COIL COMPONENT, METHOD OF MANUFACTURING THE SAME, AND ELECTRONIC DEVICE

• US 20160035476A1
• Filed: 07/28/2015
• Published: 02/04/2016
• Est. Priority Date: 07/29/2014
• Status: Active Grant

• Current Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co)
• Original Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co)
• Inventors: YAGASAKI, Toshiyuki, MIMURA, Daiki
• Granted Patent: US 9,728,316 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 27/28 Coils; Windings; Conductive connections
• CPC Class Codes: H01F 27/29 Terminals; Tapping arrangements for signal inductances
• CPC Class Codes: H01F 27/327 Encapsulating or impregnating encapsulating coil and core H01F27/022
• CPC Class Codes: H01F 41/04 for manufacturing coils coils for transformer or inductances H01F27/28
• CPC Class Codes: H01F 41/042 by thin film techniques
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material

Abstract

A coil component includes an air-core coil embedded in a magnetic body constituted by resin and metal magnetic grains. Both ends of the coil are exposed on the surface of the magnetic body, and the side on which both ends are exposed is polished and etched to form terminal electrodes. To be specific, an underlying layer of metal material is formed across the surface of the magnetic body and the ends by means of sputtering, and then a cover layer is formed. Where the magnetic body contacts the underlying layer, the areas where the underlying layer is in contact with the resin ensure insulation, while the contact between the underlying layer and the exposed parts of the metal magnetic grains ensures adhesion, thus increasing the adhesion strength with respect to the terminal electrodes.

Claims

1. A coil component comprising an air-core coil embedded in a magnetic body constituted by resin and metal magnetic grains, and having terminal electrodes electrically connected to both ends of the coil, wherein:

both ends of the coil are exposed on a surface of the magnetic body;

the terminal electrodes are formed across the surface of the magnetic body and ends of the coil, and constituted by an underlying layer formed with metal material and a cover layer placed on an outer side of the underlying layer; and

the underlying layer is in contact with the resin and metal magnetic grains where the underlying layer is in contact with the magnetic body.

2. A coil component according to claim 1, wherein, where the underlying layer is in contact with the magnetic body, a ratio of areas where the underlying layer is in contact with the metal magnetic grains is greater than a ratio of areas where the underlying layer is not in contact with the metal magnetic grains.

3. A coil component according to claim 1, wherein the metal magnetic grains of the magnetic body include two or more types of metal magnetic grains of different grain sizes.

4. A coil component according to claim 1, wherein the metal material that forms the underlying layer contains one of Ag, Cu, Au, Al, Mg, W, Ni, Fe, Pt, Cr, and Ti.

5. A coil component according to claim 1, wherein the metal material that forms the underlying layer contains at least Ag or Cu.

6. A coil component according to claim 1, wherein the cover layer is formed with Ag or conductive resin containing Ag.

7. A coil component according to claim 1, wherein a protective layer covering an outer side of the cover layer is provided.

8. A coil component according to claim 7, wherein the protective layer is formed with Ni and Sn.

9. A coil component according to claim 1, wherein a magnetic body surface on a side where the terminal electrodes are formed contains less resin than a magnetic body surface on a side where the terminal electrodes are not formed.

10. A coil component according to claim 1, wherein, on a magnetic body surface where the terminal electrodes are not formed, phosphorus is contained at least in some areas of the surface.

11. A coil component according to claim 1, wherein, on a magnetic body surface where the terminal electrodes are not formed, at least some areas of the surface are covered with resin that contains an oxide filler whose grain size is smaller than that of the metal grains.

15. An electronic device having a coil component according to claim 1.

12. A method of manufacturing a coil component comprising:

a step to embed an air-core coil in complex magnetic material being a mixture of resin and metal magnetic grains, mold the magnetic material so that both ends of the coil are exposed on its surface,

and cure the resin in the molding, to obtain a magnetic body in which the coil is embedded;

a step to polish and etch a surface where the ends of the coil are exposed;

and a step to sputter metal material onto a surface etched in the previous step to form an underlying layer across a surface of the magnetic body and ends of the coil,

and then form a cover layer that covers an outer side of the underlying layer, to form terminal electrodes constituted by the underlying layer and cover layer.

13. A method of manufacturing a coil component according to claim 12, further comprising a step to form a protective layer that covers the cover layer.

14. A coil component formed by a manufacturing method according to claim 12, wherein the underlying layer is in contact with the resin and metal magnetic grains where it is in contact with the magnetic body.