Method of forming a magnetic device having a conductive clip

• US 8,631,560 B2
• Filed: 10/05/2005
• Issued: 01/21/2014
• Est. Priority Date: 10/05/2005
• Status: Active Grant

• Current Assignee: Altera Corporation (Intel Corporation)
• Original Assignee: Enpirion, Inc. (MediaTek, Inc.)
• Inventors: Lotfi, Ashraf W., Wilkowski, Mathew A., Liakopoulos, Trifon M., Weld, John D.
• Primary Examiner(s): Tugbang, A. Dexter
• Application Number:
  US11/243,537
• Publication Number:
  US 20070075815A1
• Time in Patent Office: 3,030 Days
• Field of Search: 296/021, 296/04, 296/06, 298/27, 336/83, 336/200, 336/208, 336/82, 252/62.15 R, 252/62.6
• US Class Current: 29/602.1
• CPC Class Codes: H01F 17/04 with magnetic core
• CPC Class Codes: H01F 2027/2814 with only part of the coil or of the winding in the printed circuit board, e.g. the remaining coil or winding sections can be made of wires or sheets
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/37147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/40245 the item being metallic
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49096 horizontal
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 23/495 Lead-frames or other flat leads H01L23/498 takes precedence; lead frame interconnections between components H01L23/52
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 25/16 the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits
• 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 2924/00015 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed as prior art
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19105 : in a side-by-side arrangement on a common die mounting substrate
• CPC Class Codes: H02M 3/003 : Constructional details, e.g. physical layout, assembly, wiring or busbar connections
• CPC Class Codes: Y10T 29/4902 : Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49073 : by assembling coil and core
• CPC Class Codes: Y10T 29/49121 : Beam lead frame or beam lead device

Abstract

A method of forming a magnetic device by providing a conductive substrate and placing a magnetic core proximate the conductive substrate with a surface thereof facing the conductive substrate. The method also includes placing a conductive clip proximate a surface of the magnetic core and electrically coupling ends of the conductive clip to the conductive substrate to cooperatively form a winding therewith about the magnetic core.

Claims

1. A method of forming a magnetic device employable in a power module, comprising:

providing a conductive substrate employable in said power module;

placing a magnetic core proximate said conductive substrate with a lower surface adhered to an adhesive on said conductive substrate, said magnetic core having an overall end-to-end length and a continuous upper surface;

placing a planar surface of a conductive clip above said continuous upper surface of said magnetic core, said conductive clip continuously spanning said overall end-to-end length and said continuous upper surface of said magnetic core in a plane parallel to said conductive substrate; and

electrically coupling ends of said conductive clip to said conductive substrate to allow said conductive clip to form a portion of a winding about said magnetic core.

2. The method as recited in claim 1 wherein said conductive clip is about 8 to 12 mils in thickness.

3. The method as recited in claim 1 wherein said continuous upper surface of said magnetic core is substantially planar.

4. The method as recited in claim 1 wherein said magnetic core is formed from manganese zinc ferrite.

5. The method as recited in claim 1 wherein said conductive substrate is a leadframe.

6. The method as recited in claim 1 wherein said adhesive is a die attached adhesive.

7. The method as recited in claim 1 wherein said ends of said conductive clip are bent toward said conductive substrate about ends of said magnetic core.

8. The method as recited in claim 1 further comprising soldering said conductive clip to said conductive substrate.

9. The method as recited in claim 1 further comprising providing a gap between said conductive clip and said magnetic core.

10. The method as recited in claim 1 further comprising encapsulating said magnetic core, said conductive clip and said conductive substrate.

11. The method as recited in claim 1 wherein said continuous upper surface of said magnetic core is rectangular.

12. A method of forming a magnetic device employable in a power module, comprising:

providing a patterned, conductive leadframe employable in said power module;

adhering a magnetic core formed from a bar of magnetic material to an adhesive on said conductive leadframe, said magnetic core having an overall end-to-end length and a continuous upper surface;

placing a planar surface of at least one conductive clip above said continuous upper surface of said magnetic core, said at least one conductive clip continuously spanning said overall end-to-end length and said continuous upper surface of said magnetic core in a plane parallel to said conductive leadframe; and

soldering ends of said at least one conductive clip to said conductive leadframe to allow said conductive clip to form a portion of a winding about said magnetic core.

13. The method as recited in claim 12 wherein said bar of magnetic material is formed from manganese zinc ferrite.

14. The method as recited in claim 12 further comprising forming terminals for external electrical connections by creating leadframe fingers in said conductive leadframe.

15. The method as recited in claim 12 further comprising electrically coupling portions of said conductive leadframe with at least one wire bond.

16. The method as recited in claim 12 wherein said ends of said at least one conductive clip are bent toward said conductive leadframe about ends of said magnetic core.

17. The method as recited in claim 12 further comprising providing a gap between said magnetic core and said at least one conductive clip.

18. The method as recited in claim 12 further comprising providing a gap between said magnetic core and said at least one conductive clip and further comprising substantially filling said gap with an encapsulant.

19. The method as recited in claim 12 further comprising encapsulating said magnetic core, said at least one conductive clip and said conductive leadframe.

20. The method as recited in claim 12 further comprising encapsulating said magnetic core, said at least one conductive clip and said conductive leadframe with an epoxy encapsulant.

21. The method as recited in claim 12 wherein said magnetic device is an inductor.