Common mode noise filter and production method therefor

摘要

A common mode noise filter includes a first insulating layer, a first coil conductor on an upper surface of the first insulating layer, a second coil conductor on a lower surface of the first insulating layer, a second insulating layer on the upper surface of the first insulating layer to cover the first coil conductor, a third insulating layer on a lower surface of the second insulating layer to cover the second coil conductor. The first insulating layer contains glass and inorganic filler, and contains pores dispersed therein. The second insulating layer covers the first coil conductor, contains glass and inorganic filler, and contains pores dispersed therein. The third insulating layer covers the second coil conductor, contains glass and inorganic filler, and contains pores dispersed therein. This common mode noise filter has excellent high-frequency characteristics at a high yield rate.

主权项

1. A common mode noise filter comprising:
a first insulating layer containing glass and inorganic filler, the first insulating layer containing a plurality of pores dispersed therein; a first coil conductor disposed on an upper surface of the first insulating layer; a second coil conductor disposed on a lower surface of the first insulating layer, the second coil conductor facing the first coil conductor across the first insulating layer; a second insulating layer disposed on the upper surface of the first insulating layer to cover the first coil conductor, the second insulating layer containing glass and inorganic filler, the second insulating layer containing a plurality of pores dispersed therein; a third insulating layer disposed on the lower surface of the second insulating layer to cover the second coil conductor, the third insulating layer containing glass and inorganic filler, third insulating layer containing a plurality of pores dispersed therein; a first magnetic oxide layer disposed above an upper surface of the second insulating layer; and a second magnetic oxide layer disposed below a lower surface of the third insulating layer such that the first insulating layer, the second insulating layer, and the third insulating layer are provided between the first magnetic oxide layer and the second magnetic oxide layer, wherein: the first insulating layer includes a portion provided between the first coil conductor and the second coil conductor, an entire lower surface of the first coil conductor and an entire upper surface of the second coil conductor contact the portion of the first insulating layer, a pore ratio, which is a ratio of a total volume of the plurality of pores to a volume of the portion of the first insulating layer, ranges from 5 to 40 vol. %, and the pores in the first insulating layer are only independent closed pores.