JP7414082B2 - inductor parts - Google Patents

Description

The present invention relates to inductor components.

In recent years, electronic devices such as notebooks, smartphones, and digital TVs have become smaller and thinner. Along with this, inductor components installed in electronic devices are also required to be surface-mounted, small, and thin components that can reduce the mounting area.

For example, IVR technology is a technology that integrates a voltage regulator system within an IC package to save power and reduce the size of the IC package. In order to realize this technology, it is necessary to create a small and thin power inductor that can be built into an IC package.

In addition, smart cards must have a voltage regulator, battery charger, etc. inside the card, and the card thickness must be 0.76 mm (ISO/IEC 7810 standard). Therefore, a thin inductor that can be mounted even on thin cards is required.

Conventionally, there is a surface-mounted thin inductor component described in Japanese Patent No. 6024243 (Patent Document 1). The inductor component includes a spiral wiring wound on a plane of a printed circuit board, and a first magnetic layer and a second magnetic layer located at positions sandwiching the spiral wiring. In other words, by forming spiral wiring on the top and bottom surfaces of a printed circuit board and filling the surrounding area with magnetic material, magnetic resistance is reduced and an inductor component with high inductance acquisition efficiency is achieved.

Patent No. 6024243

By the way, when further thinning is promoted, the influence of variations during manufacturing becomes even greater. Specifically, although the thickness of each part of the inductor component becomes smaller due to the reduction in thickness, the amount of variation in the thickness of each part does not necessarily become smaller even if the inductor component is made thinner. For example, in the prior art, the thickness of the first magnetic layer and the second magnetic layer is adjusted by grinding the surfaces, but the grinding accuracy depends not on the thickness of the inductor component but on the equipment and manufacturing process. Therefore, in this case, due to the thinning, the variation in the thickness of the first magnetic layer and the second magnetic layer becomes relatively large.

As described above, the thicknesses of the first magnetic layer and the second magnetic layer affect the inductance acquisition efficiency, so if the variations in these thicknesses increase, the variations in the inductance values of the inductor components will increase.

Therefore, an object of the present disclosure is to provide an inductor component that can reduce variations in inductance value even as the thickness of the inductor component increases.

In order to solve the above problems, an inductor component that is one aspect of the present disclosure includes:
Spiral wiring wound on a flat surface,
a first magnetic layer and a second magnetic layer sandwiching the spiral wiring from both sides in the normal direction to the plane around which the spiral wiring is wound;
a vertical wiring extending from the spiral wiring in the normal direction and penetrating the inside of at least the first magnetic layer of the first magnetic layer and the second magnetic layer;
an external terminal provided on the surface of at least the first magnetic layer of the first magnetic layer and the second magnetic layer and covering an end surface of the vertical wiring;
Regarding the area of the external terminal viewed from the normal direction, the first magnetic layer is larger than the second magnetic layer,
When the thickness of the first magnetic layer is A and the thickness of the second magnetic layer is B, A/((A+B)/2) is 0.6 or more and 1.6 or less.

According to the inductor component of the present disclosure, since there is a relative margin between the thickness of the first magnetic layer and the thickness of the second magnetic layer, adjustment is possible by, for example, grinding. Furthermore, as will be described later, the influence on the inductance value is also small.

Therefore, even if the device becomes thinner, variations in inductance values can be reduced. In addition, in this application, "spiral wiring" is a curve formed in a planar shape (two-dimensional curve), and may be a curve with less than one turn, and may have a straight portion in part. Good too.

Moreover, in one embodiment of the inductor component, the thickness of the first magnetic layer is thicker than the thickness of the second magnetic layer.

According to the embodiment, since the first magnetic layer is thicker than the second magnetic layer, it is possible to narrow the deviation of the inductance.

Further, in one embodiment of the inductor component, the thickness of the first magnetic layer and the thickness of the second magnetic layer are each 10 μm or more.

According to the embodiment, since the thickness of the first magnetic layer and the thickness of the second magnetic layer are each 10 μm or more, it is possible to suppress the exposure of the spiral wiring from the first and second magnetic layers.

Further, in one embodiment of the inductor component, the spiral wiring is a conductor made of copper or a copper compound.

According to the embodiment, the DC resistance of the spiral wiring can be reduced.

Further, in one embodiment of the inductor component, the spiral wiring is covered with an insulating resin made of an inorganic filler and an organic resin.

According to the embodiment, insulation can be ensured even if the gap between the spiral wirings is narrow, so that a highly reliable inductor component can be provided.

Further, in one embodiment of the inductor component, the thickness of the inductor component is 0.35 mm or less.

According to the embodiment, it is possible to sufficiently mount the device in applications that require thinness, such as smart cards.

Moreover, in one embodiment of the inductor component, the thickness of the spiral wiring is thicker than (A+B)/2 and thinner than 2(A+B).

According to the embodiment, even if the spiral wiring is made thin, the DC resistance of the spiral wiring can be reduced and the inductance can be ensured.

Further, in one embodiment of the inductor component, the thickness of the inductor component is 0.2 mm or less.

According to the embodiment, even with a thin inductor component, inductance can be ensured while reducing the DC resistance of the spiral wiring.

Also, in one embodiment of the inductor component, the second magnetic layer has a higher magnetic permeability than the first magnetic layer.

According to the embodiment, the inductance acquisition efficiency can be increased.

Further, in one embodiment of the inductor component, the vertical wiring does not exist inside the second magnetic layer.

According to the embodiment, in the second magnetic layer whose magnetic permeability is higher than that of the first magnetic layer, vertical wiring that reduces the volume of the magnetic material is not formed, thereby increasing the inductance acquisition efficiency. Further, since the second magnetic layer is more affected by processing than the first magnetic layer, the yield can be increased by not forming vertical wiring inside the second magnetic layer.

Additionally, in one embodiment of the inductor component,
The first magnetic layer is a composite material of an inorganic filler made of FeSi-based, FeCo-based, FeAl-based alloy, or an amorphous alloy thereof, and an epoxy, polyimide, or phenol-based organic resin,
The content of the inorganic filler is 50 vol % or more based on the organic resin, and the inorganic filler has a substantially spherical shape.

According to the embodiment, the first magnetic layer is a composite material of an inorganic filler and an organic resin, and the content of the inorganic filler is 50 vol% or more, so even if vertical wiring is provided in the first magnetic layer, the magnetic Achieves both properties and workability. Further, since the inorganic filler is approximately spherical, when vertical wiring is provided in the first magnetic layer, the vertical wiring easily slips and is filled into the first magnetic layer.

Further, in one embodiment of the inductor component, the amount of magnetic powder is smaller in at least a portion between the first magnetic layer and the second magnetic layer than in the first magnetic layer and the second magnetic layer. There are fewer areas.

According to the embodiment, since there is a region with a small amount of magnetic powder between the first magnetic layer and the second magnetic layer, the adhesion between the first magnetic layer and the second magnetic layer is improved. , the strength of the magnetic layer of the inductor component can be improved. Alternatively, by providing a region where the amount of magnetic powder present is small, the magnetic saturation characteristics can be improved.

Further, in one embodiment of the inductor component, the thickness of the region is 0.5 μm or more and 30 μm or less.

According to the embodiment, the strength of the magnetic layer of the inductor component can be improved while the inductor component is made thinner, or the magnetic saturation characteristics can be improved.

Additionally, in one embodiment of the inductor component,
There are multiple spiral wirings,
Further comprising a via conductor connecting the spiral wirings in series between the plurality of spiral wirings,
The same layer as the via conductor, which includes the via conductor, contains only a conductor, an inorganic filler, and an organic resin.

According to the above embodiment, the same layer as the via conductor does not include a base material such as glass cloth that requires a certain thickness, so while it is possible to reduce the thickness, the portion that does not contribute to electrical characteristics is relatively reduced. By doing so, the electrical characteristics can be improved even if the thickness is the same.

Further, in one embodiment of the inductor component, the thickness of the same layer as the via conductor is 1 μm or more and 20 μm or less.

According to the embodiment, since the thickness of the same layer as the via conductor is 1 μm or more, short circuits between spiral wiring can be reliably prevented, and the thickness of the same layer as the via conductor is 20 μm or less, We can provide thin inductor parts.

In one embodiment of the inductor component, the inorganic filler is made of at least one of a FeSi alloy, a FeCo alloy, a FeAl alloy, an amorphous alloy thereof, and _SiO2 , and the inorganic filler has an average particle size of: It is 5 μm or less.

According to the embodiment, it is possible to reduce loss at high frequencies and ensure insulation.

According to an inductor component that is one aspect of the present disclosure, even if the inductor component becomes thinner, variations in inductance values can be reduced.

FIG. 2 is a perspective plan view showing an inductor component according to the first embodiment. FIG. 2 is a sectional view showing an inductor component according to the first embodiment. There is a graph showing the first simulation results of the inductor component according to the first embodiment. There is a graph showing a second simulation result of the inductor component according to the first embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. It is an explanatory view explaining the manufacturing method of the inductor component concerning a 1st embodiment. FIG. 7 is a cross-sectional view showing an inductor component according to a second embodiment. FIG. 7 is an enlarged cross-sectional view showing an inductor component according to a second embodiment. FIG. 7 is a perspective plan view showing an inductor component according to a third embodiment. FIG. 7 is a cross-sectional view showing an inductor component according to a third embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment. It is an explanatory view explaining a manufacturing method of an inductor component concerning a 3rd embodiment.

Hereinafter, one aspect of the present disclosure will be described in detail with reference to illustrated embodiments.

(First embodiment)
(composition)
FIG. 1 is a perspective plan view showing a first embodiment of an inductor component. FIG. 2 is a sectional view taken along line XX in FIG.

The inductor component 1 is mounted in electronic equipment such as a personal computer, a DVD player, a digital camera, a TV, a mobile phone, and a car electronics, and is, for example, a rectangular parallelepiped-shaped component as a whole. However, the shape of the inductor component 1 is not particularly limited, and may be a cylinder, a polygonal column, a truncated cone, or a truncated polygon.

As shown in FIGS. 1 and 2, the inductor component 1 includes a magnetic layer 10, an insulating layer 15, a spiral wiring 21, vertical wirings 51 to 53, external terminals 41 to 43, and a coating film 50. have

The spiral wiring 21 is made of a conductive material and is wound on a plane. The normal direction to the plane around which the spiral wiring 21 is wound is the Z direction (vertical direction) in the figure, and hereinafter, the forward Z direction will be referred to as the upper side and the reverse Z direction will be referred to as the lower side. Note that the Z direction is the same in other embodiments and examples. The spiral wiring 21 is spirally wound in a clockwise direction from an inner circumferential end 21a toward an outer circumferential end 21b when viewed from above.

The magnetic layer 10 is made of a magnetic material and includes a first magnetic layer 11 , a second magnetic layer 12 , an inner magnetic path section 13 , and an outer magnetic path section 14 . The first magnetic layer 11 and the second magnetic layer 12 are located at positions sandwiching the spiral wiring 21 from both sides in the Z direction (the normal direction to the plane on which the spiral wiring 21 is wound). Specifically, the first magnetic layer 11 is located above the spiral wiring 21 and the second magnetic layer 12 is located below the spiral wiring 21. As shown in FIG. 1, the inner magnetic path section 13 and the outer magnetic path section 14 are arranged inside and outside the spiral wiring 21, respectively, and as shown in FIG. It is connected to the. In this way, the magnetic layer 10 forms a closed magnetic path with respect to the spiral wiring 21. Although the first magnetic layer 11, the second magnetic layer 12, the inner magnetic path section 13, and the outer magnetic path section 14 are drawn separately in the figure, they may be integrated as the magnetic layer 10.

The insulating layer 15 is made of an insulating material and is disposed between the first magnetic layer 11 and the second magnetic layer 12, and the spiral wiring 21 is embedded in the insulating layer 15. The insulating layer 15 is an insulating resin made of an inorganic filler and an organic resin. By covering the spiral wiring 21 with the insulating layer 15, insulation can be ensured even if the gap between the spiral wirings 21 is narrow, so that a highly reliable inductor component can be provided. Although FIG. 1 shows the magnetic layer 10 and the insulating layer 15 as transparent, the magnetic layer 10 and the insulating layer 15 may be transparent, translucent, or opaque, or may be colored. You can.

The vertical wirings 51 to 53 are made of a conductive material, extend from the spiral wiring 21 in the Z direction, and penetrate inside the first magnetic layer 11 or the second magnetic layer 12. The vertical wirings 51 to 53 include a via conductor 25 extending from the spiral wiring 21 in the Z direction and penetrating the inside of the insulating layer 15, and a via conductor 25 extending from the via conductor 25 in the Z direction and connecting to the first magnetic layer 11 or the second magnetic layer 11. It includes columnar wirings 31 to 33 that penetrate inside the magnetic layer 12.

The first vertical wiring 51 includes a via conductor 25 extending upward from the upper surface of the inner circumferential end 21a of the spiral wiring 21, and a via conductor 25 extending upward from the via conductor 25 and penetrating the inside of the first magnetic layer 11. 1 columnar wiring 31. The second vertical wiring 52 and the third vertical wiring 53 are present on both sides of the spiral wiring 21 in the Z direction. The second vertical wiring 52 includes a via conductor 25 extending upward from the upper surface of the outer peripheral end 21 b of the spiral wiring 21 , and a second vertical wiring 52 extending upward from the via conductor 25 and penetrating the inside of the first magnetic layer 11 . The columnar wiring 32 is included. The third vertical wiring 53 includes a via conductor 25 extending downward from the lower surface of the outer circumferential end 21b of the spiral wiring 21, and a via conductor 25 extending downward from the via conductor 25 and penetrating the inside of the second magnetic layer 12. and a third columnar wiring 33.

The external terminals 41 to 43 are made of a conductive material and are provided on the surfaces of the first magnetic layer 11 and the second magnetic layer 12. The external terminals 41 to 43 cover the end faces of the vertical wirings 51 to 53, respectively. Note that the "surface" refers to the main surface facing outside of the inductor component 1, the surface of the first magnetic layer 11 is the top surface, and the surface of the second magnetic layer 12 is the bottom surface. The first external terminal 41 is provided on the upper surface of the first magnetic layer 11 and covers the end surface of the vertical wiring 51 (first columnar wiring 31) exposed from the upper surface. The second external terminal 42 and the third external terminal 43 are present on both sides of the spiral wiring 21 in the Z direction. The second external terminal 42 is provided on the upper surface of the first magnetic layer 11 and covers the end surface of the vertical wiring 52 (second columnar wiring 32) exposed from the upper surface. The third external terminal 43 is provided on the lower surface of the second magnetic layer 12 and covers the end surface of the vertical wiring 53 (third columnar wiring 33) exposed from the lower surface.

Preferably, the external terminals 41 to 43 are subjected to anti-rust treatment. Here, the rust prevention treatment means coating with Ni and Au, or Ni and Sn, or the like. Thereby, copper eating by solder and rust can be suppressed, and an inductor component 1 with high mounting reliability can be provided.

The coating film 50 is made of an insulating material, and covers the upper surface of the first magnetic layer 11 and the lower surface of the second magnetic layer 12, as shown in FIG. is exposed. In addition, in FIG. 1, the coating film 50 is omitted.

The first magnetic layer 11 is larger than the second magnetic layer 12 in terms of the area of the external terminals 41 to 43 when viewed from the normal direction (Z direction). Specifically, the total area of the external terminals 41 and 42 provided on the surface of the first magnetic layer 11 is larger than the total area of the external terminals 43 provided on the surface of the second magnetic layer 12. Note that the external terminal may be provided only in the first magnetic layer 11 of the first magnetic layer 11 and the second magnetic layer 12, and in this case, the first magnetic layer 11 naturally has the area of the external terminal. 2 magnetic layers 12.

When the thickness of the first magnetic layer 11 is A and the thickness of the second magnetic layer 12 is B, A/((A+B)/2) is 0.6 or more and 1.6 or less. According to this, since there is a relative margin between the thickness of the first magnetic layer 11 and the thickness of the second magnetic layer 12, adjustment is possible by, for example, grinding. Moreover, the influence on the inductance value is also small. Therefore, even if the device becomes thinner, variations in inductance values can be reduced.

At this time, the thickness of the inductor component 1 is preferably 0.35 mm or less. Therefore, it can be fully installed in applications that require thinness, such as smart cards.

Further, the thickness of the first magnetic layer 11 is preferably thicker than the thickness of the second magnetic layer 12. Therefore, when the external terminals 41 and 42 on the first magnetic layer 11 side are connected to the land pattern of the mounting board, leakage of magnetic flux to the land pattern is reduced, eddy current is reduced within the conductor of the land pattern, and eddy current It is possible to suppress the decrease in inductance due to

Further, the thickness of the spiral wiring 21 is preferably thicker than (A+B)/2 and thinner than 2(A+B). Therefore, even if the spiral wiring 21 is made thin, the DC resistance of the spiral wiring 21 can be reduced and the inductance can be ensured. Specifically, in a power inductor used for a converter, when the DC resistance increases, the power loss of the converter increases, leading to a decrease in efficiency, so it is necessary to increase the cross-sectional area of the spiral wiring 21. be. In other words, it is desirable that the spiral wiring 21 be sufficiently thick. On the other hand, if the thickness of the spiral wiring 21 is made too thick, in the case of a thin inductor component 1, the required thickness of the magnetic layers 11 and 12 cannot be secured in order to secure sufficient inductance. This is not preferable, but by forming within this range, desired characteristics can be easily obtained when a thin inductor component 1 is assumed.

At this time, the thickness of the inductor component 1 is preferably 0.2 mm or less. Therefore, even with the thin inductor component 1, inductance can be ensured while reducing the DC resistance of the spiral wiring 21.

According to the inductor component 1, the vertical wirings 51 to 53 extend from the spiral wiring 21 in the Z direction and penetrate inside the first magnetic layer 11 or the second magnetic layer 12. More specifically, the vertical wirings 51 to 53 include a via conductor 25 extending from the spiral wiring 21 in the Z direction and penetrating the inside of the insulating layer 15, and a first conductor extending from the via conductor 25 in the Z direction. Columnar wirings 31 to 33 that penetrate inside the magnetic layer 11 or the second magnetic layer 12 are included.

That is, in the inductor component 1, the wiring is directly drawn out from the spiral wiring 21 in the Z direction. This means that the spiral wiring 21 is drawn out to the top or bottom side of the inductor component over the shortest distance, and in three-dimensional mounting where the board wiring is connected from the top or bottom side of the inductor component 1, This means that unnecessary wiring can be reduced. Therefore, the inductor component 1 has a configuration that can sufficiently accommodate three-dimensional mounting, and the degree of freedom in circuit design can be improved.

Further, in the inductor component 1, since no wiring is drawn out from the spiral wiring 21 in the side direction, the area of the inductor component 1 viewed from the Z direction, that is, the mounting area can be reduced. Therefore, the inductor component 1 can achieve a reduction in the mounting area required for both surface mounting and three-dimensional mounting, and can improve the degree of freedom in circuit design.

Furthermore, in the inductor component 1, the columnar wires 31 to 33 penetrate inside the magnetic layer 10 and extend in the normal direction to the plane around which the spiral wire 21 is wound. In this case, in the columnar wirings 31 to 33, current does not flow in the direction along the plane around which the spiral wiring 21 is wound, but in the Z direction.

Here, as the size of the inductor component 1 becomes smaller, the magnetic layer 10 also becomes relatively smaller, but the magnetic flux density becomes higher, especially in the inner magnetic path section 13, and magnetic saturation becomes more likely. However, since the magnetic flux caused by the Z-direction current flowing through the columnar wirings 31 to 33 does not pass through the inner magnetic path section 13, the influence on the magnetic saturation characteristics, that is, the DC superimposition characteristics can be reduced. On the other hand, when the wire is pulled out from the spiral wiring to the side (direction along the plane on which the spiral wiring is wound) by the lead-out part as in the conventional technology, the magnetic flux generated by the current flowing in the lead-out part is Since a part of it passes through the inner magnetic path section and the outer magnetic path section, it is impossible to avoid the influence on the magnetic saturation characteristics and DC superposition characteristics.

Note that since the columnar wirings 31 to 33 penetrate through the inside of the first magnetic layer 11 or the second magnetic layer 12, the opening in the magnetic layer 10 can be made small when the wiring is drawn out from the spiral wiring 21. It can have a closed magnetic circuit structure. Thereby, noise propagation to the substrate side can be suppressed.

Furthermore, in the inductor component 1, the vertical wires 51 to 53 are located on both sides of the spiral wire 21 in the Z direction, so that the wires can be drawn out to both sides of the spiral wire 21 in the Z direction. . Specifically, for example, in the inductor component 1, the external terminals 41 to 43 are located on both sides of the spiral wiring 21 in the Z direction. In this case, for example, it is possible to expand the options for connecting the board wiring, which is suitable for three-dimensional mounting in which the board wiring can be connected from the top and bottom sides of the inductor component 1.

Furthermore, since the spiral wiring 21 is wound on a plane along the magnetic layer 10, the inner magnetic path portion 13 can be made large even when the thickness is reduced, and the thin inductor component 1 has high magnetic saturation characteristics. can be provided. On the other hand, for example, if an inductor component in which spiral wiring is wound perpendicularly to the plane along the magnetic layer 10 is used, it is possible to further reduce the thickness of the inductor component, that is, to reduce the thickness of the inductor component in the thickness direction of the substrate. , the coil diameter = the area of the magnetic layer is reduced. As a result, magnetic saturation characteristics deteriorate, and sufficient current cannot be applied to the inductor.

Note that the vertical wirings 51 to 53 and the external terminals 41 to 43 may be formed only in the first magnetic layer 11. Further, a dummy terminal may be provided as an external terminal provided on the surface of the first magnetic layer 11 or the second magnetic layer 12 and not electrically connected to the spiral wiring 21. Since the dummy terminal is electrically conductive, that is, has high thermal conductivity, heat dissipation is improved, and a highly reliable (highly environmentally resistant) inductor component 1 can be provided. For example, when the dummy terminal is connected to the board wiring of a board (including an embedded board), a heat dissipation path is formed from the dummy terminal through the board wiring, so that the heat dissipation performance is further improved. In addition, if the dummy terminal is grounded, for example, if the dummy terminal is connected to the ground wire of the board wiring, the dummy terminal forms an electrostatic shield to prevent static electricity from propagating to the external circuit. This can prevent malfunctions caused by noise. Furthermore, when the inductor component 1 is surface mounted, the dummy terminal can be used to stabilize the posture of the inductor component 1.

Furthermore, as shown in FIG. 2, the inductor component 1 includes a coating film 50 that covers the surface of the first magnetic layer 11 or the second magnetic layer 12 and exposes the end faces of the vertical wirings 51 to 53. Here, the above-mentioned "exposure" includes not only the outward exposure of the inductor component 1 but also the exposure to other members.

Specifically, the coating film 50 covers the upper surface of the first magnetic layer 11 except for the external terminals 41 and 42. The coating film 50 covers the lower surface of the second magnetic layer 12 except for the external terminals 43 . In this way, the end surfaces of the vertical wirings 51 to 53 connected to the external terminals 41 to 43 are exposed from the coating film 50. Therefore, insulation between adjacent external terminals 41 and 42 (vertical wirings 51 and 52) can be ensured. Thereby, the pressure resistance and environment resistance of the inductor component 1 can be ensured. Furthermore, depending on the shape of the coating film 50, the formation area of the external terminals 41 to 43 formed on the surface of the magnetic layer 10 can be arbitrarily set, which increases the degree of freedom during mounting. External terminals 41 to 43 can be easily formed.

Note that in the inductor component 1, as shown in FIG. 2, the surfaces of the external terminals 41 to 43 are located on the outer side in the Z direction than the surfaces of the first magnetic layer 11 or the second magnetic layer 12. Specifically, the external terminals 41 to 43 are embedded in the coating film 50, and the surfaces of the external terminals 41 to 43 are flush with the surface of the first magnetic layer 11 or the second magnetic layer 12. do not have. At this time, the positional relationship between the surface of the magnetic layer 10 and the surfaces of the external terminals 41 to 43 can be set independently, and the degree of freedom in the thickness of the external terminals 41 to 43 can be increased. According to this configuration, the height position of the surface of the external terminals 41 to 43 in the inductor component 1 can be adjusted. For example, when the inductor component 1 is embedded in a board, the height position of the surface of the external terminals of other embedded components can be adjusted. It is possible to match the height position. Therefore, by using the inductor component 1, it is possible to streamline the laser focusing process when forming vias on the substrate, and it is possible to improve the manufacturing efficiency of the substrate.

Furthermore, in the inductor component 1, as shown in FIG. It is larger than the area of the columnar wirings 31 to 33). Therefore, the bonding area during mounting is increased, and the mounting reliability of the inductor component 1 is improved. Further, when mounting on a board, an alignment margin can be secured for the bonding position between the board wiring and the inductor component 1, and mounting reliability can be improved. At this time, since mounting reliability can be improved regardless of the volume of the columnar wirings 31 to 33, by reducing the cross-sectional area of the columnar wirings 31 to 33 when viewed from the Z direction, the first magnetic layer 11 or the A decrease in the volume of the second magnetic layer 12 can be suppressed, and a deterioration in the characteristics of the inductor component 1 can be suppressed.

The spiral wiring 21, the vertical wirings 51 to 53 (the via conductor 25, the columnar wirings 31 to 33), and the external terminals 41 to 43 are preferably conductors made of copper or a copper compound. Thereby, it is possible to provide an inductor component 1 that is inexpensive and can reduce direct current resistance. Furthermore, by using copper as the main material, it is possible to improve the bonding strength and conductivity between the spiral wiring 21, the vertical wirings 51 to 53, and the external terminals 41 to 43.

Note that the inductor component 1 includes an insulating layer 15 that is disposed between the first magnetic layer 11 and the second magnetic layer 12 and in which the spiral wiring 21 is embedded. As a result, in the inductor component 1, even if the space between the wires is very narrow, it is possible to eliminate the possibility of creating an electrical short circuit path between the wires through magnetic materials such as metal magnetic bodies. Highly reliable inductor parts can be provided. However, the insulating layer 15 may be a part of the magnetic layer 10 by being made of a magnetic material. When the insulating layer 15 is a part of the magnetic layer 10, the volume of the magnetic layer 10 increases when considering the same chip size, so that the inductance value can be increased. Note that in this case, the vertical wirings 51 to 53 may have a structure in which the via conductor 25 and the columnar wirings 31 to 33 are integrated and are not distinguished from each other.

Although the inductor component 1 has one spiral wiring, it is not limited to this configuration, and may include two or more spiral wiring wound on the same plane.

However, since the inductor component 1 has a high degree of freedom in forming the external terminals 41 to 43, this effect becomes even more pronounced in an inductor component with a large number of external terminals.

(Example)
Next, an example of the inductor component 1 will be described.

The spiral wiring 21, the vertical wirings 51 to 53 (the via conductors 25, the columnar wirings 31 to 33), and the external terminals 41 to 43 are made of a low resistance metal such as Cu, Ag, or Au. Preferably, by using copper plating formed by SAP (Semi Additive Process), the spiral wiring 21 with low resistance and narrow pitch can be formed at low cost. Note that the spiral wiring 21, the vertical wirings 51 to 53, and the external terminals 41 to 43 may be formed by a plating method other than SAP, such as a sputtering method, a vapor deposition method, or a coating method.

In this embodiment, the spiral wiring 21 and the vertical wirings 51 to 53 are formed by SAP copper plating, and the external terminals 41 to 43 are formed by electroless Cu plating. Note that the spiral wiring 21, the vertical wirings 51 to 53 (the via conductors 25, the columnar wirings 31 to 33), and the external terminals 41 to 43 may all be formed by the same method.

The magnetic layer 10 (the first magnetic layer 11, the second magnetic layer 12, the inner magnetic path section 13, and the outer magnetic path section 14) is made of, for example, a resin containing powder of a magnetic material, and is preferably made of approximately spherical metal. Contains magnetic materials. Therefore, the filling property of the magnetic path of the magnetic material can be improved. Thereby, the magnetic path can be made small, and a compact inductor component 1 can be provided. However, the magnetic layer may be a resin containing powder of a magnetic material such as ferrite, or may be a sintered ferrite substrate or a green sheet of a magnetic material.

In this embodiment, the resin constituting the magnetic layer 10 is an organic insulating material made of, for example, epoxy resin, bismaleimide, liquid crystal polymer, or polyimide. Further, the magnetic material powder of the magnetic layer 10 is a metallic magnetic substance with an average particle size of 5 μm or less. The metal magnetic material is, for example, a FeSi-based alloy such as FeSiCr, a FeCo-based alloy, a Fe-based alloy such as NiFe, or an amorphous alloy thereof. The content of the magnetic material is preferably 50 vol% or more and 85 vol% or less based on the entire magnetic layer 10.

As mentioned above, by using a magnetic material with a small average particle size of 5 μm or less, it is possible to suppress the eddy current generated in the metal magnetic material, and the inductor component 1 has low loss even at high frequencies of several tens of MHz. can be obtained.

Furthermore, by using an Fe-based magnetic material, it is possible to obtain greater magnetic saturation characteristics than ferrite or the like.

In addition, by increasing the filling amount of magnetic material to 50 vol% or more, magnetic permeability can be increased, and the number of turns of spiral wiring required to obtain the desired inductance value can be reduced. loss can be reduced. Furthermore, when the filling amount is 85 vol% or less, the volume of the organic insulating resin is sufficiently large compared to the magnetic material, and the fluidity of the magnetic material can be ensured, so the filling property is improved and the effective magnetic permeability and the magnetic material itself are improved. Strength can be improved.

On the other hand, when used at low frequencies, there is no need to be concerned about eddy current loss as it is at high frequencies, so the average particle size of the metal magnetic material may be increased to provide higher magnetic permeability. For example, it is preferable to use a magnetic material in which large particles with an average particle size of 100 to 30 μm and some small particles (10 μm or less) coexist so as to fill the gaps between the large particles. By doing so, the filling amount can be increased and a magnetic material with high magnetic permeability at frequencies such as 1 to 10 MHz can be realized. However, at frequencies of 1 MHz or higher, the relative magnetic permeability is preferably 70 or lower in order to suppress the influence of eddy current loss.

In this embodiment, the coating film 50 is formed of a photosensitive resist or solder resist made of an organic insulating resin such as polyimide, phenol, or epoxy resin.

Further, the rust prevention treatment applied to the surfaces of the external terminals 41 to 43 is plating with Ni, Au, Sn, or the like.

The insulating layer 15 is made of, for example, a resin containing SiO ₂ filler with an average particle size of 0.5 μm or less. However, the filler is not an essential component in the insulating layer 15. The area around the spiral wiring 21 is covered with an insulating layer 15 as in this embodiment, so that the spiral wiring 21 and the magnetic material do not come into contact with each other. However, since the magnetic material itself has insulation properties, insulation is not necessarily required. It is not necessary to coat with layer 15.

When not covered with the insulating layer 15, the inductance value can be increased by increasing the volume of the magnetic material considering the same chip size. On the other hand, when the spiral wiring 21 is covered with the insulating layer 15 as in this embodiment, if the space between the spiral wiring 21 is very narrow, an electrical short-circuit may occur between the spiral wiring 21 via the metal magnetic material. The possibility of a path being formed can be eliminated, and a highly reliable inductor component 1 can be provided.

In this embodiment, the spiral wiring 21 has a wiring width of 60 μm, an inter-wire space of 10 μm, and a wiring thickness of 70 μm.

Note that the space between wirings is preferably 20 μm or less and 3 μm or more. By setting the inter-wiring space to 20 μm or less, the wiring width can be increased, and the direct current resistance can be lowered. By setting the space between the wires to 3 μm or more, sufficient insulation between the wires can be maintained.

Moreover, the wiring thickness is preferably 40 μm or more and 120 μm or less. By setting the wiring thickness to 40 μm or more, the direct current resistance can be sufficiently lowered. By setting the wiring thickness to 120 μm or less, the wiring aspect does not become extremely large, and process variations can be suppressed.

The thickness of the insulating layer 15 between the spiral wiring 21 and the first magnetic layer 11 and between the spiral wiring 21 and the second magnetic layer 12 is 10 μm. The thickness of one insulating layer 15 is 25 μm.

Note that the width of the insulating layer 15 between the spiral wiring 21 and the first magnetic layer 11 and the second magnetic layer 12 is preferably 3 μm or more and 20 μm or less. By setting a distance of 3 μm or more, it is possible to reliably prevent the spiral wiring 21 from coming into contact with the first magnetic layer 11 and the second magnetic layer 12, and by setting the distance to 20 μm or less, the inductor component 1 can be made thinner.

The width of the insulating layer 15 between the inner magnetic path portion 13 and the spiral wiring 21 is preferably 3 μm or more and 50 μm or less. By setting a distance of 3 μm or more, it is possible to reliably prevent the spiral wiring 21 and the inner magnetic path portion 13 from coming into contact with each other, and by setting the distance to 45 μm or less, the inner magnetic path portion 13 or the outer magnetic path portion 14 can be made wider. Therefore, the magnetic saturation characteristics can be improved and the inductance value can be increased.

In this embodiment, the number of turns of the spiral wiring 21 is 2.5 turns. The number of turns is preferably 5 turns or less. If the number of turns is 5 or less, the loss due to the proximity effect can be reduced for high frequency switching operations from 50 MHz to 150 MHz. On the other hand, when used in low frequency switching operation such as 1 MHz, 2.5 turns or more is preferable. By increasing the number of turns, the inductance can be increased and the inductor ripple current can be reduced.

In this embodiment, the thickness of the first magnetic layer 11 is 117.5 μm, and the thickness of the second magnetic layer 12 is 67.5 μm. The thickness of the first magnetic layer 11 and the second magnetic layer 12 is preferably 10 μm or more and 200 μm or less, respectively. If the thickness of the first and second magnetic layers 11 and 12 is too thin, the spiral wiring 21 may be exposed due to process variations during grinding of the first and second magnetic layers 11 and 12. Further, when the thickness of the first and second magnetic layers 11 and 12 is thinner than the average grain size of the magnetic material contained in the first and second magnetic layers 11 and 12, the effective magnetic permeability decreases significantly due to grain shedding. By setting the thickness of the first and second magnetic layers 11 and 12 to 200 μm or less, the inductor component can be made thinner.

Further, as in the present embodiment, the thicknesses of the first and second magnetic layers 11 and 12 may be different, and the thickness of the first magnetic layer 11 having a large external terminal area is A, and the thickness of the second magnetic layer 12 is A. When B is, (A/(A+B)/2) is preferably in the range of 0.6 to 1.6.

At this time, since there is a relative margin between the thickness of the first magnetic layer 11 and the thickness of the second magnetic layer 12, adjustment is also possible by, for example, grinding. Furthermore, as will be described later, the influence on the inductance value is also small. Further, since there is a relatively large margin in the correlation between the thicknesses of the first and second magnetic layers 11 and 12, it is possible to have a narrow deviation in the thickness of the inductor component 1. Specifically, since there is a high degree of freedom in setting the thicknesses of the first and second magnetic layers 11 and 12, it is possible to avoid thickness variations caused by processing, such as variations in the thickness of the spiral wiring 21 and the thickness of the insulating layer 15. Variations can be absorbed by the thickness of the magnetic layers 11 and 12, and as a result, the thickness deviation of the inductor component 1 can be narrowed.

Further, the thickness of the first magnetic layer 11 is preferably thicker than the thickness of the second magnetic layer 12. In the inductor component 1, the first magnetic layer 11 is larger than the second magnetic layer 12 in terms of the area of the external terminals 41 to 43 when viewed from the normal direction (Z direction). That is, in the inductor component 1, the magnetic flux in the first magnetic layer 11 is more easily blocked by the external terminals 41 to 43 than the magnetic flux in the second magnetic layer 12. Therefore, by increasing the thickness on the first magnetic layer 11 side and increasing the distance from the external terminals 41 to 43 to reduce the influence of the external terminals 41 to 43, it is possible to reduce the variation in the magnetic layer thickness (chip thickness) of the inductance. It is possible to reduce sensitivity and provide an inductor component having inductance with narrow deviation. Furthermore, in general, the area of the land pattern on the side of the substrate on which the inductor component 1 is mounted and built-in is larger on the first magnetic layer 11 side, where the area of the external terminals 41 to 43 is larger, and the number of surrounding electronic components is also larger. Cheap. Therefore, by increasing the thickness of the first magnetic layer 11 to reduce magnetic flux leakage, it is possible to effectively reduce the negative effects of magnetic flux leakage, such as eddy current loss due to the land pattern and noise input to surrounding electronic components. Can be done.

The thickness of the external terminals 41 to 43 including anti-rust treatment is 5 μm thick for electroless copper plating, 5 μm thick for Ni plating, and 0.1 μm thick for Au plating. Further, the thickness of the coating film 50 is 5 μm. These thicknesses and sizes may be selected from the viewpoint of convenient chip thickness and mounting reliability.

As described above, according to this embodiment, a thin inductor having a chip size of 1210 (1.2 mm x 1.0 mm) and a thickness of 0.300 mm can be provided.

(simulation result)
Below, the results of a simulation based on the configuration of the inductor component 1, which was conducted to demonstrate the effects of the configuration of the inductor component 1, will be explained. FIG. 3A shows the first simulation results. FIG. 3A shows the relationship between (A/(A+B)/2) and the change in inductance (ΔL) when the chip thickness is changed. The simulation conditions will be explained. The electromagnetic field simulator HFSS@Synopsys is used as a simulator. The magnetic permeability μ of the magnetic material is 8.9, the L acquisition frequency is 100 MHz, the chip size is 1.2 mm x 1.0 mm, and the number of turns of the spiral wiring 21 is 2.5 turns. The spiral wiring L/S/t is 60 μm/10 μm/70 μm. Graph L1 shows when the chip thickness is 0.200 mm, and graph L2 shows when the chip thickness is 0.300 mm. As shown in FIG. 3A, when (A/(A+B)/2) is in the range of 0.6 to 1.6, the change in inductance can be suppressed to a decrease of 10%.

FIG. 3B shows the second simulation result. FIG. 3B shows the relationship between (A/(A+B)/2) and the change in inductance (ΔL) when the magnetic permeability of the magnetic material is changed. The simulation conditions will be explained. The electromagnetic field simulator HFSS@Synopsys is used as a simulator. The L acquisition frequency is 100 MHz, the chip size is 1.2 mm x 1.0 mm, the chip thickness is 0.200 mm, the number of turns of the spiral wiring 21 is 2.5 turns, and the spiral wiring L/ S/t is 60 μm/10 μm/70 μm. Graph L1 shows when the magnetic permeability μ of the magnetic material is 8.6, graph L2 shows when the magnetic permeability μ of the magnetic material is 26.5, and the magnetic permeability μ of the magnetic material is 70. The time is shown in graph L3. As shown in FIG. 3B, when (A/(A+B)/2) is in the range of 0.6 to 1.6, the change in inductance can be suppressed to a decrease of 20%.

(Production method)
Next, a method for manufacturing the inductor component 1 will be described.

A dummy core substrate 61 is prepared as shown in FIG. 4A. Both sides of the dummy core board 61 have substrate copper foil. In this embodiment, the dummy core substrate 61 is a glass epoxy substrate. Since the thickness of the dummy core substrate 61 does not affect the thickness of the inductor component, it is sufficient to use a thickness that is easy to handle for reasons such as warping during processing.

Next, a copper foil 62 is bonded onto the surface of the substrate copper foil. Copper foil 62 is adhered to the smooth surface of the substrate copper foil. Therefore, the adhesive force between the copper foil 62 and the substrate copper foil can be weakened, and the dummy core substrate 61 can be easily peeled off from the copper foil 62 in a subsequent process. Preferably, the adhesive for bonding the dummy core substrate 61 and the dummy metal layer (copper foil 62) is a low adhesive agent. Further, in order to weaken the adhesive force between the dummy core substrate 61 and the copper foil 62, it is desirable that the bonding surface between the dummy core substrate 61 and the copper foil 62 be a glossy surface.

After that, an insulating layer 63 is laminated on the copper foil 62. At this time, the insulating layer 63 is thermally pressed and hardened using a vacuum laminator, a press machine, or the like.

As shown in FIG. 4B, an opening 63a is formed in the insulating layer 63 by laser processing or the like. Then, as shown in FIG. 4C, a dummy copper 64a and a spiral wiring 64b are formed on the insulating layer 63. Specifically, a power supply film (not shown) for SAP is formed on the insulating layer 63 by electroless plating, sputtering, vapor deposition, or the like. After forming the power supply film, a photosensitive resist is applied or pasted onto the power supply film, and openings in the photosensitive resist are formed at locations that will become wiring patterns by photolithography. After that, a dummy copper 64a and a metal wiring corresponding to the spiral wiring 64b are formed in the opening of the photosensitive resist layer. After forming the metal wiring, the photosensitive resist is removed using a chemical solution, and the power supply film is removed by etching. Thereafter, this metal wiring is used as a power supply section and additional copper electrolytic plating is applied to obtain wiring in a narrow space. Further, the opening 63a formed by SAP in FIG. 4B is filled with copper.

Then, as shown in FIG. 4D, the dummy copper 64a and the spiral wiring 64b are covered with an insulating layer 65. The insulating layer 65 is thermally pressed and hardened using a vacuum laminator, press machine, or the like.

Next, as shown in FIG. 4E, an opening 65a is formed in the insulating layer 65 by laser processing or the like.

Thereafter, the dummy core substrate 61 is peeled off from the copper foil 62. Then, the copper foil 62 is removed by etching or the like, and the dummy copper 64a is removed by etching or the like to form a hole 66a corresponding to the inner magnetic path section 13 and a hole corresponding to the outer magnetic path section 14, as shown in FIG. 4F. 66b.

Thereafter, as shown in FIG. 4G, an insulating layer opening 67a is formed by laser processing or the like. Then, as shown in FIG. 4H, the insulating layer opening 67a is filled with copper using SAP, and the columnar wiring 68 is formed on the insulating layer 67.

Next, as shown in FIG. 4I, the spiral wiring, the insulating layer, and the columnar wiring are covered with a magnetic material (magnetic layer) 69 to form an inductor substrate. The magnetic material 69 is thermally pressed and hardened using a vacuum laminator, press machine, or the like. At this time, the magnetic material 69 is also filled in the holes 66a and 66b.

Then, as shown in FIG. 4J, the magnetic material 69 on the top and bottom of the inductor substrate is thinned by a grinding method. At this time, by exposing a portion of the columnar wiring 68, an exposed portion of the columnar wiring 68 is formed on the same plane of the magnetic material 69. At this time, by grinding the magnetic material 69 to a thickness sufficient to obtain an inductance value, the inductor component can be made thinner.

Thereafter, as shown in FIG. 4K, an insulating resin (coating film) 70 is formed on the surface of the magnetic material by a printing method. Here, the opening 70a of the insulating resin 70 is used as a portion where an external terminal is formed. In this embodiment, a printing method is used, but the opening 70a may be formed using a photolithography method.

Next, as shown in FIG. 4L, an external terminal 71a is formed by electroless copper plating or a plating film such as Ni and Au, and as shown in FIG. 4M, it is diced into pieces at the broken line L, The inductor component shown in FIG. 2 is obtained. Although not shown in FIG. 4B and subsequent figures, inductor substrates may be formed on both sides of the dummy core substrate 61. Thereby, high productivity can be obtained.

In this embodiment, an external terminal is also provided on the second magnetic layer 12 side, but if no external terminal is provided on the second magnetic layer 12 side, as shown in FIG. 4K, the lower surface of the magnetic material 69 is Insulating resin 70 is not provided.

(Second embodiment)
FIG. 5 is a cross-sectional view of the inductor component. The second embodiment differs from the first embodiment in the configuration of the second magnetic layer. This different configuration will be explained below. Note that in the second embodiment, the same reference numerals as those in the first embodiment have the same configurations as in the first embodiment, so the description thereof will be omitted.

As shown in FIG. 5, in the inductor component 1A, the magnetic permeability of the second magnetic layer 12A is higher than the magnetic permeability of the first magnetic layer 11. Therefore, the efficiency of acquiring inductance can be increased. At this time, the thickness A of the first magnetic layer 11 is preferably thicker than the thickness B of the second magnetic layer 12A. As a result, even if the thickness B of the second magnetic layer 12A is small, the magnetic permeability of the second magnetic layer 12A is high, making it difficult to generate leakage flux.Furthermore, since the thickness of the first magnetic layer 11 is thick, Leakage flux on the magnetic layer 11 side is also less likely to occur.

Here, a method for analyzing magnetic permeability will be described. The magnitude of magnetic permeability can be evaluated by the following first, second, or third analysis method. Basically, the first or second analysis method is used for measurement, but only when the first or second analysis method cannot be used, the third analysis method is used for measurement.

As a first analysis method, if the magnetic material is available in liquid form, sheet form, etc., it can be processed into a sheet, plate, or block shape, and the magnetic permeability can be obtained by a known impedance measurement method.

As a second analysis method, from the chip state, for example, after measuring the inductance of the chip, one surface of the magnetic layer is removed by grinding or etching, and the inductance is measured again. Thereafter, it is possible to compare the magnetic permeability from the chip state by determining the effective magnetic permeability that becomes the inductance corresponding to each state using electromagnetic field simulation (for example, HFSS from Ansys).

As a third analysis method, judgment can be made from the cross section of the SEM image based on general and well-known knowledge. For example, from the results of EDX analysis, if magnetic powders of the same material type are used, a magnetic material with a large amount of magnetic powder having a large particle size has a higher magnetic permeability than a magnetic material with a smaller amount of magnetic powder. Here, the SEM image to be acquired may be obtained from a cross section obtained by cutting the center of the longitudinal side of the chip. Further, the magnification of the SEM image is preferably 200 to 2000 times.

Further, the vertical wirings 51 and 52 do not exist inside the second magnetic layer 12A. In this case, in the second magnetic layer 12A whose magnetic permeability is higher than that of the first magnetic layer 11, the inductance acquisition efficiency is increased by not forming a vertical wiring that reduces the volume of the magnetic material. In addition, since the second magnetic layer 12A has a higher magnetic permeability than the first magnetic layer 11, the proportion (volume) of the magnetic material in the magnetic layer is large, and the magnetic material is easily shed or chipped during processing. The effect of defects on inductance is also large. That is, since the second magnetic layer 12A is more affected by processing than the first magnetic layer 11, the yield can be increased by not forming vertical wiring inside the second magnetic layer 12A.

The first magnetic layer 11 is preferably a composite material of an inorganic filler made of FeSi, FeCo, or FeAl alloy, or an amorphous alloy thereof, and an organic resin such as epoxy, polyimide, or phenol. The content of the inorganic filler is preferably 50 vol % or more based on the organic resin, and the inorganic filler is preferably approximately spherical.

Therefore, the first magnetic layer 11 is a composite material of an inorganic filler and an organic resin, and the content of the inorganic filler is 50 vol% or more. Achieves both properties and workability. Further, since the inorganic filler is approximately spherical, when the vertical wirings 51 and 52 are provided in the first magnetic layer 11, the vertical wirings 51 and 52 tend to slip and be filled into the first magnetic layer 11.

FIG. 6 is an enlarged view of the inductor component 1A. As shown in FIG. 6, in at least a portion between the first magnetic layer 11 and the second magnetic layer 12A, magnetic powder (inorganic filler) 101, There is a region where the amount of 102 is small. This region may be composed of a resin component contained in the first magnetic layer 11 and a resin component contained in the second magnetic layer 12A, or a resin component contained in the first magnetic layer 11 and the second magnetic layer 12A. may be composed of different resins. Hereinafter, this region will be referred to as the resin layer 16.

The resin layer 16 may not contain magnetic powder, but may contain magnetic powder as long as the amount of magnetic powder present is smaller than that of the first magnetic layer 11 and the second magnetic layer 12A. The magnetic powder contained in the resin layer 16 may be the same as the magnetic powder contained in the first and second magnetic layers 11 and 12A.

Therefore, since the resin layer 16 exists between the first magnetic layer 11 and the second magnetic layer 12A, the adhesion between the first magnetic layer 11 and the second magnetic layer 12A is improved, and the inductor component 1A is The strength of the magnetic layer 10 can be improved. Further, by providing the resin layer 16 with less magnetic powder, the magnetic saturation characteristics can be improved.

The thicker the resin layer 16 is, the better the adhesion and magnetic saturation characteristics are. However, if the resin layer 16 is too thick, the inductance acquisition efficiency may be reduced. The thickness of the resin layer 16 is preferably 0.5 μm or more and 30 μm or less. When the thickness of the resin layer 16 is 0.5 μm or more, the adhesion between the first magnetic layer 11 and the second magnetic layer 12A can be further improved, and the magnetic saturation characteristics can be further improved. can be done. When the thickness of the resin layer 16 is 30 μm or less, adhesion and magnetic saturation characteristics are improved, and at the same time, a decrease in inductance acquisition efficiency can be suppressed.

Further, the first magnetic layer 11 includes substantially spherical magnetic powder 101, and the second magnetic layer 12A includes flat magnetic powder 102. In the second magnetic layer 12A, the flat magnetic powders 101 are arranged with their long axes along a direction perpendicular to the normal direction (Z direction). Thereby, in the second magnetic layer 12A, magnetic flux flows along a direction perpendicular to the normal direction (Z direction). Therefore, the second magnetic layer 12A has higher magnetic permeability than the first magnetic layer 11.

Note that different materials or highly filled materials may be used for the first and second magnetic layers 11 and 12A. Alternatively, the effective magnetic permeability of the second magnetic layer 12A may be made higher than that of the first magnetic layer 11 by applying a gradient to the filling amount of magnetic powder in the first and second magnetic layers 11 and 12A.

(Third embodiment)
(composition)
FIG. 7A is a perspective plan view showing a third embodiment of the inductor component. FIG. 7B is a sectional view taken along line XX in FIG. 7A. The third embodiment differs from the first embodiment in the configuration of the spiral wiring. This different configuration will be explained below. Note that in the third embodiment, the same reference numerals as those in the first embodiment have the same configurations as in the first embodiment, so the description thereof will be omitted.

As shown in FIGS. 7A and 7B, like the inductor component 1, the inductor component 1B extends from the spiral wirings 21 and 22 in the Z direction and penetrates the inside of the first magnetic layer 11 or the second magnetic layer 12. Vertical wirings 51 to 53 are provided.

On the other hand, in the inductor component 1B, the spiral wiring includes a plurality of first spiral wirings 21 and second spiral wirings 22, and a second via conductor 27 that connects the first spiral wiring 21 and the second spiral wiring 22 in series. Be prepared for more. Specifically, the first spiral wiring 21 and the second spiral wiring 22 are stacked in the Z direction. The first spiral wiring 21 is spirally wound in a counterclockwise direction from an outer peripheral end 21b toward an inner peripheral end 21a when viewed from above. The second spiral wiring 22 is spirally wound in a counterclockwise direction from an inner peripheral end 22a toward an outer peripheral end 22b when viewed from above.

The outer peripheral end 21b of the first spiral wiring 21 is connected to the first external terminal 41 via the first vertical wiring 51 (the via conductor 25 and the first columnar wiring 31) above the outer peripheral end 21b. The inner peripheral end 21a of the first spiral wiring 21 is connected to the inner peripheral end 22a of the second spiral wiring 22 via the second via conductor 27 below the inner peripheral end 21a.

The outer peripheral end 22b of the second spiral wiring 22 is connected to the second external terminal 42 via the second vertical wiring 52 (the via conductors 25, 26 and the second columnar wiring 32) above the outer peripheral end 22b. The outer peripheral end 22b of the second spiral wiring 22 is connected to the third external terminal 43 via the third vertical wiring 53 (the via conductor 25 and the third columnar wiring 33) below the outer peripheral end 22b. The via conductor 26 extends in the Z direction from the via conductor 25 above the outer peripheral end 22 b of the second spiral wiring 22 and penetrates inside the insulating layer 15 . The via conductor 26 is formed on the same plane as the first spiral wiring 21 .

The same layer as the second via conductor 27 including the second via conductor 27 contains only a conductor, an inorganic filler, and an organic resin. That is, the same layer includes only the second via conductor 27, the insulating layer 15, and the magnetic layer 10. Therefore, since the same layer as the second via conductor 27 does not include a base material such as glass cloth that requires a certain thickness, it is possible to reduce the thickness while relatively reducing the portion that does not contribute to electrical characteristics. Therefore, the electrical characteristics can be improved even if the thickness is the same. Note that "the same layer as the second via conductor 27" refers to a portion (layer) located at the same position as the region from the upper end to the lower end of the second via conductor 27 in the normal direction (Z direction). In other words, it refers to a portion (layer) that is on the same plane as the region from the upper end to the lower end of the second via conductor 27 with respect to a plane parallel to the plane on which the spiral wiring 21 is wound.
On the other hand, conventional inductor components have a non-magnetic printed circuit board, and the thickness of this printed circuit board is as thick as 60 μm, so as the chip thickness becomes thinner, the non-magnetic area of the entire chip occupies more. The percentage will increase. As a result, as the chip thickness becomes thinner, the reduction in inductance acquisition efficiency becomes greater. Also, DC resistance Rdc is an important characteristic index of power inductors, but if you try to reduce the chip thickness while maintaining the DC resistance Rdc, you will need to reduce the chip thickness while maintaining the spiral wiring thickness. Therefore, as a result, the thickness of the magnetic layer becomes thinner, and there is a possibility that the inductance acquisition efficiency decreases and magnetic flux leakage occurs. For example, when magnetic flux leaks to the land pattern side, an eddy current is generated within the conductor of the land pattern, and the generated eddy current generates new magnetic flux in a direction that cancels out the magnetic flux. As a result, the inductance will decrease. Furthermore, there is a concern that the propagation of magnetic noise due to leakage magnetic flux may affect surrounding electronic components.

The thickness of the same layer as the second via conductor 27 is preferably 1 μm or more and 20 μm or less. Therefore, since the thickness of the same layer as the second via conductor 27 is 1 μm or more, short circuits between the spiral wiring can be reliably prevented, and the thickness of the same layer as the second via conductor 27 is 20 μm or less. , it is possible to provide a thin inductor component 1B.

The inorganic filler preferably consists of at least one of a FeSi alloy, a FeCo alloy, a FeAl alloy, an amorphous alloy thereof, and SiO ₂ , and the average particle size of the inorganic filler is preferably 5 μm or less. Therefore, it is possible to reduce loss at high frequencies and ensure insulation.

Furthermore, in the inductor component 1B, since the first spiral wiring 21 and the second spiral wiring 22 are connected in series by the second via conductor 27, the inductance value can be improved by increasing the number of turns. Furthermore, since the first to third vertical wirings 51 to 53 can be brought out from the outer peripheries of the first and second spiral wirings 21 and 22, the inner diameters of the first and second spiral wirings 21 and 22 can be increased. , the inductance value can be improved.

Furthermore, since the first spiral wiring 21 and the second spiral wiring 22 are laminated in the normal direction, the area of the inductor component 1B seen from the Z direction, that is, the mounting area, can be reduced relative to the number of turns, and the inductor component Miniaturization of 1B can be achieved.

Although the inductor component 1B has a configuration including an even number of spiral wirings connected in series, the present invention is not limited to this, and an odd number of spiral wirings may be connected in series. In vertical wiring, the wiring is drawn out from the spiral wiring in the Z direction, so even if an odd number of spiral wirings are connected in series and one end of the inductor is placed on the inner periphery, the end is connected to the outer periphery. There is no need to pull it out to the side. Therefore, in this case, a reduction in thickness can be achieved. Further, since the degree of freedom in the number of spiral wirings connected in series is improved in this way, the degree of freedom in the setting range of the inductance value is also improved.

Further, in the inductor component 1B, one inductor made of two layers of spiral wiring is arranged on the same plane, but two or more inductors may be arranged on the same plane.

(Production method)
Next, a method for manufacturing the inductor component 1B will be described.

First, the steps shown in FIGS. 4A to 4C of the method for manufacturing the inductor component 1 are performed. Subsequently, as shown in FIG. 8A, the first dummy copper 64a and the first spiral wiring 64b are covered with a first insulating layer 65. The insulating layer 65 is thermocompressed and thermally cured using a vacuum laminator, a press machine, or the like.

Then, as shown in FIG. 8B, by laser processing or the like, the insulating layer 65 on the dummy copper 64a is opened to form an opening 65a, and the insulating layer 65 on the end of the spiral wiring 64b is opened to form the opening. 65b.

Next, as shown in FIG. 8C, SAP and subsequent additional copper electrode plating are performed in the same manner as in FIG. 8C to form second dummy copper 81a and second spiral wiring 81b. Note that when increasing the number of layers of spiral wiring, the steps from FIG. 8A to FIG. 8C may be repeated.

Then, as shown in FIG. 8D, the second dummy copper 81a and the second spiral wiring 81b are covered with a second insulating layer 82. The insulating layer 82 is thermocompression bonded and thermosetted using a vacuum laminator, a press machine, or the like. Then, an opening 82a in the insulating layer 82 on the second dummy copper 81a is formed by laser processing or the like.

Thereafter, the dummy core substrate 61 is peeled off from the copper foil 62. Then, the copper foil 62 is removed by etching or the like, and the dummy copper 64a is removed by etching or the like to form a hole 66a corresponding to the inner magnetic path and a hole 66b corresponding to the outer magnetic path, as shown in FIG. 8E. .

Thereafter, as shown in FIG. 8F, an opening 87a is formed in the insulating layer 82 by laser processing or the like. Then, as shown in FIG. 8G, the opening 87a of the insulating layer 82 is filled with copper using SAP, and the columnar wiring 68 is formed on the insulating layer 82.

Next, as shown in FIG. 8H, the spiral wiring, the insulating layer, and the columnar wiring are covered with a magnetic material (magnetic layer) 69 to form an inductor substrate. The magnetic material 69 is thermally pressed and hardened using a vacuum laminator, press machine, or the like. At this time, the magnetic material 69 is also filled in the holes 66a and 66b.

Then, as shown in FIG. 8I, the magnetic material 69 on the top and bottom of the inductor substrate is thinned by a grinding method. At this time, by exposing a portion of the columnar wiring 68, an exposed portion of the columnar wiring 68 is formed on the same plane of the magnetic material 69.

Thereafter, as shown in FIG. 8J, an insulating resin (insulating layer) 70 is formed on the surface of the magnetic material by a printing method. Here, the opening 70a of the insulating resin 70 is used as a portion where an external terminal is formed. Although the printing method is used in the above example, the opening 70a may be formed using a photolithography method.

Next, as shown in FIG. 8K, electroless copper plating or plating film such as Ni and Au is applied to form external terminals 71a, and as shown in FIG. The inductor component 1B shown in FIG. 7 is obtained. Note that inductor substrates may be formed on both sides of the dummy core substrate 61. Thereby, high productivity can be obtained.

Note that the present disclosure is not limited to the above-described embodiments, and design changes can be made without departing from the gist of the present disclosure. For example, the features of the first to third embodiments may be combined in various ways.

In addition, in the first to third embodiments, even if the effects described in other embodiments are not specifically mentioned or the explanation is omitted in the embodiments, the same effects may be used in the first to third embodiments. In this case, basically the same effects can be achieved in this embodiment as well.

1, 1A, 1B Inductor parts 10 Magnetic layer 11 First magnetic layer 12, 12A Second magnetic layer 13 Inner magnetic path section 14 Outer magnetic path section 15 Insulating layer 16 Resin layer (area with a small amount of magnetic powder)
21 First spiral wiring 22 Second spiral wiring 25 Via conductor 31 First pillar wiring 32 Second pillar wiring 33 Third pillar wiring 41 First external terminal 42 Second external terminal 43 Third external terminal 50 Covering film 51 First Vertical wiring 52 Second vertical wiring 53 Third vertical wiring

Claims (15)

Spiral wiring wound on a flat surface,
a first magnetic layer and a second magnetic layer sandwiching the spiral wiring from both sides in the normal direction to the plane around which the spiral wiring is wound;
a first vertical wiring extending from the spiral wiring in the normal direction and penetrating inside the first magnetic layer ;
a second vertical wiring extending from the spiral wiring in the normal direction and penetrating inside the second magnetic layer;
an external terminal provided on the surface of the first magnetic layer and the surface of the second magnetic layer,
The external terminal is in direct contact with a part of the surface of the first magnetic layer, and a first external terminal that covers an end face of the first vertical wiring, and a part of the surface of the second magnetic layer, and a second external terminal that covers an end surface of the second vertical wiring,
In plan view from the normal direction, the area of the first external terminal is larger than the area of the second external terminal ,
The thickness of the first magnetic layer is thicker than the thickness of the second magnetic layer,
An inductor component, wherein A/((A+B)/2) is greater than 1.0 and less than or equal to 1.15, where A is the thickness of the first magnetic layer and B is the thickness of the second magnetic layer. Spiral wiring wound on a flat surface,
a first magnetic layer and a second magnetic layer sandwiching the spiral wiring from both sides in the normal direction to the plane around which the spiral wiring is wound;
a first vertical wiring extending from the spiral wiring in the normal direction and penetrating inside the first magnetic layer ;
a second vertical wiring extending from the spiral wiring in the normal direction and penetrating inside the second magnetic layer;
an external terminal provided on the surface of the first magnetic layer and the surface of the second magnetic layer,
The external terminal is in direct contact with a part of the surface of the first magnetic layer and covers an end surface of the first vertical wiring, and the external terminal is in direct contact with a part of the surface of the second magnetic layer, and a second external terminal that covers an end surface of the second vertical wiring,
In plan view from the normal direction, the area of the first external terminal is larger than the area of the second external terminal ,
The thickness of the first magnetic layer is thicker than the thickness of the second magnetic layer,
An inductor component, wherein A/((A+B)/2) is greater than 1.0 and less than or equal to 1.3, where A is the thickness of the first magnetic layer and B is the thickness of the second magnetic layer. The inductor component according to claim 1 or 2 , wherein the thickness of the first magnetic layer and the thickness of the second magnetic layer are each 10 μm or more. The inductor component according to any one of claims 1 to 3 , wherein the spiral wiring is a conductor made of copper or a copper compound. The inductor component according to any one of claims 1 to 4 , wherein the spiral wiring is covered with an insulating resin made of an inorganic filler and an organic resin. The inductor component according to any one of claims 1 to 5 , wherein the inductor component has a thickness of 0.35 mm or less. The inductor component according to any one of claims 1 to 6 , wherein the thickness of the spiral wiring is thicker than (A+B)/2 and thinner than 2(A+B). The inductor component according to claim 7 , wherein the inductor component has a thickness of 0.2 mm or less. The inductor component according to any one of claims 1 to 8 , wherein the second magnetic layer has a higher magnetic permeability than the first magnetic layer. The first magnetic layer is a composite material of an inorganic filler made of FeSi-based, FeCo-based, FeAl-based alloy, or an amorphous alloy thereof, and an epoxy, polyimide, or phenol-based organic resin,
The inductor component according to claim 9 , wherein the content of the inorganic filler is 50 vol% or more with respect to the organic resin, and the inorganic filler has a substantially spherical shape. From claim 8 , there is a region in which the amount of magnetic powder is smaller than in the first magnetic layer and the second magnetic layer, at least in a part between the first magnetic layer and the second magnetic layer. 10. The inductor component according to any one of 10 . The inductor component according to claim 11 , wherein the thickness of the region is 0.5 μm or more and 30 μm or less. There are multiple spiral wirings,
Further comprising a via conductor connecting the spiral wirings in series between the plurality of spiral wirings,
The inductor component according to claim 1 or 2 , wherein the same layer as the via conductor that includes the via conductor contains only a conductor, an inorganic filler, and an organic resin. The inductor component according to claim 13 , wherein the thickness of the same layer as the via conductor is 1 μm or more and 20 μm or less. 14. The inorganic filler is made of at least one of a FeSi alloy, a FeCo alloy, a FeAl alloy, an amorphous alloy thereof, and _SiO2 , and the inorganic filler has an average particle size of 5 μm or less. Inductor parts listed in.

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