Method for fabrication of high inductance inductors and related structure

• US 6,417,755 B1
• Filed: 08/25/2000
• Issued: 07/09/2002
• Est. Priority Date: 08/25/2000
• Status: Expired due to Term

• Current Assignee: Newport Fab, LLC (Tower Semiconductor Limited)
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Liu, Q. Z., Howard, David J
• Primary Examiner(s): MAI, ANH T
• Application Number:
  US09/649,442
• Time in Patent Office: 683 Days
• Field of Search: 296/021, 296/06, 296/07, 336/200, 336/223, 336/232, 336/83
• 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 17/04 with magnetic core
• CPC Class Codes: H01F 2017/0066 with a magnetic layer
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

According to various embodiments, a conductor is patterned in a dielectric. The conductor can be patterned, for example, in the shape of a square spiral. The conductor can comprise, for example, copper, aluminum, or copper-aluminum alloy. The dielectric can be, for example, silicon oxide or a low-k dielectric. Trenches are etched next to the patterned conductor in the dielectric. The trenches are filled with a material having a permeability substantially higher than the permeability of the dielectric. The high permeability material can be, for example, nickel, iron, nickel-iron alloy, or magnetic oxide. As a result, an inductor having a high inductance value is achieved without lowering the quality factor of the inductor.

Claims

1. A method comprising steps of:

patterning a conductor in a dielectric, said dielectric having a first permeability;

etching a trench in said dielectric, said trench being adjacent to said conductor;

filling said trench with a high permeability material, said high permeability material having a second permeability greater than said first permeability.

2. The method of claim 1 wherein said conductor is selected from the group consisting of copper, aluminum, and copper-aluminum alloy.

3. The method of claim 1 wherein said conductor is patterned as a square spiral.

4. The method of claim 1 wherein said dielectric is silicon dioxide.

5. The method of claim 1 wherein said dielectric is a low-k dielectric.

6. The method of claim 1 wherein said high permeability material is selected from the group consisting of nickel, iron, nickel-iron alloy, and magnetic oxide.

7. A structure comprising:

a conductor patterned in a dielectric, said dielectric having a first permeability;

a trench in said dielectric, said trench being adjacent to said conductor;

said trench being filled with a high permeability material, said high permeability material having a second permeability greater than said first permeability.

8. The structure of claim 7 wherein said conductor is selected from the group consisting of copper, aluminum, and copper-aluminum alloy.

9. The structure of claim 7 wherein said conductor is patterned as a square spiral.

10. The structure of claim 7 wherein said dielectric is silicon dioxide.

11. The structure of claim 7 wherein said dielectric is a low-k dielectric.

12. The structure of claim 7 wherein said high permeability material is selected from the group consisting of nickel, iron, nickel-iron alloy, and magnetic oxide.

13. An inductor in a semiconductor die, said inductor comprising:

a plurality of metal turns in a dielectric, said dielectric having a first permeability;

a plurality of trenches, each of said plurality of trenches being filled with a permeability conversion material;

said permeability conversion material having a second permeability greater than said first permeability, said permeability conversion material causing an increase in an inductance of said inductor.

14. The inductor of claim 13 wherein said plurality of metal turns comprise copper.

15. The inductor of claim 13 wherein said plurality of metal turns comprise aluminum.

16. The inductor of claim 13 wherein said plurality of metal turns comprise copper-aluminum alloy.

17. The inductor of claim 13 wherein said plurality of metal turns form a square spiral.

18. The inductor of claim 13 wherein said dielectric is silicon dioxide.

19. The inductor of claim 13 wherein said dielectric is a low-k dielectric.

20. The inductor of claim 13 wherein said permeability conversion material is selected from the group consisting of nickel, iron, nickel-iron alloy, and magnetic oxide.