Hardmask for high aspect ratio dielectric etch at cryo and elevated temperatures

Patent metadata

Field	Value
Publication number	US-2025308894-A1
Application number	US-202318863211-A
Country	US
Kind code	A1
Filing date	May 16, 2023
Priority date	May 19, 2022
Publication date	Oct 2, 2025
Grant date	—

Abstract

Various embodiments herein relate to methods, apparatus, and systems for etching high aspect ratio features in dielectric material. The dielectric material is etched using a multi-layer or graded hardmask having at least two different compositions. Different etching regimes are used when the different portions of the hardmask are exposed. For example, a feature may be etched to a first depth at a first temperature while an upper portion of the hardmask is exposed, and then etched to a final depth at a second temperature while a lower portion of the hardmask is exposed, the second temperature being higher than the first temperature.

First claim

What is claimed is:

1 . A method of etching a feature into a substrate, the method comprising:
receiving a substrate in a process chamber, the substrate comprising:
dielectric material, and
a hardmask comprising an upper portion and a lower portion, the upper portion comprising carbon, and the lower portion comprising at least one material selected from the group consisting of: doped carbon, silicon, a metal, a metal-containing material, and combinations thereof,
wherein the upper portion and lower portion of the hardmask have different compositions,
wherein the hardmask is patterned to define a location where the feature will be etched in the dielectric material, and
wherein the hardmask is positioned over the dielectric material;
etching the feature to a first depth into the substrate while the substrate is at a first temperature and while the upper portion of the hardmask is exposed; and etching the feature to a final depth while the substrate is at a second temperature and while the lower portion of the hardmask is exposed, wherein the second temperature is higher than the first temperature.

2 . The method of claim 1 , wherein the first temperature is between about −100° C. and about 0° C., and the second temperature is between about 0° C. and about 100° C.

3 . The method of claim 2 , wherein the first temperature is between about −60° C. and about −20° C., and the second temperature is between about 20° C. and about 60° C.

4 . The method of claim 1 , wherein the lower portion of the hardmask comprises one or more metal selected from the group consisting of aluminum, boron, chromium, cobalt, hafnium, molybdenum, niobium, ruthenium, tantalum, titanium, tungsten, vanadium, zirconium, and combinations thereof.

5 . The method of claim 4 , wherein the lower portion of the hardmask has a composition that is at least about 5 at % metal.

6 . The method of claim 1 , further comprising exposing the substrate to an oxygen-containing plasma to ash away any remaining upper portion of the hardmask after etching the feature to the first depth into the substrate and before etching the feature to the final depth.

7 . The method of claim 1 , further comprising depositing a liner on sidewalls of the feature after etching the feature to the first depth into the substrate and before etching the feature to the final depth.

8 . The method of claim 1 , further comprising depositing additional mask material on the hardmask after etching the feature to the first depth into the substrate and before etching the feature to the final depth.

9 . The method of claim 1 , wherein the upper portion and lower portion of the hardmask are distinct layers.

10 . The method of claim 1 , wherein the hardmask has a graded composition, such that a composition of the upper portion of the hardmask is graded into a composition of the lower portion of the hardmask.

11 . An apparatus for etching a substrate, the apparatus comprising:
a process chamber; a substrate support configured to support the substrate in the process chamber; an inlet to the process chamber for introducing one or more reactants to the process chamber; an outlet to the process chamber for removing materials from the process chamber; a controller comprising a memory and a processor, wherein the controller is configured to cause:
receiving the substrate in the process chamber, the substrate comprising:
dielectric material, and
a hardmask comprising an upper portion and a lower portion, the upper portion comprising carbon, and the lower portion comprising at least one material selected from the group consisting of doped carbon, silicon, a metal, a metal-containing material, and combinations thereof,
wherein the upper portion and lower portion of the hardmask have different compositions,
wherein the hardmask is patterned to define a location where the feature will be etched in the dielectric material, and
wherein the hardmask is positioned over the dielectric material;

etching the feature to a first depth into the substrate while the substrate is at a first temperature and while the upper portion of the hardmask is exposed; and
etching the feature to a final depth while the substrate is at a second temperature and while the lower portion of the hardmask is exposed, wherein the second temperature is higher than the first temperature.

12 . The apparatus of claim 11 , wherein the first temperature is between about −100° C. and about 0° C., and the second temperature is between about 0° C. and about 100° C.

13 . The apparatus of claim 12 , wherein the first temperature is between about −60° C. and about −20° C., and the second temperature is between about 20° C. and about 60° C.

14 . The apparatus of claim 11 , wherein the lower portion of the hardmask comprises one or more metal selected from the group consisting of aluminum, boron, chromium, cobalt, hafnium, molybdenum, niobium, ruthenium, tantalum, titanium, tungsten, vanadium, zirconium, and combinations thereof.

15 . The apparatus of claim 14 , wherein the lower portion of the hardmask has a composition that is at least about 5 at % metal.

16 . The apparatus of claim 11 , wherein the controller is further configured to cause exposing the substrate to an oxygen-containing plasma to ash away any remaining upper portion of the hardmask after etching the feature to the first depth into the substrate and before etching the feature to the final depth.

17 . The apparatus of claim 11 , wherein the controller is further configured to cause depositing a liner on sidewalls of the feature after etching the feature to the first depth into the substrate and before etching the feature to the final depth.

18 . The apparatus of claim 11 , wherein the controller is further configured to cause depositing additional mask material on the hardmask after etching the feature to the first depth into the substrate and before etching the feature to the final depth.

19 . The apparatus of claim 11 , wherein the upper portion and lower portion of the hardmask are distinct layers.

20 . The apparatus of claim 11 , wherein the hardmask has a graded composition, such that a composition of the upper portion of the hardmask is graded into a composition of the lower portion of the hardmask.

Assignees

• Lam Res Corp

Inventors

• Lill Thorsten Bernd
• Puthenkovilakam Ragesh
• Reddy Kapu Sirish
• Hoang John
• Shen Meihua
• Wu Hui-Jung
• Bhadauriya Sonal
• Chi Hao
• Routzahn Aaron Lynn
• Yu Anthony Sky
• Roberts Francis Sloan

Classifications

• H10P76/4085

  characterised by the processes involved to create the masks · CPC title

• H10P50/283

  by chemical means · CPC title

• H10P50/73 Primary

  using masks for insulating materials · CPC title

• H10W20/081

  by forming openings in the dielectric parts · CPC title

• H10W20/033

  in openings in dielectrics · CPC title