Coil component having terminal electrodes with high mounting strength, and electronic device including the coil component

Patent metadata

Field	Value
Publication number	US-2019122809-A1
Application number	US-201816222878-A
Country	US
Kind code	A1
Filing date	Dec 17, 2018
Priority date	Jul 29, 2014
Publication date	Apr 25, 2019
Grant date	—

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.

First claim

We/I claim:

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 parts of the metal magnetic grains along an interface between the underlying layer and the magnetic body, wherein the interface has resin-contacting areas where the underlying layer is in contact with the resin, and metal-contacting areas where the underlying layer is in contact with the metal parts of the metal magnetic gains, wherein the resin-contacting areas are concave toward the magnetic body with respect to the metal-contacting areas.

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, on a magnetic body surface where the terminal electrodes are not formed, phosphorus is contained at least in some areas of the surface.

10 . 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.

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

Assignees

• Taiyo Yuden Kk

Inventors

• Mimura Daiki
• Yagasaki Toshiyuki

Classifications

• H01F27/29 Primary

  Terminals; Tapping arrangements {for signal inductances} · CPC title

• H01F41/042

  by thin film techniques · CPC title

• H01F27/327

  Encapsulating or impregnating (encapsulating coil and core H01F27/022) · CPC title

• H01F41/046

  structurally combined with ferromagnetic material · CPC title

• H01F41/04

  for manufacturing coils {(coils for transformer or inductances H01F27/28)} · CPC title