JP6874601B2 - Coil parts and their manufacturing methods - Google Patents

Description

The present invention relates to a coil component and a method for manufacturing the same, and more particularly to a coil component provided with a magnetic resin layer in which a coil pattern is embedded and a method for manufacturing the coil component.

As a coil component in which a coil pattern is embedded in a magnetic resin layer, the coil component described in Patent Document 1 is known. The coil component described in Patent Document 1 includes a magnetic resin layer provided in the lower region of the coil pattern, and a magnetic resin layer provided in the inner diameter region, the outer peripheral region, and the upper region of the coil pattern. It has a structure in which a coil pattern is embedded by two magnetic resin layers.

Japanese Unexamined Patent Publication No. 2012-114444

Since the magnetic resin layer is a composite member made of a resin containing magnetic powder such as ferrite powder or metal magnetic particles, the interfaces of the two magnetic resin layers are in direct contact with each other, or face each other via an insulating gap layer or the like. This causes a problem that the density of the magnetic powder decreases at the interface portion and the magnetic permeability of the magnetic resin layer locally decreases.

Therefore, an object of the present invention is to provide a coil component in which a local decrease in the magnetic permeability of the magnetic resin layer is prevented, and a method for manufacturing the coil component.

The coil component according to the present invention includes a coil pattern, a first magnetic resin layer provided in a lower region covering the coil pattern from one side in the axial direction, an inner diameter region surrounded by the coil pattern, and an outer peripheral region surrounding the coil pattern. , And a second magnetic resin layer provided in the upper region covering the coil pattern from the other side in the axial direction, the first and second magnetic resin layers contain metal magnetic particles, and the second magnetic resin. A plurality of cut surfaces of the metal magnetic particles are exposed from the inner surface of the first magnetic resin layer facing the layer.

According to the present invention, since a plurality of cut surfaces of the metal magnetic particles are exposed from the inner surface of the first magnetic resin layer, the magnetic permeability in the vicinity of the inner surface of the first magnetic resin layer is locally reduced. Can be prevented. The ratio of the cut surface of the metal magnetic particles exposed from the inner surface of the first magnetic resin layer may be 20% or more and 80% or less in cross-sectional view.

In the present invention, an insulating coat layer may be formed on the surface of the metal magnetic particles. According to this, it is possible to sufficiently increase the volume resistance of the first magnetic resin layer.

In the present invention, a plurality of cut surfaces of the metal magnetic particles may be exposed from the inner surface of the second magnetic resin layer facing the first magnetic resin layer. According to this, it is possible to prevent a local decrease in the magnetic permeability in the vicinity of the inner surface of the second magnetic resin layer.

In the present invention, the first magnetic resin layer and the second magnetic resin layer may be made of the same material. According to this, it is possible to reduce the material cost.

In the present invention, the metal magnetic particles contained in the first and second magnetic resin layers may have a plurality of particle sizes having different particle size distributions from each other. According to this, it becomes possible to fill the first and second magnetic resin layers with higher metal magnetic particles.

In the present invention, the outer surface located on the side opposite to the inner surface of the first magnetic resin layer may have a larger surface roughness than the inner surface. According to this, it is possible to improve the heat dissipation from the outer surface.

The coil component according to the present invention may further include an insulating gap layer provided between the inner surface of the first magnetic resin layer and the inner surface of the second magnetic resin layer. According to this, since the insulating gap layer functions as a magnetic gap, it is possible to suppress magnetic saturation.

The method for manufacturing a coil component according to the present invention includes a step of forming a coil pattern on a carrier plate, an inner diameter region surrounded by the coil pattern, an outer peripheral region surrounding the coil pattern, and covering the coil pattern from one side in the axial direction. A step of forming a second magnetic resin layer containing the metal magnetic particles and a first magnetic resin layer containing the metal magnetic particles are prepared in the upper region, and the metal magnetic particles are formed from the inner surface of the first magnetic resin layer. After the step of polishing the inner surface so that the cut surface is exposed and the carrier plate being peeled off, the first magnetic resin layer is formed so that the inner surface of the first magnetic resin layer faces the second magnetic resin layer. It is characterized by comprising a step of forming.

According to the present invention, since the density of the metal magnetic particles in the vicinity of the inner surface of the first magnetic resin layer is maintained at the same level as the density in the other regions, the transparency in the vicinity of the inner surface of the first magnetic resin layer is maintained. It is possible to prevent a local decrease in magnetic coefficient.

In the present invention, the steps of forming the second magnetic resin layer include a step of polishing the inner surface so that the cut surface of the metal magnetic particles is exposed from the inner surface of the second magnetic resin layer, and a second magnetic resin layer. It may include a step of forming a second magnetic resin layer so that the inner surface of the surface faces the carrier plate. According to this, since the density of the metal magnetic particles in the vicinity of the inner surface of the second magnetic resin layer is maintained at the same level as the density in the other regions, the magnetic permeability in the vicinity of the inner surface of the second magnetic resin layer Can be prevented from locally decreasing.

In the present invention, the carrier plate supports an insulating gap layer, and the step of forming the coil pattern may be performed by forming the coil pattern on the surface of the insulating gap layer. According to this, it is possible to form an insulating gap layer which is a magnetic gap between the first magnetic resin layer and the second magnetic resin layer.

As described above, according to the present invention, it is possible to provide a coil component in which a local decrease in the magnetic permeability of the magnetic resin layer is prevented, and a method for manufacturing the coil component.

FIG. 1 is a perspective view showing the appearance of the coil component 10 according to a preferred embodiment of the present invention. FIG. 2 is a cross-sectional view of the coil component 10. FIG. 3 is an enlarged view of the region A shown in FIG. FIG. 4 is a process diagram for explaining the manufacturing process of the coil component 10. FIG. 5 is a process diagram for explaining the manufacturing process of the coil component 10. FIG. 6 is a process diagram for explaining the manufacturing process of the coil component 10. FIG. 7 is a process diagram for explaining the manufacturing process of the coil component 10. FIG. 8 is a process diagram for explaining the manufacturing process of the coil component 10. FIG. 9 is a process diagram for explaining the manufacturing process of the coil component 10.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the appearance of the coil component 10 according to a preferred embodiment of the present invention.

The coil component 10 according to the present embodiment is a surface mount type chip component suitable to be used as an inductor for a power supply circuit, and has first and second magnetic resin layers 11 and 12 as shown in FIG. A coil pattern described later is embedded in the first and second magnetic resin layers 11 and 12, one end of the coil pattern is connected to the first external terminal E1, and the other end of the coil pattern is the second outer. It is connected to terminal E2. However, it is not essential that the coil component according to the present invention is a surface mount type chip component, and a chip component of a type embedded in a circuit board may be used.

The first and second magnetic resin layers 11 and 12 are composite members made of a resin containing metal magnetic particles, and form a magnetic path of magnetic flux generated by passing an electric current through the coil pattern. As the metal magnetic particles, it is preferable to use a permalloy-based material. Further, as the resin, it is preferable to use a semi-cured epoxy resin which is a liquid or powder. The first and second magnetic resin layers 11 and 12 may be made of the same material or may be made of different materials. If the same materials are used as the materials for the first and second magnetic resin layers 11 and 12, the material cost can be reduced.

The coil component 10 according to the present embodiment is mounted upright so that the z direction, which is the stacking direction, is parallel to the circuit board, unlike a general laminated coil component. Specifically, the surface forming the xz surface is used as the mounting surface S1. The mounting surface S1 is provided with a first external terminal E1 and a second external terminal E2. The first external terminal E1 is continuously formed from the mounting surface S1 to the side surface S2 forming the yz surface, and the second external terminal E2 extends from the mounting surface S1 to the side surface S3 forming the yz surface. It is formed continuously.

FIG. 2 is a cross-sectional view of the coil component 10 according to the present embodiment.

As shown in FIG. 2, coil patterns C made of good conductors such as copper (Cu) are embedded in the first and second magnetic resin layers 11 and 12. In the present embodiment, the coil pattern C has a four-layer structure, and each layer has a two-turn spiral shape. As a result, the coil pattern C has a total of eight turns. Further, the surface of the coil pattern C is covered with the insulating gap layer 30 and the interlayer insulating layers 41 to 44, whereby contact with the first and second magnetic resin layers 11 and 12 is prevented.

The first magnetic resin layer 11 is provided in the lower region 21 that covers the coil pattern C from one side in the axial direction (z direction). On the other hand, the second magnetic resin layer 12 is provided in the inner diameter region 22 surrounded by the coil pattern C, the outer peripheral region 23 surrounding the coil pattern C, and the upper region 24 covering the coil pattern C from the other side in the axial direction. ing. An insulating gap layer 30 is provided between the first magnetic resin layer 11 and the second magnetic resin layer 12.

The insulating gap layer 30 is made of a non-magnetic material such as a resin, and plays a role of preventing magnetic saturation by forming a magnetic gap between the first magnetic resin layer 11 and the second magnetic resin layer 12. However, in the present invention, it is not essential to provide the insulating gap layer 30, and the first magnetic resin layer 11 and the second magnetic resin layer 12 may be in direct contact with each other.

FIG. 3 is an enlarged view of the region A shown in FIG.

As shown in FIG. 3, the first and second magnetic resin layers 11 and 12 have a structure in which a large number of metal magnetic particles M are dispersed in the resin material R. The size of the metal magnetic particles M is not particularly limited, but it is preferable that the metal magnetic particles M have a plurality of particle sizes having different particle size distributions. According to this, the resin material R can be filled with the metal magnetic particles M at a higher level. The shape of the metal magnetic particles M is also not particularly limited, but is preferably spherical in order to fill the metal magnetic particles M more highly. It is preferable that an insulating coat layer I is formed on the surface of the metal magnetic particles M. According to this, it is possible to sufficiently secure the volume resistance of the first and second magnetic resin layers 11 and 12.

On the inner surface 11a of the first magnetic resin layer 11 and the inner surface 12a of the second magnetic resin layer 12, not the surface of the insulating coat layer I but the cut surface of the spherical metal magnetic particles M is exposed. .. That is, the metal magnetic particles M are cut in the vicinity of the inner surfaces 11a and 12a, and the cut surface is exposed on the inner surfaces 11a and 12a. Here, the inner surface 11a is a surface in contact with the back surface 32 of the insulating gap layer 30, and refers to a surface facing the second magnetic resin layer 12. Similarly, the inner surface 12a is a surface in contact with the surface 31 of the insulating gap layer 30, and refers to a surface facing the first magnetic resin layer 11.

As described above, the metal magnetic particles M are cut in the vicinity of the inner surfaces 11a and 12a of the first and second magnetic resin layers 11 and 12, and the cut surface is exposed. Therefore, the metal magnetic particles Compared with the case where M is not cut, the density of the metal magnetic particles M in the vicinity of the inner surfaces 11a and 12a is increased. That is, since the same metal magnetic particles M cannot exist in both the first magnetic resin layer 11 and the second magnetic resin layer 12, the metal magnetic particles M are cut in the vicinity of the inner surfaces 11a and 12a. If not, the density of the metal magnetic particles M decreases in the vicinity of the inner surfaces 11a and 12a, and the magnetic permeability decreases locally. However, in the present embodiment, the metal magnetic particles M are cut in the vicinity of the inner surfaces 11a and 12a, and the cut surface is exposed from the inner surfaces 11a and 12a. The density is ensured, and it is possible to prevent the local magnetic permeability from decreasing.

Specifically, on the inner surfaces 11a and 12a of the first and second magnetic resin layers 11 and 12, the ratio of the metal magnetic particles M exposed is preferably 20% or more and 80% or less in a cross-sectional view. .. For example, in the cross section shown in FIG. 3, the total value of the length Lm of the metal magnetic particles M exposed on the inner surface 11a of the first magnetic resin layer 11 is 20% or more and 80% or less of the length L of the cross section. Is. On the other hand, when the metal magnetic particles M are not cut in the vicinity of the inner surfaces 11a and 12a, the exposure ratio of the metal magnetic particles M is less than 20% even when the metal magnetic particles M are highly filled. The magnetic permeability decreases in the vicinity of the inner surfaces 11a and 12a. On the other hand, since the filling rate of the metal magnetic particles M is limited, the exposure ratio of the metal magnetic particles M exceeds 80% even when the metal magnetic particles M are cut in the vicinity of the inner surfaces 11a and 12a. Is difficult to do.

The structure shown in FIG. 3 is obtained by polishing the inner surfaces 11a and 12a of the first and second magnetic resin layers 11 and 12 in the manufacturing process described later. Therefore, the inner surfaces 11a and 12a of the first and second magnetic resin layers 11 and 12 have a small surface roughness. On the other hand, the other surfaces of the first and second magnetic resin layers 11 and 12, for example, the outer surface located on the side opposite to the inner surfaces 11a and 12a, are not polished, and therefore the inner surfaces 11a and 12a. The surface roughness is larger than that. According to this, since the surface areas of the first and second magnetic resin layers 11 and 12 are increased, it is possible to secure high heat dissipation.

As described above, in the coil component 10 according to the present embodiment, since the cut surface of the metal magnetic particles M is exposed on the inner surfaces 11a and 12a of the first and second magnetic resin layers 11 and 12, it is local. It is possible to prevent a decrease in magnetic permeability. However, in the present invention, it is not essential to expose the cut surface of the metal magnetic particles M on both the inner surfaces 11a and 12a of the first and second magnetic resin layers 11 and 12, and at least the first magnetic resin. It suffices if the cut surface of the metal magnetic particles M is exposed on the inner surface 11a of the layer 11.

Next, a method of manufacturing the coil component 10 according to the present embodiment will be described.

4 to 9 are process diagrams for explaining the manufacturing process of the coil component 10 according to the present embodiment.

First, as shown in FIG. 4A, a carrier plate 50 having a predetermined strength is prepared, and an insulating gap layer 30 is formed on the upper surface thereof. The material of the carrier plate 50 is not particularly limited as long as a predetermined mechanical strength can be secured, and glass, ferrite, or the like can be used. Further, the method of forming the insulating gap layer 30 is not particularly limited, and the insulating gap layer 30 may be formed by applying a resin material to the surface of the carrier plate 50 by a spin coating method or a printing method, or may be formed in advance in a film shape. The gap layer 30 may be attached to the carrier plate 50.

Next, as shown in FIG. 4B, the first conductor layer C1 forming the coil pattern C is formed on the surface 31 of the insulating gap layer 30. As a method for forming the conductor layer C1, it is preferable that a base metal film is formed by using a thin film process such as a sputtering method, and then plating is grown to a desired film thickness by using an electrolytic plating method. The same applies to the method of forming the conductor layers C2 to C4 of the second to fourth layers of the coil pattern C to be formed thereafter.

Next, as shown in FIG. 4C, after forming the interlayer insulating layer 41 covering the first conductor layer C1, the second conductor layer C2 is formed on the upper surface of the interlayer insulating layer 41. After that, as shown in FIGS. 5A to 5C, by repeating this step, the interlayer insulating layers 41 to 44 and the conductor layers C1 to C4 of the coil pattern C are alternately formed.

Next, as shown in FIG. 6A, by performing milling or dry etching, the interlayer insulating films 41 to 44 of the portions corresponding to the inner diameter region 22 and the outer peripheral region 23 of the coil pattern C are removed in a plan view. .. At this time, when the insulating gap layer 30 remains between the first magnetic resin layer 11 and the second magnetic resin layer 12, the insulating gap layer 30 must not be removed. As a result, a space is formed in the inner diameter region 22 surrounded by the coil pattern C and the outer peripheral region 23 located outside the coil pattern C.

Next, as shown in FIG. 6B, a second magnetic resin layer 12 in a semi-cured state held on a film 51 made of PET resin or the like is prepared, and the inner surface of the second magnetic resin layer 12 is prepared. The inner surface 12a is polished so that the cut surface of the metal magnetic particles M is exposed from 12a.

Then, as shown in FIG. 6C, the inner surface 12a of the second magnetic resin layer 12 is pressed so as to face the carrier plate 50. As a result, the second magnetic resin layer 12 is formed in the inner diameter region 22, the outer peripheral region 23, and the upper region 24 of the coil pattern C, and the cut surface of the metal magnetic particles M contained in the second magnetic resin layer 12 is formed. A structure in contact with the surface 31 of the insulating gap layer 30 can be obtained. Alternatively, a semi-cured composite member made of a resin containing metal magnetic particles may be embedded in the space formed by removing the interlayer insulating films 41 to 44 by a printing method. However, in this case, the metal magnetic particles M contained in the second magnetic resin layer 12 are not cut, and the density of the metal magnetic particles M on the inner surface 12a decreases.

Next, as shown in FIG. 7A, after the film 51 is peeled off, the second magnetic resin layer 12 is pressed to open the gaps formed in the inner diameter region 22 and the outer circumference region 23 of the coil pattern C. It is completely filled with the second magnetic resin layer 12.

Next, as shown in FIG. 7 (b), the support plate 60 is attached to the second magnetic resin layer 12 via the adhesive 61, and then the carrier plate 50 is peeled off as shown in FIG. 7 (c). To do. Examples of the method for peeling the carrier plate 50 include mechanical peeling and thermal peeling by laser irradiation. As a result, the back surface 32 of the insulating gap layer 30 is exposed. The support plate 60 is a support member in the step of peeling the carrier plate 50, and when it is not necessary to support the entire support plate 60 in the step of peeling the carrier plate 50, it is not necessary to attach the support plate 60.

Next, as shown in FIG. 8 (a), the support plate 60 is peeled off and then turned upside down as shown in FIG. 8 (b). Then, a semi-cured first magnetic resin layer 11 held on the film 52 made of PET resin or the like is prepared, and the cut surface of the metal magnetic particles M is exposed from the inner surface 11a of the first magnetic resin layer 11. The inner surface 11a is polished so as to do so.

Then, as shown in FIG. 8C, the inner surface 11a of the first magnetic resin layer 11 is pressed so as to face the carrier plate 50. As a result, the first magnetic resin layer 11 is formed on the back surface 32 of the insulating gap layer 30, and the cut surface of the metal magnetic particles M contained in the first magnetic resin layer 11 is in contact with the back surface 32 of the insulating gap layer 30. Is obtained.

Next, as shown in FIG. 9A, pressure is applied to the first and second magnetic resin layers 11 and 12 by pressing the first and second magnetic resin layers 11 and 12. After that, the first and second magnetic resin layers 11 and 12 are completely cured by applying heat or ultraviolet rays to the semi-cured first and second magnetic resin layers 11 and 12. Then, the film 52 is peeled off.

Then, as shown in FIG. 9B, if the terminal electrodes E1 and E2 shown in FIG. 1 are formed after the individual pieces are separated by dicing, the coil component 10 according to the present embodiment is completed.

As described above, according to the present embodiment, since the inner surfaces 11a and 12a of the first and second magnetic resin layers 11 and 12 are polished and then pressed, the metal magnetic particles are formed from the inner surfaces 11a and 12a. It is possible to obtain a state in which the cross section of M is exposed. This makes it possible to prevent a local decrease in the magnetic permeability in the vicinity of the inner surfaces of the inner surfaces 11a and 12a of the first and second magnetic resin layers 11 and 12.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention, and these are also the present invention. Needless to say, it is included in the range.

For example, the coil component in the above embodiment includes a coil pattern C having a spiral pattern of 8 turns, but the specific pattern shape of the coil pattern is not limited to this in the present invention.

10 Coil component 11 First magnetic resin layer 11a Inner surface of first magnetic resin layer 12 Second magnetic resin layer 12a Inner surface of second magnetic resin layer 21 Lower region 22 Inner diameter region 23 Outer region 24 Upper region 30 Insulation gap layer 31 Front surface of insulation gap layer 32 Back surface of insulation gap layer 41-44 Interlayer insulation layer 50 Carrier plate 51, 52 Film 60 Support plate 61 Adhesive C Coil pattern C1 to C4 Conductor layer E1, E2 Terminal electrode I Insulation coat Layer M Metal magnetic particles R Resin material S1 Mounting surface S2, S3 Side surface

Claims (11)

With the coil pattern
A first magnetic resin layer provided in the lower region covering the coil pattern from one side in the axial direction, and
An inner diameter region surrounded by the coil pattern, an outer peripheral region surrounding the coil pattern, and a second magnetic resin layer provided in an upper region covering the coil pattern from the other side in the axial direction are provided.
The first and second magnetic resin layers contain metal magnetic particles and contain metal magnetic particles.
A coil component characterized in that a plurality of cut surfaces of the metal magnetic particles are exposed from the inner surface of the first magnetic resin layer facing the second magnetic resin layer. The coil according to claim 1, wherein the ratio of the cut surface of the metal magnetic particles exposed from the inner surface of the first magnetic resin layer is 20% or more and 80% or less in a cross-sectional view. parts. The coil component according to claim 1 or 2, wherein an insulating coat layer is formed on the surface of the metal magnetic particles. Any of claims 1 to 3, wherein a plurality of cut surfaces of the metal magnetic particles are exposed from the inner surface of the second magnetic resin layer facing the first magnetic resin layer. The coil component described in item 1. The coil component according to any one of claims 1 to 4, wherein the first magnetic resin layer and the second magnetic resin layer are made of the same material. The invention according to any one of claims 1 to 5, wherein the metal magnetic particles contained in the first and second magnetic resin layers have a plurality of particle sizes having different particle size distributions from each other. Coil parts. The coil according to any one of claims 1 to 6, wherein the outer surface located on the side opposite to the inner surface of the first magnetic resin layer has a surface roughness larger than that of the inner surface. parts. Any one of claims 1 to 7, further comprising an insulating gap layer provided between the inner surface of the first magnetic resin layer and the inner surface of the second magnetic resin layer. The coil parts described in the section. The process of forming a coil pattern on the carrier plate and
A step of forming a second magnetic resin layer containing metal magnetic particles in an inner diameter region surrounded by the coil pattern, an outer peripheral region surrounding the coil pattern, and an upper region covering the coil pattern from one side in the axial direction. When,
A step of preparing a first magnetic resin layer containing metal magnetic particles and polishing the inner surface so that the cut surface of the metal magnetic particles is exposed from the inner surface of the first magnetic resin layer.
It is characterized by comprising a step of forming the first magnetic resin layer so that the inner surface of the first magnetic resin layer faces the second magnetic resin layer after the carrier plate is peeled off. How to manufacture coil parts. The steps of forming the second magnetic resin layer include a step of polishing the inner surface so that the cut surface of the metal magnetic particles is exposed from the inner surface of the second magnetic resin layer, and a step of polishing the inner surface of the second magnetic resin layer. The method for manufacturing a coil component according to claim 9, further comprising a step of forming the second magnetic resin layer so that the inner surface of the layer faces the carrier plate. The ninth or tenth aspect of the present invention, wherein an insulating gap layer is supported on the carrier plate, and the step of forming the coil pattern is performed by forming a coil pattern on the surface of the insulating gap layer. How to manufacture coil parts.

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