MEMS inductor with very low resistance

• US 7,250,842 B1
• Filed: 08/09/2005
• Issued: 07/31/2007
• Est. Priority Date: 08/09/2005
• 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, Drury, Robert
• Primary Examiner(s): Nguyen; Tuyen T.
• Application Number:
  US11/200,384
• Time in Patent Office: 721 Days
• Field of Search: 336/65, 336/83, 336/200, 336232-234, 336174-175, 257/531
• US Class Current: 336/200
• CPC Class Codes: H01F 10/14 containing iron or nickel H01F10/126 , H01F10/13, H01F10/16 take precedence
• CPC Class Codes: H01F 10/265 Magnetic multilayers non exchange-coupled H01F10/32 takes precedence
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a 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: H01F 41/309 electroless or electrodeposition processes from plating solution

Abstract

A very, very low resistance micro-electromechanical system (MEMS) inductor, which provides resistance in the single-digit milliohm range, is formed by utilizing a single thick wide loop of metal formed around a magnetic core structure. The magnetic core structure, in turn, can utilize a laminated Ni—Fe structure that has an easy axis and a hard axis.

Claims

1. A semiconductor inductor comprising:

a first conductive plate having a length, a width, and a thickness;

a second conductive plate that lies over the first conductive plate, the second conductive plate having a length, a width, and a thickness;

a conductive sidewall that has a bottom surface that contacts the first conductive plate, and a top surface that contacts the second conductive plate, the first conductive plate and the second conductive plate defining an enclosed region that lies only between the first and second conductive plates; and

a magnetic core structure located within the enclosed region, and within no other enclosed regions, the magnetic core structure being electrically isolated from all other conductive regions.

2. The semiconductor inductor of claim 1 wherein the conductive sidewall has a height measured between the first and second conductive plates, a length substantially equal to the width of the first conductive plate, and a width.

3. The semiconductor inductor of claim 1 wherein the core structure includes a plurality of plates.

4. The semiconductor inductor of claim 3 wherein the plurality of plates include laminated Ni—

Fe plates.

5. The semiconductor inductor of claim 4 wherein a laminated plate has a width substantially equal with the width of the first conductive plate.

6. The semiconductor inductor of claim 1 wherein the magnetic core structure has an easy axis aligned with the length of the first conductive plate.

7. The semiconductor inductor of claim 1 wherein the magnetic core structure has a hard axis aligned with the length of the first conductive plate.

8. A semiconductor inductor comprising:

a first conductive plate lying in a first plane, the first conductive plate including all contiguous conductive areas that lie in the first plane, and having a first edge and a spaced-apart second edge, a region of the first conductive plate extending continuously from the first edge to the second edge;

a second conductive plate lying in a second plane, the second conductive plate including all contiguous conductive areas that lie in the second plane, all of the region of the first conductive plate that extends continuously from the first edge to the second edge lying directly below the second conductive plate; and

a conductive sidewall having a bottom surface that contacts the first conductive plate, and a top surface that contacts the second conductive plate, the conductive sidewall being spaced apart from the first edge and contacting the first conductive plate adjacent to the second edge.

9. The semiconductor inductor of claim 8 and further comprising:

a region of non-conductive material contacting the bottom surface of the first conductive plate; and

a via extending through the region of non-conductive material, the via contacting the first conductive plate adjacent to the first edge and being spaced apart from the second edge.

10. The semiconductor inductor of claim 9 wherein the second conductive plate lies directly over the via.

11. The semiconductor inductor of claim 10 wherein an enclosed region lies only between the first and second conductive plates.

12. The semiconductor inductor of claim 11 and further comprising a magnetic core structure located only within the enclosed region, the magnetic core structure being electrically isolated from all other conductive regions.

13. The semiconductor inductor of claim 8 and further comprising a conductive section having a top surface and a bottom surface, the top surface of the conductive section contacting the second conductive plate, the conductive section being spaced apart from the first conductive plate, a portion of the conductive section lying in the first plane.

14. The semiconductor inductor of claim 13 and further comprising:

a region of non-conductive material contacting the bottom surface of the first conductive plate;

a first via extending through the region of non-conductive material, the first via contacting the first conductive plate adjacent to the first edge and spaced apart from the second edge; and

a second via extending through the region of non-conductive material, the second via contacting the bottom surface of the conductive section.

15. The semiconductor inductor of claim 14 wherein the second conductive plate lies directly over the first via and the second via.

16. The semiconductor inductor of claim 15 wherein an enclosed region lies only between the first and second conductive plates, and between the conductive sidewall and the conductive section.

17. The semiconductor inductor of claim 16 and further comprising a magnetic core structure located only within the enclosed region, the magnetic core structure being electrically isolated from all other conductive regions.