Wiring substrate with inductor function and method for manufacturing the same

Abstract

The present application provides a wiring substrate with an inductor structure built-in, and a manufacturing method thereof. The wiring substrate has excellent planar direction insulation, and has a magnetic body inside and outside a conductor coil, thus providing excellent inductive characteristics. A wiring substrate with an inductor function includes: an inner layer substrate having a first main surface and a second main surface, and formed with an opening through the first and second main surfaces; a magnetic body layer, which is a magnetic body layer disposed inside the opening, and formed with a first through-hole through the first and second main surfaces thereof; an insulator, which is an insulator disposed inside the first through-hole, and formed with a second through-hole through the insulator; and an inductor formed by a first conductor pattern formed on the first main surface of the magnetic body layer, a second conductor pattern formed on the second main surface of the magnetic body layer, and a through-hole conductor disposed inside the second through-hole and connecting the first and second conductor patterns.

Description

TECHNICAL FIELD

[0001] The present application relates to a wiring substrate having an inductor function and a manufacturing method thereof. Specifically, the present application relates to a wiring substrate having an inductor structure built therein and a manufacturing method thereof. BACKGROUND

[0002] Inductors are mounted in large quantities in high-function electronic devices such as portable telephones, smartphones, tablet PCs, and the like. In the case where an inductor component is installed or embedded in a wiring substrate to build an inductor component therein, the inductor component described in Patent Documents 1 and 2, for example, can be used.

[0003] In recent years, electronic devices are being increasingly downsized, and wiring substrates for such small electronic devices are required to be further high-functional and small-sized. For inductors, in addition to the technology of using a separate inductor component, or instead of the technology of using a separate inductor component, a technology of building an inductor structure in a wiring substrate is expected.

[0004] As a technology of building an inductor structure in a wiring substrate, for example, based on the manufacturing method of the inductor component of Patent Document 2, a method of using a magnetic sheet as an inner layer substrate, forming a solenoid-shaped conductor pattern on the magnetic sheet, and forming an inductor structure can be considered. Further, as proposed in Patent Document 3, a method of housing a magnetic body in a partial region of an insulating substrate and performing an operation of providing a via conductor or the like of the insulating substrate around the magnetic body to form a solenoid-shaped conductor pattern and form an inductor structure can also be considered.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-197624

[0008] Patent Document 2: Japanese Patent Application Publication No. 2014-116465

[0009] Patent Document 3: Japanese Patent Application Publication No. 2016-39256 SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] However, the method of using a magnetic sheet as an inner layer substrate and forming a solenoid-shaped conductor pattern on the magnetic sheet lacks insulation in the planar direction (the main surface direction of the substrate), and it is difficult to obtain the expected inductive characteristics (inductance characteristics).

[0012] Further, in a method of receiving a magnetic body in a partial region of an insulating substrate and forming a solenoid-shaped conductor pattern by providing a via conductor or the like in the insulating substrate around the magnetic body, although the magnetic body exists inside the solenoid-shaped conductor pattern (conductor coil), the magnetic body does not exist outside the conductor coil, so it is difficult to obtain desired inductive characteristics.

[0013] The present application provides a wiring substrate with an inductor structure and a manufacturing method thereof, which has excellent planar direction insulation, and has excellent inductive characteristics because a magnetic body exists not only inside a conductor coil but also outside the conductor coil.

[0014] Technical solution adopted to solve the technical problem

[0015] The present application includes the following,

[0016] [1] A wiring substrate with an inductor function, comprising:

[0017] an inner layer substrate having a first main surface and a second main surface, and formed with an opening passing through the first main surface and the second main surface;

[0018] a magnetic body layer, which is a magnetic body layer provided inside the opening, and formed with a first via passing through the first main surface and the second main surface thereof;

[0019] an insulator, which is an insulator provided inside the first via, and formed with a second via passing through the insulator; and

[0020] an inductor formed by a first conductor pattern formed on the first main surface of the magnetic body layer, a second conductor pattern formed on the second main surface of the magnetic body layer, and a via conductor provided inside the second via and connecting the first conductor pattern and the second conductor pattern;

[0021] [2] The wiring substrate according to [1], further comprising an insulating layer provided in conjunction with the first main surface of the inner layer substrate and the first main surface of the magnetic body layer,

[0022] the first conductor pattern is provided on the first main surface of the magnetic body layer in conjunction with the surface of the insulating layer;

[0023] [3] The wiring substrate according to [1] or [2], further comprising an insulating layer provided in conjunction with the second main surface of the inner layer substrate and the second main surface of the magnetic body layer,

[0024] the second conductor pattern is provided on the second main surface of the magnetic body layer in conjunction with the surface of the insulating layer;

[0025] [4] The wiring substrate according to [2] or [3], wherein the conductor layer provided on at least one of the first main surface and the second main surface of the inner layer substrate so as to be joined to the surface of the insulating layer;

[0026] [5] The wiring substrate according to any one of [1] to [4], wherein the inner layer substrate is an insulating substrate;

[0027] [6] The wiring substrate according to any one of [1] to [4], wherein the inner layer substrate is a circuit substrate;

[0028] [7] A manufacturing method of a wiring substrate having an inductor function, comprising the following steps (A) to (G):

[0029] (A) a step of preparing an inner layer substrate having a first main surface and a second main surface and formed with an opening through the first main surface and the second main surface;

[0030] (B) a step of filling a magnetic body paste inside the opening and thermally curing the magnetic body paste to provide a magnetic body layer;

[0031] (C) a step of forming a first via hole through the first main surface and the second main surface of the magnetic body layer;

[0032] (D) a step of providing an insulating body inside the first via hole;

[0033] (E) a step of forming a second via hole through the insulating body;

[0034] (F) a step of forming a via conductor inside the second via hole; and

[0035] (G) a step of forming a first conductor pattern and a second conductor pattern on the first main surface and the second main surface of the magnetic body layer, respectively, in such a manner that the first conductor pattern and the second conductor pattern are connected by the via conductor in a solenoid shape;

[0036] [8] The method according to [7], wherein the viscosity (25°C) of the magnetic body paste is 20 to 250 Pa s;

[0037] [9] The method according to [7] or [8], wherein after the step (D), further comprising at least one of the following steps (D-1) and (D-2):

[0038] (D-1) a step of providing an insulating layer so as to be joined to the first main surface of the inner layer substrate and the first main surface of the magnetic body layer; and

[0039] (D-2) a step of providing an insulating layer so as to be joined to the second main surface of the inner layer substrate and the second main surface of the magnetic body layer;

[0040]

[10] The method according to [9], wherein, in the process (E), a second via hole that penetrates the insulating layer and the insulator is formed.

[0041]

[11] The method according to [9] or

[10] , further comprising a process of providing a conductor layer on a surface of the insulating layer on at least one of the first main surface and the second main surface of the inner layer substrate.

[0042] Effects of the Invention

[0043] If the present application is adopted, a wiring substrate with a built-in inductor structure and a manufacturing method thereof can be provided, which has excellent planar direction insulation, and has a magnetic body not only inside but also outside the conductor coil, thus providing excellent inductive characteristics.

[0044] Brief Description of the Drawings

[0045] Figure 1 is a schematic plan view showing an inductor structure portion of the wiring substrate in one embodiment of the present application;

[0046] Figure 2 is a schematic view (1) for explaining the manufacturing method in one embodiment of the present application;

[0047] Figure 3 is a schematic view (2) for explaining the manufacturing method in one embodiment of the present application;

[0048] Figure 4 is a schematic view (3) for explaining the manufacturing method in one embodiment of the present application;

[0049] Figure 5 is a schematic view (4) for explaining the manufacturing method in one embodiment of the present application;

[0050] Figure 6 is a schematic view (5) for explaining the manufacturing method in one embodiment of the present application;

[0051] Figure 7 is a schematic view (6) for explaining the manufacturing method in one embodiment of the present application;

[0052] Figure 8 is a schematic view (7) for explaining the manufacturing method in one embodiment of the present application, Figure 8 is a schematic cross-sectional view of the wiring substrate 100 according to one embodiment of the present application;

[0053] Figure 9 is a schematic view (8) for explaining the manufacturing method in one embodiment of the present application;

[0054] Figure 10 is a schematic view (9) for explaining a manufacturing method of one embodiment of the present application;

[0055] Figure 11 is a schematic view (10) for explaining a manufacturing method of one embodiment of the present application;

[0056] Figure 12 is a schematic view (11) for explaining a manufacturing method of one embodiment of the present application, Figure 12 is a schematic cross-sectional view of the wiring substrate 200 described in one embodiment of the present application;

[0057] Figure 13 is a schematic view (12) for explaining a manufacturing method of one embodiment of the present application;

[0058] Figure 14 is a schematic view (13) for explaining a manufacturing method of one embodiment of the present application;

[0059] Figure 15 is a schematic view (14) for explaining a manufacturing method of one embodiment of the present application, Figure 15 is a schematic cross-sectional view of the wiring substrate 300 described in one embodiment of the present application;

[0060] Figure 16 is a schematic plan view of a sensor structure portion of a wiring substrate in one embodiment of the present application. DETAILED DESCRIPTION

[0061] Embodiments of the present application will be described below with reference to the accompanying drawings. Note that each of the drawings is a schematic view for illustrating the shape, size, and arrangement of a component, and the present application is not limited to the following description. Each component can be changed as appropriate without departing from the spirit of the present application. In the drawings used in the following description, the same components are denoted by the same reference numerals, and repeated description can not be given in some cases. Furthermore, the components described in the embodiments of the present application are not limited to those manufactured or used through the configurations illustrated in the drawings.

[0062] [Wiring Substrate with Sensor Function]

[0063] The wiring substrate of the present application has a sensor structure built in the inside, and has a sensor function.

[0064] The wiring substrate of the present application is characterized in that the inductor structure includes a via conductor provided inside a via of the insulator as a part of a solenoid-shaped conductor pattern (conductor coil). Further, in the wiring substrate of the present application, a magnetic body layer is provided around the insulator in the direction of the main surface of the substrate (i.e., the direction parallel to the main surface of the substrate), as a result of which a magnetic body exists also outside the conductor coil. In addition, in the wiring substrate of the present application, an inner layer substrate is provided in the direction of the main surface of the substrate so as to surround the magnetic body layer, as a result of which the magnetic body layer exists in a region that is cut (divided) in the direction of the main surface of the substrate. Note that, as viewed in the direction perpendicular to the main surface of the substrate, the conductor pattern that forms the conductor coil together with the via conductor is provided inside the region of the magnetic body layer, as a result of which, as viewed in the direction perpendicular to the main surface of the substrate, the conductor coil as a whole exists inside the region of the magnetic body layer. The region that is cut in the direction of the main surface of the substrate has the magnetic body layer, so the planar direction insulation of the wiring substrate of the present application is excellent. Further, as viewed in the direction perpendicular to the main surface of the substrate, the region inside the magnetic body layer has the conductor coil, so the wiring substrate of the present application has a magnetic body not only inside the conductor coil but also outside the conductor coil, and exhibits excellent inductive characteristics. Note that, in the present application, the "inside of the conductor coil" and the "outside of the conductor coil" with respect to the positional relationship between the solenoid-shaped conductor pattern (conductor coil) and the magnetic body mean the inside and the outside of the cylinder structure defined by the conductor coil.

[0065] The structural features of the wiring substrate of the present application will be described with reference to Figure 8 ( Figure 12 and Figure 15 ) and Figure 1 . Note that, it is to be noted that the detailed contents of the constituent elements shown in the respective drawings will be described later, and in this column, the structural features that should be paid attention to will be described. Figure 8 is a schematic cross-sectional view of the wiring substrate 100 described in one embodiment of the present application. Figure 8 The wiring substrate 100 shown in Figure 8 is characterized by including an inner layer substrate 20 formed with an opening, a magnetic body layer 22 that is a magnetic body layer provided inside the opening and formed with a first via, an insulator 24 that is an insulator provided inside the first via and formed with a second via, and a via conductor 26 provided inside the second via, and by including the via conductor 26 provided inside the second via of the insulator 24 as a part of a conductor coil. Further, in the wiring substrate 100, the magnetic body layer exists in a region that is cut in the direction of the main surface of the substrate (region A in Figure 12 , which is cut by a region B of the inner layer substrate). Figure 15The diagram shows schematic cross-sectional views of wiring substrates 200 and 300 according to other embodiments of the present invention, wherein insulating layers 34 are respectively provided in contact with the two main surfaces of the inner substrate 20. Figure 8 Similarly, the wiring substrate 100 shown includes through-hole conductors 36 and 46 disposed inside a second through-hole penetrating an insulator as part of a conductor coil, and the area truncated in the main surface direction of the substrate ( Figure 12 and 15 Region A in the middle (which is cut off by region B of the inner substrate) contains a magnetic layer;

[0066] also, Figure 1 This is a schematic top view showing the sensor structure 10 (i.e., the sensor structure 10 built into the wiring substrate) of a wiring substrate according to one embodiment of the present invention. Figure 1 The symbols A and B in the text correspond to Figure 8 ( Figure 12 and Figure 15 The regions A and B are shown in Figure 1. It should be noted that, in the context of... Figure 1 The cross-section when the wiring substrate is cut at the position indicated by the X1-X1 dotted line corresponds to Figure 8 ( Figure 12 and Figure 15 A schematic cross-sectional view of ( ). Figure 1 The sensor structure 10 shown has a first conductor pattern, a second conductor pattern, and a through-hole conductor inside region A of the magnetic layer. Figure 1 Not shown in the image. Figure 8 , 12 The first conductor pattern is a solenoid-shaped conductor pattern (conductor coil) formed by "26", "36" and "46" in 15; the first conductor pattern is a first conductor pattern formed by through-hole pad 28a and connection pattern 28b. Figure 8 , 12 And in 15, “28”, “38” and “48”), the second conductor pattern is formed by through-hole pad 29a ( Figure 1 (not shown in the image) and the second conductor pattern formed by connecting pattern 29b ( Figure 8 , 12 (And "29", "39", and "49" in 15). As previously mentioned, the through-hole conductor is disposed inside the second through-hole penetrating the insulator. Figure 1 It can be seen that in the sensor structure 10, a magnetic body exists not only inside the conductor coil but also outside the conductor coil. It should be noted that... Figure 1 The coil axis of the conductor coil shown is along Figure 1 Extending vertically, magnetic bodies exist in both the axial outer region and the lateral outer region of the cylindrical structure defined by the conductor coil.

[0067] In the present application, a novel method of forming a desired conductor coil by forming an opening (first opening) in an inner layer substrate, providing a magnetic body layer inside the first opening, forming a through-hole (second opening) in the magnetic body layer, providing an insulator inside the second opening, further forming a through-hole (third opening) in the insulator, and providing a through-hole conductor is implemented, thereby realizing a wiring substrate having the above-described structural features.

[0068] In one embodiment, the wiring substrate of the present application comprises:

[0069] an inner layer substrate having a first main surface and a second main surface, and formed with an opening through the first and second main surfaces;

[0070] a magnetic body layer provided inside the opening, and formed with a first through-hole through the first and second main surfaces thereof;

[0071] an insulator provided inside the first through-hole, and formed with a second through-hole through the insulator; and

[0072] a sensor formed of a first conductor pattern formed on the first main surface of the magnetic body layer, a second conductor pattern formed on the second main surface of the magnetic body layer, and a through-hole conductor provided inside the second through-hole and connecting the first and second conductor patterns.

[0073] Hereinafter, embodiments of the wiring substrate of the present application will be described with appropriate reference to the drawings represented by Figure 8 , Figure 12 and Figure 15 It should be noted that the detailed contents of each component constituting the wiring substrate can be more clearly understood by incorporating the description of the "manufacturing method of a wiring substrate having a sensor structure" described later.

[0074] In the following description, for the convenience of explanation, the first main surface of the inner layer substrate or the magnetic body layer refers to the upper side main surface of the illustrated inner layer substrate or magnetic body layer, and the second main surface of the inner layer substrate or the magnetic body layer refers to the lower side main surface of the illustrated inner layer substrate or magnetic body layer. In addition, the first (second) main surface of the magnetic body layer refers to the main surface within the region A) in the magnetic body layer, and the first (second) main surface of the inner layer substrate refers to the main surface within the region B) in the inner layer substrate. Figure 1 , Figure 8 Figure 1 , Figure 8

[0075] Inner Layer Substrate

[0076] ​​In the wiring substrate of the present application, as the inner layer substrate, a publicly known inner layer substrate that can be used when the wiring substrate is manufactured can be used, and can be an insulating substrate or a circuit substrate.

[0077] The insulating substrate refers to a plate-like substrate having a first main surface and a second main surface facing each other, and exhibiting electrical insulation. As the insulating substrate, for example, a glass epoxy substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, a glass substrate, a ceramic substrate, and the like can be exemplified. In addition, as the insulating substrate, a cured prepreg can be used. The cured prepreg refers to a cured product of a prepreg. The prepreg is a sheet-like material containing a thermosetting resin composition and a sheet-like fibrous base material, and can be formed, for example, by impregnating the thermosetting resin composition into the sheet-like fibrous base material.

[0078] The circuit substrate refers to a plate-like substrate having a first main surface and a second main surface facing each other, one or both of which have circuit patterns (interlayer patterns such as via patterns, through-hole patterns, and surface patterns, which are not shown in the drawings of the present specification) formed thereon. An inner layer circuit substrate, which is an intermediate product in which an insulating layer and / or a conductor layer are further formed when the wiring substrate is manufactured, is also included in the "circuit substrate" in the present application. The substrate (base substrate) for the circuit substrate can be the insulating substrate described above.

[0079] The thickness of the inner layer substrate is not particularly limited and can be determined depending on the specific design of the manufactured wiring substrate. For example, from the viewpoint of thinning of the wiring substrate, the thickness of the inner layer substrate is preferably 2 mm or less, more preferably 1.5 mm or less, and even more preferably 1.2 mm or less, 1.0 mm or less, or 0.8 mm or less. The lower limit of the thickness of the inner layer substrate is not particularly limited and is preferably 50 μm or more, more preferably 60 μm or more, 80 μm or more, or 100 μm or more. In the case where the circuit substrate is used as the inner layer substrate, the thickness of the base substrate of the circuit substrate is preferably within the above range.

[0080] In the case where the circuit substrate is used as the inner layer substrate, the size of the circuit pattern provided in the inner layer substrate can be determined depending on the specific design of the manufactured wiring substrate. For example, from the viewpoint of thinning of the wiring substrate, the thickness of the surface pattern is preferably 40 μm or less, more preferably 35 μm or less, 30 μm or less, or 25 μm or less. The lower limit of the thickness of the surface pattern is not particularly limited and is usually 1 μm or more, 3 μm or more, 5 μm or more, or the like.

[0081] The inner layer substrate has an opening (first opening) (a through-hole) penetrating the first main surface and the second main surface thereof Figure 8 Figure 12 and Figure 15 ​In the present embodiment, the region A corresponds to the opening of the inner layer substrate 20). The shape of the opening is not particularly limited, and any shape such as a rectangular shape, a circular shape, an approximately rectangular shape, an approximately circular shape, or the like can be adopted. Further, the size of the opening varies depending on the design of the inductor structure portion, and for example, in the case where the shape of the opening is a rectangular shape, it is preferable that the size be 5 mm or less on each side, more preferably 3 mm or less on each side or 2 mm or less on each side. Further, in the case where the shape of the opening is a circular shape, it is preferable that the diameter be 5 mm or less, more preferably 3 mm or less or 2 mm or less. The lower limit of the size of the opening also varies depending on the size of the inductor structure to be incorporated therein, and in the case of a rectangular opening, it can generally be 0.5 mm or more on each side, and in the case of a circular opening, it can generally be 0.5 mm or more in diameter. In the case where a circuit substrate is used as the inner layer substrate, the opening is formed in a region of the circuit substrate in which no circuit wiring is formed.

[0082] Figure 8 Figure 12 Figure 15 The inner layer substrate 20 having only one opening is shown in FIGS. 1 to 3, but a plurality of openings can be formed at a prescribed interval from each other. In the case where the inner layer substrate has a plurality of openings, the shapes and sizes thereof can be the same or different.

[0083] Magnetic layer

[0084] The wiring substrate of the present embodiment is provided with a magnetic layer 22 disposed inside the opening of the inner layer substrate 20.

[0085] The magnetic layer 22 is disposed inside the opening of the inner layer substrate 20 in such a manner that the first main surface and the second main surface thereof in the direction perpendicular to the main surface of the substrate (the thickness direction of the substrate) substantially correspond to the first main surface and the second main surface of the inner layer substrate 20, respectively. That is, the magnetic layer is not protruded from or recessed from the inner layer substrate, and is disposed at substantially the same thickness as the inner layer substrate. Further, the magnetic layer 22 is disposed in engagement with the inner layer substrate 20 inside the opening of the inner layer substrate 20.

[0086] The magnetic layer 22 is a layer formed of a magnetic body, and the composition thereof is not particularly limited. For example, the magnetic layer can be a cured product layer obtained by curing a magnetic body composition (also referred to as "magnetic body paste") containing a magnetic powder and a binder resin. Details of the magnetic body paste will be described later in the section "Method for manufacturing wiring substrate having inductor function".

[0087] The magnetic layer 22 is provided with a first through-hole that penetrates the first main surface and the second main surface thereof. With respect to the first through-hole, it is also referred to as a "second opening" in relation to the opening (first opening) of the inner layer substrate 20.

[0088] In order to realize a desired conductor coil, a plurality of first through-holes can be formed in the magnetic layer 22. For example, in the case where the number of turns N of the conductor coil is 1, as shown in FIG. 4, a first through-hole 22a is formed in the magnetic layer 22.​​Figure 1 As shown, four through holes are sufficient. When the number of turns N is 2, as follows: Figure 16 As shown, six through holes are sufficient. The number of through holes in the first hole can be appropriately determined based on the design requirements of the conductor coil. It should be noted that... Figure 8 , Figure 12 and Figure 15 The schematic cross-sectional view shown is consistent with the view in the figure. Figure 1 The cross-section of the wiring board when it is cut at the position indicated by the X1-X1 dotted line corresponds to the first through hole, which is shown in only 2.

[0089] The shape of the first through hole is not particularly limited and can be any shape such as rectangular, circular, approximately rectangular, or approximately circular. Furthermore, the size of the first through hole (second opening) and the spacing between the first through holes are not particularly limited, as long as the desired conductor coil design can be achieved in relation to the size of the first opening.

[0090] From the viewpoint of achieving a wiring substrate with superior inductive characteristics, considering the cylindrical structure defined by the solenoid conductor pattern (conductor coil), it is preferable to determine the position of the first through-hole in such a way that sufficient magnetism exists both in its axial outer region and in its lateral outer region. For example, when the diameter of the first through-hole is set to D1, in the axial direction of the conductor coil ( Figure 1 , Figure 16 (The image shows the top and bottom directions in the attached diagram). The distance between the center of the first through-hole and the inner substrate is preferably 0.7D1 or more, more preferably 0.8D1 or more, 0.9D1 or more, or D1 or more. Furthermore, in the direction of the conductor coil's cylindrical side (perpendicular to the cylinder axis of the conductor coil), Figure 1 , Figure 16 (The center of the figure is in the left-right direction). The distance between the center of the first through hole and the inner substrate is preferably 0.7D1 or more, and more preferably 0.8D1 or more, 0.9D1 or more, or D1 or more.

[0091] -Insulator-

[0092] The wiring substrate of the present invention includes an insulator 24 disposed inside a first through hole in the magnetic layer 22.

[0093] The insulator 24 is preferably disposed within the first through-hole of the magnetic layer 22 such that its first and second main surfaces substantially correspond to the first and second main surfaces of the magnetic layer 22 (and the inner substrate 20), respectively, in a direction perpendicular to the main surface of the substrate (thickness direction of the substrate). That is, the insulator is preferably disposed without protruding or recessing from the magnetic layer, and is disposed with substantially the same thickness as the magnetic layer. Furthermore, the insulator 24 is disposed in contact with the magnetic layer 22 within the first through-hole of the magnetic layer. It should be noted that the embodiment in which the insulating layer 34 is disposed in contact with the two main surfaces of the inner substrate 20...Figure 12 and Figure 15 In the wiring substrate of

[0094] The insulator 24 is not particularly limited in composition as long as it exhibits electrical insulation. For example, the insulator can be a cured product layer obtained by curing a resin composition (also referred to as "insulating via-filling paste") containing an insulating resin. Details of the insulating via-filling paste are described later in the section "Method for manufacturing a wiring substrate having an inductor function".

[0095] The second via is formed in the insulator 24 provided in the first via of the magnetic layer 22. Therefore, the number of the second via is usually the same as the number of the first via. For example, in the case where the number of turns N of the conductor coil is 1, as shown in Figure 1 , four first vias are formed, and the insulator is provided in each of the first vias and the second via is formed. In the case where the number of turns N of the conductor coil is 2, as shown in Figure 16 , six first vias are formed, and the insulator is provided in each of the first vias and the second via is formed. Note that, as shown in Figure 8 , Figure 12 and Figure 15 , the schematic cross-sectional views correspond to the cross sections when the wiring substrate is cut at the position indicated by the broken line X1-X1, and only two second vias are shown. Figure 1

[0096] The shape of the second via is not particularly limited, and any shape such as a rectangular shape, a circular shape, an approximately rectangular shape, and an approximately circular shape can be adopted. Further, the size of the second via and the interval between the second vias are not particularly limited as long as a desired design of the conductor coil can be achieved in relation to the size of the first opening. For example, when the diameter of the first via is D1, the diameter D2 of the second via is preferably 0.8D1 or less, more preferably 0.7D1 or less, 0.6D1 or less, or 0.5D1 or less, and preferably 0.2D1 or more, more preferably 0.3D1 or more. If the diameter D2 of the second via is within the range, the insulator around the via conductor has a sufficient thickness, and a wiring substrate having more excellent inductive characteristics can be achieved. Further, the interval between the second vias is preferably determined so as to be substantially the same as the interval between the first vias.

[0097] In the present application, the solenoid-shaped conductor pattern (conductor coil) is formed by forming the first via in the magnetic layer, providing the insulator inside the first via, and further forming the second via in the insulator and providing the via conductor, thereby achieving the wiring substrate having the above-described structural features. ​

[0098] Inductor

[0099] The wiring substrate of the present application has an inductor formed of "a first conductor pattern 28, 38, 48 formed on a first main surface of a magnetic layer 22", "a second conductor pattern 29, 39, 49 formed on a second main surface of the magnetic layer 22", and "a via conductor 26, 36, 46 provided inside a second via and connecting the first conductor pattern and the second conductor pattern".

[0100] In the present application, the matter that the first conductor pattern is "formed on a first main surface of a magnetic layer" includes a case where the first conductor pattern is provided on the first main surface of the magnetic layer in bonding (directly), and also includes a case where the first conductor pattern is provided on the first main surface of the magnetic layer via another layer. The same applies to the matter that the second conductor pattern is "formed on a second main surface of a magnetic layer", and includes a case where the second conductor pattern is provided on the second main surface of the magnetic layer in bonding (directly), and also includes a case where the second conductor pattern is provided on the second main surface of the magnetic layer via another layer. Here, as the other layer, there is no particular limitation as long as the effect of the present application is not hindered, and an insulating layer can be cited as an example. Therefore, in one embodiment, the wiring substrate of the present application further includes an insulating layer 34 provided in bonding with the first main surface of the inner layer substrate 20 and the first main surface of the magnetic layer 22, and the first conductor pattern 38, 48 is provided on the first main surface of the magnetic layer 22 in bonding with the surface of the insulating layer 34. Further, in another embodiment, the wiring substrate of the present application further includes an insulating layer 34 provided in bonding with the second main surface of the inner layer substrate 20 and the second main surface of the magnetic layer 22, and the second conductor pattern 39, 49 is provided on the second main surface of the magnetic layer 22 in bonding with the surface of the insulating layer 34.

[0101] Figure 8 In the wiring substrate 100 shown, the first conductor pattern 28 and the second conductor pattern 29 are provided in bonding with the first main surface and the second main surface of the magnetic layer 22, respectively. On the other hand, Figure 12 and Figure 15 In the wiring substrates 200, 300 shown, the first conductor pattern 38, 48 is provided on the first main surface of the magnetic layer 22 in bonding with the surface of the insulating layer 34, and the second conductor pattern 39, 49 is provided on the second main surface of the magnetic layer 22 in bonding with the surface of the insulating layer 34.

[0102] The first conductor pattern and the second conductor pattern are connected by the via conductor provided inside the second via of the insulating layer, and form a solenoid-shaped conductor pattern (conductor coil). Thereby, an inductor function is exerted.

[0103] The structure of the first conductor pattern is not limited as long as it can form a conductor coil together with the through-hole conductor and the second conductor pattern. For example, the first conductor pattern can be formed by through-hole pad 28a and a connecting pattern 28b that connects the through-hole pads to each other. Figure 1 The second conductor pattern is similar, for example, it can be formed by through-hole pads 29a and connection patterns 29b that connect the through-hole pads to each other. Figure 1 (Through-hole pad 29a not shown).

[0104] The structure of a through-hole conductor is not limited as long as it can form a conductor coil together with the first conductor pattern and the second conductor pattern. For example, a through-hole conductor can be a hollow cylindrical conductor formed by plating the through-hole wall (conformal through-hole conductor), or it can be a cylindrical conductor formed by filling the through-hole with a conductor (filled through-hole conductor). In the case of a conformal through-hole conductor, the interior of the hollow cylindrical conductor can be filled with insulators 27, 37, and 47.

[0105] -Other Structures-

[0106] For the wiring substrate of the present invention, in the case where an insulating layer 34 is provided in contact with at least one of the main surfaces of the first main surface and the second main surface of the inner layer substrate 20 ( Figure 12 and Figure 15 It may also include a conductor layer (wiring layer, not shown) disposed in contact with the surface of the insulating layer.

[0107] For the wiring substrate of the present invention, an insulating layer and a conductor layer (wiring layer) may be alternately disposed on at least one of the main surfaces of the first main surface and the second main surface of the inner layer substrate 20 (and the magnetic layer 22) to form a multilayer wiring. Regarding the specific design of the insulating layer and the wiring layer, and the multilayer wiring, layer configurations and designs known in the manufacture of wiring substrates can be adopted. For example, by using… Figure 8 , Figure 12 and Figure 15 The wiring substrate shown serves as an inner circuit substrate, on which insulating layers and conductor layers are alternately disposed, thereby enabling the fabrication of a wiring substrate with multi-layer wiring that incorporates a sensor structure.

[0108] The wiring substrate of the present invention can be used to manufacture semiconductor devices of various forms. Semiconductor devices comprising the wiring substrate are well suited for use in electrical products (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., two-wheeled motor vehicles, automobiles, trams, ships, and aircraft).

[0109] [Manufacturing method of wiring board with sensor function]

[0110] The present invention also provides a novel method for manufacturing a wiring substrate with sensor functionality.

[0111] The method of the present application includes:

[0112] a step of preparing an inner layer substrate having an opening formed therein;

[0113] a step of providing a magnetic body layer inside the opening;

[0114] a step of providing a first via hole in the magnetic body layer;

[0115] a step of providing an insulating body inside the first via hole;

[0116] a step of providing a second via hole in the insulating body; and

[0117] a step of providing a conductor pattern on both main surfaces of the magnetic body layer and a via conductor inside the second via hole so that they are connected to form a solenoid-shaped conductor pattern. Thus, the wiring substrate having the above-described structural features, in which the region cut off in the direction of the main surface of the substrate has the magnetic body layer and has the solenoid-shaped conductor pattern (conductor coil) inside the region of the magnetic body layer as viewed in the direction perpendicular to the main surface of the substrate, can be realized.

[0118] Hereinafter, the manufacturing method of the wiring substrate according to the present application will be described in detail with reference to the drawings. Figure 8 , Figure 12 and Figure 15 illustrated in the drawings.

[0119] In one embodiment, the manufacturing method of the wiring substrate having an inductor function according to the present application includes the following steps (A) to (G):

[0120] (A) a step of preparing an inner layer substrate having a first main surface and a second main surface and having an opening formed therethrough between the first main surface and the second main surface;

[0121] (B) a step of filling a magnetic body paste inside the opening and thermally curing the magnetic body paste to provide a magnetic body layer;

[0122] (C) a step of forming a first via hole through the magnetic body layer between the first main surface and the second main surface;

[0123] (D) a step of providing an insulating body inside the first via hole;

[0124] (E) a step of forming a second via hole through the insulating body;

[0125] (F) a step of forming a via conductor inside the second via hole; and

[0126] (G) A process of forming a first conductor pattern and a second conductor pattern on a first main surface and a second main surface of a magnetic body layer, respectively, such that the first conductor pattern and the second conductor pattern are connected in a solenoid manner through a through-hole conductor.

[0127] - Process (A) -

[0128] In process (A), an inner layer substrate having a first main surface and a second main surface and having an opening through the first main surface and the second main surface is prepared.

[0129] The first step is to prepare the inner layer substrate ( Figure 2 The inner layer substrate 20 has a first main surface 20a and a second main surface 20b. The inner layer substrate 20 can be any known inner layer substrate that can be used in the manufacture of a wiring substrate; it can be an insulating substrate or a circuit substrate. Details of the inner layer substrate 20 are as described above. It should be noted that, in the case where the inner layer substrate 20 is a circuit substrate, although not shown in the figure, it has patterned circuit wiring (such as via wiring, through-hole wiring, interlayer wiring, and surface wiring) on ​​one or both sides of its first and second main surfaces.

[0130] The second step is to form an opening on the inner substrate that extends between its first main surface and its second main surface. Figure 3 ).like Figure 3 Schematic illustration shows that an opening 21 penetrating between the first and second main surfaces of the inner layer substrate 20 can be formed at a predetermined location on the inner layer substrate 20. When the inner layer substrate 20 is a circuit substrate, the opening 21 can be formed in a region of the base substrate where no circuit wiring exists. Regarding the opening 21, it can be formed using known methods such as drill bits, lasers, plasma, etching media, etc., taking into account the characteristics of the inner layer substrate 20 and the size of the opening 21. It should be noted that the shape and size of the opening 21 are as described above.

[0131] Figure 3 Only one opening 21 is shown, but multiple openings 21 can be arranged at predetermined intervals. By providing multiple openings 21, multiple sensor structures can be built into the wiring substrate.

[0132] - Process (B) -

[0133] In step (B), a magnetic slurry is filled into the opening and the magnetic slurry is thermo-cured to form a magnetic layer.

[0134] The magnetic slurry comprises (a) magnetic powder and (b) binder resin, and may further comprise (c) dispersant, (d) curing accelerator and (e) other additives as needed.

[0135] (a) Magnetic powder

[0136] As the magnetic powder, for example, pure iron powder, Mg-Zn-based ferrite, Fe-Mn-based ferrite, Mn-Zn-based ferrite, Mn-Mg-based ferrite, Cu-Zn-based ferrite, Mg-Mn-Sr-based ferrite, Ni-Zn-based ferrite, Ba-Zn-based ferrite, Ba-Mg-based ferrite, Ba-Ni-based ferrite, Ba-Co-based ferrite, Ba-Ni-Co-based ferrite, Y-based ferrite, iron oxide powder (III), ferric oxide powder, Fe-Si-based alloy powder, Fe-Si-Al-based alloy powder, Fe-Cr-based alloy powder, Fe-Cr-Si-based alloy powder, Fe-Ni-Cr-based alloy powder, Fe-Cr-Al-based alloy powder, Fe-Ni-based alloy powder, Fe-Ni-Mo-based alloy powder, Fe-Ni-Mo-Cu-based alloy powder, Fe-Co-based alloy powder, Fe-Ni-Co-based alloy powder, and amorphous alloy-based powder such as Co-based amorphous alloy can be listed.

[0137] Among them, as the magnetic powder, at least one selected from the group consisting of iron oxide powder and ferrous alloy-based metal powder is preferable. As the iron oxide powder, ferrite containing at least one selected from the group consisting of Ni, Cu, Mn and Zn is preferable. In addition, as the ferrous alloy-based metal powder, ferrous alloy-based metal powder containing at least one selected from the group consisting of Si, Cr, Al, Ni and Co is preferable.

[0138] As the magnetic powder, commercially available magnetic powders can be used. As specific examples of the commercially available magnetic powders, "M05S" manufactured by Powdertech Co., Ltd., "PST-S" manufactured by San'yosho Co., Ltd., "AW2-08", "AW2-08PF20F", "AW2-08PF10F", "AW2-08PF3F", "Fe-3.5Si-4.5CrPF20F", "Fe-50NiPF20F", "Fe-80Ni-4MoPF20F" manufactured by EPSON ATMIX Co., Ltd., "LD-M", "LD-MH", "KNI-106", "KNI-106GSM", "KNI-106GS", "KNI-109", "KNI-109GSM", "KNI-109GS" manufactured by JFE Chemicals Co., Ltd., "KNS-415", "BSF-547", "BSF-029", "BSN-125", "BSN-125", "BSN-714", "BSN-828", "S-1281", "S-1641", "S-1651", "S-1470", "S-1511", "S-2430" manufactured by Todo Sangyo Co., Ltd., "JR09P2" manufactured by Nippon Rika Kogyo Co., Ltd., "Nanotek" manufactured by CIK NanoTek Corporation, "JEMK-S", "JEMK-H" manufactured by KINSEI MATEC Co., Ltd., "Yttrium iron oxide" manufactured by ALDRICH Co., and the like can be listed. The magnetic powder can be used singly in one kind, or two or more kinds can be used in combination.

[0139] The magnetic powder is preferably spherical. The value obtained by dividing the length of the long axis of the magnetic powder by the length of the short axis (aspect ratio) is preferably 2 or less, more preferably 1.5 or less, and further more preferably 1.2 or less. In general, when the magnetic powder is in a flat shape other than a spherical shape, it is easier to increase the relative magnetic permeability. However, in particular when the spherical magnetic powder is used, it is generally possible to reduce the magnetic loss and to obtain a slurry having a preferable viscosity, and this is preferable from this viewpoint.

[0140] From the viewpoint of increasing the relative magnetic permeability, the average particle diameter of the magnetic powder is preferably 0.01 μm or more, more preferably 0.5 μm or more, and further more preferably 1 μm or more. In addition, it is preferably 10 μm or less, more preferably 9 μm or less, and further more preferably 8 μm or less.

[0141] The average particle diameter of the magnetic powder can be measured by a laser diffraction scattering method based on Mie scattering theory. Specifically, the particle diameter distribution of the magnetic powder can be measured by a laser diffraction scattering particle diameter distribution measuring device on a volume basis, and the median particle diameter thereof can be measured as the average particle diameter. The measurement sample can preferably be a sample obtained by dispersing the magnetic powder in water by ultrasonic waves. As the laser diffraction scattering particle diameter distribution measuring device, "LA-500" manufactured by HORIBA, Ltd., "SALD-2200" manufactured by Shimadzu Corporation, or the like can be used.

[0142] From the viewpoint of increasing the relative magnetic permeability, the specific surface area of the magnetic powder is preferably 0.05 m 2 / g or more, more preferably 0.1 m 2 / g or more, further more preferably 0.3 m 2 / g or more. Furthermore, it is preferably 10 m 2 / g or less, more preferably 8 m 2 / g or less, further more preferably 5 m 2 / g or less. The specific surface area of the magnetic powder can be measured by the BET method.

[0143] From the viewpoints of increasing the relative magnetic permeability and reducing the loss coefficient, the content (volume %) of the magnetic powder is preferably 40 volume % or more, more preferably 50 volume % or more, further more preferably 60 volume % or more, in the case where the non-volatile components in the magnetic material paste are assumed to be 100 volume %. The upper limit of the content (volume %) is not particularly limited, and can be assumed to be 95 volume % or less, 90 volume % or less, or the like, for example.

[0144] From the viewpoints of increasing the relative magnetic permeability and reducing the loss coefficient, the content (mass %) of the magnetic powder is preferably 70 mass % or more, more preferably 75 mass % or more, further more preferably 80 mass % or more, when the non-volatile components in the resin composition are assumed to be 100 mass %. The upper limit of the content (mass %) is not particularly limited, and can be assumed to be 99 mass % or less, 98 mass % or less, or the like, for example.

[0145] (b) a binder resin

[0146] The binder resin is not particularly limited as long as it is a resin that can disperse and bind the magnetic powder in the magnetic material paste to form a magnetic material layer.

[0147] As the binder resin, for example, thermosetting resins such as epoxy resins, phenol-based resins, naphthol-based resins, benzoxazine-based resins, active ester-based resins, cyanate ester-based resins, carbodiimide-based resins, amine-based resins, acid anhydride-based resins, and thermoplastic resins such as phenoxy resins, acrylic resins, polyvinyl acetal resins, butyral resins, polyimide resins, polyamide-imide resins, polyether sulfone resins, and polysulfone resins can be exemplified. As the binder resin, it is preferable to use a thermosetting resin used when forming the insulating layer of the wiring substrate, and it is more preferable to use an epoxy resin. The binder resin can be used singly or in combination of two or more. Here, components such as phenol-based resins, naphthol-based resins, benzoxazine-based resins, active ester-based resins, cyanate ester-based resins, carbodiimide-based resins, amine-based resins, and acid anhydride-based resins, which react with the epoxy resin to cure the magnetic material slurry, are collectively referred to as "curing agent".

[0148] The epoxy equivalent of the epoxy resin is preferably 50 g / eq. to 5000 g / eq., more preferably 50 g / eq. to 3000 g / eq., further more preferably 80 g / eq. to 2000 g / eq., and still further more preferably 110 g / eq. to 1000 g / eq. By being within this range, the crosslinking density of the cured product becomes sufficient, and a magnetic material layer having a small surface roughness can be obtained. Note that the epoxy equivalent can be measured in accordance with JIS K7236, and is the mass of a resin containing one equivalent of an epoxy group.

[0149] The weight average molecular weight of the epoxy resin is preferably 100 to 5000, more preferably 250 to 3000, and further more preferably 400 to 1500. Here, the weight average molecular weight of the epoxy resin is the polystyrene conversion weight average molecular weight measured by gel permeation chromatography (GPC).

[0150] In the case where the epoxy resin and the curing agent are contained as the binder resin, the ratio of the amount of the epoxy resin to the amount of all the curing agents is preferably in the range of 1:0.01 to 1:5, more preferably in the range of 1:0.5 to 1:3, and further more preferably in the range of 1:1 to 1:2, in terms of the ratio of [the total number of epoxy groups of the epoxy resin]:[the total number of reactive groups of the curing agent]. Here, the "number of epoxy groups of the epoxy resin" is the value obtained by totaling the values obtained by dividing the mass of the nonvolatile component of the epoxy resin present in the magnetic material slurry by the epoxy equivalent. In addition, the "number of active groups (reactive groups) of the curing agent" is the value obtained by totaling the values obtained by dividing the mass of the nonvolatile component of the curing agent present in the magnetic material slurry by the active group equivalent.

[0151] From the viewpoint of allowing the magnetic powder to be dispersed and incorporated in the magnetic material paste to form the magnetic material layer, the content of the binder resin is preferably 1% by mass or more, 3% by mass or more, or 5% by mass or more, based on 100% by mass of the nonvolatile components in the magnetic material paste. The upper limit is not particularly limited as long as the effects of the present application are exerted, and is preferably 25% by mass or less, 20% by mass or less, or 15% by mass or less.

[0152] (c) dispersant

[0153] The magnetic material paste can further include a dispersant. By using the dispersant, the dispersibility of the magnetic powder can be improved.

[0154] As the dispersant, for example, phosphate ester-based dispersants such as polyoxyethylene alkyl ether phosphoric acid, anionic dispersants such as sodium dodecylbenzenesulfonate, sodium laurate, and ammonium salts of polyoxyethylene alkyl ether sulfate, organosiloxane-based dispersants, nonionic dispersants such as acethylene glycol, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitol fatty acid ester, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine, and polyoxyethylene alkyl amide, and the like can be exemplified. Among them, the anionic dispersant is preferable. One kind of dispersant can be used alone, or two or more kinds of dispersants can be used in combination.

[0155] The content of the dispersant is preferably 0.1% by mass or more, 0.2% by mass or more, or 0.4% by mass or more, and the upper limit is preferably 5% by mass or less, 3% by mass or less, or 1% by mass or less, based on 100% by mass of the nonvolatile components in the magnetic material paste.

[0156] (d) curing accelerator

[0157] The magnetic material paste can further include a curing accelerator. By using the curing accelerator, the curing of the binder resin can be effectively performed, and the mechanical strength of the cured product can be improved. As the curing accelerator, for example, amine-based curing accelerators, imidazole-based curing accelerators, phosphorus-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, and the like can be exemplified. From the viewpoint of obtaining a magnetic material paste exhibiting an appropriate viscosity, the curing accelerator is preferably an amine-based curing accelerator, an imidazole-based curing accelerator, and more preferably an imidazole-based curing accelerator. One kind of curing accelerator can be used alone, or two or more kinds of curing accelerators can be used in combination.

[0158] From the viewpoint of obtaining a magnetic material paste exhibiting an appropriate viscosity, the content of the curing accelerator is preferably 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more, based on 100% by mass of the nonvolatile components in the magnetic material paste. The upper limit is preferably 3% by mass or less, 2% by mass or less, or 1% by mass or less.

[0159] (e) other additives

[0160] The magnetic material slurry can further contain other additives as needed. As the other additives, resin additives such as a curing retardant such as triethyl borate, a flame retardant, a thickening agent, a defoaming agent, an inorganic filler (excluding the magnetic powder), a leveling agent, an adhesion imparting agent, and a coloring agent, and the like can be exemplified.

[0161] From the viewpoint of being able to sufficiently fill the openings of the inner layer substrate (and being able to form the desired magnetic material layer), the viscosity (25°C) of the magnetic material slurry is preferably 20 Pa s or more, more preferably 30 Pa s or more, and even more preferably 40 Pa s or more, and is typically 250 Pa s or less, preferably 220 Pa s or less, and more preferably 200 Pa s or less. With respect to the viscosity, the temperature of the magnetic material slurry can be maintained at 25 ± 2°C and measured using an E-type viscometer.

[0162] With respect to the filling of the magnetic material slurry into the openings of the inner layer substrate, methods such as a method in which the magnetic material slurry is filled into the openings using a squeegee, a method in which the magnetic material slurry is filled into the openings using a cartridge, a method in which a mask printing is performed to fill the magnetic material slurry, a roll coating method, an inkjet method, and the like can be exemplified. From the viewpoint of being able to fill without voids, the filling of the magnetic material slurry is preferably performed under reduced pressure or under vacuum.

[0163] After the magnetic material slurry is filled into the openings of the inner layer substrate, the magnetic material slurry is heat-cured to form a magnetic material layer. The heat-curing conditions of the magnetic material slurry differ depending on the composition and type of the magnetic material slurry, and the curing temperature is preferably 120°C or more, more preferably 130°C or more or 140°C or more, and is preferably 240°C or less, more preferably 220°C or less or 200°C or less. The curing time is preferably 5 minutes or more, more preferably 10 minutes or more or 15 minutes or more, and is preferably 120 minutes or less, more preferably 100 minutes or less or 90 minutes or less.

[0164] Prior to heat-curing the magnetic material slurry, a pre-heating treatment in which the magnetic material slurry is heated at a temperature lower than the curing temperature can be performed. For example, the magnetic material slurry can be pre-heated at a temperature of typically 50°C or more and less than 150°C (preferably 60°C or more and 140°C or less, and more preferably 70°C or more and 130°C or less) for typically 5 minutes or more (preferably 5 minutes to 150 minutes, and more preferably 15 minutes to 120 minutes) prior to heat-curing the magnetic material slurry.

[0165] Accordingly, a magnetic material layer 22 is formed in the openings 21 of the inner layer substrate 20 Figure 4 It should be noted that the magnetic material layer 22 is preferably formed so as to protrude from the inner layer substrate 20, and then the excess magnetic material layer 22 that protrudes or adheres from the inner layer substrate 20 is removed by polishing, and is planarized and smoothed. Accordingly, as shown in FIG. 2B, the magnetic material layer 22 is formed in the openings 21 of the inner layer substrate 20. Figure 4Schematic illustration shows that a magnetic layer 22 can be formed inside the opening 21 of the inner layer substrate 20 such that its first and second main surfaces substantially correspond to the first and second main surfaces of the inner layer substrate 20 in a direction perpendicular to the main surface of the substrate (thickness direction of the substrate). Examples of such polishing methods include polishing, belt polishing, and roller polishing. Commercially available polishing apparatuses include the NT-700IM polishing apparatus and the #1500 ceramic roller polishing apparatus manufactured by Ishii Optoelectronics Co., Ltd.

[0166] - Process (C) -

[0167] In process (C), a first through hole is formed between the first main surface and the second main surface of the magnetic body layer.

[0168] To form the desired conductor coil, a plurality of first through-holes 23 are formed in the magnetic layer 22. For example, when the number of turns N of the conductor coil is 1, such as Figure 1 As shown, four through holes are sufficient. When the number of turns N is 2, as follows: Figure 16 As shown, six through holes are sufficient. The number of through holes in the first stage can be appropriately determined based on the desired design of the conductor coil. It should be noted that... Figure 5 The schematic cross-sectional view shown is in the figure. Figure 1 The cross-section of the wiring board when it is cut at the position indicated by the X1-X1 dotted line corresponds to the first through hole 23, which is shown in only 2.

[0169] Regarding the first via 23, it can be formed using known methods such as drill bits, lasers, plasma, etching media, etc., taking into account the characteristics of the magnetic layer 22 and the size of the first via 23. It should be noted that, regarding the shape of the first via 23, as mentioned above, the size of the first via and the spacing between the first vias are not particularly limited, as long as the desired conductor coil design can be achieved in relation to the size of the opening 21 of the inner substrate 20 (which corresponds to the size of the magnetic layer 22).

[0170] From the viewpoint of achieving a wiring substrate with superior inductive characteristics, considering the cylindrical structure defined by the solenoid conductor pattern (conductor coil) formed in the later process (G), it is preferable to determine the position of the first through-hole in such a way that sufficient magnetism exists in both its axial outer region and its lateral outer region. For example, when the diameter of the first through-hole is set to D1, in the cylindrical axial direction of the conductor coil ( Figure 1 , Figure 16 (The image shows the top and bottom directions in the attached diagram). The distance between the center of the first through-hole and the inner substrate is preferably 0.7D1 or more, more preferably 0.8D1 or more, 0.9D1 or more, or D1 or more. Furthermore, in the direction of the conductor coil's cylindrical side (perpendicular to the cylinder axis of the conductor coil), Figure 1 ,Figure 16 The distance from the center position of the first through-hole to the inner layer substrate is preferably 0.7D1 or more, more preferably 0.8D1 or more, 0.9D1 or more, or D1 or more.

[0171] - Step (D) -

[0172] In Step (D), an insulator is provided inside the first through-hole.

[0173] Step (D) is not particularly limited as long as an insulator can be provided inside the first through-hole. For example, an insulating via-filling paste containing an insulating resin can be filled in the first through-hole, and the insulating via-filling paste can be thermally cured to provide the insulator.

[0174] The insulating via-filling paste is not particularly limited as long as it can be filled in the first through-hole and forms an insulator by thermal curing. For example, the insulating via-filling paste contains an insulating resin, and can further contain an inorganic filler (excluding magnetic powder), a curing accelerator, and other additives as needed.

[0175] As the insulating resin, the same adhesive resin described for the aforementioned magnetic material paste can be used, and the preferred type and properties are also the same. When the non-volatile content of the insulating via-filling paste is 100% by mass, the content of the insulating resin is preferably 1% by mass or more, 3% by mass or more, or 5% by mass or more. The upper limit of the content is not particularly limited, and is preferably 90% by mass or less, 80% by mass or less, or 70% by mass or less.

[0176] As the inorganic filler (excluding magnetic powder), for example, silica, alumina, glass, cordierite, silicon oxide, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium phosphotungstate, etc. can be listed. Among these, amorphous silica, fused silica, crystalline silica, synthetic silica, hollow silica, etc. are particularly preferred. In addition, as the silica, spherical silica is preferable. The inorganic filler can be used alone or in combination with two or more kinds.

[0177] From the viewpoint of achieving sufficient filling properties, the average particle diameter of the inorganic filler is preferably in the range of 0.01 μm to 4 μm, more preferably in the range of 0.05 μm to 2 μm, further more preferably in the range of 0.1 μm to 1 μm, and still further more preferably in the range of 0.3 μm to 0.8 μm. The average particle diameter of the inorganic filler can be measured in the same manner as described for the average particle diameter of the magnetic powder.

[0178] From the viewpoint of improving moisture resistance and dispersibility, the inorganic filler material is preferably treated with one or more surface treatment agents selected from the group consisting of amino silane-based coupling agents, epoxy silane-based coupling agents, mercapto silane-based coupling agents, alkoxy silane compounds, organosilazane compounds, titanate-based coupling agents, and the like.

[0179] When the non-volatile content of the insulation hole-filling paste is taken as 100 mass%, the content of the inorganic filler material is preferably 5 mass% or more, 10 mass% or more, or 20 mass% or more, and is preferably 95 mass% or less, 90 mass% or less, or 80 mass% or less.

[0180] As for the curing accelerator and other additives, the same substances as those described with respect to the magnetic body paste can be used.

[0181] The operation of filling the first through-holes with the insulation hole-filling paste and the thermal curing of the insulation hole-filling paste can be performed by the same method and conditions as those of step (B).

[0182] Thus, the insulator 24 is formed inside the first through-hole 23 of the magnetic body layer 22. Figure 6 It should be noted that, for the insulator 24, it is preferable to be formed in a manner protruding from the magnetic body layer 22, and then the excess insulator 24 protruding from or adhering to the magnetic body layer 22 is removed by polishing to perform planarization and smoothing. Thus, as Figure 6 schematically shown, it is possible to form the insulator 24 inside the first through-hole 23 of the magnetic body layer 22 in a manner that its first main surface and second main surface substantially correspond to the first main surface and second main surface of the magnetic body layer 22, respectively, in the direction perpendicular to the main surface of the substrate (the thickness direction of the substrate). As for the polishing, the same method as that described with respect to step (B) can be used.

[0183] - Step (E) -

[0184] In step (E), a second through-hole that penetrates the insulator is formed.

[0185] The second through-hole 25 is formed in the insulator 24 provided in the first through-hole 23 of the magnetic body layer 22 Figure 7 , also with reference to Figure 5 , Figure 6 . Thus, the number of second through-holes 25 can generally be the same as the number of first through-holes 23. For example, in the case where the number of turns N of the conductor coil is 1, as shown in Figure 1 , four first through-holes are provided, and the insulator is formed therein and the second through-hole is provided. In the case where the number of turns N is 2, as shown in Figure 16 , six first through-holes are provided, and the insulator is formed therein and the second through-hole is provided. It should be noted that, as shown in Figure 7 the schematic cross-sectional view shown in is a cross-sectional view taken along the line A-A in the schematic plan view shown in .Figure 1 The cross sections of the second via holes 25 correspond to the positions indicated by the dotted lines X1-X1 when the wiring substrate is cut.

[0186] The second via holes 25 can be formed by using a known method such as a drill, a laser, a plasma, an etching medium, and the like, taking into consideration the characteristics of the insulator 24 and the size of the second via holes 25. Note that the shape of the second via holes 25 is as described above, and the size of the second via holes and the interval between the second via holes are not particularly limited as long as a desired design of the conductor coil can be achieved in relation to the size of the first opening. For example, when the diameter of the first via hole is Dl, the diameter D2 of the second via hole is preferably 0.8Dl or less, more preferably 0.7Dl or less, 0.6Dl or less, or 0.5Dl or less, and is preferably 0.2Dl or more, more preferably 0.3Dl or more. If the diameter D2 of the second via hole is within the range, there is a sufficient thickness of the insulator between the magnetic layer and the via conductor, which contributes to further improvement of the inductance characteristics. Further, the interval between the second via holes is preferably determined so as to substantially match the interval between the first via holes.

[0187] - Step (F) -

[0188] In step (F), the via conductor is formed inside the second via hole.

[0189] Preferably, desmear treatment is performed on the inside of the second via hole and the surface of the substrate before the via conductor is formed. As the desmear treatment, a known desmear treatment that can be used when forming the interlayer conductor in the manufacture of the wiring substrate can be performed, and either dry or wet desmear treatment can be performed. As an example of the dry desmear treatment, plasma treatment and the like can be given. Further, as an example of the wet desmear treatment, a method in which swelling treatment using a swelling solution, roughening treatment using an oxidizing agent, and neutralization treatment using a neutralizing solution are sequentially performed can be given.

[0190] The via conductor can be formed by plating treatment on the second via hole. For example, the via conductor can be formed by forming a plating seed layer by non-electrolytic plating, and then forming a metal layer on the plating seed layer by electrolytic plating.

[0191] The via conductor is not particularly limited as long as it can form the conductor coil together with the first conductor pattern and the second conductor pattern described later. For example, the via conductor can be a hollow cylindrical conductor (conformal via conductor) formed by plating on the via hole wall, or can be a cylindrical conductor (filled via conductor) formed by filling the via hole with a conductor.

[0192] In the case of forming a conformal via conductor as the via conductor, the inside of the hollow cylindrical conductor can be filled with an insulator. The filling of the insulator is performed in the same manner as in the process (D), and for example, an insulating via-filling paste can be filled and thermally cured to form the insulator. Note that, in the case of the insulator, it is preferable to be formed so as to protrude from the second via, and then, the excess insulator protruding from or adhering to the second via is removed by polishing to perform planarization and smoothing. As for the polishing, it can be performed by the same method as the method described with respect to the process (B).

[0193] As the conductor material constituting the via conductor, for example, one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium can be listed. The via conductor can be composed of a single metal, or can be composed of an alloy, and as the alloy, for example, an alloy of two or more metals selected from the above metals, such as a nickel-chromium alloy, a copper-nickel alloy, and a copper-titanium alloy can be listed.

[0194] Process (G)

[0195] In the process (G), the first conductor pattern and the second conductor pattern are formed on the first main surface and the second main surface of the magnetic body layer, respectively, in such a manner that the first conductor pattern and the second conductor pattern are connected by the via conductor in a solenoid shape.

[0196] It is preferable to perform a desmear treatment on the surface of the substrate before forming the first conductor pattern and the second conductor pattern. As the desmear treatment, a publicly known desmear treatment that can be used when forming a circuit conductor in the manufacture of a wiring substrate can be performed, and either a dry method or a wet method can be used for the desmear treatment. Examples of the desmear treatment are described in the process (F).

[0197] The first conductor pattern and the second conductor pattern can be formed using a publicly known conductor pattern (circuit conductor) formation technique such as a subtractive method or a semi-additive method.

[0198] For example, in the subtractive method, the unnecessary portion (non-circuit formation portion) of the plated conductor layer is selectively removed by etching or the like to form the conductor pattern. The conductor pattern formation based on the subtractive method can be performed in accordance with a publicly known procedure. For example, the conductor pattern formation based on the subtractive method can be performed by a method including the following steps: i) a step of providing a plating seed layer on the surface of the substrate by electroless plating; ii) a step of forming a conductor layer by providing a metal layer on the plating seed layer by electrolytic plating; iii) a step of providing a resist layer (dry film) on the surface of the conductor layer; iv) a step of forming a wiring pattern by exposing and developing the resist layer; v) a step of etching and removing the exposed conductor layer; and vi) a step of removing the resist layer.

[0199] Further, in the semi-additive method, a non-circuit formation portion of the plated seed layer is protected by an anti-plating layer, and after the circuit formation portion is thickened by electrolytic plating with a metal such as copper, the anti-plating layer is removed, and the plated seed layer other than the circuit formation portion is removed by etching, to form a conductor pattern. The conductor pattern formation based on the semi-additive method can be performed according to a known procedure. For example, the conductor pattern formation based on the semi-additive method can be performed by a method including the following steps: i) a step of providing a plated seed layer on the surface of the substrate by electroless plating; ii) a step of providing an anti-plating layer (dry film) on the surface of the plated seed layer; iii) a step of forming a wiring pattern by exposing and developing the anti-plating layer; iv) a step of performing electrolytic plating through the anti-plating layer; v) a step of removing the anti-plating layer; and vi) a step of removing the plated seed layer other than the circuit formation portion by etching.

[0200] The first conductor pattern is not limited in structure (pattern) as long as it can form a conductor coil together with the via conductor and the second conductor pattern. For example, the first conductor pattern can be formed of via pads 28a and connection patterns 28b connecting the via pads to each other Figure 1 The second conductor pattern is also similarly formed of via pads 29a and connection patterns 29b connecting the via pads to each other Figure 1 , the via pads 29a are not shown).

[0201] The first conductor pattern and the second conductor pattern are connected by the via conductor to form a solenoid-shaped conductor pattern (conductor coil). Thus, an inductor function is exerted.

[0202] As described above, the matter that the first conductor pattern is formed on the "first main surface of the magnetic body layer" includes a case where the first conductor pattern is provided on the first main surface of the magnetic body layer in bonding (directly), and further includes a case where the first conductor pattern is provided on the first main surface of the magnetic body layer through another layer. The matter that the second conductor pattern is formed on the "second main surface of the magnetic body layer" also similarly includes a case where the second conductor pattern is provided on the second main surface of the magnetic body layer in bonding (directly), and further includes a case where the second conductor pattern is provided on the second main surface of the magnetic body layer through another layer.

[0203] An embodiment (also referred to as "first embodiment") in which the above-described procedures (A) to (G) are performed in such a manner that the first conductor pattern and the second conductor pattern are provided on the first main surface and the second main surface of the magnetic body layer in bonding (directly), respectively, can manufacture the wiring substrate 100 shown in FIG. 1. Figure 8 The wiring substrate 100 shown in FIG. 1 is manufactured by the above-described procedure (A) to (G) in which the first conductor pattern 28 and the second conductor pattern 29 are provided on the first main surface and the second main surface of the magnetic body layer 22 in bonding, respectively. Figure 8 In the wiring substrate 100 shown in FIG. 1, the first conductor pattern 28 and the second conductor pattern 29 are provided in bonding with the first main surface and the second main surface of the magnetic body layer 22, respectively.

[0204] On the other hand, the above procedures (A) to (G) can be implemented in such a manner that the first conductor pattern and the second conductor pattern are provided on the first main surface and the second main surface of the magnetic layer with other layers interposed therebetween. Hereinafter, this implementation will also be referred to as "second implementation". As the other layers, there is no particular limitation as long as the effects of the present application are not hindered, and examples thereof include an insulating layer.

[0205] Hereinafter, for the second implementation, a preferred mode in which an insulating layer is used as the other layer will be described.

[0206] In the second implementation, the method for manufacturing the wiring substrate of the present application further includes at least one of the following procedure (D-1) and procedure (D-2) after the procedure (D):

[0207] (D-1) a procedure of providing an insulating layer in engagement with the first main surface of the inner layer substrate and the first main surface of the magnetic layer;

[0208] (D-2) a procedure of providing an insulating layer in engagement with the second main surface of the inner layer substrate and the second main surface of the magnetic layer.

[0209] The procedure (D-1) and / or the procedure (D-2) are not particularly limited as long as the insulating layer can be provided in engagement with the main surface of the substrate, and can be implemented by a publicly known method that can be used when the insulating layer of the wiring substrate is formed. For example, an insulating adhesive film having an insulating adhesive layer can be used, the insulating adhesive layer is laminated in engagement with the main surface of the substrate, and the insulating adhesive layer is thermally cured to provide the insulating layer.

[0210] For example, as shown in FIG. 10, both the procedure (D-1) and the procedure (D-2) can be implemented using an insulating adhesive film. Figure 9 Figure 9 In the second implementation, the method for manufacturing the wiring substrate of the present application further includes at least one of the following procedure (D-1) and procedure (D-2) after the procedure (D): Figure 6 As shown in FIG. 10, an insulating adhesive film 50 is laminated on both main surfaces of the substrate (the substrate in which the insulating body 24 is provided in the first through-hole of the magnetic layer 22) obtained by the procedure (D).

[0211] As the support 51, examples include a film formed of a plastic material, a metal foil, a release paper, and preferably a film formed of a plastic material, a metal foil.

[0212] In the case where a film formed of a plastic material is used, as the plastic material, examples include a polyester such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), an acrylic polymer such as polycarbonate (PC), polymethyl methacrylate (PMMA), a cyclic polyolefin, triacetyl cellulose (TAC), a polyether sulfide (PES), a polyether ketone, a polyimide, and the like.​

[0213] In the case of using a metal foil, as the metal foil, for example, a copper foil, an aluminum foil, or the like can be given, and a copper foil is preferable. As the copper foil, a foil formed of a single metal of copper, or a foil formed of an alloy of copper and another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, or the like) can be used.

[0214] The thickness of the support body is not particularly limited, and is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm.

[0215] The composition of the insulating adhesive layer 52 is not particularly limited, and only needs to be such that the cured product thereof has sufficient insulating properties. The insulating adhesive layer 52 can be composed of, for example, a resin composition containing a thermosetting resin, and further containing, as necessary, a curing agent, an inorganic filler, a curing accelerator, a thermoplastic resin, an organic filler, a flame retardant, or the like. As the thermosetting resin, the curing agent, the inorganic filler, the curing accelerator, and the thermoplastic resin, the same substances as those described with respect to the magnetic material paste and the insulating via-filling paste can be used. With respect to the insulating adhesive layer used for forming the insulating layer of the wiring substrate, a large number of reports have been made, for example, in Japanese Patent Application Publication No. 2018-100421, Japanese Patent Application Publication No. 2017-171925, Japanese Patent Application Publication No. 2016-20480, and the like, and in the present application, these known insulating adhesive layers can be used as appropriate in accordance with the desired properties.

[0216] The thickness of the insulating adhesive layer 52 also depends on the specific design of the wiring substrate, and from the viewpoint of thinness, is preferably 100 μm or less, more preferably 80 μm or less, and further more preferably 60 μm or less or 50 μm or less. The lower limit of the thickness of the insulating adhesive layer 52 can generally be set to 5 μm or more, 10 μm or more, or the like.

[0217] The lamination of the insulating adhesive film 50 and the substrate can be performed by a vacuum lamination method. In the vacuum lamination method, the heating and pressure bonding temperature is preferably in the range of 60°C to 160°C, and more preferably in the range of 80°C to 140°C, the heating and pressure bonding pressure is preferably in the range of 0.098 MPa to 1.77 MPa, and more preferably in the range of 0.29 MPa to 1.47 MPa, and the heating and pressure bonding time is preferably in the range of 20 seconds to 400 seconds, and more preferably in the range of 30 seconds to 300 seconds. The lamination is preferably performed under reduced pressure conditions of 26.7 hPa or less. The lamination can be performed by a commercially available vacuum laminator. As the commercially available vacuum laminator, for example, a vacuum press-type laminator manufactured by Seiko Instruments Inc., a vacuum applicator manufactured by Nikko-Materials Co., Ltd., or the like can be given.

[0218] After the lamination, the insulating adhesive layer 52 is thermally cured to form an insulating layer. The thermal curing conditions of the insulating adhesive layer 52 can be the same as the thermal curing conditions of the magnetic material paste and the insulating via-filling paste.

[0219] The support body 51 can be peeled off before the thermal curing of the insulating adhesive layer, or can be peeled off after the thermal curing of the insulating adhesive layer. Alternatively, in the case where a metal foil is used as the support body 51, the metal foil can be used to form the first and second conductor patterns without peeling off and removing the metal foil. Hereinafter, the embodiment in which the support body is peeled off and the embodiment in which the conductor patterns are formed using the support body metal foil are described separately.

[0220] Embodiment in which the support body is peeled off

[0221] In the case where the support body 51 is peeled off, the wiring substrate 200 shown in FIG. 10 is obtained. Figure 10 The wiring substrate shown in FIG. 10 is obtained. Figure 10 In the wiring substrate shown in FIG. 10, the insulating layer 34 is provided in adhesion on the first and second main surfaces of the inner layer substrate 20 and the magnetic body layer 22. Note that, Figure 10 In the wiring substrate shown in FIG. 10, the insulating layer 34 is provided in adhesion on the first and second main surfaces of the inner layer substrate 20 and the magnetic body layer 22. Note that, Figure 9 ) of the insulating member from the insulating body 24( ) of the insulating member from the insulating body 24(

[0222] ) of the insulating member from the insulating body 24( Figure 11 ) of the insulating member from the insulating body 24( Figure 9 Figure 10 ) of the insulating member from the insulating body 24(

[0223] By performing the process (F) after the formation of the second through-holes, the through-hole conductors 36 can be formed inside the second through-holes 35. Then, by performing the process (G), the first and second conductor patterns 38 and 39 and the through-hole conductors 36 can be connected to form a solenoid-shaped conductor pattern (conductor coil). Thus, the wiring substrate 200 shown in FIG. 10 is obtained. In the wiring substrate 200, the first conductor pattern 38 is provided in adhesion on the surface of the insulating layer 34 on the first main surface of the magnetic body layer 22, and the second conductor pattern 39 is provided in adhesion on the surface of the insulating layer 34 on the second main surface of the magnetic body layer 22. Figure 12 Embodiment in which the conductor patterns are formed using the support body metal foil

[0224] In the case where a metal foil is used as the support body 51, the metal foil can be used to form the first and second conductor patterns without peeling off and removing the metal foil.

[0225]

[0226] ​Through the above implementation method, obtain Figure 13 The substrate shown. Figure 13 In the substrate shown, an insulating layer 34 is provided on the first and second main surfaces of the inner substrate 20 and the magnetic layer 22, and a support metal foil 51 is provided in connection with the insulating layer 34. It should be noted that... Figure 13 Zhongyi and Figure 10 Similarly, it is shown that "the material from the insulator 24 is disposed in the first through hole of the magnetic layer 22". Figure 9 The insulating components 24 and the insulating layer 34 obtained by heat curing the insulating resin layer 52 are not distinguished, but the composition of the insulating body 24 and the composition of the insulating layer 34 can be the same or different.

[0227] Process (E) can be performed on the substrate. In this embodiment, in process (E), a second through hole 45 is formed that not only penetrates the insulator 24, but also penetrates the insulating layer 34 and the support metal foil 51. Figure 14 Also refer to Figure 9 , Figure 13 The number and size of the second through holes, and the spacing between the second through holes, are as described above.

[0228] After forming the second through-hole, step (F) is performed to form a through-hole conductor 46 inside the second through-hole 45. Then, by performing step (G), the first conductor pattern 48, the second conductor pattern 49, and the through-hole conductor 46 are connected to form a solenoid-shaped conductor pattern (conductor coil). In step (G), the first conductor pattern 48 and the second conductor pattern 49 can be formed using a support metal foil 51 and conductor pattern forming techniques such as subtractive processing or semi-additive processing (modified semi-additive processing). For example, in the subtractive processing, the conductor pattern is formed by selectively removing unwanted portions (non-circuit forming portions) of the support metal foil by etching or the like. For example, conductor pattern formation based on the subtractive processing can be performed by a method including the following steps: i) providing a resist layer (dry film) on the surface of the support metal foil; ii) exposing and developing the resist layer to form a wiring pattern; iii) etching away the exposed support metal foil; iv) removing the resist layer. Furthermore, in the semi-additive processing, the support metal foil can be used as a seed layer to form the conductor pattern. For example, conductor pattern formation based on the semi-additive method can be carried out by a method including the following steps: i) a step of forming a resist layer (dry film) on the surface of a support metal foil (coated seed layer); ii) a step of exposing and developing the resist layer to form a wiring pattern; iii) a step of electroplating the resist layer; iv) a step of removing the resist layer; v) a step of etching away the support metal foil except for the circuit forming part.

[0229] Therefore, obtain Figure 15The wiring substrate 300 is shown. In the wiring substrate 300, a first conductor pattern 48 is disposed on the first main surface of the magnetic layer 22 and is bonded to the surface of the insulating layer 34, while a second conductor pattern 49 is disposed on the second main surface of the magnetic layer 22 and is bonded to the surface of the insulating layer 34.

[0230] When an insulating layer 34 is provided at the junction of at least one of the main surfaces of the first and second main surfaces of the inner substrate 20 ( Figure 12 and Figure 15 The method for manufacturing a wiring substrate according to the present invention further includes a step of depositing a conductor layer in contact with the surface of the insulating layer. Therefore, in one embodiment, the method for manufacturing a wiring substrate according to the present invention further includes a step of depositing a conductor layer on the surface of an insulating layer on at least one of the main surfaces of a first main surface and a second main surface of an inner layer substrate.

[0231] Furthermore, the method for manufacturing the wiring substrate of the present invention may further include a step of alternately disposing insulating layers and conductor layers (wiring layers) on at least one of the main surfaces of the first and second main surfaces of the inner layer substrate 20 (and the magnetic layer 22) to form multilayer wiring. Regarding the specific design of the insulating layers and wiring layers, and the multilayer wiring, layer configurations and designs known in the manufacture of wiring substrates can be adopted. For example, by using… Figure 8 , Figure 12 and Figure 15 The wiring substrate shown serves as an inner circuit substrate, on which insulating layers and conductor layers are alternately disposed, thereby enabling the fabrication of a wiring substrate with multi-layer wiring that incorporates a sensor structure. Example

[0232] The present invention will now be specifically described with reference to the embodiments shown below. However, the present invention is not limited to the embodiments shown below.

[0233] [Example 1]

[0234] 1-A. Preparation for forming an inner layer substrate with openings

[0235] Prepare an inner layer substrate ("MCL-E-705GL", copper foil etchout, manufactured by Hitachi Chemical Co., Ltd.) with a thickness of 0.8 mm. Form a circular opening with a diameter of 1.4 mm on this inner layer substrate using a drill bit. The opening is formed using a "ST" drill bit manufactured by Union Tool Co., Ltd., at a rotation speed of 46,000 rpm.

[0236] 1-B. Formation of the Magnetic Layer

[0237] A magnetic material paste was vacuum printed in an opening having a diameter of 1.4 mm. The magnetic material paste was a material having a content of magnetic powder of 90 mass%, a viscosity of 60 Pa-s (a measurement environment of an E-type viscometer at 25°C, 5 rpm), and a relative magnetic permeability of 7 at 100 MHz. After vacuum printing, the magnetic material paste was heat cured by heating at 130°C for 30 minutes and further heating at 145°C for 30 minutes, thereby providing a magnetic material layer inside the opening. Subsequently, the surface of the inner layer substrate and the magnetic material layer was polished to be smoothed. As to the polishing, a ceramic polishing roll #1500 manufactured by Shikisai Table Co., Ltd. was used.

[0238] 1-C. Formation of first through hole

[0239] A first through hole having a diameter of 0.3 mm was formed in the magnetic material layer using a drill bit having a diameter of 1.4 mm. As shown in FIG. 1C, four first through holes (left-right interval of 0.6 mm, upper-lower interval of 0.5 mm) were formed. As to the first through hole, a drill bit "UV" manufactured by Yuki Tool Co., Ltd. was used to form at a rotation speed of 60,000 rpm. Figure 1

[0240] 1-D. Formation of insulator

[0241] An insulating hole-filling paste ("IR-10F", manufactured by San-Ei Chemical Industry, Co., Ltd.) was vacuum printed in the first through hole having a diameter of 0.3 mm. After vacuum printing, the insulating hole-filling paste was heat cured by heating at 110°C for 30 minutes and further heating at 150°C for 60 minutes, thereby obtaining an insulator inside the first through hole. Subsequently, the surface of the insulator was polished to be smoothed. As to the polishing, a ceramic polishing roll #1500 manufactured by Shikisai Table Co., Ltd. was used.

[0242] 1-D'. Formation of insulating layer

[0243] Subsequently, an insulating adhesive film ("ABF-GX92R", insulating resin layer thickness of 30 μm, support PET, manufactured by Ajinomoto Fine-Techno Co., Ltd.) was vacuum laminated to both surfaces of the substrate so that the insulating resin layer was bonded to the surface of the substrate. After vacuum lamination, the insulating resin layer was heat cured by heating at 100°C for 30 minutes and further heating at 180°C for 30 minutes, thereby obtaining an insulating layer.

[0244] 1-E. Formation of second through hole

[0245] ​A second through-hole (n = 4) having a diameter of 0.15 mm was formed in the insulator having a diameter of 0.3 mm using a drill. With respect to the second through-hole, the position was aligned under the condition that the center thereof coincided with the center of the first through-hole (insulator having a diameter of 0.3 mm). With respect to the second through-hole, a drill "NEU" manufactured by Yueda Tool Co., Ltd. was used to form under the condition of a rotation speed of 80,000 rpm.

[0246] 1-F. Formation of Through-hole Conductor

[0247] After the inside of the second through-hole and the surface of the substrate were subjected to a decontamination treatment, electrolytic plating (thickness: 22 μm) was performed to form a through-hole conductor (conformal type) in the second through-hole. After the through-hole conductor was formed in the second through-hole, an insulating via-filling paste ("IR-10F", manufactured by San-Ei Chemical Industry, Co., Ltd.) was vacuum-printed in the second through-hole. After the vacuum printing, the insulating via-filling paste was heat-cured by heating at 110°C for 30 minutes and further heating at 150°C for 60 minutes to provide an insulator. Subsequently, the surface of the insulator was polished to be smoothed. With respect to the polishing, a ceramic polishing roller #1500 manufactured by Shikiei Table Co., Ltd. was used.

[0248] 1-G. Formation of Spiral Coil-shaped Conductor Pattern

[0249] After the surface of the substrate was subjected to a decontamination treatment, electrolytic plating (thickness: 22 μm) was performed to form a conductor layer. A dry film was laminated on the conductor layer, and exposure and development were performed to form a pattern in the dry film. Subsequently, the dry film was peeled off after a conductor pattern was formed by a subtractive method using an iron chloride etching solution. The conductor pattern was formed on both surfaces of the substrate as shown in FIG. 1G. That is, the surface conductor pattern was formed in such a manner that the surface conductor pattern and the through-hole conductor were connected in a spiral coil shape, and a sensor structure was built in the wiring substrate. Figure 1

[0250] [Example 2]

[0251] 2-A. Preparation of Inner Layer Substrate Having Openings

[0252] An inner layer substrate ("MCL-E-705GL", copper foil etching product, manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 0.8 mm was prepared. A circular opening having a diameter of 1.4 mm was formed in the inner layer substrate using a drill. With respect to the opening, a drill "ST" manufactured by Yueda Tool Co., Ltd. was used to form under the condition of a rotation speed of 46,000 rpm.

[0253] 2-B. Formation of Magnetic Body Layer

[0254] ​A magnetic material paste was vacuum printed in an opening having a diameter of 1.4 mm. The magnetic material paste was a material having a content of magnetic powder of 90 mass%, a viscosity of 60 Pa-s (a measurement environment of an E-type viscometer at 25°C, 5 rpm), and a relative magnetic permeability of 7 at 100 MHz. After vacuum printing, the magnetic material paste was heat cured by heating at 130°C for 30 minutes and then at 145°C for 30 minutes, thereby providing a magnetic material layer inside the opening. Next, the surface of the inner layer substrate and the magnetic material layer was polished to be smoothed. As to the polishing, a ceramic polishing roll #1500 manufactured by Shikiso Table Co., Ltd. was used.

[0255] 2-C. Formation of first through hole

[0256] A first through hole having a diameter of 0.3 mm was formed in the magnetic material layer using a drill bit having a diameter of 1.4 mm. As shown in FIG. 2C, four first through holes (left-right interval of 0.6 mm, upper-lower interval of 0.5 mm) were formed. As to the first through hole, a drill bit "UV" manufactured by Yoko Tool Co., Ltd. was used to form at a rotation speed of 60,000 rpm. Figure 1

[0257] 2-D. Formation of insulator

[0258] An insulating hole-filling paste ("IR-10F", manufactured by San-Aidou Co., Ltd.) was vacuum printed in the first through hole having a diameter of 0.3 mm. After vacuum printing, the insulating hole-filling paste was heat cured by heating at 110°C for 30 minutes and then at 150°C for 60 minutes, thereby obtaining an insulator inside the first through hole. Next, the surface of the insulator was polished to be smoothed. As to the polishing, a ceramic polishing roll #1500 manufactured by Shikiso Table Co., Ltd. was used.

[0259] 2-D'. Formation of insulating layer

[0260] Next, an insulating adhesive film ("ABF-GX92R-RCC", insulating resin layer thickness of 30 μm, support copper foil, manufactured by Ajinomoto Fine-Techno Co., Ltd.) was vacuum laminated to both surfaces of the substrate so that the insulating resin layer was bonded to the surface of the substrate. After vacuum lamination, the insulating resin layer was heat cured by heating at 100°C for 30 minutes and then at 180°C for 30 minutes, thereby obtaining an insulating layer.

[0261] 2-E. Formation of second through hole

[0262] ​A second through-hole (n = 4) having a diameter of 0.15 mm was formed in the insulator having a diameter of 0.3 mm using a drill. With respect to the second through-hole, the position was aligned under the condition that the center thereof coincided with the center of the first through-hole (insulator having a diameter of 0.3 mm). With respect to the second through-hole, a drill "NEU" manufactured by Yonex Tool Co., Ltd. was used to form under the condition of a rotation speed of 80,000 rpm.

[0263] 2-F. Formation of Through-Hole Conductor

[0264] After the inside of the second through-hole and the surface of the substrate were subjected to a decontamination treatment, electrolytic plating (thickness: 22 μm) was performed to form a through-hole conductor (conformal type) in the second through-hole. After the through-hole conductor was formed in the second through-hole, an insulating via-filling paste ("IR-10F", manufactured by San-Aid Co., Ltd.) was vacuum-printed in the second through-hole. After the vacuum printing, the insulating via-filling paste was heat-cured by heating at 110°C for 30 minutes and further heating at 150°C for 60 minutes to provide an insulator. Subsequently, the surface of the insulator was polished to be smoothed. With respect to the polishing, a ceramic polishing roll #1500 manufactured by Ishii Hyomen Co., Ltd. was used.

[0265] 2-G. Formation of Spiral-Coil-Type Conductor Pattern

[0266] After the surface of the substrate was subjected to a decontamination treatment, electrolytic plating (thickness: 22 μm) was performed to form a conductor layer together with a support copper foil. A dry film was laminated on the conductor layer, and exposure and development were performed to form a pattern in the dry film. Subsequently, the dry film was peeled off after a conductor pattern was formed by a subtractive method using an iron chloride etching solution. The conductor pattern was formed on both surfaces of the substrate as shown in FIG. 2G. That is, the surface conductor pattern was formed in such a manner that the surface conductor pattern and the through-hole conductor were connected in a spiral-coil type, and a sensor structure was built in the wiring substrate. Figure 1

[0267] [Example 3]

[0268] 3-A. Preparation of Inner Layer Substrate Having Opening

[0269] An inner layer substrate ("MCL-E-705GL", copper foil etching product, manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 0.8 mm was prepared. A circular opening having a diameter of 1.4 mm was formed in the inner layer substrate using a drill. With respect to the opening, a drill "ST" manufactured by Yonex Tool Co., Ltd. was used to form under the condition of a rotation speed of 46,000 rpm.

[0270] 3-B. Formation of Magnetic Body Layer

[0271] ​Magnetic paste was vacuum-printed through an opening with a diameter of 1.4 mm. The magnetic paste used was a material with a magnetic powder content of 90% by mass, a viscosity of 60 Pa·s (E-type viscometer, measured at 25°C and 5 rpm), and a relative permeability of 7 at 100 MHz. After vacuum printing, the paste was heated at 130°C for 30 minutes, and then at 145°C for 30 minutes to thermally solidify it, thus creating a magnetic layer inside the opening. Next, the surfaces of the inner substrate and the magnetic layer were polished to smooth them. Polishing was performed using a ceramic polishing roller #1500 manufactured by Ishii Optoelectronics Co., Ltd.

[0272] 3-C. Formation of the first through hole

[0273] A first through hole with a diameter of 0.3 mm is formed in a magnetic layer with a diameter of 1.4 mm using a drill bit. For example... Figure 1 As shown, four first through holes were formed (0.6 mm horizontally and 0.5 mm vertically). The first through holes were formed using a "UV" drill bit manufactured by Yuno Tools Co., Ltd. at a rotation speed of 60,000 rpm.

[0274] 3-D. Formation of Insulators

[0275] Insulating filler paste (“IR-10F”, manufactured by Sanei Chemical Co., Ltd.) was vacuum-printed into the first through-hole with a diameter of 0.3 mm. After vacuum printing, the paste was heated at 110°C for 30 minutes, and then at 150°C for 60 minutes to thermally solidify the insulating filler paste and form an insulator inside the first through-hole. Next, the surface of the insulator was polished to smooth it. Polishing was performed using a ceramic polishing roller #1500 manufactured by Ishii Optical Co., Ltd.

[0276] 3-E. Formation of the second through hole

[0277] Four second through holes (n=4) with a diameter of 0.15 mm were drilled in each of the 0.3 mm diameter insulators. The second through holes were aligned so that their centers coincided with the center of the first through hole (insulator with a diameter of 0.3 mm). The second through holes were drilled using a NEU drill bit manufactured by Yuno Tools Co., Ltd., at a rotation speed of 80,000 rpm.

[0278] 3-F. Formation of Through-Hole Conductors

[0279] After the inside of the second through-hole and the surface of the substrate were subjected to a desmear treatment, electroless plating (thickness 0.7 μm) and electrolytic plating (thickness 22 μm) were performed to form a through-hole conductor (conformal type) in the second through-hole. After the through-hole conductor was formed, an insulating via-filling paste ("IR-10F", manufactured by Yamaguchi Chemical Industry Co., Ltd.) was vacuum-printed in the second through-hole. After vacuum printing, the insulating via-filling paste was heat-cured by heating at 110°C for 30 minutes and then at 150°C for 60 minutes to provide an insulator. Next, the surface of the insulator was polished to be smooth. For polishing, a ceramic polishing roller #1500 manufactured by Ishii Hyomen Co., Ltd. was used.

[0280] 3-G. Formation of the Spiral Coil Type Conductor Pattern

[0281] After the surface of the substrate was subjected to a desmear treatment, electroless plating (thickness 0.7 μm) and electrolytic plating (thickness 22 μm) were performed to form a conductor layer. A dry film was laminated on the conductor layer, and exposure and development were performed to pattern the dry film. Next, after a conductor pattern was formed by a subtractive method using an iron chloride etching solution, the dry film was peeled off. The conductor pattern was formed on both surfaces of the substrate as shown in FIG. 3G. That is, it was formed in such a manner that the surface conductor pattern of the substrate was connected to the through-hole conductor in a spiral coil type, and a sensor structure was built in the wiring substrate. Figure 1

[0282] Explanation of Symbols

[0283] 10, 10': Sensor Structure Part

[0284] 20: Inner Layer Substrate

[0285] 20a: First Main Surface

[0286] 20b: Second Main Surface

[0287] 21: Opening (First Opening)

[0288] 22: Magnetic Body Layer

[0289] 23: First Through-Hole (Second Opening)

[0290] 24: Insulator

[0291] 25, 35, 45: Second Through-Hole (Third Opening)

[0292] 26, 36, 46: Through-Hole Conductor

[0293] 27, 37, 47: Insulator (Inside of Conformal Through-Hole Conductor)

[0294] 28, 38, 48: First Conductor Pattern

[0295] 28a: Through-Hole Pad​

[0296] 28b: connection pattern

[0297] 29, 39, 49: second conductor pattern

[0298] 29a: via land (not shown)

[0299] 29b: connection pattern

[0300] 34: insulating layer

[0301] 50: insulating adhesive film

[0302] 51: support

[0303] 52: insulating resin layer

[0304] 100, 200, 300: wiring substrate

Claims

1. A wiring board having an inductor function, comprising: an inner layer substrate having a first main surface and a second main surface, and formed with an opening through between the first main surface and the second main surface; a magnetic body layer which is a magnetic body layer provided inside the opening, and formed with a first via hole through a first main surface and a second main surface thereof; an insulator which is an insulator provided inside the first via hole, and formed with a second via hole through the insulator; and an inductor formed of a first conductor pattern formed on the first main surface of the magnetic body layer, a second conductor pattern formed on the second main surface of the magnetic body layer, and a via conductor provided inside the second via hole and connecting the first conductor pattern and the second conductor pattern, the first conductor pattern being directly provided in bonding on the first main surface of the magnetic body layer, the second conductor pattern being directly provided in bonding on the second main surface of the magnetic body layer. The magnetic body layer has a plurality of first via holes through the first main surface and the second main surface thereof. The first conductor pattern and the second conductor pattern are connected by the via conductor to form a solenoid-shaped conductor pattern. The solenoid-shaped conductor pattern is provided inside a region of the magnetic body layer as viewed in a direction perpendicular to the main surface of the wiring board. The inner layer substrate is an insulating substrate. The inner layer substrate is a circuit substrate. The opening through the first main surface and the second main surface of the inner layer substrate is rectangular, and has a size of 0.5 mm x 0.5 mm or more.

2. The wiring substrate according to claim 1, wherein The size of the opening is 5 mm x 5 mm or less.

3. The wiring substrate according to claim 1, wherein The opening through the first main surface and the second main surface of the inner layer substrate is circular, and has a diameter of 0.5 mm or more.

4. The wiring substrate according to claim 3, wherein The diameter of the opening is 5 mm or less.

5. The wiring substrate according to claim 1, wherein When a diameter of the first via hole is Dl, a distance from a center position of the first via hole to the inner layer substrate is 0.7Dl or more.

6. The wiring substrate according to claim 1, wherein When the diameter of the first via hole is Dl, the distance from the center position of the first via hole to the inner layer substrate is Dl or more.

7. The wiring substrate according to claim 1, wherein 13. A manufacturing method of the wiring board having an inductor function according to any one of claims 1 to 12, comprising the following steps (A) to (G): (A) a step of preparing an inner layer substrate having a first main surface and a second main surface, and formed with an opening through between the first main surface and the second main surface; (B) a step of filling a magnetic body paste inside the opening, and thermally curing the magnetic body paste to provide a magnetic body layer; (C) a step of forming a first via hole through between the first main surface and the second main surface of the magnetic body layer; (D) a step of providing an insulator inside the first via hole; (E) a step of forming a second via hole through the insulator; (F) a step of forming a via conductor inside the second via hole; and (G) a step of forming a first conductor pattern and a second conductor pattern on the first main surface and the second main surface of the magnetic body layer, respectively, in such a manner that the first conductor pattern and the second conductor pattern are connected in a solenoid shape by the via conductor.

8. The wiring substrate according to claim 7, wherein In the step (G), the first conductor pattern is provided in bonding on the first main surface of the magnetic body layer.

9. The wiring substrate according to claim 1, wherein In the step (G), the second conductor pattern is provided in bonding on the second main surface of the magnetic body layer.

10. The wiring substrate according to claim 9, wherein ​ 11. The wiring substrate according to claim 1, wherein ​ 12. The wiring substrate according to claim 1, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ 14. The method of claim 13, wherein, ​ 15. The method of claim 13, wherein, ​ 16. The method of claim 13, wherein, The viscosity of the magnetic material slurry at 25±2°C is 20 to 250 Pa-s.

17. The method of claim 16, wherein, The viscosity of the magnetic material slurry at 25±2°C is 40 Pa-s or more.

18. The method of claim 16, wherein, The viscosity of the magnetic material slurry at 25±2°C is 200 Pa-s or less.

19. The method of claim 13, wherein, In the process (C), a plurality of first through holes are formed through the magnetic material layer between the first main surface and the second main surface.

20. The method of claim 13, wherein, A solenoid-shaped conductor pattern is formed inside the region of the magnetic material layer from a direction perpendicular to the main surface of the wiring substrate.

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