Structures based on ceramic tantalum nitride

• US 6,836,400 B2
• Filed: 01/16/2001
• Issued: 12/28/2004
• Est. Priority Date: 02/24/2000
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Newport Fab, LLC (Tower Semiconductor Limited)
• Inventors: Abdul-Ridha, Hadi, Young, David T., Brongo, Maureen R.
• Primary Examiner(s): Reichard, Dean A.
• Assistant Examiner(s): Ha, Nguyen T.
• Application Number:
  US09/761,489
• Publication Number:
  US 20010017757A1
• Time in Patent Office: 1,442 Days
• Field of Search: 361/311, 361/312, 361/313, 361/306.1, 361/306.3, 361/308.2, 361/308.3, 361/321.1, 361/321.2, 361/301.2, 361/303, 361/321.5, 361/305, 361/306.2, 361/321.4, 438/396
• US Class Current: 361/311
• CPC Class Codes: C23C 14/0036 Reactive sputtering
• CPC Class Codes: C23C 14/0641 Nitrides C23C14/0617 takes precedence
• CPC Class Codes: H01L 21/28568 the conductive layers comprising transition metals H01L21/28518 takes precedence

Abstract

A method for fabrication of ceramic tantalum nitride and improved structures based thereon is disclosed. According to the disclosed method, an ionized metal plasma (“IMP”) tool is used to create a plasma containing tantalum ions where the plasma is sustained by a mixture of nitrogen and argon gases. The percentage of nitrogen partial flow in the mixture of gases is adjusted so as to result in a layer of tantalum nitride with a nitrogen content of at least 30%. With a nitrogen content of at least 30%, the tantalum nitride becomes ceramic. The ceramic tantalum nitride presents a number of advantages. For example, the fabrication of ceramic tantalum nitride can be easily incorporated into fabrication of semiconductor chips using copper as the interconnect metal. Also, ceramic tantalum nitride can be used as an effective etch stop layer. The reason is that ceramic tantalum nitride does not react with fluoride which is a typical constituent of etchants utilized to etch silicon-based dielectrics such as silicon dioxide. Further, ceramic tantalum nitride can be used as a dielectric in fabrication of a capacitor stack using copper electrodes. Since fabrication of ceramic tantalum nitride is easily assimilated with fabrication of copper, the capacitor stack utilizing ceramic tantalum nitride can be built in a single IMP tool along with the copper electrodes. The result is higher throughput and a reduced risk of contaminating the semiconductor wafer since there is no need to “break vacuum” for a separate fabrication of the dielectric layer.

Claims

1. A structure comprising:

a first capacitor electrode;

a second capacitor electrode;

a dielectric comprising ceramic tantalum nitride situated between said first and second capacitor electrodes, said dielectric comprising ceramic tantalum nitride having a nitrogen content of at least 30%;

a first and a second layer of metallic tantalum nitride, said first layer of metallic tantalum nitride being situated between said dielectric comprising ceramic tantalum nitride and said first capacitor electrode and said second layer of metallic tantalum nitride being situated between said dielectric comprising ceramic tantalum nitride and said second capacitor electrode.

2. The structure of claim 1 wherein said first capacitor electrode is made of copper.

3. The structure of claim 1 wherein said second capacitor electrode is made of copper.

4. The structure of claim 1 wherein said dielectric comprising ceramic tantalum nitride is fabricated using a method comprising the steps of:

utilizing an ionized metal plasma tool for creating a plasma containing tantalum ions, said plasma being sustained by a mixture of gases containing nitrogen;

depositing said dielectric comprising ceramic tantalum nitride on said first capacitor electrode wherein a percentage of nitrogen partial flow in said mixture of gases is adjusted so as to cause said nitrogen content in said dielectric comprising ceramic tantalum nitride to be at least 30%.

5. The structure of claim 4 wherein said percentage of nitrogen partial flow in said mixture of gases is adjusted so as to cause said nitrogen content in said dielectric comprising ceramic tantalum nitride to be 60%.

6. A structure comprising:

a first capacitor electrode comprising a bottom copper interconnect metal segment;

a first barrier layer over said bottom copper interconnect metal segment;

a copper seed layer over said first barrier layer;

a dielectric comprising tantalum nitride over said copper seed layer;

a second barrier layer over said dielectric;

a second capacitor electrode comprising a top copper interconnect metal segment.

7. The structure of claim 6 wherein said structure is fabricated in a single ionized metal plasma tool.

8. The structure of claim 6 wherein said first capacitor electrode, said first barrier layer, said copper seed layer, said dielectric, said second barrier layer, and said second capacitor electrode are fabricated in a single ionized metal plasma tool.

9. The structure of claim 6 wherein said first barrier layer comprises metallic tantalum nitride.

10. The structure of claim 6 wherein said second barrier layer comprises metallic tantalum nitride.

11. The structure of claim 6 wherein said first barrier layer comprises metallic tantalum nitride having a nitrogen content of approximately 21%.

12. The structure of claim 6 wherein said second barrier layer comprises metallic tantalum nitride having a nitrogen content of approximately 21%.

13. The structure of claim 6 wherein said dielectric comprises tantalum nitride having a nitrogen content of at least 30%.

14. The structure of claim 6 wherein said dielectric comprises tantalum nitride having a nitrogen content of approximately 60%.

15. The structure of claim 6 wherein said dielectric comprises ceramic tantalum nitride.

16. The structure of claim 7 wherein a percentage of nitrogen partial flow in a mixture of gases in said ionized plasma tool is adjusted so as to cause a nitrogen content in each of said first and second barrier layers to be approximately 21%.

17. The structure of claim 7 wherein a percentage of nitrogen partial flow in a mixture of gases in said ionized plasma tool is adjusted so as to cause a nitrogen content in said dielectric to be to be at least 30%.

18. The structure of claim 7 wherein a percentage of nitrogen partial flow in a mixture of gases in said ionized plasma tool is adjusted so as to cause a nitrogen content in said dielectric to be approximately 60%.

19. A capacitor comprising:

a first capacitor electrode comprising a bottom interconnect metal segment;

a first barrier layer over said bottom interconnect metal segment;

a seed layer over said first barrier layer;

a dielectric over said seed layer;

a second barrier layer over said dielectric;

a second capacitor electrode comprising a top interconnect metal segment, wherein said bottom interconnect metal segment, said first barrier layer, said seed layer, said dielectric, said second barrier layer, and said top interconnect metal segment are fabricated in a single tool.

20. The structure of claim 19 wherein said single tool is a single ionized metal plasma tool.

21. The structure of claim 19 wherein said bottom interconnect metal segment comprises copper.

22. The structure of claim 19 wherein said top interconnect metal segment comprises copper.

23. The structure of claim 19 wherein said first barrier layer comprises metallic tantalum nitride.

24. The structure of claim 19 wherein said second barrier layer comprises metallic tantalum nitride.

25. The structure of claim 19 wherein said first barrier layer comprises metallic tantalum nitride having a nitrogen content of approximately 21%.

26. The structure of claim 19 wherein said second barrier layer comprises metallic tantalum nitride having a nitrogen content of approximately 21%.

27. The structure of claim 19 wherein said dielectric comprises tantalum nitride having a nitrogen content of at least 30%.

28. The structure of claim 19 wherein said dielectric comprises tantalum nitride having a nitrogen content of approximately 60%.

29. The structure of claim 19 wherein said dielectric comprises ceramic tantalum nitride.

30. The structure of claim 20 wherein a percentage of nitrogen partial flow in a mixture of gases in said ionized plasma tool is adjusted so as to cause a nitrogen content in each of said first and second barrier layers to be approximately 21%.

31. The structure of claim 20 wherein a percentage of nitrogen partial flow in a mixture of gases in said ionized plasma tool is adjusted so as to cause a nitrogen content in said dielectric to be at least 30%.

32. The structure of claim 20 wherein a percentage of nitrogen partial flow in a mixture of gases in said ionized plasma tool is adjusted so as to cause a nitrogen content in said dielectric to be approximately 60%.