INTEGRATED CIRCUIT COMB CAPACITOR

Abstract

The invention is directed to an integrated circuit comb capacitor with capacitor electrodes that have an increased capacitance between neighboring capacitor electrodes as compared with other interconnects and via contacts formed in the same metal wiring level and at the same pitches. The invention achieves a capacitor that minimizes capacitance tolerance and preserves symmetry in parasitic electrode-substrate capacitive coupling, without adversely affecting other interconnects and via contacts formed in the same wiring level, through the use of, at most, one additional noncritical, photomask.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The features and the element characteristics of the invention are set forth with particularity in the appended claims. The figures are for illustrative purposes only and are not drawn to scale. Furthermore, like numbers represent like features in the drawings. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows, taken in conjunction with the accompanying figures, in which:

FIG. 1 depicts a prior art integrated circuit comb capacitor 150.

FIGS. 2 a-2e depict the formation of an integrated circuit comb capacitor 250 in accordance with a first embodiment of the invention.

FIG. 3 depicts a VPP capacitor in accordance with the first embodiment of the invention.

FIG. 4 depicts a modified version of the VPP capacitor in FIG. 3.

FIGS. 5 a-5e depict the formation of an integrated circuit comb capacitor 550 in accordance with a second embodiment of the invention.

FIGS. 6 a-6e depict the formation of an integrated circuit comb capacitor 550 in accordance with a third embodiment of the invention.

Claims

1. A method for creating a capacitor, comprising the steps of: forming at least one capacitor opening and at least one non-capacitor opening in dielectric, said capacitor and non-capacitor opening formed in the same metal wiring level; and,modifying said dielectric along surfaces of said at least one capacitor opening such that said modification increases capacitance of said capacitor.

2. A method as in claim 1, said modifying step comprising: creating a modified dielectric along said surfaces of said at least one capacitor opening, by at least one of depleting carbon from said surfaces of said at least one capacitor opening.

3. A method as in claim 2, said modifying step further comprising, the step of: expanding said at least one capacitor opening by selectively: modifying said modified dielectric along said surfaces of said at least one capacitor opening;removing said modified dielectric along said surfaces of said at least one capacitor opening; and,filling said capacitor opening with a conductive material.

4. A method as in claim 1, said dielectric is porous, said at least one capacitor opening and said at least one non-capacitor opening are formed in said modified dielectric, and said modifying step comprises, the step of: infusing said modified dielectric along said surfaces of said capacitor opening with a material having a dielectric constant higher than said dielectric constant of said modified dielectric prior to modification.

5. A method as in claim 2, said modifying step further comprising, the step of: infusing said modified dielectric along said surfaces of said capacitor opening with a material having a dielectric constant higher than said dielectric constant of said modified dielectric prior to modification.

6. A method as in claim 1, said dielectric one of SiCOH and porous SiCOH.

7. A method as in claim 2, said depleting step comprising activating an oxidizing plasma, said activating plasma one of O2, N2O, and H2O.

8. A method as in claim 2, said depleting step comprising activating a reducing plasma, said reducing plasma one of N2/H2 and H2.

9. A method as in claim 2, said dielectric having a dielectric constant less than or approximately equal to 3.0, said modified dielectric with a dielectric constant greater than 4.0.

10. A method as in claim 3, said modified dielectric removed along said surfaces of said at least one capacitor opening with a diluted hydrofluoric acid.

11. A method as in claim 3, said conductive material comprises copper.

12. A method as in claim 4, said modified dielectric infused by one of one of PVD, CVD, IPVD, and ALD.

13. A method as in claim 5, said modified dielectric infused by one of one of PVD, CVD, IPVD, and ALD.

14. A method as in claim 5, said material comprises one of a metallic material and an insulating material.

15. A capacitor comprising: a plurality of non-capacitor openings formed in dielectric, each non-capacitor opening with a prescribed spacing between nearest neighboring non-capacitor openings in same metal line level;a plurality of capacitor openings formed in said dielectric in said same metal line level as said plurality of non-capacitor openings, each capacitor opening with a spacing between nearest neighboring capacitor openings that is less than said prescribed spacing between nearest neighboring non-capacitor openings.

16. A capacitor as in claim 15, said capacitor openings with a depth greater than depth of non-capacitor openings that are formed in said same metal wiring level.

17. A capacitor as in claim 15, said capacitor openings with a width greater than width of non-capacitor openings that are formed in said same metal wiring level.

18. A capacitor as in claim 15, said dielectric one of SiCOH and porous SiCOH.

19. A capacitor as in claim 15, said capacitor opening spacing with a maximum minimum spacing between nearest neighboring capacitor openings occurring substantially at top of said capacitor opening.

20. A capacitor as in claim 15, said capacitor opening spacing with a maximum minimum spacing between nearest neighboring capacitor openings occurring substantially at midpoint of said capacitor opening.

21. A capacitor as in claim 15, said capacitor openings comprise an interconnect portion and a via portion.

22. A capacitor as in claim 21, said capacitor openings comprise at least one stack of capacitor openings with an interconnect portion and via portion connected to another stack of capacitor openings.

23. A method for creating a capacitor, comprising the steps of: depositing a low-k dielectric;forming a plurality of openings in said low-k dielectric, at least one opening a non-capacitor opening and at least one opening a capacitor opening;protecting any non-capacitor opening from dielectric constant modification;creating a porous region along surfaces of said at least one capacitor opening;expanding said at least one capacitor opening by selectively removing said modified dielectric along said surfaces of said at least one capacitor opening; and,filling said non-capacitor opening and said expanded capacitor opening with a conductive material.

24. A method as in claim 23, said low-k dielectric is SiCOH.

25. A method as in claim 23, said modified dielectric along said surfaces of said at least one capacitor opening removed with a diluted hydrofluoric acid.

26. A method as in claim 23, said creating step comprising depleting carbon from said surfaces of said at least one capacitor opening.

27. A method as in claim 26, said depleting comprising activating an oxidizing plasma, said activating plasma one of O2, N2O, and H2O.

28. A method as in claim 26, said depleting step comprising activating a reducing plasma, said reducing plasma one of N2/H2 and H2.

29. A method for creating a capacitor, comprising the steps of: depositing a low-k dielectric comprising a dielectric matrix and porogen;removing said porogen from said low-k dielectric;forming a plurality of openings in said porous dielectric, at least one opening a non-capacitor opening and at least one opening a capacitor opening;protecting any non-capacitor opening from dielectric constant modification; and,infusing said porous dielectric along surfaces of said capacitor opening with a material having a dielectric constant higher than said dielectric constant of said porous dielectric prior to said infusion.

30. A method as in claim 29, said removing step comprising: depleting carbon from said low-k dielectric.

31. A method as in claim 29, said low-k dielectric comprises SiCOH.

32. A method as in claim 29, said low-k dielectric having a dielectric constant less than 3.0, said porous dielectric with a dielectric constant between 4.0 and 5.0.

33. A method as in claim 29, said porous dielectric infused by one of one of PVD, CVD, IPVD, and ALD.

34. A method as in claim 29, said material comprises one of a metallic material and an insulating material.

35. A method as in claim 30, said depleting step comprising activating an oxidizing plasma, said activating plasma one of O2, N2O, and H2O.

36. A method as in claim 30, said depleting step comprising activating a reducing plasma, said reducing plasma one of N2/H2 and H2.

37. A method for creating a capacitor, comprising the steps of: depositing a low-k dielectric comprising a porogen;forming a plurality of openings in said low-k dielectric, at least one opening a non-capacitor opening and at least one opening a capacitor opening;protecting any non-capacitor opening from dielectric constant fluctuation; and,infusing said porous dielectric along surfaces of said at least one capacitor opening with a material having a dielectric constant higher than said dielectric constant of said porous dielectric prior to said infusion;filling said non-capacitor and capacitor openings with a conductive material; and,removing porogen from said low-k dielectric.

38. A method as in claim 37, said removing step comprising: depleting carbon from said low-k dielectric.

39. A method as in claim 37, said low-k dielectric comprising SiCOH.

40. A method as in claim 37, said porous dielectric infused by one of one of PVD, CVD, IPVD, and ALD.

41. A method as in claim 37, said low-k dielectric having a dielectric constant less than 3.0, said porous dielectric with a dielectric constant between 4.0 and 5.0.

42. A method as in claim 37, said material comprises one of a metallic material and an insulating material.

43. A method as in claim 38, said depleting step comprising activating an oxidizing plasma, said activating plasma one of O2, N2O, and H2O.

44. A method as in claim 38, said depleting step comprising activating a reducing plasma, said reducing plasma one of N2/H2 and H2.