Flat magnetic element and power IC package using the same

• US 7,821,371 B2
• Filed: 10/26/2006
• Issued: 10/26/2010
• Est. Priority Date: 11/01/2005
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Materials Company Limited (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Materials Company Limited (Toshiba Corporation)
• Inventors: Sato, Akira, Inoue, Tetsuo, Nakagawa, Katsutoshi
• Primary Examiner(s): Enad; Elvin G
• Assistant Examiner(s): LIAN, MANG TIN BIK
• Application Number:
  US12/092,092
• Publication Number:
  US 20090243780A1
• Time in Patent Office: 1,461 Days
• Field of Search: None
• US Class Current: 336/200
• CPC Class Codes: H01F 1/15366 using a binder
• CPC Class Codes: H01F 1/26 by macromolecular organic substances
• CPC Class Codes: H01F 1/37 in a bonding agent
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 17/04 with magnetic core
• CPC Class Codes: H01F 2017/0066 with a magnetic layer
• CPC Class Codes: H01F 2017/0073 with a special conductive pattern, e.g. flat spiral
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 23/645 Inductive arrangements H01L23/647, H01L23/66 take precedence
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 25/165 Containers
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01021 Scandium [Sc]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/19104 : on the semiconductor or solid-state device, i.e. passive-on-chip
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H01L 2924/30107 : Inductance
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: Y10S 428/928 : Magnetic property
• CPC Class Codes: Y10T 428/29 : Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof

Abstract

A planar magnetic device 1 including a first magnetic layer 3, a second magnetic layer 5, and a planar coil 4 disposed between the first magnetic layer 3 and the second magnetic layer 5, wherein magnetic particles 7 having a shape ratio S/L of 0.7 to 1 when a length of a long axis is L and a length of a short axis orthogonal to the long axis is L are filled in a gap W between coil wirings of the planar coil 4. According to the planar magnetic device 1, it is possible to realize a planar magnetic device such as an inductor reduced in height by using fine particles that enable to effectively obtain a large inductance value.

Claims

1. A planar magnetic device comprising:

a first magnetic layer,

a second magnetic layer, and

a planar coil disposed between the first magnetic layer and the second magnetic layer,

wherein

magnetic particles, having a shape ratio S/L of 0.7 to 1 where a length of a long axis is L and a length of a short axis orthogonal to the long axis is S, fill a gap between coil wirings of the planar coil, the gap between the coil wirings of the planar coil being W, where W is 200 μ

m or less;

an average particle diameter of the magnetic particles is W/2 or less;

a thickness of the planar magnetic device is 0.5 mm or less; and

a filling ratio of the magnetic particles filled in the gap between the coil wirings of the planar coil is 30 vol. % or more.

2. The planar magnetic device according to claim 1, wherein the filling ratio of the magnetic particles filled in the gap between the coil wirings of the planar coil is 50 vol. % or more.

3. The planar magnetic device according to claim 1, wherein the magnetic particles are made from at least one of an amorphous alloy, a crystalline soft magnetic alloy, and ferrite.

4. The planar magnetic device according to claim 1, wherein the first magnetic layer and the second magnetic layer are made from a mixture of a magnetic powder and a resin.

5. The planar magnetic device according to claim 1, wherein the planar coil is made from a mixture of a metal powder and a resin.

6. The planar magnetic device according to claim 1, wherein the magnetic particles are a magnetic mixture containing 20 mass % or less of a resin binder.

7. The planar magnetic device according to claim 1, wherein a resin binder is dried after a magnetic layer is formed by filling the magnetic particles in the gap between the coil wirings and in a state where the resin binder penetrates into the magnetic particles, and a content of the resin binder in the dried magnetic layer is 0 to 20 mass %.

8. A power source IC package using the planar magnetic device according to any one of claims 1, 2-4, 5 and 6.

9. The power source IC package according to claim 8, wherein the power source IC package is an IC-integrated type.

10. The planar magnetic device according to claim 1, wherein the magnetic particles are a magnetic mixture containing 2 mass % or less of a resin binder.

11. The planar magnetic device according to claim 1, wherein a resin binder is dried after a magnetic layer is formed by filling the magnetic particles in the gap between the coil wirings and in a state where the resin binder penetrates into the magnetic particles, and a content of the resin binder in the dried magnetic layer is 0 to 2 mass %.