Methods for atomic layer etching
Provided are methods of etching a substrate using atomic layer deposition apparatus. Atomic layer deposition apparatus including a gas distribution plate with a thermal element are discussed. The thermal element is capable of locally changing the temperature of a portion of the surface of the substrate to vaporize an etch layer deposited on the substrate.
1. A processing method comprising:
laterally moving a surface beneath a gas distribution plate comprising a plurality of elongate gas ports including a first gas outlet to deliver a first reactive gas, the first reactive gas comprising a fluorine-containing compound;
delivering the first reactive gas to the surface to form an etch layer on the surface;
locally changing the temperature of the surface from a first temperature to a second temperature, the second temperature being sufficient to vaporize the etch layer; and
locally removing the vaporized etch layer from the surface,
wherein the at least one portion of the surface is being exposed to the first reactive gas while the local temperature of a different portion of the surface is being changed.
2. The method of claim 1 , wherein first temperature is below the isotropic etch point of the etch layer and the second temperature is greater than or equal to the isotropic etch point of the etch layer.
3. The method of claim 1 , wherein the surface temperature is changed by one or more of radiative heating or resistive heating.
4. The method of claim 1 , wherein the surface comprises silicon and the first reactive gas comprises fluorine.
5. The method of claim 4 , wherein the second temperature is in the range of about 100° C. to about 200° C.
6. A method of processing a substrate comprising:
laterally moving a surface comprising an oxide beneath a gas distribution plate comprising a plurality of elongate gas ports including a first gas outlet to deliver a first reactive gas and a second gas outlet to deliver a second reactive gas;
delivering the first reactive gas to the surface to form a first reactive layer on the surface, the first reactive gas comprising one or more of ammonia and water;
purging unreacted first reactive gas;
delivering the second reactive gas to the surface to react with the first reactive layer to form an etch layer on the surface, the second reactive gas comprising hydrofluoric acid;
purging unreacted second reactive gas;
locally changing temperature of the surface from a first temperature to a second temperature, the second temperature being sufficient to vaporize the etch layer; and
purging the surface of the vaporized etch layer,
wherein at least one portion of the surface is being exposed to the first reactive gas while at least one different portion of the surface is being exposed to the second reactive gas and the local temperature of a different portion of the surface is being changed.
7. The method of claim 6 , wherein first temperature is below the isotropic etch point of the etch layer and the second temperature is greater than or equal to the isotropic etch point of the etch layer.
8. The method of claim 6 , wherein the surface temperature is changed by one or more of radiative heating or resistive heating.
9. The method of claim 6 , wherein the first reactive gas comprises water and the first temperature is about room temperature and the second temperature is about 50° C.
10. The method of claim 6 , wherein the first reactive gas comprises ammonia and the first temperature is less than about 35° C. and the second temperature is about 120° C.
11. The method of claim 6 , wherein the first temperature is less than about 50° C. and the second temperature is in the range of about 90° C. to about 130° C.