Electron excitation atomic layer etch
Disclosed are apparatuses and methods for performing atomic layer etching. A method may include modifying one or more surface layers of material on the substrate and exposing the one or more modified surface layers on the substrate to an electron source thereby removing, without using a plasma, the one or more modified surface layers on the substrate. An apparatus may include a processing chamber, a process gas unit, an electron source, and a controller with instructions configured to cause the process gas unit to flow a first process gas to a substrate in a chamber interior, the first process gas is configured to modify one or more layers of material on the substrate, and to cause the electron source to generate electrons and expose the one or more modified surface layers on the substrate to the electrons, the one or more modified surface layers being removed, without using a plasma.
1. A method of processing a substrate, the method comprising:
reacting modifying molecules with one or more surface layers of material on the substrate to form one or more modified surface layers;
exposing the one or more modified surface layers on the substrate to an electron source thereby removing, without using a plasma, the one or more modified surface layers on the substrate; and
further comprising:
neutralizing, after the exposing, a charge on the substrate.
2. The method of claim 1 , wherein the exposing further comprises simultaneously exposing all of the one or more modified surface layers on the substrate to the electron source.
3. The method of claim 1 , wherein the exposing further comprises exposing a first section of the one or more modified surface layers to the electron source.
4. The method of claim 3 , wherein only the first section of the one or more modified surface layers is exposed to the electron source while a second section of the one or more modified surface layers is not exposed to the electron source.
5. The method of claim 3 , wherein the exposing further comprises exposing a second section of the one or more modified surface layers to the electron source after the exposing of the first section.
6. The method of claim 5 , wherein the exposing further comprises:
exposing the first section of the one or more modified surface layers to the electron source at a first beam energy level, and
exposing the second section of the one or more modified surface layers to the electron source at a second beam energy level.
7. The method of claim 5 , wherein the exposing further comprises:
exposing the first section of the one or more modified surface layers to the electron source for a first time period, and
exposing the second section of the one or more modified surface layers to the electron source for a second time period.
8. The method of claim 1 , wherein the exposing further comprises exposing the one or more modified surface layers on the substrate to the electron source at a beam energy level that is sufficient to cause anisotropic removal of the one or more modified surface layers from the substrate.
9. The method of claim 1 , wherein the exposing further comprises exposing the one or more modified surface layers on the substrate to the electron source at a beam energy level that is sufficient to cause isotropic removal of the one or more modified surface layers from the substrate.
10. The method of claim 1 , wherein the exposing further comprises exposing the one or more modified surface layers on the substrate to the electron source at a beam energy level that is sufficient to cause partial anisotropic removal of the one or more modified surface layers from the substrate.
11. The method of claim 1 , further comprising:
flowing, before or during the modifying, a first process gas onto the substrate, wherein the first process gas is configured to modify the one or more surface layers of material on the substrate.
12. The method of claim 1 , wherein the modifying further comprises exposing the one or more surface layers of material on the substrate to a plasma.
13. The method of claim 1 , further comprising:
repeating, while the substrate remains in a processing chamber, the modifying of one or more surface layers of material on the substrate and the exposing the one or more modified surface layers on the substrate to the electron source.
14. The method of claim 13 , further comprising:
purging the processing chamber between modifying and exposing operations.
15. The method of claim 1 , wherein the material has a surface binding energy of less than about 4.5 electron volts (eV).
16. The method of claim 15 , wherein the material comprises one or more of: germanium, gold, and silver.
17. The method of claim 1 , wherein substrate temperature during the modifying and the exposing is substantially the same.
18. The method of claim 1 , wherein the modifying molecules comprise diatomic chlorine or carbon monoxide.
19. A method of processing a substrate, the method comprising:
reacting modifying molecules with one or more surface layers of material on the substrate to form one or more modified surface layers;
converting, after the reacting, the one or more modified surface layers on the substrate to one or more converted layers;
exposing the one or more converted layers on the substrate to an electron source thereby removing, without using a plasma, the one or more converted surface layers on the substrate; and
further comprising:
neutralizing, after the exposing, a charge on the substrate.
20. The method of claim 19 , wherein the converting further comprises flowing a second process gas onto the substrate, wherein the second process gas is configured to convert the one or more modified surface layers on the substrate to the one or more converted layers.
21. The method of claim 19 , wherein the modifying further comprises exposing the one or more surface layers of material on the substrate to a plasma.
22. The method of claim 19 , wherein the converting further comprises exposing the one or more surface layers of material on the substrate to a plasma.
23. The method of claim 19 , wherein the modifying molecules comprise diatomic chlorine or carbon monoxide.