Raised on-chip inductor and method of manufacturing same

• US 20030001712A1
• Filed: 05/23/2002
• Published: 01/02/2003
• Est. Priority Date: 05/23/2001
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Liu, Chang, Zou, Jun, Schutt-Aine, Jose
• Granted Patent: US 6,922,127 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 41/041 Printed circuit coils apparatus or processes for manufacturing printed circuits in general H05K3/00
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• CPC Class Codes: H01L 27/08 including only semiconductor components of a single kind
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/19104 on the semiconductor or solid-state device, i.e. passive-on-chip
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49071 by winding or coiling

Abstract

A raised on-chip planar inductor. An inductor is fabricated on a substrate. The inductor, except for an anchoring extremity, is lifted from the substrate, preferably by application of a magnetic field to a magnetic layer formed on the inductor. The lifting of the inductor deforms a plastic bending region. After the magnetic field is removed, the inductor remains raised with respect to the substrate.

Claims

1. An integrated inductor disposed on a substrate, the inductor comprising:

a first conductor including an anchoring extremity that mechanically anchors said first conductor to the substrate, the first conductor being otherwise raised with respect to the substrate.

2. The inductor according to claim 1 wherein said first conductor, except for said anchoring extremity, is detached from the substrate.

3. The inductor according to claim 1 wherein the inductor is a planar spiral inductor.

4. The integrated circuit according to claim 3 wherein said first conductor is connected to said anchoring extremity via a plastic bending region near said anchoring extremity.

5. The integrated circuit according to claim 2 wherein said planar inductor further comprises:

a second conductor electrically connected to said first conductor, said second conductor including a part of said anchoring extremity and having a plastic bending region near said anchoring extremity.

6. The integrated circuit according to claim 5 wherein said planar inductor further comprises:

a dielectric bridge disposed between said first conductor and said second conductor.

7. The integrated circuit according to claim 2 wherein said first conductor is comprised of a ductile metal.

8. A method of forming an inductor on a substrate, comprising the steps of:

fabricating a planar inductor on the substrate, said planar inductor being anchored to the substrate by an anchoring extremity but otherwise detached from said substrate; and

lifting said planar inductor, except for said anchoring extremity, to plastically deform said planar inductor and lift said planar inductor, anchored by said anchoring extremity, into a raised position with respect to the substrate.

9. The method of claim 8 wherein said step of lifting said second end comprises the step of:

applying a magnetic field to said planar inductor to lift said planar inductor from said substrate.

10. The method of claim 9 wherein said applying step is maintained at least until part of said planar inductor is plastically deformed.

11. The method of claim 9 wherein said step of fabricating said planar inductor further comprises the step of:

forming a layer of magnetic material on a surface of said planar inductor.

12. The method of claim 11 wherein said magnetic material is not formed on a plastic bending region of said planar inductor disposed near said anchoring extremity.

13. The method of claim 12 wherein said plastic bending region comprises a ductile metal.

14. The method of claim 8 wherein said fabricating step further comprises the steps of:

forming a sacrificial layer on said substrate; and

forming said planar inductor on said sacrificial layer, except for said anchoring extremity.

15. The method of claim 14 further comprising the step of:

removing said sacrificial layer to release said inductor, except said anchoring extremity, from said substrate.

16. The method of claim 11 wherein said magnetic material is at least eight times thicker than a thickness of said inductor.

17. The method of claim 11 wherein said step of applying said magnetic field comprises the step of applying a magnetic field, said magnetic field containing a vector component that lies in a direction perpendicular to said surface of said substrate.

18. The method of claim 17 further comprising the steps of:

moving a direction of said magnetic field to rotate said inductor to an angle greater than 90 degrees with respect to said substrate; and

removing said magnetic field so that said inductor reverts to an angle of substantially 90 degrees with respect to said substrate.

19. The method of claim 8 wherein said step of fabricating comprises the step of:

forming a first conductor and a second conductor on said substrate.

20. The method of claim 19 further comprising the step of:

forming a dielectric bridge disposed between said first conductor and said second conductor.

21. The method of claim 9 wherein said step of applying said magnetic field further comprises the step of:

increasing said electric current as said inductor lifts with respect to said substrate.

22. The method of claim 12 further comprising the step of:

producing plastic deformation in said plastic bending region while lifting said inductor.

24. The integrated circuit of claim 23 wherein said step of lifting said second end comprises the step of:

applying a magnetic field to said planar inductor to lift said distal end of said planar inductor.

25. The integrated circuit of claim 24 wherein the inductor is formed by the further step of:

forming a magnetic layer on said surface of said planar inductor.

23. An integrated circuit having an inductor formed by the steps of:

fabricating a planar inductor on a substrate including a conductor extending between an anchoring extremity and a distal end; and

lifting said distal end while said anchoring extremity remains connected to said substrate to plastically deform said planar inductor and lift said inductor, except for said anchoring extremity, into a raised position with respect to said substrate.