Plasma treatment to enhance inorganic dielectric adhesion to copper

• US 6,255,217 B1
• Filed: 01/04/1999
• Issued: 07/03/2001
• Est. Priority Date: 01/04/1999
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Stamper, Anthony K., Agnello, Paul D., Buchwalter, Leena P., Hummel, John, Luther, Barbara
• Primary Examiner(s): Picardat, Kevin M.
• Assistant Examiner(s): COLLINS, DEVEN M
• Application Number:
  US09/225,530
• Time in Patent Office: 911 Days
• Field of Search: 438/687, 438/584, 438/597, 438/106, 438/618, 438/624, 438/637
• US Class Current: 438/687
• CPC Class Codes: H01L 21/02115 the material being carbon, e.g. alpha-C, diamond or hydrogen doped carbon
• CPC Class Codes: H01L 21/0212 the material being fluoro carbon compounds, e.g.(CFx) n, (CHxFy) n or polytetrafluoroethylene
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02167 the material being a silicon carbide not containing oxygen, e.g. SiC, SiC:H or silicon carbonitrides H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0445 the devices having semiconductor bodies comprising crystalline silicon carbide multistep processes for the manufacture of said devices H01L29/66053
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 21/76801 characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
• CPC Class Codes: H01L 21/76807 for dual damascene structures
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence

Abstract

The present invention utilizes a reducing plasma treatment step to enhance the adhesion of a subsequently deposited inorganic barrier film to a copper wire or via present in a semiconductor interconnect structure such as a dual damascene structure.

Claims

1. A method of facilitating the adhesion of an inorganic barrier film formed on an copper interconnect structure, said method comprising the steps of:

(a) exposing an interconnect semiconductor structure containing at least a layer of copper to a reducing plasma; and

(b) forming an inorganic barrier film on said plasma exposed copper interconnect structure, wherein said exposing step improves the adhesion of said inorganic barrier film to a copper surface of said copper interconnect structure.

2. The method of claim 1 wherein said exposure step is carried out in a non-oxidizing plasma ambient selected from the group consisting of H₂, N₂, NH₃, noble gases and mixtures thereof.

3. The method of claim 2 wherein said non-oxidizing plasma ambient is H₂.

4. The method of claim 2 wherein said non-oxidizing plasma ambient is NH₃.

5. The method of claim 1 wherein said exposure step is carried out at a temperature of from about 20°

to about 600°

C. for a time period of from about 1 to about 3600 seconds or higher.

6. The method of claim 5 wherein said exposure step is carried out at a temperature of from about 360°

to about 400°

C. for a time period of from about 5 to about 30 seconds.

7. The method of claim 1 wherein said exposure step is conducted at a pressure of from about 1 mTorr to about 20 Torr, a power of from about 50 to about 10,000 watts, and a gas flow rate of from about 1 to about 10,000 sccm.

8. The method of claim 1 wherein said exposure step is carried out by high density plasma chemical vapor deposition at a pressure of from about 3 to about 6 mTorr, a power of from about 1500 to about 3000 watts, and a gas flow rate of from about 10 to about 50 sccm.

9. The method of claim 1 wherein said exposure step is carried out by plasma enhanced chemical vapor deposition at a pressure of from about 2 to about 8 Torr, a power of from about 150 to 400 watts and a gas flow rate of from about 100 to about 2000 sccm.

10. The method of claim 1 wherein said copper interconnect structure is a capacitor structure, a damascene structure or multiple wiring levels containing a plurality of vias and metal lines.

11. The method of claim 10 wherein said copper interconnect structure is a single or dual damascene structure containing copper lines and vias.

12. The method of claim 1 wherein said inorganic barrier film is formed in-situ utilizing a deposition process selected from the group consisting of chemical vapor deposition, low pressure chemical vapor deposition, plasma enhanced chemical vapor deposition and high density plasma chemical vapor deposition.

13. The method of claim 12 wherein said inorganic barrier film is formed in-situ by plasma enhanced chemical vapor deposition or high density plasma chemical vapor deposition.

14. The method of claim 1 wherein said inorganic barrier film is composed of Si₃N₄, SiC, hydrogenated Si₃N₄ or hydrogenated SiC.

15. The method of claim 14 wherein said inorganic barrier film is hydrogenated Si₃N₄ or hydrogenated SiC.

16. The method of claim 1 wherein said interconnect structure includes a dielectric material selected from the group consisting of SiO₂, fluorinated SiO₂, Si₃N₄, polyimides, diamond, diamond-like carbon, silicon polymers, paralyne polymers and fluorinated diamond-like carbon.

17. The method of claim 16 wherein said dielectric material is SiO₂.

18. The method of claim 1 wherein said layer of Cu is formed inside a trench.