Selective attachment to enhance SiO2:SiNx etch selectivity

Patent metadata

Field	Value
Publication number	US-12479004-B2
Application number	US-202017754020-A
Country	US
Kind code	B2
Filing date	Oct 15, 2020
Priority date	Oct 18, 2019
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

Methods and apparatuses for selectively etching silicon-and-oxygen-containing material relative to silicon-and-nitrogen-containing material by selectively forming a carbon-containing self-assembled monolayer on a silicon-and-nitrogen-containing material relative to a silicon-and-oxygen-containing material are provided herein. Methods are also applicable to selectively etching silicon-and-nitrogen-containing material relative to silicon-and-oxygen-containing material.

First claim

What is claimed is:

1 . A method for processing substrates, the method comprising:
providing a substrate having a silicon-and-nitrogen-containing surface and a silicon-and-oxygen-containing surface; exposing the substrate to a carbon-containing self-assembled monolayer precursor in a non-plasma environment such that the carbon-containing self-assembled monolayer precursor selectively attaches to the silicon-and-nitrogen-containing surface to form a protected surface and a non-functionalized surface; and exposing the substrate comprising the protected surface to a process for etching the non-functionalized surface.

2 . The method of claim 1 , wherein the protected surface comprises a protected silicon-and-nitrogen-containing surface, and wherein the non-functionalized surface comprises a non-functionalized silicon-and-oxygen-containing surface.

3 . The method of claim 1 , wherein the carbon-containing self-assembled monolayer precursor comprises a head group having greater reactivity with the silicon-and-nitrogen-containing surface relative to the silicon-and-oxygen-containing surface.

4 . The method of claim 1 , wherein the carbon-containing self-assembled monolayer precursor comprises:
R 1 —C(O)—R 2 or R 1 —NCS,
wherein R 1 comprises an organic moiety, and wherein R 2 is hydrogen (H) or an organic moiety.

5 . The method of claim 4 , wherein each of R 1 and/or R 2 is or comprises, independently, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted cycloaliphatic, optionally substituted cycloheteroaliphatic, or optionally substituted aromatic.

6 . The method of claim 1 , wherein the carbon-containing self-assembled monolayer precursor is selected from the group consisting of an aldehyde, an isothiocyanate, benzaldehyde, a derivative of benzaldehyde with one or more fluorine atoms substituted for hydrogen atoms, 1-hexanal, 3,5,5-trimethylhexanal phenyl isothiocyanate, and hexyl isothiocyanate.

7 . The method of claim 1 , further comprising repeating exposing the substrate to the carbon-containing self-assembled monolayer precursor after the exposing the substrate to the process for etching the non-functionalized surface.

8 . The method of claim 1 , wherein the exposing the substrate to the process for etching the non-functionalized surface comprises performing atomic layer etching and/or continuous etching.

9 . The method of claim 1 , wherein the exposing the substrate to the process for etching the non-functionalized surface comprises:
exposing the substrate to a plasma reactive species generated from a fluorocarbon plasma to form a reactive layer; and exposing the substrate to an activation plasma to remove the reactive layer.

10 . The method of claim 9 , further comprising repeating exposing the substrate to the plasma reactive species and exposing the substrate to the activation plasma in cycles.

11 . The method of claim 9 , wherein the fluorocarbon plasma is generated from a fluorocarbon selected from the group consisting of C 4 F 6 , C 4 F 8 , a perfluorocarbon, a fluorohydrocarbon, and combinations thereof; and/or wherein the activation plasma comprises argon, helium, or an inert gas.

12 . The method of claim 9 , wherein the exposing of the substrate to the plasma reactive species and exposing the substrate to the activation plasma are performed in temporally separated alternating pulses.

13 . The method of claim 1 , wherein the exposing the substrate to the carbon-containing self-assembled monolayer precursor is performed at a wafer temperature between about −40° C. and about 550° C.; and/or performed with a dose between about 0.1 ML and about 500 ML.

14 . The method of claim 1 , wherein the exposing the substrate to the carbon-containing self-assembled monolayer precursor and the exposing the substrate to the process are performed without breaking vacuum.

15 . The method of claim 14 , wherein the process comprises introducing a fluorocarbon plasma.

16 . The method of claim 1 , further comprising prior to exposing the substrate to the carbon-containing self-assembled monolayer precursor, exposing the substrate to a treatment gas in a plasma environment.

17 . The method of claim 16 , wherein the treatment gas is selected from the group consisting of argon, nitrogen, hydrogen, helium, and combinations thereof.

18 . The method of claim 16 , wherein the exposing the substrate to the treatment gas in the plasma environment comprises applying an RF bias.

19 . The method of claim 1 , wherein the protected surface prevents activation of the non-functionalized surface when exposed to argon plasma.

20 . The method of claim 1 , wherein the silicon-and-nitrogen-containing surface comprises material selected from the group consisting of silicon oxynitride, silicon carbonitride, hydrogen-terminated silicon nitride, dopant versions thereof, and combinations thereof.

21 . The method of claim 1 , wherein the silicon-and-nitrogen-containing surface comprises —NHx groups.

22 . The method of claim 1 , wherein the silicon-and-oxygen-containing surface comprises a low-k dielectric.

23 . The method of claim 1 , wherein the silicon-and-nitrogen-containing surface comprises a first sidewall surface, the silicon-and-oxygen-containing surface comprises a second sidewall surface, and the protected surface comprises a protected sidewall surface; and wherein the process for etching comprises vertical etching through a feature comprising the first sidewall surface and the second sidewall surface.

24 . The method of claim 23 , wherein the feature has an aspect ratio of at least about 20:1.

Assignees

• Lam Res Corp

Inventors

• Hudson Eric A
• Wang Chia-Chun
• Agarwal Sumit
• Gasvoda Ryan James

Classifications

• H10W20/069

  by forming self-aligned vias or self-aligned contact plugs · CPC title

• H10P95/00

  Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass · CPC title

• H10P50/283 Primary

  by chemical means · CPC title

• B05D2203/30

  Other inorganic substrates, e.g. ceramics, silicon · CPC title

• B05D3/145

  After-treatment · CPC title