Method to form a robust TiCI4 based CVD TiN film

• US 20050112876A1
• Filed: 11/26/2003
• Published: 05/26/2005
• Est. Priority Date: 11/26/2003
• Status: Abandoned Application

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Chiang, Min-Hsiung, Wu, Chih-Ta, Lin, Kuo Yin
• Application Number:
  US10/723,237
• Publication Number:
  US 20050112876A1
• Time in Patent Office: Days
• US Class Current: 438/685
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76856 by treatment in plasmas or gaseous environments, e.g. nitriding a refractory metal liner
• CPC Class Codes: H01L 21/76862 Bombardment with particles, e.g. treatment in noble gas plasmas; UV irradiation

Abstract

A method is described for a plasma treatment of a TiCl₄ based CVD deposited TiN layer that reduces stress, lowers resistivity, and improves film stability. Resistivity is stable in an air ambient for up to 48 hours after the plasma treatment. A TiN layer is treated with a N-containing plasma that includes N₂, NH₃, or N₂H₄ at a temperature between 500° C. and 700° C. Optionally, H₂ may be added to N₂ in the plasma step which removes chloride impurities and densifies the TiN layer. The TiN layer may serve as a barrier layer, an ARC layer, or as a bottom electrode in a MIM capacitor. An improved resistance of the treated TiN layer to oxidation during formation of an oxide based insulator layer and a lower leakage current in the MIM capacitor is also achieved.

Claims

1. A method for processing a TiN layer on a substrate, comprising:

(a) providing a substrate;

(b) depositing a TiN layer with a halogen containing titanium source gas and a nitrogen source gas on said substrate in a first process chamber; and

(c) subjecting the TiN layer to a plasma treatment involving a N-containing gas.

2. The method of claim 1 wherein said nitrogen source gas is NH₃.

3. The method of claim 1 wherein said halogen containing titanium source gas is TiCl₄.

4. The method of claim 1 wherein said deposition is a chemical vapor deposition.

5. The method of claim 1 wherein the plasma treatment is performed ex-situ in a second process chamber.

6. The method of claim 1 wherein said plasma treatment comprises a N-containing gas flow rate of 500 to 2000 sccm, a chamber temperature between about 500°

C. and 700°

C., a RF power from about 400 Watts to 1000 Watts, a chamber pressure of about 1 to 10 Torr, and a process time of at least 30 seconds.

7. The method of claim 6 wherein said N-containing gas is one of N₂, NH₃, or N₂H₄.

8. The method of claim 7 further comprised of adding H₂ to N₂ during the plasma treatment.

9. The method of claim 1 further comprised of depositing a metal layer on the TiN layer after the plasma treatment and planarizing to form a contact.

10. A method for processing a TiN barrier layer on a substrate, comprising:

(a) providing a substrate with an opening formed therein, said opening has sidewalls, a top, and a bottom;

(b) depositing a TiN layer with a halogen containing titanium source gas and a nitrogen source gas in a first process chamber, said TiN layer is formed by a CVD process and forms an essentially conformal layer on the substrate and on the sidewalls and bottom of said opening;

(c) subjecting the TiN layer to a plasma treatment involving a N-containing gas; and

(d) depositing a metal layer on the plasma treated TiN layer that fills the opening.

11. The method of claim 10 further comprised of performing a planarization that makes the TiN layer and metal layer coplanar with the top of the opening.

12. The method of claim 10 wherein said substrate is comprised of a top layer which is a dielectric layer.

13. The method of claim 10 wherein said halogen containing titanium source gas is TiCl₄ and said nitrogen source gas is NH₃.

14. The method of claim 10 wherein the plasma treatment is performed ex-situ in a second process chamber.

15. The method of claim 10 wherein said plasma treatment comprises a N-containing gas flow rate of 500 to 2000 sccm, a chamber temperature between about 500°

C. and 700°

C., a RF power from about 400 Watts to 1000 Watts, a chamber pressure of about 1 to 10 Torr, and a process time of at least 30 seconds.

16. The method of claim 15 wherein said N-containing gas is one of N₂, NH₃, or N₂H₄.

17. The method of claim 16 further comprised of adding H₂ to N₂ during the plasma treatment.

18. The method of claim 10 wherein the opening is a contact hole formed above a silicide region on a transistor.

19. A method of forming a MIM capacitor, comprising:

(a) providing a substrate with a dielectric layer formed thereon;

(b) forming a contact hole in said dielectric layer, said contact hole has sidewalls, a top, and a bottom;

(c) depositing a TiN layer with a halogen containing titanium source gas and a nitrogen source gas in a first process chamber, said TiN layer is formed by a CVD process and forms an essentially conformal layer on the dielectric layer and on the sidewalls and bottom of said contact hole;

(d) subjecting the TiN layer to a plasma treatment involving a N-containing gas;

(e) etching back the TiN layer to a recessed depth within the contact hole;

(f) depositing an insulating layer on the recessed TiN layer; and

(g) depositing a metal layer on the insulating layer.

20. The method of claim 19 wherein the dielectric layer is comprised of SiO₂ or a low k dielectric material such as fluorine doped SiO₂, carbon doped SiO₂, a polysilsesquioxane, a poly(arylether), fluorinated polyimide, or benzocyclobutene and has a thickness of about 2000 to 20000 Angstroms.

21. The method of claim 19 wherein said halogen containing titanium source gas is TiCl₄ and said nitrogen source gas is NH₃.

22. The method of claim 19 wherein the TiN layer has a thickness of about 100 to 500 Angstroms.

23. The method of claim 19 wherein the plasma treatment is performed ex-situ in a second process chamber.

24. The method of claim 19 wherein said plasma treatment comprises a N-containing gas flow rate of 500 to 2000 sccm, a chamber temperature between about 500°

C. and 700°

C., a RF power from about 400 Watts to 1000 Watts, a chamber pressure of about 1 to 10 Torr, and a process time of at least 30 seconds.

25. The method of claim 24 wherein said N-containing gas is one of N₂, NH₃, or N₂H₄.

26. The method of claim 25 further comprised of adding H₂ to N₂ during the plasma treatment.

27. The method of claim 19 wherein the TiN layer is recessed to a depth of about 0 to 2000 Angstroms below the top of the contact hole.

28. The method of claim 19 wherein the insulating layer is a high k dielectric layer comprised of Ta₂O₅, TiO₂, Al₂O₃, ZrO₂, HfO₂, Y₂O₃, and La₂O₃ or a silicate, nitride, or oxynitride of Ti, Ta, Al, Zr, Hf, Y, and La.

29. The method of claim 28 further comprised of annealing the insulating layer before the metal layer is deposited by a process comprising an oxygen ambient.

30. The method of claim 19 wherein the metal layer is comprised of copper.