Semiconductor structure including guard ring

1. A semiconductor structure, comprising:

a conductive feature;

an outer guard ring; and

an inner guard ring between said outer guard ring and said conductive feature, said inner guard ring being at the same voltage as said conductive feature,

wherein said inner guard ring is part of a final metallization level; and

wherein said conductive feature is embedded in a dielectric layer, said dielectric layer including a contaminated portion between said outer guard ring and said conductive feature.

2. The structure of claim 1 , wherein said outer guard ring at least partially encircles said conductive feature.

3. The structure of claim 1 , wherein said inner guard ring at least partially encircles said conductive feature.

4. The structure of claim 1 , wherein said conductive feature is part of a final metallization level.

5. The structure of claim 1 , wherein said conductive feature is a conductive coil.

6. The structure of claim 1 , wherein said conductive feature is a transformer, said transformer including an upper coil over a lower coil.

7. The semiconductor structure of claim 1 , wherein said outer guard ring is proximate the periphery of said semiconductor structure.

8. The structure of claim 1 , wherein said inner guard ring is positioned so that there is substantially no lateral electric field through said contaminated portion.

9. The structure of claim 1 , wherein said inner guard ring is between said outer guard ring and said contaminated portion.

10. The structure of claim 1 , wherein a resistivity of said contaminated portion is less than a resistivity of a non-contaminated portion of said dielectric layer.

11. The structure of claim 1 , wherein said conductive feature is a capacitor.

12. The structure of claim 1 , wherein said conductive feature is a capacitor, said capacitor including an upper capacitor plate over a lower capacitor plate.

13. A semiconductor structure, comprising:

a conductive feature;

an outer guard ring; and

an inner guard ring between said outer guard ring and said conductive feature, said inner guard ring being electrically coupled to said conductive feature, wherein said inner guard ring is part of a final metallization level, and

wherein said conductive feature is embedded in a dielectric layer, said dielectric layer including a contaminated portion between said outer guard ring and said conductive feature.

14. The structure of claim 13 , wherein said outer guard ring at least partially encircles said conductive feature.

15. The structure of claim 13 , wherein said inner guard ring at least partially encircles said conductive feature.

16. The structure of claim 13 , wherein said conductive feature is part of a final metallization level.

17. The structure of claim 13 , wherein said conductive feature is a conductive coil.

18. The structure of claim 13 , wherein said conductive feature is a transformer, said transformer including an upper coil over a lower coil.

19. The semiconductor structure of claim 13 , wherein said outer guard ring is proximate the periphery of said semiconductor structure.

20. The structure of claim 13 , wherein said inner guard ring is positioned so that there is substantially no lateral electric field in said contaminated portion.

21. The structure of claim 13 , wherein said inner guard ring is positioned so that there is substantially no current in said contaminated portion.

22. The structure of claim 13 , wherein said inner guard ring is between said outer guard ring and said contaminated portion.

23. The structure of claim 13 , wherein a resistivity of said contaminated portion is less than a resistivity of a non-contaminated portion.

24. The structure of claim 13 , wherein said conductive feature is a capacitor.

25. The structure of claim 13 , wherein said conductive feature is a capacitor, said capacitor including an upper capacitor plate over a lower capacitor plate.

26. A semiconductor structure, comprising:

a dielectric layer, said dielectric layer having a contaminated portion;

a conductive feature disposed in said dielectric layer, said conductive feature being at a first voltage;

an outer guard ring disposed in said dielectric layer, said outer guard ring being at a second voltage different from said first voltage; and

an inner guard ring between said outer guard ring and said contaminated portion,

wherein there is substantially no lateral electric field within said contaminated portion.

27. The structure of claim 26 , wherein said outer guard ring at least partially encircles said conductive feature.

28. The structure of claim 26 , wherein said inner guard ring at least partially encircles said conductive feature.

29. The structure of claim 26 , wherein said conductive feature is part of a final metallization level.

30. The structure of claim 26 , wherein said conductive feature is a conductive coil.

31. The structure of claim 26 , wherein said conductive feature is a transformer, said transformer including an upper coil over a lower coil.

32. The structure of claim 26 , wherein said inner guard ring is part of a final metallization level.

33. The structure of claim 26 , wherein said contaminated portion has a resistivity less than a remaining portion of said dielectric layer.

34. A semiconductor structure, comprising:

a dielectric layer, said dielectric layer having a contaminated portion;

a conductive feature disposed in said dielectric layer, said conductive feature being at a first voltage;

an outer guard ring disposed in said dielectric layer, said outer guard ring being at a second voltage different from said first voltage; and

an inner guard ring between said outer guard ring and said contaminated portion,

wherein there is substantially no lateral electric field proximate said conductive feature.

35. The structure of claim 26 , wherein said conductive feature is a capacitor.

36. The structure of claim 26 , wherein said conductive feature is a capacitor, said capacitor including an upper capacitor plate over a lower capacitor plate.