METHOD OF SIDEWALL IMAGE TRANSFER

• US 20170345671A1
• Filed: 05/26/2017
• Published: 11/30/2017
• Est. Priority Date: 05/29/2016
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Ranjan, Alok, Sherpa, Sonam D.
• Granted Patent: US 10,373,828 B2
• Time in Patent Office: Days
• 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 21/02238 silicon in uncombined form, i.e. pure silicon
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0337 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/32137 of silicon-containing layers

Abstract

According to one embodiment, a substrate processing method includes providing a substrate containing Si raised features, depositing a conformal film on the Si raised features, and performing a spacer etch process that removes horizontal portions of the conformal film while substantially leaving vertical portions of the conformal film to form sidewall spacers on the Si raised features, the performing including a) exposing the substrate to a plasma-excited first process gas consisting of H₂ gas and optionally an inert gas, and b) exposing the substrate to a plasma-excited second process gas containing i) NF₃, O₂, H₂, and Ar, ii) NF₃, O₂, and H₂, iii) NF₃ and O₂, NF₃, O₂, and Ar, iv) NF₃ and H₂, or v) NF₃, H₂, and Ar. The method further includes removing the Si raised features while maintaining the sidewall spacers on the substrate. The removing may be performed using steps a) and b).

Claims

1. A substrate processing method, the method comprising:

providing a substrate containing silicon (Si) raised features;

depositing a conformal film on the Si raised features;

performing a spacer etch process that removes horizontal portions of the conformal film while substantially leaving vertical portions of the conformal film to form sidewall spacers on the Si raised features, the performing including

a) exposing the substrate to a plasma-excited first process gas consisting of H₂ gas and optionally an inert gas, and

b) exposing the substrate to a plasma-excited second process gas containing i) NF₃, O₂, H₂, and Ar, ii) NF₃, O₂, and H₂, iii) NF₃ and O₂, NF₃, O₂, and Ar, iv) NF₃ and H₂, or v) NF₃, H₂, and Ar; and

removing the Si raised features while maintaining the sidewall spacers on the substrate, the removing including

c) exposing the substrate to a plasma-excited third process gas consisting of H₂ gas and optionally an inert gas, and

d) exposing the substrate to a plasma-excited fourth process gas containing i) NF₃, O₂, H₂, and Ar, ii) NF₃, O₂, and H₂, iii) NF₃ and O₂, iv) NF₃, O₂, and Ar, v) NF₃ and H₂, or vi) NF₃, H₂, and Ar.

2. The method of claim 1, wherein the first and third process gases consist of H₂ and Ar.

3. The method of claim 1, wherein the second and fourth process gases consist of NF₃, ^O₂, H₂, and Ar.

4. The method of claim 1, wherein the Si raised features consist of elemental Si.

5. The method of claim 4, wherein the elemental Si includes polycrystalline Si (poly-Si) or amorphous Si (a-Si).

6. The method of claim 1, wherein the second material is selected from the group consisting of SiN, SiO₂, and a combination thereof

7. The method of claim 1, wherein the plasma-excited process gases are formed using a capacitively coupled plasma source containing an upper plate electrode, and a lower plate electrode supporting the substrate.

8. The method of claim 1, wherein the plasma-excited process gases are formed using a remote plasma source that creates a high radical to ion flux ratio.

9. The method of claim 1, further repeating steps a) and b), and steps c) and d), at least once.

10. A substrate processing method, the method comprising:

providing a substrate containing Si raised features;

depositing a conformal film on the Si raised features;

performing a plasma process that modifies horizontal portions of the conformal film while substantially leaving vertical portions of the conformal film unmodified, the performing including

a) exposing the substrate to a plasma-excited first process gas consisting of H₂ gas and optionally an inert gas, and

b) exposing the substrate to a plasma-excited second process gas containing i) NF₃, O₂, H₂, and Ar, ii) NF₃, O₂, and H₂, iii) NF₃ and O₂, NF₃, O₂, and Ar, iv) NF₃ and H₂, or v) NF₃, H₂, and Ar; and

removing the modified horizontal portions of the conformal film and the Si raised features, the removing including

c) exposing the substrate to a plasma-excited third process gas consisting of H₂ gas and optionally an inert gas, and

d) exposing the substrate to a plasma-excited fourth process gas containing i) NF₃, O₂, H₂, and Ar, ii) NF₃, O₂, and H₂, iii) NF₃ and O₂, iv) NF₃, O₂, and Ar, v) NF₃ and H₂, or vi) NF₃, H₂, and Ar.

11. The method of claim 10, wherein the first and third process gases consist of H₂ and Ar.

12. The method of claim 10, wherein the second and fourth process gases consist of NF₃, O₂, H₂, and Ar.

13. The method of claim 10, wherein the Si raised features include polycrystalline Si (poly-Si) or amorphous Si (a-Si).

14. The method of claim 10, wherein the second material is selected from the group consisting of SiN, SiO₂, and a combination thereof

15. The method of claim 10, wherein the plasma-excited process gases are formed using a capacitively coupled plasma source containing an upper plate electrode, and a lower plate electrode supporting the substrate.

16. The method of claim 10, wherein the plasma-excited process gases are formed using a remote plasma source that creates a high radical to ion flux ratio.

17. The method of claim 10, further including repeating steps a) and b), and steps c) and d), at least once.

18. A substrate processing method, the method comprising:

providing a substrate containing SiN sidewall spacers on Si raised features; and

removing the Si raised features while maintaining the SiN sidewall spacers on the substrate, the removing including

exposing the substrate to a first plasma-excited process gas consisting of H₂ gas and optionally an inert gas, and

exposing the substrate to a second plasma-excited process gas containing i) NF₃, O₂, H₂, and Ar, ii) NF₃, O₂, and H₂, iii) NF₃ and O₂, iv) NF₃, O₂, and Ar, v) NF₃ and H₂, or vi) NF₃, H₂, and Ar.

19. The method of claim 19, wherein the first process gas consists of H₂ and Ar, and the second process gas consists of NF₃, O₂, H₂, and Ar.

20. The method of claim 19, further including repeating the exposing steps at least once.