Systems and methods to retard copper diffusion and improve film adhesion for a dielectric barrier on copper

• US 6,764,952 B1
• Filed: 03/13/2002
• Issued: 07/20/2004
• Est. Priority Date: 03/13/2002
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (LAM Research Corporation)
• Original Assignee: Novellus Systems Incorporated (LAM Research Corporation)
• Inventors: Gupta, Atul, Nag, Somnath, Jain, Sanjeev, Yu, Jengyi, Fu, Haiying, Wong, Ka Shun, Van Schravendijk, Bart J.
• Primary Examiner(s): Gurley, Lynne
• Application Number:
  US10/099,232
• Time in Patent Office: 860 Days
• Field of Search: 438/687, 438/778, 438/791, 438/958
• US Class Current: 438/687
• CPC Class Codes: C23C 16/325 Silicon carbide
• 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 21/02211 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 21/02304 formation of intermediate layers, e.g. buffer layers, layers to improve adhesion, lattice match or diffusion barriers
• CPC Class Codes: H01L 21/28525 the conductive layers comprising semiconducting material H01L21/28518, H01L21/28537 take precedence
• CPC Class Codes: H01L 21/314 Inorganic layers H01L21/3105, H01L21/32 take precedence
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: Y10S 438/958 Passivation layer

Abstract

Two sequential treatments within a chemical vapor deposition chamber, or within sequential chambers without a vacuum break, are performed on a copper layer to clean and passivate the copper surface prior to deposition of a copper diffusion barrier layer or a dielectric layer. The first treatment includes an ammonia, a hydrogen, or a hydrocarbon plasma cleaning of the copper surface followed by a short initiation of an organosilane precursor or a thin silicon nitride layer. A copper diffusion barrier layer may then be formed over the pretreated copper surface using an organosilane plasma, with or without a carbon dioxide or a carbon monoxide, or a silane with a nitrogen gas and an ammonia gas. Copper diffusion is retarded and film adhesion is improved for a dielectric layer or a copper diffusion barrier layer on the copper surface.

Claims

1. A method of treating a copper layer of a semiconductor device, the method comprising:

placing the copper layer in a chemical vapor deposition chamber;

forming a first plasma in the chemical vapor deposition chamber;

exposing the copper layer to the first plasma; and

exposing the copper layer to a second plasma to form a passivation layer approximately 30 angstroms to 200 angstroms thick on the copper layer, the second plasma comprising a silane.

2. The method of claim 1, wherein the second plasma is formed in a second chemical vapor deposition chamber.

3. The method of claim 2, wherein a vacuum is maintained during transport of the copper layer from the first chemical vapor deposition chamber to the second chemical vapor deposition chamber.

4. The method of claim 1, wherein the chemical vapor deposition chamber is at least one of a plasma enhanced chemical vapor deposition chamber or a high density plasma chemical vapor deposition chamber.

5. The method of claim 1, wherein the step of forming the first plasma comprises introducing into the chemical vapor deposition chamber at least one of an ammonia gas, a hydrogen gas, or a hydrocarbon gas.

6. The method of claim 5, wherein a flow rate of at least one of the ammonia gas, the hydrogen gas or the hydrocarbon gas is between approximately 2000 and 6000 sccm.

7. The method of claim 6, wherein the chemical vapor deposition chamber, for the first plasma, has a radio frequency power density per shower head between approximately 100 and 500 watts at a pressure between approximately 1 and 5 Torr for a duration between approximately 3 and 120 seconds.

8. The method of claim 1, wherein the exposing step comprises introducing into the chemical vapor deposition chamber a silane gas, a nitrogen gas, and an ammonia gas.

9. The method of claim 1, further comprising depositing a copper diffusion barrier layer and an etch stop layer onto the copper layer after the copper layer is passivated.

10. The method of claim 9, wherein the copper diffusion barrier layer and the etch stop layer are at least 50 Å

thick.

11. The method of claim 9, wherein the copper diffusion barrier layer and the etch stop layer comprise at least one of a silicon nitride and a silicon carbide.

12. The method of claim 9, wherein the copper diffusion barrier layer is deposited by introducing into the chemical vapor deposition chamber an organosilane gas.

13. The method of claim 12, wherein the copper diffusion barrier layer is deposited by further introducing into the chemical vapor deposition chamber at least one of a carbon dioxide gas and a carbon monoxide gas.

14. The method of claim 9, wherein the copper diffusion barrier layer is deposited by introducing into the chemical vapor deposition chamber a silane gas with a nitrogen gas and an ammonia gas.

15. The method of claim 1, further comprising depositing a dielectric layer onto the semiconductor device after exposing the copper layer to the second plasma.

17. The method of claim 6, further comprising introducing an organosilane gas into the first or second chemical vapor deposition chamber to deposit a copper diffusion barrier layer.

18. The method of claim 17, further comprising introducing at least one of a carbon dioxide gas and a carbon monoxide gas into the first or second chemical vapor deposition chamber to deposit a copper diffusion barrier layer.

16. A method of semiconductor processing, the method comprising:

introducing at least one of an ammonia gas, a hydrogen gas, or a hydrocarbon gas into a first chemical vapor deposition chamber to clean a copper layer of a semiconductor device; and

introducing a silane gas into the first chemical vapor deposition chamber or a second chemical vapor deposition chamber, after the copper layer is cleaned to form a passivation layer approximately 30 Å

to 200 Å

thick upon the copper layer, wherein the copper layer is transported from the first chemical vapor deposition chamber to the second chemical vapor deposition chamber while maintaining a vacuum surrounding the copper layer if the second chemical vapor deposition chamber is utilized.

19. The method of claim 16, further comprising depositing a dielectric layer onto the semiconductor device after the passivation layer is formed.

20. The method of claim 16, wherein the first and second chemical vapor deposition chambers are plasma enhanced chemical vapor deposition chambers.

21. A method of treating a copper layer of a semiconductor device, the method comprising:

placing the copper layer in a chemical vapor deposition chamber;

forming a first plasma in the chemical vapor deposition chamber;

exposing the copper layer to the first plasma; and

exposing the copper layer to a second plasma to form a passivation layer approximately 10 angstroms to 200 angstroms thick on the copper layer, the second plasma comprising an organosilane.

22. The method of claim 21, wherein the exposing step comprises introducing into the chemical vapor deposition chamber at least one of a trimethylsilane gas, a tetramethylsilane gas, a trimethylsilyl acetylene gas, a trimethylvinylsilane gas, a trimethylsilyl propyne gas, and a phenyl trimethylsilane gas.

23. The method of claim 22, wherein the exposing step further comprises introducing into the chemical vapor deposition chamber a nitrogen gas and an ammonia gas.

24. The method of claim 21, wherein the exposing step is performed at a flow rate between approximately 200 and 1500 sccm with a radio frequency power density per shower head between approximately 100 and 300 watts and a pressure between approximately 1 and 5 Torr for a duration between approximately 1 and 5 seconds.

25. A method of semiconductor processing, the method comprising:

introducing at least one of an ammonia gas, a hydrogen gas, or a hydrocarbon gas into a first chemical vapor deposition chamber to clean a copper layer of a semiconductor device; and

introducing an organosilane gas into the first chemical vapor deposition chamber or a second chemical vapor deposition chamber after the copper layer is cleaned to form a passivation layer approximately 10 Å

to 200 Å

thick upon the copper layer, wherein the copper layer is transported from the first chemical vapor deposition chamber to the second chemical vapor deposition chamber while maintaining a vacuum surrounding the copper layer if the second chemical vapor deposition chamber is utilized.