Method for making an integrated circuit capacitor including tantalum pentoxide

• US 6,265,260 B1
• Filed: 06/30/1999
• Issued: 07/24/2001
• Est. Priority Date: 01/12/1999
• Status: Expired due to Term

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Roy, Pradip Kumar, Alers, Glenn B.
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): KESHAVAN, BELUR V
• Application Number:
  US09/345,556
• Time in Patent Office: 755 Days
• Field of Search: 438/240, 438/238, 438/243, 438/398, 438/396, 438/253, 438/386, 257/310
• US Class Current: 438/240
• CPC Class Codes: H01L 21/02183 the material containing tantalum, e.g. Ta2O5
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/31604 Deposition from a gas or vapour H01L21/31691, H01L21/31695 take precedence
• CPC Class Codes: H01L 28/40 Capacitors

Abstract

A method for making an integrated circuit capacitor which in one embodiment preferably comprises the steps of: forming, adjacent a semiconductor substrate, a first metal electrode comprising a metal nitride surface portion; forming a tantalum pentoxide layer on the metal nitride surface portion while maintaining a temperature below an oxidizing temperature of the metal; remote plasma annealing the tantalum pentoxide layer; and forming a second electrode adjacent the tantalum pentoxide layer. The step of forming the tantalum pentoxide layer preferably comprises chemical vapor deposition of the tantalum pentoxide at a temperature below about 500° C. Accordingly, oxidation of the metal is avoided and a high quality tantalum pentoxide is produced. The metal of the first metal electrode may comprise at least one of titanium, tungsten, tantalum, and alloys thereof.

Claims

1. A method for making an integrated circuit capacitor comprising the steps of:

forming a first metal electrode adjacent a semiconductor substrate;

forming a tantalum pentoxide layer on the first metal electrode while maintaining a temperature below an oxidizing temperature thereof;

performing at least one remote plasma anneal of the tantalum pentoxide layer while maintaining a temperature below the oxidizing temperature of the first metal electrode; and

forming a second electrode adjacent the tantalum pentoxide layer after the step of annealing and while maintaining a temperature below the oxidizing temperature of the first metal electrode.

2. A method according to claim 1 wherein the step of forming the tantalum pentoxide layer comprises chemical vapor deposition thereof at a temperature below about 500°

C.

3. A method according to claim 1 wherein the step of forming the tantalum pentoxide layer comprises chemical vapor deposition thereof at a temperature below about 400°

C.

4. A method according to claim 1 wherein the step of forming the tantalum pentoxide layer further comprises forming the tantalum pentoxide layer in a time of less than about 10 minutes.

5. A method according to claim 1 wherein the step of forming the tantalum pentoxide layer further comprises forming the tantalum pentoxide layer at a pressure of greater than about 3 Torr.

6. A method according to claim 1 wherein the step of performing at least one remote plasma anneal comprises exposing the tantalum pentoxide layer to a pure nitrogen containing remote plasma.

7. A method according to claim 6 wherein the step of performing at least one remote plasma anneal comprises exposing the tantalum pentoxide layer to an oxygen and nitrogen containing remote plasma after the pure nitrogen remote plasma anneal.

8. A method according to claim 1 wherein the step of forming the first metal electrode comprises forming the first metal electrode to include at least one of titanium, tungsten, tantalum, and alloys thereof.

9. A method according to claim 1 wherein the step of forming the first metal electrode comprises forming the first metal electrode to include at least one of titanium, tungsten, tantalum, platinum, ruthenium, iridium, and alloys thereof.

10. A method according to claim 1 wherein the step of forming the second electrode comprises forming a second metal electrode.

11. A method according to claim 1 further comprising the steps of:

forming at least one dielectric layer adjacent the semiconductor substrate; and

forming an opening in the at least one dielectric layer; and

wherein the step of forming the first metal electrode comprises forming the first metal electrode to line the opening in the at least one dielectric layer.

12. A method according to claim 1 wherein the step of forming the first metal electrode comprises the steps of forming a first metal layer and nitridizing an upper surface portion thereof.

13. A method according to claim 12 wherein the step of nitridizing comprises exposing the first metal layer to a nitrogen containing ambient while maintaining a temperature below the oxidizing temperature of the metal.

14. A method according to claim 1 wherein the step of forming the first metal layer electrode comprises depositing a first metal layer and depositing a metal nitride layer thereon while maintaining a temperature below the oxidizing temperature of the metal.

15. A method for making an integrated circuit capacitor comprising the steps of:

forming a first metal electrode adjacent a semiconductor substrate;

forming a tantalum pentoxide layer on the first electrode while maintaining a temperature below about 500°

C. for a time period of less than about 10 minutes;

performing at least one remote plasma anneal of the tantalum pentoxide layer while maintaining a temperature below about 500°

C.; and

forming a second electrode adjacent the tantalum pentoxide layer after the step of annealing and while maintaining a temperature below about 500°

C.

16. A method according to claim 15 wherein the step of forming the tantalum pentoxide layer comprises chemical vapor deposition thereof at a temperature below about 400°

C.

17. A method according to claim 15 wherein the step of performing at least one remote plasma anneal comprises exposing the tantalum pentoxide layer to a pure nitrogen containing remote plasma.

18. A method according to claim 17 wherein the step of performing at least one remote plasma anneal comprises exposing the tantalum pentoxide layer to an oxygen and nitrogen containing remote plasma after the pure nitrogen remote plasma anneal.

19. A method according to claim 15 wherein the step of forming the first metal electrode comprises forming the first metal electrode to include at least one of titanium, tungsten, tantalum, and alloys thereof.

20. A method according to claim 15 wherein the step of forming the first metal electrode comprises forming the first metal electrode to include at least one of titanium, tungsten, tantalum, platinum, ruthenium, iridium, and alloys thereof.

21. A method according to claim 15 wherein the step of forming the second electrode comprises forming a second metal electrode.

22. A method according to claim 15 further comprising the steps of:

forming at least one dielectric layer adjacent the semiconductor substrate; and

forming an opening in the at least one dielectric layer; and

wherein the step of forming the first metal electrode comprises forming the first metal electrode to line the opening in the at least one dielectric layer.

23. A method for making an integrated circuit capacitor comprising the steps of:

forming, adjacent a semiconductor substrate, a first metal electrode comprising at least one of titanium, tungsten, tantalum, and alloys thereof;

forming a tantalum pentoxide layer on the first metal electrode while maintaining a temperature below about 500°

C.;

remote plasma annealing the tantalum pentoxide layer in a pure nitrogen plasma;

remote plasma annealing the tantalum pentoxide layer in a nitrogen and oxygen plasma after the pure nitrogen anneal; and

forming a second electrode adjacent the tantalum pentoxide layer after the remote plasma annealing in the nitrogen and oxygen plasma.

24. A method according to claim 23 wherein the step of forming the tantalum pentoxide layer comprises chemical vapor deposition thereof at a temperature below about 400°

C.

25. A method according to claim 23 wherein the step of forming the tantalum pentoxide layer further comprises forming the tantalum pentoxide layer in a time of less than about 10 minutes.

26. A method according to claim 23 wherein the step of forming the second electrode comprises forming a second metal electrode.

27. A method according to claim 23 further comprising the steps of:

forming at least one dielectric layer adjacent the semiconductor substrate; and

forming an opening in the at least one dielectric layer;

wherein the step of forming the first metal electrode comprises forming the first metal electrode to line the opening in the at least one dielectric layer.