Methods and systems for forming at least one dielectric layer

• US 7,871,926 B2
• Filed: 10/22/2007
• Issued: 01/18/2011
• Est. Priority Date: 10/22/2007
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Yang, Haichun, Xia, Li-Qun, Kao, Chien-Teh, Lu, Xinliang, Chang, Mei, Nguyen, Victor, Balseanu, Mihaela, Witty, Derek R., M'Saad, Hichem
• Primary Examiner(s): TRINH, MICHAEL MANH
• Application Number:
  US11/876,649
• Publication Number:
  US 20090104764A1
• Time in Patent Office: 1,184 Days
• Field of Search: 438/761, 438/763, 438/624, 438/758, 257/E21.249, 257/E21.293
• US Class Current: 438/624
• 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 21/0214 the material being a silicon oxynitride, e.g. SiON or SiON:H
• 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 21/02326 into a nitride layer, e.g. changing SiN to SiON
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/3143 composed of alternated layers or of mixtures of nitrides and oxides or of oxinitrides, e.g. formation of oxinitride by oxidation of nitride layers
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 21/76829 characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers
• CPC Class Codes: H01L 21/76832 Multiple layers
• 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 for forming a structure includes forming at least one feature across a surface of a substrate. A nitrogen-containing dielectric layer is formed over the at least one feature. A first portion of the nitrogen-containing layer on at least one sidewall of the at least one feature is removed at a first rate and a second portion of the nitrogen-containing layer over the substrate adjacent to a bottom region of the at least one feature is removed at a second rate. The first rate is greater than the second rate. A dielectric layer is formed over the nitrogen-containing dielectric layer.

Claims

1. A method for forming a structure, comprising:

forming at least one feature across a surface of a substrate;

forming a silicon carbon nitride layer over the at least one feature;

substantially oxidizing the silicon carbon nitride layer into a silicon oxynitride layer;

removing a first portion of the silicon oxynitride layer on at least one sidewall of the at least one feature at a first rate and a second portion of the silicon oxynitride layer over the substrate adjacent to a bottom region of the at least one feature at a second rate, the first rate being greater than the second rate; and

forming a dielectric layer over the silicon oxynitride layer.

2. The method of claim 1, wherein forming the at least one feature comprises forming at least one transistor gate.

3. The method of claim 2 further comprising:

forming at least one contact region within the substrate and adjacent to the at least one transistor gate; and

forming at least one dielectric spacer on at least one sidewall of the at least one transistor gate.

4. The method of claim 1, wherein removing the first portion and the second portion of the silicon oxynitride layer further comprises removing a third portion of the silicon oxynitride layer over the at least one feature at a third rate, and a ratio of the third rate to the second rate is about 2:

1 or more.

5. The method of claim 1, wherein removing the portions of the silicon oxynitride layer comprises:

generating a fluorine-containing plasma;

interacting the fluorine-containing plasma with the first portion and the second portion of the silicon oxynitride layer to generate a byproduct; and

thermally treating the byproduct to remove the portions of the silicon oxynitride layer.

6. The method of claim 5, wherein generating the fluorine-containing plasma uses a precursor selected from the group consisting of trifluoride (NF₃), silicon tetrafluoride (SiF₄), tetrafluoromethane (CF₄), fluoromethane (CH₃F), difluoromethane (CH₂F₂), trifluoromethane (CHF₃), octafluoropropane (C₃F₈) and hexafluoroethane (C₂F₆).

7. The method of claim 5, wherein interacting the fluorine-containing plasma with the portions of the silicon oxynitride layer comprises disposing the substrate on a pedestal having a temperature between about −

100°

C. and about 1,000°

C.

8. The method of claim 5, wherein thermally treating the byproduct comprises sublimating the byproduct.

9. The method of claim 5, wherein thermally treating the byproduct has a process temperature between about −

50°

C. and about 1,000°

C.

10. The method of claim 5 further comprising lifting the substrate approaching a showerhead.

11. A method for forming a transistor, comprising:

forming at least one transistor gate over a substrate;

forming at least one dielectric spacer on sidewalls of the at least one transistor gate;

forming at least one contact region within the substrate and adiacent to the transistor gate;

forming a silicon carbon nitride layer over the at least one transistor gate;

substantially oxidizing the silicon carbon nitride layer into a silicon oxynitride layer;

removing a first portion of the silicon oxynitride layer on at least one sidewall of the at least one transistor gate at a first rate and a second portion of the silicon oxynitride layer over the substrate adiacent to a bottom region of the at least one transistor gate at a second rate, the first rate being greater than the second rate; and

forming a dielectric layer over the silicon oxynitride layer.

12. The method of claim 11, wherein removing the first portion and the second portion of the silicon oxynitride layer comprises:

generating a fluorine-containing plasma;

interacting the fluorine-containing plasma with the first portion and the second portion of the silicon oxynitride layer to generate a byproduct; and

thermally treating the byproduct to remove the first portion and the second portion of the silicon oxynitride layer.

13. The method of claim 12, wherein generating the fluorine-containing plasma uses a precursor selected from the group consisting of trifluoride (NF₃), silicon tetrafluoride (SiF₄), tetrafluoromethane (CF₄), fluoromethane (CH₃F), difluoromethane (CH₂F₂), trifluoromethane (CHF₃), octafluoropropane (C₃F₈) and hexafluoroethane (C₂F₆).

14. The method of claim 12, wherein interacting the fluorine-containing plasma with the portions of the silicon oxynitride layer comprises disposing the substrate on a pedestal having a temperature between about −

100°

C. and about 1,000°

C.

15. The method of claim 12, wherein thermally treating the byproduct comprises sublimating the byproduct.

16. The method of claim 12, wherein thermally treating the byproduct has a process temperature between about −

50°

C. and about 1,000°

C.

17. The method of claim 12 further comprising lifting the substrate approaching a showerhead.