LAMINATED INDUCTOR, METHOD FOR MANUFACTURING THE LAMINATED INDUCTOR, AND LAMINATED CHOKE COIL

• US 20110133881A1
• Filed: 07/30/2009
• Published: 06/09/2011
• Est. Priority Date: 07/30/2008
• Status: Active Grant

• Current Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co)
• Original Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co)
• Inventors: Amamiya, Yoshie, Noro, Yukihiro, Okabe, Kenji, Nakajima, Takashi, Kamiyama, Yoshiaki, Kobayashi, Tomomi
• Granted Patent: US 8,587,400 B2
• Time in Patent Office: Days
• US Class Current: 336/200
• CPC Class Codes: H01F 17/0013 with stacked layers
• CPC Class Codes: H01F 17/04 with magnetic core
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material

Abstract

Disclosed is a laminated inductor that has good direct current superimposition characteristics, does not cause a variation in temperature characteristics, suppresses the occurrence of delamination, and can be stably manufactured. Also disclosed are a method for manufacturing the laminated inductor and a laminated choke coil. A laminated inductor (10) for use as a choke coil in a power supply circuit includes a rectangular parallelepiped-shaped laminated chip (1) and at least one pair of external electrodes (8) that are provided at the end of the laminated chip (1) and are conductively connected to the end of a coil. The laminated chip (1) includes a plurality of magnetic material layers (3) formed of an Ni—Zn—Cu ferrite, a plurality of conductive layers (2), which are laminated through the magnetic material layers (3) to constitute a coil, and at least one nonmagnetic layer (4) formed of a Ti—Ni—Cu—Mn—Zr—Ag-base dielectric material and formed in contact with a plurality of the magnetic material layers (3).

Claims

1. A laminated inductor used as a choke coil in power supply circuits, characterized by comprising:

a rectangular parallelepiped-shaped laminated chip, having a plurality of magnetic material layers constituted by Ni—

Zn—

Cu ferrite, a plurality of conductive layers that are laminated via the magnetic material layers to constitute a coil, and at least one nonmagnetic layer constituted by Ti—

Ni—

Cu—

Mn—

Zr—

Ag dielectric and formed in a manner contacting a plurality of the magnetic material layers; and

at least one pair of external electrodes provided at ends of the laminated chip and electrically connected to ends of the coil.

2. A laminated inductor according to claim 1, characterized in that the laminated chip has a bonded interface where the Ni—

Zn—

Cu ferrite of the magnetic material layer and Ti—

Ni—

Cu—

Mn—

Zr—

Ag dielectric of the nonmagnetic layer are inter-diffused.

3. A laminated inductor according to claim 1, characterized in that the nonmagnetic layer is constituted by a dielectric whose main component is TiO₂ and which also contains NiO, CuO, Mn₃O₄, ZrO₂ and Ag₂O or Ag.

4. A laminated inductor according to claim 3, characterized in that the dielectric contains TiO₂, 2.0 to 15 percent by weight of NiO, 1.5 to 6.0 percent by weight of CuO, 0.2 to 20 percent by weight of Mn₃O₄, 0.1 to 10 percent by weight of ZrO₂, and 0.01 to 10 percent by weight of Ag₂O, based on equivalent oxide, to a total percentage by weight of 100.

10. A laminated inductor according to claim 2, characterized in that the nonmagnetic layer is constituted by a dielectric whose main component is TiO₂ and which also contains NiO, CuO, Mn₃O₄, ZrO₂ and Ag₂O or Ag.

13. A laminated inductor according to claim 1, wherein the Ni—

Zn—

Cu ferrite is constituted solely by Fe₂O₃, NiO, ZnO and CuO, and the Ti—

Ni—

Cu—

Mn—

Zr—

Ag dielectric is constituted solely by TiO₂, NiO, CuO, Mn₃O₄, ZrO₂ and Ag₂O or Ag.

5. A method of manufacturing a laminated inductor, characterized by comprising:

a step to prepare ferrite powder paste containing Fe₂O₃, NiO, ZnO and CuO;

a step to prepare dielectric powder paste whose main component is TiO₂ and which also contains NiO, CuO, Mn₃O₄, ZrO₂ and Ag₂O or Ag;

a step to form magnetic sheets by coating the ferrite powder paste and print conductive paste patterns on the magnetic sheets, and then pressure-bond these layers to form a laminate in a manner allowing the conductive paste patterns of vertically adjacent magnetic sheets to be connected via through holes to form a helical coil, and also in a manner causing at least one nonmagnetic sheet formed by coating the dielectric powder paste or nonmagnetic pattern formed by printing the nonmagnetic powder paste to be inserted therebetween; and

a step to sinter the laminate to obtain a laminated chip.

7. A method of manufacturing a laminated inductor according to claim 5, characterized in that the step to sinter the laminate to obtain a laminated chip is such that Ni—

Zn—

Cu ferrite constituting the magnetic sheet is inter-diffused with Ti—

Ni—

Cu—

Mn—

Zr—

Ag dielectric constituting the nonmagnetic sheet to form a bonded interface.

8. A method of manufacturing a laminated inductor according to claim 5, characterized in that the dielectric powder is constituted by blending TiO₂ with 2.0 to 15 percent by weight of NiO, 1.5 to 6.0 percent by weight of CuO, 0.2 to 20 percent by weight of Mn₃O₄, 0.1 to 10 percent by weight of ZrO₂, and 0.01 to 10 percent by weight of Ag₂O, based on equivalent oxide, to a total percentage by weight of 100.

14. A method of manufacturing a laminated inductor according to claim 5, wherein each magnetic layer is constituted solely by Fe₂O₃, NiO, ZnO and CuO, and each nonmagnetic layer is constituted solely by TiO₂, NiO, CuO, Mn₃O₄, ZrO₂ and Ag₂O or Ag.

6. A method of manufacturing a laminated inductor, characterized by comprising:

a step to prepare ferrite powder paste containing Fe₂O₃, NiO, ZnO and CuO;

a step to prepare dielectric powder paste whose main component is TiO₂ and which also contains NiO, CuO, Mn₃O₄, ZrO₂ and Ag₂O or Ag;

a step to form magnetic sheets by coating the ferrite powder paste and print conductive paste patterns on the magnetic sheets, and also print magnetic paste patterns using the ferrite powder paste, alternately in such a way that at least one nonmagnetic pattern formed by printing the dielectric powder paste is inserted therebetween, to obtain a laminate; and

a step to sinter the laminate to obtain a laminated chip.

11. A method of manufacturing a laminated inductor according to claim 6, characterized in that the step to sinter the laminate to obtain a laminated chip is such that Ni—

Zn—

Cu ferrite constituting each magnetic material layer formed by the magnetic paste pattern is inter-diffused with Ti—

Ni—

Cu—

Mn—

Zr—

Ag dielectric constituting each nonmagnetic layer formed by the nonmagnetic pattern to form a bonded interface.

12. A method of manufacturing a laminated inductor according to claim 6, characterized in that the dielectric powder is constituted by blending Ti_O2 with 2.0 to 15 percent by weight of NiO, 1.5 to 6.0 percent by weight of CuO, 0.2 to 20 percent by weight of M_n3O4, 0.1 to 10 percent by weight of Zr_O2, and 0.01 to 10 percent by weight of A_g2O, based on equivalent oxide, to a total percentage by weight of 100.

15. A method of manufacturing a laminated inductor according to claim 6, wherein each magnetic layer is constituted solely by Fe₂O₃, NiO, ZnO and CuO, and each nonmagnetic layer formed by the nonmagnetic pattern is constituted solely by TiO₂, NiO, CuO, Mn₃O₄, ZrO₂ and Ag₂O or Ag.

9. A laminated choke coil, characterized by having a coil conductor formation region where conductive layers constituting a coil are laminated alternately with magnetic material layers with at least one nonmagnetic layer inserted therebetween, and a yoke region constituted by magnetic material layers that are positioned at the top and bottom in the direction of lamination and serve as a yoke to connect magnetic fluxes formed on an inner side of the coil and magnetic fluxes formed on an outer side of the coil, wherein the magnetic material layer is constituted by Ni—

Zn—

Cu ferrite and the nonmagnetic layer, by Ti—

Ni—

Cu—

Mn—

Zr—

Ag dielectric.

16. A laminated inductor according to claim 9, wherein the Ni—

Zn—

Cu ferrite is constituted solely by Fe₂O₃, NiO, ZnO and CuO, and the Ti—

Ni—

Cu—

Mn—

Zr—

Ag dielectric is constituted solely by TiO₂, NiO, CuO, Mn₃O₄, ZrO₂ and Ag₂O or Ag.