Conformal layers by radical-component CVD

• US 8,563,445 B2
• Filed: 02/10/2011
• Issued: 10/22/2013
• Est. Priority Date: 03/05/2010
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Liang, Jingmei, Chen, Xiaolin, Li, DongQing, Ingle, Nitin K.
• Primary Examiner(s): Garber, Charles
• Assistant Examiner(s): Patel, Reema
• Application Number:
  US13/024,487
• Publication Number:
  US 20110217851A1
• Time in Patent Office: 985 Days
• Field of Search: 438/792, 438/791, 438/786, 438/778
• US Class Current: 438/792
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/452 by activating reactive gas streams before their introduction into the reaction chamber, e.g. by ionisation or addition of reactive species
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• 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 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/02326 into a nitride layer, e.g. changing SiN to SiON
• CPC Class Codes: H01L 21/76837 Filling up the space between adjacent conductive structures; Gap-filling properties of dielectrics

Abstract

Methods, materials, and systems are described for forming conformal dielectric layers containing silicon and nitrogen (e.g., a silicon-nitrogen-hydrogen (Si—N—H) film) from a carbon-free silicon-and-nitrogen precursor and radical-nitrogen precursor. The carbon-free silicon-and-nitrogen precursor is predominantly excited by contact with the radical-nitrogen precursor. Because the silicon-and-nitrogen film is formed without carbon, the conversion of the film into hardened silicon oxide is done with less pore formation and less volume shrinkage. The deposited silicon-and-nitrogen-containing film may be wholly or partially converted to silicon oxide which allows the optical properties of the conformal dielectric layer to be selectable. The deposition of a thin silicon-and-nitrogen-containing film may be performed at low temperature to form a liner layer in a substrate trench. The low temperature liner layer has been found to improve the wetting properties and allows flowable films to more completely fill the trench.

Claims

1. A method of forming a conformal silicon-and-nitrogen-containing layer on a patterned substrate in a substrate processing region in a substrate processing chamber, the method comprising:

mixing a carbon-free silicon-and-nitrogen-containing precursor with a radical-nitrogen precursor, wherein the carbon-free silicon-and-nitrogen-containing precursor is predominantly excited by contact with the radical-nitrogen precursor; and

depositing a conformal silicon-and-nitrogen-containing layer having a conformal layer thickness on the patterned substrate, wherein the patterned substrate comprises a substrate gap.

2. The method of claim 1 wherein a conformal deposition pressure in the substrate processing region during deposition of the conformal silicon-and-nitrogen-containing film is below or about 200 mTorr.

3. The method of claim 1 wherein a conformal deposition temperature of the substrate during deposition of the conformal silicon-and-nitrogen-containing film is below or about 200°

C.

4. The method of claim 1 wherein the conformal layer thickness is below or about 20 nm.

5. The method of claim 1 further comprising converting the silicon-and-nitrogen containing layer to a silicon-and-oxygen-containing layer by exposing the silicon-and-nitrogen-containing layer to ozone.

6. The method of claim 1, wherein the carbon-free silicon-and-nitrogen containing precursor comprises a silyl-amine.

7. The method of claim 6 wherein the silyl-amine comprises N(SiH₃)₃.

8. The method of claim 1 wherein the radical-nitrogen precursor is generated from a nitrogen-and-hydrogen containing gas using a plasma before being mixed with the carbon-free silicon-and-nitrogen containing precursor.

9. The method of claim 8 wherein the nitrogen-and-hydrogen containing gas comprises a gas selected from the group consisting of ammonia, N₂ and H₂.

10. The method of claim 1 wherein the conformal silicon-and-nitrogen containing layer comprises a carbon-free Si—

N—

H layer.

11. The method of claim 1 wherein the conformal silicon-and-nitrogen containing layer is converted to a silicon oxide layer by exposing the silicon-and-nitrogen containing layer to an oxygen-containing atmosphere.

12. The method of claim 11 wherein the oxygen-containing atmosphere comprises one or more gases selected from the group consisting of oxygen, ozone, and steam.

13. A method of forming a silicon-containing layer with reduced volume shrinkage, the method comprising:

transferring a substrate containing a gap;

mixing a carbon-free silicon-and-nitrogen-containing precursor with a radical-nitrogen precursor, wherein the carbon-free silicon-and-nitrogen-containing precursor is predominantly excited by contact with the radical-nitrogen precursor;

depositing a conformal silicon-and-nitrogen-containing layer on the substrate, wherein the conformal silicon-and-nitrogen-containing layer has a conformality and is formed from the mixing of the carbon-free silicon-and-nitrogen-containing precursor with the radical-nitrogen precursor; and

depositing a flowable silicon-and-nitrogen-containing layer over the conformal silicon-and-nitrogen-containing layer, wherein the silicon-containing layer comprises both the conformal silicon-and-nitrogen-containing layer and the flowable silicon-and-nitrogen-containing layer.

14. The method of claim 13 further comprising heating the silicon-containing layer in an oxygen-containing atmosphere to increase the oxygen content, wherein the silicon-containing layer retains a volume of about 85% or more of the carbon-free silicon-and-nitrogen containing layer deposited in the gap.

15. The method of claim 13 wherein the conformality of the conformal silicon-and-nitrogen-containing layer is greater than or about 80%.

16. The method of claim 13 wherein the conformal silicon-and-nitrogen containing layer is deposited on the substrate by the reaction of a silicon-and-nitrogen-containing precursor with a radical-nitrogen precursor, wherein the radical-nitrogen precursor provides the dominant excitation to the silicon-and-nitrogen precursor.

17. The method of claim 16 wherein the silicon-and-nitrogen-containing precursor comprises N(SiH₃)₃ and the radical-nitrogen precursor is formed from plasma-activated NH₃.

18. The method of claim 14 wherein the oxygen-containing atmosphere comprises at least one of O₂, O₃, or H₂O.

19. The method of claim 13 wherein the silicon-containing layer in the gap is substantially void-free.

20. The method of claim 16 wherein the silicon-and-nitrogen containing layer comprises a Si—

N—

H layer.

21. The method of claim 13 wherein the conformal silicon-and-nitrogen-containing layer comprises a Si—

N—

H layer.

22. The method of claim 13 wherein the substrate gap has a width of about 50 nm or less.