Methods for producing low stress porous and CDO low-K dielectric materials using precursors with organic functional groups

• US 7,923,385 B2
• Filed: 06/05/2009
• Issued: 04/12/2011
• Est. Priority Date: 03/31/2003
• Status: Expired due to Fees

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Wu, Qingguo, Fu, Haiying
• Primary Examiner(s): WILCZEWSKI, MARY A
• Application Number:
  US12/479,114
• Publication Number:
  US 20090239390A1
• Time in Patent Office: 676 Days
• Field of Search: 427/255.28, 427/255.18, 427/255.27, 427/255.37, 427/255.393, 427/387, 427/551, 427/553, 427/557, 438/507, 438/509, 438780-782, 438/787, 438/788, 438/789, 438/790, 438/783, 438/784
• US Class Current: 438/789
• 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 21/02203 the layer being porous
• 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 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass

Abstract

Methods of preparing a carbon doped oxide (CDO) layers having a low dielectric constant are provided. The methods involve, for instance, providing a substrate to a deposition chamber and exposing it to one or multiple carbon-doped oxide precursors having molecules with at least one carbon-carbon triple bond, or carbon-carbon double bond, or a combination of these groups and depositing the carbon doped oxide dielectric layer under conditions in which the resulting dielectric layer has a dielectric constant of not greater than about 2.7. Methods of preparing a low stress porous low-k dielectric material on a substrate are provided. The methods involve the use of a structure former precursor and/or porogen precursor with one or more organic functional groups. In some cases, the structure former precursor has carbon-carbon double or triple bonds. In other cases, one or both of the structure former precursor and porogen precursor has one or more bulky organic groups. In other cases, the structure former precursor has carbon-carbon double or triple bonds and one or both of the structure former precursor and porogen precursor has one or more bulky organic groups. Once the precursor film is formed, the porogen is removed, leaving a porous low-k dielectric matrix with high mechanical strength. Different types of structure former precursors and porogen precursors are described. The resulting low stress low-k porous film may be used as a low-k dielectric film in integrated circuit manufacturing applications.

Claims

1. A method of preparing a low-k dielectric on an integrated circuit substrate, the method comprising:

forming a silicon oxide based dielectric film on the substrate, the film formed by contacting the substrate with ethynyltrimethylsilane and a carrier gas comprising CO₂ in a PECVD reactor processing chamber operated at a temperature of between about 300 and 425°

C., a pressure of between about 2 and 7 Torr and a HF RF power of at least about 125 W.

2. The method of claim 1, further comprising exposing the film to a thermal, plasma, UV, e-beam or combination thereof post-formation treatment.

3. The method of claim 1, wherein the PECVD reactor processing chamber is operated at a temperature of about 400°

C.

4. The method of claim 1, wherein the PECVD reactor processing chamber is operated at a HF RF power of about 250 W.

5. The method of claim 1 wherein the PECVD reactor processing chamber comprises a showerhead and a wafer support, and wherein a gap between the showerhead and wafer support is between about 3 and 20 millimeters.

6. A method of preparing a low-k dielectric on an integrated circuit substrate, the method comprising:

forming a silicon oxide based dielectric film on the substrate, the film formed by contacting the substrate with vinyltrimethylsilane precursor and a carrier gas comprising CO₂ in a PECVD reactor processing chamber operated at a temperature of between about 300 and 425°

C., a pressure of between about 2 and 7 Torr, a HF RF power of at least about 125 W.

7. The method of claim 6, further comprising exposing the film to a thermal, plasma, UV, e-beam or combination thereof post-formation treatment.

8. The method of claim 6, wherein the PECVD reactor processing chamber is operated at a temperature of about 400°

C.

9. The method of claim 6, wherein the PECVD reactor processing chamber is operated at a HF RF power of about 125 W.

10. The method of claim 6 wherein the PECVD reactor processing chamber comprises a showerhead and a wafer support, and wherein a gap between the showerhead and wafer support is between about 3 and 20 millimeters.

11. A method of preparing a low-k dielectric on an integrated circuit substrate, the method comprising:

forming a silicon oxide based dielectric film on the substrate, the film formed by contacting the substrate with bis(trimethylsilyl)acetylene and a carrier gas comprising CO₂ in a PECVD reactor processing chamber operated at a temperature of between about 300 and 425°

C., a pressure of between about 2 and 7 Torr and a HF RF power of at least about 125 W.

12. The method of claim 11, further comprising exposing the film to a thermal, plasma, UV, e-beam or combination thereof post-formation treatment.

13. The method of claim 11 wherein the PECVD reactor processing chamber comprises a showerhead and a wafer support, and wherein a gap between the showerhead and wafer support is between about 3 and 20 millimeters.

14. A method of preparing a low-k dielectric on an integrated circuit substrate, the method comprising:

forming a silicon oxide based dielectric film on the substrate, the film formed by contacting the substrate with a silicon-containing hydrocarbon precursor selected from the group consisting of vinyltrimethylsilane, ethynyltrimethylsilane, bis(trimethylsilyl)acetylene and combinations thereof, and an oxygenated carrier gas in a PECVD reactor processing chamber operated at a temperature of between about 300 and 425°

C., a pressure of between about 0.5 and 20 Torr, and a HF RF power of between about 125 to 750 W at a frequency of between about 2 and 60 MHz.

15. The method of claim 14, wherein the precursor comprises vinyltrimethylsilane.

16. The method of claim 14, wherein the precursor comprisess ethynyltrimethylsilane.

17. The method of claim 14, wherein the precursor comprises bis(trimethylsilyl)acetylene.

18. The method of claim 14, wherein the oxygenated carrier gas is selected from the group consisting of CO₂, O₃, H₂O₂, O₂ and combinations thereof.

19. The method of claim 14, wherein the oxygenated carrier gas is CO₂.

20. The method of claim 14, wherein the PECVD reactor processing chamber is operated at a temperature of about 350 to 400°

C.

21. The method of claim 14, wherein the PECVD reactor processing chamber is operated at a temperature of about 400°

C.

22. The method of claim 14, further comprising exposing the film to a post-formation treatment selected from the group consisting of thermal, plasma, UV and e-beam treatments, and combinations thereof.

23. The method of claim 14, wherein the dielectric has a dielectric constant of less than about 2.7.

24. The method of claim 14 wherein the PECVD reactor processing chamber comprises a showerhead and a wafer support, and wherein a gap between the showerhead and wafer support is between about 3 and 20 millimeters.