Multi-Layer Inductive Element for Integrated Circuit

• US 20080252407A1
• Filed: 10/04/2006
• Published: 10/16/2008
• Est. Priority Date: 10/05/2005
• Status: Abandoned Application

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Anderson, Alma
• Application Number:
  US12/088,730
• Publication Number:
  US 20080252407A1
• Time in Patent Office: Days
• US Class Current: 336/177
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a magnetic core
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

According to one example embodiment, an inductive element is used for power-conversion applications. The inductive element includes a substrate (188) having a first metal layer (190) on the substrate having a thickness greater than one micrometer and arranged as a first set of adjacent non-intersecting conducting segments. There is a ferromagnetic-based body (192) located on the first metal layer that has a ferromagnetic inner core area. At least one other metal layer (198) is on the ferromagnetic-based body and arranged as a second set of adjacent non-intersecting conducting segments. A plurality of conductive vias (194) are located in the ferromagnetic-based body and are arranged to connect respective ones of the first set of adjacent non-intersecting conducting segments to respective ones of the second set of adjacent non-intersecting conducting segments therein providing a contiguous conductive wrap around the inner core area. Other example embodiments include layer thicknesses in excess of those used in normal semiconductor processing.

Claims

1. An inductive element comprising:

a substrate;

a first layer on the substrate having a thickness greater than one micrometer and arranged as a first set of adjacent non-intersecting conducting segments;

a ferromagnetic-based located on the first layer and having a ferromagnetic inner core area;

at least one other on the ferromagnetic-based body and arranged as a second set of adjacent non-intersecting conducting segments;

and a plurality of conductive vias in the ferromagnetic-based body arranged to connect respective ones of the first set of adjacent non-intersecting conducting segments to respective ones of the second set of adjacent non-intersecting conducting segments, therein providing a contiguous conductive wrap around the inner core area for use in power conversion.

2. The inductive element of claim 1, wherein the first layer includes metal and has a thickness of at least two micrometers.

3. The inductive element of claim 1, wherein the ferromagnetic inner core area is in the shape of a toroid.

4. The inductive element of claim 1, wherein the ferromagnetic inner core area is at least ten micrometers thick.

5. The inductive element of claim 1, wherein the ferromagnetic-based body includes an insulating layer covering the ferromagnetic inner core area.

6. The inductive element of claim 1, wherein the ferromagnetic core includes iron, magnesium, and oxygen.

7. The inductive element of claim 1, wherein each of the plurality of conductive vias has a diameter of at least 7 micrometers.

8. A method for forming an inductive element on an IC substrate, the method comprising:

forming a first layer on the substrate as a first set of adjacent non-intersecting conducting segments;

depositing a ferromagnetic-based body having a ferromagnetic inner core area on the first layer;

etching a plurality of vias through the ferromagnetic-based body to access the first layer;

filling the plurality of vias with conductive material to contact respective ones of the first set of adjacent non-intersecting conducting segments;

and forming at least one other layer on the ferromagnetic-based body as a second set of adjacent non-intersecting conducting segments, where the plurality of filled vias connect respective ones of the first set of adjacent non-intersecting conducting segments to respective ones of the second set of adjacent non-intersecting conducting segments to form a contiguous conductive wrap around the inner core area for use in power conversion.

9. The method of claim 8, wherein depositing a ferromagnetic-based body having a ferromagnetic inner core area includes depositing an insulating layer over the ferromagnetic inner core area.

10. The method of claim 8, wherein depositing a ferromagnetic-based body having a ferromagnetic inner core area includes silk screening an ink base on the first layer.

11. The method of claim 8, wherein depositing a ferromagnetic-based body having a ferromagnetic inner core area includes depositing an organic layer and a hard mask.

12. The method of claim 8, wherein forming at least one other layer on the ferromagnetic-based body includes using photoresist for patterning.

13. The method of claim 8, wherein forming at least one other layer on the ferromagnetic-based body includes using a blanket etch.

14. The method of claim 10, wherein depositing an ink base via silk screening includes forming a ferromagnetic inner core area that is at least 10 micrometers thick.