Saucer-shaped half-loop MEMS inductor with very low resistance

• US 7,250,841 B1
• Filed: 08/25/2005
• Issued: 07/31/2007
• Est. Priority Date: 08/25/2005
• Status: Active Grant

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Johnson, Peter, Hopper, Peter J., Hwang, Kyuwoon, Lindorfer, Philipp
• Primary Examiner(s): MAI, ANH T
• Application Number:
  US11/213,155
• Time in Patent Office: 705 Days
• Field of Search: 336/200, 336/223, 336/232, 336/82, 336173-175
• US Class Current: 336/82
• 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: 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: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49069 Data storage inductor or core
• CPC Class Codes: Y10T 29/49165 by forming conductive walled aperture in base

Abstract

A micro-electromechanical system (MEMS) inductor is formed in a saucer shape that completely surrounds a magnetic core structure which is formed from a ferromagnetic material. In addition, an array of MEMS inductors can be formed by dividing up the saucer-shaped MEMS inductor into a number of electrically-isolated MEMS inductor wedges.

Claims

1. An inductive semiconductor structure comprising:

a first via;

a second via;

a first conductive plate having a first region that contacts the first via, and a second region spaced-apart from the first via;

a second conductive plate that lies over the first conductive plate, the second conductive plate having a first region that contacts the second via, and a second region spaced-apart from the second via;

a conductive sidewall that has a bottom surface and a top surface, the bottom surface contacting the second region of the first conductive plate, and being spaced apart from the first region of the first conductive plate, the top surface contacting the second region of the second conductive plate, and being spaced apart from the first region of the second conductive plate; and

a magnetic core structure located between the first conductive plate and the second conductive plate, the magnetic core structure being electrically isolated from all other conductive regions.

2. The structure of claim 1 wherein the first regions of the first and second conductive plates are center regions, and the second regions are peripheral regions that surround the center regions.

3. The structure of claim 2 wherein the conductive sidewall completely encircles the magnetic core structure.

4. The structure of claim 3 wherein the second via is located directly over the first via.

5. The structure of claim 3 wherein a current flows between the first and second vias when a potential difference exists between the first and second vias.

6. The structure of claim 5 wherein a plurality of magnetic flux lines follow a circular path around the center region entirely within the magnetic core structure when the current flows.

7. The structure of claim 2 wherein the magnetic core structure includes concentric rings of a ferromagnetic material.

8. The structure of claim 1 and further comprising:

a third via;

a fourth via;

a third conductive plate having a first region that contacts the third via, and a second region spaced-apart from the third via, the first and third conductive plates lying in a common plane, the third conductive plate being electrically isolated from the first conductive plate;

a fourth conductive plate that lies over the third conductive plate, the fourth conductive plate having a first region that contacts the fourth via, and a second region spaced-apart from the fourth via, the second and fourth conductive plates lying a common plane, the fourth conductive plate being electrically isolated from the second conductive plate, the magnetic core structure lying between the third and fourth conductive plates; and

a conductive sidewall that has a bottom surface that contacts the second region of the third conductive plate, and a top surface that contacts the second region of the fourth conductive plate.

9. The structure of claim 8 wherein the magnetic core structure includes concentric rings of a ferromagnetic material.

10. The structure of claim 8 wherein a plurality of magnetic flux lines follow a circular path entirely within the magnetic core structure when a current flows between the first and second vias.

11. The structure of claim 8 and further comprising:

a fifth via;

a sixth via;

a fifth conductive plate having a first region that contacts the fifth via, and a second region spaced-apart from the fifth via, the first, third, and fifth conductive plates lying in the first common plane, the fifth conductive plate being electrically isolated from the first and third conductive plates;

a sixth conductive plate that lies over the fifth conductive plate, the sixth conductive plate having a first region that contacts the sixth via, and a second region spaced-apart from the sixth via, the second, fourth, and sixth conductive plates lying the second common plane, the sixth conductive plate being electrically isolated from the second and fourth conductive plates, the magnetic core structure being located between the fifth conductive plate and the sixth conductive plate; and

a conductive sidewall that has a bottom surface that contacts the second region of the fifth conductive plate, and a top surface that contacts the second region of the sixth conductive plate.

12. The structure of claim 11 wherein the magnetic core structure includes concentric rings of a ferromagnetic material.

13. The structure of claim 11 wherein a plurality of magnetic flux lines follow a circular path entirely within the magnetic core structure when a current flows between the first and second vias.