Two-step fluorine radical etch of hafnium oxide
In one implementation, a method of removing a metal-containing layer is provided. The method comprises generating a plasma from a fluorine-containing gas. The plasma comprises fluorine radicals and fluorine ions. The fluorine ions are removed from the plasma to provide a reactive gas having a higher concentration of fluorine radicals than fluorine ions. A substrate comprising a metal-containing layer is exposed to the reactive gas. The reactive gas dopes at least a portion of the metal-containing layer to form a metal-containing layer doped with fluorine radicals. The metal-containing layer doped with fluorine radicals is exposed to a nitrogen and hydrogen containing gas mixture and the reactive gas to remove at least a portion of the metal-containing layer doped with fluorine radicals.
1. A method comprising:
flowing a fluorine-containing gas mixture into a plasma generation volume of a substrate-processing chamber;
applying energy to the fluorine-containing gas mixture to generate a plasma in the plasma generation volume, the plasma comprising fluorine radicals and fluorine ions;
filtering the plasma to provide a reactive gas having a higher concentration of fluorine radicals than fluorine ions;
flowing the reactive gas into a processing volume of the substrate-processing chamber, wherein the processing volume contains a substrate comprising a hafnium oxide containing layer;
exposing the substrate to the reactive gas in the processing volume of the substrate-processing chamber, wherein the reactive gas dopes at least a portion of the hafnium oxide containing layer to form a hafnium oxide containing layer doped with fluorine radicals;
purging the processing volume to remove doping by-products; and,
exposing the hafnium oxide layer doped with fluorine radicals to a nitrogen and hydrogen containing gas mixture and the reactive gas to remove at least a portion of the hafnium oxide layer doped with fluorine radicals, wherein the fluorine-containing gas mixture is free from the nitrogen and hydrogen containing gas mixture.
2. The method of claim 1 , wherein the reactive gas and the nitrogen and hydrogen containing gas mixture are mixed in a dual-zone gas distribution plate prior to entering the processing volume.
3. The method of claim 1 , wherein the fluorine-containing gas mixture comprises NF 3 , F 2 , or both.
4. The method of claim 3 , wherein the fluorine-containing gas mixture further comprises at least one of He or Ar.
5. The method of claim 1 , wherein the nitrogen and hydrogen containing gas mixture comprises N 2 , H 2 , NH 3 , or combinations thereof.
6. The method of claim 5 , wherein the nitrogen and hydrogen containing gas mixture further comprises He or Ar.
7. The method of claim 1 , wherein energy is applied to the fluorine-containing gas mixture using a capacitively coupled plasma unit.
8. The method of claim 1 , wherein the reactive gas is substantially free from fluorine ions.
9. The method of claim 1 , wherein the plasma is filtered using a selective modulation device disposed between the plasma generation volume and the processing volume of the substrate-processing chamber, the selective modulation device comprising a plurality of channels that allow passage of fluorine radicals between the plasma generation volume and the processing volume.
10. A method comprising:
generating a plasma from a fluorine-containing gas mixture, the plasma comprising fluorine radicals and fluorine ions;
removing the fluorine ions from the plasma to provide a reactive gas having a higher concentration of fluorine radicals than fluorine ions;
exposing a substrate comprising a hafnium oxide containing layer to the reactive gas, wherein the reactive gas dopes at least a portion of the hafnium oxide containing layer to form a hafnium oxide containing layer doped with fluorine radicals;
purging the processing volume to remove doping by-products; and,
exposing the hafnium oxide containing layer doped with fluorine radicals to a nitrogen and hydrogen containing gas mixture and the reactive gas to remove at least a portion of the hafnium oxide layer doped with fluorine radicals, wherein the fluorine-containing gas mixture is free from the nitrogen and hydrogen containing gas mixture.
11. The method of claim 10 , wherein the fluorine-containing gas mixture comprises NF 3 , F 2 , or both.
12. The method of claim 11 , wherein the fluorine-containing gas mixture further comprises at least one of He or Ar.
13. The method of claim 10 , wherein the nitrogen and hydrogen containing gas mixture comprises N 2 , H 2 , NH 3 , or combinations thereof.
14. The method of claim 13 , wherein the nitrogen and hydrogen containing gas mixture further comprises He or Ar.
15. A method comprising:
generating a plasma from a fluorine-containing gas mixture comprising NF 3 and He, the plasma comprising fluorine radicals and fluorine ions;
removing a portion of the fluorine ions from the plasma to provide a reactive gas containing the fluorine radicals and substantially free from ions;
exposing a substrate comprising a hafnium oxide-containing layer to the reactive gas, wherein the reactive gas dopes at least a portion of the hafnium oxide-containing layer to form a hafnium oxide-containing layer doped with fluorine radicals;
purging the processing volume to remove doping by-products; and
exposing the hafnium oxide-containing layer doped with fluorine radicals to an ammonia (NH 3 ) containing gas mixture and the reactive gas to remove at least a portion of the hafnium oxide-containing layer doped with fluorine radicals, wherein the fluorine-containing gas mixture is free from the ammonia (NH 3 ) containing gas mixture.
16. The method of claim 15 , wherein the reactive gas and the ammonia (NH 3 ) containing gas mixture are mixed in a dual-zone gas distribution plate.