LOW LEAKAGE CURRENT SILICON CARBONITRIDE PREPARED USING METHANE, AMMONIA AND SILANE FOR COPPER DIFFUSION BARRIER, ETCHSTOP AND PASSIVATION APPLICATIONS

• US 20020027286A1
• Filed: 09/30/1999
• Published: 03/07/2002
• Est. Priority Date: 09/30/1999
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: SUNDARARAJAN, SRINIVASAN, TRIVEDI, MAYUR
• Granted Patent: US 6,593,653 B2
• Time in Patent Office: Days
• US Class Current: 257/751
• 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 21/314 Inorganic layers H01L21/3105, H01L21/32 take precedence
• CPC Class Codes: H01L 21/3146 Carbon layers, e.g. diamond-like layers
• CPC Class Codes: H01L 21/318 composed of nitrides
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 23/53209 based on metals, e.g. alloys, metal silicides H01L23/53285 takes precedence
• CPC Class Codes: H01L 23/53271 containing semiconductor material, e.g. polysilicon
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A silicon carbon nitride (SiCN) layer is provided which has a low leakage current and is effective in preventing the migration or diffusion of metal or copper atoms through the SiCN layer. The SiCN layer can be used as a diffusion barrier between a metal portion (such as a copper line or via) and an insulating dielectric to prevent metal atom diffusion into the dielectric. The SiCN layer can also be used as an etchstop or passivation layer. The SiCN layer can be applied in a variety ways, including PECVD (e.g., using SiH₄, CH₄, and NH₃) and HDP CVD (e.g., using SiH₄, C₂H₂, and N₂)

Claims

1. A semiconductor device, comprising:

a metal portion providing electrical connections to underlying layers;

a silicon carbon nitride (SiCN) layer overlying the metal portion; and

a dielectric layer overlying the SiCN layer.

2. The device of claim 1, wherein the SiCN layer is a diffusion barrier.

3. The device of claim 1, further comprising a second SiCN layer used as a passivation layer overlying the dielectric layer.

4. The device of claim 1, wherein the SiCN layer is formed with a PECVD process.

5. The device of claim 4, wherein the SiCN layer is formed from SiH₄, CH₄, and NH₃ gases.

6. The device of claim 4, wherein the SiCN layer is formed from methylsilane and NH₃ gases.

7. The device of claim 1, wherein the SICN layer is formed with an HDP CVD process.

8. The device of claim 7, wherein the SiCN layer is formed from SiH₄, C₂H₂, and N₂ gases.

9. The device of claim 7, wherein the SiCN layer is formed from SiH₄, CH₄, and N₂ gases.

10. The device of claim 1, wherein the metal portion is formed from copper.

11. The device of claim 1, wherein the metal portion is a two-step connection having a line portion and a via portion.

12. The device of claim 11, wherein the two-step connection is formed in the dielectric layer.

13. The device of claim 12, further comprising a second SiCN layer on top of the two-step connection and the dielectric layer.

14. The device of claim 11, further comprising a second SiCN layer between the line portion and the via portion.

16. The method of claim 15, wherein depositing the SiCN layer is performed in a PECVD chamber.

17. The method of claim 15, wherein the SiCN layer is formed from SiH₄, CH₄, and NH₃ gases.

18. The method of claim 15, wherein the SiCN layer is formed from methylsilane and NH₃ gases.

19. The method of claim 15, wherein depositing the SiCN layer is formed in a HDP deposition chamber.

20. The method of claim 19, wherein the SiCN layer is formed from SiH₄, C₂H₂, and N₂ gases.

21. The method of claim 19, wherein the SiCN layer is formed from SiH₄, CH₄, and N₂ gases.

22. The method of claim 15, wherein the metal portion is formed of copper.

23. The method of claim 15, wherein forming the metal portion comprises:

etching the dielectric layer to form a trench region and a via region; and

depositing copper into the trench and via regions.

24. The method of claim 15, wherein depositing the dielectric layer comprises depositing a first dielectric layer and then depositing a second dielectric layer.

25. The method of claim 24, further comprising forming a via in the first dielectric layer and then forming a line in the second dielectric layer.

26. The method of claim 25, further comprising depositing a second SICN layer between the first and second dielectric layers.

27. The method of claim 22, further comprising, after forming the metal portion, removing any Cu oxide by:

introducing NH₃ or H₂ feed gas into a PECVD chamber, wherein the flow rate of the NH3 or H₂ feed gas is between approximately 50 and 8000 sccm, and the high frequency and low frequency RF power are between 50 and 4000 W.

28. The method of claim 22, further comprising, after forming the metal portion, removing any Cu oxide by:

introducing H₂ feed gas into an HDP chamber, wherein the flow rate of the H₂ feed gas is between approximately 0 and 2000 sccm, and the low frequency RF power is between 500 and 4000 W.

30. The method of claim 29, wherein the processing residue is CMP residue.

31. The method of claim 30, wherein the CMP residue is copper oxide.

15. A method of forming a semiconductor device, comprising:

forming a metal portion over underlying connections;

depositing a silicon carbon nitride (SiCN) layer over the metal portion; and

depositing a dielectric layer over the SiCN layer.

29. A method of cleaning processing residue, comprising:

introducing NH₃ or H₂ feed gas into a PECVD chamber, wherein the flow rate of the NH₃ or H₂ feed gas is between approximately 50 and 8000 sccm, and the high frequency and low frequency RF power are between 50 and 4000 W.

32. A method of cleaning processing residue, comprising:

introducing H₂ feed gas into an HDP chamber, wherein the flow rate of the H₂ feed gas is between approximately 0 and 2000 sccm, and the low frequency RF power is between 500 and 4000 W.

33. The method of claim 32, wherein the processing residue is CMP residue.

34. The method of claim 33, wherein the CMP residue is copper oxide and organics from CMP and clean.

35. The method of claim 32, wherein the processing residue is etch residue.