US 12,274,005 B2
Coil component and electronic device
Osamu Takahashi, Takasaki (JP); and Yasuyuki Taki, Takasaki (JP)
Assigned to TAIYO YUDEN CO., LTD, Tokyo (JP)
Filed by TAIYO YUDEN CO., LTD., Tokyo (JP)
Filed on Mar. 17, 2021, as Appl. No. 17/204,841.
Claims priority of application No. 2020-064502 (JP), filed on Mar. 31, 2020.
Prior Publication US 2021/0304950 A1, Sep. 30, 2021
Int. Cl. H05K 1/18 (2006.01); H01F 27/28 (2006.01); H01F 27/29 (2006.01); H01F 41/04 (2006.01)
CPC H05K 1/181 (2013.01) [H01F 27/2804 (2013.01); H01F 27/292 (2013.01); H01F 41/043 (2013.01); H01F 2027/2809 (2013.01); H05K 2201/1003 (2013.01); Y10T 428/32 (2015.01)] 7 Claims
OG exemplary drawing
 
1. A coil component comprising:
a substrate body containing: metal magnetic grains whose primary component is iron and which contains silicon and a metal that oxidizes more easily than iron; and an oxide layer covering surfaces of the metal magnetic grains and joining multiple numbers of the metal magnetic grains together;
a coil conductor provided in the substrate body;
external electrodes provided on a surface of the substrate body and electrically connected to the coil conductor; and
a bonding part located between, as an adhesive, and bonding the metal magnetic grains and the external electrodes, wherein a concentration of iron decreases continuously in a range of 80 percent or more of a thickness of the bonding part from an interface region with the metal magnetic grains to an interface region with the external electrodes,
wherein the bonding part between the metal magnetic grains and the external electrodes is such that a concentration by weight of the metal that oxidizes more easily than iron is lower than a concentration by weight of iron, but higher than a concentration by weight of oxygen, throughout the bonding part in a thickness direction entirely from the interface region with the metal magnetic grains to the interface region with the external electrodes.