Laminated inductor
A laminated inductor includes a laminate constituted by multiple magnetic material layers, and coil conductors formed in a spiral pattern in the laminate. The magnetic material layers are layers of a magnetic material having multiple metal grains constituted by a Fe—Si-M soft magnetic alloy and oxide film formed on the surface of the metal grains. The magnetic material has bonding portions where adjacent metal grains are bonded via the oxide film formed on the respective surfaces of the adjacent metal grains as well as bonding portions of metal grains bonding to each other in areas where no oxide film is present, and at least some of the voids generated by agglomeration of the metal grains are filled with a resin material.
1. A laminated inductor, comprising:
a laminate constituted by multiple magnetic material layers, and coil conductors formed in a spiral pattern in the laminate, where the coil conductors have conductive patterns formed on magnetic material layers, respectively, and via hole conductors that penetrate through the magnetic material layers and electrically connect multiple conductive patterns formed thereon;
wherein the magnetic material layers are layers of a magnetic material having multiple metal grains constituted by a Fe—Si-M soft magnetic alloy (where M is a metal element that oxidizes more easily than Fe) and oxide film formed on the surface of the metal grains and made of an oxide of the soft magnetic alloy, the magnetic material has bonding portions where adjacent metal grains are connected via the oxide film formed on the respective surfaces of the adjacent metal grains as well as bonding portions where metal grains are interconnected in areas where no oxide film is present, and voids where no metal grain nor oxide film is present are generated by agglomeration of the metal grains, wherein at least some of the voids are filled with a resin material.
2. A laminated inductor according to claim 1 , wherein the resin material is filled in at least 15% of the voids, which is a ratio of the area of voids filled with the resin material to the area of all the voids as observed on a cross section of the magnetic material layer.
3. A laminated inductor according to claim 1 , wherein the resin material is constituted by at least one type of resin selected from the group consisting of silicone resins, epoxy resins, phenol resins, silicate resins, urethane resins, imide resins, acrylic resins, polyester resins and polyethylene resins.
4. A laminated inductor according to claim 2 , wherein the resin material is constituted by at least one type of resin selected from the group consisting of silicone resins, epoxy resins, phenol resins, silicate resins, urethane resins, imide resins, acrylic resins, polyester resins and polyethylene resins.
5. A laminated inductor according to claim 1 , wherein M is Cr.
6. A laminated inductor according to claim 1 , wherein the voids filled with the resin material are continuous.