CROSS REFERENCE TO RELATED APPLICATION

This application claims benefit of priority to Japanese Patent Application 2017-143636 filed Jul. 25, 2017, the entire content of which is incorporated herein by reference.

BACKGROUND

Technical Field

The present disclosure relates to a coil component and a method of manufacturing the same.

Background Art

A conventional coil component is described in Japanese Laid-Open Patent Publication No. 2015-133523. This coil component has a spiral first coil conductor layer, an insulating layer laminated on the first coil conductor layer, and a spiral second coil conductor layer laminated on the insulating layer. A lead-out conductor is led radially outward from an outer-circumferential end of the first coil conductor layer, and the lead-out conductor is connected to an electrode. The first coil conductor layer and the second coil conductor layer overlap with each other when viewed is a lamination direction. The lead-out conductor intersects with the second coil conductor layer when viewed in the lamination direction. The second coil conductor layer overlaps with a connecting portion of the lead-out conductor connected to the first coil conductor layer when viewed in the lamination direction.

SUMMARY

Reductions in size and height of coil components are recently desired, and it has been discovered that a new problem occurs in the reductions in size and height of the conventional coil component as described above.

More specifically, since the reductions in size and height result in reductions in wiring interval in the coil conductor layers and distance between the first and second coil conductor layers, reflected light (exposure light) from a lower layer of the second coil conductor layer is not negligible when the second coil conductor layer is manufactured by photolithography. Since the reductions in size and height also result in reductions in line width and film thickness of the coil conductor layers, thinning due to poor exposure may have a significant influence on characteristics, or breaking may occur.

The present disclosure provides a coil component and a method of manufacturing the same capable of reducing thinning or disconnection of a coil conductor layer overlapping with a lead-out conductor when viewed in a lamination direction.

A coil component of an aspect of the present disclosure comprises a first coil conductor layer wound on a plane; a lead-out conductor led out on the same plane as the coil conductor layer from an outer-circumferential end of the first coil conductor layer; an insulating layer laminated on the first coil conductor layer and the lead-out conductor; and a second coil conductor layer laminated on the insulating layer and wound on a plane. The first coil conductor layer and the second coil conductor layer concentrically overlap with each other when viewed in a lamination direction. The lead-out conductor has a connecting portion connected to the first coil conductor layer and provided with a coil extension part extending to overlap with the second coil conductor layer when viewed in the lamination direction.

According to the coil component, since the lead-out conductor has the connecting portion connected to the first coil conductor layer and provided with the coil extension part, the coil extension part overlaps with the second coil conductor layer at a portion adjacent to a portion overlapping with the connecting portion of the lead-out conductor when viewed in the lamination direction. Therefore, when the second coil conductor layer is manufactured by photolithography, the occurrence of thinning or disconnection can be reduced in the second coil conductor layer at a portion adjacent to a portion overlapping with the connecting portion of the lead-out conductor.

In an embodiment of the coil component, the coil component has a first dummy conductor layer wound on the same plane as the first coil conductor layer on the outside of the first coil conductor layer without being electrically connected to the first coil conductor layer, and a second dummy conductor layer wound on the same plane as the second coil conductor layer on the outside of the second coil conductor layer without being electrically connected to the second coil conductor layer. The first dummy conductor layer and the second dummy conductor layer concentrically overlap with each other when viewed in the lamination direction. When viewed in the lamination direction, the lead-out conductor has an intersecting portion intersecting with the second dummy conductor layer and provided with a dummy extension part extending to overlap with the second dummy conductor layer.

According to the embodiment, when the second dummy conductor layer is manufactured by photolithography, the occurrence of thinning or disconnection can be reduced in the second dummy conductor layer at a portion adjacent to a portion overlapping with the intersecting portion of the lead-out conductor.

In an embodiment of the coil component, the coil component comprises a first coil conductor layer wound on a plane; a lead-out conductor led out on the same plane as the coil conductor layer from an outer-circumferential end of the first coil conductor layer; and an insulating layer laminated on the first coil conductor layer and the lead-out conductor. The coil component further comprises a second coil conductor layer laminated on the insulating layer and wound on a plane; a first dummy conductor layer wound on the same plane as the first coil conductor layer on the outside of the first coil conductor layer without being electrically connected to the first coil conductor layer; and a second dummy conductor layer wound on the same plane as the second coil conductor layer on the outside of the second coil conductor layer without being electrically connected to the second coil conductor layer. The first coil conductor layer and the second coil conductor layer concentrically overlap with each other when viewed in a lamination direction. The first dummy conductor layer and the second dummy conductor layer concentrically overlap with each other when viewed in the lamination direction, and when viewed in the lamination direction, the lead-out conductor has an intersecting portion intersecting with the second dummy conductor layer and provided with a dummy extension part extending to overlap with the second dummy conductor layer.

According to the embodiment, when the second dummy conductor layer is manufactured by photolithography, the occurrence of thinning or disconnection can be reduced in the second dummy conductor layer at a portion adjacent to a portion overlapping with the intersecting portion of the lead-out conductor.

In an embodiment of the coil component, the coil component has an electrode connected to the lead-out conductor, the lead-out conductor has a lead-out part extending from an outer circumferential end of the first coil conductor layer to the electrode, and the lead-out part is orthogonal to the outer circumferential end of the first coil conductor layer when viewed from the lamination direction.

According to the embodiment, since the lead-out conductor is orthogonal to the outer circumferential end of the first coil conductor layer when viewed from the lamination direction, when the second coil conductor layer is manufactured by photolithography, the occurrence of thinning or disconnection can further be reduced in the second coil conductor layer at a portion adjacent to a portion overlapping with the connecting portion of the lead-out conductor.

In an embodiment of the coil component, the first coil conductor layer has a thickness of 5 μm or more and 15 μm or less (i.e., from 5 μm to 15 μm).

According to the above embodiment, the first coil conductor layer has a thickness of 5 μm or more and 15 μm or less (i.e., from 5 μm to 15 μm), and the thickness of the first coil conductor layer is large; however, since the coil extension part is disposed, the occurrence of thinning or disconnection can be reduced in the second coil conductor layer.

In an embodiment of the coil component, the second coil conductor layer has an aspect ratio of 1 or more and 2.5 or less (i.e., from 1 to 2.5).

According to the embodiment, since the second coil conductor layer has an aspect ratio of 1 or more and 2.5 or less (i.e., from 1 to 2.5), the second coil conductor layer is manufactured by photolithography; however, since the coil extension part is disposed, the occurrence of thinning or disconnection can be reduced in the second coil conductor layer.

A method of manufacturing a coil component according to an aspect of the present disclosure comprises the steps of disposing a first coil conductor layer wound on a plane and a lead-out conductor led out on the same plane as the coil conductor layer from an outer-circumferential end of the first coil conductor layer to the outside and disposing a coil extension part extending along a winding shape of the first coil conductor layer at a connecting portion of the lead-out conductor connected to the first coil conductor layer; laminating an insulating layer on the first coil conductor layer and the lead-out conductor; and disposing a photoresist on the insulating layer. The method further comprises exposing the photoresist after a light shield is placed at positions overlapping with the first coil conductor layer and the coil extension part when viewed in the lamination direction; removing a portion not exposed due to the mask; and disposing a second coil conductor layer in the removed portion of the photoresist.

According to the manufacturing method of the coil component, the second coil conductor layer overlaps with the first coil conductor layer and the coil extension part when viewed in the lamination direction. Therefore, the coil extension part overlaps with the second coil conductor layer at a portion adjacent to a portion overlapping with the connecting portion of the lead-out conductor when viewed in the lamination direction. Therefore, when the second coil conductor layer is manufactured by photolithography, the occurrence of thinning or disconnection can be reduced in the second coil conductor layer at a portion adjacent to a portion overlapping with the connecting portion of the lead-out conductor.

The coil component and the method of manufacturing the same of the present disclosure can reduce occurrence of thinning or disconnection of the coil conductor layer overlapping with the lead-out conductor when viewed in the lamination direction.

