage regulation module of Patent Document 1 has room for improvement in terms of making the structure containing the conductor smaller.

[0007] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a circuit board with built-in conductors that can be made smaller in size in order to solve the above problems.

[0008] The circuit board with built-in conductors of the present disclosure comprises: a substrate having a first surface, a second surface located on the opposite side of the first surface in the thickness direction from the first surface, and a through hole extending in the thickness direction; a first wiring layer arranged on the first surface of the substrate; a second wiring layer arranged on the second surface of the substrate; and a first conductor and a second conductor arranged in the through hole, each extending in the thickness direction, and further comprising an isolation insulating layer located in the through hole between the first conductor and the second conductor in a planar view seen along the thickness direction, and separating the first conductor from the second conductor.

[0009] According to the present invention, a circuit board with built-in conductors is provided that can be made smaller.

[0010] 1 is a schematic perspective view of a circuit board with built-in inductor according to a first embodiment. It is a schematic exploded perspective view of the circuit board with built-in inductor of FIG. 1. It is a schematic top view showing a component-embedded substrate and some wiring layers in the circuit board with built-in inductor of FIG. 1. It is a schematic bottom view showing a component-embedded substrate and some wiring layers of FIG. 3A. It is a schematic cross-sectional view taken along line IIIC-IIIC in FIGS. 3A and 3B. It is a schematic perspective view of an inductor unit cell. It is a schematic top view of the inductor unit cell of FIG. 4. It is a schematic cross-sectional view taken along line VB-VB in FIG. 5A. It is a diagram showing a basic circuit configuration of a voltage regulation module (step-down converter). It is a schematic top view showing steps in a method for manufacturing an inductor unit cell. It is a schematic cross-sectional view taken along line VIIB-VIIB shown in FIG. 7A. It is a schematic top view showing steps in a method for manufacturing an inductor unit cell. It is a schematic cross-sectional view taken along line VIIIB-VIIIB shown in FIG. 8A. It is a schematic top view showing steps in a method for manufacturing an inductor unit cell. 9A , 9B, 9C, 9D, 9E, 9F, 9G, 9H ... 16A , 17A , 17B , 17C , 17D , 17E , 17F , 17G , 17H , 17I , 17J , 17JI ...18A , 19A , 20A , 21A , 22A , 23A , 24A , 25A , 26A , 27A , 28A , 29A , 30A , 31A , 32A , 33A , 34A , 35A , 36A , 37A , 38A , 39A , 40A , 41A , 42A , 43A , 44A , 45A , 46A , 47A , 48A , 49A , 50A , 51A , 52A , 53A , 54A , 55A , 56A , 57A , 58A , 59A , 60A , 61A , 62A , 63A , 64A , 65A , 66A , 67A , 68A , 69A , 70A , 71A , 72A , 73A , 74A , 75A , 76A , 77A , 78A , 79A ,80A , 81A , 82A , 83A , 84A , 85A , 86A , 87A , 88A , 90A , 90A , 91A , 92A , 93A , 94A , 95A , 96A , 97A , 98A , 99A ,00A ,01A ,02A ,03A , 23A , 24A , 25B , 26A , 27A , 28A , 29A , 30B , 31B , 32B , 33B , 34B , 35B , 36B , 37B , 38B , 39B , 40B , 41B , 42B , 43B , 44B , 45B , 46B , 47B , 48B , 49B , 50B , 51B , 52B , 53B , 54B , 55B , 56B , 57B , 58B , 59B , 60B , 61B , 62B , 63B , 64B , 65B , 66B , 67B , 68B , 69B , 70B , 71B , 72B , 73B , 74B , 75B , 76B , 77B , 78B , 79B , 80B , 81B , 82B , 83B , 84B , 85B , 86B , 87B , 88B , 89B , 90B , 91B , 92B , 93B , 94B , 95B , 96B , 97B , 98B , 99B , 100B , 101B , 102B , 103B , 104B , 105B , 106B , 28A. It is a schematic cross-sectional view of the process taken along the line XXVIIIB-XXVIIIB shown in Figure 28A. It is a schematic top view of the process showing the manufacturing method of the circuit board. It is a schematic cross-sectional view of the process taken along the line XXIXB-XXIXB shown in Figure 29A. It is a schematic perspective view of the conductor-containing portion in the circuit board of the third embodiment. It is a schematic top view of the conductor-containing portion of Figure 30.31B is a schematic cross-sectional view taken along line XXXIB-XXXIB in FIG. 31A. FIG. 31B is a schematic top view of Modification 1 of the conductor-containing portion. FIG. 32A is a schematic cross-sectional view taken along line XXXIIB-XXXIIB in FIG. 32A. FIG. 32B is a schematic top view of Modification 2 of the conductor-containing portion. FIG. 33A is a schematic cross-sectional view taken along line XXXIIIB-XXXIIIB in FIG. 33A. FIG. 33B is a schematic top view of Modification 3 of the conductor-containing portion. FIG. 34A is a schematic cross-sectional view taken along line XXXIVB-XXXIVB in FIG. 34A. FIG. 34A is a schematic top view of Modification 4 of the conductor-containing portion. FIG. 35A is a schematic cross-sectional view taken along line XXXVB-XXXVB in FIG. 35A. FIG. 36A is a schematic top view of Modification 5 of the conductor-containing portion. FIG. 36A is a schematic cross-sectional view taken along line XXXVIB-XXXVIB in FIG. 36A. FIG. 36B is a schematic top perspective view of the conductor-containing portion and the second electrode of configuration example (2). 38B is a diagram illustrating an example of a circuit configuration of a voltage regulation module using the circuit board of configuration example (2). FIG. 38C is a diagram illustrating a simplified version of the circuit configuration shown in FIG. 38A. FIG. 38D is a diagram illustrating phase 1 of the circuit shown in FIG. 38B. FIG. 38C is a diagram illustrating a waveform of a ripple current of the circuit shown in FIG. 38A. FIG. 38D is a diagram illustrating a schematic top perspective view of a conductor-containing portion and a second electrode of configuration example (3). FIG. 38C is a diagram illustrating an example of a circuit configuration of a voltage regulation module using the circuit board of configuration example (3). FIG. 38D is a diagram illustrating a schematic top perspective view of a conductor-containing portion and a second electrode of configuration example (5). FIG. 38D is a diagram illustrating a schematic bottom perspective view of a conductor-containing portion and a first electrode of configuration example (5). FIG. 38E is a diagram illustrating an example of a circuit configuration of a voltage regulation module using the circuit board of configuration example (3). FIG. 38F is a diagram illustrating a schematic top perspective view of a conductor-containing portion and a second electrode of configuration example (5). FIG. 38F is a diagram illustrating a schematic bottom perspective view of a conductor-containing portion and a first electrode of configuration example (5). FIG. 38F is a diagram illustrating a schematic perspective view of a process of manufacturing a first structure M. 10A to 10C are schematic perspective views illustrating the steps of a method for manufacturing the first structure M. FIG. 10B are schematic perspective views illustrating the steps of a method for manufacturing the first structure M. FIG. 10C are schematic perspective views illustrating the steps of a method for manufacturing a conductor-containing portion. FIG. 10D are schematic perspective views illustrating the steps of a method for manufacturing the first structure M. FIG. 10E are schematic top views for explaining an example of a method for designing the first structure M. FIG. 10F are schematic cross-sectional views illustrating a voltage regulation module of a fourth embodiment.FIG. 10 is a schematic cross-sectional view showing an inductor-embedded assembly according to a reference example.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to these embodiments. In addition, substantially identical components in the drawings are designated by the same reference numerals. For illustrative purposes, the dimensions of each element in the drawings may be exaggerated and are not necessarily drawn to scale.

[0012] Hereinafter, a board with a built-in conductor will be referred to as a "circuit board with built-in conductor." Among circuit boards with built-in conductors, those in which multiple built-in conductors are connected in series to form an inductor may be called a "circuit board with built-in inductor." Circuit boards with built-in conductors or circuit boards with built-in inductors may be abbreviated to "circuit board."

[0013] Furthermore, for the sake of convenience, terms indicating directions such as "up," "down," "right," "left," and "side" are used below assuming a state during normal use, but are not intended to limit the state of use of the circuit board according to the present disclosure. Furthermore, in this specification, "orthogonal" means within a range of 90°±10°. "Parallel" means, for example, within a range of ±5°. Furthermore, while shapes, directions (orientations), etc. may be described below, this does not only include the described shapes and directions, but also includes cases where the shapes and directions are roughly the same. For example, "rectangular prism" includes not only rectangular prisms but also cases where the shapes are approximately rectangular prisms.

[0014] In the drawings described below, for reference, mutually orthogonal X-axis, Y-axis, and Z-axis are schematically shown. The Z-axis corresponds to the thickness direction of the circuit board. In the following description, when the X-direction, Y-direction, or Z-direction is simply mentioned, it refers to the respective axial direction, and includes two opposite directions (for example, the −X-direction and the +X-direction).

[0015] First Embodiment (Foundational Findings) The present inventors have conducted extensive research into the configuration of a circuit board with a built-in inductor that can make the voltage regulation module thinner. As a result, they have made the following findings.

[0016] The rapid increase in data traffic in information and communications has led to an increase in the current required by processing units used in data centers, etc. As the current increases, it becomes necessary to suppress the transient voltage response (voltage fluctuation) of the processing unit in response to current fluctuations (load fluctuations).

[0017] By arranging the voltage regulation module on the main surface of the system board opposite to the main surface on which the arithmetic processing unit is arranged (hereinafter referred to as the "opposite surface"), the output terminal of the voltage regulation module and the input terminal of the arithmetic processing unit can be arranged close to each other, which makes it possible to more effectively suppress voltage transient responses.

[0018] The voltage regulator module disposed on the opposing surface is required to incorporate functional components such as an inductor and to be thinner.

[0019] However, as mentioned above, it may be difficult to reduce the thickness of the voltage regulation module disclosed in Patent Document 1. In Patent Document 1, an inductor is formed by arranging a conductor that penetrates the magnetic core in the thickness direction of the magnetic core assembly (see FIG. 46). With this structure, the thickness of the magnetic core assembly is limited by the height of the conductor within the magnetic core. Furthermore, two separate circuit board assemblies are required above and below the magnetic core assembly. Therefore, the thickness of the module is further increased by the thickness of the two circuit board assemblies and the soldered connections between the assemblies.

[0020] Therefore, the inventors have newly discovered that by dividing the inductor into multiple parts and incorporating them into a circuit board, the thickness of the circuit board with an inductor built in can be reduced, and that using such a circuit board with an inductor built in can make the voltage regulation module thinner. Based on this new discovery, the inventors have arrived at the following embodiment.

[0021] [Overall Configuration of Circuit Board with Built-in Inductor] First, an overview of a circuit board with built-in inductor (hereinafter, "circuit board") according to a first embodiment of the present disclosure will be described with reference to FIGS.

[0022] Fig. 1 is a schematic perspective view of a circuit board according to an embodiment of the present disclosure, and Fig. 2 is a schematic exploded perspective view of the circuit board of Fig. 1.

[0023] 1, the circuit board 1 has, for example, a substantially rectangular parallelepiped shape. The circuit board 1 has a first main surface s1 and a second main surface s2 located on the opposite side of the first main surface s1 in the thickness direction (Z direction). In each drawing, for convenience, the thickness direction of the circuit board 1 is defined as the Z direction, the direction parallel to the long sides of the main surfaces s1 and s2 of the circuit board 1 is defined as the X direction, and the direction parallel to the short sides is defined as the Y direction.

[0024] 2 , the circuit board 1 includes a first wiring structure 100, a second wiring structure 200, and a component-embedded substrate 300. In the thickness direction (Z direction) of the circuit board 1, the component-embedded substrate 300 is located between the first wiring structure 100 and the second wiring structure 200. In this example, the first wiring structure 100 is located on the first main surface s1 side of the component-embedded substrate 300, and the second wiring structure 200 is located on the second main surface s2 side of the component-embedded substrate 300.

[0025] The component-embedded substrate 300 includes a substrate 10 (also referred to as a "core substrate") and components such as an inductor 2 and a two-terminal capacitor disposed inside the substrate 10. In this specification, components disposed (embedded) inside the substrate 10 may be collectively referred to as "embedded components."

[0026] The substrate 10 has, for example, a substantially rectangular parallelepiped shape. The substrate 10 has a first surface (here, a bottom surface) 11 and a second surface (here, a top surface) 12 located on the opposite side of the first surface 11 in the Z direction. The first surface 11 is located on the first main surface s1 side of the circuit board 1, and the second surface 12 is located on the second main surface s2 side of the circuit board 1.

[0027] Built-in components such as the inductor 2 and the two-terminal capacitor are disposed in through holes provided in the substrate 10 .

[0028] The first wiring structure 100 is located on the first surface 11 of the substrate 10. The first wiring structure 100 has a layered structure in which multiple (three in this case) insulating layers 101 to 103 and multiple wiring layers 110 to 130 are alternately stacked in the thickness direction (-Z direction). Here, from the substrate 10 side, the insulating layer 101, the wiring layer 110, the insulating layer 102, the wiring layer 120, the insulating layer 103, and the wiring layer 130 are stacked in this order.

[0029] The second wiring structure 200 is located on the second surface 12 of the base material 10. The second wiring structure 200 has a layered structure in which multiple (three layers in this case) insulating layers 201-203 and multiple wiring layers 210-230 are alternately stacked in the thickness direction (+Z direction). Here, from the base material 10 side, the insulating layer 201, the wiring layer 210, the insulating layer 202, the wiring layer 220, the insulating layer 203, and the wiring layer 230 are stacked in this order.

[0030] Each of the wiring layers 110 to 130, 210 to 230 has electrodes, wiring, terminal portions, etc. A plurality of via conductors v are arranged in each of the insulating layers 101 to 103, 201 to 203 to electrically connect the electrodes located above and below each other.

[0031] The circuit board 1 may further include solder resist layers 105, 205. The solder resist layer 105 is disposed on the first main surface s1 side of the first wiring structure 100. The solder resist layer 205 is disposed on the second main surface s2 side of the second wiring structure 200. The solder resist layers 105, 205 are provided to suppress solder flow when components and BGAs (Ball Grid Arrays) are mounted on the circuit board 1 by soldering.

[0032] [Component-Embedded Substrate] The structure of the component-embedded substrate 300 will be described in more detail below with reference to FIGS. 3A to 3C. FIGS. 3A and 3B are schematic top and bottom views, respectively, showing the component-embedded substrate and some of the wiring layers. FIG. 3C is a schematic cross-sectional view taken along line IIIC-IIIC in FIGS. 3A and 3B. In addition to the component-embedded substrate 300, FIG. 3C also shows the wiring layer 110 of the first wiring structure 100 that is closest to the substrate 10, and the wiring layer 210 of the second wiring structure 200 that is closest to the substrate 10. For ease of understanding, electrodes in the wiring layers 210 and 110 are indicated by dashed two-dot lines in FIGS. 3A and 3B.

[0033] 3A to 3C, the component-embedded substrate 300 includes a substrate 10, an inductor 2, an input capacitor 5, an output capacitor 6, and a plurality of through-core conductors 7. The inductor 2 has three inductor unit cells 20a to 20c.

[0034] The inductor unit cells 20 a to 20 c, the input capacitor 5 , the output capacitor 6 and the through-core conductor 7 are located (embedded) inside the substrate 10 .

[0035] 3C, the inductor 2 includes a plurality of (three in this case) conductors 3a to 3c and a plurality of (three in this case) magnetic bodies 4a to 4c. Each of the conductors 3a to 3c extends in the Z direction to penetrate a corresponding one of the magnetic bodies 4a to 4c.

[0036] In this embodiment, the conductor 3a and the magnetic material 4a form one inductor unit cell 20a. Similarly, the conductor 3b and the magnetic material 4b form the inductor unit cell 20b, and the conductor 3c and the magnetic material 4c form the inductor unit cell 20c. The inductor unit cells 20a to 20c are connected in series to form one inductor. In this specification, when multiple inductors are connected in series to function as a single inductor, each of the multiple series-connected inductors is referred to as an "inductor unit cell." In other words, the three components described as inductor unit cells 20a to 20c can each function as an inductor on their own.

[0037] The conductors 3a to 3c are arranged at a distance from one another in the substrate 10 in a plan view along the Z direction (hereinafter sometimes simply referred to as "plan view"). Each of the conductors 3a to 3c extends in the Z direction. In the illustrated example, the conductors 3a to 3c are arranged in this order in the X direction in a plan view.

[0038] The magnetic body 4a is located around the conductor 3a so as to surround the peripheral surface of the conductor 3a. Similarly, the magnetic bodies 4b and 4c are located around the conductors 3b and 3c so as to surround the peripheral surfaces of the conductors 3b and 3c, respectively. Two adjacent magnetic bodies among the magnetic bodies 4a to 4c are separated from each other by a partition wall of the substrate 10.

[0039] In the illustrated example, the ends (first ends) of the conductors 3a and 3b on the first surface 11 side are electrically connected to each other by a first connection electrode 111 in the wiring layer 110. Furthermore, the ends (second ends) of the conductors 3b and 3c on the second surface 12 side are electrically connected to each other by a second connection electrode 212 in the wiring layer 210. As a result, the conductors 3a to 3c are connected in series.

[0040] In this embodiment, the inductor unit cells 20a to 20c are connected in series by the first and second connection electrodes 111, 212 to form the inductor 2. By dividing the inductor into three or more (three in this case) inductor unit cells 20a to 20c and arranging them within the substrate 10, it is possible to reduce the thickness of the substrate 10 required to arrange the inductor 2 while ensuring a desired inductance value.

[0041] The substrate 10 of the component-embedded substrate 300 and each of the built-in components will be described in more detail below.

[0042] 3C , the substrate 10 has an inductor arrangement region r1 in which the inductor 2 is arranged, a capacitor arrangement region r2 in which the capacitors 5 and 6 are arranged, and a through-core conductor arrangement region r3 in which a plurality of through-core conductors 7 are arranged. In this example, the inductor arrangement region r1, the capacitor arrangement region r2, and the through-core conductor arrangement region r3 are arranged in this order in the X direction.

[0043] In the inductor arrangement region r1, the substrate 10 is provided with through holes 13a to 13c that penetrate from the first surface 11 to the second surface 12. Each of the through holes 13a to 13c is, for example, a rectangular prism-shaped opening. In the example shown, the through holes 13a to 13c are aligned in the X direction, and two adjacent through holes are separated by a partition wall of the substrate 10. Inductor unit cells 20a to 20c are arranged in the through holes 13a to 13c, respectively.

[0044] In the capacitor arrangement region r2, the substrate 10 is provided with two through holes 14, 15 that penetrate from the first surface 11 to the second surface 12. Each of the through holes 14, 15 is, for example, a rectangular prism-shaped opening. In the example shown, the through holes 14, 15 are arranged side by side in the Y direction and are separated from each other by a partition wall of the substrate 10. An input capacitor 5 is arranged in the through hole 14, and an output capacitor 6 is arranged in the through hole 15.

[0045] In the through-core conductor arrangement region r3, a plurality of through holes 16 are provided in the substrate 10. In the example shown, fifteen cylindrical through holes 16 are arranged in a matrix in the X and Y directions. A through-core conductor 7 is arranged in each through hole 16. Each of the through-core conductors 7 can function as a connection conductor for electrically connecting a circuit in the first wiring structure 100 and a circuit in the second wiring structure 200.

[0046] (Inductor Unit Cells 20a to 20c) The detailed structure of the inductor unit cells will be described with reference to FIGS. 4 to 5B. FIG. 4 is a schematic perspective view of an inductor unit cell. FIG. 5A is a schematic top view of the inductor unit cell of FIG. 4. FIG. 5B is a schematic cross-sectional view taken along line VB-VB in FIG. 5A. Here, the inductor unit cell 20a will be described as an example.

[0047] The inductor unit cell 20a includes a magnetic body 4a, a conductor 3a penetrating the magnetic body 4a, a first electrode 31a electrically connected to a first end of the conductor 3a, and a second electrode 32a electrically connected to a second end of the conductor 3a.

[0048] The magnetic body 4a has a shape corresponding to the through-hole of the substrate 10, for example, a quadrangular prism shape (here, a rectangular parallelepiped shape). The magnetic body 4a has a magnetic body through-hole 41 that penetrates in the thickness direction (Z direction). The magnetic body through-hole 41 is, for example, cylindrical. In a plan view, the magnetic body through-hole 41 is located approximately in the center of the magnetic body 4a.

[0049] The conductor 3a is disposed inside the magnetic body through hole 41 and extends in the Z direction. The conductor 3a has a shape corresponding to the shape of the magnetic body through hole 41. Here, the conductor 3a is a cylindrical body having a first end face e1, a second end face e2, and a peripheral surface 3s located between these end faces e1 and e2. The peripheral surface 3s of the conductor 3a is surrounded by the magnetic body 4a. Each of the first end face e1 and the second end face e2 is at least partially exposed from the magnetic body 4a. The first end face e1 is a downward surface (facing in the −Z direction). The first end face e1 may be substantially flush with the bottom surface of the magnetic body 4a. The second end face e2 is an upward surface (facing in the +Z direction). The second end face e2 may be substantially flush with the top surface of the magnetic body 4a.

[0050] The inductor unit cell 20a may further include a resin member that seals the conductor 3a in the magnetic body through hole 41 of the magnetic body 4a. The resin member includes, for example, an insulating portion 23 that is arranged to fill the gap between the inner wall of the magnetic body through hole 41 and the conductor 3a. The resin member may cover the upper and lower surfaces of the magnetic body 4a.

[0051] The first electrode 31a is disposed on the first end surface e1 of the conductor 3a, with the first cell insulating portion 21 sandwiched therebetween. The first electrode 31a is electrically connected to a first end of the conductor 3a through at least one (here, multiple) via conductors 33 disposed in the first cell insulating portion 21. In the illustrated example, one end of the via conductor 33 is connected to the first electrode 31a, and the other end is connected to the first end surface e1 of the conductor 3a.

[0052] The second electrode 32a is disposed on the second end surface e2 of the conductor 3a, with the second cell insulating portion 22 sandwiched therebetween. The second electrode 32a is electrically connected to the second end of the conductor 3a through at least one (here, multiple) via conductors 34 disposed in the second cell insulating portion 22. In the illustrated example, one end of the via conductor 34 is connected to the second electrode 32a, and the other end is connected to the second end surface e2 of the conductor 3a.

[0053] The first cell insulating part 21 may include a portion of the resin member that covers the lower surface of the magnetic body 4 a (sealing insulating layer 24 shown in FIG. 10B ). Similarly, the second cell insulating part 22 may include a portion of the resin member that covers the upper surface of the magnetic body 4 a (sealing insulating layer 25 shown in FIG. 10B ).

[0054] In a plan view, the first electrode 31 a and the second electrode 32 a may have a larger area than the corresponding conductor 3 a. In the example shown, in a plan view, the first electrode 31 a overlaps the entire first end face e1 of the conductor 3 a and at least a portion of the magnetic body 4 a. The second electrode 32 a overlaps the entire second end face e2 of the conductor 3 a and at least a portion of the magnetic body 4 a.

[0055] The size of each rectangular parallelepiped magnetic body 4a is, for example, 2.3 mm (X direction) × 3 mm (Y direction) × 1.8 mm (Z direction). The diameter of the cylindrical magnetic body through-hole 41 is, for example, 1.1 mm. The diameter of each cylindrical conductor 3a is 1.0 mm and the thickness is 1.8 mm. The thickness of each of the first cell insulating portion 21 and the second cell insulating portion 22 is, for example, 30 μm.

[0056] In the illustrated example, the conductors 3a to 3c and the magnetic body through-hole 41 are cylindrical, but they may also be rectangular. Furthermore, the conductors 3a to 3c and the magnetic body through-hole 41 only need to extend from the top surface to the bottom surface of the magnetic body 4a, and do not have to be parallel to the Z direction.

[0057] 3A to 3C, the other inductor unit cells 20b and 20c, like the inductor unit cell 20a, include magnetic materials 4b and 4c, conductors 3b and 3c, first electrodes 31b and 31c, and second electrodes 32b and 32c. The inductor unit cells 20b and 20c also have a structure similar to that of the inductor unit cell 20a described above with reference to FIGS. 4 to 5B. In this embodiment, the inductor unit cells 20a to 20c have the same size, but may have different sizes.

[0058] 3C , the input capacitor 5 is a two-terminal capacitor including a lower electrode 51, an upper electrode 52, and a dielectric 53. The dielectric 53 is located between the lower electrode 51 and the upper electrode 52 in the Z direction. The lower electrode 51 is located on the first surface 11 side of the dielectric 53, and the upper electrode 52 is located on the second surface 12 side of the dielectric 53. The input capacitor 5 can function as a bypass capacitor for the input-side power line of the voltage regulation module.

[0059] Similarly, output capacitor 6 is a two-terminal capacitor including a lower electrode 61 (FIG. 3B), an upper electrode 62 (FIG. 3A), and a dielectric located between lower electrode 61 and upper electrode 62 in the Z direction. Lower electrode 61 is located on first surface 11 of the dielectric, and upper electrode 62 is located on second surface 12 of the dielectric. Output capacitor 6 can function as a bypass capacitor for the output power line of the voltage regulation module.

[0060] (Sealing Member 8) The component-embedded substrate 300 further includes a sealing member 8 that seals the substrate 10 in which the inductor unit cells 20a-20c, the input capacitor 5, the output capacitor 6, and the through-core conductor 7 are disposed. In the example shown in Fig. 3C, the sealing member 8 is disposed in the gap between the inner walls of the through holes 13a-13c, 14-16 and the components located in those through holes. The sealing member 8 may also be disposed on the first surface 11 of the substrate 10 and the second surface 12 of the substrate 10.

[0061] [Wiring Layers 110, 210] Next, the structures of the wiring layers 110, 210 arranged on the first surface 11 side and the second surface 12 side of the substrate 10 will be described with reference to FIGS. 3A to 3C.

[0062] The wiring layer 110 (sometimes referred to as the "first wiring layer") is disposed on the first surface 11 of the substrate 10 via a first insulating portion 91. The "first insulating portion" is an insulating portion located between the wiring layer 110 and the first surface 11 of the substrate 10. In this embodiment, the first insulating portion 91 includes a part of the sealing member 8 of the component-embedded substrate 300 (the lower insulating layer 81 shown in FIG. 17B ) and the insulating layer 101 ( FIG. 2 ) that is closest to the substrate 10 of the first wiring structure 100.

[0063] The wiring layer 210 (sometimes referred to as the "second wiring layer") is disposed on the second surface 12 of the substrate 10 via a second insulating portion 92. The "second insulating portion" is an insulating portion located between the wiring layer 210 and the second surface 12 of the substrate 10. In this embodiment, the second insulating portion 92 includes a part of the sealing member 8 of the component-embedded substrate 300 (upper insulating layer 82 shown in FIG. 17B ) and the insulating layer 201 ( FIG. 2 ) that is closest to the substrate 10 of the second wiring structure 200.

[0064] A plurality of via conductors are formed in the first insulating portion 91 to electrically connect each component in the substrate 10 to an electrode in the wiring layer 110. Similarly, a plurality of via conductors are formed in the second insulating portion 92 to electrically connect each component in the substrate 10 to an electrode in the wiring layer 210. One or more via conductors may be arranged for one electrode of an embedded component. In order to increase the connection area, it is preferable to arrange multiple via conductors for one electrode.

[0065] 3B and 3C, the wiring layer 110 has a first connection electrode 111, a first inductor connection electrode 112 connected to the output end of the inductor, and a first input capacitor connection electrode 113. These electrodes 111 to 113 are arranged at a distance from each other.

[0066] The first connection electrode 111 electrically connects the ends (first ends) of the conductors 3 a and 3 b on the first surface 11 side. In the example shown, the first connection electrode 111 is electrically connected to the first electrode 31 a of the inductor unit cell 20 a and the first electrode 31 b of the inductor unit cell 20 b through via conductors in the first insulating part 91.

[0067] The first connection electrode 111 has, for example, a rectangular planar shape. In plan view, the first connection electrode 111 may overlap the entire conductors 3a and 3b, preferably the entire first electrodes 31a and 31b.

[0068] The first inductor connection electrode 112 electrically connects the first end of the conductor 3c, which is the output end of the inductor 2, to the lower electrode 61 of the output capacitor 6. In the example shown, the first inductor connection electrode 112 is electrically connected to the first electrode 31c of the inductor unit cell 20c and the lower electrode 61 of the output capacitor 6 through a via conductor in the first insulating part 91.

[0069] The first input capacitor connection electrode 113 is electrically connected to the lower electrode 51 of the input capacitor 5 and some of the through-core conductors 7 through via conductors in the first insulating portion 91 .

[0070] 3A and 3C, the wiring layer 210 has a second inductor connection electrode 211 connected to the input end of the inductor, a second connection electrode 212, a second input capacitor connection electrode 213, and an output capacitor connection electrode 214. These electrodes 211 to 214 are arranged at a distance from each other.

[0071] The second inductor connection electrode 211 is electrically connected to the second end of the conductor 3a, which is the input end of the inductor 2. In the example shown, the second inductor connection electrode 211 is electrically connected to the second electrode 32a of the inductor unit cell 20a through a via conductor in the second insulating part 92.

[0072] The second connection electrode 212 electrically connects the ends (second ends) of the conductors 3b and 3c on the second surface 12 side. In the illustrated example, the second connection electrode 212 is electrically connected to the second electrode 32b of the inductor unit cell 20b and the second electrode 32c of the inductor unit cell 20c through via conductors in the second insulating portion 92.

[0073] The second connection electrode 212 has, for example, a rectangular planar shape. In plan view, the second connection electrode 212 may overlap the entire conductors 3b and 3c, preferably the entire second electrodes 32b and 32c.

[0074] The second input capacitor connection electrode 213 is electrically connected to the upper electrode 52 of the input capacitor 5 and some of the through-core conductors 7 through via conductors in the second insulating portion 92. This allows the upper electrode 52 of the input capacitor 5 to be electrically connected to the input terminal Vin on the opposite side across the substrate 10 through the some of the through-core conductors 7.

[0075] The output capacitor connection electrode 214 is electrically connected to the upper electrode 62 of the output capacitor 6 and some of the through-core conductors 7 through the via conductors in the second insulating portion 92. This allows the upper electrode 62 of the output capacitor 6 to be electrically connected to the ground terminal GND on the opposite side across the substrate 10 through the some of the through-core conductors 7.

[0076] [Circuit Configuration of Voltage Regulation Module] The circuit configuration of the circuit board 1 of this embodiment will be described below, taking as an example a case where the circuit board 1 is applied to a step-down switching regulator (step-down converter).

[0077] 6 is a diagram showing the basic circuit configuration of a voltage regulation module (step-down converter), which includes a circuit board 1 according to this embodiment and a switch element SW.

[0078] The switch element SW includes MOSFETs 410 and 420, a switch input terminal SW_Vin, a switch output terminal SW_Vout, a switch GND terminal SW_GND, and a switch control terminal SW-CTL. Other switching elements may be used instead of the MOSFETs. The switch element SW is disposed on the first main surface of the circuit board 1, for example (see FIG. 45).

[0079] 6 are built into the circuit board 1. The control terminal CTL, input terminal Vin, output terminal Vout, and ground terminal GND are formed, for example, on the uppermost wiring layer 230 of the circuit board 1 (see FIG. 23A). Furthermore, terminal lands for each terminal of the switch element SW are formed on the lowermost wiring layer 130 of the circuit board 1 (see FIG. 23B).

[0080] 6, the high-side MOSFET 410 is connected to the input terminal Vin. The low-side MOSFET 420 is connected to the GND terminal side of the MOSFET 410. An input voltage is applied to the switch input terminal SW_Vin from the input terminal Vin.

[0081] The inductor 2 is configured by connecting inductor unit cells 20a to 20c in series in this order. The input terminal p2 of the inductor 2 is connected to the switch output terminal SW_Vout.

[0082] The input capacitor 5 is shunt-connected to the switch input terminal SW_Vin, with the upper electrode 52 of the input capacitor 5 connected to the switch input terminal SW_Vin and the lower electrode 51 connected to the ground terminal GND.

[0083] The output capacitor 6 is shunt-connected to the output terminal Vout, with the lower electrode 61 of the output capacitor 6 connected to the output terminal Vout and the upper electrode 62 connected to the ground terminal GND.

[0084] In this circuit, the pulse waveform generated by alternately turning on and off the MOSFETs 410 and 420 in the switch element SW is smoothed by the inductor 2 and the output capacitor 6. This generates a desired output voltage, which is then output from the output terminal Vout.

[0085] [Materials of Each Component] The magnetic materials for the magnetic bodies (magnetic base bodies) 4a-4c of the inductor unit cells 20a-20c may be any material with magnetic permeability, such as a metal magnetic body or a ferrite sintered body. The magnetic material is preferably a composite material of a metal magnetic powder and an organic material. This is because the magnetostriction of a metal magnetic body is smaller than that of a ferrite sintered body, so that the performance degradation of the metal magnetic body due to external stress when embedded in the substrate 10 is minimal. Furthermore, the composite form of a metal magnetic powder and an organic material improves DC bias characteristics and facilitates processing for forming through holes. Furthermore, the use of an organic material allows, for example, when embedded in the substrate 10, to elastically absorb external stress and reduce internal stress on the metal magnetic powder. This makes it possible to prevent inductance degradation due to magnetostriction. The metallic magnetic material is a soft magnetic material such as Fe, Co, Ni, or an alloy containing these metals (such as FeSi-based alloys such as FeSiCr and FeSiAl, FeCo-based alloys, and NiFe-based alloys such as NiFe), or an amorphous alloy of these metals. The organic material is an organic insulating material such as an epoxy resin, polyimide, liquid crystal polymer, or bismaleimide.

[0086] The conductors 3a to 3c that penetrate the magnetic bodies 4a to 4c and the core-penetrating conductor 7 are made of a metal material with low volume resistivity. As the metal material, it is desirable to use a material mainly containing Cu because of its ease of processing and commonality with the conductors used in the wiring layer (circuit layer).

[0087] The insulating layers 101-103, 201-203 that make up the substrate 10, the first and second cell insulating parts 21, 22, the sealing member 8, and the printed circuit board are made of, for example, a thermosetting resin and an inorganic filler or cloth fibers of an inorganic material. Examples of the thermosetting resin include epoxy resin, acrylic resin, and polyimide. The inorganic filler or cloth fibers of an inorganic material are made of, for example, SiO ２ It consists of the following:

[0088] The wiring layers 110-130, 210-230 constituting the circuit board 1 are, for example, metal layers primarily made of Cu. The via conductors arranged in the insulating layers 101-103, 201-203 are also metal conductors primarily made of Cu. Of the wiring layers, those exposed by the openings in the solder resist layers 105, 205 may have an AuNi coating formed on the surface or may be subjected to anti-rust treatment for the purposes of corrosion prevention, rust prevention, or improving solder wettability.

[0089] [Method for Manufacturing Circuit Board] The method for manufacturing the circuit board 1 includes the following steps: (1) a step for preparing components such as an inductor unit cell and a two-terminal capacitor, (2) an embedding step for arranging components such as an inductor unit cell inside a substrate, and (3) a wiring structure forming step for forming wiring structures on the front and back surfaces of the substrate. The component preparation step (1) includes a manufacturing step for an inductor unit cell. Each step will be described in order below.

[0090] 7A to 14A are schematic top views illustrating steps in a method for manufacturing an inductor unit cell, and FIGS. 7B to 14B are schematic cross-sectional views along line AA shown in FIGS. 7A to 14A.

[0091] 7A and 7B , a magnetic block 40 that serves as the magnetic body (magnetic base body) of an inductor unit cell is formed by a method such as pressure molding. Next, a plurality of (six in this example) magnetic through-holes 41 are formed in the magnetic block 40 by drilling or the like. The magnetic through-holes 41 are arranged at a distance from one another in a plan view.

[0092] Here, for example, a flat magnetic material block 40 having a thickness of 1.8 mm is molded by hot pressing. Then, a cylindrical magnetic material through-hole 41 having a diameter of 1.1 mm is formed in the magnetic material block 40 using a drill (drill diameter: 1.1 mm). After molding the magnetic material block 40, the magnetic material block 40 may be processed to a desired thickness by grinding or the like.

[0093] Next, as shown in FIGS. 8A and 8B, the conductors 3 are placed in the magnetic through-holes 41 of the magnetic block 40.

[0094] 9A and 9B , a resin material is used to form a resin member that seals the gap between the inner wall of the magnetic through hole 41 and the peripheral surface of the conductor 3 from the upper and lower surfaces of the magnetic block 40. Here, a thermosetting resin primarily made of epoxy is used as the resin material. The resin member includes an insulating portion 23 located between the inner wall of the magnetic through hole 41 and the conductor 3, a sealing insulating layer 24 that covers the lower surfaces of the magnetic block 40 and the conductor 3, and a sealing insulating layer 25 that covers the upper surfaces of the magnetic block 40 and the conductor 3. After sealing with the resin material, the thicknesses of the sealing insulating layers 24 and 25 may be adjusted by means of grinding or the like.

[0095] 10A and 10B , an insulating layer 26 is formed on the lower surface of the magnetic block 40, followed by a lower conductor layer 311. Similarly, an insulating layer 27 is formed on the upper surface of the magnetic block 40, followed by a lower conductor layer 321. For example, insulating layers 26 and 27 are formed as layers made of a thermosetting resin and an inorganic filler or inorganic cross fibers. In this specification, the insulating portion 21 including the insulating layer 26 and the sealing insulating layer 24 is referred to as the "first cell insulating portion." Furthermore, the insulating portion 22 including the insulating layer 27 and the sealing insulating layer 25 is referred to as the "second cell insulating portion."

[0096] 11A and 11B , pattern etching is performed on portions of each of the lower conductor layers 311 and 321 to form multiple openings. The openings are arranged to overlap the end faces e1 and e2 of the multiple conductors 3 in a plan view. Next, the portions of the first and second cell insulating portions 21 and 22 exposed by the openings are removed using a laser drill or the like. As a result, via holes 21h are formed in the first cell insulating portion 21 and the lower conductor layer 311 on the underside of the magnetic block 40, exposing the first end faces e1 of the conductors 3. Furthermore, via holes 22h are formed in the second cell insulating portion 22 and the lower conductor layer 321 on the upper side of the magnetic block 40, exposing the second end faces e2 of the conductors 3.

[0097] Next, electroless plating and electrolytic plating are performed on the surface layers of the lower conductor layers 311 and 321 and on the surface layers of the portions of the conductor 3 exposed by the via holes 21h and 22h. As a result, as shown in FIGS. 12A and 12B , via conductors 33 are formed in the via holes 21h, and a conductor layer 312 is formed on the first cell insulating portion 21. The conductor layer 312 is electrically connected to the first end surface e1 of the conductor 3 by the via conductor 33. The conductor layer 312 includes the lower conductor layer 311 and a plating layer. Similarly, via conductors 34 are formed in the via holes 22h, and a conductor layer 322 is formed on the second cell insulating portion 22. The conductor layer 322 is electrically connected to the second end surface e2 of the conductor 3 by the via conductor 34.

[0098] Next, each of the conductor layers 312 and 322 is patterned into a desired shape. As a result, a plurality of first electrodes 31 arranged at a distance from each other are formed from the conductor layer 312, as shown in Figures 13A and 13B. Similarly, a plurality of second electrodes 32 arranged at a distance from each other are formed from the conductor layer 322. Each first electrode 31 and one corresponding second electrode 32 are positioned opposite each other in the Z direction, with the corresponding conductor 3 sandwiched between them.

[0099] 14A and 14B, the magnetic material block 40 is then cut into individual pieces using a dicer or the like to obtain a plurality (six in this case) of inductor unit cells 20. Each inductor unit cell 20 has one conductor 3, a magnetic material 4 positioned around the conductor 3, and a first electrode 31 and a second electrode 32 electrically connected to the conductor 3. Three of the six inductor unit cells 20 manufactured in this manner are used as inductor unit cells 20a to 20c to be built into a circuit board.

[0100] 15A to 17A are schematic top views illustrating the steps of a method for manufacturing a circuit board (embedding step), and FIGS. 15B to 17B are schematic cross-sectional views along lines XVB-XVB to XVIIB-XVIIB shown in FIGS. 15A to 17A, respectively.

[0101] 15A and 15B, a plate-shaped substrate 10 having a first surface 11 and a second surface 12 is prepared. The substrate 10 is made of, for example, a thermosetting resin and an inorganic filler or inorganic cross fibers. Through holes (core through holes) 13a to 13c, 14, and 15, and a plurality of through holes 16 are formed in predetermined positions in the substrate 10 by drilling or router processing.

[0102] 16A and 16B, inductor unit cells 20a to 20c are placed in through holes 13a to 13c, respectively. Similarly, a two-terminal capacitor that will become input capacitor 5 is placed in through hole 14, and a two-terminal capacitor that will become output capacitor 6 is placed in through hole 15. A through-core conductor 7 is placed in each of the multiple through holes 16.

[0103] Next, as shown in FIGS. 17A and 17B , the embedded components, such as the inductor unit cells 20a-20c, are encapsulated within the substrate 10 using an encapsulating member 8. The encapsulating member 8 is an insulating layer formed of a thermosetting resin and an inorganic filler or inorganic cross fibers. The encapsulating member 8 includes a lower insulating layer 81 located on the first surface 11 of the substrate 10 and an upper insulating layer 82 located on the second surface 12. The encapsulating member 8 further includes insulating portions 83 disposed to fill gaps between the inner walls of the through-holes 13a-16 and the circumferential surfaces of the embedded components. After the encapsulating member 8 is formed, the thickness of the encapsulating member 8 (the lower insulating layer 81 and the upper insulating layer 82) may be adjusted by grinding or the like. In this manner, a component-embedded substrate 300 is formed in which the inductor unit cells 20a-20c, the capacitors 5 and 6, and the through-core conductor 7 are embedded.

[0104] (Wiring structure forming process) Figures 18A to 24A are schematic top views showing the manufacturing method of a circuit board (wiring structure forming process). Figures 18B to 24B are bottom views showing the processes corresponding to Figures 18A to 24A, respectively. Figures 18C to 24C are schematic cross-sectional views showing the processes along lines XVIIIC-XVIIIC to XXIVC-XXIVC shown in Figures 18A to 24A, respectively.

[0105] The steps of forming each wiring layer constituting the wiring structure include, for example, the following steps: (i) forming an insulating layer and a lower conductor layer, (ii) forming an opening in the lower conductor layer, (iii) forming a via hole by removing a portion of the insulating layer located within the opening, (iv) forming an upper conductor layer (e.g., a plating layer) in the via hole and on the lower conductor layer to form a via conductor and obtain a conductor layer electrically connected to an electrode on the opposite side of the via conductor, and (v) patterning the conductor layer to obtain a wiring layer including a plurality of electrodes, wiring, terminal portions, etc.

[0106] 18A to 18C , an insulating layer 101 is formed on the first surface 11 of the component-embedded substrate 300, and then a lower conductor layer 1101 made of Cu foil is formed thereon. Similarly, an insulating layer 201 is formed on the second surface 12 of the substrate 10, and then a lower conductor layer 2101 made of Cu foil is formed thereon. The insulating layers 101 and 201 are layers made of, for example, a thermosetting resin and an inorganic filler or cross fibers of an inorganic material.

[0107] In this embodiment, an insulating portion (hereinafter referred to as a "first insulating portion") 91 located between the lower conductor layer 1101 and each electrode of the built-in component (e.g., first electrodes 31a to 31c) includes an insulating layer 101 and a lower insulating layer 81. An insulating portion (hereinafter referred to as a "second insulating portion") 92 located between the lower conductor layer 2101 and each electrode of the built-in component (e.g., second electrodes 32a to 32c) includes an insulating layer 201 and an upper insulating layer 82.

[0108] <Steps (ii) and (iii)> Next, as shown in FIGS. 19A to 19C , pattern etching is performed on each of the lower conductor layers 1101 and 2101 to form multiple openings (step (ii)). After this, the portions of the first and second insulating portions 91 and 92 exposed by the openings are removed using a laser drill or the like (step (iii)). As a result, multiple via holes 91h are formed in the first insulating portion 91 and the lower conductor layer 1101 on the first surface 11 side of the substrate 10. Each via hole 91h exposes a portion of the electrode on the first surface 11 side of the corresponding embedded component. Furthermore, multiple via holes 92h are formed in the second insulating portion 92 and the lower conductor layer 2101 on the second surface 12 side of the substrate 10. Each via hole 92h exposes a portion of the electrode on the second surface 12 side of the corresponding embedded component.

[0109] <Step (iv)> Next, electroless plating and electrolytic plating are applied to the surface layers of the lower conductor layers 1101, 2101 and the surface layers of the portions of the electrodes of the built-in components exposed by the via holes 91h, 92h. As a result, as shown in FIGS. 20A to 20C , multiple via conductors v1 are formed in the via holes 91h, and a conductor layer 1102 is formed on the first insulating portion 91. The conductor layer 1102 is electrically connected to each built-in component by the via conductors v1. Similarly, multiple via conductors v2 are formed in the via holes 92h, and a conductor layer 2102 is formed on the second insulating portion 92. The conductor layer 2102 is electrically connected to each built-in component by the via conductors v2.

[0110] <Step (v)> Next, each of the conductor layers 1102 and 2102 is patterned into a desired shape (step (v)). As shown in Figures 21A to 21C, patterning the conductor layer 1102 results in a wiring layer 110 including a plurality of electrodes such as a first connection electrode 111, a first inductor connection electrode 112, and a first input capacitor connection electrode 113. Furthermore, patterning the conductor layer 2102 results in a wiring layer 210 including a plurality of electrodes such as a second inductor connection electrode 211, a second connection electrode 212, a second input capacitor connection electrode 213, and an output capacitor connection electrode 214.

[0111] 22A and 22B , by steps similar to the above steps (i) to (v), wiring layer 120 is formed on wiring layer 110 with insulating layer 102 interposed therebetween, and wiring layer 220 is formed on wiring layer 210 with insulating layer 202 interposed therebetween. Each of wiring layers 120 and 220 has a plurality of electrodes having a desired pattern.

[0112] Next, as shown in Figures 23A and 23B, by steps similar to the above steps (i) to (v), wiring layer 130 is formed on wiring layer 120 via insulating layer 103, and wiring layer 230 is formed on wiring layer 220 via insulating layer 203.

[0113] In this embodiment, as shown in Fig. 23B, the wiring layer 130 has terminal portions such as a control terminal CTL, an input terminal Vin, an output terminal Vout, and a ground terminal GND. As shown in Fig. 23A, the wiring layer 230 has terminal lands Ld_SW_Vin, Ld_SW_Vout, Ld_SW_GND, and Ld_SW-CTL for each terminal (SW_Vin, SW_Vout, SW_GND, and SW-CTL) of the switch element SW (see Fig. 6).

[0114] 24A and 24B , a solder resist layer 105 is formed on the wiring layer 130, and a solder resist layer 205 is formed on the wiring layer 230. The solder resist layers 105 and 205 each have openings that expose portions of the wiring layers 130 and 230 that will become lands. The surfaces (conductor surfaces) of the portions of the wiring layers 120 and 230 that are exposed by the openings in the solder resist layers 105 and 205 may be subjected to NiAu corrosion prevention, rust prevention, or other surface treatments. In this manner, the circuit board 1 is manufactured.

[0115] [Effects] First, for comparison, a magnetic core assembly of a reference example incorporating an inductor (vertical inductor) through which current flows in the thickness direction will be described. Figure 46 is a schematic cross-sectional view of a magnetic core assembly 700, a reference example created by the present inventor with reference to the contents of Patent Document 1. In the magnetic core assembly 700 of the reference example, two inductors 710 and 720 are formed by arranging a U-shaped conductor 702 so that it penetrates the magnetic core 701 in the thickness direction. The inductors 710 and 720 are connected in parallel with each other. With this structure, the conductor 702 may need to be taller to achieve the desired inductance value, resulting in a thick magnetic core assembly 700.

[0116] The reference example shown in FIG. 46 may also have the following problem. The magnetic core assembly 700 is electrically and mechanically connected to the upper and lower printed circuit boards 703 and 705 by soldering or the like. Specifically, the upper end of the conductor 702 is connected to a bonding pad 704 on the printed circuit board 703 using solder. The lower end (the bent portion) of the conductor 702 is connected to a bonding pad 706 on the printed circuit board 705 using solder. In this structure, the presence of the bent portion makes it difficult to achieve miniaturization. Furthermore, in this structure, the connections between the assemblies may be partial (the connection portions between the assemblies may be discretely arranged, resulting in air gaps between the assemblies). As a result, mechanical stress may be concentrated at the connection points between the assemblies, potentially reducing connection reliability.

[0117] In contrast, in this embodiment, the inductor 2 is built into the circuit board 1, so that a smaller and thinner voltage regulation module can be constructed than in a structure in which printed circuit boards are placed on both sides of the inductor as shown in Figure 46.

[0118] Furthermore, with the circuit board 1 of this embodiment, it is possible to arrange three or more divided vertical inductors, through which current flows in the thickness direction (perpendicular to the circuit surface), within the substrate 10. The bent portions as in the reference example are not necessary. This allows the component-embedded substrate 300 to be made thinner while still maintaining the desired inductance value. Therefore, by using this circuit board 1, the voltage regulation module can be made even thinner.

[0119] Furthermore, according to the circuit board 1 of this embodiment, the inductor 2 (inductor unit cells 20a to 20c) is fixed to the wiring layers 110 and 210 at their surfaces via insulating portions 91 and 92, thereby dramatically improving the mechanical connection stability of the inductor 2 compared to the structure of the reference example shown in FIG.

[0120] In the circuit board 1 of this embodiment, the number of inductor unit cells (the number of conductors 3a to 3c) constituting the inductor 2 is three. This makes it easy to connect one of the input and output terminals of the inductor 2 to an electrode on the first surface 11 of the substrate 10 and the other to an electrode on the second surface 12. Therefore, when the circuit board 1 is applied to a voltage regulation module (see FIG. 45 ), the path from the switch output terminal SW_Vout to the input terminal of the inductor 2 and the path from the output terminal of the inductor 2 to the output terminal Vout of the module can be shortened. As a result, the electrical resistance of the voltage regulation module can be reduced, thereby improving the efficiency of the voltage regulation module.

[0121] Although the illustrated circuit board 1 includes three inductor unit cells, the number of inductor unit cells is not particularly limited and may be one or more. It is preferable that the number of inductor unit cells is an odd number. An odd number makes it easy to connect the input and output terminals of the inductor 2 to wiring layers on opposite sides of the substrate 10. Therefore, when the circuit board 1 is applied to a voltage regulation module, it becomes possible to shorten the current path excluding the inductor 2.

[0122] In the circuit board 1 of this embodiment, the first electrodes 31a-31c and second electrodes 32a-32c (collectively referred to as "inductor electrodes") of the inductor unit cells 20a-20c are arranged so as to overlap the entire conductor and at least a portion of the magnetic material in a plan view. This allows multiple via conductors to be arranged on each inductor electrode for connection to electrodes in the wiring layers 110 and 210, thereby increasing the connection area. This reduces connection resistance and improves connection reliability.

[0123] According to this embodiment, by making the inductor electrodes larger than the conductors in a plan view, it is possible to arrange multiple via conductors connecting the first electrodes 31a, 31b and the first connection electrode 111 in an area larger than the end faces of the conductors 3a, 3b in a plan view. At least one of the via conductors may be located outside the corresponding conductor 3a, 3b in a plan view. Similarly, multiple via conductors connecting the second electrodes 32b, 32c and the second connection electrode 212 can be arranged in an area larger than the end faces of the conductors 3a, 3b in a plan view. This reduces the connection resistance between the inductor unit cells, thereby reducing the DC resistance of the inductor 2 composed of the inductor unit cells 20a to 20c.

[0124] The circuit board 1 of this embodiment includes at least one two-terminal capacitor 5, 6 located inside the substrate 10. The at least one two-terminal capacitor 5, 6 and the inductor 2 are arranged in parallel in a direction intersecting the Z direction. By using such a circuit board 1, it is possible to further reduce the thickness of the voltage regulation module compared to a structure in which the capacitor and inductor are arranged in the thickness direction (for example, Patent Document 1).

[0125] The two-terminal capacitor (e.g., input capacitor 5) in this embodiment includes a dielectric 53, a lower electrode 51 located on the first surface 11 side of the dielectric 53, and an upper electrode 52 located on the second surface 12 side of the dielectric 53. The lower electrode 51 is electrically connected to the wiring in the first wiring layer 110 through a via conductor provided in the first insulating portion 91. The upper electrode 52 is electrically connected to the wiring in the second wiring layer 210 through a via conductor provided in the second insulating portion 92. This configuration can reduce the connection resistance between each electrode of the two-terminal capacitor and the wiring layer, thereby improving connection reliability.

[0126] The circuit board of the present invention is not limited to the embodiments shown in Figures 1 to 24C, and can be embodied in various other forms. For example, one or both of the input capacitor and the output capacitor do not have to be disposed inside the substrate 10. Also, two or more inductors 2 may be built into the substrate 10. Furthermore, the layout of the built-in components in the substrate 10, the circuit configuration of the circuit board 1, the number of wiring layers of the circuit board 1, the electrode patterns within the wiring layers, and the like are not limited to the examples shown in the drawings and can be selected as appropriate.

[0127] In the above embodiment, each of the inductor unit cells 20a to 20c has a single conductor that penetrates the magnetic material. However, two or more conductors that penetrate the magnetic material may be arranged within one inductor unit cell. These conductors may be arranged at a distance from each other and connected in parallel by inductor electrodes. In other words, one inductor unit cell may be composed of two or more inductors connected in parallel.

[0128] As described above, each inductor unit cell functions independently as an inductor. Therefore, by connecting three conductors 3a to 3c in parallel, it is possible to configure three inductors from the conductors 3a to 3c and the magnetic materials 4a to 4c. In this case, the first electrodes 31a to 31c may all be electrically connected to the first connection electrode 111, and the second electrodes 32a to 32c may all be electrically connected to the second connection electrode 212.

[0129] Second Embodiment The circuit board of the second embodiment differs from the circuit board of the first embodiment in that three inductor unit cells are integrally formed. The following description will mainly focus on the differences from the circuit board of the first embodiment, and will omit redundant description where appropriate.

[0130] 25A and 25B are schematic top and bottom views, respectively, showing a component-embedded substrate and some wiring layers in a circuit board according to this embodiment. Fig. 25C is a schematic cross-sectional view taken along line XXVC-XXVC in Fig. 25A and Fig. 25B. Fig. 25C also shows wiring layers 110 and 210. For ease of understanding, electrodes in wiring layers 210 and 110 are indicated by dashed two-dot lines in Fig. 25A and Fig. 25B.

[0131] 3A to 3C in that the component-embedded substrate 300a has an inductor 2 disposed as a single component in a single through-hole 13 in the substrate 10. The inductor 2 of this embodiment also differs from the inductor 2 shown in FIGS. 3A to 3C in that the magnetic materials 4a to 4c are integrally formed (connected), and that the two first electrodes 31a, 31b are integrally formed, and the two second electrodes 32b, 32c are integrally formed.

[0132] The inductor 2 includes a magnetic layer 4L, conductors 3a to 3c, first electrodes 31ab and 31c, and second electrodes 32a and 32bc.

[0133] The magnetic layer 4L has a rectangular parallelepiped shape that is long in the X direction. Three magnetic through-holes 41 are provided in the magnetic layer 4L at a distance from each other in a plan view. The conductors 3a to 3c are disposed in the magnetic through-holes 41, respectively. Portions 4a to 4c of the magnetic layer 4L that are positioned so as to surround the peripheral surfaces of the conductors 3a to 3c form the magnetic elements of the inductor unit cells 20a to 20c, respectively. The magnetic elements 4a to 4c are continuous (connected), and no partition wall of the substrate 10 is disposed between adjacent magnetic elements.

[0134] The first electrode 31ab is an electrode formed by integrating the first electrodes 31a and 31b shown in Figures 3A to 3C. The first electrode 31ab is disposed on the first surface 11 side of the magnetic layer 4L at a distance from the first electrode 31c. The first electrode 31ab is electrically connected to first ends of the conductors 3a and 3b. The first electrode 31ab is electrically connected to the first connection electrode 111 through a via conductor in the first insulating portion 91.

[0135] The second electrode 32bc is an electrode formed integrally with the second electrodes 32b and 32c shown in Figures 3A to 3C. The second electrode 32bc is disposed on the second surface 12 side of the magnetic layer 4L at a distance from the second electrode 32a. The second electrode 32bc is electrically connected to the second ends of the conductors 3b and 3c. The second electrode 32bc is electrically connected to the second connection electrode 212 through a via conductor in the second insulating portion 92.

[0136] In the illustrated example, the first electrode 31ab overlaps the entire conductors 3a and 3b in a planar view. The first electrode 31ab may be slightly smaller than the first connection electrode 111 and positioned inside the outline of the first connection electrode 111 in a planar view. Similarly, the second electrode 32bc overlaps the entire conductors 3b and 3c in a planar view. The second electrode 32bc may be positioned inside the outline of the second connection electrode 212 in a planar view.

[0137] [Method for Manufacturing Circuit Board] The method for manufacturing the circuit board 1 of this embodiment is the same as the method for manufacturing the circuit board 1 of the first embodiment described with reference to Figures 7A to 24C. Below, only the differences from the first embodiment will be described, and overlapping descriptions will be omitted.

[0138] 26A and 27A are schematic top views illustrating steps in a method for manufacturing an inductor unit cell. 28A and 29A are schematic top views illustrating steps in a method for manufacturing a circuit board (embedding step). 26B to 29B are schematic cross-sectional views along lines XXVIB-XXVIB and XXIXB-XXIXB shown in FIGS. 26A to 29A, respectively.

[0139] First, the conductor layers 312 and 322 are formed and patterned using a method similar to that described with reference to FIGS. 7A to 12B. In this embodiment, as shown in FIGS. 26A and 26B, one first electrode 31ab connected to the conductors 3a and 3b and one first electrode 31c connected to the conductor 3c are formed from the conductor layer 312. Furthermore, a second electrode 32a connected to the conductor 3a and a second electrode 32bc connected to the conductors 3b and 3c are formed from the conductor layer 322. Then, as shown in FIGS. 27A and 27B, the magnetic block 40 is cut. Here, the magnetic layer 4L is cut out so as to include the conductors 3a to 3c and the surrounding magnetic bodies 4a to 4c. In this manner, the inductor 2 including the inductor unit cells 20a to 20c is obtained.

[0140] Next, as shown in Figures 28A and 28B, a substrate 10 is prepared having one through-hole 13 in the inductor placement area. Thereafter, as shown in Figures 29A and 29B, the inductor 2 obtained by the above method is placed in the through-hole 13. Predetermined components are also placed in the through-holes 14 to 16, and the resulting structure is sealed with a sealing member 8. Subsequent processes are the same as those in the first embodiment.

[0141] [Effect] In the circuit board 1 of this embodiment, the magnetic bodies 4a to 4c of the multiple inductor unit cells 20a to 20c are integrally formed, which reduces the area of ​​the inductor formation region of the substrate 10. Therefore, the circuit board 1 can be made smaller.

[0142] Furthermore, because the first electrodes of the inductor unit cells 20a and 20b are integrally formed, and the second electrodes of the inductor unit cells 20b and 20c are integrally formed, the connection resistance between the inductor unit cells can be reduced, thereby reducing the DC resistance of the inductor 2. As a result, the resistance loss of the circuit can be further reduced.

[0143] 25A to 25C, three inductor unit cells 20a to 20c are integrally formed, but two of these inductor unit cells may be integrally formed, or three or more inductor unit cells may be integrally formed.

[0144] In this embodiment, each of the inductor unit cells 20a to 20c may have two or more conductors connected in parallel. Alternatively, three inductors may be configured from the conductors 3a to 3c and the magnetic bodies 4a to 4c by connecting the conductors 3a to 3c in parallel.

[0145] Third Embodiment (Foundational Findings) There is a demand for reducing the area of ​​a circuit board incorporating components such as a vertical inductor. The "area of ​​a circuit board" refers to the area when viewed along the thickness direction of the board. For example, when two or more vertical inductors are incorporated, the area of ​​the circuit board tends to increase. In particular, when one vertical inductor is divided into multiple inductor unit cells and incorporated, as in the first embodiment, the area of ​​the circuit board tends to increase as the number of inductor unit cells (i.e., the number of conductors connected in series to constitute one inductor) increases. Furthermore, the area of ​​the circuit board may increase not only when conductors constituting an inductor are incorporated, but also when conductors constituting other components, such as transformers that utilize magnetic coupling between conductors, are incorporated.

[0146] Therefore, the present inventors have investigated a configuration that can suppress an increase in the area of ​​a circuit board incorporating multiple conductors and make it smaller. As a result, they have newly discovered that it is possible to reduce the size of a circuit board by arranging multiple conductors at a distance from each other in a single through hole provided in a substrate. The following embodiments are based on this new discovery.

[0147] [Overall Configuration of Circuit Board] As with the first embodiment, the circuit board of this embodiment includes a first wiring structure, a second wiring structure, and a component-embedded substrate located between these wiring structures. The component-embedded substrate includes at least one conductor-containing portion between the first wiring structure and the second wiring structure. The "conductor-containing portion" includes a substrate and a plurality of conductors disposed in through holes of the substrate. Each conductor disposed in the through holes may be a conductor constituting a component such as an inductor. The substrate in which the through holes are provided may be, for example, a substrate (e.g., a magnetic substrate or magnetic layer) disposed inside a core substrate.

[0148] [Configuration of Conductor-Containing Portion] An example of a conductor-containing portion in the circuit board of this embodiment will be described below with reference to the drawings, taking a conductor-containing portion constituting an inductor component as an example.

[0149] Fig. 30 is a schematic perspective view of a conductor-containing portion in a circuit board according to a third embodiment. Fig. 31A is a schematic top view of the conductor-containing portion in Fig. 30. Fig. 31B is a schematic cross-sectional view taken along line XXXIB-XXXIB in Fig. 31A.

[0150] The conductor-containing portion 800 includes a substrate 810, conductors 831 and 832, and a separation insulating layer 840. In this example, the substrate 810 is a magnetic material.

[0151] The substrate 810 has a first surface 811 and a second surface 812 located on the opposite side of the first surface 811 in the thickness direction (Z direction). Although not shown, a first wiring layer is disposed on the first surface 811, and a second wiring layer is disposed on the second surface 812. The substrate 810 has a through-hole 820 extending in the thickness direction. In the example shown, the substrate 810 is, for example, a quadrangular prism (here, a rectangular parallelepiped). The through-hole 820 is, for example, a cylindrical shape.

[0152] The conductors 831 and 832 are arranged in the through hole 820 at a distance from each other in a plan view seen along the Z direction (hereinafter sometimes abbreviated as "plan view"). Each of the conductors 831 and 832 extends in the Z direction. Ends (first ends) of the conductors 831 and 832 on the first surface 811 side are electrically connected to corresponding electrodes in the first wiring layer. Ends (second ends) of the conductors 831 and 832 on the second surface 812 side are electrically connected to corresponding electrodes in the second wiring layer.

[0153] The isolation and insulation layer 840 is located between the conductors 831 and 832 in plan view. The isolation and insulation layer 840 separates the conductors 831 and 832 from each other within the through-hole 820.

[0154] In this specification, a structure M composed of a plurality of conductors arranged in one through hole and an isolation insulating layer for isolating the conductors from each other will be referred to as a “first structure.” The specific structure of the first structure M will be described later.

[0155] An insulating portion 860 is disposed between the inner wall of the through hole 820 and the first structure M. The insulating portion 860 is, for example, a resin member. The insulating portion 860 may be disposed so as to fill the gap between the inner wall of the through hole 820 and the side surface of the first structure M. The insulating portion 860 may contain a magnetic material. This can improve the inductance of an inductor component using the conductors 831, 832 of the conductor-containing portion 800.

[0156] (First Structure M) Each of the conductors 831, 832 of the first structure M is a columnar shape extending in the Z direction. The conductors 831, 832 may be, for example, a polygonal columnar shape having a polygonal cross section with an interior angle of 90° or more and less than 180°. In this specification, the "cross section of the conductor" refers to a cross section of the conductor that is perpendicular to the Z direction (thickness direction of the substrate). In this example, the conductors 831, 832 are configured to have the same size and shape, but the sizes and shapes (cross-sectional shapes) of the conductors 831, 832 may be different.

[0157] In the example shown in Figures 30 to 31B, each of the conductors 831 and 832 is a quadrangular prism with a rectangular cross section. The conductors 831 and 832 are aligned in the Y direction via an isolation / insulation layer 840. In this example, the distance between the conductors 831 and 832 is small, and the conductors 831 and 832 are positioned close to each other. The distance between the conductors 831 and 832 (here, the length of the isolation / insulation layer 840 in the Y direction) is preferably set to the minimum distance that ensures sufficient electrical withstand voltage for the potential difference generated between the conductors 831 and 832. This can increase the coupling coefficient between the conductors and reduce the size of the component or circuit board. The distance between the conductors 831 and 832 is, for example, 60 μm or less.

[0158] The conductor 831 has a first side surface 831a facing the conductor 832 and a second side surface 831b located on the opposite side of the first side surface 831a in the Y direction. Similarly, the conductor 832 has a first side surface 832a facing the conductor 831 and a second side surface 832b located on the opposite side of the first side surface 832a in the Y direction. The first side surface 831a of the conductor 831 and the first side surface 832a of the conductor 832 may be bonded by an isolation insulating layer 840.

[0159] At least a portion of the side portions of the conductors 831 and 832 may be covered with the insulating layer 850. The "side portions of the conductor" refer to the portions of the surface of the conductor that are located between the end face on the first surface side and the end face on the second surface side. In the example shown, the second side surface 831b of the conductor 831 and the second side surface 832b of the conductor 832 are covered with the insulating layer 850. The side surfaces of the conductors 831 and 832 that extend along the Y direction in plan view are not covered with the insulating layer 850 and may be in direct contact with the insulating portion 860, for example.

[0160] 30 to 31B, the first structure M has a quadrangular prism shape. In a plan view, the first structure M has a quadrangular shape that is slightly smaller than the quadrangular shape inscribed in the circular opening of the through-hole 820. With this configuration, when manufacturing the conductor-containing portion 800, it is possible to more easily place the separately formed first structure M in the through-hole 820 of the substrate 810.

[0161] [Effect] The circuit board of this embodiment includes a substrate 810 having a through hole 820 extending in the thickness direction (Z direction), conductors 831 and 832 disposed in the through hole 820 and each extending in the Z direction, and an isolation insulating layer 840 that separates the conductors 831 and 832 at the through hole 820. With this configuration, the area of ​​the circuit board when viewed along the Z direction can be reduced compared to when a through hole is provided for each conductor. Therefore, the circuit board can be made smaller.

[0162] In the circuit board of this embodiment, the conductors 831 and 832 are electrically isolated from each other. For example, first ends of the conductors 831 and 832 may be electrically connected to different electrodes on the first surface 811, and second ends of the conductors 831 and 832 may be electrically connected to different electrodes on the second surface 812. This allows the conductors 831 and 832 to form parts of different components.

[0163] The circuit board of this embodiment may include, for example, a first inductor and a second inductor that can operate independently of each other. In this case, the first inductor may include a conductor 831, and the second inductor may include a conductor 832.

[0164] The first inductor and the second inductor may be formed by a single conductor-containing portion 800, or, as described below, may be formed by a plurality of conductor-containing portions 800. When the first inductor and the second inductor are formed by a plurality of conductor-containing portions 800, the conductors 831 in the plurality of conductor-containing portions 800 may be connected in series to form the first inductor, and the conductors 832 may be connected in series to form the second inductor. With this configuration, the conductors of the vertical inductor can be divided and arranged, thereby making the circuit board thinner. Furthermore, by arranging two or more conductors 831, 832 in one through hole, the area of ​​the circuit board can be reduced. Therefore, the circuit board can be further miniaturized.

[0165] The conductors 831 and 832 may be electrically connected to each other. For example, first ends of the conductors 831 and 832 may be connected to each other by an electrode disposed on the first surface 811, and second ends of the conductors 831 and 832 may be connected to each other by an electrode disposed on the second surface 812.

[0166] (Modification 1) Fig. 32A is a schematic top view of a conductor-containing portion according to Modification 1. Fig. 32B is a schematic cross-sectional view taken along line XXXIIB-XXXIIB in Fig. 32A.

[0167] The conductor-containing portion 801 of variant example 1 shown in Figures 32A and 32B differs from the conductor-containing portion 800 shown in Figures 31A and 31B in that, when viewed in a plan view along the Z direction, the through hole 820 is not circular but has a shape that is elongated in one direction (in this example, the X direction).

[0168] In this modification, the opening shape of the through hole 820 is a track shape (ellipse) that is long in the X direction. The "opening shape of the through hole" refers to the shape of a columnar through hole when viewed from the Z direction, and is the shape of the opening located on the first surface 811 and the second surface 812 of the substrate 810. The "track shape" refers to a shape in which the two short sides of a rectangle are replaced with partial circles or semicircles that protrude outward, such as a racetrack shape, and shapes similar to such a shape. Such a through hole 820 is composed of a quadrangular columnar region Pa and two partial cylindrical regions Pb that are located on both sides of the quadrangular columnar region Pa in the Y direction. The quadrangular columnar region Pa and the partial cylindrical region Pb correspond to the rectangular portion located in the center of the track shape in a plan view and the two partial circular portions located on both sides of the rectangular portion.

[0169] In the example shown in FIGS. 32A and 32B , the first structure M and the through hole 820 both have a shape that is elongated in one direction (X direction) in a plan view. In a plan view, the maximum length Ly of the through hole 820 in the short direction (Y direction) may be smaller than the maximum length w of the first structure M in the longitudinal direction. This allows the first structure M to be arranged in a predetermined orientation in the through hole 820 when manufacturing the conductor-containing portion 801. Specifically, the first structure M is arranged in the through hole 820 such that the longitudinal directions of the through hole 820 and the first structure M coincide or substantially coincide in a plan view. In this example, the first structure M is arranged in the through hole 820 so that the conductors 831 and 832 are aligned in the Y direction (i.e., so that the conductor 831 is located on the −Y side or +Y side of the conductor 832).

[0170] The first structure M1 is disposed, for example, inside the quadrangular prism region Pa of the through hole 820. The first structure M may have a rectangular shape that is slightly smaller than the quadrangular prism region Pa of the through hole 820 in a plan view. The length of the through hole 820 in the Y direction is greatest (length Ly) in the quadrangular prism region Pa and decreases as it moves away from the quadrangular prism region Pa in the X direction. Therefore, if the first structure M has a shape that is slightly smaller than the quadrangular prism region Pa in a plan view, the position of the first structure M in the through hole 820 is less likely to deviate from the quadrangular prism region Pa.

[0171] The conductors 831 and 832 may have the same shape and size. The first structure M may be configured to be point-symmetric with respect to a point located at the center of the isolation insulating layer 840 in a plan view seen along the Z direction. With this configuration, even if the conductors 831 and 832 are rotated 180° from the orientation shown in FIG. 32A and arranged upside down (the conductor 831 is arranged on the +Y side of the conductor 832), it is possible to obtain a conductor-containing portion 801 having substantially the same structure and function as that shown in FIG. 32A .

[0172] According to the circuit configuration of Modification 1, the through hole 820 has an opening shape that is long in one direction. Therefore, when the first structure M is placed in the through hole 820 during the manufacturing process of the conductor-containing portion 801, the orientation of the first structure M with respect to the through hole 820 is determined. This makes it easier to place the conductors 831 and 832 in predetermined positions. As a result, the conductors 831 and 832 can be more reliably connected to predetermined electrodes in the wiring layer. This makes it easier to manufacture the circuit board.

[0173] In addition, in Modification 1, polygonal prism-shaped conductors 831 and 832 are disposed in through-hole 820 having a track-shaped opening. This allows the cross-sectional area of ​​conductors 831 and 832 to be larger than when the opening is circular. This allows the electrical resistance of conductors 831 and 832 to be reduced while suppressing an increase in the area of ​​the circuit board.

[0174] (Modification 2) Fig. 33A is a schematic top view of a conductor-containing portion according to Modification 2. Fig. 33B is a schematic cross-sectional view taken along line XXXIIIB-XXXIIIB in Fig. 33A.

[0175] 33A and 33B differs from the conductor-containing portion 801 shown in Fig. 32A and 32B in the cross-sectional shapes of the conductors 831 and 832. The opening shape of the through-hole 820 of the conductor-containing portion 802 is a track shape.

[0176] In the conductor-containing portion 802, the conductor 831 is configured so that the width of the conductor 831 in the X direction decreases with increasing distance from the conductor 832 in the Y direction. A width w1 along the X direction of a portion of the conductor 831 closest to the conductor 832 is greater than a width w2 along the X direction of a portion of the conductor 831 farthest from the conductor 832. The width w1 is, for example, the length of the first side surface 831a in the X direction, and the width w2 is, for example, the length of the second side surface 831b in the X direction. Similar to the conductor 831, the conductor 832 is also configured so that the width of the conductor 832 in the X direction decreases with increasing distance from the conductor 831 in the Y direction.

[0177] The conductors 831 and 832 may be polygonal prisms (here, quadrangular prisms). In plan view, the conductors 831 and 832 are polygonal with a first side located on the isolation / insulation layer 840 side and a second side adjacent to the first side, and angles c1 and c2 between the first side and the second side may be acute angles. In the example shown in Figures 33A and 33B, the conductors 831 and 832 are each trapezoidal in plan view, with the first side being the bottom base of the trapezoid and the second side being the legs of the trapezoid. The conductors 831 and 832 constitute a first structure M having a substantially hexagonal prism shape.

[0178] The first structure M is disposed in the through hole 820 so that the longitudinal directions of the first structure M and the through hole 820 are approximately aligned in a plan view. The maximum width w1 in the X direction of the first structure M is greater than the length in the X direction of the quadrangular prism region Pa of the through hole 820. Therefore, as shown in FIG. 33A , in a plan view, the first structure M extends from the quadrangular prism region Pa to the insides of the partial cylindrical regions Pb on both sides thereof.

[0179] At least a portion of the side of the conductors 831, 832 may be covered with the insulating layer 850. In the example shown, the entire side of each of the conductors 831, 832 except for the first side surfaces 831a, 832a is covered with the insulating layer 850.

[0180] In the circuit board of Modification 2, at least one of the conductors 831, 832 (here, both) is configured so that its width in the X direction decreases with increasing distance from the other conductor in the Y direction. This makes it difficult for the magnetic field f generated around each of the conductors 831, 832 to be blocked by the corners of the conductors 831, 832, making it easier for them to rotate.

[0181] Furthermore, with the circuit board of Modification 2, the first structure M can extend beyond the rectangular pillar region Pa into the partial cylindrical region Pb. Therefore, in a plan view, the proportion of the area of ​​the first structure M in the through hole 820 can be made larger than, for example, Modification 1. Therefore, the cross-sectional area of ​​the conductors 831 and 832 can be increased while suppressing an increase in the area of ​​the circuit board, thereby reducing electrical resistance. Furthermore, the gap between the inner wall of the through hole 820 and the first structure M can be made smaller, thereby reducing the volume of the insulating portion 860 filled around the conductors 831 and 832. As a result, inductance can be increased.

[0182] (Modification 3) Fig. 34A is a schematic top view of a conductor-containing portion according to Modification 3. Fig. 34B is a schematic cross-sectional view taken along line XXXIVB-XXXIVB in Fig. 34A.

[0183] 34A and 34B , the conductor-containing portion 803 of the third modification example differs from the conductor-containing portions 800 to 802 described above in that the conductors 831 and 832 have different shapes in plan view. In this modification example, the first structure M and the through hole 820 have asymmetric shapes in plan view.

[0184] The conductor 831 has a columnar shape (here, a rectangular prism) similar to the conductor 831 of Modification Example 2 shown in FIGS. 33A and 33B , and is configured so that its width in the X direction decreases with increasing distance from the conductor 832. Like the conductor 831 shown in FIGS. 31A and 31B , the conductor 832 is a rectangular prism with a rectangular cross section. The cross-sectional area of ​​the conductor 832 is larger than that of the conductor 831. In the through-hole 820, a first side surface 831a of the conductor 831 and a first side surface 832a of the conductor 832 face each other in the Y direction with the isolation insulating layer 840 interposed therebetween. The width w3 in the X direction of the conductor 832 (here, the length of the first side surface 832a) is larger than, for example, the maximum width w1 in the X direction of the conductor 831 (here, the length of the first side surface 831a in the X direction).

[0185] Through-hole 820 has a structure in which two cylindrical holes (hereinafter referred to as "first hole" and "second hole") that penetrate base material 810 in the Z direction are arranged so as to partially overlap each other. Through-hole 820 has a first region Pc1 defined by the inner wall of the first hole and a second region Pc2 defined by the inner wall of the second hole.

[0186] In the example shown in FIGS. 34A and 34B , the second hole has a larger radius than the first hole. In a plan view, the area of ​​the second region Pc2 is larger than the area of ​​the first region Pc1. The conductor 832 is located, for example, inside the second region Pc2. In a plan view, the conductor 832 may have a rectangular shape that is slightly smaller than the rectangle inscribed in the partially circular second region Pc2. At least a portion of the conductor 831 is located inside the first region Pc1. The conductor 831 may extend from the first region Pc1 to the second region Pc2. A design method for the through hole 820 and the conductors 831 and 832 of this modification will be described later with reference to FIG. 44A .

[0187] In the circuit board of Modification 3, the through hole 820 has an asymmetric shape in a plan view, and the first structure M also has an asymmetric shape corresponding to the through hole 820. With this configuration, the orientation of the first structure M placed in the through hole 820 is determined in only one way. This makes it easier to place the conductors 831 and 832 in their predetermined positions. As a result, the conductors 831 and 832 can be more reliably connected to predetermined electrodes in the wiring layer. This makes it easier to manufacture the circuit board.

[0188] Furthermore, in the circuit board of Modification 3, the cross-sectional areas of the conductors 831 and 832 are different from each other, which is advantageous when the current ratios of the conductors 831 and 832 are different. For example, by placing the conductor 832 with a larger cross-sectional area in a line through which a larger current flows, the electrical resistance of the line can be kept lower.

[0189] Furthermore, in the third modification, the conductor 831 is configured so that its width in the X direction decreases with increasing distance from the conductor 832. This makes it difficult for the conductor 831 to block the magnetic field generated around the conductors 831 and 832, thereby increasing the inductance.

[0190] Furthermore, in Modification 3, the through-hole 820 has a structure in which two cylindrical holes corresponding to the conductors 831 and 832 are arranged so as to partially overlap each other, and the magnetic field (magnetic flux) generated around each of the conductors 831 and 832 easily passes through the magnetic body (substrate 810), thereby further increasing the inductance.

[0191] (Modification 4) Fig. 35A is a schematic top view of a conductor-containing portion according to Modification 4. Fig. 35B is a schematic cross-sectional view taken along line XXXVB-XXXVB in Fig. 35A.

[0192] The conductor-containing portion 804 of variant 4 shown in Figures 35A and 35B differs from the first structure M of variant 3 shown in Figures 34A and 34B in that it has three conductors 831 to 833 arranged in the through hole 820 of the substrate 810.

[0193] In the conductor-containing portion 804, a conductor 833 is arranged on the opposite side of the conductor 832 from the conductor 831 in the through-hole 820. The conductors 831 to 833 are lined up in this order in the Y direction within the through-hole 820, for example.

[0194] The isolation and insulation layer 840 includes a first isolation and insulation layer 841 located between the conductors 831 and 832 , and a second isolation and insulation layer 842 located between the conductors 832 and 833 .

[0195] In the example shown, the conductor 833 is a polygonal prism (here, a quadrangular prism), and a first side surface 833a of the conductor 833 located on the conductor 832 side faces a second side surface 832b of the conductor 832 in the Y direction via a second isolation insulating layer 842.

[0196] The conductor 832 may have a similar shape to the conductor 833. As shown in the figure, the width of the conductor 833 in the X direction may decrease with increasing distance from the conductor 831. The maximum width of the conductor 833 in the X direction (here, the length of the first side surface 833a in the X direction) may be smaller than the width w3 of the conductor 832 in the X direction and may be the same as the width of the conductor 831 in the X direction, for example.

[0197] The length u2 of the conductor 832 in the Y direction may be greater than the lengths u1 and u3 of the conductors 831 and 833 in the Y direction. With this configuration, a larger current can flow through the conductor 831, which has a larger cross-sectional area. As an example, the length u2 of the conductor 832 in the Y direction may be 0.8 mm, and the lengths u1 and u3 of the conductors 831 and 833 in the Y direction may be 0.2 mm.

[0198] The through hole 820 has a structure in which three cylindrical holes (hereinafter referred to as the "first hole," "second hole," and "third hole") that penetrate the substrate 810 in the Z direction are arranged so as to partially overlap. In this example, the through hole 820 has a structure in which the first hole is arranged so as to partially overlap one end of the second hole in the Y direction, and the third hole is arranged so as to partially overlap the other end of the second hole. The through hole 820 has a first region Pc1 defined by the inner wall of the first hole, a third region Pc3 defined by the inner wall of the third hole, and a second region Pc2 located between the first region Pc1 and the third region Pc3 and defined by the inner wall of the second hole.

[0199] In the example shown in Figures 35A and 35B, the radius of the second hole is larger than the radii of the first hole and the third hole. Therefore, the maximum width in the X direction of the second region Pc2 is larger than the maximum width in the X direction of the first region Pc1 and the third region Pc3. In a plan view, the area of ​​the second region Pc2 may be larger than the first region Pc1 and the third region Pc3. The conductor 832 is located within the second region Pc2. At least a portion of the conductor 831 is located within the first region Pc1, and at least a portion of the conductor 833 is located within the third region Pc3.

[0200] The through hole 820 and the first structure M may both have a shape that is long in one direction (here, the Y direction). The maximum length of the through hole 820 in the short direction (X direction) may be smaller than the maximum length of the first structure M in the longitudinal direction (Y direction). This allows the first structure M to be arranged in the through hole 820 in a predetermined orientation when manufacturing the conductor-containing portion 804. Specifically, the first structure M is arranged in the through hole 820 in an orientation such that the longitudinal directions of the through hole 820 and the first structure M coincide or approximately coincide in a plan view.

[0201] The conductors 831 and 833 may be arranged symmetrically on both sides of the conductor 832, thereby configuring the first structure M having a point-symmetric shape in a plan view. As a result, even if the first structure M is arranged in the through-hole 820 upside down from the example shown in Fig. 35A, a conductor-containing portion 804 having substantially the same structure can be manufactured.

[0202] 35A, the first structure M and the through hole 820 have point-symmetric shapes in plan view, but they may have asymmetric shapes. For example, the shapes, sizes, etc. of the conductors 831 and 833 may be different from each other in plan view.

[0203] According to the circuit board of Modification 4, three conductors 831 to 833 can be arranged in one through-hole 820, which allows for further miniaturization of the circuit board. In addition, the cross-sectional area, connection method, current direction, etc. of the conductors 831 to 833 can be designed according to the respective applications (such as the magnitude of the current). This allows for greater design freedom.

[0204] Furthermore, in the circuit board of Modification 4, the width of the conductors 831 and 833 in the X direction decreases with increasing distance from the central conductor 832. With this configuration, the magnetic field generated around each of the conductors 831 to 833 is less likely to be blocked by the conductors 831 and 833. Furthermore, in Modification 4, the through-hole 820 has a structure in which three cylindrical holes corresponding to the conductors 831 to 833 are arranged so as to partially overlap each other, which makes it easier for the magnetic field (magnetic flux) generated around each of the conductors 831 to 833 to pass through the magnetic material (substrate 810). Therefore, the inductance can be further increased.

[0205] Furthermore, in the circuit board of Modification 4, in a plan view, the conductors 831 and 833 are respectively arranged on one end side and the other end side of the conductor 832 in the Y direction, close to the conductor 832. With this configuration, magnetic coupling is easily formed between the two or three inductors formed by the conductors 831 to 833.

[0206] (Modification 5) Fig. 36A is a schematic top view of a conductor-containing portion according to Modification 5. Fig. 36B is a schematic cross-sectional view taken along line XXXVIB-XXXVIB in Fig. 36A.

[0207] The conductor-containing portion 805 of modified example 5 shown in Figures 36A and 36B differs from the conductor-containing portion 804 of modified example 4 shown in Figures 35A and 35B in that the through hole 820 of the substrate 810 has a track shape that is long in the Y direction.

[0208] In the illustrated example, the conductor 832 is disposed in a quadrangular prism region Pa of the through-hole 820. In a plan view, the conductor 831 has a rectangular shape that is slightly smaller than the quadrangular prism region Pa. The conductors 831 and 833 are each disposed in a partial cylindrical region Pb of the through-hole 820. It is sufficient that at least a portion of the conductors 831 and 833 is disposed in the partial cylindrical region Pb.

[0209] According to the fifth modification, similarly to the fourth modification, the magnetic field generated around each of the conductors 831 to 833 is less likely to be blocked by the conductors 831 and 833 .

[0210] Furthermore, according to the fifth modification, the opening of the through hole 820 can be made smaller than in the fourth modification. This allows the area of ​​the circuit board to be further reduced. Furthermore, since the gap between the first structure M and the inner wall of the through hole 820 can be made smaller, the magnetic substrate 4 and the conductor 831 can be brought closer together. Furthermore, since the conductors 831 to 833 are arranged close to each other within the through hole 820 having a track-shaped opening, stronger magnetic coupling can be formed between the two or three inductors formed by the conductors 831 to 833.

[0211] [Configuration of Circuit Board] In the circuit board of this embodiment, the number of conductors in each conductor-containing portion, the method of connecting the conductors, the direction of current, etc. can be arbitrarily combined. Examples of such combinations are shown in Table 1.

[0212]

[0213] In Table 1, "Number of conductors" refers to the number of conductors arranged in one through hole. "Electrical separation" refers to the number of conductors electrically separated from one another in one through hole. "Conductor potential" refers to the potential of each conductor arranged in one through hole, and the potential differs between electrically separated conductors. "Current direction" refers to the direction of current in each conductor arranged in one through hole, with two arrows indicating the two directions along the Z direction. In Table 1, "parallel" refers to the case where the currents in multiple conductors arranged in one through hole and electrically separated from each other all flow in the same direction (all parallel). On the other hand, "anti-parallel" refers to the case where currents flow in two conductors arranged in one through hole and electrically separated from each other in opposite directions (anti-parallel). In addition, "magnetic field direction" refers to the relationship between the directions of the magnetic fields generated around each conductor. "Same" refers to the case where the magnetic field directions of each conductor are the same, and "opposite" refers to the case where the magnetic field directions of each conductor are opposite (counter-rotating). In Table 1, when three conductors are arranged in one through hole, the central conductor in the arrangement direction (e.g., the Y direction) is referred to as the "second conductor," and the conductors at both ends are referred to as the "first conductor" and the "third conductor," respectively.

[0214] The conductors in this embodiment can also be considered as portions obtained by dividing one cylindrical conductor in the first embodiment (one conductor in the inductor unit cell) in the Z direction. In this case, the "number of conductors" is a number representing how many portions one cylindrical conductor in the first embodiment is physically divided into. Furthermore, the "electrical separation" is a number representing how many portions one cylindrical conductor in the first embodiment is electrically divided into.

[0215] The conductor-containing portions 800 to 804 illustrated in Figures 30 to 33B have two conductors and can therefore be applied to the circuit boards of configuration examples (1) to (3). The conductor-containing portions 805 and 806 illustrated in Figures 34A to 35B have three conductors and can therefore be applied to the circuit boards of configuration examples (4) to (11).

[0216] In the circuit board of this embodiment, one or more components (e.g., inductors) can be configured using the conductor-containing portion. Below, an example of an inductor configuration using the conductor-containing portion and an example of a circuit configuration will be described for the circuit boards of configuration examples (2), (3), and (5) shown in Table 1.

[0217] (Configuration Example (2)) <Inductor Configuration> The circuit board of Configuration Example (2) includes, for example, a plurality of conductor-containing portions, a plurality of first electrodes arranged on the first surface sides of the plurality of conductor-containing portions, and a plurality of second electrodes arranged on the second surface sides. This forms two inductors. In each conductor-containing portion, currents flow in opposite directions (anti-parallel) to each other in the Z direction through the two conductors arranged in one through hole.

[0218] 37A and 37B are top and bottom perspective views each showing a conductor-containing portion and a second electrode of the second configuration example (2), respectively. For clarity, the first and second electrodes are indicated by dashed two-dot lines.

[0219] 37A and 37B, a plurality of (here, three) conductor-containing portions 802a to 802c are arranged in this order in the X direction on the circuit board. In each of the conductor-containing portions 802a to 802c, two conductors 831 and 832 are disposed in a through-hole 820. The conductor 832 is located on the +Y side of the conductor 831.

[0220] In this example, each of the conductor-containing portions 802a to 802c has the same configuration as the conductor-containing portion 802 shown in Figures 33A and 33B. Note that the configuration of these conductor-containing portions is not limited to the example shown in the figures, and may be, for example, any of the conductor-containing portions 800 to 804 shown in Figures 30 to 33B.

[0221] A plurality of (four in this example) first electrodes 901ab, 901c, 902a, and 902bc are provided on the first surface 811 side of the conductor-containing portions 802a to 802c. The first electrodes may be arranged in a first wiring layer 110 (FIG. 2) that is closest to the first surface 811 in the first wiring structure 100 (FIG. 2). A plurality of (four in this example) second electrodes 911a, 911bc, 912ab, and 912c are provided on the second surface 812 side of the conductor-containing portions 802a to 802c. The second electrodes may be arranged in a second wiring layer 210 (FIG. 2) that is closest to the second surface 812 in the second wiring structure 200 (FIG. 2).

[0222] In each of the conductor-containing portions 802a to 802c, the end (first end) of the conductors 831 and 832 on the first surface 811 side is electrically connected to one of the corresponding first electrodes, and the end (second end) on the second surface 812 side is electrically connected to one of the corresponding second electrodes. Each end of the conductors 831 and 832 may be electrically connected to the corresponding first electrode or second electrode via, for example, a via conductor. Another electrode (an electrode corresponding to electrodes 31 and 32 in the above-described embodiment) may be interposed between the end of each conductor and the first electrode or second electrode.

[0223] In this configuration example, the conductors 831 of the conductor-containing portions 802a to 802c are connected in series to form one inductor 2a, and the conductors 832 of the conductor-containing portions 802a to 802c are connected in series to form one inductor 2b.

[0224] The inductor 2a includes conductors 831 of conductor-containing portions 802a to 802c, first electrodes 901ab and 901c, and second electrodes 911a and 911bc. A second end of the conductor 831 of the conductor-containing portion 802a is connected to the second electrode 911a and is electrically connected to a predetermined terminal via the second electrode 911a. First ends of the conductors 831 of the conductor-containing portions 802a and 802b are electrically connected to each other via the first electrode 901ab. Second ends of the conductors 831 of the conductor-containing portions 802b and 802c are electrically connected to each other via the second electrode 911bc. A first end of the conductor 831 of the conductor-containing portion 802c is connected to the first electrode 901c and is electrically connected to a predetermined terminal via the first electrode 901c.

[0225] Inductor 2b includes conductors 832 in conductor-containing portions 802a to 802c, first electrodes 902a and 902bc, and second electrodes 912ab and 912c. A first end of conductor 832 in conductor-containing portion 802a is connected to first electrode 902a and is electrically connected to a predetermined terminal via first electrode 902a. Second ends of conductors 832 in conductor-containing portions 802a and 802b are electrically connected to each other via second electrode 912ab. First ends of conductors 832 in conductor-containing portions 802b and 802c are electrically connected to each other via first electrode 902bc. A second end of conductor 832 in conductor-containing portion 802c is connected to second electrode 912c and is electrically connected to a predetermined terminal via second electrode 912c.

[0226] In this specification, an electrode that electrically connects two conductors arranged in different through holes 820 may be referred to as a "connection electrode." In the example shown in the figure, first electrodes 901ab, 902bc and second electrodes 911bc, 912ab function as connection electrodes.

[0227] In the circuit board of configuration example (2), the conductors 831 and 832 are electrically isolated. This configuration allows the conductors 831 and 832 to form different components (here, inductors 2a and 2b). Therefore, more components can be built in while minimizing an increase in the area of ​​the circuit board. Furthermore, similar to the first embodiment, the inductors (vertical inductors) 2a and 2b can be formed by connecting the conductors of multiple (here, three) conductor-containing portions 802a to 802c in series. In other words, the conductor-containing portions 802a to 802c can function as inductor unit cells. This configuration allows the circuit board to be made thinner.

[0228] Furthermore, in the circuit board of configuration example (2), the conductors 831 and 832 are connected to the corresponding electrodes so that the currents flow in the conductors 831 and 832 in antiparallel directions, and therefore the magnetic fields generated by the conductors 831 and 832 are opposite in direction (counter-rotating).

[0229] FIG. 37C is a schematic enlarged top view illustrating the magnetic fields generated in conductors 831 and 832. This figure illustrates magnetic fields f1 and f2 when a current flows in the +Z direction (from the first end to the second end) through conductor 831 and a current flows in the -Z direction (from the second end to the first end) through conductor 832. As shown in FIG. 37C, in each conductor-containing portion, magnetic field f1 generated around conductor 831 and magnetic field f2 generated around conductor 832 are in opposite directions (counterrotating) and cancel each other out. As a result, magnetic saturation is less likely to occur. Therefore, it is possible to prevent the inductor characteristics of each inductor formed by conductors 831 and 832 from being reduced by magnetic saturation.

[0230] When the conductors 831 and 832 are arranged close to each other within the through-hole 820, the two magnetic fields f1 and f2 are closer to each other, so they can cancel each other out more effectively. The amounts of current flowing through the conductors 831 and 832 may be approximately equal. This makes it possible to more effectively suppress magnetic saturation.

[0231] <Circuit Configuration> Fig. 38A is a diagram showing an example of the circuit configuration of a voltage regulation module (step-down DC-DC converter) using the circuit board of configuration example (2). Fig. 38B is a diagram showing a simplified version of the circuit configuration shown in Fig. 38A. The voltage regulation modules shown in Figs. 38A and 38B are DC-DC converters having multiple phases (multiphase).

[0232] 38A and 38B includes the circuit board of configuration example (2) and two switch elements SW1 and SW2. This module has a phase 1 in which switch element SW1 is ON and switch element SW2 is OFF, and a phase 2 in which switch element SW2 is ON and switch element SW1 is OFF.

[0233] The inductors 2a and 2b, the input capacitor 5, and the output capacitor 6 that constitute the circuit are built into a circuit board (a substrate with built-in components). The capacitors 5 and 6 may have the same structure as in the first embodiment. Terminal portions such as the control terminal CTL, the input terminal Vin, the output terminal Vout, and the ground terminal GND are formed, for example, in a first wiring structure (see FIG. 23A). Furthermore, terminal lands for the terminals of the switch elements SW1 and SW2 (SW1_CTL, SW2_CTL, SW1_Vout, SW2_Vout, SW_GND, etc.) are formed, for example, in a second wiring structure (see FIG. 23B).

[0234] Inductor 2a is connected between the SW1_Vout terminal of switch element SW1 and the output terminal Vout. Inductor 2b is connected between the SW2_Vout terminal of switch element SW2 and the output terminal Vout. Inductors 2a and 2b have, for example, the structures illustrated in FIGS. 37A and 37B. In each of conductor-containing portions 802a to 802c, the direction of current flowing through conductor 831 constituting inductor 2a is opposite to the direction of current flowing through conductor 832 constituting inductor 2b (anti-parallel).

[0235] The two conductors in each conductor-containing portion are preferably arranged close enough to allow magnetic coupling to occur. The reason for this will be explained with reference to Figures 38C and 38D. Figure 38C is a diagram showing phase 1 of the DC-DC converter shown in Figures 38A and 38B. Figure 38D is a schematic graph showing the waveform of a ripple current generated in phase 1 of the DC-DC converter.

[0236] As shown in Figure 38C, in phase 1, when a ripple current rp1 is generated in inductor 2a connected to switch element SW1, which is ON, a ripple current rp2 resulting from the ripple current rp1 flows through switch element SW2 via magnetic coupling. These ripple currents rp1 and rp2 are generated so as to reduce the current amplitude of each other. As a result, as shown in Figure 38D, by utilizing magnetic coupling, the current amplitude of the ripple currents rp1 and rp2 generated in each phase can be suppressed compared to when magnetic coupling is not utilized.

[0237] In a typical DC-DC converter, the inductance value must be large to suppress the ripple current below a predetermined value (for example, about 30% of the load current). In contrast, the DC-DC converter shown in Figure 38A can suppress the ripple current as shown in Figure 38D, making it possible to set a smaller inductance value. As a result, inductors 2a and 2b can be made even smaller.

[0238] (Configuration Example (3)) <Inductor Configuration> The circuit board of Configuration Example (3) includes, for example, a plurality of conductor-containing portions, a plurality of first electrodes, and a plurality of second electrodes. These constitute two inductors. Each conductor-containing portion is configured to pass current in the same direction in the Z direction through two conductors arranged in one through hole.

[0239] 39A is a top perspective view schematically showing the conductor-containing portion and second electrode of configuration example (3). FIG. 39B is a bottom perspective view schematically showing the conductor-containing portion and first electrode of configuration example (3). For ease of understanding, the first electrode and second electrode are indicated by two-dot chain lines. Below, differences from configuration example (2) will be mainly described, and overlapping descriptions will be omitted as appropriate.

[0240] In the illustrated example, a plurality of (four in this case) first electrodes 901a, 901bc, 902a, and 902bc are provided on the first surface 811 sides of the conductor-containing portions 802a to 802c. A plurality of (four in this case) second electrodes 911ab, 911c, 912ab, and 912c are provided on the second surface 812 sides of the conductor-containing portions 802a to 802c.

[0241] In this configuration example, the conductors 831 of the conductor-containing portions 802a to 802c are connected in series to form one inductor 2c, and the conductors 832 of the conductor-containing portions 802a to 802c are connected in series to form one inductor 2d.

[0242] Inductor 2c includes conductors 831 of conductor-containing portions 802a to 802c, first electrodes 901a and 901bc, and second electrodes 911ab and 911c. A first end of conductor 831 of conductor-containing portion 802a is electrically connected to a predetermined terminal via first electrode 901a. Second ends of conductors 831 of conductor-containing portions 802a and 802b are electrically connected to each other via second electrode 911ab. First ends of conductors 831 of conductor-containing portions 802b and 802c are electrically connected to each other via first electrode 901bc. Second ends of conductor 831 of conductor-containing portion 802c are electrically connected to a predetermined terminal via second electrode 911c. Inductor 2d has a structure similar to inductor 2b of configuration example (2).

[0243] In the circuit board of the configuration example (3), the conductors 831 and 832 are also electrically separated, so that the conductors 831 and 832 can each constitute a different component (here, inductors 2c and 2d).

[0244] In addition, in the circuit board of configuration example (3), the conductors 831 and 832 are connected to the corresponding electrodes so that the current flows in parallel. With this configuration, the magnetic fields generated by the conductors 831 and 832 have the same direction, which strengthens the magnetic fields. Therefore, the characteristics of the inductor formed by the conductors 831 and 832 can be improved.

[0245] <Circuit Configuration> Fig. 40 is a diagram showing an example of the circuit configuration of a voltage regulation module (step-down DC-DC converter) using the circuit board of configuration example (3). The DC-DC converter shown in Fig. 40 is a multi-phase DC-DC converter including two switch elements SW1 and SW2.

[0246] In this example, two sets of inductors 2c and 2d (hereinafter referred to as "inductor block BL1" and "inductor block BL2") are built into the circuit board. The inductor 2c of the inductor block BL1 is connected between the SW1_Vout terminal of the switch element SW1 and the output terminal Vout. The inductor 2c of the inductor block BL2 is connected between the SW2_Vout terminal of the switch element SW2 and the output terminal Vout. The inductors 2d of the inductor blocks BL1 and BL2 are connected in series with each other between the ground terminal GND.

[0247] The inductors 2c and 2d of each of the inductor blocks BL1 and BL2 have the structures illustrated in Fig. 39A and Fig. 3B. In each of the conductor-containing portions 802a to 802c, current flows in the same direction (parallel) through the conductor 831 that constitutes the inductor 2c and the conductor 832 that constitutes the inductor 2d.

[0248] 40, a component called a trans-inductor-voltage regulator (TLVR) is built into the circuit board, thereby improving the load transient response characteristics. Furthermore, when the two conductors 831, 832 in each of the conductor-containing portions 802a to 802c are arranged close to each other, the conductors 831, 832 are magnetically coupled more strongly, thereby further improving the load transient response characteristics.

[0249] The above effect will be explained in more detail. In a conventional multiphase power supply, an increase or decrease in the load current of the inductor is detected by a change in the FB voltage at the FB terminal. The control IC is configured to correct any excess or deficiency caused by the increase or decrease in current by controlling the duty ratio (ratio of ON time to OFF time) of the signal applied to the control terminals CTL1 and CTL2. In other words, feedback control is performed via the control IC.

[0250] In contrast, in the circuit shown in FIG. 40 , in phase 1, when one of the switch elements (e.g., switch element SW1) is ON, an increase or decrease in the load current of inductor 2c (inductor 2c of inductor block BL1) connected to switch element SW1 is detected by inductor 2d. Then, via magnetic coupling, the inductor 2c of inductor block BL2 supplies a current equal to the increase or decrease. This makes it possible to correct any excess or deficiency of current. In this way, linking the inductors 2c of inductor blocks BL1 and BL2 makes it possible to achieve a high-speed load transient response. This circuit configuration allows for correction of any excess or deficiency due to an increase or decrease in current (feedback application) before feedback control via the control IC, thereby enabling faster operation.

[0251] (Configuration Example (5)) <Inductor Configuration> The circuit board of configuration example (5) includes, for example, a plurality of conductor-containing portions, a plurality of first electrodes, and a plurality of second electrodes. These constitute two inductors. In each conductor-containing portion, three conductors are disposed in one through-hole, and currents are configured to flow in opposite directions (anti-parallel) in the Z direction through two of the conductors and the remaining one conductor.

[0252] 41A is a top perspective view schematically showing the conductor-containing portion and second electrode of configuration example (5). FIG. 41B is a bottom perspective view schematically showing the conductor-containing portion and first electrode of configuration example (5). For ease of understanding, the first electrode and second electrode are indicated by two-dot chain lines. Below, differences from configuration example (2) will be mainly described, and overlapping descriptions will be omitted as appropriate.

[0253] 41A and 41B, a plurality of (here, three) conductor-containing portions 805a to 805c are arranged in this order on the circuit board in the X direction. In each of the conductor-containing portions 802a to 802c, a conductor 832 is located between conductors 831 and 833 in the Y direction.

[0254] In this example, each of the conductor-containing portions 805a to 805c has the same configuration as the conductor-containing portion 805 shown in Figures 36A and 36B. Note that the configuration of these conductor-containing portions is not limited to the example shown in the figures, and may be, for example, the conductor-containing portion 804 shown in Figures 35A and 35B.

[0255] In this example, the circuit board is provided with first electrodes 901ab, 901c, 902a, and 902bc and second electrodes 911a, 911bc, 912ab, and 912c, similar to configuration example (2). The conductors 831 and 832 in each conductor-containing portion are connected to the same electrode and are connected to have the same potential. The conductor 833 in each conductor-containing portion is connected to a different electrode from the other conductors 831 and 832 and is connected to have a different potential.

[0256] In this configuration example, the conductors 831 and 832 of the conductor-containing portions 802a to 802c are connected in series to form one inductor 2e, and the conductor 833 of the conductor-containing portions 802a to 802c is connected in series to form one inductor 2f.

[0257] In inductor 2e, first electrodes 901ab, 901c and second electrodes 911a, 911bc electrically connect conductors 831, 832 of each conductor-containing portion and are arranged to connect in series conductor portions consisting of conductors 831, 832 of conductor-containing portions 802a to 802c, similar to first inductor 2a of configuration example (2). In inductor 2f, first electrodes 902a, 902bc and second electrodes 912ab, 912c are arranged to connect in series conductors 833 of conductor-containing portions 802a to 802c, similar to inductor 2b of configuration example (2).

[0258] In the circuit board of configuration example (5), conductors 831 and 833 and conductor 832 are disposed close to each other within through-hole 820 and are connected to the corresponding electrodes so that the currents flow in antiparallel directions. This causes the magnetic fields generated by conductors 831 and 833 to be in opposite directions to the magnetic field generated by conductor 832. This makes it difficult for magnetic saturation to occur, thereby suppressing degradation of inductor characteristics due to magnetic saturation.

[0259] (Other Configuration Examples) Configuration Example (1) In configuration examples (2) and (3), the conductors 831 and 832 are electrically separated, but they may be electrically connected. For example, the first ends of the conductors 831 and 832 may be electrically connected by a first electrode, and the second ends may be electrically connected by a second electrode (configuration example (1)). In configuration example (1), the potentials and current directions of these conductors are equal to each other.

[0260] In the configuration example (5), the conductors 831 to 833 of each conductor-containing portion are electrically separated into two, but these three conductors do not have to be electrically separated. For example, the first ends of the three conductors may be electrically connected to each other by a first electrode, and the second ends may be electrically connected to each other by a second electrode (configuration example (4)). In the configuration example (4), the potentials and current directions of these conductors are equal to each other.

[0261] Configuration example (6) In configuration example (5), the conductors 831 to 833 of each conductor-containing portion are electrically separated into two, and the directions of the two currents (i.e., the direction of the current flowing through the conductors 831 and 832 and the direction of the current flowing through the conductor 833) are antiparallel, but the directions of these currents may also be parallel (configuration example (6)).

[0262] Configuration examples (7) and (8) In configuration example (5), of the conductors 831 to 833 of each conductor-containing portion, the conductors 831 and 832 have the same potential V1, and the conductor 833 has a different potential V2, but the conductors 831 and 833 may have the same potential V1, and the central conductor 832 may have a different potential V2. In this case, the direction of the current in the conductors 831 and 833 and the direction of the current in the conductor 832 may be antiparallel (configuration example (7)) or parallel (configuration example (8)).

[0263] Configuration Examples (9) to (11) The conductors 831 to 833 of each conductor-containing portion may be electrically isolated from one another (i.e., three separate conductors). In this case, the currents in the conductors 831 to 833 may all be parallel (parallel) (Configuration Example (9)). Alternatively, the conductors 831 and 832 may be configured so that current flows in the same direction, while the conductor 833 flows in the opposite direction (anti-parallel) to the conductors 831 and 832 (Configuration Example (10)). Furthermore, the conductors 831 and 833 at both ends may be configured so that current flows in the same direction, while the central conductor 832 flows in the opposite direction (anti-parallel) to the conductors 831 and 833 at both ends (Configuration Example (11)). In Configuration Examples (10) and (11), the magnetic fields generated by two of the three electrically independent conductors 831 to 833 are in the same direction, and the magnetic field generated by the remaining conductor is in the opposite direction (anti-mixed).

[0264] The configuration of the circuit board of this embodiment is not limited to the configuration described above. In Table 1, the number of conductors is two or three, but it may be four or more. Also, although an example including three conductor-containing portions is shown in FIGS. 37A to 41B, the circuit board of this embodiment may include at least one conductor-containing portion, and the number of conductor-containing portions is not particularly limited. Furthermore, the circuit board of this embodiment may include a mixture of conductor-containing portions with different configurations (e.g., different numbers or shapes of conductors).

[0265] Furthermore, the positions, shapes, cross-sectional areas, and electrode positions and shapes of conductors 831-833 are not limited to the illustrated examples and can be appropriately set depending on the design of the circuit board. In FIGS. 30 to 41B, conductors 831-833 are all rectangular prisms, but they may be other polygonal prisms. Alternatively, the conductors may be cylindrical, semi-cylindrical, elliptical, or semi-elliptical. For example, in the examples shown in FIGS. 30 to 33B, conductors 831 and 832 have the same cross-sectional area, but these cross-sectional areas may be different from each other. In the examples shown in FIGS. 35A to 36B, conductors 831 and 833 have the same cross-sectional area and shape, but these may be different from each other. Furthermore, conductors 831 and 832 are arranged symmetrically across conductor 832 in a plan view, but they may also be asymmetric.

[0266] The configuration of the DC-DC converter using the circuit board of this embodiment is not limited to the configurations exemplified in FIGS. 38A and 40 . In FIG. 38A , a circuit board of configuration example (2) is used, but other configurations in which the current directions of the two conductors in the through-hole are parallel may be used instead. In FIG. 40 , a circuit board of configuration example (3) is used, but other configurations in which the current directions of the two conductors in the through-hole are antiparallel may be used instead. The circuit configuration and the number of switch elements are also not limited to the examples shown. Furthermore, the DC-DC converter shown in FIG. 6 may be configured using circuit boards of configuration examples (1) and (4).

[0267] Furthermore, although the above description has been given taking the conductor-containing portion constituting an inductor as an example, the conductor-containing portion may also constitute a component other than an inductor.

[0268] [Method for Manufacturing Conductor-Containing Portion] A method for manufacturing the conductor-containing portion in this embodiment will be described. Here, the case of manufacturing a first structure M having a conductor 831 with a rectangular cross section and a conductor 832 with a trapezoidal cross section, similar to the conductor-containing portion 803 shown in Figures 34A and 34B, will be described as an example.

[0269] (Manufacturing of First Structure M) FIGS. 42A to 42E are schematic perspective views illustrating steps in a manufacturing method for the first structure M. First, as shown in FIG. 42A , a first metal foil (e.g., copper foil) 8310 that will become the conductor 831 and a second metal foil (e.g., copper foil) 8320 that will become the conductor 832 are stacked via an adhesive layer (e.g., an adhesive sheet) 8400 that will become the isolation insulating layer 840 to form a laminate 8000. Next, as shown in FIG. 42B , the first metal foil 8310 and / or the second metal foil 8320 are processed (etched). Here, multiple grooves 8311 extending in one direction (the Z direction in this figure) are formed in the first metal foil 8310, separating the first metal foil 8310 into multiple portions 8312. Each portion 8312 is a quadrangular prism with a trapezoidal cross section. Although not shown, an insulating film that will become the insulating layer 850 may be formed on the upper and lower surfaces of the processed laminate 8000. 43C, the laminated body 8000 is cut in a direction intersecting (here, perpendicular to) the upper surface of the laminated body 8000. In this manner, a plurality of first structures M are obtained.

[0270] (Manufacturing of Conductor-Containing Portion) FIG. 43A is a schematic perspective view showing the steps of a manufacturing method of the conductor-containing portion. As shown in FIG. 43A, a substrate (e.g., a magnetic material) 810 having a through hole 820 is prepared. The width of the substrate 810 in the X direction is, for example, 4.0 mm, and the width in the Y direction is, for example, 3.0 mm. The through hole 820 is obtained, for example, by drilling a cylindrical through hole (first hole) with a radius d1 and a cylindrical through hole (second hole) with a radius d2 so that they partially overlap each other. In this example, multiple (here, three) through holes 820 are arranged in the substrate 810 at a distance (e.g., 0.75 mm) in the X direction.

[0271] Next, the first structures M manufactured by the above method are inserted into each through-hole 820 of the substrate 810. After this, the first structures M are sealed. Here, a resin member that becomes the insulating portion 860 is formed in the gap between the first structures M and the inner wall of the through-hole 820, and a sealing insulating layer that covers the lower and upper surfaces of each conductor is formed. Next, via holes are formed in the sealing insulating layer, and via conductors are formed in the via holes.

[0272] Fig. 43B is a perspective view showing the first structure M in which via conductors are formed. In Fig. 43B, the sealing insulating layer is not shown.

[0273] 43B , multiple via conductors 830 are formed at a distance from each other on first and second end surfaces of conductors 831 and 832. The first and second end surfaces of conductors 831 and 832 are surfaces located on the first surface 811 and second surface 812 sides (see FIG. 34B ) of substrate 810, respectively. The thickness h1 of conductors 831 and 832 in the Z direction is determined by the thickness of substrate 810 and is, for example, 0.8 mm. The width t1 of isolation insulating layer 840 is adjusted by the thickness of adhesive layer 8400 shown in FIG. 42A and is, for example, 0.015 mm.

[0274] Thereafter, electrodes (corresponding to the electrodes 31 and 32 in the above-described embodiment) may be formed on the via conductors as needed. An electrode may be provided for each conductor. In this manner, the conductor-containing portion is manufactured.

[0275] The substrate 810 with the three conductor-containing portions formed thereon may be placed in the opening of the core substrate 10 (see FIG. 3A ). Alternatively, the substrate 810 may be divided into individual conductor-containing portions, which are then placed in the opening of the core substrate. In this manner, a component-embedded substrate is obtained. Thereafter, a circuit board can be manufactured by forming wiring structures on both sides of the component-embedded substrate, as in the previously described embodiment.

[0276] (Design Method) FIGS. 44A and 44B are diagrams for explaining an example of a design method for the first structure M, and are each a schematic top view of the first structure M.

[0277] The lengths of conductors 831 and 832 in the X and Y directions are designed to facilitate the formation of a magnetic field in each conductor 831 and 832 and to increase the cross-sectional area. Hereinafter, the relationship between the lengths of conductors 831 and 832 in the X and Y directions and the opening shape of through-hole 820 will be described with reference to Fig. 44A .

[0278] 44A , the through-hole 820 has a structure in which a cylindrical first hole with a radius d1 and a cylindrical second hole with a radius d2 are arranged so as to partially overlap each other. A first region Pc1 defined by the inner wall of the first hole and a second region Pc2 defined by the inner wall of the second hole are in communication with each other. In a plan view, the radii d1 and d2 and the distance d3 between the center of the first hole and the center of the second hole are set to satisfy, for example, the following relationship: (d3) ２ ≦(d1) ２ + (d2) ２ As a result, in a plan view, the angle α formed by the tangent to the inner wall of the first hole and the tangent to the inner wall of the second hole at the point where the inner wall of the first hole intersects with the inner wall of the second hole is not an acute angle, thereby reducing magnetic resistance and increasing magnetic coupling between conductors 831 and 832. In this example, radius d2 is greater than radius d1 (d2 > d1). Radius d1 is, for example, 0.5 mm, and radius d2 is, for example, 0.65 mm.

[0279] In a plan view, the conductor 832 has a polygonal shape that is slightly smaller than the polygon inscribed in the second region Pc2, which is a partial circle. The polygon is, for example, an n-sided polygon (n is 4 or more). This allows the conductor 832 to be disposed inside the second region Pc2 of the through-hole 820.

[0280] 44A , the conductor 832 is, for example, rectangular in plan view. The length u2 of the conductor 832 in the Y direction is adjusted by the thickness of the second metal foil 8320 ( FIG. 42A ) and is, for example, 0.8 mm. The width w3 of the conductor 832 in the X direction is adjusted by etching and is, for example, 1.0 mm.

[0281] In plan view, the conductor 831 has a polygonal shape with two vertices close to the -Y side of the conductor 832 (the side closest to the first region Pc1). The polygon is, for example, an n-sided polygon (n is 4 or greater). In plan view, the vertex of the polygon of the conductor 831 that is farthest from the conductor 832 may be located slightly inside a point on the arc of the first region Pc1, which is a partial circle. This allows the cross-sectional area of ​​the conductor 831 to be increased while the conductor 832 is disposed inside the second region Pc2.

[0282] In FIG. 44A , in a plan view, the conductor 831 is trapezoidal, with its lower base located on the conductor 832 side, and the two vertices on both sides of the upper base of the trapezoid are located slightly inside the arc of the partially circular first region Pc1. The length u1 of the conductor 831 in the Y direction is adjusted by the thickness of the first metal foil 8310 ( FIG. 42A ) and is, for example, 0.8 mm. The widths w1 and w2 of the conductor 831 in the X direction can be adjusted by etching. The width w1 (the length of the lower base of the trapezoid) is, for example, 0.7 mm. The width w2 (the length of the upper base of the trapezoid) is, for example, 0.5 mm. The base angles at both ends of the lower base of the trapezoid can be adjusted to a desired angle (acute angle) by the etching method and etching conditions. In this example, the lengths u1 and u2 are equal, but they may also be different.

[0283] Next, referring to FIG. 44B , an example of the size and arrangement of the via conductors 830 will be described. Here, one end of each via conductor 830 is connected to the end face (first end face or second end face) of the conductors 831 and 832. The via conductors 830 are cylindrical with a radius d4 and extend in the Z direction away from the end faces of the conductors 831 and 832. Adjacent via conductors 830 are spaced apart by at least a distance d5. As an example, the positions and number of the via conductors 830 may be determined by arranging concentric circles, each consisting of a circle with a radius d4 and a virtual circle 830i with a radius of d4 + d5, on the end faces of the conductors 831 and 832 in a plan view. This allows multiple via conductors 830 to be more densely arranged on the first end faces of the conductors 831 and 832 while maintaining a predetermined spacing (distance d5). The radius d4 of the cylindrical via conductor 830 is, for example, 0.0575 mm. The distance d5 is, for example, 0.05 mm.

[0284] In the above method, a first structure M including a plurality of conductors 831, 832 separated by a separation insulating layer 840 is placed in one through hole 820 of a substrate 810. By placing a separately manufactured first structure M in the through hole of the substrate 810, the plurality of conductors 831, 832 can be more easily placed in the through hole 820 at a predetermined distance. In addition, it is easy to control the distance between the conductors 831, 832, the positional relationship between the conductors 831, 832, and the like.

[0285] In the above method, the through hole 820 and the first structure M may have a planar shape that is long in one direction or an asymmetric shape. This makes it easier to arrange the multiple conductors 831, 832 in the through hole 820 in a predetermined orientation. This is advantageous because it eliminates the need for a structure or process for alignment.

[0286] The method for manufacturing the circuit board of this embodiment is not limited to the above method. For example, a plurality of columnar conductors (e.g., cylindrical Cu pins) whose peripheral surfaces are covered with an insulating layer may be prepared and placed in a single through-hole in the substrate. After this, the area of ​​the through-hole where the plurality of conductors are not placed may be filled with resin or the like.

[0287] Fourth Embodiment A fourth embodiment is a voltage regulation module including a circuit board with a built-in inductor. The following description will be given taking as an example a case where the circuit board 1 shown in FIGS. 1 and 2 is used as the circuit board with a built-in inductor.

[0288] 45 is a schematic cross-sectional view showing an example of a voltage regulation module 400 according to the fourth embodiment. The voltage regulation module 400 is a step-down converter having the circuit configuration described above with reference to FIG. 6, for example.

[0289] The voltage regulation module 400 is disposed, for example, on a main surface 500s of a system board (motherboard) 500. A power management IC (PMIC) may also be disposed on the main surface 500s. Although not shown, a processing unit may also be disposed on the opposite main surface of the system board 500.

[0290] The voltage regulation module 400 includes a circuit board 1 with a built-in inductor and a switch element SW.

[0291] The circuit board 1 is the same as the circuit board 1 in the above-described embodiment. The circuit board 1 has an inductor 2 and a two-terminal capacitor (an input capacitor, an output capacitor, etc.) built in. The circuit board 1 is disposed such that a first main surface s1 on which terminal portions such as an input terminal Vin and an output terminal Vout are disposed faces a main surface 500s of the system board 500.

[0292] The switch element SW is disposed on the second main surface s2 of the circuit board 1. The switch element SW includes high-side and low-side MOSFETs and a plurality of terminals (see FIG. 6). Each terminal of the switch element SW is connected to a corresponding land on the second main surface s2 of the circuit board 1.

[0293] In the voltage regulation module 400 of this embodiment, components such as the inductor 2 and the two-terminal capacitor are arranged in parallel within the circuit board 1. Furthermore, the inductor 2 is divided into multiple parts and built into the circuit board 1. This allows the voltage regulation module 400 to be made thinner.

[0294] Furthermore, in the voltage regulation module 400 of this embodiment, the output end p1 of the inductor 2 is located on the first main surface s1 side. This allows for a shorter path between the output end p1 of the inductor 2 and the output terminal Vout. Furthermore, since the input end p2 of the inductor 2 is located on the second main surface s2 side, this allows for a shorter path between the input end p2 of the inductor 2 and the switch output terminal SW_Vout of the switch element SW. This further reduces the electrical resistance from the switch output terminal SW_Vout of the switch element SW to the output terminal Vout. This makes it possible to provide a more efficient voltage regulation module 400.

[0295] The configuration and layout of the voltage regulation module of this embodiment are not limited to the example shown in FIG. 45 . Any of the circuit boards exemplified in the first to third embodiments can be used as the circuit board. The voltage regulation module of this embodiment only needs to be configured so that the inductor built into the circuit board of this embodiment is connected between the output terminal of the switch element and the output terminal of the module. Furthermore, although the circuit board with an inductor built into the circuit board of this embodiment is applied to a buck converter in this embodiment, it can also be applied to other regulators such as a boost or buck-boost converter.

[0296] The present disclosure is not limited to the above-described embodiments, and design modifications are possible within the scope of the present disclosure. Furthermore, by appropriately combining the configurations of any of the various exemplary embodiments (including modified examples), the effects of each embodiment can be achieved.

[0297] The circuit board with built-in inductor of the present disclosure can also be expressed as follows.

[0298] A circuit board with an inductor of a first aspect comprises: a substrate having a first surface and a second surface located opposite to the first surface in a thickness direction; a first wiring layer arranged on the first surface of the substrate via a first insulating portion; a second wiring layer arranged on the second surface of the substrate via a second insulating portion; and an inductor located inside the substrate, wherein the inductor comprises: a first conductor, a second conductor, and a third conductor arranged within the substrate at a distance from each other in a plan view seen along the thickness direction and extending in the thickness direction; a first magnetic body located around the first conductor so as to surround the circumferential surface of the first conductor; a second magnetic body located around the second conductor so as to surround the circumferential surface of the second conductor; and a third magnetic body located around the third conductor so as to surround the circumferential surface of the third conductor, Each of the first conductor, the second conductor, and the third conductor has a first end located on the first surface side and a second end located on the second surface side within the substrate; the first wiring layer has a first connection electrode that electrically connects the first ends of the first conductor and the second conductor to each other; the second wiring layer has a second connection electrode that electrically connects the second ends of the second conductor and the third conductor to each other; the first ends of the first conductor and the second conductor are electrically connected to the first connection electrode through via conductors arranged within the first insulating portion; and the second ends of the second conductor and the third conductor are electrically connected to the second connection electrode through via conductors arranged within the second insulating portion.

[0299] A second aspect of the circuit board with an inductor is the circuit board with an inductor of the first aspect, wherein the first conductor, the second conductor, and the third conductor are connected in series, one of the input end and the output end of the inductor is connected to wiring in the first wiring layer through a via conductor arranged in the first insulating portion, and the other of the input end and the output end of the inductor is connected to wiring in the second wiring layer through a via conductor arranged in the second insulating portion.

[0300] A third aspect of the circuit board with an inductor is a circuit board with an inductor of the first or second aspect, wherein the inductor is located within the substrate on the first surface side of the first end of the first conductor and has a first electrode electrically connected to the first conductor, and when viewed in a plan view along the thickness direction, the first electrode is arranged to overlap the entire first conductor and at least a portion of the first magnetic body.

[0301] A fourth aspect of the circuit board with an inductor is the circuit board with an inductor of the third aspect, wherein the first electrode of the first conductor is electrically connected to the first connection electrode through a plurality of via conductors arranged in the first insulating portion, and in a planar view along the thickness direction, at least one of the plurality of via conductors is located outside the first conductor.

[0302] A fifth aspect of the circuit board with an inductor is a circuit board with an inductor according to any one of the first to fourth aspects, which has at least one two-terminal capacitor located inside the substrate, and the at least one two-terminal capacitor and the inductor are arranged in parallel in a direction intersecting the thickness direction.

[0303] A sixth aspect of the circuit board with an inductor is the circuit board with an inductor of the fifth aspect, wherein the at least one two-terminal capacitor comprises a dielectric, a lower electrode located on the first surface side of the dielectric, and an upper electrode located on the second surface side of the dielectric, the lower electrode being electrically connected to wiring in the first wiring layer through a via conductor provided in the first insulating portion, and the upper electrode being electrically connected to wiring in the second wiring layer through a via conductor provided in the second insulating portion.

[0304] A seventh aspect of the circuit board with built-in inductor is the circuit board with built-in inductor of any one of the first to sixth aspects, wherein the first magnetic body, the second magnetic body, and the third magnetic body are integrally formed.

[0305] An eighth aspect of the circuit board with an inductor is the circuit board with an inductor of the seventh aspect, wherein the inductor has, inside the substrate, a first electrode electrically connected to the first end of the first conductor, a second electrode electrically connected to the first end of the second conductor, a third electrode electrically connected to the second end of the second conductor, and a fourth electrode electrically connected to the second end of the third conductor, wherein the first electrode and the second electrode are integrally formed, and the third electrode and the fourth electrode are integrally formed.

[0306] A voltage regulation module of a ninth aspect includes: an inductor-built-in circuit board according to any one of the first to eighth aspects; an input terminal and an output terminal; and a switch element connected between the input terminal and the inductor.

[0307] A tenth aspect of the voltage regulation module is the voltage regulation module of the ninth aspect, wherein the circuit board with an inductor has a first main surface located on the first surface side of the base material, and a second main surface located on the second surface side of the base material, on which the input terminal and the output terminal are arranged, and the switch element is arranged on the first main surface.

[0308] The circuit board with built-in conductors of the present disclosure can also be expressed as follows.

[0309] A first aspect of the circuit board with built-in conductors comprises: a substrate having a first surface, a second surface located on the opposite side of the first surface in the thickness direction from the first surface, and a through hole extending in the thickness direction; a first wiring layer arranged on the first surface of the substrate; a second wiring layer arranged on the second surface of the substrate; and a first conductor and a second conductor arranged in the through hole, each extending in the thickness direction, and further comprising an isolation insulating layer located in the through hole between the first conductor and the second conductor in a planar view seen along the thickness direction, and separating the first conductor from the second conductor.

[0310] A second aspect of the circuit board with built-in conductors is the circuit board with built-in conductors of the first aspect, wherein the first conductor and the second conductor are electrically separated.

[0311] A circuit board with built-in conductors of a third aspect is the circuit board with built-in conductors of the second aspect, wherein currents flow through the first conductor and the second conductor in opposite directions in the thickness direction.

[0312] A fourth aspect of the circuit board with built-in conductors is the circuit board with built-in conductors of the second aspect, wherein currents flow in the same direction in the thickness direction through the first conductor and the second conductor.

[0313] A fifth aspect of the circuit board with built-in conductors is the circuit board with built-in conductors of the first aspect, wherein the first conductor and the second conductor are electrically connected.

[0314] A sixth aspect of the circuit board with built-in conductors is a circuit board with built-in conductors according to any one of the first to fifth aspects, wherein, in a plan view seen along the thickness direction, the first conductor and the second conductor face each other in a first direction with the isolation insulating layer sandwiched therebetween, and the width of the first conductor in a second direction perpendicular to the first direction decreases with increasing distance from the second conductor along the first direction.

[0315] A seventh aspect of the circuit board with built-in conductors is the circuit board of any one of the first to sixth aspects, wherein the through holes have a shape that is elongated in one direction in a plan view seen along the thickness direction.

[0316] An eighth aspect of the circuit board with built-in conductors is the circuit board with built-in conductors of the seventh aspect, wherein the first conductor, the second conductor, and the isolation insulating layer constitute a first structure, and when viewed in a plan view along the thickness direction, the first structure has a shape that is long in one direction, and when viewed in a plan view along the thickness direction, the first structure is arranged inside the through hole so that the longitudinal direction of the first structure coincides or approximately coincides with the longitudinal direction of the through hole.

[0317] A ninth aspect of the circuit board with built-in conductors is a circuit board with built-in conductors according to any one of the first to fourth aspects, further comprising a first inductor and a second inductor between the first wiring layer and the second wiring layer, the first inductor comprising the first conductor, and the second inductor comprising the second conductor.

[0318] A circuit board with built-in conductors of a tenth aspect is a circuit board with built-in conductors of any one of the first to ninth aspects, wherein the first conductor and the second conductor each have a first end located on the first surface side and electrically connected to one of the electrodes in the first wiring layer, and a second end located on the second surface side and electrically connected to one of the electrodes in the second wiring layer.

[0319] The conductor-embedded circuit board of an eleventh aspect is a conductor-embedded circuit board of any one of the conductor-embedded circuit boards of the first to tenth aspects, further comprising a third conductor disposed within the through hole and extending in the thickness direction, wherein, in a plan view seen along the thickness direction, the third conductor is disposed within the through hole at a distance from the first conductor and the second conductor.

[0320] A twelfth aspect of the circuit board with built-in conductors is the circuit board with built-in conductors of the eleventh aspect, wherein, in a plan view seen along the thickness direction, the second conductor is located between the first conductor and the third conductor in a first direction, and the isolation insulating layer includes a first isolation insulating layer located between the first conductor and the second conductor, and a second isolation insulating layer located between the second conductor and the third conductor.

[0321] A thirteenth aspect of the circuit board with built-in conductors is the circuit board with built-in conductors of the twelfth aspect, wherein, in a planar view along the thickness direction, the width of the first conductor in a second direction perpendicular to the first direction decreases with increasing distance from the second conductor along the first direction, and the width of the third conductor in the second direction decreases with increasing distance from the second conductor along the first direction.

[0322] A conductor-embedded circuit board of a 14th aspect is a conductor-embedded circuit board of any one of the 11th to 13th aspects, wherein the first conductor and the second conductor are electrically connected, and the third conductor is electrically separated from the first conductor and the second conductor.

[0323] A 15th aspect of the circuit board with built-in conductors is the 14th aspect of the circuit board with built-in conductors, configured such that current flows through the first conductor and the second conductor in the same direction in the thickness direction, and current flows through the third conductor in the opposite direction to that of the first conductor and the second conductor.

[0324] A 16th aspect of the circuit board with built-in conductors is the 14th aspect of the circuit board with built-in conductors, wherein current flows through the first conductor, the second conductor, and the third conductor in the same direction in the thickness direction.

[0325] A circuit board with built-in conductors of a seventeenth aspect is the circuit board with built-in conductors of any one of the eleventh to thirteenth aspects, wherein the first conductor, the second conductor, and the third conductor are electrically isolated from each other.

[0326] The conductor-embedded circuit board of the 18th aspect is the conductor-embedded circuit board of the 17th aspect, configured such that current flows through the first conductor and the second conductor in the same direction in the thickness direction, and current flows through the third conductor in the opposite direction to that of the first conductor and the second conductor.

[0327] A nineteenth aspect of the circuit board with built-in conductors is the seventeenth aspect of the circuit board with built-in conductors, wherein the first conductor, the second conductor, and the third conductor are configured so that current flows in the same direction in the thickness direction.

[0328] A 20th aspect of the circuit board with built-in conductors is the circuit board with built-in conductors of any one of the 11th to 13th aspects, wherein the first conductor, the second conductor, and the third conductor are electrically connected.

[0329] A 21st aspect of the circuit board with built-in conductors is the circuit board with built-in conductors of the 9th aspect, which comprises a plurality of conductor-containing portions each having the substrate, the first conductor, the second conductor, and the isolation insulating layer, wherein the first conductors in the plurality of conductor-containing portions are connected in series to form the first inductor, and the second conductors in the plurality of conductor-containing portions are connected in series to form the second inductor.

[0330] The circuit board with built-in conductors according to the present invention can be miniaturized, and therefore can be suitably applied to various devices such as voltage regulation modules.

[0331] 1 Circuit board (circuit board with built-in inductor) 2, 2a to 2f Inductor 3, 3a to 3c Conductor 4, 4a to 4c Magnetic body 4L Magnetic body layer 5 Input capacitor 6 Output capacitor 7, 71 to 73 Core through conductor 8 Sealing member 10 Base material (core base material) 11 First surface 12 Second surface 13a to 13c, 14 to 16 Through hole (core through hole) 20, 20a to 20c Inductor unit cell 21 First cell insulating part 22 Second cell insulating part 23 Insulating part 24, 25 Sealing insulating layer 31, 31a to 31c, 31ab First electrode 32, 32a to 32c, 32bc Second electrode 41 Magnetic body through hole 51, 61 Lower electrode 52, 62 Upper electrode 53 Dielectric 81 Lower insulating layer 82 Upper insulating layer 83 Insulating portion 91 First insulating portion 92 Second insulating portion 100 First wiring structure 101 to 103, 201 to 203 Insulating layer 105, 205 Solder resist layer 110, 120, 130, 210, 220, 230 Wiring layer 111 First connection electrode 112 First inductor connection electrode 113 First input capacitor connection electrode 200 Second wiring structure 211 Second inductor connection electrode 212 Second connection electrode 213 Second input capacitor connection electrode 214 Output capacitor connection electrode 300, 300a Component-embedded substrate 400 Voltage regulation module 410, 420 MOSFET 500 System board 800 to 805, 802a to 802c, 805a to 805c Conductor-containing portion 811 First surface 812 Second surface 810 Base material 820 Through hole 830 Via conductor 831 to 833 Conductors 831a, 832a, 833a First side surface 831b, 832b Second side surface 840 Isolation insulating layer 841 First isolation insulating layer 842 Second isolation insulating layer 850 Insulating layer 860 Insulating portion 901a, 901ab, 901bc, 901c, 902a, 902bc First electrode 911a, 911ab, 911bc, 911c, 912ab, 912c Second electrode M First structure CTL Control terminal e1 First end face e2 Second end face r1 Inductor arrangement region r2 Capacitor arrangement region r3 Through-core conductor arrangement regionSW, SW1, SW2 switch elements

Claims

1. A circuit board with built-in conductors comprising: a substrate having a first surface, a second surface located on the opposite side of the first surface in a thickness direction, and a through hole extending in the thickness direction; a first wiring layer arranged on the first surface of the substrate; a second wiring layer arranged on the second surface of the substrate; and a first conductor and a second conductor arranged in the through hole, each extending in the thickness direction, and further comprising an isolation insulating layer located in the through hole between the first conductor and the second conductor in a planar view along the thickness direction, separating the first conductor and the second conductor.

2. The circuit board with built-in conductors according to claim 1, wherein the first conductor and the second conductor are electrically isolated from each other.

3. The circuit board with built-in conductors according to claim 2, wherein currents flow through the first conductor and the second conductor in opposite directions in the thickness direction.

4. The circuit board with built-in conductors according to claim 2, wherein the first conductor and the second conductor are configured so that currents flow in the same direction in the thickness direction.

5. The circuit board with built-in conductors according to claim 1, wherein the first conductor and the second conductor are electrically connected.

6. A circuit board with built-in conductor as described in any one of claims 1 to 5, wherein, in a plan view along the thickness direction, the first conductor and the second conductor face each other in a first direction with the isolation insulating layer sandwiched between them, and the width of the first conductor in a second direction perpendicular to the first direction decreases with increasing distance from the second conductor along the first direction.

7. The circuit board with built-in conductors according to claim 1, wherein, in a plan view taken along the thickness direction, the through hole has a shape that is elongated in one direction.

8. A circuit board with built-in conductor as described in claim 7, wherein the first conductor, the second conductor and the isolation insulating layer constitute a first structure, and in a plan view seen along the thickness direction, the first structure has a shape that is elongated in one direction, and in a plan view seen along the thickness direction, the first structure is disposed inside the through hole such that the longitudinal direction of the first structure coincides or approximately coincides with the longitudinal direction of the through hole.

9. A circuit board with built-in conductors as described in any one of claims 1 to 4, further comprising a first inductor and a second inductor between the first wiring layer and the second wiring layer, the first inductor comprising the first conductor, and the second inductor comprising the second conductor.

10. A circuit board with built-in conductors as described in any one of claims 1 to 9, wherein each of the first conductor and the second conductor has a first end located on the first surface side and electrically connected to one of the electrodes in the first wiring layer, and a second end located on the second surface side and electrically connected to one of the electrodes in the second wiring layer.

11. A circuit board with built-in conductor as described in any one of claims 1 to 10, further comprising a third conductor disposed within the through hole and extending in the thickness direction, wherein, in a plan view seen along the thickness direction, the third conductor is disposed within the through hole at a distance from the first conductor and the second conductor.

12. The circuit board with built-in conductors as described in claim 11, wherein, in a plan view seen along the thickness direction, the second conductor is located between the first conductor and the third conductor in a first direction, and the isolation insulating layer includes a first isolation insulating layer located between the first conductor and the second conductor, and a second isolation insulating layer located between the second conductor and the third conductor.

13. A circuit board with built-in conductors as described in claim 12, wherein, in a plan view along the thickness direction, the width of the first conductor in a second direction perpendicular to the first direction decreases with increasing distance from the second conductor along the first direction, and the width of the third conductor in the second direction decreases with increasing distance from the second conductor along the first direction.

14. A circuit board with built-in conductors according to any one of claims 11 to 13, wherein the first conductor and the second conductor are electrically connected, and the third conductor is electrically isolated from the first conductor and the second conductor.

15. A circuit board with built-in conductors as described in claim 14, wherein current flows in the same direction in the thickness direction in the first conductor and the second conductor, and current flows in the opposite direction in the third conductor to that in the first conductor and the second conductor.

16. The circuit board with built-in conductors according to claim 14, wherein the first conductor, the second conductor and the third conductor are configured so that current flows in the same direction in the thickness direction.

17. The circuit board with built-in conductors according to any one of claims 11 to 13, wherein the first conductor, the second conductor, and the third conductor are electrically isolated from each other.

18. A circuit board with built-in conductors as described in claim 17, wherein current flows in the same direction in the thickness direction in the first conductor and the second conductor, and current flows in the opposite direction in the third conductor to the first conductor and the second conductor.

19. The circuit board with built-in conductors according to claim 17, wherein the first conductor, the second conductor and the third conductor are configured so that current flows in the same direction in the thickness direction.

20. The circuit board with built-in conductors according to any one of claims 11 to 13, wherein the first conductor, the second conductor, and the third conductor are electrically connected to each other.

21. A circuit board with built-in conductors as described in claim 9, comprising a plurality of conductor-containing portions each having the substrate, the first conductor, the second conductor, and the isolation insulating layer, wherein the first conductors in the plurality of conductor-containing portions are connected in series to form the first inductor, and the second conductors in the plurality of conductor-containing portions are connected in series to form the second inductor.

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