Integrated circuit inductor with a magnetic core

• US 6,531,945 B1
• Filed: 03/10/2000
• Issued: 03/11/2003
• Est. Priority Date: 03/10/2000
• Status: Expired due to Fees

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Ahn, Kie Y., Forbes, Leonard
• Primary Examiner(s): Mai, Anh T.
• Application Number:
  US09/523,097
• Time in Patent Office: 1,096 Days
• Field of Search: 336/200, 336/223, 336/232, 292/06, 292/021
• 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 embedded within said substrate; and

a three-dimensional conductive coil comprising a plurality of conductive posts interconnected by a plurality of conductive segments,

wherein said conductive coil surrounds said magnetic core, and

wherein said magnetic core comprises a porous region of said substrate having a ferromagnetic material deposited therein.

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

3. The inductor of claim 1, wherein each of said plurality of conductive posts and said plurality of conductive segments is fabricated from a different conductive material.

4. The inductor of claim 1, wherein each of said plurality of conductive posts and said plurality of conductive segments is fabricated from one of two different metals.

5. A method of fabricating an inductor embedded in a substrate, said method comprising the steps of:

forming a plurality of paths extending through said substrate;

forming a magnetic core in said substrate;

depositing a conductive material in said paths to form a plurality of conductive posts; and

fabricating a plurality of conductive segments that interconnect said conductive posts to form a conductive coil,

wherein said step of forming a magnetic core comprises;

forming a porous region in said substrate; and

depositing a ferromagnetic material in said porous region.

6. The method of claim 5, wherein said step of forming a plurality of paths comprises forming two substantially parallel rows of paths extending through said substrate.

7. The method of claim 5, wherein said step of forming a plurality of paths comprises using an etching process.

8. The method of claim 5, wherein said step of forming a plurality of paths comprises using a laser.

9. The method of claim 5, wherein said step of forming a plurality of paths comprises using a drill.

10. The method of claim 5, wherein said step of forming a magnetic core comprises forming a magnetic core in a region of said substrate bounded by said plurality of paths.

11. The method of claim 5, wherein said step of forming a porous region comprises using an anodic etching process.

12. The method of claim 5, wherein said step of forming a porous region comprises using a laser ablation process.

13. The method of claim 5, wherein said step of depositing a ferromagnetic material comprises depositing Permalloy.

14. The method of claim 5, wherein said step of depositing a ferromagnetic material comprises using a chemical vapor deposition process.

15. The method of claim 5, wherein said step of depositing a conductive material in said paths comprises one of filling or lining said paths with said conductive material.