Methods for improving integration performance of low stress CDO films

• US 7,326,444 B1
• Filed: 09/14/2004
• Issued: 02/05/2008
• Est. Priority Date: 09/14/2004
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Wang, Honghong, Wu, Qingguo, Fu, Haiying, Niu, Dong
• Primary Examiner(s): Chen; Bret
• Application Number:
  US10/941,502
• Time in Patent Office: 1,239 Days
• Field of Search: 427/255.29, 427/255.27, 427/255.37, 427/579
• US Class Current: 427/579
• CPC Class Codes: C23C 16/401 containing silicon
• 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 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC

Abstract

Methods of preparing a carbon doped oxide (CDO) layer with a low dielectric constant (<3) and low residual stress without sacrificing important integration properties such as dry etch rate, film stability during wet cleaning, electrical leakage current, and extinction coefficient are provided. The methods involve, for instance, providing a substrate to a deposition chamber and exposing it to a chemical precursor having molecules with at least one carbon-carbon triple bond, followed by igniting and maintaining a plasma in a deposition chamber using radio frequency power having high and low frequency components or one frequency component only, and depositing the carbon doped oxide film under conditions in which the resulting dielectric layer has a compressive stress or a tensile stress of between about −20 to 30 MPa and a dielectric constant of between about 2.5-3.0, a C≡C to SiO bond ratio of between about 0.05% to 5%, a SiC to SiO bond ratio of between about 2% to 10%, and a refractive index (RI) of 1.39-1.52 measured at 633 nm.

Claims

1. A method of preparing a carbon doped silicon oxide (CDO) film on a substrate, the method comprising:

(a) providing the substrate to a deposition chamber; and

(b) contacting the substrate with one or more CDO precursors having a carbon-carbon triple bond and with an oxidizer under process conditions whereby the CDO film is formed on the substrate, and whereby the CDO film contains carbon-carbon triple bonds and their derivative bonds;

wherein

the substrate is contacted with one or more CDO precursors having a carbon-carbon triple bond and an oxidizer in a dual frequency plasma enhanced deposition process such that CDO film has carbon-carbon triple bonds or their derivative forms in sufficient amounts that the CDO film has a compressive stress or a tensile stress of between about −

20 to 30 MPa and a dielectric constant of between about 2.5-3.0 has a cracking threshold of at least 3 um; and

wherein

the oxidizer is selected from the group consisting of O₂, N₂O, H₂O, O₃, H₂O₂, and combinations thereof.

2. The method of claim 1, wherein the substrate is a partially fabricated integrated circuit.

3. The method of claim 1, wherein the CDO film is an interlayer dielectric in an integrated circuit.

4. The method of claim 1, wherein the deposition chamber comprises one or multiple stations that allow processing one or multiple substrates in parallel.

5. The method of claim 1, wherein contacting the substrate involves contacting with a single CDO precursor in a carrier gas and an oxidizer selected from O₂, N₂O, H₂O, O₃, H₂O₂, and combinations hereof.

6. The method of claim 5, wherein the carrier gas is carbon dioxide.

7. The method of claim 5, wherein the carrier gas is supplied to the deposition chamber at a flow rate of 50-10000 sccm.

8. The method of claim 5, wherein the carrier gas is supplied to the deposition chamber at a flow rate of 3000-8000 sccm.

9. The method of claim 5, wherein the plasma is formed in a deposition chamber using six showerheads with diameter of about 200 mm, where the distance between the showerhead and the wafer is between about 10 mm and 100 mm, the HF power is 100-3000 W at about 14 MHz, and the LF power is 50-2000 W at between about 100 to 600 kHz.

10. The method of claim 5, wherein the plasma is formed in a deposition chamber using four showerheads with diameter of about 300 mm, wherein the distance between the showerhead and the wafer is between about 10 mm and 100 ml, the HF power is 100-4000 W at about 14 MHz, and the LF power is 50-2000 W at between about 100 to 600 kHz.

11. The method of claim 5, wherein the plasma density is between about 0.05 W/cm² and 2 W/cm².

12. The method of claims 9, 10, or 11, wherein the oxidizer and the CDO precursor are supplied to the deposition chamber such that the ratio of oxidizer to CDO precursor is between 10 sccm:

1 ccm and 500 sccm;

1 ccm.

13. The method of claim 5, wherein the CDO precursor is supplied to the deposition chamber at a flow rate of about 0.5-10 ccm.

14. The method of claim 13, wherein the oxidizer is supplied to the deposition chamber at a flow rate of between about 50 to 500 sccm.

15. The method of claim 5, wherein the CDO precursor is supplied to the deposition chamber at a flow rate of about 2-3 ccm.

16. The method of claim 15, wherein the oxidizer is supplied to the deposition chamber at a flow rate of between about 100 to 250 sccm.

17. The method of claim 16, wherein the oxidizer is supplied to the deposition chamber at a flow rate of between about 150 to 200 sccm.

18. The method of claim 17, wherein the oxidizer is supplied to the deposition chamber at a flow rate of about 150 sccm.

19. The method of claim 1, wherein the one or more CDO precursors are provided in a carrier gas.

20. The method of claim 1, wherein the CDO precursor comprises one or more compounds selected from the group consisting of Ethynyltrimethylsilane (ETMS), also known as trimethylsilaneacetylene (TMSA), Bis(trimethylsilyl)acetylene (BTMSA), dimethylmethoxysilaneacetylene (DMMOSA) and dimethylsilane-diacetylene (DMSDA).

21. The method of claim 1, wherein the CDO precursor comprises one or more compounds selected from the group consisting of Ethynyltrimethylsilane (EMS), also known as trimethylsilaneacetylene (TMSA), and Bis(trimethylsilyl)acetylene (BTMSA).

22. The method of claim 1, wherein the oxidizer is selected from the group consisting of O₂ and H₂O₂.

23. The method of claim 1, wherein the deposited CDO film has a C≡

C to SiO bond ratio of between about 0.05% to 5%.

24. The method of claim 1, wherein the deposited CDO film has a SiC to SiO bond ratio of between about 2% to 10%.

25. The method of claim 1, wherein the deposited CDO film has refractive index (RI) of 1.39-1.52 measured at 633 nm.

26. The method of claim 1, wherein the CDO dielectric layer has a modulus of not less than about 6 GPa.

27. The method of claim 1, wherein the CDO dielectric layer has a modulus of between about 8 and 15 GPa.

28. The method of claim 1, wherein the deposition pressure is maintained at a pressure of between about 0.1 to 20 Torr.

29. The method of claim 1, wherein the deposition pressure is maintained at a pressure of between about 2.5-10 Torr.