阅读说明：本技术 布线电路基板及其制造方法 (Wired circuit board and method for manufacturing same ) 是由 奥村圭佑 古川佳宏 于 2019-03-14 设计创作，主要内容包括：本发明提供布线电路基板。布线电路基板具有：第1绝缘层；布线,其配置于第1绝缘层的厚度方向一面；第2绝缘层,其覆盖布线；以及粒子含有层,该粒子含有层含有呈纵横比为2以上的形状的导电性粒子,且该粒子含有层隔着第2绝缘层覆盖布线。布线呈大致弯曲形状。(The invention provides a printed circuit board. The wired circuit board includes: 1 st insulating layer; a wiring disposed on one surface in the thickness direction of the 1 st insulating layer; a 2 nd insulating layer covering the wiring; and a particle-containing layer containing conductive particles having an aspect ratio of 2 or more, the particle-containing layer covering the wiring via the 2 nd insulating layer. The wiring is substantially curved.)

1. A printed circuit board comprising a printed circuit board,

the wired circuit board includes:

1 st insulating layer;

a wiring disposed on one surface in a thickness direction of the 1 st insulating layer;

a 2 nd insulating layer covering the wiring; and

a particle-containing layer containing conductive particles having an aspect ratio of 2 or more and covering the wiring with the insulating layer 2 interposed therebetween,

the wiring is substantially curved.

2. The wired circuit board according to claim 1,

the conductive particles are magnetic particles and the conductive particles are magnetic particles,

the particle-containing layer is a magnetic layer,

the wired circuit board is a magnetic wired circuit board.

3. The wired circuit board according to claim 2,

the 2 nd insulating layer is an electrodeposited layer.

4. The wired circuit board according to claim 2,

the 2 nd insulating layer has an average thickness T of 10 [ mu ] m or less.

5. The wired circuit board according to claim 2,

the wiring has: a first insulating layer 1 facing the first insulating layer in the thickness direction; a second surface in the thickness direction, which is in contact with the first surface in the thickness direction of the first insulating layer 1; and a side surface connecting both end edges of the one surface in the thickness direction and the other surface in the thickness direction together,

the 2 nd insulating layer covers the thickness direction one face and the side face,

the wiring has a corner portion formed by the thickness direction one surface and the side surface,

the corner portion has a substantially curved shape.

6. The wired circuit board according to claim 5,

the corner has a radius of curvature R of 9 μm or more.

7. The wired circuit board according to claim 5,

the magnetic layer covers a portion of the thickness direction one surface of the 1 st insulating layer exposed from the 2 nd insulating layer,

the wiring has a 2 nd corner formed by the other surface in the thickness direction and the side surface,

the 2 nd corner portion has a portion in which a length between the two side surfaces opposed to each other becomes longer as approaching the other side in the thickness direction.

8. The wired circuit board according to claim 2,

the wiring is in the shape of a substantially circular shape,

the 2 nd insulating layer covers a circumferential surface of the wiring,

the particle-containing layer covers the peripheral surface of the wiring with the second insulating layer 2 interposed therebetween.

9. A method for manufacturing a printed circuit board, characterized in that,

the method for manufacturing the wired circuit board includes:

a 1 st step of preparing a 1 st insulating layer and a wiring disposed on one surface in a thickness direction of the 1 st insulating layer;

a 2 nd step of covering the wiring with a 2 nd insulating layer in the 2 nd step; and

a 3 rd step of forming a particle-containing layer in the 3 rd step, the particle-containing layer covering the wiring with the 2 nd insulating layer interposed therebetween, the particle-containing layer containing conductive particles having an aspect ratio of 2 or more,

the wiring is formed in a substantially curved shape,

in the 2 nd step, a particle-containing sheet containing the conductive particles oriented in a direction orthogonal to the thickness direction is hot-pressed against the 2 nd insulating layer.

10. The method of manufacturing a wired circuit board according to claim 9,

the conductive particles are magnetic particles and the conductive particles are magnetic particles,

the particle-containing layer is a magnetic layer,

the particle-containing sheet is a magnetic sheet,

the method for manufacturing the wired circuit board is a method for manufacturing a magnetic wired circuit board.

11. The method of manufacturing a wired circuit board according to claim 10,

the wiring in the step 1 includes: a first insulating layer 1 facing the first insulating layer in the thickness direction; a second surface in the thickness direction, which is in contact with the first surface in the thickness direction of the first insulating layer 1; and a side surface which connects both end edges of the first surface in the thickness direction and the second surface in the thickness direction and which forms a corner portion having a substantially curved shape with the side surface,

in the step 2, the one surface and the side surfaces of the wiring in the thickness direction are covered with the insulating layer,

in the 3 rd step, a particle-containing layer is formed to cover the one surface and the side surface of the wiring in the thickness direction with the insulating layer 2 interposed therebetween.

12. The method of manufacturing a wired circuit board according to claim 11,

the step 1 includes:

a 4 th step of forming a wiring base portion having a tip portion formed by one surface and a side surface in a thickness direction of the wiring base portion by a subtractive method; and

and a 5 th step of forming a plating layer covering the wiring base portion by plating, the plating layer having a covering portion covering the tip portion, so that the corner portion is formed into a substantially curved shape from the covering portion.

13. The method of manufacturing a wired circuit board according to claim 10,

the wiring in the step 1 is substantially circular,

in the step 2, the peripheral surface of the wiring is covered with the insulating layer,

in the 3 rd step, a particle-containing layer is formed to cover the peripheral surface of the wiring with the 2 nd insulating layer interposed therebetween.

Technical Field

The present invention relates to a wired circuit board and a method for manufacturing the same.

Background

Conventionally, it is known to use a coil module for wireless communication and wireless power transmission in which power is transmitted wirelessly.

For example, a coil module having a coil pattern and a magnetic layer in which the coil pattern is embedded and which contains flat magnetic particles (conductive particles) has been proposed (for example, see patent document 1).

Such a coil module is obtained, for example, by: first, a coil pattern is formed by conductor patterning, and then, a magnetic sheet containing magnetic particles is hot-pressed against the coil pattern.

Disclosure of Invention

Problems to be solved by the invention

However, a large current may flow through the coil pattern, and in this case, the flat magnetic particles contained in the insulating layer may short circuit the coil patterns, and thus insulation between the coil patterns and the magnetic layer is required.

Therefore, a proposal of forming an insulating layer between the coil pattern and the magnetic layer has been tried.

However, since the ridge line portions on the upper surface and the side surfaces of the coil pattern are formed with the tip portions that are tapered obliquely upward and laterally (outward), in this case, if the insulating layer is formed, the thickness of the insulating layer facing the tip portions tends to become excessively thin. Therefore, when a magnetic sheet containing magnetic particles is thermally pressed against a coil pattern containing a tip portion via an insulating layer, the magnetic particles penetrate through the insulating layer facing the tip portion and come into contact with the tip portion, resulting in the following disadvantages: such contact does not ensure insulation between the magnetic layer and the coil pattern.

On the other hand, the coil module also requires high inductance.

The invention provides a wired circuit board which can ensure the insulation of a particle-containing layer relative to a wiring and has high inductance and a manufacturing method thereof.

Means for solving the problems

The present invention (1) includes a wired circuit board including: 1 st insulating layer; a wiring disposed on one surface in a thickness direction of the 1 st insulating layer; a 2 nd insulating layer covering the wiring; and a particle-containing layer containing conductive particles having an aspect ratio of 2 or more, the particle-containing layer covering the wiring with the 2 nd insulating layer interposed therebetween, the wiring having a substantially curved shape.

In this wired circuit board, since the wiring has a substantially curved shape, the 2 nd insulating layer can be formed while suppressing the 2 nd insulating layer covering a portion of the wiring corresponding to the substantially curved shape from becoming excessively thin. Therefore, the conductive particles can be prevented from penetrating the 2 nd insulating layer and coming into contact with the wiring. As a result, the insulating property of the particle-containing layer with respect to the wiring can be secured by the 2 nd insulating layer.

Therefore, the wired circuit board can ensure insulation of the 2 nd insulating layer.

The present invention (2) is the wired circuit board according to (1), wherein the conductive particles are magnetic particles, the particle-containing layer is a magnetic layer, and the wired circuit board is a magnetic wired circuit board.

In a wired circuit board as a magnetic wired circuit board, in a magnetic layer covering a portion corresponding to a substantially curved shape in a wiring via a 2 nd insulating layer, magnetic particles having an aspect ratio of 2 or more can be oriented along the curved shape of the wiring. That is, the magnetic particles can be oriented in a direction inclined with respect to the thickness direction and the orthogonal direction in the magnetic layer opposed to the portion corresponding to the substantially curved shape in the wiring. Therefore, a smooth magnetic path along a portion of the magnetic layer corresponding to the substantially curved shape of the wiring can be formed. Therefore, the effective permeability around the wiring can be improved. As a result, the wired circuit board has high inductance.

Therefore, the wired circuit board has high inductance and can ensure insulation of the 2 nd insulating layer.

The invention (3) includes the wired circuit board described in (2), wherein the 2 nd insulating layer is an electrodeposition layer.

In this wired circuit board, since the 2 nd insulating layer is an electrodeposited layer, the thickness of the 2 nd insulating layer can be made thin. Therefore, a decrease in the effective permeability of the magnetic layer covering the wiring via such a 2 nd insulating layer can be suppressed. As a result, the wired circuit board has high inductance.

On the other hand, when the thickness of the 2 nd insulating layer is small, the magnetic particles easily penetrate the thin 2 nd insulating layer and come into contact with the wiring. However, in this wired circuit board, since the 2 nd insulating layer can be prevented from being formed in an excessively thin thickness in the 2 nd insulating layer covering the wiring having a substantially curved shape, the magnetic particles can be prevented from penetrating the 2 nd insulating layer, and the insulating property of the 2 nd insulating layer can be ensured.

The invention (4) is the wired circuit board according to (2) or (3), wherein the average thickness T of the 2 nd insulating layer is 10 μm or less.

In this wired circuit board, since the average thickness T of the 2 nd insulating layer is as thin as 10 μm or less, a decrease in the effective permeability of the magnetic layer can be suppressed. As a result, the wired circuit board has high inductance.

The present invention (5) is a wired circuit board according to any one of (2) to (4), wherein the wiring includes: a first insulating layer 1 facing the first insulating layer in the thickness direction; a second surface in the thickness direction, which is in contact with the first surface in the thickness direction of the first insulating layer 1; and a side surface that connects both end edges of the first surface in the thickness direction and the second surface in the thickness direction, wherein the 2 nd insulating layer covers the first surface in the thickness direction and the side surface, and the wiring has a corner portion formed by the first surface in the thickness direction and the side surface, and the corner portion has a substantially curved shape.

In this wired circuit board, since the corner portion of the wiring is formed in a substantially curved shape, the 2 nd insulating layer can be formed while suppressing the 2 nd insulating layer covering such corner portion from becoming excessively thin. Therefore, the conductive particles can be prevented from penetrating the 2 nd insulating layer and coming into contact with the corner portions of the wirings. As a result, the insulating property of the particle-containing layer with respect to the wiring can be secured by the 2 nd insulating layer. Therefore, the wired circuit board can ensure insulation of the 2 nd insulating layer.

The invention (6) includes the wired circuit board according to (5), wherein the corner portion has a radius of curvature R of 9 μm or more.

In this wired circuit board, when the radius of curvature R of the corner portion is large and 9 μm or more, the arc surface of the corner portion is gentle, and therefore, the 2 nd insulating layer corresponding to such a corner portion can be formed with a sufficient thickness. In addition, in the 2 nd magnetic layer opposed to the corner portion, the magnetic particles can be reliably oriented along the arc surface of the corner portion.

The invention (7) is the wired circuit board according to (5) or (6), wherein the magnetic layer covers a portion of the first insulating layer 1 exposed from the second insulating layer 2 on the one surface in the thickness direction, the wiring has a second corner portion formed by the second surface in the thickness direction and the side surface, and the second corner portion has a portion where a length between the two side surfaces facing each other becomes longer as approaching the second surface in the thickness direction.

In this wired circuit board, since the magnetic layer covers the portion of the thickness direction one surface of the 1 st insulating layer exposed from the 2 nd insulating layer, the magnetic particles in such a magnetic layer can be oriented in the orthogonal direction.

In addition, since the 2 nd corner formed by the other surface and the side surface in the thickness direction has a portion in which the length between the two side surfaces facing each other becomes longer as the other surface in the thickness direction comes closer, in the magnetic layer covering the portion through the 2 nd insulating layer, the magnetic particles can be oriented in a direction inclined with respect to the orthogonal direction in correspondence with the portion of the 2 nd corner.

Therefore, a smooth magnetic path can be formed around the 2 nd corner portion. Therefore, the wired circuit board has higher inductance.

The present invention (8) is the wired circuit board according to any one of (2) to (4), wherein the wiring is substantially circular, the 2 nd insulating layer covers a peripheral surface of the wiring, and the particle-containing layer covers the peripheral surface of the wiring with the 2 nd insulating layer interposed therebetween.

In the magnetic layer around the wiring, the magnetic particles can form a smooth magnetic path along the peripheral surface of the wiring. Therefore, the effective permeability around the wiring can be improved. As a result, the wired circuit board has high inductance.

The present invention (9) includes a method for manufacturing a wired circuit board, including: a 1 st step of preparing a 1 st insulating layer and a wiring disposed on one surface in a thickness direction of the 1 st insulating layer; a 2 nd step of covering the wiring with a 2 nd insulating layer in the 2 nd step; and a 3 rd step of forming a particle-containing layer in which the wiring is covered with the 2 nd insulating layer interposed therebetween and which contains conductive particles having an aspect ratio of 2 or more, the wiring being formed in a substantially curved shape, wherein in the 2 nd step, a particle-containing sheet containing the conductive particles oriented in a direction orthogonal to the thickness direction is hot-pressed against the 2 nd insulating layer.

However, in the 2 nd step, when the particle-containing sheet is thermally pressed against the 2 nd insulating layer, the conductive particles contained in the particle-containing sheet easily penetrate through the 2 nd insulating layer and come into contact with the wiring.

However, in this method for manufacturing a wired circuit board, since the wiring has a substantially curved shape in the 1 st step, the 2 nd insulating layer covering a portion of the wiring corresponding to the substantially curved shape can be formed thick.

Therefore, the conductive particles can be prevented from penetrating the 2 nd insulating layer and from coming into contact with the wiring.

Therefore, this manufacturing method can obtain a wired circuit board that ensures insulation of the 2 nd insulating layer.

The invention (10) includes the method for manufacturing a wired circuit board according to (9), wherein the conductive particles are magnetic particles, the particle-containing layer is a magnetic layer, and the method for manufacturing a wired circuit board is a method for manufacturing a magnetic wired circuit board.

In the 2 nd step of the method for manufacturing a wired circuit board, which is a method for manufacturing a magnetic wired circuit board, a magnetic sheet containing conductive particles oriented in a direction orthogonal to the thickness direction is thermally pressed against the 2 nd insulating layer, and therefore, in a magnetic layer covering a portion corresponding to a substantially curved shape in a wiring via the 2 nd insulating layer, the magnetic particles can be oriented along the curved shape of the wiring. That is, in the magnetic layer opposed to the portion corresponding to the substantially curved shape of the wiring, the magnetic particles can be oriented in a direction inclined with respect to the thickness direction and the orthogonal direction. Therefore, a smooth magnetic path along a portion of the magnetic layer corresponding to the substantially curved shape of the wiring can be formed. Therefore, the effective permeability around the wiring can be improved. As a result, a wired circuit board having high inductance can be manufactured.

The present invention (11) includes the method for manufacturing a wired circuit board according to (10), wherein the wiring in the step 1 includes: a first insulating layer 1 facing the first insulating layer in the thickness direction; a second surface in the thickness direction, which is in contact with the first surface in the thickness direction of the first insulating layer 1; and a side surface that connects both end edges of the first surface in the thickness direction and the second surface in the thickness direction, and that forms a corner portion having a substantially curved shape at the first surface in the thickness direction and the side surface, wherein in the 2 nd step, the first surface in the thickness direction and the side surface of the wiring are covered with the insulating layer, and in the 3 rd step, a particle-containing layer that covers the first surface in the thickness direction and the side surface of the wiring with the 2 nd insulating layer interposed therebetween is formed.

In this method for manufacturing a wired circuit board, since the wire in the 1 st step has a corner portion having a substantially curved shape, the 2 nd insulating layer covering such a corner portion can be formed thick.

Therefore, the conductive particles can be prevented from penetrating the 2 nd insulating layer and from coming into contact with the wiring.

Therefore, this manufacturing method can obtain a wired circuit board that ensures insulation of the 2 nd insulating layer.

The present invention (12) includes the method for manufacturing a wired circuit board according to (11), wherein the 1 st step includes: a 4 th step of forming a wiring base portion having a tip portion formed by one surface and a side surface in a thickness direction of the wiring base portion by a subtractive method; and a 5 th step of forming a plating layer covering the wiring base portion by plating, the plating layer having a covering portion covering the tip portion, so that the corner portion is formed into a substantially curved shape from the covering portion.

However, in the 1 st process, when a wiring having a tip portion is formed, in the 2 nd process, the thickness of an insulating layer opposite to the tip portion sometimes becomes excessively thin. Then, in the 3 rd step, when the magnetic layer is formed, the magnetic particles penetrate through the insulating layer facing the tip portion and come into contact with the tip portion, and as a result, there is a case where insulation between the magnetic layer and the wiring cannot be secured due to such contact.

However, even if the wiring base portion having the tip portion is formed in the 4 th step, the corner portion is formed into a substantially curved shape by the covering portion by forming the plating layer having the covering portion covering the tip portion in the 5 th step. Therefore, in the 2 nd step, the 2 nd insulating layer can be formed while suppressing the 2 nd insulating layer covering such corner portions from becoming excessively thin.

In the 3 rd step, the magnetic layer is formed, whereby the magnetic particles in the magnetic layer can be prevented from penetrating the 2 nd insulating layer and coming into contact with the wiring.

The present invention (13) includes the method for manufacturing a wired circuit board according to (10), wherein the wiring in the 1 st step is substantially circular, the peripheral surface of the wiring is covered with the insulating layer in the 2 nd step, and a particle-containing layer is formed in the 3 rd step, the particle-containing layer covering the peripheral surface of the wiring with the 2 nd insulating layer interposed therebetween.

In the 3 rd step, the magnetic particles can form a smooth magnetic path along the substantially curved shape of the wiring in the magnetic layer around the wiring. Therefore, the effective permeability around the wiring can be improved. As a result, a wired circuit board having high inductance can be manufactured.

ADVANTAGEOUS EFFECTS OF INVENTION

The wired circuit board of the present invention obtained by the method for manufacturing a wired circuit board of the present invention can ensure the insulation property of the 2 nd insulating layer.

Drawings

Fig. 1 shows a cross-sectional view of a magnetic wired circuit board according to an embodiment of the wired circuit board of the present invention and a partially enlarged cross-sectional view thereof.

Fig. 2A to 2D are process diagrams for manufacturing the magnetic wired circuit board shown in fig. 1, in which fig. 2A shows a 4 th step (a 1 st step) of forming a wiring base, fig. 2B shows a 5 th step (a 1 st step) of forming a plating layer and forming a wiring, fig. 2C shows a 2 nd step of forming a 2 nd insulating layer, and fig. 2D shows a 3 rd step of forming a magnetic layer.

Fig. 3 is a cross-sectional view illustrating a circle passing through the arc surface of the curved surface of the 1 st corner in fig. 1.

Fig. 4 is a partially enlarged cross-sectional view of a modification of the magnetic wired circuit board shown in fig. 1 (a configuration in which the plating layer is thin and the side surface of the wiring does not have a constricted portion).

Fig. 5 is a partially enlarged cross-sectional view of a modification (a mode in which the 2 nd corner portion has a vertical surface) of the magnetic wired circuit board shown in fig. 1.

Fig. 6 is a partially enlarged cross-sectional view of a modification (a mode in which the 2 nd corner portion has the 1 st narrowed surface) of the magnetic wired circuit board shown in fig. 1.

Fig. 7 is a partially enlarged cross-sectional view of a modification (a mode in which the 2 nd corner portion has a 2 nd narrowed surface) of the magnetic wired circuit board shown in fig. 1.

Fig. 8A to 8C are process diagrams of manufacturing a modification of the magnetic wired circuit board shown in fig. 1 (in which the wiring portion has a substantially circular cross section), fig. 8A shows a process of preparing the 1 st insulating layer, the wiring portion, and the 2 nd insulating layer, fig. 8B shows a process of disposing the wiring portion and the 2 nd insulating layer on the 1 st insulating layer, and fig. 8C shows a process of hot-pressing the magnetic sheet against the 1 st insulating layer, the wiring portion, and the 2 nd insulating layer.

Fig. 9A to 9B are process diagrams for manufacturing a magnetic wired circuit board according to a comparative example, in which fig. 9A shows a 2 nd step of forming a 2 nd insulating layer, and fig. 9B shows a 3 rd step of forming a magnetic layer.

Detailed Description

< one embodiment >

A magnetic wired circuit board 1 according to an embodiment of the wired circuit board of the present invention is described with reference to fig. 1.

The magnetic wired circuit board 1 has a first surface in a thickness direction and a second surface in the thickness direction opposed to each other in the thickness direction, and the magnetic wired circuit board 1 has a shape extending in a surface direction (a direction orthogonal to the thickness direction). The magnetic wired circuit board 1 includes a 1 st insulating layer 2 as an example of an insulating layer, a wiring portion 3 as an example of a wiring, a 2 nd insulating layer 4, and a magnetic layer 5 as an example of a particle-containing layer.

The 1 st insulating layer 2 has a shape extending in the planar direction. The 1 st insulating layer 2 is a support layer for supporting the wiring portion 3 described below, and is also a support layer for supporting the magnetic wired circuit board 1.

The 1 st insulating layer 2 has a 1 st insulating surface 7 as one surface in the thickness direction and a 2 nd insulating surface 8 as the other surface in the thickness direction. The 1 st insulating surface 7 and the 2 nd insulating surface 8 are flat surfaces along the surface direction, respectively. In addition, the 1 st insulating layer 2 has flexibility.

Examples of the material of the first insulating layer 2 include resins such as polyimide resin, polyester resin, and acrylic resin. In addition, the 1 st insulating layer 2 may be any of a single layer and a multilayer. The thickness of the first insulating layer 2 is not particularly limited, and is, for example, 1 μm or more and 1000 μm or less.

In the 1 st insulating surface 7 of the 1 st insulating layer 2, for example, a plurality of wiring portions 3 are arranged at intervals in the 1 st direction in a cut surface cut along the thickness direction and the 1 st direction (corresponding to the left-right direction in fig. 1 and including the plane direction). The shape of the wiring portion 3 in a plan view (when viewed in the thickness direction) is not particularly limited, and includes, for example, a ring shape (coil shape and the like).

The wiring portion 3 has: a 1 st wiring surface 9 which is a thickness direction surface facing the 1 st insulating surface 7 of the 1 st insulating layer 2 at a distance in the thickness direction; a 2 nd wiring surface 10 which is in contact with the 1 st insulating surface 7 of the 1 st insulating layer 2; and a wiring side surface 11 which connects both end edges in the 1 st direction of the 1 st wiring surface 9 and the 2 nd wiring surface 10.

The 1 st wiring surface 9 is a flat surface along the 1 st direction.

The 2 nd wiring surface 10 and the 1 st wiring surface 9 are arranged to face each other with a gap therebetween in the thickness direction, and the 2 nd wiring surface 10 is a flat surface parallel to the 1 st wiring surface 9.

The wiring side surface 11 extends in the thickness direction. The 1 wiring portion 3 has two wiring side surfaces 11. The two wiring side surfaces 11 are disposed so as to face each other (face each other) with a space therebetween in the 1 st direction.

The wiring portion 3 has a 1 st corner portion 21 and a 2 nd corner portion 22 as an example of the corner portions.

The 1 st corner 21 is a ridge portion (1 st ridge portion) formed by the 1 st wiring surface 9 and the wiring side surface 11 in the wiring portion 3. Specifically, the 1 st corner portion 21 is formed across each of both end portions of the 1 st wiring surface 9 in the 1 st direction and one end portion in the thickness direction of the wiring side surface 11 continuous thereto. The 1 st corner portion 21 is formed two per wiring portion 3.

The 1 st corner 21 has a substantially curved shape in cross section (a cross section along the thickness direction and the 1 st direction). Specifically, the 1 st corner portion 21 has a curved surface (more specifically, a substantially circular arc surface) 23 that bulges outward in the 1 st direction and toward one side in the thickness direction.

The center CP of the circle C forming the curved surface 23 (circular arc surface) is located, for example, inside the wiring portion 3.

The radius (radius of curvature) R of the circle C forming the curved surface 23 is, for example, 5 μm or more, preferably 9 μm or more, more preferably 15 μm or more, further preferably 20 μm or more, and further, for example, 30 μm or less. When the radius of curvature R of the curved surface 23 is equal to or greater than the lower limit described above, the curved surface 23 can be made gentle, and the 2 nd insulating layer 4 described below can be formed with a sufficient thickness T more reliably. In addition, the magnetic particles 18 (described later) can be reliably oriented along the curved surface 23 in the 2 nd insulating layer 4 facing the 1 st corner 21.

When the curvature radius R of the 1 st corner portion 21 is equal to or less than the upper limit described above, the magnetic layer 5 can be filled without a gap (air gap) in the central portion 50 (described later) of the wiring side surface 11 in the thickness direction.

The central angle α of the curved surface 23 is an angle formed by a line segment connecting one end of the circular arc and the center CP and a line segment connecting the other end of the circular arc and the center CP, and is, for example, less than 180 degrees. Specifically, the central angle α of the curved surface 23 is, for example, 45 degrees or more, preferably 60 degrees or more, more preferably 80 degrees or more, and is, for example, 150 degrees or less, preferably 135 degrees or less, more preferably 120 degrees or less. When the central angle α of the curved surface 23 is equal to or greater than the lower limit described above, the length of the curved surface 23 can be made longer, and therefore the magnetic particles 18 can be reliably aligned with the curved surface 23. When the central angle α of the curved surface 23 is equal to or greater than the lower limit described above, the length of the curved surface 23 can be made longer, and therefore the magnetic particles 18 can be reliably aligned with the curved surface 23. If the central angle α of the curved surface 23 is equal to or less than the upper limit, the magnetic layer 5 can be filled without a gap (clearance) in the central portion 50 (described later) in the thickness direction of the wiring side surface 11.

As shown in the enlarged view of fig. 1, the circle C forming the curved surface 23 has a center CP defined so as to form a circular arc passing (overlapping) the curved surface 23 at the 1 st corner 21 to the maximum extent, and is defined as a circle C based on such a center CP. On the other hand, the circle C' is not as follows: as shown in fig. 3, a circle C ' formed at the center CP ' of the arc passing (overlapping) the curved surface 23 slightly (minimally) at the 1 st corner 21 is determined and based on the center CP '.

The 2 nd corner 22 is a ridge portion (2 nd ridge portion) formed by the 2 nd wiring surface 10 and the wiring side surface 11 in the wiring portion 3. Specifically, the 2 nd corner portion 22 is formed across each of both end portions of the 2 nd wiring surface 10 in the 1 st direction and the other end portion in the thickness direction of the wiring side surface 11 continuous thereto. The 2 nd corner portion 22 is formed two per wiring portion 3.

The two 2 nd corner portions 22 are disposed on the other side in the thickness direction with respect to the two 1 st corner portions 21, respectively.

The 2 nd corner 22 is a 2 nd tip portion that tapers toward the 1 st direction outer side (the 1 st direction outer side is oblique and the 1 st direction other side). The 2 nd corner 22 has (is divided by) an inclined surface 24 and a flat surface 26.

The inclined surface 24 has a slope 27 as a main part. Preferably, the inclined surface 24 is formed by the sloping surface 27 only. The inclined surface 24 is continuous from a central portion (more specifically, a vicinity between the central portion and the other end portion) 50 in the thickness direction of the wiring side surface 11, and faces outward in the 1 st direction. The two inclined surfaces 24 corresponding to the two 2 nd corner portions 22 are arranged to face each other (to face each other) in the 1 st direction.

The slope 27 is inclined with respect to the thickness direction and the 1 st direction. That is, the slope surface 27 is inclined with respect to the thickness direction and the 1 st direction, and is along an inclined direction (the 1 st inclined direction) which is inclined outward in the 1 st direction as going to the other side in the thickness direction (refer to the directional arrow shown together with the enlarged view). The two slope surfaces 27 corresponding to the two inclined surfaces 24 are two slope surfaces (a partial example) in which the length between the two slope surfaces 27 increases as the distance approaches the other side in the thickness direction. Specifically, the slope 27 is inclined so as to extend outward in the 1 st direction and to expand in a terminal-expanded shape from the central portion (more specifically, the vicinity between the central portion and the other end portion) 50 in the thickness direction of the wiring side surface 11 toward both end edges (the 1 st insulating surface 7 of the 1 st insulating layer 2) in the 1 st direction of the 2 nd wiring surface 10. The slope 27 has a gradient (1 st direction length/thickness direction length) obtained by dividing the 1 st direction length by the thickness direction length, which is, for example, 0.001 or more, preferably 0.01 or more, more preferably 0.1 or more, and is, for example, 1.0 or less, preferably 0.75 or less.

The flat surface 26 is a flat surface extending straight from the other end edge of the inclined surface 24 on the other side in the thickness direction toward the 1 st direction inner side. The flat surfaces 26 correspond to both edges of the 2 nd wiring surface 10 in the 1 st direction. The flat surface 26 is in contact with the 1 st insulating surface 7.

The inclined surface 24 of the 2 nd corner portion 22 and the curved surface 23 of the 1 st corner portion 21 are disposed across, for example, a central portion 50 in the thickness direction of the wiring side surface 11.

The 2 nd corner 22 may have the same shape as the 2 nd tip portion 45 (see fig. 2A) of the wiring base 36, which will be described later.

The wiring side surface 11 continuously has a portion facing the outside in the 1 st direction in the curved surface 23 of the 1 st corner portion 21, the central portion 50 in the thickness direction, and a portion facing the outside in the 1 st direction in the inclined surface 24 of the curved surface 23.

The thickness direction center portions 50 of the two wiring side surfaces 11 each have a shape that is tapered inward in the 1 st direction. Specifically, the wiring side surfaces 11 have a shape (constricted portion) in which the length between them becomes the shortest at the center portion in the 1 st direction.

As shown by the virtual line in fig. 2B, the wiring portion 3 includes, for example, a wiring base portion 36 and plating layers 30 formed on one surface and both side surfaces in the thickness direction of the wiring portion 3.

Examples of the material of the wiring portion 3 include metals such as copper, nickel, gold, and solder, and conductors such as alloys of these metals, and copper is preferable.

The thickness of the wiring portion 3 is the length between the 1 st wiring surface 9 and the 2 nd wiring surface 10, and specifically, is, for example, 10 μm or more, preferably 30 μm or more, and is, for example, 500 μm or less, preferably 250 μm or less.

The width of the wiring portion 3 is, for example, 20 μm or more, preferably 50 μm or more, and is, for example, 2000 μm or less, preferably 1000 μm or less, as the distance between the edges in the 1 st direction of the two 1 st corner portions 21 opposed to each other.

The interval between the adjacent wiring portions 3 is, for example, 20 μm or more, preferably 50 μm or more, and is, for example, 1000 μm or less, preferably 500 μm or less, as the interval between the 1 st direction edges of the 1 st corner portions 21 adjacent to each other with the 2 nd insulating layer 4 (described later) and the magnetic layer 5 (described later) interposed therebetween.

The ratio of the thickness of the wiring portion 3 to the width of the wiring portion 3 (thickness/width) is, for example, 0.005 or more, preferably 0.03 or more, and, for example, 25 or less, preferably 5 or less. The ratio of the thickness of the wiring portion 3 to the interval between adjacent wiring portions 3 (thickness/interval) is, for example, 0.01 or more, preferably 0.06 or more, and is, for example, 25 or less, preferably 5 or less. The ratio (width/interval) of the width of the wiring portion 3 to the interval between adjacent wiring portions 3 is, for example, 0.02 or more, preferably 0.01 or more, and is, for example, 100 or less, preferably 20 or less.

The wiring portion 3 is provided on the wired circuit board preparation body 6 together with the insulating layer 1. That is, the wired circuit board preparation body 6 does not have the 2 nd insulating layer 4 and the magnetic layer 5 described below, but has the 1 st insulating layer 2 and the wiring portion 3. Preferably, the wired circuit board preparation body 6 is constituted only by the 1 st insulating layer 2 and the wiring portion 3.

The 2 nd insulating layer 4 is provided in plurality corresponding to the plurality of wiring portions 3. The 2 nd insulating layer 4 is formed in a film shape along the 1 st wiring surface 9 and the wiring side surface 11 (including the curved surface 23 and the inclined surface 24) of the wiring portion 3. The 2 nd insulating layer 4 has: a 4 th insulating surface 13 which is in contact with the 1 st wiring surface 9 and the wiring side surface 11; and a 3 rd insulating surface 12 disposed on one side in the thickness direction or on the outer side in the 1 st direction of the 4 th insulating surface 13 with a space from the 4 th insulating surface 13.

The 4 th insulating surface 13 has a shape corresponding to (specifically, the same as) the 1 st wiring surface 9 and the wiring side surface 11.

The 3 rd insulating surface 12 has a shape following the 4 th insulating surface 13 to secure the thickness T of the 2 nd insulating layer 4. The 3 rd insulating face 12 has a shape parallel to the 4 th insulating face 13.

The 2 nd insulating layer 4 is, for example, an electrodeposition layer (described later), a coating layer (described later), or the like, and is preferably an electrodeposition layer.

The 2 nd insulating layer 4 is relatively soft (particularly has a property of being softened in hot pressing in the 3 rd step (see fig. 2D) described later), for example, but does not have magnetism. Specifically, examples of the material of the 2 nd insulating layer 4 include a resin that does not contain the magnetic particles 18 (described in detail later in the magnetic layer 5). The resin of the 2 nd insulating layer 4 is preferably a resin having ionic property in water, and specifically, an acrylic resin, an epoxy resin, a polyimide resin, a mixture thereof, and the like are exemplified.

The thickness T of the second insulating layer 4 is relatively thin, and the average thickness thereof is, for example, 20 μm or less, preferably 15 μm or less, more preferably 10 μm or less, further preferably 7.5 μm or less, particularly preferably 5 μm or less, and most preferably 3 μm or less, and is, for example, 0.1 μm or more, preferably 0.5 μm or more, and more preferably 1 μm or more.

When the thickness T of the 2 nd insulating layer 4 is small and is equal to or less than the upper limit, the effective permeability of the magnetic layer 5 described below can be increased, and the inductance of the magnetic wired circuit board 1 can be increased.

On the other hand, when the 2 nd insulating layer 4 is too thin, magnetic particles in the magnetic layer 5 described later easily penetrate through the 2 nd insulating layer 4 and come into contact with the wiring portion 3.

However, in the magnetic wired circuit board 1, since the 1 st corner portion 21 of the wiring portion 3 has a substantially curved shape, the thickness T of the 2 nd insulating layer 4 can be suppressed from becoming too thin, the penetration of the 2 nd insulating layer 4 by the magnetic particles 18 can be suppressed, and the insulation of the 2 nd insulating layer 4 can be ensured.

The thickness T1 of the portion of the 2 nd insulating layer 4 covering the 1 st corner 21 is the same as the thickness T0 of the portion of the 2 nd insulating layer 4 covering the portion other than the 1 st corner 21 (for example, the thickness direction central portion 50 of the wiring side surface 11 and/or the 1 st direction central portion of the 1 st wiring surface 9), or the thickness T1 is allowed to be slightly smaller than the thickness T0.

In the 2 nd insulating layer 4, the ratio (T1/T0) of the thickness T1 of the portion covering the 1 st corner 21 to the thickness T0 of the portion covering the portion other than the 1 st corner 21 is, for example, 1 or less, preferably less than 1, more preferably 0.95 or less, further preferably 0.9 or less, and, for example, 0.7 or more, preferably 0.8 or more.

The thickness T1 of the portion of the 2 nd insulating layer 4 covering the 1 st corner 21 is, for example, 0.5 μm or more, preferably 1 μm or more, and is, for example, 10 μm or less, preferably 7 μm or less.

The thickness T0 of the portion of the 2 nd insulating layer 4 covering the other portion is, for example, 0.52 μm or more, preferably 1.04 μm or more, and is, for example, 14.49 μm or less, preferably 10.14 μm or less.

The average thickness of the 2 nd insulating layer 4 was calculated by assigning the above-described thickness T1 and thickness T0 to their area ratios.

The magnetic layer 5 is provided on the wired circuit board preparation body 6 in order to increase the inductance of the magnetic wired circuit board 1. The magnetic layer 5 has a shape extending in the planar direction.

The magnetic layer 5 embeds the wiring portion 3 with the insulating layer 2 interposed therebetween. Specifically, the magnetic layer 5 covers the 1 st wiring surface 9 and the wiring side surface 11 (including the curved surface 23 and the inclined surface 24) of the wiring portion 3 with the 2 nd insulating layer 4 interposed therebetween. In addition, the magnetic layer 5 covers an exposed surface 16 of the 1 st insulating surface 7 of the 1 st insulating layer 2 exposed from the 2 nd insulating layer 4.

The magnetic layer 5 has a 1 st magnetic surface 14 and a 2 nd magnetic surface 15.

The 1 st magnetic surface 14 is disposed on one side in the thickness direction with a space from the 3 rd insulating surface 12 of the 2 nd insulating layer 4. The 1 st magnetic surface 14 is exposed on one side in the thickness direction. The 1 st magnetic surface 14 has: a plurality of projections 28, the plurality of projections 28 projecting toward one side in the thickness direction in correspondence with the plurality of wiring portions 3; and a concave portion 29, the concave portion 29 being disposed between the convex portions 13 adjacent to each other, and sinking toward the other side in the thickness direction with respect to the convex portion 28.

The 2 nd magnetic surface 15 is disposed on the other side in the thickness direction of the 1 st magnetic surface 14 with a space from the 1 st magnetic surface 14.

The 2 nd magnetic face 15 is continuously in contact with the 3 rd insulating face 12 and the exposed face 16.

The magnetic layer 5 contains, for example, magnetic particles 18. Specifically, examples of the material of the magnetic layer 5 include a magnetic composition containing magnetic particles 18 having an aspect ratio of 2 or more and a resin component 19.

Examples of the magnetic material constituting the magnetic particles 18 include soft magnetic bodies and hard magnetic bodies. From the viewpoint of inductance, a soft magnetic body is preferably cited.

Examples of the soft magnetic material include a single metal material containing 1 metal element in a pure state, and an alloy material which is a eutectic (mixture) of 1 or more metal elements (1 st metal element) and 1 or more metal elements (2 nd metal element) and/or nonmetal elements (carbon, nitrogen, silicon, phosphorus, and the like). These materials can be used alone or in combination.

As the single metal body, for example, a simple metal body composed of only 1 kind of metal element (1 st metal element) can be cited. The 1 st metal element can be appropriately selected from, for example, iron (Fe), cobalt (Co), nickel (Ni), and metal elements that can be contained as the 1 st metal element of the soft magnetic material.

Examples of the single metal body include a core containing only 1 metal element and a surface layer containing an inorganic substance and/or an organic substance which modifies part or all of the surface of the core, and forms obtained by decomposing (thermally decomposing or the like) an organic metal compound containing the 1 st metal element and an inorganic metal compound. More specifically, the latter form includes iron powder (may be referred to as carbonyl iron powder) obtained by thermally decomposing an organic iron compound (specifically, carbonyl iron) containing iron as the 1 st metal element. The position of the layer including the inorganic substance and/or organic substance modified with the portion containing only 1 metal element is not limited to the surface described above. The organometallic compound and the inorganic metal compound that can obtain a single metal body are not particularly limited, and can be appropriately selected from known or conventional organometallic compounds and inorganic metal compounds that can obtain a single metal body of a soft magnetic body.

The alloy body is a eutectic of 1 or more metal elements (1 st metal element) and 1 or more metal elements (2 nd metal element) and/or nonmetal elements (carbon, nitrogen, silicon, phosphorus, and the like), and is not particularly limited as long as the alloy body can be used as a soft magnetic body.

The 1 st metal element is an essential element of the alloy body, and examples thereof include iron (Fe), cobalt (Co), nickel (Ni), and the like. In addition, if the 1 st metal element is Fe, the alloy body is an Fe-based alloy, if the 1 st metal element is Co, the alloy body is a Co-based alloy, and if the 1 st metal element is Ni, the alloy body is an Ni-based alloy.

The 2 nd metal element is an element (auxiliary component) which is contained In the alloy body In an auxiliary manner, and is a metal element which is compatible with (Co-melted with) the 1 st metal element, and examples thereof include iron (Fe) (In the case where the 1 st metal element is an element other than Fe), cobalt (Co) (In the case where the 1 st metal element is an element other than Co), nickel (Ni) (In the case where the 1 st metal element is an element other than Ni), chromium (Cr), aluminum (Al), silicon (Si), copper (Cu), silver (Ag), manganese (Mn), calcium (Ca), barium (Ba), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), molybdenum (Mo), tungsten (W), ruthenium (Ru), rhodium (Rh), zinc (Zn), gallium (Ga), indium (In), germanium (Ge), tin (Sn), lead (Pb), scandium (Sc), and the like, Yttrium (Y), strontium (Sr), various rare earth elements, etc. These elements can be used alone or in combination of two or more.

The nonmetal element is an element (auxiliary component) which is contained in the alloy body in an auxiliary manner, is compatible with (co-melted with) the 1 st metal element, and includes, for example, boron (B), carbon (C), nitrogen (N), silicon (Si), phosphorus (P), sulfur (S), and the like. These elements can be used alone or in combination of two or more.

Examples of Fe-based alloys as an alloy body include magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), sendust (Fe-Si-Al alloy) (including super sendust), permalloy (Fe-Ni alloy), Fe-Ni-Mo alloy, Fe-Ni-Mo-Cu alloy, Fe-Ni-Co alloy, Fe-Cr-Al alloy, Fe-Ni-Cr-Si alloy, copper-silicon alloy (Fe-Cu-Si alloy), Fe-Si alloy, Fe-Si-B (-Cu-Nb) alloy, Fe-B-Si-Cr alloy, Fe-Si-Cr-Ni alloy, Fe-Si-Cr-Si-Si alloy, Fe-Si-, Fe-Si-Cr alloy, Fe-Si-Al-Ni-Cr alloy, Fe-Ni-Si-Co alloy, Fe-N alloy, Fe-C alloy, Fe-B alloy, Fe-P alloy, ferrite (including stainless steel ferrite, and soft ferrite such as Mn-Mg ferrite, Mn-Zn ferrite, Ni-Zn-Cu ferrite, Cu-Zn ferrite, Cu-Mg-Zn ferrite), Permitron-Fe alloy (Fe-Co alloy), Fe-Co-V alloy, Fe-based amorphous alloy, etc.

Examples of the Co-based alloy as an alloy body include Co-Ta-Zr and a cobalt (Co) -based amorphous alloy.

Examples of the Ni-based alloy as an alloy body include Ni — Cr alloys and the like.

Among these soft magnetic materials, from the viewpoint of magnetic properties, an alloy body is preferably used, an Fe-based alloy is more preferably used, and sendust (Fe-Si-Al alloy) is further preferably used, and sendust having an Si content of 9 to 15 mass% is particularly preferably used from the viewpoint of obtaining a high magnetic permeability. In addition, the soft magnetic material preferably includes a single metal body, more preferably a single metal body containing an iron element in a pure state, and further preferably a simple iron substance or an iron powder (carbonyl iron powder).

Examples of the shape of the magnetic particles 18 include a flat shape (plate shape) having a small thickness and a large surface, and a shape having anisotropy such as a needle shape. In addition, isotropic magnetic particles can be contained. The isotropic magnetic particles may have a shape such as a sphere, a particle, a block, or a pellet. The shape of the magnetic particle 18 is preferably anisotropic.

When the magnetic particles 18 are flat, the aspect ratio of the magnetic particles is 2 or more, preferably 5 or more, more preferably 10 or more, and further preferably 20 or more, and the aspect ratio is 100 or less.

When the magnetic particles 18 are flat, the flatness ratio (flatness) is, for example, 8 or more, preferably 15 or more, and is, for example, 500 or less, preferably 450 or less. The aspect ratio is, for example, an aspect ratio obtained by dividing the average particle diameter (average length) of the magnetic particles 18 by the average thickness of the magnetic particles 18.

The content ratio of the magnetic particles 18 in the magnetic layer 5 (magnetic composition) is, for example, 50 v% or more, preferably 55 v% or more, and is, for example, 95 v% or less, preferably 90 v% or less.

Examples of the resin component 19 include thermosetting resins such as epoxy resin compositions containing epoxy resins, curing agents, and curing accelerators. Such a magnetic composition is described in, for example, japanese patent application laid-open nos. 2017 and 005115 and 2015 and 092543.

The thickness of the magnetic wired circuit board 1 is, for example, 30 μm or more, preferably 50 μm or more, and is, for example, 1000 μm or less, preferably 800 μm or less as the maximum thickness (thickness corresponding to the convex portion 28).

Next, a method for manufacturing the magnetic wired circuit board 1 will be described with reference to fig. 2A to 2D.

The manufacturing method includes a 1 st step (see fig. 2A and 2B) as an example of a step of preparing the 1 st insulating layer 2 and the wiring portion 3, a 2 nd step (see fig. 2C) of forming the 2 nd insulating layer 4, and a 3 rd step (see fig. 2D) as an example of a step of forming the magnetic layer 5.

As shown in fig. 2A and 2B, in the 1 st step, a wired circuit board preparation body 6 having the 1 st insulating layer 2 and the wiring portion 3 is prepared. The 1 st step includes a step of preparing the 1 st insulating layer 2 (see fig. 2A), a 4 th step of forming the wiring base 36 (see fig. 2A), and a 5 th step of forming the plating layer 30 (see fig. 2B).

In the 4 th step, the wiring base portion 36 is formed on the 1 st insulating surface 7 of the 1 st insulating layer 2 by a conductor patterning method such as a subtractive method or an additive method.

In forming the wiring base 36 by the subtractive method, first, a laminate (not shown) composed of the 1 st insulating layer 2 and a conductor layer (metal layer) is prepared, and then an etching resist is formed on one surface in the thickness direction of the conductor layer in the same pattern as the wiring base 36. Next, the conductor layer exposed from the etching resist is patterned by etching such as wet etching, dry etching, or the like, to form the wiring base portion 36. Preferably, the wiring base portion 36 is formed by wet etching. Then, the etching resist is removed by, for example, peeling off or the like.

In forming the wiring base 36 by the additive method, first, a conductor thin film (seed film) is formed on the 1 st insulating surface 7 of the 1 st insulating layer 2, and then a plating resist having a pattern opposite to that of the wiring base 36 is formed on one surface in the thickness direction of the conductor thin film. Next, the wiring base portion 36 is formed on the conductor film exposed from the plating resist by plating. Then, the plating resist and the conductor film corresponding thereto are removed.

As a conductor patterning method, a subtractive method is preferably cited. If the subtractive method is used, the wiring base portion 36 having a larger thickness can be formed more quickly than the additive method.

On the other hand, when the wiring base portion 36 is formed by the subtractive method, the 1 st tip portion 25 is formed on the wiring base portion 36, but as will be described later, the thinning of the 2 nd insulating layer 4 due to the 1 st tip portion 25 can be eliminated by the plating layer 30 formed in the 5 th step described later.

The wiring base 36 is a base (base) for forming the wiring portion 3, and forms the wiring portion 3 together with the plating layer 30 described later. That is, only the wiring base portion 36 shown in fig. 2A does not constitute the wiring portion 3.

The wiring base 36 has a 1 st tip portion 25 corresponding to the 1 st corner portion 21, a base center side surface 51 corresponding to the thickness direction center portion 50, and a 2 nd tip portion 45 corresponding to the 2 nd corner portion 22.

The 1 st tip portion 25 is a ridge line portion formed by one surface and side surfaces in the thickness direction of the wiring base portion 36. The 1 st tip portion 25 is inclined toward the 1 st direction outer side and sharply pointed on the 1 st direction side. The angle β 1 of the 1 st tip portion 25 (the angle formed by the 1 st wiring surface 9 and the end portion of the wiring side surface 11) is, for example, 135 degrees or less, preferably 120 degrees or less, more preferably 90 degrees or less, and is, for example, 30 degrees or more, preferably 45 degrees or more.

The 2 nd tip portion 45 is a ridge line portion formed by the other surface and the side surface in the thickness direction of the wiring base portion 36. The 2 nd tip portion 45 is inclined toward the 1 st direction outer side and sharply pointed at the 1 st direction other side. The angle β 2 of the 2 nd tip portion 45 (the angle formed by the 2 nd wiring surface 10 and the end portion of the wiring side surface 11) is, for example, 35 degrees or more, preferably 45 degrees or more, more preferably more than 80 degrees, and is, for example, 150 degrees or less, preferably 135 degrees or less.

The base central side 51 is a joining surface joining the 1 st tip portion 25 and the 2 nd tip portion 45 together in the thickness direction.

The material of the wiring base portion 36 is the same as that of the wiring portion 3 described above.

Then, in the 5 th step, as shown in fig. 2B, the plating layer 30 is formed on the wiring base 36.

The material of the plating layer 30 can be selected as appropriate from the materials of the wiring base 36, and is preferably the same as the material of the wiring base 36.

The plating layer 30 is formed by plating.

Examples of the plating include electroplating and electroless plating. From the viewpoint of forming the plating layer 30 thick, electroplating (more preferably electrolytic copper plating) is preferably used.

The plating layer 30 is laminated on one surface and both side surfaces in the thickness direction of the wiring base 36 by plating. In the plating, the plating layer 30 is formed in a precipitated state on one surface and both side surfaces in the thickness direction of the wiring base 36.

By this plating, the 1 st covering portion 31 as an example of the covering portion grown (plating growth) toward the thickness direction side and the 1 st direction outside is deposited on the 1 st tip portion 25. The 1 st covering part 31 forms a 1 st corner 21 having a curved surface 23.

On the other hand, in the wiring base 36, the 2 nd covering part 32 grown (plating growth) toward the thickness direction side or the 1 st direction outside is deposited in a portion other than the 1 st tip part 25 (a portion including the 2 nd tip part 45 and the thickness direction central part 50). The 2 nd covering part 32 forms one surface and both side surfaces in the thickness direction of the wiring base 36 (here, a portion excluding the 1 st corner part 21, and a portion including the thickness direction central part 50 and the inclined surface 24).

That is, the plating layer 30 has a 1 st covering part 31 and a 2 nd covering part 32. Preferably, the plating layer 30 is constituted only by the 1 st covering part 31 and the 2 nd covering part 32.

The 1 st covering part 31 is formed by plating growth of a plating component from the 1 st tip part 25 in a substantially radial shape (a fan shape in a direction excluding the inside of the 1 st tip part 25) in cross section. Therefore, the 1 st covering part 31 has the curved surface 23.

On the other hand, with the 2 nd covering portion 32, the plating component grows from each surface in a direction orthogonal to each surface at a portion other than the 1 st tip portion 25, specifically, the plating component grows by planar plating toward the upper side in the thickness direction at one surface in the thickness direction of the wiring base portion 36, and the plating component grows by planar plating toward both outer sides in the 1 st direction in both side surfaces (including the side surfaces of the 2 nd tip portion 45) of the wiring base portion 36. Therefore, the 2 nd covering portion 32 does not have the curved surface 23 described above, but has the 1 st wiring surface 9 and the wiring side surface 11 (including the thickness direction central portion 50, but excluding the curved surface 23).

The 2 nd covering part 32 includes the 2 nd corner part 22, and the 2 nd corner part 22 includes the inclined surface 24 based on the plating growth.

In the plating layer 30, the thickness (growth thickness or plating thickness) of the 1 st covering portion 31 is preferably thicker than the thickness (growth thickness or plating thickness) of the 2 nd covering portion 32. If the plating is electroplating, the current density of the 1 st tip portion 25 is higher than that of the portion other than the 1 st tip portion 25 in the wiring base portion 36. Therefore, the plating growth of the 1 st covering part 31 is faster than that of the 2 nd covering part 32, and therefore, the thickness of the 1 st covering part 31 is thicker than that of the 2 nd covering part 32.

The thickness of the plating layer 30 is appropriately set according to the growth rate of plating and the plating time. The growth rate and plating time of the plating are appropriately set according to, for example, the metal (conductor) concentration, temperature, and the like in the plating solution used for the plating, for example, the current density, the inter-electrode distance, the degree of stirring (speed) in the bath, the copper sulfate concentration, the sulfuric acid concentration, the chloride ion concentration, and the type and amount of additives (leveler, brightener, polymer) in the case of the plating being electroplating, for example, the type and amount of the catalyst adhering to the surface of the wiring base 36 in the case of the plating being electroless plating.

As shown in fig. 2B, a boundary indicated by a virtual line is shown between the wiring base 36 and the plating layer 30, but if the material of the plating layer 30 is the same as that of the wiring base 36, the boundary is unclear or nonexistent (invisible).

In this plated layer 30, the 1 st covering portion 31 is formed by the above-described plating, and therefore has the above-described curved surface 23. On the other hand, the 2 nd covering portion 32 has the inclined surface 24.

Next, in the 2 nd step, as shown in fig. 2C, the 2 nd insulating layer 4 is formed on the wired circuit board preparation body 6. Specifically, the 1 st wiring surface 9 and the wiring side surface 11 of the wiring portion 3 are covered with the 2 nd insulating layer 4.

Examples of a method for forming the 2 nd insulating layer 4 include electrodeposition (electrodeposition coating), coating such as printing, and the like.

In the electrodeposition, the wired circuit board preparation body 6 (the magnetic wired circuit board 1 in the manufacturing process) is immersed in an electrodeposition liquid containing a resin (preferably, an electrodeposition paint), and then, a current is applied to the wiring portion 3, so that a coating of the resin is deposited on the 1 st wiring surface 9 and the wiring side surface 11 of the wiring portion 3. Then, the coating film is dried as necessary. Thereby, the 2 nd insulating layer 4 is formed as an electrodeposition layer. Then, the 2 nd insulating layer 4 (electrodeposition layer) is heated and cured by sintering as necessary.

In printing as an example of the application, a varnish containing a resin is applied to the 1 st wiring surface 9 and the wiring side surface 11 of the wiring portion 3 via a screen (screen printing). Then, the coating film is dried.

As a method of forming the 2 nd insulating layer 4, electrodeposition is preferably cited. If electrodeposition is employed, the thickness T of the 2 nd insulating layer 4 can be made thin (however, the thickness is set to a thickness that can ensure the insulation of the 2 nd insulating layer 4). Further, since the exposure surface 16 can be reliably exposed by the 2 nd insulating layer 4 by electrodeposition, the magnetic layer 5 can be disposed across the entire thickness direction between the adjacent wiring portions 3 in the next 3 rd step, and therefore the effective permeability of the magnetic layer 5 can be increased, and the inductance of the magnetic wired circuit board 1 can be increased.

Then, in the 3 rd step, as shown in fig. 2D, the magnetic layer 5 is formed on the wired circuit board preparation body 6. Specifically, the 1 st wiring surface 9 and the wiring side surface 11 of the wiring portion 3 are covered with the magnetic layer 5 via the 2 nd insulating layer 4.

In the 3 rd step, for example, as shown in fig. 2C, first, the magnetic sheet 17 as an example of the particle-containing sheet is prepared. In order to prepare the magnetic sheet 17, for example, a magnetic composition containing the above-described magnetic particles and a resin component (preferably, a B-stage thermosetting resin) is formed into a sheet shape. In the magnetic sheet 17, the magnetic particles 18 are oriented (aligned) in the surface direction (direction orthogonal to the thickness direction) of the magnetic sheet 17.

Then, as shown by the arrow in fig. 2C, the magnetic sheet 17 is thermally pressed against the 2 nd insulating layer 4 of the wired circuit board preparation body 6. The magnetic sheet 17 is disposed on one side in the thickness direction of the wired circuit board preparation body 6, and the magnetic sheet 17 is hot-pressed against one side in the thickness direction of the wired circuit board preparation body 6.

Thus, the magnetic sheet 17 embeds the wiring portion 3 through the 2 nd insulating layer 4. Specifically, the magnetic sheet 17 covers the 1 st wiring surface 9 of the 2 nd insulating layer 4 with the 2 nd insulating layer 4 interposed therebetween, and enters (sinks) between the wiring portions 3 adjacent to each other (the portions facing the exposed surfaces 16), and fills (partially) between the wiring portions 3 adjacent to each other.

In the magnetic sheet 17 before and after the hot pressing, the orientation direction (specifically, the plane direction) of the magnetic particles 18 facing the 1 st wiring surface 9 of the wiring portion 3 does not change. In the magnetic sheet 17 before and after the hot pressing, the orientation direction (specifically, the surface direction) of the magnetic particles 18 facing the exposed surface 16 does not change.

On the other hand, in the magnetic sheet 17 before and after hot pressing, the orientation direction (specifically, the plane direction) of the magnetic particles 18 facing the 1 st corner 21 is a direction along the curved surface 23 (i.e., an oblique direction inclined outward in the 1 st direction as going to the other side in the thickness direction). That is, the magnetic particles 18 are oriented along the curved surface 23.

In the magnetic sheet 17 before and after the hot pressing, the orientation direction (specifically, the plane direction) of the magnetic particles 18 facing the 2 nd corner 22 is a direction along the inclined surface 24 (i.e., an oblique direction inclined outward in the 1 st direction as going toward the other side in the thickness direction). That is, the magnetic particles 18 are oriented along the inclined surface 24.

On the other hand, in the magnetic sheet 17 before and after the hot pressing, the orientation direction (specifically, the plane direction) of the magnetic particles 18 facing the portion of the wiring side surface 11 between the 1 st corner portion 21 and the 2 nd corner portion 22 becomes a direction along the thickness direction. That is, the magnetic particles 18 described above are oriented in the thickness direction.

Thus, the magnetic sheet 17 covers the wiring portion 3 with the insulating layer 4 of the 2 nd layer interposed therebetween, and forms (molds) the magnetic layer 5 having the convex portion 28 and the concave portion 29.

The magnetic particles 18 oriented in the magnetic layer 5 as described above form a smooth magnetic path around the wiring portion 3.

Thus, the magnetic wired circuit board 1 having the wired circuit board preparation body 6 and the magnetic layer 5 was obtained. The magnetic wired circuit board 1 is preferably constituted only by the wired circuit board preparation body 6 and the magnetic layer 5.

Then, when the magnetic layer 5 contains a B-stage thermosetting resin, the magnetic layer 5 is C-staged (completely cured) by, for example, heating, as necessary.

The magnetic wired circuit board 1 is applied to, for example, wireless power transmission (wireless power supply and/or wireless power reception), wireless communication, a sensor, a driven part, and the like.

In the magnetic wired circuit board 1, the 1 st corner portion 21 of the wiring portion 3 (a portion corresponding to the substantially curved shape in the wiring portion 3) has a substantially curved shape, and therefore, the 2 nd insulating layer 4 can be formed while suppressing the 2 nd insulating layer 4 covering such 1 st corner portion 21 from becoming excessively thin. Therefore, the magnetic particles 18 can be prevented from penetrating the 2 nd insulating layer 4 and coming into contact with the wiring portion 3. As a result, the insulating property of the magnetic layer 5 with respect to the wiring portion 3 can be secured by the 2 nd insulating layer 4.

In addition, in the magnetic layer 5 covering the 1 st corner 21 through the 2 nd insulating layer 4, the magnetic particles 18 can be oriented along the curved shape of the 1 st corner 21. That is, the magnetic particles 18 are oriented in the surface direction in the magnetic layer 5 facing the 1 st wiring surface 9 of the wiring portion 3, in the thickness direction in the magnetic layer 5 facing the wiring side surface 11 of the wiring portion 3, and in the direction inclined with respect to the thickness direction and the 1 st direction in the magnetic layer 5 facing the 1 st corner portion 21. Therefore, a smooth magnetic path can be formed in the magnetic layer 5 around the wiring portion 3. Therefore, the effective permeability around the wiring portion 3 can be improved. As a result, the magnetic wired circuit board 1 has high inductance.

Therefore, the magnetic wired circuit board 1 has high inductance and the insulating property of the 2 nd insulating layer 4 is excellent.

In the magnetic wired circuit board 1, if the 2 nd insulating layer 4 is an electrodeposition layer, the thickness of the 2 nd insulating layer 4 can be made thin. Therefore, a decrease in the effective permeability of the magnetic layer 5 covering the wiring portion 3 with the 2 nd insulating layer 4 interposed therebetween can be suppressed. As a result, the magnetic wired circuit board 1 has high inductance.

On the other hand, when the thickness of the 2 nd insulating layer 4, specifically, the thickness T1 of the 2 nd insulating layer 4 facing the 1 st tip 25 is small as shown in fig. 9A, the magnetic particles 18 easily penetrate through the thin 2 nd insulating layer 4 and come into contact with the wiring portion 3 as shown in fig. 9B. However, in the magnetic wired circuit board 1, as shown in fig. 1, the 1 st corner portion 21 of the wiring portion 3 has a substantially curved shape, and the 2 nd insulating layer 4 covering such 1 st corner portion 21 can be prevented from being formed with an excessively thin thickness, so that the magnetic particles 18 can be prevented from penetrating the 2 nd insulating layer 4, and the insulating property of the 2 nd insulating layer 4 can be ensured.

In the magnetic wired circuit board 1, since the curved surface 23 is gentle if the radius of curvature R of the 1 st corner portion 21 is large and 9 μm or more, the 2 nd insulating layer 4 corresponding to the 1 st corner portion 21 can be formed with a sufficient thickness T1. In addition, in the 2 nd insulating layer 4 facing the 1 st corner 21, the magnetic particles 18 can be reliably oriented along the curved surface 23.

When the average thickness T of the 2 nd insulating layer 4 is small and 10 μm or less, a decrease in the effective permeability of the magnetic layer 4 can be suppressed. As a result, the magnetic wired circuit board 1 has high inductance.

In addition, in the magnetic wired circuit board 1, since the magnetic layer 5 covers the exposed surface 16, the magnetic particles 18 in such a magnetic layer 5 can be oriented in the plane direction.

Further, since the 2 nd corner 22 formed by the 2 nd wiring surface 10 and the wiring side surface 11 of the wiring portion 3 has the slope 27 in which the length between the two wiring side surfaces 11 facing each other becomes longer as the 2 nd wiring surface 10 comes closer, the magnetic particles 18 can be aligned in the direction inclined with respect to the 1 st direction in correspondence with the slope 27 in the magnetic layer 5 covered with the 2 nd insulating layer 4.

Therefore, a smooth magnetic path can be formed around the 2 nd corner portion 22. Therefore, the magnetic wired circuit board 1 has a higher inductance.

However, as shown in fig. 9A and 9B, when the magnetic sheet 17 is thermally pressed against the 2 nd insulating layer 4 in the 2 nd step, the magnetic particles 18 contained in the magnetic sheet 17 easily penetrate through the 2 nd insulating layer 4 and come into contact with the wiring portion 3.

However, in the method of manufacturing the magnetic wired circuit board 1, since the 1 st corner portion 21 having a substantially curved shape is formed in the wiring portion 3 in the 1 st step as shown in fig. 2B, the 2 nd insulating layer 4 covering such 1 st corner portion 21 can be formed thick as shown in fig. 2C.

Therefore, the magnetic particles 18 can be suppressed from penetrating the 2 nd insulating layer 4 and the magnetic particles 18 can be suppressed from contacting the wiring.

Therefore, this manufacturing method can obtain the magnetic wired circuit board 1 having excellent insulation of the 2 nd insulating layer 4.

In addition, in the 2 nd step, since the magnetic sheet 17 containing the magnetic particles 18 oriented in the plane direction is thermally pressed against the 2 nd insulating layer 4, the magnetic particles 18 can be oriented along the curved shape of the 1 st corner 21 in the magnetic layer 5 covering the 1 st corner 21 with the 2 nd insulating layer 4 interposed therebetween. That is, the magnetic particles 18 can be oriented in the surface direction in the magnetic layer 5 facing the 1 st wiring surface 9 of the wiring portion 3, the magnetic particles 18 can be oriented in the thickness direction in the magnetic layer 5 facing the wiring side surface 11 of the wiring portion 3, and the magnetic particles 18 can be oriented in the direction inclined with respect to the thickness direction and the 1 st direction in the magnetic layer 5 facing the 1 st corner portion 21. Therefore, a smooth magnetic path can be formed in the magnetic layer 5 around the wiring portion 3. Therefore, the effective permeability around the wiring portion 3 can be improved. As a result, the magnetic wired circuit board 1 having a high inductance can be manufactured.

Therefore, this manufacturing method can obtain the magnetic wired circuit board 1 having high inductance and excellent insulation of the 2 nd insulating layer 4.

However, as shown in fig. 2A, when the wiring portion 3 having the tip portion is formed in the 1 st step, as shown in fig. 9A, the thickness T1 of the 2 nd insulating layer 4 opposed to the 1 st tip portion 25 easily becomes excessively thin in the 2 nd step. Then, as shown in fig. 9B, in the 3 rd step, when the magnetic layer 5 is formed, the magnetic particles 18 come into contact with the wiring portion 3, and therefore, insulation between the magnetic layer 5 and the wiring portion 3 cannot be secured.

However, as shown in fig. 2A, even if the wiring base 36 having the 1 st tip portion 25 is formed in the 4 th step, the 1 st corner portion 21 is formed in a substantially curved shape by the 1 st covering portion 31 by forming the plating layer 30 having the 1 st covering portion 31 covering the 1 st tip portion 25 in the 5 th step as shown in fig. 2B. Therefore, as shown in fig. 2C, in the 2 nd step, the 2 nd insulating layer 4 can be formed while suppressing the 2 nd insulating layer 4 covering the 1 st corner 21 from becoming too thin, that is, the 2 nd insulating layer 4 can be formed to have a thickness T1 (see the enlarged view of fig. 1).

As shown in fig. 2D, by forming the magnetic layer 5 in the 3 rd step, the magnetic particles 18 in the magnetic layer 5 can be prevented from penetrating the 2 nd insulating layer 4 and coming into contact with the wiring portion 3.

< modification example >

In the following modifications, the same members and steps as those of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Each modification can achieve the same operational effects as those of the first embodiment except for the contents specifically described. Further, one embodiment and its modifications can be combined as appropriate.

In one embodiment, a magnetic wired circuit board 1 having a magnetic layer 5 is described as an example of the wired circuit board of the present invention. However, the present invention is not limited to this, and a wired circuit board having a particle-containing layer other than the magnetic layer 5 may be used.

The particle-containing layer contains conductive particles other than the magnetic particles described above at an appropriate ratio. The conductive particles are not particularly limited, and examples thereof include metal particles such as copper particles, silver particles, gold particles, iron particles, and solder particles.

In order to obtain a wired circuit board having a particle-containing layer, referring to fig. 2C, the particle-containing sheet described above is prepared in place of the magnetic sheet 17, and the particle-containing sheet is hot-pressed against the wired circuit board preparation body 6.

In this wired circuit board, since the 1 st corner portion 21 of the wiring portion 3 has a substantially curved shape, the 2 nd insulating layer 4 can be formed while suppressing the 2 nd insulating layer 4 covering such 1 st corner portion 21 from becoming too thin. Therefore, the conductive particles can be prevented from penetrating the 2 nd insulating layer 4 and coming into contact with the wiring portion 3. As a result, the insulating property of the particle-containing layer with respect to the wiring portion 3 can be ensured by the 2 nd insulating layer 4.

However, in the 2 nd step, when the particle-containing sheet is thermally pressed against the 2 nd insulating layer 4, the conductive particles contained in the particle-containing sheet easily penetrate through the 2 nd insulating layer 4 and come into contact with the wiring.

However, in this method for manufacturing a wired circuit board, since the 1 st corner portion 21 having a substantially curved shape is formed in the wiring portion 3 in the 1 st step, the 2 nd insulating layer 4 covering such 1 st corner portion 21 can be formed thick.

Therefore, it is possible to suppress the conductive particles from penetrating the 2 nd insulating layer 4 and from coming into contact with the wiring portion 3.

Therefore, this manufacturing method can obtain a wired circuit board that ensures insulation of the 2 nd insulating layer 4.

Therefore, the wired circuit board can ensure insulation of the 2 nd insulating layer 4.

As shown in fig. 1, in one embodiment, 1 wiring portion 3 has a constricted portion in which the length between two wiring side surfaces 11 becomes the shortest at the center portion in the 1 st direction. However, as shown in fig. 4, the wiring portion 3 may have a wiring side surface 11 without a constricted portion.

Fig. 1 in one embodiment shows an example in which the plating layer 30 is relatively thick. As shown in fig. 4, this modification is an example in which the thickness of the plating layer 30 is smaller than that of the plating layer 30 of the embodiment.

In this modification, the radius of curvature R of the circle C forming the curved surface 23 is small, and the central angle α is also small. The radius of curvature R is, for example, less than 9 μm, even less than 5 μm, even less than 2 μm, and the central angle α is less than 110 degrees.

The curvature radius R of this modification is smaller than that of the first embodiment, but the 2 nd insulating layer 4 corresponding to the curved surface 23 can be formed with a sufficient thickness as in the first embodiment.

In addition, as shown in fig. 1, in one embodiment, the 2 nd corner 22 has an inclined surface 24, and the inclined surface 24 has a slope 27. However, as shown in fig. 5, the 2 nd corner portion 22 may have a vertical surface 33 formed perpendicularly to the flat surface 26 instead of the inclined surface 24.

The length between the two perpendicular surfaces 33 opposed to each other is the same toward the other side in the thickness direction.

As shown in fig. 6, the inclined surface 24 may have a 2 nd slope (1 st narrowing surface) 34 narrowing inward in the 1 st direction (japanese: すぼむ) as it goes toward the 1 st insulating surface 7, instead of the slope 27 spreading outward in the 1 st direction as it goes toward the 2 nd wiring surface 10.

Such a 2 nd slope surface (1 st narrowing surface) 34 is formed by, for example, an additive method.

As shown in fig. 1, in one embodiment, the inclined surface 24 is formed by only the slope surface 27. However, as shown in fig. 7, for example, the other end edge in the thickness direction of the inclined surface 24 may be the 2 nd curved surface 35. The 2 nd curved surfaces 35 adjacent to each other are 2 nd narrowing surfaces 37 whose length becomes shorter toward the 1 st insulating surface 7. In this case, the wiring side surface 11 has a portion facing the outside in the 1 st direction in the curved surface 23 of the 1 st corner portion 21, the thickness direction central portion 50, and the slope 27 and the 2 nd narrowing surface 37 in the inclined surface 24 in succession.

In one embodiment, as shown in fig. 1A to 1B, the wiring portion 3 includes flat surfaces (for example, the 1 st wiring surface 9 and the 2 nd wiring surface 10), but in this modification, as shown in fig. 8C, the wiring portion 3 does not include a flat surface and has a substantially circular cross section.

More specifically, the wiring portion 3 has a substantially circular shape when cut in a cross section perpendicular to the direction in which current flows (the direction of conveyance) (the depth direction of the paper). The wiring portion 3 has a wiring peripheral surface 46 as an outer peripheral surface.

The radius of the wiring portion 3 is, for example, 25 μm or more, preferably 50 μm or more, and is, for example, 2000 μm or less, preferably 200 μm or less.

The 2 nd insulating layer 4 covers the wiring peripheral surface 37 of the wiring portion 3. The 2 nd insulating layer 4 is formed with a uniform thickness along the 1 st peripheral surface 37, and specifically, the 2 nd insulating layer 4 has a substantially annular shape in cross section. The 2 nd insulating layer 4 has an inner peripheral surface in contact with the wiring peripheral surface 46 of the wiring portion 3 and an insulating peripheral surface 47 as an outer peripheral surface. The other end edge in the thickness direction of the insulating peripheral surface 47 is in contact with the 1 st insulating surface 7 of the 1 st insulating layer 2.

The thickness T of the 2 nd insulating layer 4 is a distance between the inner peripheral surface and the insulating peripheral surface 47, as disclosed in one embodiment.

The magnetic layer 5 covers the wiring peripheral surface 46 of the wiring portion 3 with the insulating layer 4 of the 2 nd layer interposed therebetween.

In the magnetic layer 5, the magnetic particles 18 are oriented along the wiring peripheral surface 46 of the wiring portion 3, specifically, along the insulating peripheral surface 47 of the 2 nd insulating layer 4 in the vicinity of the 2 nd insulating layer 4. The vicinity of the 2 nd insulating layer 4 is defined as, for example, a region within 1.5 times the radius of the wiring portion 3.

As shown in fig. 8A, to manufacture the magnetic wired circuit board 1, first, the 1 st insulating layer 2 is prepared. In addition, the wiring portion 3 and the 2 nd insulating layer 4 are prepared. A commercially available enamel wire can be prepared for the wiring portion 3 and the 2 nd insulating layer 4.

Next, as shown in fig. 8B, the other end edge in the thickness direction of the 2 nd insulating layer 4 is disposed on the 1 st insulating surface 7 of the 1 st insulating layer 2. Thereby, the 1 st step and the 2 nd step are performed simultaneously.

Then, the magnetic sheet 17 is thermally pressed against the 1 st insulating layer 2, the wiring portion 3, and the 2 nd insulating layer 4 (step 3).

Thereby, in the 2 nd insulating layer 4, in the vicinity of the 2 nd insulating layer 4, the magnetic particles 18 are oriented along the wiring peripheral surface 46 of the wiring portion 3, specifically, along the insulating peripheral surface 47 of the 2 nd insulating layer 4.

Thus, the magnetic wired circuit board 1 having the 1 st insulating layer 2, the wiring portion 3, the 2 nd insulating layer 4, and the magnetic layer 5 was obtained.

In the magnetic wired circuit board 1, the magnetic particles 18 can form a smooth magnetic path along the wiring peripheral surface 46, specifically, along the insulating peripheral surface 47 in the magnetic layer 5 around (in the vicinity of) the wiring portion 3 (the 2 nd insulating layer 4). Therefore, the effective permeability around the wiring portion 3 can be improved. As a result, the magnetic wired circuit board 1 has high inductance.

In the method of manufacturing the magnetic wired circuit board 1, in the 3 rd step, the magnetic particles 18 can form a smooth magnetic path along the substantially curved shape of the wiring portion 3 in the magnetic layer 5 around (in the vicinity of) the wiring portion 3 (the 2 nd insulating layer 4). Therefore, the effective permeability around the wiring portion 3 can be improved. As a result, the magnetic wired circuit board 1 having a high inductance can be manufactured.

The proportion of the magnetic particles 18 in the magnetic layer 5 may be the same in the magnetic layer 5, or may be higher or lower as the distance from each wiring portion 3 increases.

In the modification shown in fig. 8A to 8C, the wiring portion 3 has a substantially circular cross section, but is not particularly limited as long as it has a substantially curved shape in cross section, and may be, for example, a substantially rectangular or substantially trapezoidal shape having at least 1 corner portion of the substantially curved shape, although this case is not shown. In this modification, the insulating layer 4 covers the entire wiring peripheral surface 46 of the wiring portion 3, but this case is not illustrated.

The present invention is provided as an exemplary embodiment of the present invention, but this is merely an example and cannot be interpreted as a limitation. Modifications of the present invention that are obvious to those skilled in the art are intended to be covered by the following claims.

Industrial applicability

The wired circuit board is used for magnetic applications.

Description of the reference numerals

1. A magnetic wired circuit board (an example of a wired circuit board); 2. 1 st insulating layer; 3. a wiring portion (an example of wiring); 4. a 2 nd insulating layer; 5. a magnetic layer (an example of a particle-containing layer); 7. 1 st insulating surface; 9. 1 st wiring surface; 10. a 2 nd wiring surface; 11. a wiring side; 16. an exposed surface; 17. magnetic flakes (particles containing one example of flakes); 18. magnetic particles; 21. the 1 st corner; 22. a 2 nd corner portion; 24. an inclined surface; 25. a tip portion; 27. a slope surface; 30. plating; 31. a 1 st covering part; 36. a wiring base; 46. a wiring peripheral surface; 47. an insulating peripheral surface; t, thickness of the 2 nd insulating layer (average thickness).