Ground Shield Capacitor

• US 20110116208A1
• Filed: 11/10/2010
• Published: 05/19/2011
• Est. Priority Date: 11/17/2009
• Status: Active Grant

• Current Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Signoff, David M., Loeb, Wayne A.
• Granted Patent: US 8,988,852 B2
• Time in Patent Office: Days
• US Class Current: 361/301.1
• CPC Class Codes: H01G 4/002 Details
• CPC Class Codes: H01G 4/228 Terminals

Abstract

In one embodiment, an apparatus includes a first reference voltage coupled to a first metal layer and a second reference voltage coupled to a second metal layer. A first finger type in the plurality of fingers is coupled to the first metal layer at a first area and coupled to the first metal layer and the second metal layer at a second area. A second finger type in the plurality of fingers is coupled to the second metal layer at the first area and coupled to the first metal layer and the second metal layer at the second area. Also, the first finger type and the second finger type alternately positioned next to each other.

Claims

1. An apparatus comprising:

a first reference voltage coupled to a first metal layer;

a second reference voltage coupled to a second metal layer; and

a plurality of fingers, wherein;

a first finger type in the plurality of fingers is coupled to the first metal layer at a first area and coupled to the first metal layer and the second metal layer at a second area, and

a second finger type in the plurality of fingers is coupled to the second metal layer at the first area and coupled to the first metal layer and the second metal layer at the second area, and

the first finger type and the second finger type alternately positioned next to each other.

2. The apparatus of claim 1, wherein:

the first finger type is further coupled to a third metal layer at the first area and coupled to the third metal layer and a fourth metal layer at the second area, and

the second finger type is further coupled to the fourth metal layer at the first area and coupled to the third metal layer and the fourth metal layer at the second area.

3. The apparatus of claim 2, wherein:

the first finger type is coupled to the first metal layer and the third metal layer at the first area and coupled to the first metal layer, the second metal layer, the third metal layer and the fourth metal layer at the second area, and

the second finger type is coupled to the second metal layer and the fourth metal layer at the first area and coupled to the first metal layer, the second metal layer, the third metal layer and the fourth metal layer at the second area.

4. The apparatus of claim 1, wherein the first reference voltage comprises ground and the second reference voltage comprises a voltage supply.

5. The apparatus of claim 1, wherein:

the plurality of fingers comprise a third finger type,

the first finger type is coupled to the third finger type at the first metal layer at the first area, and

the second finger type is coupled to the third finger type at the second metal layer at the first area.

6. The apparatus of claim 5, wherein the third finger type is coupled to the first metal layer and the second metal layer.

7. The apparatus of claim 1, wherein a capacitance forms horizontally between the first finger type and the second finger type.

8. The apparatus of claim 1, further comprising a break in a capacitance between two of the plurality of fingers.

9. The apparatus of claim 1, wherein the plurality of fingers form an alternating current (AC) coupling ground shield capacitor.

10. The apparatus of claim 1, wherein the plurality of fingers form a first alternating current (AC) coupling ground shield capacitor and a second AC coupling ground shield capacitor.

11. The apparatus of claim 1, wherein the plurality of fingers form a tuning alternating current (AC) coupling ground shield capacitor.

12. A system comprising the apparatus of claim 1, the system further comprising:

a passive device, wherein the apparatus is included under the passive device.

13. The system of claim 12, wherein the passive device comprises an inductor or a transformer.

14. A method comprising:

coupling a first reference voltage to a first finger type in a plurality of fingers on a first metal layer at a first area;

coupling the first reference voltage to the first metal layer and a second metal layer at a second area;

coupling a second reference voltage to a second finger type in the plurality of fingers on the second metal layer at the first area; and

coupling the second reference voltage to the first metal layer and the second metal layer at the second area,

wherein the first finger type and the second finger type are alternately positioned next to each other.

15. The method of claim 14, further comprising:

coupling the first reference voltage to the first finger type in the plurality of fingers on a third metal layer at the first area; and

coupling the second reference voltage to the second finger type in the plurality of fingers on a fourth metal layer at the first area.

16. The method of claim 15, further comprising:

coupling the first reference voltage to the first finger type in the plurality of fingers on the first metal layer, the second metal layer, the third metal layer, and the fourth metal layer at the second area; and

coupling the second reference voltage to the second finger type in the plurality of fingers on the first metal layer, the second metal layer, the third metal layer, and the fourth metal layer at the second area.

17. The method of claim 14, wherein the first reference voltage comprises ground and the second reference voltage comprises a voltage supply.

18. The method of claim 14, further comprising providing a break in a capacitance between two of the plurality of fingers.

19. The method of claim 14, further comprising:

coupling the first reference voltage through a third finger type on the first metal layer; and

coupling the second reference voltage through the third finger type on the second metal layer,

wherein the first finger type is coupled to the first metal layer at the third finger type and the second finger type is coupled to the second metal layer at the third finger type.

20. The method of claim 19, further comprising:

further coupling the first reference voltage through the third finger type on a third metal layer; and

further coupling the second reference voltage through the third finger type on a fourth metal layer,

wherein the first finger type is coupled to the first metal layer and the third metal layer at the third finger type and the second finger type is coupled to the second metal layer and the fourth metal layer at the third finger type.