Shielding for through-silicon-via

1. An integrated circuit device, comprising:

a semiconductor body;

an active area of the semiconductor body;

a via penetrating through the semiconductor body without passing through the active area;

a first contiguous region throughout which the semiconductor body is p-doped to at least a first concentration, the first contiguous region surrounding an area of the semiconductor body comprising the active area; and

a second contiguous region throughout which the semiconductor body is p-doped to at least the first concentration, the second contiguous region surrounding the via, the second region being disjoint from the first contiguous region;

wherein the second contiguous region fully surrounds the first contiguous region, the semiconductor body is not p-doped or is p-doped to a second concentration that is less than the first concentration, and the via is outside the area surrounded by the first contiguous region.

2. The integrated circuit device of claim 1 , wherein the first contiguous region is at least 0.10 μm wide all around the active area.

3. The integrated circuit device of claim 1 , wherein the second contiguous region is at least 0.25 μm wide where the second contiguous region lies between the via and the active area.

4. The integrated circuit device of claim 1 , wherein:

the via and the active area are no more than 35 μm apart.

5. The integrated circuit device of claim 1 , wherein the active area is at least 100 μm 2 .

6. The integrated circuit device of claim 1 , wherein the first and second contiguous regions are electrically coupled to ground pads.

7. The integrated circuit device of claim 6 , wherein the first and second contiguous regions are electrically coupled to a same ground pad.

8. The integrated circuit device of claim 6 , wherein the first and second contiguous regions are electrically coupled to distinct ground pads.

9. The integrated circuit device of claim 1 , wherein the active area is formed within an n-well.

10. A 3D integrated circuit device, comprising:

first and second semiconductor bodies;

an active area of the first semiconductor body;

a via penetrating through the first semiconductor body, the via being outside the active area and forming a connection with a circuit formed in the second semiconductor body;

a first contiguous region throughout which the first semiconductor body is doped p+, the first contiguous region surrounding an area of the semiconductor body, the surrounded area comprising the active area but not the via; and

a second contiguous region throughout which the first semiconductor body is doped p+, the second region surrounding the via, the second region being disjoint from the first region;

wherein the second contiguous region encircles the first contiguous region, the semiconductor body is not p-doped or is p-doped to a concentration less than the first and second contiguous regions, and the via is outside the area surrounded by the first contiguous region.

11. The integrated circuit device of claim 10 wherein:

the second contiguous region has a width that varies with position about the via; and

the width of the second contiguous region is at its largest at a location within a space separating the via and the active area.

12. A method of shielding to prevent signals carried by a through-silicon-via from causing noise in an active area of an integrated circuit, comprising:

forming a first p+ guard ring around the through-silicon-via;

forming a second p+ guard ring around the active area; and

grounding the first and second p+ guard rings;

wherein the through silicon via is outside of the area fully surrounded by the first p+ guard ring.

13. The method of claim 12 , wherein:

the first p+ guard ring operates as a first ground having a first noise characteristic; and

the second p+ guard ring operates as a second ground having a second noise characteristic, wherein the first noise characteristic is different from the second noise characteristic.

14. The method of claim 12 , wherein the first and second p+ guard rings reduce a noise coupling coefficient between the through-silicon-via and the active area at 3 GHz circuit operating frequency to −60 dB or less.

15. The method of claim 12 , wherein the second p+ guard ring comprises a width of at least 0.25 μm between the through-silicon-via and the active area.

16. The method of claim 12 , wherein the second p+ guard ring encircles the first p+ guard ring.

17. The method of claim 12 , wherein:

the through-silicon-via and the active area are no more than 50 μm apart; and

the first and second p+ guard rings reduce the noise coupling coefficient at 3 GHz between the through-silicon-via and the active area to −60 dB or less.

18. The method of claim 12 , wherein the active area is at least 100 μm 2 .

19. An integrated circuit device, comprising:

a semiconductor body;

a through silicon via penetrating through the semiconductor body;

a first guard ring surrounding the through silicon via and being doped to a first concentration, which is less than a second concentration of the semiconductor body;

an active area disposed within the semiconductor body and being spaced and apart from both the first guard ring and the through silicon via; and

a second guard ring surrounding the active area and being disjoint from the first guard ring, the second guard ring being doped to the first concentration;

wherein the first guard ring fully surrounds the second guard ring.

20. The integrated circuit device of claim 19 , wherein the first and second guard rings surround mutually exclusive areas of the semiconductor body.

21. The integrated circuit device of claim 19 , wherein the first guard ring includes an extension that divides a total area encompassed by the first guard ring into first and second mutually exclusive sub-areas, wherein the first sub-area surrounds the through silicon via and wherein the second sub-area surrounds both the second guard ring and the active area.

22. The integrated circuit device of claim 21 , wherein the first sub-area is smaller than the second sub-area.