Plasma-assisted etching of metal oxides

Abstract

The present disclosure describes methods and systems for plasma-assisted etching of a metal oxide. The method includes modifying a surface of the metal oxide with a first gas, removing a top portion of the metal oxide by a ligand exchange reaction, and cleaning the surface of the metal oxide with a second gas.

What is claimed is: 
     
         1 . A system for plasma-assisted etching of a metal oxide, comprising:
 a wafer holder in a chamber configured to hold a wafer with the metal oxide;   a first gas line connected to the chamber and configured to deliver a gas to the chamber;   a plasma generator in the chamber and configured to generate a plasma of the gas;   a plate in the chamber and configured to filter radicals from the plasma of the gas; and   a second gas line connected to the chamber and configured to deliver a precursor across the wafer for a ligand exchange reaction on the metal oxide, wherein the radicals accelerate the ligand exchange reaction.   
     
     
         2 . The system of  claim 1 , further comprising an additional plate between the plasma generator and the plate to distribute a plasma of the gas across the chamber. 
     
     
         3 . The system of  claim 1 , further comprising an additional plate between the plate and the wafer to distribute the precursor across the wafer. 
     
     
         4 . The system of  claim 1 , further comprising a heating system connected to the wafer holder and configured to heat the wafer. 
     
     
         5 . The system of  claim 1 , further comprising a vaporizer connected to the second gas line and configured to vaporize the precursor. 
     
     
         6 . The system of  claim 1 , wherein the gas comprises fluorine and the plasma of the gas fluorinates a surface of the metal oxide before the ligand exchange reaction. 
     
     
         7 . The system of  claim 1 , wherein the gas comprises argon and the radicals of the gas accelerate the ligand exchange reaction. 
     
     
         8 . The system of  claim 1 , wherein the gas comprises hydrogen and the plasma of the gas cleans a surface of the metal oxide after the ligand exchange reaction. 
     
     
         9 . A system for plasma-assisted etching of a metal oxide; comprising:
 a chamber comprising:
 a wafer holder configured to hold a wafer having the metal oxide; and 
 a plasma generator configured to generate a first plasma from a first gas and a second plasma from a second gas; 
   a first gas line connected to a top surface of the chamber and configured to deliver the first gas above the wafer; and   a second gas line connected to a sidewall of the chamber and configured to deliver the second gas across the wafer.   
     
     
         10 . The system of  claim 9 , further comprising a third gas line connected to the top surface of the chamber and configured to deliver a precursor above the wafer for a ligand exchange reaction on the metal oxide. 
     
     
         11 . The system of  claim 9 , wherein the first gas comprises fluorine and the first plasma of the first gas modifies a surface of the metal oxide. 
     
     
         12 . The system of  claim 9 , wherein the second gas comprises hydrogen and the second plasma of the second gas cleans a surface of the metal oxide. 
     
     
         13 . The system of  claim 9 , further comprises an additional chamber connected to the chamber, wherein the additional chamber comprises:
 an additional wafer holder configured to hold the wafer with the metal oxide;   a fourth gas line connected to the additional chamber and configured to deliver a precursor above the wafer for a ligand exchange reaction on the metal oxide; and   a connector configured to connect the chamber to the additional chamber and transfer the wafer between the chamber and the additional chamber.   
     
     
         14 . The system of  claim 13 , wherein the additional chamber further comprises a plate configured to distribute the precursor across the wafer. 
     
     
         15 . The system of  claim 13 , wherein the additional chamber further comprises a heating system connected to the additional wafer holder and configured to heat the wafer. 
     
     
         16 . A method for plasma-assisted etching of a metal oxide, comprising:
 providing a wafer having the metal oxide in a chamber, wherein the wafer is held by a wafer holder in the chamber;   delivering a gas to the chamber via a first gas line connected to the chamber;   generating a plasma of the gas with a plasma generator in the chamber;   filtering radicals from the plasma of the gas with a plate in the chamber; and   delivering, via a second gas line connected to the chamber, a precursor to the wafer for a ligand exchange reaction on the metal oxide, wherein the radicals accelerate the ligand exchange reaction.   
     
     
         17 . The method of  claim 16 , further comprising distributing the plasma of the gas across the chamber with an additional plate between the plasma generator and the plate. 
     
     
         18 . The method of  claim 16 , further comprising distributing the precursor across the wafer with an additional plate between the plate and the wafer. 
     
     
         19 . The method of  claim 16 , further comprising heating the wafer with a heating system connected to the wafer holder. 
     
     
         20 . The method of  claim 16 , further comprising vaporizing the precursor with a vaporizer connected to the second gas line.