Methods to reduce UNCD film roughness

Patent metadata

Field	Value
Publication number	US-12327733-B2
Application number	US-202217671938-A
Country	US
Kind code	B2
Filing date	Feb 15, 2022
Priority date	Feb 15, 2022
Publication date	Jun 10, 2025
Grant date	Jun 10, 2025

Abstract

Hard masks and methods of forming hard masks are described. The hard mask has an average roughness less than 10 nm and a modulus greater than or equal to 400 GPa. The method comprises exposing a substrate to a deposition gas comprising a dopant gas or a precursor (solid (e.g. Alkylborane compounds) or liquid (e.g. Borazine)), a carbon gas and argon at a temperature less than or equal to 550 C, and igniting a plasma from the deposition gas to form an ultrananocrystalline diamond film having an average roughness less than 10 nm and a modulus greater than or equal to 400 GPa.

First claim

What is claimed is:

1. A method of forming a patterned hard mask, the method comprising:
exposing a semiconductor wafer to a deposition gas comprising a boron dopant gas comprising 5% to 20% diborane in H 2 on a molar basis, a carbon gas comprising one or more of methane or carbon dioxide in H 2 and 50% to 90% argon on a molar basis at a temperature less than or equal to 550° C.;
igniting a pulsed microwave plasma from the deposition gas to form a boron doped ultrananocrystalline diamond film having an average roughness less in a range of from 0.1 nm to 5 nm and a modulus in a range of from 250 to 400 GPa; wherein there is a gas pressure during forming the boron doped ultrananocrystalline diamond film in a range of 0.2 Torr to 2 Torr and a plasma power in a range of from 3 kW to 10 KW; and
patterning the hard mask to form the patterned hard mask.

2. The method of claim 1 , wherein the dopant gas further comprises one or more of a nitrogen dopant, a sulfur dopant species and a phosphorous dopant species.

3. The method of claim 1 , wherein the deposition gas comprises greater than or equal to 60% argon.

4. The method of claim 1 , wherein the pulsed microwave plasma is pulsed at a duty cycle in a range of 25% to 75%.

5. The method of claim 4 , wherein the pulsed microwave plasma is pulsed at a 50% duty cycle.

6. The method of claim 5 , wherein the film has a modulus greater than 350 GPa.

7. The method of claim 6 , wherein the boron doped ultrananocrystalline diamond has a thickness in the range of 300 nm to 500 nm.

8. The method of claim 7 , wherein the patterned hard mask is patterned by etching and subsequently withstands a reactive plasma etching during formation of a 3D NAND device.

9. The method of claim 1 , wherein the temperature is less than or equal to 500° C.

10. The method of claim 1 , wherein a microwave plasma source used to generate the pulsed microwave plasma is spaced at a distance from the semiconductor wafer in a range of from 5 cm to 8 cm.

11. A method of forming a patterned hard mask comprising:
forming a hard mask on a semiconductor wafer comprising:
exposing the semiconductor wafer to a deposition gas comprising a boron dopant gas comprising 5% to 20% diborane in H 2 on a molar basis a carbon gas comprising methane and carbon dioxide in H 2 , and in the range of 10% to 90% argon on a molar basis at a temperature less than or equal to 550° C., and
igniting a pulsed microwave plasma from the deposition gas to form a boron doped ultrananocrystalline diamond film having an average roughness in a range of from 0.1 nm to 5 nm and a modulus greater than or equal to 400 GPa, the pulsed microwave plasma having a 50% duty cycle; wherein there is a gas pressure during forming the boron doped ultrananocrystalline diamond film in a range of 0.2 Torr to 2 Torr and a plasma power in a range of from 3 kW to 10 kW; and

patterning the hard mask to form a patterned hard mask on the semiconductor wafer.

12. The method of claim 11 , wherein the deposition gas comprises greater than or equal to 50% argon.

13. The method of claim 12 , wherein patterning the hard mask comprises etching the hard mask.

14. The method of claim 13 , wherein the temperature is less than 500° C.

15. The method of claim 13 , wherein the film comprises a hard mask with a thickness in the range of 300 nm to 500 nm.

16. The method of claim 15 , wherein the patterned hard mask is patterned by etching and subsequently withstands a reactive plasma etching during formation of a 3D NAND device.

17. The method of claim 11 , wherein a microwave plasma source used to generate the pulsed microwave plasma is spaced at a distance from the semiconductor wafer in a range of from 5 cm to 8 cm.

Assignees

• Applied Materials Inc
• Nat Univ Singapore

Inventors

• Sahmuganathan Vicknesh
• Venkatasubramanian Eswaranand
• Gu Jiteng
• Loh Kian Ping
• Mallick Abhijit Basu
• Sudijono John

Classifications

• H10P14/668

  the materials being characterised by the deposition precursor materials · CPC title

• H10P14/6902

  composed of carbon, e.g. alpha-C, diamond or hydrogen doped carbon · CPC title

• H10P14/6336 Primary

  in the presence of a plasma [PECVD] · CPC title

• H10P50/73 Primary

  using masks for insulating materials · CPC title

• H10P76/405

  characterised by their composition, e.g. multilayer masks · CPC title