Integrated circuit inductor with a magnetic core

• US 6,756,875 B2
• Filed: 02/03/2003
• Issued: 06/29/2004
• Est. Priority Date: 03/10/2000
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Ahn, Kie Y., Forbes, Leonard
• Primary Examiner(s): Mai, Anh
• Application Number:
  US10/357,528
• Publication Number:
  US 20030137385A1
• Time in Patent Office: 512 Days
• Field of Search: 336/200, 336/223, 336/232
• US Class Current: 336/200
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a magnetic core
• CPC Class Codes: H01F 17/045 with core of cylindric geometry and coil wound along its longitudinal axis, i.e. rod or drum core
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: H01F 5/003 Printed circuit coils
• CPC Class Codes: H01L 28/10 Inductors
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

An inductor is fabricated on a substrate having a top surface and a bottom surface. The inductor includes a plurality of holes extending through the substrate, wherein the plurality of holes interconnect the top surface and the bottom surface of the substrate. The inductor also includes a plurality of conductive posts formed in the plurality of holes and a plurality of conductive segments formed on the top surface and on the bottom surface that interconnect the conductive posts such that a continuous conductive coil is formed. The inductor also includes a magnetic core that occupies substantially the entire volume enclosed by the conductive coil.

Claims

1. An inductor comprising:

a substrate;

a magnetic core comprising a porous region of said substrate treated with a ferromagnetic material;

a conductive coil surrounding said magnetic core; and

a passivation layer covering said conductive coil.

2. The inductor of claim 1, wherein said substrate comprises a semiconductor.

3. The inductor of claim 1, wherein said substrate comprises silicon.

4. The inductor of claim 1, wherein said substrate comprises silicon carbide.

5. The inductor of claim 1, wherein said substrate comprises germanium.

6. The inductor of claim 1, wherein said substrate comprises a package for an electronic device.

7. The inductor of claim 4, wherein said substrate comprises a ceramic material.

8. The inductor of claim 1, wherein said porous region is formed using an anodic etching process.

9. The inductor of claim 1, wherein said porous region is formed using a laser ablation process.

10. The inductor of claim 1, wherein said treatment with a ferromagnetic material comprises a chemical vapor deposition process.

11. The inductor of claim 1, wherein said magnetic core comprises a magnetic oxide.

12. The inductor of claim 1, wherein said ferromagnetic material comprises Permalloy.

13. The inductor of claim 1, wherein said conductive coil comprises copper.

14. The inductor of claim 1, wherein said conductive coil comprises gold.

15. The inductor of claim 1, wherein said conductive coil comprises a plurality of conductive posts extending through said substrate and interconnected by a plurality of conductive straps.

16. The inductor of claim 15, wherein each of said plurality of conductive posts and said plurality of conductive straps is fabricated from a different conductive material.

17. The inductor of claim 15, wherein each of said plurality of conductive posts and said plurality of conductive straps is fabricated from one of two different metals.

18. The inductor of claim 17, wherein a first one of said metals comprises copper and a second one of said metals comprises aluminum.

19. The inductor of claim 15, wherein said conductive posts are configured in two substantially parallel rows.

20. The inductor of claim 15, wherein said substrate has at least two substantially parallel surfaces, and wherein said conductive posts are substantially perpendicular to said surfaces.

21. The inductor of claim 15, wherein said conductive posts have circular cross-sections.

22. The inductor of claim 15, wherein said conductive posts are at least partially surrounded by an insulating material.

23. The inductor of claim 22, wherein said insulating material comprises polyimide.

24. The inductor of claim 1, wherein said inductor has an inductance of at least 1 nanohenry.

25. The inductor of claim 1, wherein said passivation layer is configured to electrically insulate said inductor and to protect said inductor from physical damage.