JP7618476B2 - Coil component and manufacturing method thereof - Google Patents

Description

The present invention relates to coil components and manufacturing methods thereof, and in particular to coil components having a structure in which a magnetic material is embedded in the inner diameter region of a spirally wound spiral pattern, and to a manufacturing method thereof.

The coil component described in Patent Document 1 is known as a coil component having a structure in which spiral patterns wound in a spiral shape are stacked. The coil component described in Patent Document 1 has a structure in which a magnetic member is embedded in the inner diameter region of the spiral pattern, which increases the inductance.

JP 2019-140202 A

However, in the coil component described in Patent Document 1, a portion of the insulating resin layer protrudes into the inner diameter region of the spiral pattern, and there is a risk that such a protrusion may prevent the embedding of the magnetic material.

Therefore, the present invention aims to provide a coil component having a structure that makes it easy to embed a magnetic material in the inner diameter region of the spiral pattern, and a manufacturing method thereof.

The coil component according to the present invention comprises first and second magnetic members, a plurality of conductor layers each including a spiral pattern wound in a spiral shape, disposed between the first and second magnetic members, a plurality of insulating resin layers each provided between the plurality of conductor layers, and a third magnetic member embedded in the inner diameter region of the spiral pattern, the plurality of insulating resin layers having a first protrusion protruding into the inner diameter region, and the first protrusion of the insulating resin layer located at one end side of the coil axis direction among the plurality of insulating resin layers protruding by a shorter amount than the first protrusion of at least one other insulating resin layer.

According to the present invention, the first protruding portion of the insulating resin layer located at one end side of the coil axis direction is short, so it is easy to embed the third magnetic member in the inner diameter region from one end side of the coil axis direction. Moreover, since a larger amount of magnetic member can be embedded in the inner diameter region, it is also possible to increase the inductance.

In the present invention, some of the first protrusions may protrude longer from one end of the coil axial direction to the other end. In this case, it is also easier to embed the third magnetic member in the inner diameter region from one end of the coil axial direction. Moreover, since the protrusions near the other end of the coil axial direction are relatively long, damage caused by removing the protrusions is minimized.

In the present invention, the first protrusion of the insulating resin layer located at the other end side in the coil axis direction among the multiple insulating resin layers may protrude less than the first protrusion of at least one other insulating resin layer. This allows more magnetic material to be embedded in the inner diameter region, thereby further increasing the inductance.

The coil component according to the present invention further comprises a fourth magnetic member located in the outer region of the spiral pattern, and the multiple insulating resin layers further have second protrusions protruding into the outer region, and the second protrusion of the insulating resin layer located at one end side of the coil axis direction among the multiple insulating resin layers may protrude less than the second protrusion of at least one other insulating resin layer. This makes it easier to embed the fourth magnetic member in the outer region from one end side of the coil axis direction when manufacturing multiple coil components by multiple piece production. Moreover, since more magnetic members can be embedded in the outer region, it is also possible to increase the inductance.

The manufacturing method of the coil component according to the present invention is characterized by comprising the steps of alternately laminating a plurality of conductor layers and a plurality of insulating resin layers, including a spiral pattern wound in a spiral shape and a sacrificial pattern located in the inner diameter region of the spiral pattern, forming a space in the inner diameter region of the spiral pattern by removing the sacrificial pattern, removing a part of the protruding portion made of the plurality of insulating resin layers protruding into the space, and embedding a magnetic member in the space.

According to the present invention, a portion of the protruding portion made of the insulating resin layer is removed, making it easier to fill the space with a magnetic member.

In this way, the present invention makes it possible to provide a coil component and a manufacturing method thereof that has a structure that makes it easy to embed a magnetic material in the inner diameter region of the spiral pattern.

FIG. 1 is a schematic cross-sectional view for explaining the structure of a coil component 1 according to an embodiment of the present invention. FIG. 2 is a schematic plan view of the conductor layer 10. As shown in FIG. FIG. 3 is a schematic plan view of the conductor layers 20 and 40. As shown in FIG. FIG. 4 is a schematic plan view of the conductor layers 30 and 50. As shown in FIG. FIG. 5 is a schematic plan view of the conductor layer 60. As shown in FIG. FIG. 6 is a schematic cross-sectional view for explaining the shape of the protrusions provided on the insulating resin layers 70 to 76. As shown in FIG. FIG. 7 is a schematic cross-sectional view for explaining the shape of the protrusion according to the first modified example. FIG. 8 is a schematic cross-sectional view for explaining the shape of the protrusion according to the second modified example. FIG. 9 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 10 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 11 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 12 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 13 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 14 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 15 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 16 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 17 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 18 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 19 is a process diagram for explaining a manufacturing method of the coil component 1. FIG. 20 is a process diagram for explaining a manufacturing method of the coil component 1.

A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

Figure 1 is a schematic cross-sectional view illustrating the structure of a coil component 1 according to one embodiment of the present invention.

The coil component 1 according to the first embodiment is a surface-mount type chip component, and as shown in FIG. 1, includes magnetic members M1 to M4 and a coil pattern C embedded in the magnetic members M1 to M4. The configuration of the coil pattern C will be described later, but in this embodiment, it is made up of spiral patterns SP1 to SP6 wound in a spiral shape with multiple turns.

The magnetic members M1 to M4 are composite members containing a metal magnetic filler made of iron (Fe) or a permalloy-based material and a resin binder, and constitute a magnetic path for the magnetic flux generated by passing a current through the coil pattern C. As the resin binder, it is preferable to use a liquid or powdered epoxy resin. The materials constituting the magnetic members M1 to M4 may be the same as each other or may be different from each other. Here, the magnetic member M1 is a part that covers the coil pattern C from one side in the axial direction (the upper side shown in FIG. 1), the magnetic member M2 is a part that covers the coil pattern C from the other side in the axial direction (the lower side shown in FIG. 1), the magnetic member M3 is a part that is embedded in the inner diameter region of the coil pattern C, and the magnetic member M4 is a part that is located in the outer region in the radial direction of the coil pattern C. The magnetic member M2 may be a magnetic substrate made of ferrite or the like.

As shown in Figure 1, insulating resin layers 70-76 and conductor layers 10, 20, 30, 40, 50, 60 are alternately stacked in the axial direction. The planar shape of conductor layer 10 is shown in Figure 2, the planar shapes of conductor layers 20 and 40 are shown in Figure 3, the planar shapes of conductor layers 30 and 50 are shown in Figure 4, and the planar shape of conductor layer 60 is shown in Figure 5. Conductor layers 10, 20, 30, 40, 50, 60 each have spiral patterns SP1-SP6, and the upper or lower surfaces of spiral patterns SP1-SP6 are covered with insulating resin layers 70-76. The side surfaces of spiral patterns SP1-SP6 are each covered with a portion of insulating resin layers 71-76. Here, the upper and lower surfaces of the spiral patterns SP1 to SP6 refer to surfaces that are approximately perpendicular to the coil axis, and the side surfaces of the spiral patterns SP1 to SP6 refer to surfaces that are approximately perpendicular to the radial direction.

The spiral patterns SP1 to SP6 are connected to each other through via holes formed in the insulating resin layers 71 to 75 to form a single coil conductor. The material of the conductor layers 10, 20, 30, 40, 50, and 60 is preferably copper (Cu). Of the insulating resin layers 70 to 76, at least the insulating resin layers 71 to 75 are made of a non-magnetic material. The insulating resin layer 70 located at the bottom layer and the insulating resin layer 76 located at the top layer may be magnetic.

The conductor layer 10 is the first conductor layer formed on the upper surface of the magnetic member M2 via an insulating resin layer 70, and as shown in FIG. 2, has a spiral pattern SP1 wound in a spiral shape with about three turns, and two electrode patterns 11 and 12. The lower surface of the spiral pattern SP1 is covered with the insulating resin layer 70, and the side and upper surfaces of the spiral pattern SP1 are covered with the insulating resin layer 71. As a result, the insulating resin layer 71 is interposed between the spiral pattern SP1 and the magnetic members M3 and M4. The electrode pattern 11 is connected to the outer peripheral end of the spiral pattern SP1. The electrode pattern 12 is provided independently of the spiral pattern SP1.

The conductor layer 20 is a second conductor layer formed on the upper surface of the conductor layer 10 via an insulating resin layer 71, and as shown in FIG. 3, has a spiral pattern SP2 wound in a spiral shape with about three turns, and two electrode patterns 21, 22. The lower surface of the spiral pattern SP2 is covered with the insulating resin layer 71, and the side and upper surfaces of the spiral pattern SP2 are covered with the insulating resin layer 72. As a result, the insulating resin layer 72 is interposed between the spiral pattern SP2 and the magnetic members M3, M4. Both the electrode patterns 21, 22 are provided independently of the spiral pattern SP2.

The conductor layer 30 is a third conductor layer formed on the upper surface of the conductor layer 20 via an insulating resin layer 72, and as shown in FIG. 4, has a spiral pattern SP3 wound in a spiral shape with about three turns, and two electrode patterns 31, 32. The lower surface of the spiral pattern SP3 is covered with an insulating resin layer 72, and the side and upper surfaces of the spiral pattern SP3 are covered with an insulating resin layer 73. As a result, the insulating resin layer 73 is interposed between the spiral pattern SP3 and the magnetic members M3, M4. Both the electrode patterns 31, 32 are provided independently of the spiral pattern SP3.

The conductor layer 40 is a fourth conductor layer formed on the upper surface of the conductor layer 30 via an insulating resin layer 73, and as shown in FIG. 3, has a spiral pattern SP4 wound in a spiral shape with about three turns, and two electrode patterns 41, 42. The lower surface of the spiral pattern SP4 is covered with an insulating resin layer 73, and the side and upper surfaces of the spiral pattern SP4 are covered with an insulating resin layer 74. As a result, the insulating resin layer 74 is interposed between the spiral pattern SP4 and the magnetic members M3, M4. Both the electrode patterns 41, 42 are provided independently of the spiral pattern SP4.

The conductor layer 50 is a fifth conductor layer formed on the upper surface of the conductor layer 40 via an insulating resin layer 74, and as shown in FIG. 4, has a spiral pattern SP5 wound in a spiral shape with about three turns, and two electrode patterns 51, 52. The lower surface of the spiral pattern SP5 is covered with an insulating resin layer 74, and the side and upper surfaces of the spiral pattern SP5 are covered with an insulating resin layer 75. As a result, the insulating resin layer 75 is interposed between the spiral pattern SP5 and the magnetic members M3, M4. Both the electrode patterns 51, 52 are provided independently of the spiral pattern SP5.

The conductor layer 60 is a sixth conductor layer formed on the upper surface of the conductor layer 50 via an insulating resin layer 75, and as shown in FIG. 5, has a spiral pattern SP6 wound in a spiral shape for about 2.5 turns, and two electrode patterns 61, 62. The lower surface of the spiral pattern SP6 is covered with an insulating resin layer 75, and the side and upper surfaces of the spiral pattern SP6 are covered with an insulating resin layer 76. As a result, the insulating resin layer 76 is interposed between the spiral pattern SP6 and the magnetic members M3, M4. The electrode pattern 62 is connected to the outer peripheral end of the spiral pattern SP6. The electrode pattern 61 is provided independently of the spiral pattern SP6.

The inner peripheral end of the spiral pattern SP1 and the inner peripheral end of the spiral pattern SP2 are connected through a via conductor 81 that is part of the conductor layer 20 and is provided through the insulating resin layer 71. The outer peripheral end of the spiral pattern SP2 and the outer peripheral end of the spiral pattern SP3 are connected through a via conductor 82 that is part of the conductor layer 30 and is provided through the insulating resin layer 72. The inner peripheral end of the spiral pattern SP3 and the inner peripheral end of the spiral pattern SP4 are connected through a via conductor 83 that is part of the conductor layer 40 and is provided through the insulating resin layer 73. The outer peripheral end of the spiral pattern SP4 and the outer peripheral end of the spiral pattern SP5 are connected through a via conductor 84 that is part of the conductor layer 50 and is provided through the insulating resin layer material 74. The inner peripheral end of the spiral pattern SP5 and the inner peripheral end of the spiral pattern SP6 are connected through a via conductor 85 that is part of the conductor layer 60 and is provided through the insulating resin layer 75. As a result, the spiral patterns SP1 to SP6 are connected in series to form a coil conductor consisting of multiple turns. Furthermore, the electrode patterns 11, 21, 31, 41, 51, and 61 are exposed from the magnetic members M1 to M4 and are used as one of the external terminals. The electrode patterns 12, 22, 32, 42, 52, and 62 are exposed from the magnetic members M1 to M4 and are used as the other of the external terminals.

As shown in FIG. 1, at least some of the insulating resin layers 70-76 have protrusions that protrude into the inner diameter region and the outer diameter region. The radial protrusion amount of the protrusions is not constant between the insulating resin layers 70-76, and some protrusions are long and some are short.

Figure 6 is a schematic cross-sectional view illustrating the shape of the protrusions provided on the insulating resin layers 70 to 76.

6, the insulating resin layers 70 to 75 have protruding portions 70a to 75a that protrude into the inner diameter region and the outer diameter region, respectively. Here, assuming that the radial protruding amounts of the protruding portions 71a to 75a are L1 to L5, respectively,
L1>L2>L3>L4>L5
That is, the protrusion amounts L1 to L5 of the insulating resin layers 71 to 75 located between the two conductor layers gradually become shorter from the lower layer to the upper layer, and the protrusion amount of the protrusion 75a of the insulating resin layer 75 is the shortest. The protrusion amount L0 of the protrusion 70a of the insulating resin layer 70 located in the lowermost layer may be approximately the same as the protrusion amount L1 of the protrusion 71a of the insulating resin layer 71. In the example shown in FIG. 6, the insulating resin layer 76 located in the uppermost layer does not have a protrusion, but the insulating resin layer 76 may also have a protrusion. In addition, the protrusion amount of the spiral patterns SP1 to SP6 into the inner diameter region and the protrusion amount of the spiral patterns SP1 to SP6 into the outer region may be the same as each other or may be different.

Figure 7 is a schematic cross-sectional view for explaining the shape of the protrusion according to the first modified example. In the example shown in Figure 7, no protrusion is provided on the insulating resin layers 74 and 75. In this way, it is not necessary for the protrusion to be present for some insulating resin layers located between two conductor layers.

Figure 8 is a schematic cross-sectional view for explaining the shape of the protrusion according to the second modified example. In the example shown in Figure 8, the protrusion amount L1 of the protrusion 71a provided on the insulating resin layer 71 is shortened and is shorter than at least the protrusion amount L2 of the protrusion 72a. In addition, no protrusion is provided on the insulating resin layer 70. In this way, it is not essential that the protrusion amounts L1 to L5 gradually become shorter from the lower layer to the upper layer, and the protrusion amount L1 of the protrusion 71a may be shorter than the protrusion amount L2 of the protrusion 72a.

In this way, in the coil component 1 according to this embodiment, the protrusion amounts L1 to L5 of the insulating resin layers 71 to 75 that protrude into the inner diameter region and outer diameter region of the spiral patterns SP1 to SP6 are partially shortened, and the volume of the magnetic members M3 and M4 that fill the inner diameter region and outer diameter region increases accordingly. This makes it possible to increase the inductance without increasing the chip size.

Next, a method for manufacturing the coil component 1 according to this embodiment will be described.

Figures 9 to 20 are process diagrams for explaining the manufacturing method of the coil component 1 according to this embodiment. The process diagrams shown in Figures 9 to 20 show a cross section corresponding to one coil component 1, but in reality, multiple coil components 1 can be produced simultaneously by using an aggregate substrate.

First, a support is prepared in which a metal foil 91 such as copper (Cu) is provided on the surface of a base material 90, and an insulating resin layer 70 and a seed layer S are formed on the surface of the metal foil 91 (Figure 9). Next, a resist pattern R is formed on the surface of the seed layer S (Figure 10). The resist pattern R is a negative pattern of the conductor layer 10. In this state, the seed layer S is grown by electrolytic plating to form the conductor layer 10 (Figure 11). At this time, a sacrificial pattern VP3 is formed in the inner diameter region of the spiral pattern SP1, and a sacrificial pattern VP4 is formed in the outer region of the spiral pattern SP1.

Next, after the resist pattern R is peeled off, the seed layer S exposed in the peeled portion of the resist pattern R is removed by etching (FIG. 12). As a result, the spiral pattern SP1 and the sacrificial patterns VP3 and VP4 are electrically separated by the spiral slit SL. Next, an insulating resin layer 71 and a metal foil 92 are formed on the surface of the conductor layer 10 so as to fill the slit SL (FIG. 13). The insulating resin layer 71 and the metal foil 92 can be formed by a lamination method. Next, the metal foil 92 is patterned to remove the metal foil 92 from the portion overlapping with the sacrificial patterns VP3 and VP4, and then the sacrificial patterns VP3 and VP4 are exposed by blast processing using the metal foil 92 as a mask (FIG. 14). Next, after removing the metal foil 92 (FIG. 15), an opening for forming a via conductor 81 (see FIG. 2) is formed in the insulating resin layer 71 by laser processing. Through the above steps, the formation of the conductor layer 10 and the insulating resin layer 71 is completed.

Then, the steps shown in Figures 9 to 15 are repeated to sequentially form conductor layer 20, insulating resin layer 72, conductor layer 30, insulating resin layer 73, conductor layer 40, insulating resin layer 74, conductor layer 50, insulating resin layer 75, conductor layer 60, and insulating resin layer 76 (Figure 16). In conductor layers 20, 30, 40, 50, and 60, the inner diameter regions of spiral patterns SP2 to SP6 also include sacrificial pattern VP3, and the outer regions of spiral patterns SP2 to SP6 include sacrificial pattern VP4. The sacrificial patterns VP3 and VP4 of conductor layer 60, which is located at the top layer, are exposed from an opening provided in insulating resin layer 76.

In this state, wet etching is performed to remove the sacrificial patterns VP3 and VP4 (Figure 17). The spiral patterns SP1 to SP6 are not etched because they are covered with the insulating resin layers 70 to 76. As a result, a space S3 is formed in the inner diameter region of the spiral patterns SP1 to SP6, and a space S4 is formed in the outer region of the spiral patterns SP1 to SP6. In addition, parts of the insulating resin layers 71 to 76 protrude into the spaces S3 and S4. At this point, there is no substantial difference in the amount of protrusion of the insulating resin layers 71 to 76 into the spaces S3 and S4.

Next, a laser beam 93 is applied to the insulating resin layer 70 exposed in the spaces S3 and S4 and to the insulating resin layers 71 to 76 protruding into the spaces S3 and S4, thereby removing a part of the exposed part of the insulating resin layer 70 and a part of the protruding parts of the insulating resin layers 71 to 76 (FIG. 18). At this time, the laser processing may be performed with the top surface of the insulating resin layer 76 covered with metal foil to prevent the top surface of the insulating resin layer 76 from being damaged. Alternatively, blast processing may be performed instead of the laser processing.

At this time, it is ideal to remove all of the insulating resin layers 70-76 exposed or protruding into the spaces S3 and S4, but in order to remove all of the insulating resin layers 70-76 exposed or protruding into the spaces S3 and S4, not only would a long processing time be required, but the damage to the parts of the insulating resin layers 70-76 that should not be removed would be large. For this reason, instead of removing all of the insulating resin layers 70-76 exposed or protruding into the spaces S3 and S4, as explained using Figures 6 and 7, the protruding parts are partially removed under conditions such that the protruding amount of the insulating resin layer located at the top is shorter. Depending on the conditions, the protruding amount of the insulating resin layer 71 in the lower layer will also be shorter, as explained using Figure 8. This is because the laser beam 93 reflected by the metal foil 91 is irradiated to the protruding part of the insulating resin layer 71. In this manner, in this embodiment, the insulating resin layers 70-76 that are exposed or protrude into the spaces S3 and S4 are partially removed by setting the conditions for the laser processing or blast processing so as not to cause significant damage to the portions of the insulating resin layers 70-76 that should not be removed.

Next, the magnetic members M3 and M4 are formed to fill the spaces S3 and S4, and the magnetic member M1 is formed to cover the insulating resin layer 76 (FIG. 19). The magnetic members M3 and M4 to be filled in the spaces S3 and S4 are pushed from the insulating resin layer 76 located in the upper layer to the insulating resin layer 70 located in the lower layer. As described with reference to FIGS. 6 to 8, the insulating resin layer located in the upper layer is processed so that the protrusion amount is shorter, so that the embedding work of the magnetic members M3 and M4 can be performed efficiently and voids where the magnetic members M3 and M4 do not exist in the spaces S3 and S4 are unlikely to occur. Next, the base material 90 and the metal foil 91 are removed (FIG. 20). Then, after forming the magnetic member M2 to cover the insulating resin layer 70, the coil component 1 according to this embodiment shown in FIG. 1 is completed by dicing into individual pieces.

In this manner, in this embodiment, after the spaces S3, S4 are formed by removing the sacrificial patterns VP3, VP4, parts of the insulating resin layers 70-76 exposed or protruding into the spaces S3, S4 are removed before the magnetic members M3, M4 are embedded in the spaces S3, S4. This allows the magnetic members M3, M4 to be embedded smoothly, and the volume of the magnetic members M3, M4 increases due to the expansion of the spaces S3, S4. Moreover, because the removal of the insulating resin layers 70-76 exposed or protruding into the spaces S3, S4 is limited to partial removal, no significant damage is inflicted on the parts of the insulating resin layers 70-76 that should not be removed.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention, and it goes without saying that these are also included within the scope of the present invention.

1 Coil components 10, 20, 30, 40, 50, 60 Conductor layers 11, 12, 21, 22, 31, 32, 41, 42, 51, 52, 61, 62 Electrode patterns 70 to 76 Insulating resin layers 70a to 75a Protrusions 81 to 85 Via conductors 90 Substrate 91 Metal foil 92 Metal foil 93 Laser beam C Coil patterns M1 to M4 Magnetic member R Resist pattern S Seed layers S3, S4 Space SL Slits SP1 to SP6 Spiral patterns VP3, VP4 Sacrificial pattern

Claims (5)

First and second magnetic members;
a plurality of conductor layers disposed between the first magnetic member and the second magnetic member, each of the conductor layers including a spiral pattern wound in a spiral shape;
A plurality of insulating resin layers provided between the plurality of conductor layers,
a third magnetic member embedded in an inner diameter region of the spiral pattern;
The insulating resin layers each have a first protruding portion protruding into the inner diameter region,
A coil component characterized in that the first protrusion of the insulating resin layer located at one end side in the coil axis direction among the plurality of insulating resin layers has a shorter protrusion amount than the first protrusion of the insulating resin layer located at the other end side in the coil axis direction among the plurality of insulating resin layers, thereby making the diameter of the inner diameter region in a region surrounded by the first protrusion of the insulating resin layer located at one end side larger than the diameter of the region surrounded by the first protrusion of the insulating resin layer located at the other end side . The coil component according to claim 1, characterized in that some of the first protrusions protrude longer from one end side to the other end side in the coil axial direction. The coil component according to claim 2, characterized in that the protrusion amount of the first protrusion portion of the insulating resin layer located on the one end side is shorter than the protrusion amount of the first protrusion portion of the insulating resin layer located second to the one end side in the coil axis direction among the plurality of insulating resin layers. a fourth magnetic member located in an outer region of the spiral pattern,
the insulating resin layers further have second protruding portions protruding into the outer region,
The coil component according to any one of claims 1 to 3, characterized in that the second protrusion of an insulating resin layer located at one end side in the coil axis direction among the plurality of insulating resin layers has a shorter protrusion amount than the second protrusion of at least one other insulating resin layer. A step of alternately laminating a plurality of conductor layers and a plurality of insulating resin layers, the conductor layers including a spiral pattern wound in a spiral shape and a sacrificial pattern located in an inner diameter region of the spiral pattern;
forming a space in an inner diameter region of the spiral pattern by removing the sacrificial pattern;
removing a part of the protruding portion made of the plurality of insulating resin layers protruding into the space;
and embedding a magnetic member in the space.

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