Method for low temperature chemical vapor deposition of low-k films using selected cyclosiloxane and ozone gases for semiconductor applications

• US 7,084,079 B2
• Filed: 11/18/2002
• Issued: 08/01/2006
• Est. Priority Date: 08/10/2001
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Lee, Gill Yong, Edelstein, Daniel C., Conti, Richard A.
• Primary Examiner(s): LE, DUNG ANH
• Application Number:
  US10/299,357
• Publication Number:
  US 20030068853A1
• Time in Patent Office: 1,352 Days
• Field of Search: 438/676, 438/623, 438/627, 438/687, 438/780
• US Class Current: 438/778
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: H01L 21/02112 characterised by the material of the layer
• CPC Class Codes: H01L 21/02129 the material being boron or phosphorus doped silicon oxides, e.g. BPSG, BSG or PSG
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• 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 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/3122 layers comprising polysiloxane compounds
• CPC Class Codes: H01L 21/31604 Deposition from a gas or vapour H01L21/31691, H01L21/31695 take precedence
• CPC Class Codes: H01L 21/31625 Deposition of boron or phosphorus doped silicon oxide, e.g. BSG, PSG, BPSG
• CPC Class Codes: H01L 21/31629 Deposition of halogen doped silicon oxide, e.g. fluorine doped silicon oxide
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 23/5329 Insulating materials
• 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 method is described for forming a low-k dielectric film, in particular, a pre-metal dielectric (PMD) on a semiconductor wafer which has good gap-filling characteristics. The method uses a thermal sub-atmospheric CVD process that includes a carbon-containing organometallic precusor such as TMCTS or OMCTS, an ozone-containing gas, and a source of dopants for gettering alkali elements and for lowering the reflow temperature of the dielectric while attaining the desired low-k and gap-filling properties of the dielectric film. Phosphorous is a preferred dopant for gettering alkali elements such as sodium. Additional dopants for lowering the reflow temperature include, but are not limited to boron, germanium, arsenic, fluorine or combinations thereof.

Claims

1. A method for depositing a dielectric film comprising the steps of:

providing a chemical vapor deposition (CVD) reaction chamber;

providing a semiconductor wafer within said reaction chamber, said wafer having features on a surface of said wafer, wherein said features are spaced to form at least one gap between said features;

providing a carbon-containing organometallic precursor;

providing an ozone-containing gas;

providing a dopant-containing gas;

reacting said precursor, said ozone-containing gas and said dopant-containing gas, to deposit a low-k film on said surface; and

reflowing said low-k film at a temperature less than about 725°

C. for about 20 minutes,

so that said low-k film fills said at least one gap.

2. The method of claim 1 wherein said gap has an aspect ratio greater than about 3.

3. The method of claim 1 wherein said low-k film has a dielectric constant of less than about 3.

4. The method of claim 1 wherein said CVD reaction chamber is a single wafer reactor.

5. The method of claim 1 further comprising the step of premixing said carbon-containing organometallic precursor, said ozone-containing gas and said dopant-containing gas prior to said step of reacting.

6. The method of claim 1 wherein said step of reacting comprises thermal sub-atmospheric pressure chemical vapor deposition.

7. The method of claim 1 wherein said carbon-containing precursor is elected from the group consisting of TMCTS and OMCTS.

8. The method of claim 1 wherein said step of providing a carbon-containing precursor comprises TMCTS flow between about 100 to about 10,000 mgm.

9. The method of claim 1 wherein said step of providing a carbon-containing precursor comprises TMCTS flow between about 100 to about 500 mgm.

10. The method of claim 1 wherein said step of providing an ozone-containing gas comprises flow of a mixture of oxygen and ozone from about 1000 to about 10,000 sccm.

11. The method of claim 10 wherein said ozone is between about 5 to 20 wt % of said mixture of oxygen and ozone.

12. The method of claim 10 wherein said ozone is about 15 wt % of said mixture of oxygen and ozone.

13. The method of claim 1 wherein said step of providing an ozone-containing gas comprises flow of a mixture of oxygen and ozone of about 5000 sccm.

14. The method of claim 13 wherein said ozone is between about 5 to 20 wt % of said mixture of oxygen and ozone.

15. The method of claim 13 wherein said ozone is about 15 wt % of said mixture of oxygen and ozone.

16. The method of claim 1 wherein said step of providing a dopant-containing gas comprises TEB flow and TEPO flow.

17. The method of claim 16 wherein said TEB flow is between about 100 to about 500 sccm and said TEPO flow is between about 10 to about 100 sccm.

18. The method of claim 1 wherein said dopant-containing gas includes a dopant selected from the group consisting of phosphorus, boron, germanium, arsenic, fluorine and a combination thereof.

19. The method of claim 1 wherein said dopant-containing gas include phosphorous and further includes a second dopant selected from the group consisting of boron, germanium, arsenic, fluorine and a combination thereof.

20. The method of claim 1 further comprising the step of pre-heating said reactor to a predetermined temperature following said step of providing a wafer.

21. The method of claim 20 wherein said predetermined temperature is between about 100-700°

C.

22. The method of claim 1 wherein said step of reacting said precursor further comprises achieving and maintaining a predetermined pressure.

23. The method of claim 22 wherein said predetermined pressure is between abou 50 to about 800 Torr.

24. The method of claim 22 wherein said predetermined pressure is between abou 200 to about 700 Torr.

25. A method for depositing a dielectric film comprising the steps of:

providing a chemical vapor deposition (CVD) reaction chamber;

providing a semiconductor wafer within said reaction chamber;

providing a semiconductor wafer within said reaction chamber, said wafer having features on a surface of said water, wherein said features are spaced to form at least one gap between said features;

preheating said reaction chamber to a predetermined temperature of about 500-600°

C.;

providing a carbon containing organometallic precursor selected from the group consisting of TMCTS and OMCTS;

providing an ozone-containing gas flowing at about 5000 sccm, wherein said ozone containing gas comprises oxygen and ozone, wherein said ozone has a concentration of about 15 wt %;

providing a dopant-containing gas including TEB flowing between about 100-500 sccm and TEPO flowing between about 10-100 sccm; and

reacting said precursor, said ozone-containing gas and said dopant-containing gas at a pressure between about 200-700 Torr to deposit a low-k film on said surface,

so that said low-k film substantially fills said at least one gap.

26. The method of claim 25 further comprising the step of premixing said carbon-containing organometallic precursor, said ozone-containing gas, and said dopant-containing gas prior to said step of reacting.

27. The method of claim 25 wherein said gap has an aspect ratio greater than about 3.

28. The method of claim 25 wherein said low-k film has a dielectric constant of less than about 3.

29. The method of claim 25 further comprising the step of reflowing said low-k film.

30. The method of claim 29 wherein said step of reflowing is performed at a temperature less than about 725°

C. for about 20 minutes.