TW201941669A - Wiring circuit board and method for manufacturing same - Google Patents

Abstract

This wiring circuit board is provided with: a first insulation layer; a wiring disposed on one surface, in the thickness direction, of the first insulation layer; a second insulation layer which covers the wiring; and a particle-containing layer which contains electrically conductive particles each having a shape, the aspect ratio of which is 2 or more, and which covers the wiring via the second insulation layer. The wiring has a substantially curved shape.

Description

Wiring circuit board and manufacturing method thereof

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

Previously, it has been known that coil modules can be used in wireless communication or wireless power transmission that transmits power wirelessly.

For example, there is proposed a coil module including a coil pattern and a magnetic layer in which the coil pattern is buried and contains flat-shaped magnetic particles (conductive particles) (for example, refer to Patent Document 1).

Such a coil module is obtained, for example, by first forming a coil pattern using a conductor pattern, and then heat-pressing a magnetic sheet containing magnetic particles with respect to the coil pattern.
[Prior technical literature]
[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2017-005115

[Problems to be solved by the invention]

However, there may be a case where a large current flows in the coil pattern. In this case, the flat-shaped magnetic particles contained in the insulating layer may cause a short circuit between the coil patterns. Therefore, insulation between the coil pattern and the magnetic layer is required.

Therefore, it is attempted to form an insulating layer between the coil pattern and the magnetic layer.

However, since the ridgeline portions on the upper surface and the side surface of the coil pattern are formed with sloping side (outside) spurs that are inclined upward, in this case, if an insulating layer is formed, the spurs face the spurs. The thickness of the insulating layer easily becomes too thin. Therefore, if a magnetic sheet containing magnetic particles is thermally pressed with respect to a coil pattern including a sharp portion through an insulating layer, the magnetic particles penetrate the insulating layer facing the sharp portion and come into contact with the sharp portion, As a result, there is a problem that the insulation between the magnetic layer and the coil pattern cannot be ensured due to the contact.

On the other hand, the coil module is also required to have a higher inductance.

The invention provides a wiring circuit substrate capable of ensuring the insulation property of a particle-containing layer to wiring and having a high inductance, and a manufacturing method thereof.
[Technical means to solve the problem]

The present invention (1) includes a wiring circuit board including: a first insulating layer; wiring arranged on one side in the thickness direction of the first insulating layer; a second insulating layer covering the wiring; and a particle-containing layer, which It contains conductive particles having a shape having an aspect ratio of 2 or more, and covers the wiring via the second insulating layer; and the wiring has a substantially curved shape.

In this wiring circuit board, since the wiring has a substantially curved shape, a second insulating layer covering a portion of the wiring corresponding to the substantially curved shape can be formed so as to prevent the second insulating layer from becoming too thin. Therefore, it is possible to prevent the conductive particles from penetrating the second insulating layer and coming into contact with the wiring. As a result, the second insulating layer can ensure the insulation of the particle-containing layer from the wiring.

Therefore, this printed circuit board can ensure the insulation of the second insulating layer.

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

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

Therefore, the wiring circuit board can have a high inductance and can ensure the insulation of the second insulating layer.

The present invention (3) includes the wiring circuit board according to (2), wherein the second insulating layer is an electrodeposited layer.

In this wiring circuit board, the second insulating layer is an electrodeposited layer, so that the thickness of the second insulating layer can be made thin. Therefore, it is possible to suppress a decrease in the effective magnetic permeability of the magnetic layer covering the wiring via the second insulating layer. As a result, the wiring circuit board has a high inductance.

On the other hand, when the thickness of the second insulating layer is thin, the magnetic particles easily penetrate the thin second insulating layer and come into contact with the wiring. However, in this wiring circuit board, in the second insulating layer covering the wiring having a substantially curved shape, the thickness is prevented from being too thin, so that the penetration of the magnetic particles into the second insulating layer can be suppressed, thereby ensuring the second insulation Layer of insulation.

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

In this printed circuit board, since the average thickness T of the second insulating layer is as thin as 10 μm or less, the effective magnetic permeability of the magnetic layer can be suppressed from decreasing. As a result, the wiring circuit board has a high inductance.

The present invention (5) includes the wiring circuit board according to any one of (2) to (4), wherein the wiring has a thickness direction surface spaced apart from the thickness direction surface of the first insulating layer. Opposite arrangement; the other side in the thickness direction, which is in contact with the one side in the thickness direction of the first insulating layer; and the side, which connects the two ends of the one surface in the thickness direction and the other side in the thickness direction; the second insulating layer is covered In the one surface in the thickness direction and the side surface, the wiring has a corner portion formed by the one surface in the thickness direction and the side surface, and the corner portion has a substantially curved shape.

In this wiring circuit board, the corners of the wiring have a substantially curved shape, so that the second insulating layer covering the corners can be formed so as to prevent the second insulating layer from becoming too thin. Therefore, it is possible to prevent the conductive particles from penetrating the second insulating layer and coming into contact with the corners of the wiring. As a result, the second insulating layer can ensure the insulation of the particle-containing layer from the wiring. Therefore, this printed circuit board can ensure the insulation of the second insulating layer.

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

In this printed circuit board, if the radius of curvature R of the corner portion is as high as 9 μm or more, the arc surface of the corner portion is relatively gentle, so that a second insulating layer corresponding to the corner portion can be formed with a sufficient thickness. In the second magnetic layer facing the corner, the magnetic particles can be aligned along the arc surface of the corner.

The present invention (7) includes the wiring circuit board according to (5) or (6), in which the magnetic layer covers the thickness direction surface exposed from the second insulating layer in the first insulating layer, and the wiring has A second corner portion formed by the other surface in the thickness direction and the side surface, and the second corner portion has a portion in which the length between the two side surfaces facing each other becomes longer as the second corner portion approaches the other side in the thickness direction.

In this printed circuit board, the magnetic layer covers one surface of the first insulating layer in the thickness direction exposed from the second insulating layer, so the magnetic particles in the magnetic layer can be aligned in the orthogonal direction.

In addition, the second corner formed by the other side and the side has a portion in which the length between the two side surfaces facing each other becomes longer as they approach the other side, and therefore in the magnetic layer that covers the portion through the second insulating layer Corresponding to a part of the second corner, the magnetic particles can be aligned in a direction inclined with respect to the orthogonal direction.

Therefore, a smooth magnetic circuit can be formed around the second corner portion. Therefore, the wiring circuit board has higher inductance.

The present invention (8) includes the wiring circuit board according to any one of (2) to (4), wherein the wiring has a substantially circular shape, the second insulating layer covers a peripheral surface of the wiring, and the particles include The peripheral surface of the wiring is covered with the second insulating layer.

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 magnetic permeability around the wiring can be improved. As a result, the wiring circuit board has a high inductance.

The present invention (9) includes a method for manufacturing a printed circuit board, which includes: a first step of preparing a first insulating layer and wiring arranged on one side in the thickness direction of the first insulating layer; and a second step of The wiring is covered with a second insulating layer; and in a third step, a particle-containing layer is formed, the particle-containing layer covers the wiring with the second insulating layer interposed therebetween, and contains a conductive material having a shape having an aspect ratio of 2 or more And the wiring is formed into a substantially curved shape, and in the second step, a particle-containing sheet containing the conductive particles aligned in a direction orthogonal to the thickness direction is heated to the second insulating layer Pressure.

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

However, in the method for manufacturing a printed circuit board, in the first step, the wiring is formed into a substantially curved shape, so that the second insulating layer of the portion of the covered wiring corresponding to the approximately curved shape can be formed thick.

Therefore, it is possible to suppress the penetration of the conductive particles into the second insulating layer and the contact between the conductive particles and the wiring.

Therefore, this manufacturing method can obtain a printed circuit board that ensures the insulation of the second insulating layer.

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

In the second step of the method of manufacturing a printed circuit board as a method of manufacturing a magnetic printed circuit board, a magnetic sheet containing conductive particles aligned in a direction orthogonal to the thickness direction is heated to the second insulating layer. Therefore, the magnetic particles can be aligned along the curved shape of the wiring in the magnetic layer covering the portion of the wiring corresponding to the substantially curved shape through the second insulating layer. That is, it is possible to orient the magnetic particles in the magnetic layer facing the portion of the wiring corresponding to the substantially curved shape in a direction inclined with respect to the thickness direction and the orthogonal direction. Therefore, a smooth magnetic circuit can be formed in the magnetic layer along the portion of the wiring corresponding to the substantially curved shape. Therefore, the effective magnetic permeability around the wiring can be improved. As a result, a printed circuit board having high inductance can be manufactured.

The present invention (11) includes the method for manufacturing a printed circuit board according to (10), wherein the wiring in the first step has a thickness-direction surface and is spaced apart from the thickness-direction surface of the first insulating layer. And oppositely arranged; the other side in the thickness direction is in contact with the one side in the thickness direction of the first insulating layer; and the side surface connects the two edges of the one side in the thickness direction and the other side in the thickness direction; further, at the thickness In the second step, the side of the thickness direction and the side surface of the wiring are covered with the insulating layer in the second step, and in the third step, a gap is formed. The second insulating layer covers the particle-containing layer on the one surface in the thickness direction and the side surface of the wiring.

In the method for manufacturing a printed circuit board, since the corner portion having a substantially curved shape is formed in the wiring in the first step, the second insulating layer covering the corner portion can be formed thicker.

Therefore, it is possible to suppress the penetration of the conductive particles into the second insulating layer and the contact between the conductive particles and the wiring.

Therefore, this manufacturing method can obtain a printed circuit board that ensures the insulation of the second insulating layer.

The present invention (12) includes the method for manufacturing a printed circuit board as described in (11), wherein the first step includes the fourth step: forming a tip having a surface formed by a thickness direction and a side surface by a subtractive method. The wiring base of the protrusion; and, in a fifth step, a plating layer is formed by plating, whereby the corner portion is formed into a substantially curved shape by a covering portion, the plating layer covers the wiring base portion, and has Covering the covered portion of the spike.

However, in the first step, if a wiring having a pointed portion is formed, the thickness of the insulating layer facing the pointed portion may be too thin in the second step. Thereafter, if a magnetic layer is formed in the third step, the magnetic particles penetrate the insulating layer facing the pointed portion and come into contact with the pointed portion. As a result, the contact between the magnetic layer and the wiring cannot be ensured. Insulation situation.

However, even in the fourth step, a wiring base portion having a sharpened portion is formed, and in the fifth step, a plating layer having a covered portion covering the sharpened portion is formed, and the corner portion is formed approximately using the covered portion. Bent shape. Therefore, in the second step, the second insulating layer covering the corner can be formed so as to prevent the second insulating layer from becoming too thin.

By forming the magnetic layer in the third step, it is possible to prevent the magnetic particles in the magnetic layer from penetrating the second insulating layer and making contact with the wiring.

The present invention (13) includes the method for manufacturing a printed circuit board according to (10), wherein the wiring in the first step has a substantially circular shape, and in the second step, the wiring is covered with the insulating layer. In the third step, the peripheral surface of the wiring is formed with a particle-containing layer covering the peripheral surface of the wiring with the second insulating layer interposed therebetween.

In the third step, in the magnetic layer around the wiring, the magnetic particles can form a smooth magnetic circuit along the substantially curved shape of the wiring. Therefore, the effective magnetic permeability around the wiring can be improved. As a result, a printed circuit board having high inductance can be manufactured.
[Effect of the invention]

The printed circuit board of the present invention obtained by the method for manufacturing a printed circuit board of the present invention can ensure the insulation of the second insulating layer.

〈One embodiment〉
A magnetic wiring circuit board 1 which is an embodiment of the wiring circuit board of the present invention will be described with reference to FIG. 1.

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

The first insulating layer 2 has a shape extending in the plane direction. The first insulating layer 2 is a supporting material that supports the wiring portion 3 described below, and also a supporting layer that supports the magnetic wiring circuit substrate 1.
The first insulating layer 2 includes a first insulating surface 7 as one surface in the thickness direction, and a second insulating surface 8 as the other surface in the thickness direction. The first insulating surface 7 and the second insulating surface 8 are flat surfaces along the plane direction, respectively. The first 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. The first insulating layer 2 may be a single layer or a plurality of layers. The thickness of the first insulating layer 2 is not particularly limited, and is, for example, 1 μm to 1,000 μm.

For example, the cut surface obtained by cutting the first insulating surface 7 of the first insulating layer 2 along the thickness direction and the first direction (corresponding to the left-right direction in FIG. 1 and the direction including the surface direction), A plurality of wiring portions 3 are arranged at intervals in the first direction. The shape of the wiring portion 3 in plan view (when viewed in the thickness direction) is not particularly limited, and includes, for example, a ring shape (coil shape, etc.).

The wiring section 3 is provided with a first wiring surface 9 that is opposite to the thickness direction side of the first insulating surface 7 of the first insulating layer 2 and is disposed opposite to the thickness direction side; a second wiring surface 10 that It is in contact with the first insulating surface 7 of the first insulating layer 2; and the wiring side surface 11 is a side surface that connects the first wiring surface 9 and the second wiring surface 10 at both ends in the first direction.

The first wiring surface 9 is a flat surface along the first direction.

The second wiring surface 10 is a flat surface that is disposed opposite to the first wiring surface 9 in a thickness direction and is parallel to the first wiring surface 9.

The wiring side surface 11 extends in the thickness direction. The wiring side surface 11 includes two wiring sections 3. The two wiring side surfaces 11 are arranged to face each other (to face each other) at intervals in the first direction.

The wiring portion 3 includes a first corner portion 21 and a second corner portion 22 as an example of the corner portion.

The first corner portion 21 is a ridgeline portion (first ridgeline portion) formed by the first wiring surface 9 and the wiring side surface 11 in the wiring portion 3. Specifically, the first corner portion 21 is formed across each of both ends in the first direction of the first wiring surface 9 and one end portion in the thickness direction that is continuous to the wiring side surfaces 11. Two first corner portions 21 are formed for each wiring portion 3.

The first corner portion 21 has a substantially curved shape in a cross-sectional view (on a cut surface along the thickness direction and the first direction). Specifically, the first corner portion 21 has a curved surface (specifically, a substantially circular arc surface) 23 that bulges outward in the first direction and one side in the thickness direction.

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

The radius (curvature radius) 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, still more preferably 20 μm or more, and 30 μm or less, for example. If the curvature radius R of the curved surface 23 is greater than or equal to the above-mentioned lower limit, the curved surface 23 can be made gentle, and the second insulating layer 4 described below can be formed more accurately with a sufficient thickness T. In addition, the magnetic particles 18 (described below) can be accurately aligned along the curved surface 23 on the second insulating layer 4 facing the first corner portion 21.

When the curvature radius R of the first corner portion 21 is equal to or smaller than the above-mentioned upper limit, the magnetic layer 5 can be filled in the thickness-direction central portion 50 (described below) of the wiring side surface 11 without gaps (voids).

The central angle α of the curved surface 23 is an angle formed by a line segment connecting one end of the arc and the center CP and a line segment connecting the other end of the arc and the center CP, for example, less than 180 degrees. Specifically, the center 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, for example, 150 degrees or less, preferably 135 degrees or less, and more preferably 120 degrees. Degrees below. If the central angle α of the curved surface 23 is greater than or equal to the above-mentioned lower limit, the length of the curved surface 23 can be made longer. Therefore, the magnetic particles 18 can be accurately (orientated) along the curved surface 23. If the central angle α of the curved surface 23 is greater than or equal to the above-mentioned lower limit, the length of the curved surface 23 can be made longer. Therefore, the magnetic particles 18 can be accurately (orientated) along the curved surface 23. When the center angle α of the curved surface 23 is equal to or less than the above-mentioned upper limit, the magnetic layer 5 can be filled in the thickness-direction central portion 50 (described below) of the wiring side surface 11 without gaps (voids).

Furthermore, as shown in the enlarged view of FIG. 1, the circle C forming the curved surface 23 is defined as a circle C based on a center CP which is formed in the first corner 21 to pass through (overlap) the curve as much as possible. The arc of the face 23 determines the center CP. Instead of the circle C 'based on the center CP', the center CP 'is shown in FIG. 3 and formed in the first corner 21 to pass (overlay) the arc of the curved surface 23 slightly (minimally), Decision center CP '.

The second corner portion 22 is a ridgeline portion (second ridgeline portion) formed by the second wiring surface 10 and the wiring side surface 11 in the wiring portion 3. Specifically, the second corner portion 22 is formed across each of the two end portions in the first direction of the second wiring surface 10 and the other end portion in the thickness direction that is continuous to the wiring side surfaces 11. Two second corner portions 22 are formed for each wiring portion 3.

Each of the two second corner portions 22 is disposed on the other side in the thickness direction with respect to each of the two first corner portions 21.

The second corner portion 22 is a second spike portion that is outward toward the outside in the first direction (the outside of the first direction is inclined toward the other side in the first direction). The second corner portion 22 has an inclined surface 24 and a flat surface 26 (divided by having both).

The inclined surface 24 has a tapered surface 27 as a main part. Preferably, the inclined surface 24 includes only a tapered surface 27. The inclined surface 24 is continuous from the central portion in the thickness direction of the wiring side surface 11 (specifically, the vicinity between the central portion and the other end portion) 50 and faces outward in the first direction. The two inclined surfaces 24 corresponding to the two second corner portions 22 are arranged to face each other (face each other) in the first direction.

The tapered surface 27 is inclined with respect to the thickness direction and the first direction. That is, the tapered surface 27 is inclined along the thickness direction and the first direction, and is inclined toward the outside of the first direction (the first tilt direction) as it moves toward the other side of the thickness direction (see the enlarged view in conjunction with the enlarged view) Indicates the direction arrow). The two tapered surfaces 27 corresponding to the two inclined surfaces 24 are two tapered surfaces whose length between them becomes longer as they approach the other side in the thickness direction (part of an example). Specifically, the tapered surface 27 faces the edges in the first direction of the second wiring surface 10 so that the central portion (specifically, near the center portion and the other end portion) 50 along the thickness direction of the wiring side surface 11. (The first insulating surface 7 of the first insulating layer 2) is inclined so as to widen toward the outside in the first direction so as to be widened at the ends. The taper (first direction length / thickness direction length) obtained by dividing the first direction length of the tapered surface 27 by the thickness direction length is, for example, 0.001 or more, preferably 0.01 or more, and more preferably 0.1 or more. It is 1.0 or less, and preferably 0.75 or less.

The flat surface 26 is a plane that extends straight from the other end edge on the other side in the thickness direction of the inclined surface 24 toward the inside in the first direction. The flat surface 26 corresponds to both ends of the second wiring surface 10 in the first direction. The flat surface 26 is in contact with the first insulating surface 7.

The inclined surface 24 of the second corner portion 22 and the curved surface 23 of the first corner portion 21 are arranged, for example, across the thickness-direction central portion 50 of the wiring side surface 11.

It should be noted that the second corner portion 22 may have the same shape as the second spike portion 45 (see FIG. 2A) of the wiring base portion 36 described below.

The wiring side surface 11 includes a portion of the curved surface 23 of the first corner portion 21 that faces outward in the first direction, a thickness direction central portion 50, and a portion of the inclined surface 24 of the curved surface 23 that faces the outside in the first direction.

In addition, each of the thickness-direction central portions 50 of the two wiring side surfaces 11 has a shape that contracts toward the inside in the first direction. Specifically, the wiring side surface 11 has a shape (constriction) whose length is the shortest at the center portion in the first direction.

Further, as shown by an imaginary line in FIG. 2B, the wiring portion 3 includes, for example, a wiring base portion 36 and a plating layer 30 formed on one surface and both side surfaces in the thickness direction.

Examples of the material of the wiring section 3 include metals such as copper, nickel, gold, and tin, or conductors of alloys of these metals, and preferably copper.

The thickness of the wiring portion 3 is the length between the first wiring surface 9 and the second wiring surface 10, and specifically, it is, for example, 10 μm or more, preferably 30 μm or more, and, for example, 500 μm or less, preferably 250 μm or less.

The width of the wiring portion 3 is the distance between the end edges in the first direction of the two first corner portions 21 facing each other, for example, 20 μm or more, preferably 50 μm or more, and, for example, 2000 μm or less. It is preferably 1000 μm or less.

The interval between the adjacent wiring portions 3 is defined as the interval between the first direction end edges of the adjacent first corner portions 21 via the second insulating layer 4 (described below) and the magnetic layer 5 (described below). 20 μm or more, preferably 50 μm or more, and, for example, 1000 μm or less, and preferably 500 μm or less.
The ratio (thickness / width) of the thickness of the wiring portion 3 to the width of the wiring portion 3 is, for example, 0.005 or more, preferably 0.03 or more, and, for example, 25 or less, and preferably 5 or less. The ratio (thickness / interval) of the thickness of the wiring portion 3 to the interval between adjacent wiring portions 3 is, for example, 0.01 or more, preferably 0.06 or more, and, for example, 25 or less, and 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, for example, 100 or less, and preferably 20 or less.

The wiring portion 3 is provided on the printed circuit board preparation 6 together with the first insulating layer 2. That is, the printed circuit board preparation 6 does not include the second insulating layer 4 and the magnetic layer 5 described below, but includes the first insulating layer 2 and the wiring portion 3. Preferably, the printed circuit board preparation 6 includes only the first insulating layer 2 and the wiring portion 3.

The second insulating layer 4 is provided corresponding to the plurality of wiring portions 3. The second insulating layer 4 is formed in a thin film shape along the first 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 second insulating layer 4 includes a fourth insulating surface 13 that is in contact with the first wiring surface 9 and the wiring side surface 11, and a third insulating surface that is disposed on the thickness direction side of the fourth insulation surface 13 or outside the first direction at intervals. 12.

The fourth insulating surface 13 has a shape corresponding to the first wiring surface 9 and the wiring side surface 11 (specifically, the same).

The third insulating surface 12 has a shape following the fourth insulating surface 13 to ensure the thickness T of the second insulating layer 4. The third insulating surface 12 has a shape parallel to the fourth insulating surface 13.

The second insulating layer 4 is, for example, an electrodeposited layer (described below), a coating layer (described below), or the like, and is preferably an electrodeposited layer.

The second insulating layer 4 is relatively soft, for example (especially, it has a property that it becomes soft during heat pressing in the third step (see FIG. 2D) described below), and is not magnetic. Specifically, as the material of the second insulating layer 4, a resin or the like that does not contain magnetic particles 18 (to be described in detail later in the magnetic layer 5) can be mentioned. The resin of the second insulating layer 4 is preferably a resin having an ionic property in water. Specific examples include acrylic resins, epoxy resins, polyimide resins, and mixtures thereof.

The thickness T of the second insulating layer 4 is relatively thin, and the average thickness is, for example, 20 μm or less, preferably 15 μm or less, more preferably 10 μm or less, even more preferably 7.5 μm, and even more preferably 5 μm or less. Is 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.

If the thickness T of the second insulating layer 4 is less than the above-mentioned upper limit, the effective magnetic permeability of the magnetic layer 5 described below can be increased, thereby increasing the inductance of the magnetic wiring circuit board 1.

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

However, in this magnetic wiring circuit board 1, the first corner portion 21 of the wiring portion 3 has a substantially curved shape, so the thickness T of the second insulating layer 4 can suppress the second insulating layer 4 from becoming too thin and the second insulating layer. 4 is penetrated by the magnetic particles 18 to ensure the insulation of the second insulating layer 4.

In addition, the thickness T1 of the portion of the second insulating layer 4 that covers the first corner portion 21 and the portion of the second insulating layer 4 that covers the first corner portion 21 (for example, the thickness direction central portion 50 of the wiring side surface 11) are allowed. And / or the first wiring surface 9 in the first direction center portion) has the same thickness T0 or is slightly smaller than the thickness T0.

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

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

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

The average thickness of the second insulating layer 4 is calculated by allocating the thicknesses T1 and T0 according to their area ratios.

The magnetic layer 5 is provided for the printed circuit board preparation 6 in order to increase the inductance of the magnetic printed circuit board 1. The magnetic layer 5 has a shape extending in the plane direction.

The magnetic layer 5 is embedded with a wiring portion 3 via a second insulating layer 4. Specifically, the magnetic layer 5 covers the first wiring surface 9 and the wiring side surface 11 (including the curved surface 23 and the inclined surface 24) of the wiring portion 3 via the second insulating layer 4. The magnetic layer 5 covers the first insulating surface 7 of the first insulating layer 2 and covers the exposed surface 16 exposed from the second insulating layer 4.

The magnetic layer 5 includes a first magnetic surface 14 and a second magnetic surface 15.

The first magnetic surface 14 is disposed on the thickness-direction side of the third insulating surface 12 of the second insulating layer 4 at intervals. The first magnetic surface 14 is exposed on one side in the thickness direction. The first magnetic surface 14 includes a plurality of convex portions 28 corresponding to the plurality of wiring portions 3 and protruding toward one side in the thickness direction; and a concave portion 29 disposed between the convex portions 13 adjacent to each other and opposite to The convex portion 28 sinks toward the other side in the thickness direction.

The second magnetic surface 15 is disposed on the other side in the thickness direction of the first magnetic surface 14 at intervals.
The second magnetic surface 15 is continuous with the third insulating surface 12 and the exposed surface 16 and is in contact therewith.

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 and a resin component 19 having an aspect ratio of 2 or more.

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

Examples of the soft magnetic body include: a single metal body containing one metal element in a pure substance state; for example, one or more metal elements (first metal element) and one or more metal elements (second metal element); and The alloy body is the eutectic body (mixture) of non-metal elements (carbon, nitrogen, silicon, phosphorus, etc.). These can be used alone or in combination.

Examples of the single metal body include a metal monomer composed of only one metal element (first metal element). As the first metal element, for example, iron (Fe), cobalt (Co), nickel (Ni), and other metal elements that can be contained as the first metal element of the soft magnetic body are appropriately selected.

Examples of the single metal body include the form of a surface layer including a core containing only one metal element, and a surface layer containing an inorganic substance and / or an organic substance partially or entirely modified from a part of the surface of the core; A form in which the organometallic compound or the inorganic metal compound containing the first metal element is decomposed (such as thermal decomposition). As the latter aspect, an iron powder (sometimes referred to as a carbonyl iron powder) obtained by thermally decomposing an organic iron compound (specifically, carbonyl iron) containing iron as the first metal element may be mentioned. In addition, the position of a layer including a partially modified inorganic substance and / or organic substance containing only one metal element is not limited to the surface as described above. Moreover, as the organometallic compound or the inorganic metal compound capable of obtaining a single metal body, it is not particularly limited, and it can be appropriately selected from known to conventional organometallic compounds or inorganic metal compounds that can obtain a single metal body of the soft magnetic body. .

A blend of more than one metal element (first metal element) and more than one metal element (second metal element) and / or non-metal elements (carbon, nitrogen, silicon, phosphorus, etc.) in the alloy system, as long as it is available It is not particularly limited as long as it is an alloy body of a soft magnetic body.

Examples of essential elements in the first metal element-based alloy include iron (Fe), cobalt (Co), and nickel (Ni). If the first metal element is Fe, the alloy body is called an Fe-based alloy, if the first metal element is Co, the alloy body is called a Co-based alloy, and if the first metal element is Ni, the alloy body is called Ni-based alloy.

The second metal element is an element (secondary component) that is contained in the alloy body in a minor manner, and is a metal element that is fused (co-fused) with the first metal element. For example, iron (Fe) (in the first metal element is (When other than Fe), cobalt (Co) (when the first metal element is other than Co), nickel (Ni) (when the first metal element is 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), yttrium (Y), strontium (Sr), various rare earth elements, and the like. These can be used alone or in combination of two or more.

Non-metallic elements are elements (subcomponents) that are contained in the alloy body, and are non-metallic elements that are compatible (co-fused) with the first metal element. Examples include boron (B), carbon (C), and nitrogen. (N), silicon (Si), phosphorus (P), sulfur (S), and the like. These can be used alone or in combination of two or more.

Examples of the alloy body include Fe-based alloys, for example, magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), and iron-silicon aluminum alloy (Fe-Si-Al alloy) (including super iron silicon aluminum) Alloy), nickel-iron alloy (Fe-Ni alloy), Fe-Ni-Mo alloy, Fe-Ni-Mo-Cu alloy, Fe-Ni-Co alloy, Fe-Cr alloy, Fe-Cr-Al alloy, Fe-Ni -Cr alloy, Fe-Ni-Cr-Si alloy, silicon copper (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 alloy, Fe-Si-Al-Ni-Cr alloy, Fe-Ni-Si-Co alloy, Fe-N alloy, Fe-C alloy, Fe-B Alloys, Fe-P alloys, ferrites (stainless steel-based ferrites, further including Mn-Mg-based ferrites, Mn-Zn-based ferrites, Ni-Zn-based ferrites, Ni-Zn-Cu-based iron (Ferrite, Cu-Zn-based ferrite, Cu-Mg-Zn-based ferrite and other soft ferrite), iron-cobalt alloy (Fe-Co alloy), Fe-Co-V alloy, Fe-based amorphous alloy, etc. .

Examples of the alloy body include a Co-based alloy, and examples thereof include Co-Ta-Zr, a cobalt (Co) -based amorphous alloy, and the like.

An example of the alloy body is a Ni-based alloy, and examples thereof include a Ni-Cr alloy.

Among these soft magnetic bodies, from the viewpoint of self-magnetic properties, alloy bodies are more preferable, Fe-based alloys are more preferable, and iron-silicon aluminum alloys (Fe-Si-Al alloys) are more preferable. From the viewpoint of magnetic permeability, an iron-silicon aluminum alloy containing a Si content of 9 to 15% by mass is particularly preferred. Further, as the soft magnetic body, a single metal body is preferably used, more preferably a single metal body containing iron in a pure substance state, and even more preferably an iron monomer or iron powder (carbonyl iron powder).

Examples of the shape of the magnetic particles 18 include a flat shape (plate shape) having a thin thickness and a wide surface, and an anisotropic shape such as a needle shape. Further, it may further contain non-anisotropic magnetic particles. The non-anisotropic magnetic particles may have a shape such as a spherical shape, a granular shape, a block shape, or a pellet shape. As the shape of the magnetic particles 18, a shape having an anisotropy is preferable.

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, still more preferably 20 or more, and 100 or less.

When the magnetic particles 18 are flat, the flattening ratio (flatness) is, for example, 8 or more, preferably 15 or more, and, for example, 500 or less, and preferably 450 or less. The flattening 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 vol% or more, preferably 55 vol% or more, and, for example, 95 vol% or less, and preferably 90 vol% or less.

Examples of the resin component 19 include thermosetting resins such as an epoxy resin composition containing an epoxy resin, a curing agent, and a curing accelerator. Such a magnetic composition is described in, for example, Japanese Patent Laid-Open No. 2017-005115, Japanese Patent Laid-Open No. 2015-092543, and the like.

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

Next, a method of manufacturing the magnetic wiring circuit board 1 will be described with reference to FIGS. 2A to 2D.

This manufacturing method includes a first step (see FIG. 2A and FIG. 2B) as an example of a step of preparing the first insulating layer 2 and the wiring portion 3, a second step (see FIG. 2C) of forming the second insulating layer 4, and as The third step is an example of the step of forming the magnetic layer 5 (see FIG. 2D).

As shown in FIGS. 2A and 2B, in a first step, a printed circuit board preparation body 6 including a first insulating layer 2 and a wiring portion 3 is prepared. This first step includes a step of preparing a first insulating layer 2 (see FIG. 2A), a fourth step of forming a wiring base 36 (see FIG. 2A), and a fifth step of forming a plating layer 30 (see FIG. 2B).

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

When forming the wiring base portion 36 by the subtractive method, a multilayer body (not shown) including the first insulating layer 2 and a conductor layer (metal layer) is first prepared, and then the thickness of the conductor layer is the same as the pattern of the wiring base portion 36. A resist layer is formed on one side. Then, the conductive layer exposed from the resist layer is patterned by etching such as wet etching and dry etching to form the wiring base 36. The wiring base 36 is preferably formed by wet etching. Thereafter, the resist layer is removed by, for example, peeling.

When the wiring base 36 is formed by the additive method, a conductor film (seed film) is first formed on the first insulating surface 7 of the first insulating layer 2, and then a pattern opposite to the wiring base 36 is formed on the side of the thickness direction of the conductor film. Plating. Then, the wiring base 36 is formed on the conductive film exposed from the anti-plating layer by plating. Thereafter, the anti-plating layer and the corresponding conductive film are removed.

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

On the other hand, if the wiring base portion 36 is formed by the subtractive method, the first spike portion 25 is formed on the wiring base portion 36. However, as described below, the second insulating layer 4 becomes thin due to the first spike portion 25. This situation can be eliminated by using the plating layer 30 formed in the fifth step described below.

The wiring base portion 36 is a base portion (base) for forming the wiring portion 3, and the wiring portion 3 is formed together with the plating layer 30 described below. That is, the wiring portion 3 is not limited to the wiring base portion 36 shown in FIG. 2A.

The wiring base portion 36 includes a first spike portion 25 corresponding to the first corner portion 21, a base portion central side surface 51 corresponding to the thickness direction central portion 50, and a second spike portion 45 corresponding to the second corner portion 22.

The first spiky portion 25 is a ridgeline portion formed on the wiring base portion 36 from one surface and the side surface in the thickness direction. The first spiky portion 25 is sharply pointed toward the outer side of the first direction, and the side of the first direction is sharply pointed. The angle (the angle formed by the ends of the first wiring surface 9 and the wiring side surface 11) of the first spike 25 is, for example, 135 degrees or less, preferably 120 degrees or less, and more preferably 90 degrees or less. It is 30 degrees or more, preferably 45 degrees or more.

The second spike portion 45 is a ridge portion formed on the wiring base portion 36 from the other surface and the side surface in the thickness direction. The second spiky portion 45 inclines sharply toward the outside in the first direction and the other side in the first direction is sharply pointed. The angle (the angle formed by the ends of the second wiring surface 10 and the wiring side surface 11) of the second spike 45 is, for example, 35 ° or more, preferably 45 ° or more, and more preferably 80 ° or more. For example, It is 150 degrees or less, and preferably 135 degrees or less.

The base central side surface 51 is a connecting surface that connects the first spiked portion 25 and the second spiked portion 45 in the thickness direction.

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

In a fifth step, as shown in FIG. 2B, a plating layer 30 is formed on the wiring base 36.

As the material of the plating layer 30, the material of the wiring base portion 36 is appropriately selected, and is preferably the same as the material of the wiring base portion 36.

The plating layer 30 is formed by plating.

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

The plating layer 30 is laminated on one and both sides of the wiring base 36 in the thickness direction by plating. In the plating, the plating layer 30 is formed in a precipitate shape on one side and both sides in the thickness direction of the wiring base portion 36.

By this plating, the first coating portion 31 is deposited on the first spiked portion 25 as an example of a coating portion that grows (plating growth) toward one side in the thickness direction and outside in the first direction. The first covering portion 31 forms a first corner portion 21 including a curved surface 23.

On the other hand, the portion other than the first spike portion 25 of the wiring base portion 36 (the portion including the second spike portion 45 and the thickness-direction central portion 50) grows toward the thickness direction side or the first direction outside (plating) (Growth) second coating portion 32 is deposited. The second covering portion 32 forms one surface and two side surfaces in the thickness direction of the wiring base portion 36 (wherein, the portion except the first corner portion 21 and a portion including the thickness direction central portion 50 and the inclined surface 24).

That is, the plating layer 30 includes a first coating portion 31 and a second coating portion 32. Preferably, the plating layer 30 includes only the first coating portion 31 and the second coating portion 32.

The first coating portion 31 is formed by plating and growing in a substantially radial shape (except for the direction inside the first sharp portion 25, in a fan shape) in section from the first sharp portion 25 by a plating component. Therefore, the first covering portion 31 has a curved surface 23.

On the other hand, with regard to the second coating portion 32, the plating component is oriented in a direction orthogonal to each surface from the surface other than the first spike portion 25. Specifically, the plating component is oriented toward the thickness direction of the wiring base portion 36. The upper side in the thickness direction is grown in a planar form, and on both sides of the wiring base portion 36 (including the side of the second cusp portion 45), the plating components are grown in a plane form toward both outer sides in the first direction. Therefore, the second covering portion 32 does not have the curved surface 23 described above, but includes the first wiring surface 9 and the wiring side surface 11 (including the thickness-direction central portion 50, except for the curved surface 23).

The second covering portion 32 includes a second corner portion 22, and the second corner portion 22 includes an inclined surface 24 based on the plating growth described above.

In the plating layer 30, the thickness (growth thickness or plating thickness) of the first coating portion 31 is preferably thicker than the thickness of the second coating portion 32. If the plating is electrolytic plating, the current density of the first spikes 25 is higher than the current density of the wiring base 36 other than the first spikes 25. Therefore, the plating growth of the first coating portion 31 is faster than the plating growth of the second coating portion 32, so the thickness of the first coating portion 31 is thicker than the thickness of the second coating portion 32.

The thickness of the plating layer 30 is appropriately set according to the growth rate of plating and the plating time. In addition, the growth rate and plating time of the plating are appropriately set according to, for example, the concentration of the metal (conductor) in the plating solution used in the plating, the temperature, and the like. For example, if the plating is electrolytic plating, the The density and distance between electrodes, the degree of stirring in the bath (speed), the concentration of copper sulfate, the concentration of sulfuric acid, the concentration of chloride ions, and the type and amount of additives (leveling agent, brightener, polymerizer) are appropriately set. For example, if plating The coating is electroless plating, and it is appropriately set according to the type, amount, and the like of the catalyst attached to the surface of the wiring base 36.

Further, as shown in FIG. 2B, a boundary indicated by an imaginary line is shown between the wiring base 36 and the plating layer 30. However, if the material of the plating layer 30 and the wiring base 36 are the same, the above Boundaries become unclear or non-existent (unobservable).

In this plating layer 30, the first coating portion 31 is formed by the above-mentioned plating, and thus has the above-mentioned curved surface 23. On the other hand, the second covering portion 32 has an inclined surface 24.

In the second step, as shown in FIG. 2C, a second insulating layer 4 is formed on the above-mentioned printed circuit board preparation 6. Specifically, the first wiring surface 9 and the wiring side surface 11 of the wiring portion 3 are covered by the second insulating layer 4.

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

In the electrodeposition, the wiring circuit board preparation 6 (the magnetic wiring circuit board 1 in the middle of manufacturing) is immersed in an electrodeposition solution containing a resin (preferably an electrodeposition paint), and then a current is applied to the wiring portion 3, whereby A resin film is deposited on the first wiring surface 9 and the wiring side surface 11 of the wiring portion 3. Thereafter, if necessary, the film is dried. Thereby, the second insulating layer 4 is formed as an electrodeposited layer. Thereafter, if necessary, the second insulating layer 4 (electrodeposited layer) is heated by firing to harden it.

In printing as an example of coating, a coating film (screen printing) is applied to the first wiring surface 9 and the wiring side surface 11 of the wiring portion 3 via a screen using a resin-containing varnish. After that, the film was dried.

As a method of forming the second insulating layer 4, electrodeposition is preferably mentioned. In the case of electrodeposition, the thickness T of the second insulating layer 4 can be made thin (but set to a thickness that can secure the insulation of the second insulating layer 4). In addition, in the case of electrodeposition, the second insulating layer 4 can accurately expose the exposed surface 16. Therefore, a magnetic layer can be disposed across the entire thickness direction between adjacent wiring portions 3 in a subsequent third step. 5. Therefore, the effective magnetic permeability of the magnetic layer 5 can be improved, so that the inductance of the magnetic wiring circuit substrate 1 becomes high.

In the third step, as shown in FIG. 2D, a magnetic layer 5 is formed on the printed circuit board preparation 6. Specifically, the first wiring surface 9 and the wiring side surface 11 of the wiring portion 3 are covered by the magnetic layer 5 through the second insulating layer 4.

In the third step, for example, as shown in FIG. 2C, a magnetic sheet 17 as an example of a particle-containing sheet is first prepared. When the magnetic sheet 17 is prepared, for example, a magnetic composition containing the above-mentioned 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 aligned (aligned) along the surface direction (the direction orthogonal to the thickness direction) of the magnetic sheet 17.

Thereafter, as shown by an arrow in FIG. 2C, the magnetic sheet 17 is hot-pressed against the second insulating layer 4 of the printed circuit board preparation 6. The magnetic sheet 17 is arranged on one side in the thickness direction of the printed circuit board preparation 6, and the magnetic sheet 17 is hot-pressed on one side of the printed circuit board preparation 6 in the thickness direction.

Thereby, the wiring sheet 3 is buried in the magnetic sheet 17 via the second insulating layer 4. Specifically, the magnetic sheet 17 covers the first wiring surface 9 of the second insulating layer 4 via the second insulating layer 4 and enters (sinks) between the adjacent wiring portions 3 (16 pairs of exposed surfaces). To the part), and filled in between (part).

In the magnetic sheet 17 before and after the hot pressing, the alignment direction (specifically, the surface direction) of the magnetic particles 18 facing the first wiring surface 9 of the wiring portion 3 does not change. In the magnetic sheet 17 before and after the hot pressing, the alignment 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 the hot pressing, the alignment direction (specifically, the surface direction) of the magnetic particles 18 opposed to the first corner 21 is in the direction along the curved surface 23 (that is, As it goes toward the other side in the thickness direction, it fluctuates in an oblique direction that is inclined outward in the first direction). That is, the magnetic particles 18 are aligned along the curved surface 23.

Furthermore, in the magnetic sheet 17 before and after the hot pressing, the alignment direction (specifically, the surface direction) of the magnetic particles 18 opposed to the second corner portion 22 is in the direction along the inclined surface 24 (that is, as the Toward the other side in the thickness direction and in an oblique direction inclined outward in the first direction). That is, the magnetic particles 18 are aligned along the inclined surface 24.

On the other hand, in the magnetic sheet 17 before and after the hot pressing, the alignment direction (specifically, the surface direction) of the magnetic particles 18 facing the wiring side surface 11 and the first corner portion 21 and the second corner portion 22. It changes in the direction along the thickness direction. That is, the magnetic particles 18 are aligned in the thickness direction.

Thereby, the magnetic sheet 17 is formed (molded) so as to cover the wiring portion 3 with the second insulating layer 4 interposed therebetween, and the magnetic layer 5 having the convex portions 28 and the concave portions 29.

The magnetic particles 18 aligned in the magnetic layer 5 as described above form a smooth magnetic circuit surrounding the wiring portion 3.

Thereby, the magnetic wiring circuit board 1 provided with the printed circuit board preparation body 6 and the magnetic layer 5 can be obtained. The magnetic wiring circuit board 1 preferably includes only the wiring circuit board preparation 6 and the magnetic layer 5.

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

The magnetic wiring circuit board 1 can be used for, for example, wireless power transmission (wireless power feeding and / or wireless power receiving), wireless communication, sensors, passive parts, and the like.

Further, in the magnetic wiring circuit board 1, the first corner portion 21 of the wiring portion 3 (the portion corresponding to the substantially curved shape in the wiring portion 3) has a substantially curved shape, so that the first corner portion 21 covering the first corner portion 21 can be covered. 2 The insulating layer 4 is formed so as to prevent it from becoming too thin. Therefore, the magnetic particles 18 can be prevented from penetrating the second insulating layer 4 and coming into contact with the wiring portion 3. As a result, the insulation property of the magnetic layer 5 to the wiring portion 3 can be secured by the second insulating layer 4.

Moreover, in the magnetic layer 5 covering the first corner portion 21 with the second insulating layer 4 interposed therebetween, the magnetic particles 18 can be aligned along the curved shape of the first corner portion 21. That is, the magnetic particles 18 are along the thickness direction in the magnetic layer 5 facing the first wiring surface 9 of the wiring portion 3, and in the magnetic layer 5 facing the wiring side surface 11 of the wiring portion 3, along the thickness direction. The alignment is aligned in the magnetic layer 5 facing the first corner portion 21 in a direction inclined with respect to the thickness direction and the first direction. Therefore, a smooth magnetic circuit surrounding the wiring portion 3 can be formed in the magnetic layer 5. Therefore, the effective magnetic permeability around the wiring portion 3 can be improved. As a result, the magnetic wiring circuit board 1 has a high inductance.

Therefore, the magnetic wiring circuit board 1 has high inductance, and the second insulating layer 4 has excellent insulation properties.

Moreover, in this magnetic wiring circuit board 1, if the second insulating layer 4 is an electrodeposited layer, the thickness of the second insulating layer 4 can be made thin. Therefore, it is possible to suppress a decrease in the effective magnetic permeability of the magnetic layer 5 covering the wiring portion 3 via the second insulating layer 4. As a result, the magnetic wiring circuit board 1 has a high inductance.

On the other hand, when the thickness of the second insulating layer 4 as shown in FIG. 9A, specifically, the thickness T1 of the second insulating layer 4 facing the first pointed portion 25 is thin, as shown in FIG. 9B As shown, the magnetic particles 18 easily penetrate the thin second insulating layer 4 and come into contact with the wiring portion 3. However, in the magnetic wiring circuit board 1, as shown in FIG. 1, the first corner portion 21 of the wiring portion 3 has a substantially curved shape, and the thickness of the second insulating layer 4 covering the first corner portion 21 is suppressed from being excessively thin. Therefore, penetration of the magnetic particles 18 into the second insulating layer 4 can be suppressed, and the insulation of the second insulating layer 4 can be ensured.

Further, in the magnetic wiring circuit board 1, if the curvature radius R of the first corner portion 21 is as high as 9 μm or more, the curved surface 23 is relatively gentle, so that a first portion corresponding to the first corner portion 21 can be formed with a sufficient thickness T1 2 Insulation layer 4. In the second insulating layer 4 facing the first corner 21, the magnetic particles 18 can be aligned along the curved surface 23 exactly.

In addition, if the average thickness T of the second insulating layer 4 is as thin as 10 μm or less, it is possible to suppress a decrease in the effective magnetic permeability of the magnetic layer 4. As a result, the magnetic wiring circuit board 1 has a high inductance.

In the magnetic wiring circuit board 1, the magnetic layer 5 covers the exposed surface 16. Therefore, the magnetic particles 18 in the magnetic layer 5 can be aligned in the plane direction.

In addition, the second corner portion 22 formed by the second wiring surface 10 and the wiring side surface 11 of the wiring portion 3 has a tapered shape in which the length between the two wiring side surfaces 11 facing each other becomes closer to the second wiring surface 10. In the magnetic layer 5 covered with the second insulating layer 4, the magnetic particles 18 can be aligned in a direction inclined with respect to the first direction, corresponding to the tapered surface 27.

Therefore, a smooth magnetic circuit can be formed around the second corner portion 22. Therefore, the magnetic wiring circuit board 1 has higher inductance.

However, as shown in FIGS. 9A and 9B, in the second step, when the magnetic sheet 17 is heat-pressed against the second insulating layer 4, the magnetic particles 18 contained in the magnetic sheet 17 easily penetrate the second insulation. The layer 4 is in contact with the wiring portion 3.

However, as shown in FIG. 2B, in the manufacturing method of the magnetic wiring circuit board 1, in the first step, the first corner portion 21 having a substantially curved shape is formed on the wiring portion 3. Therefore, as shown in FIG. 2C, The second insulating layer 4 covering the first corner portion 21 is formed thickly.

Therefore, penetration of the magnetic particles 18 into the second insulating layer 4 and contact between the magnetic particles 18 and the wiring can be suppressed.

Therefore, this manufacturing method can obtain the magnetic wiring circuit board 1 having excellent insulation properties of the second insulating layer 4.

In the second step, the magnetic sheet 17 containing the magnetic particles 18 aligned in the planar direction is hot-pressed against the second insulating layer 4, so that the first corner portion 21 is covered with the second insulating layer 4 interposed therebetween. In the magnetic layer 5, the magnetic particles 18 can be aligned along the curved shape of the first corner portion 21. That is, the magnetic particles 18 can be aligned along the plane direction in the magnetic layer 5 facing the first wiring surface 9 of the wiring portion 3, and can be aligned along the magnetic layer 5 facing the wiring side surface 11 of the wiring portion 3. Orientation in the thickness direction is performed in the magnetic layer 5 facing the first corner 21 in a direction inclined with respect to the thickness direction and the first direction. Therefore, a smooth magnetic circuit surrounding the wiring portion 3 can be formed in the magnetic layer 5. Therefore, the effective magnetic permeability around the wiring portion 3 can be improved. As a result, the magnetic wiring circuit board 1 having high inductance can be manufactured.

Therefore, this manufacturing method can obtain a magnetic wiring circuit board 1 having a high inductance and excellent insulation properties of the second insulating layer 4.

However, as shown in FIG. 2A, in the first step, the wiring portion 3 having a sharp portion is formed, as shown in FIG. 9A, in the second step, the second portion opposed to the first sharp portion 25 The thickness T1 of the insulating layer 4 is liable to become too thin. Thereafter, as shown in FIG. 9B, if the magnetic layer 5 is formed in the third step, the magnetic particles 18 will be in contact with the wiring portion 3, so the insulation between the magnetic layer 5 and the wiring portion 3 cannot be ensured.

However, as shown in FIG. 2A, in the fourth step, the wiring base 36 having the first spikes 25 is formed, as shown in FIG. 2B. In the plating layer 30 of the first covering portion 31 of 25, the first corner portion 21 is formed into a substantially curved shape from the first covering portion 31. Therefore, as shown in FIG. 2C, in the second step, the second insulating layer 4 covering the first corner portion 21 can be prevented from becoming too thin, that is, with a thickness T1 (refer to FIG. 1 for an enlargement) (Figure) formation.

As shown in FIG. 2D, in the third step, the magnetic layer 5 is formed, and the magnetic particles 18 in the magnetic layer 5 can be prevented from penetrating the second insulating layer 4 and coming into contact with the wiring portion 3.

＜ Modifications ＞
In each of the following modifications, the same components and steps as those of the above-mentioned embodiment are marked with the same reference numerals, and detailed descriptions thereof are omitted. In addition, each modification can achieve the same effect as that of the embodiment except that it is specifically described. Furthermore, an embodiment and its modifications can be appropriately combined.

In one embodiment, as an example of the printed circuit board of the present invention, a magnetic printed circuit board 1 including a magnetic layer 5 has been described. Although not shown, the present invention is not limited to this, and a printed circuit board including 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 in 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 tin particles.

To obtain a wiring circuit board having a particle-containing layer, it is necessary to refer to FIG. 2C, prepare the particle-containing sheet instead of the magnetic sheet 17, and heat-press the particle-containing sheet with respect to the wiring circuit board preparation 6.

Further, in the printed circuit board, the first corner portion 21 of the wiring portion 3 has a substantially curved shape, so that the second insulating layer 4 covering the first corner portion 21 can be formed so as to prevent the second insulating layer 4 from becoming too thin. Therefore, it is possible to prevent the conductive particles from penetrating the second insulating layer 4 and coming into contact with the wiring portion 3. As a result, the second insulating layer 4 can ensure the insulation of the particle-containing layer to the wiring portion 3.

However, in the second step, when the particle-containing sheet is hot-pressed on the second insulating layer 4, the conductive particles contained in the particle-containing sheet easily penetrate the second insulating layer 4 and come into contact with the wiring.

However, in the method for manufacturing a printed circuit board, in the first step, the first corner portion 21 having a substantially curved shape is formed on the wiring portion 3, so that the second insulating layer 4 covering the first corner portion 21 can be formed. Get thicker.

Therefore, penetration of the conductive particles into the second insulating layer 4 and contact between the conductive particles and the wiring portion 3 can be suppressed.

Therefore, this manufacturing method can obtain a printed circuit board that ensures the insulation of the second insulating layer 4.

Therefore, this printed circuit board can ensure the insulation of the second insulating layer 4.

As shown in FIG. 1, in one embodiment, one wiring portion 3 has a constricted portion whose length between the two wiring side surfaces 11 is the shortest in the central portion in the first direction. However, as shown in FIG. 4, the wiring portion 3 may have a wiring side surface 11 that does not include a constricted portion.

FIG. 1 in one embodiment shows an example where the thickness of 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 relatively thin compared with the thickness of the plating layer 30 in one embodiment.

In this modification, the radius of curvature R of the circle C forming the curved surface 23 is relatively small, and the center angle α is also small. The curvature radius R is, for example, less than 9 μm, further 5 μm or less, and further 2 μm or less, and the central angle α does not reach 110 degrees.

Although the radius of curvature R in this modification is smaller than the radius of curvature R in one embodiment, the second insulating layer 4 corresponding to the curved surface 23 can be formed with a sufficient thickness in the same manner as in the embodiment.

As shown in FIG. 1, in one embodiment, the second corner portion 22 includes an inclined surface 24 having a tapered surface 27. However, as shown in FIG. 5, the second corner portion 22 may have a vertical surface 33 formed perpendicular to the flat surface 26 instead of the inclined surface 24.

The lengths between the two vertical surfaces 33 facing each other are the same as they go toward the other side in the thickness direction.

As shown in FIG. 6, the inclined surface 24 may have a second tapered surface (first narrowed surface) 34 that narrows toward the inner side in the first direction as it goes toward the first insulating surface 7 instead of going toward the 2 The wiring surface 10 is a tapered surface 27 that widens toward the outside in the first direction and has a wide end.

Such a second tapered surface (first narrowed surface) 34 is formed by, for example, an addition method.

As shown in FIG. 1, in one embodiment, the inclined surface 24 includes only a tapered 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 second curved surface 35. The second curved surfaces 35 adjacent to each other are the second narrowed surfaces 37 whose length becomes shorter as they go toward the first insulating surface 7. In this case, the wiring side surface 11 is continuously provided with a portion of the curved surface 23 of the first corner portion 21 facing outward in the first direction, a thickness direction central portion 50, and a tapered surface 27 and a second narrowing of the inclined surface 24.面 37。 Face 37.

In one embodiment, as shown in FIG. 1A to FIG. 1B, the wiring portion 3 includes a flat surface (for example, the first wiring surface 9 and the second wiring surface 10). It has a substantially circular shape in cross section without a flat surface.

Specifically, the wiring portion 3 has a substantially circular shape when cut in a cross section orthogonal to the direction (conveyance direction) (depth direction on the paper surface) of the conveyance current. The wiring section 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, for example, 2000 μm or less, and preferably 200 μm or less.

The second insulating layer 4 covers the wiring peripheral surface 37 of the wiring portion 3. The second insulating layer 4 is formed with a uniform thickness along the first peripheral surface 37, and specifically has a substantially annular shape in cross section. The second insulating layer 4 has an inner peripheral surface that is 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 first insulating surface 7 of the first insulating layer 2.

The thickness T of the second insulating layer 4 is the 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 via the second insulating layer 4.

In the magnetic layer 5, the magnetic particles 18 are aligned near the second insulating layer 4 along the wiring peripheral surface 46 of the wiring portion 3, and specifically, along the insulating peripheral surface 47 of the second insulating layer 4. The area near the second insulating layer 4 is defined as, for example, an area within 1.5 times the radius of the wiring portion 3.

As shown in FIG. 8A, in order to manufacture the magnetic wiring circuit board 1, first a first insulating layer 2 needs to be prepared. In addition, the wiring portion 3 and the second insulating layer 4 are prepared. The wiring portion 3 and the second insulating layer 4 can be prepared as commercially available enameled wires.

Then, as shown in FIG. 8B, the other end edge in the thickness direction of the second insulating layer 4 is disposed on the first insulating surface 7 of the first insulating layer 2. Thereby, the first step and the second step are performed simultaneously.

Thereafter, the magnetic sheet 17 is hot-pressed against the first insulating layer 2, the wiring portion 3, and the second insulating layer 4 (implementation of the third step).

Thereby, in the second insulating layer 4, in the vicinity of the second insulating layer 4, the magnetic particles 18 can follow the wiring peripheral surface 46 of the wiring portion 3, specifically, along the insulating peripheral surface of the second insulating layer 4. 47Alignment.

Thereby, the magnetic wiring circuit board 1 provided with the 1st insulation layer 2, the wiring part 3, the 2nd insulation layer 4, and the magnetic layer 5 is obtained.

Further, in this magnetic wiring circuit board 1, in the magnetic layer 5 around (the vicinity of) the wiring portion 3 (the second insulating layer 4), the magnetic particles 18 can be formed along the wiring peripheral surface 46, specifically, along the wiring peripheral surface 46. The smooth magnetic circuit of the insulating peripheral surface 47. Therefore, the effective magnetic permeability around the wiring portion 3 can be improved. As a result, the magnetic wiring circuit board 1 has a high inductance.

In the method for manufacturing the magnetic wiring circuit board 1, in the third step, the magnetic particles 18 can be formed along the wiring portion in the magnetic layer 5 around the wiring portion 3 (second insulating layer 4) (in the vicinity). 3 is a smooth magnetic circuit with a roughly curved shape. Therefore, the effective magnetic permeability around the wiring portion 3 can be improved. As a result, the magnetic wiring circuit board 1 having high inductance can be manufactured.

In addition, the ratio of the magnetic particles 18 in the magnetic layer 5 may be the same as that in the magnetic layer 5, and may also increase or decrease as the distance from the wiring portions 3 increases.

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

The above invention is provided as an exemplary embodiment of the present invention, but it is only an example and should not be interpreted in a limited manner. Variations of the present invention that are known to those skilled in the art are included in the scope of the following patent applications.
[Industrial availability]

The printed circuit board can be used for magnetic applications.

1‧‧‧ Magnetic wiring circuit board (an example of a wiring circuit board)

2‧‧‧The first insulation layer

3‧‧‧Wiring section (an example of wiring)

4‧‧‧Second insulation layer

5‧‧‧ Magnetic layer (an example of a layer containing particles)

6‧‧‧ Wiring circuit board preparation

7‧‧‧The first insulation surface

8‧‧‧Second insulation surface

9‧‧‧The first wiring surface

10‧‧‧ 2nd wiring surface

11‧‧‧ side of wiring

12‧‧‧ 3rd insulation surface

13‧‧‧ 4th insulation surface

14‧‧‧ 1st magnetic surface

15‧‧‧ 2nd magnetic surface

16‧‧‧ exposed

17‧‧‧Magnetic sheet (example of particle sheet)

18‧‧‧ magnetic particles

19‧‧‧ resin composition

21‧‧‧The first corner

22‧‧‧ 2nd corner

23‧‧‧ curved surface (circular surface)

24‧‧‧ inclined surface

25‧‧‧ Spire

26‧‧‧ flat surface

27‧‧‧ tapered surface

28‧‧‧ convex

29‧‧‧ recess

30‧‧‧Plating

31‧‧‧The first covered part

32‧‧‧ 2nd covered section

33‧‧‧Vertical plane

34‧‧‧ 2nd tapered surface (1st narrowed surface)

35‧‧‧ 2nd curved surface

36‧‧‧Wiring base

37‧‧‧ 2nd narrow face

45‧‧‧ 2nd cusp

46‧‧‧ Wiring surface

47‧‧‧ Insulated peripheral surface

50‧‧‧ thickness center

51‧‧‧ Central side of base

C‧‧‧circle

C'‧‧‧ round

CP‧‧‧ Center

CP'‧‧‧ Center

R‧‧‧ radius of curvature

T‧‧‧thickness of the second insulation layer (average thickness)

T0‧‧‧thickness

T1‧‧‧thickness

α‧‧‧ Center Angle

β1‧‧‧ angle

β2‧‧‧ angle

FIG. 1 shows a cross-sectional view of a magnetic wiring circuit board as an embodiment of the wiring circuit board of the present invention and an enlarged sectional view of a part thereof.

2A to 2D are manufacturing steps of the magnetic wiring circuit board shown in FIG. 1. FIG. 2A shows a fourth step (first step) of forming a wiring base, and FIG. 2B shows a fifth step of forming a plating layer and forming wiring. Step (first step), FIG. 2C shows a second step of forming a second insulating layer, and FIG. 2D shows a third step of forming a magnetic layer.

3 is a cross-sectional view illustrating a circle passing through a curved surface of a curved surface of a first corner portion in FIG. 1.

FIG. 4 is an enlarged cross-sectional view of a part of FIG. 1 showing a modified example of the magnetic wiring circuit board (a state where the plating layer is thin and the wiring side does not have a shrinkage).

FIG. 5 is an enlarged cross-sectional view of a portion of FIG. 1 showing a modified example of the magnetic wiring circuit board (a state where the second corner portion has a vertical plane).

FIG. 6 is an enlarged sectional view of a part of FIG. 1 showing a modified example of the magnetic wiring circuit board (a state where the second corner portion has the first narrowed surface).

FIG. 7 is an enlarged sectional view of a part of a modified example of the magnetic wiring circuit board (a state in which the second corner portion has the second narrowed surface) in FIG. 1.

FIGS. 8A to 8C are manufacturing process diagrams of a modified example of the magnetic wiring circuit board shown in FIG. 1 (the wiring portion is substantially circular in cross-section), and FIG. 8A shows preparation of a first insulating layer, a wiring portion, and a second In the step of the insulating layer, FIG. 8B shows the step of disposing the wiring portion and the second insulating layer on the first insulating layer, and FIG. 8C shows the step of thermally pressing the magnetic sheet to the first insulating layer, the wiring portion and the second insulating layer. step.

FIGS. 9A to 9B are diagrams showing the manufacturing steps of a magnetic wiring circuit board of a comparative example. FIG. 9A shows a second step of forming a second insulating layer, and FIG. 9B shows a third step of forming a magnetic layer.

Claims (13)

A wiring circuit substrate, comprising: First insulation layer; The wiring is arranged on one side in the thickness direction of the first insulating layer; A second insulating layer covering the wiring; and A particle-containing layer containing conductive particles having a shape having an aspect ratio of 2 or more, and covering the wiring via the second insulating layer; and The wiring has a substantially curved shape. The printed circuit board according to claim 1, wherein the conductive particles are magnetic particles, The particle-containing layer is a magnetic layer, and This wiring circuit board is a magnetic wiring circuit board. The printed circuit board according to claim 2, wherein the second insulating layer is an electrodeposited layer. The printed circuit board according to claim 2, wherein the average thickness T of the second insulating layer is 10 μm or less. The wiring circuit board according to claim 2, wherein the wiring has: one surface in a thickness direction, which is arranged opposite to the one surface in the thickness direction of the first insulating layer, and the other surface in the thickness direction, which is opposite to the first insulating layer One side of the thickness direction is in contact with one side; and a side surface that connects two end edges of the one surface in the thickness direction and the other side in the thickness direction; The second insulating layer covers the one surface in the thickness direction and the side surface, The wiring has a corner portion formed by the one surface in the thickness direction and the side surface; and The corner portion has a substantially curved shape. The wiring circuit board according to claim 5, wherein the radius of curvature R of the corner is 9 μm or more. The printed circuit board according to claim 5, wherein the magnetic layer covers the first insulating layer and the thickness direction surface exposed from the second insulating layer, The wiring has a second corner formed by the other surface in the thickness direction and the side surface; and The second corner portion has a portion in which a length between the two side surfaces facing each other becomes longer as it approaches the other side in the thickness direction. The wiring circuit board of claim 2, wherein the wiring has a substantially circular shape, The second insulating layer covers a peripheral surface of the wiring, and The particle-containing layer covers the peripheral surface of the wiring via the second insulating layer. A method for manufacturing a wiring circuit substrate, comprising: The first step is to prepare a first insulating layer and wiring arranged on one side in the thickness direction of the first insulating layer; The second step is to cover the wiring with a second insulating layer; and The third step is to form a particle-containing layer which covers the wiring via the second insulating layer and contains conductive particles having a shape having an aspect ratio of 2 or more; and The wiring is formed into a substantially curved shape, In the second step, the particle-containing sheet containing the conductive particles aligned in a direction orthogonal to the thickness direction is hot-pressed on the second insulating layer. The method for manufacturing a printed circuit board according to claim 9, wherein the conductive particles are magnetic particles, The particle-containing layer is a magnetic layer, The particle-containing sheet is a magnetic sheet, and This manufacturing method is a manufacturing method of a magnetic wiring circuit board. For example, the method for manufacturing a printed circuit board according to claim 10, wherein the wiring in the first step has: a thickness direction surface, which is oppositely disposed on the thickness direction surface of the first insulation layer, and is oppositely disposed; One surface is in contact with the thickness direction of the first insulating layer; and a side surface connects the two edges of the one surface in the thickness direction and the other surface in the thickness direction; further, the one surface in the thickness direction and the side surface are formed roughly. Corners of curved shapes; and In the second step, the thickness-direction surface and the side surface of the wiring are covered with the insulation layer. In the third step, a particle-containing layer is formed to cover the one surface in the thickness direction and one side of the wiring via the second insulating layer. The method of manufacturing a printed circuit board according to claim 11, wherein the above first step includes: The fourth step is to form a wiring base having a pointed portion formed by one side and the side in the thickness direction by a subtractive method; and, The fifth step is to form a plating layer by plating, thereby forming the corner portion into a substantially curved shape by using a covering portion, the plating layer covering the wiring base portion, and having the coating covering the pointed portion. unit. The method of manufacturing a printed circuit board according to claim 10, wherein the wiring in the first step has a substantially circular shape, and In the second step, the peripheral surface of the wiring is covered with the insulating layer. In the third step, a particle-containing layer covering the peripheral surface of the wiring with the second insulating layer formed thereon is formed.