System and method for manufacturing an out of plane integrated circuit inductor

• US 7,229,908 B1
• Filed: 06/04/2004
• Issued: 06/12/2007
• Est. Priority Date: 06/04/2004
• Status: Active Grant

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Drizlikh, Sergei, Thibeault, Todd
• Primary Examiner(s): Geyer; Scott B.
• Application Number:
  US10/861,563
• Time in Patent Office: 1,103 Days
• Field of Search: None
• US Class Current: 438/622
• CPC Class Codes: H01L 28/10 Inductors

Abstract

A system and method is described for manufacturing an out of plane integrated circuit inductor. A plurality of parallel metal bars are formed on a substrate and covered with a first passivation layer. A ferromagnetic core is then deposited over the first passivation layer with its length perpendicular to the plurality of parallel metal bars. A second passivation layer is deposited over the ferromagnetic core and vias are etched through the passivation layers to the alternate ends of the underlying parallel metal bars. A plurality of cross connection metal bars are then formed on the second passivation layer with vertical portions that fill the vias and connect the alternate ends of the plurality of parallel metal bars to form an inductor coil. A third passivation layer is then deposited over the cross connection metal bars.

Claims

1. A method for manufacturing an out of plane integrated circuit inductor, said method comprising the steps of:

providing a substrate;

creating a plurality of metal bars on said substrate;

depositing a first passivation layer over said plurality of metal bars and over said substrate;

etching vias through said first passivation layer to alternate ends of the plurality of metal bars; and

creating on said first passivation layer a plurality of cross connection metal bars having vertical portions that fill said vias and that connect said alternate ends of said plurality of metal bars to form said integrated circuit inductor;

wherein the first passivation layer is self-planarizing and has a thickness that is approximately one-half of a thickness of one or more coils formed by the metal bars, the vias and the cross connection metal bars.

2. The method as set forth in claim 1 further comprising the step of:

depositing a second passivation layer over said plurality of cross connection metal bars and over said first passivation layer.

3. The method as set forth in claim 1 wherein each of said plurality of metal bars is parallel with respect to each other of said plurality of metal bars.

4. The method as set forth in claim 1 wherein each of said plurality of cross connection metal bars is parallel with respect to each other of said plurality of cross connection metal bars.

5. The method as set forth in claim 1 wherein said plurality of metal bars are made of at least one of:

copper and aluminum.

13. The method as set forth in claim 1, wherein the first passivation layer comprises benzo-cyclobutene (BCB).

6. An out of plane integrated circuit inductor comprising:

a plurality of metal bars on a substrate;

a first passivation layer deposited over said plurality of metal bars and over said substrate;

a plurality of vias etched through said first passivation layer to alternate ends of the plurality of metal bars; and

a plurality of cross connection metal bars on said first passivation layer, said plurality of cross connection metal bars having vertical portions that fill said vias and that connect said alternate ends of said plurality of metal bars to form said integrated circuit inductor;

wherein the first passivation layer is self-planarizing and has a thickness that is approximately one-half of a thickness of one or more coils formed by the metal bars, the vias, and the cross connection metal bars.

7. The out of plane integrated circuit inductor as set forth in claim 6 further comprising a second passivation layer over said plurality of cross connection metal bars and over said first passivation layer.

8. The out of plane integrated circuit inductor as set forth in claim 6 wherein each of said plurality of metal bars is parallel with respect to each other of said plurality of metal bars.

9. The out of plane integrated circuit inductor as set forth in claim 7 wherein each of said plurality of cross connection metal bars is parallel with respect to each other of said plurality of cross connection metal bars.

10. The out of plane integrated circuit inductor as set forth in claim 7 wherein said plurality of metal bars are made of at least one of:

copper and aluminum.

11. The out of plane integrated circuit inductor as set forth in claim 7 wherein said substrate comprises a portion of an integrated circuit that contains circuit elements.

12. The out of plane integrated circuit inductor as set forth in claim 7, wherein the first passivation layer comprises benzo-cyclobutene (BCB).

14. An integrated circuit, comprising:

a substrate; and

a plurality of circuit elements formed on the substrate, the circuit elements including an out of plane inductor that comprises;

a first plurality of metal bars;

a first passivation layer deposited over the first plurality of metal bars;

a plurality of vias etched through the first passivation layer to alternate ends of the first plurality of metal bars; and

a second plurality of metal bars on the first passivation layer, the second plurality of metal bars having portions that fill the vias and connecting the alternate ends of the first plurality of metal bars;

wherein the first passivation layer is self-planarizing and has a thickness that is approximately one-half of a thickness of one or more coils formed by the first plurality of metal bars, the vias, and the second plurality of metal bars.

15. The integrated circuit as set forth in claim 14, wherein the out of plane inductor further comprises:

a second passivation layer over the second plurality of metal bars and the first passivation layer.

16. The integrated circuit as set forth in claim 14, wherein the first plurality of metal bars are parallel with respect to each other.

17. The integrated circuit as set forth in claim 14, wherein the second plurality of metal bars are parallel with respect to each other.

18. The integrated circuit as set forth in claim 14, wherein the first and second plurality of metal bars are made of at least one of:

copper and aluminum.

19. The integrated circuit as set forth in claim 14, wherein the first passivation layer comprises benzo-cyclobutene (BCB).

20. The integrated circuit as set forth in claim 14, wherein the out of plane inductor further comprises:

a plurality of second vias etched through the first passivation layer to ends of two of the first plurality of metal bars; and

metal contacts formed in the second vias for coupling the out of plane inductor to at least one other circuit element.