Plasma treatment for copper oxide reduction

• US 6,734,102 B2
• Filed: 09/23/2002
• Issued: 05/11/2004
• Est. Priority Date: 11/17/1998
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Rathi, Sudha, Xu, Ping, Huang, Judy
• Primary Examiner(s): WILCZEWSKI, MARY A
• Application Number:
  US10/252,195
• Publication Number:
  US 20030022509A1
• Time in Patent Office: 596 Days
• Field of Search: 438/706, 438/687, 438/694, 438/710, 438/720, 438/787, 438/791, 438/907, 438/908, 438/963, 134/1.1
• US Class Current: 438/687
• CPC Class Codes: B08B 7/0035 by radiant energy, e.g. UV, laser, light beam or the like
• CPC Class Codes: C23C 16/0245 by etching with a plasma
• CPC Class Codes: C23G 5/00 Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/02068 during, before or after processing of conductive layers, e.g. polysilicon or amorphous silicon layers
• CPC Class Codes: H01L 21/02074 the processing being a planarization of conductive layers
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/76807 for dual damascene structures
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 21/76883 Post-treatment or after-treatment of the conductive material
• CPC Class Codes: Y10S 438/907 Continuous processing

Abstract

The present invention provides an in situ plasma reducing process to reduce oxides or other contaminants, using a compound of nitrogen and hydrogen, typically ammonia, at relatively low temperatures prior to depositing a subsequent layer thereon. The adhesion characteristics of the layers are improved and oxygen presence is reduced compared to the typical physical sputter cleaning process of an oxide layer. This process may be particularly useful for the complex requirements of a dual damascene structure, especially with copper applications.

Claims

1. A method of removing oxides on a substrate, comprising:

introducing a reducing agent comprising nitrogen and hydrogen into a chamber;

initiating a plasma consisting essentially of the reducing agent in the chamber;

exposing a copper oxide to the plasma of the reducing agent; and

then

depositing a silicon-based dielectric layer on the substrate without breaking vacuum after the copper oxide has been exposed to the plasma of the reducing agent, wherein the silicon-based dielectric layer comprises a material selected from the group of silicon carbide, silicon nitride, silicon oxide, and combinations thereof.

2. The method of claim 1, wherein the reducing agent comprises ammonia.

3. The method of claim 1, wherein a pressure in the chamber is from about 1 mTorr to about 9 mTorr.

4. The method of claim 1, wherein the plasma is initiated by providing a power density of about 1.4 watts per square centimeter to about 14.3 watts per square centimeter to the chamber.

5. The method of claim 1, wherein a substrate temperature is maintained from about 100°

C. to about 450°

C. while exposing the copper oxide to the reducing agent.

6. The method of claim 1, wherein ammonia is introduced into the chamber at a rate of about 100 sccm to about 1000 sccm.

7. The method of claim 1, further comprising introducing a carrier gas into the chamber with the reducing gas.

8. The method of claim 1, wherein a pressure in the chamber is from about 1 mTorr to about 9 mTorr, an RF generator provides a power density from about 1.4 watts per square centimeter to about 14.3 watts per square centimeter, a substrate temperature is maintained from about 100°

C. to about 450°

C., and ammonia is introduced into the chamber at a flow rate of about 100 sccm to about 1000 sccm.

9. The method of claim 8, further comprising introducing a carrier gas into the chamber with the reducing gas.

10. The method of claim 1, wherein the dielectric layer is deposited in situ on the substrate after the copper oxide has been exposed to the reducing agent.

11. A method of removing contaminants on a surface of a substrate, comprising:

initiating a plasma consisting essentially of a reducing agent comprising nitrogen and hydrogen in a chamber;

exposing at least a portion of a surface having a copper oxide contaminant to the plasma consisting essentially of the reducing agent; and

then

depositing a silicon-based dielectric layer on the substrate without breaking vacuum after the copper oxide has been exposed to the plasma of the reducing agent, wherein the silicon-based dielectric layer comprises a material selected from the group of silicon carbide, silicon nitride, silicon oxide, and combinations thereof.

12. The method of claim 11, wherein the reducing agent comprises ammonia.

13. The method of claim 11, further comprising introducing a carrier gas into the chamber with the reducing gas.

14. The method of claim 11, wherein a pressure in the chamber is from about 1 mTorr to about 9 mTorr.

15. The method of claim 11, wherein the plasma is initiated by providing a power density of about 1.4 watts per square centimeter to about 14.3 watts per square centimeter to the chamber.

16. The method of claim 11, wherein a surface temperature is maintained from about 100°

C. to about 450°

C. while exposing the copper oxide to the reducing agent.

17. The method of claim 11, wherein ammonia is introduced into the chamber at a flow rate of about 100 sccm to about 1000 sccm.

18. The method of claim 11, wherein the dielectric layer is deposited in situ on the substrate after the copper oxide has been exposed to the reducing agent.