Inductor and electric power supply using it

• US 20070257761A1
• Filed: 05/08/2006
• Published: 11/08/2007
• Est. Priority Date: 05/08/2006
• Status: Active Grant

• Current Assignee: Ibiden Co., Ltd.
• Original Assignee: Ibiden Co., Ltd.
• Inventors: Kato, Shinobu, Kariya, Takashi, Mano, Yasuhiko
• Granted Patent: US 7,843,302 B2
• Time in Patent Office: Days
• US Class Current: 336/200
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 17/06 with core substantially closed in itself, e.g. toroid
• CPC Class Codes: H01F 2017/002 Details of via holes for interconnecting the layers
• CPC Class Codes: H01F 2017/065 Core mounted around conductor to absorb noise, e.g. EMI filter
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/16235 the bump connector connecting to a via metallisation of the item
• CPC Class Codes: H01L 23/645 Inductive arrangements H01L23/647, H01L23/66 take precedence
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01087 Francium [Fr]
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/15312 being a pin array, e.g. PGA
• CPC Class Codes: H01L 2924/1532 the connection portion being formed on the die mounting surface of the substrate
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H05K 1/0233 : Filters, inductors or a magnetic substance
• CPC Class Codes: H05K 1/115 : Via connections; Lands around holes or via connections H05K1/112 takes precedence
• CPC Class Codes: H05K 1/185 : Components encapsulated in the insulating substrate of the printed circuit or incorporated in internal layers of a multilayer circuit semiconductor chips encapsulated by interconnect and support structures H01L23/5389, H01L24/00
• CPC Class Codes: H05K 2201/086 : for inductive purposes, e.g. printed inductor with ferrite core
• CPC Class Codes: H05K 2201/09581 : Applying an insulating coating on the walls of holes
• CPC Class Codes: H05K 3/4046 : using auxiliary conductive elements, e.g. metallic spheres, eyelets, pieces of wire
• CPC Class Codes: H05K 3/42 : Plated through-holes or plated via connections
• CPC Class Codes: H05K 3/4602 : characterized by a special circuit board as base or central core whereon additional circuit layers are built or additional circuit boards are laminated
• CPC Class Codes: Y10T 29/4902 : Electromagnet, transformer or inductor

Abstract

An inductor embedded in a printed wiring board includes a conductor extending in the thickness direction of a printed circuit board and a magnetic body that is in contact with the conductor with no gap therebetween. For example, the magnetic body is composed of ferrite having a cylindrical tubular shape. The conductor is composed of a copper film formed by plating on an inner peripheral surface of the cylindrical tubular ferrite. The inductor is inserted in the thickness direction of the printed wiring board.

Claims

1. An inductor constituting a part of a power supply circuit, comprising:

a magnetic body having a through-hole; and

a conductor provided on an inner surface of the through-hole.

2. The inductor according to claim 1, wherein the conductor is composed of copper.

3. The inductor according to claim 1, wherein the conductor is composed of copper and has a substantially cylindrical shape.

4. The inductor according to claim 1, wherein the conductor is composed of copper and has a substantially hollow cylindrical shape.

5. The inductor according to claim 1, wherein the magnetic body is of a shape such that the magnetic body substantially surrounds the conductor.

6. The inductor according to claim 1, wherein the magnetic body is composed of ferrite.

7. The inductor according to claim 1, wherein the magnetic body is composed of a composite material containing a magnetic material and a nonmagnetic material.

8. The inductor according to claim 1, wherein the magnetic body is composed of a composite material containing a magnetic powder and a resin.

9. The inductor according to claim 1, wherein the magnetic body is composed of a composite material containing a carbonyl iron powder and a resin.

10. The inductor according to claim 1, further comprising:

a dielectric material,

wherein the dielectric material is of a shape such that the dielectric material substantially surrounds the magnetic body.

11. An inductor embedded in a printed wiring board, comprising:

a magnetic body that extends in the thickness direction of the printed wiring board and that has a through-hole; and

a conductor provided on the inner surface of the through-hole.

12. The inductor embedded in a printed wiring board according to claim 11, wherein the conductor is composed of copper.

13. The inductor embedded in a printed wiring board according to claim 11, wherein the conductor is composed of copper and has a substantially cylindrical shape.

14. The inductor embedded in a printed wiring board according to claim 11, wherein the conductor is composed of copper and has a substantially hollow cylindrical shape.

15. The inductor embedded in a printed wiring board according to claim 11, wherein the magnetic body surrounds the side face of the conductor.

16. The inductor embedded in a printed wiring board according to claim 11, wherein the magnetic body is composed of ferrite.

17. The inductor embedded in a printed wiring board according to claim 11, wherein the magnetic body is composed of a composite material containing a magnetic material and a nonmagnetic material.

18. The inductor embedded in a printed wiring board according to claim 11, wherein the magnetic body is composed of a composite material containing a magnetic powder and a resin.

19. The inductor embedded in a printed wiring board according to claim 11, wherein the magnetic body is composed of a composite material containing a carbonyl iron powder and a resin.

20. The inductor embedded in a printed wiring board according to claim 11, further comprising:

a dielectric material,

wherein the dielectric material surrounds the side face of the magnetic body.

21. The inductor embedded in a printed wiring board according to claim 11, further comprising:

a dielectric material,

wherein the dielectric material is composed of an under-fill material having low thermal expansion characteristics.

22. An electronic device comprising:

a board; and

a power supply circuit that is provided in the board and that supplies a semiconductor device with power, wherein the power supply circuit includes at least an inductor formed in the thickness direction of the board.

23. The electronic device according to claim 22, wherein the power supply circuit includes:

a thin-film capacitor formed in the direction parallel to the principal surface of the board;

an inductor formed in the thickness direction of the board; and

a power supply IC device mounted on a surface of the board, the surface being opposite to a surface on which the semiconductor device is mounted.

24. The electronic device according to claim 22, wherein the power supply circuit includes:

a thin-film capacitor formed in the direction parallel to the principal surface of the board;

an inductor formed in the thickness direction of the board; and

a power supply IC device mounted on a surface of the board, the surface being opposite to a surface on which the semiconductor device is mounted;

wherein the thin-film capacitor, the inductor embedded in the board, and the power supply IC device are disposed close to the semiconductor device, and the power supply circuit and the semiconductor device are connected to each other with a short conductive circuit.

25. The electronic device according to claim 22, wherein the inductor includes a magnetic body that extends in the thickness direction of the board and that has a through-hole, and a conductor formed on the inner surface of the through-hole.

26. The electronic device according to claim 22, wherein a plurality of sets of the power supply circuits are provided in the board.

27. A method of producing an inductor comprising the steps of:

providing a magnetic body extending along a longitudinal axis,

forming a though-hole in the axial direction of the magnetic body, and

performing metal plating on an inner surface of the though-hole.

28. The method of producing an inductor according to claim 27, wherein the metal plating is copper plating.

29. The method of producing an inductor according to claim 27, wherein the magnetic body is composed of ferrite.

30. The method of producing an inductor according to claim 27, wherein the magnetic body is composed of a composite material containing a magnetic material and a nonmagnetic material.

31. A method of embedding an inductor in a board, comprising the steps of:

preparing an inductor that is made by preparing a longitudinally extending magnetic body and by performing metal plating on an inner surface of a through-hole formed in the axial direction of the magnetic body;

forming a through-hole through the board;

inserting the inductor into the through-hole; and

filling a space between the inductor and the board with a resin to fix the inductor to the board.

32. The method of embedding an inductor in a board according to claim 31, further comprising the step of:

filling the through-hole of the inductor with a resin.

33. The method of embedding in a board in a substrate according to claim 31, wherein both ends of the through-hole of the inductor are covered with a metal.

34. The method of embedding an inductor in a board according to claim 31, further comprising the step of:

after the inductor is fixed to the board, performing copper plating on the board and on the inner surface of the through-hole of the inductor; and

patterning a copper film.

35. A method of embedding an inductor in a board, comprising the steps of:

preparing a hollow cylindrical magnetic body;

forming a through-hole through a board;

inserting the magnetic body into the through-hole;

filling a space between the inductor and the board with a resin to fix the inductor to the substrate;

performing copper plating on the surface of the board and on an inner surface of the through-hole of the magnetic body; and

patterning the copper film.

36. The method of embedding an inductor in a board according to claim 35, further comprising the step of:

filling the through-hole of the inductor with a resin.