Atomic layer etching methods and apparatus

Abstract

A multi-station process tool for performing atomic layer etching of a surface of a substrate, includes: a first station having a first pedestal that supports the substrate when in the first station, the first pedestal being heated to a first predefined temperature; wherein the first station is configured to perform a surface conversion operation, by exposing an entirety of the surface of the substrate to a surface conversion reactant; a second station having a second pedestal that supports the substrate when in the second station, the second pedestal being heated to a second predefined temperature; wherein the second station is configured to perform a ligand exchange operation, by exposing the entirety of the surface of the substrate to a ligand containing reactant, wherein the second pedestal being heated to the second predefined temperature causes desorption of surface species, generated from the ligand exchange operation, from the surface of the substrate.

What is claimed is: 
     
         1 : A multi-station process tool for performing atomic layer etching of a surface of a substrate that is exposed for processing, comprising:
 a first station having a first pedestal that supports the substrate when in the first station, the first pedestal being heated to a first predefined temperature;   wherein the first station is configured to perform a surface conversion operation on the substrate, by exposing an entirety of the surface of the substrate to a surface conversion reactant;   a second station having a second pedestal that supports the substrate when in the second station, the second pedestal being heated to a second predefined temperature;   wherein the second station is configured to perform a ligand exchange operation on the substrate, by exposing the entirety of the surface of the substrate to a ligand containing reactant, wherein the second pedestal being heated to the second predefined temperature causes desorption of surface species, generated from the ligand exchange operation, from the surface of the substrate.   
     
     
         2 : The multi-station process tool of  claim 1 , wherein the surface conversion reactant adsorbs or chemisorbs on the surface of the substrate and modifies surface species on the surface of the substrate, wherein the surface conversion operation is substantially self-limiting;
 wherein the ligand containing reactant reacts with the modified surface species to form ligand-substituted species that are desorbed from the surface of the substrate.   
     
     
         3 : The multi-station process tool of  claim 1 , wherein the second predefined temperature is higher than the first predefined temperature. 
     
     
         4 : The multi-station process tool of  claim 1 , further comprising:
 a third station having a third pedestal that supports the substrate when in the third station, the third pedestal being heated to the first predefined temperature;   wherein the third station is configured to perform the surface conversion operation on the substrate, by exposing an entirety of the surface of the substrate to the surface conversion reactant;   a fourth station having a fourth pedestal that supports the substrate when in the fourth station, the fourth pedestal being heated to the second predefined temperature;   wherein the fourth station is configured to perform the ligand exchange operation on the substrate, by exposing the entirety of the surface of the substrate to the ligand containing reactant, wherein the fourth pedestal being heated to the second predefined temperature causes desorption of surface species, generated from the ligand exchange operation, from the surface of the substrate.   
     
     
         5 : The multi-station process tool of  claim 4 , further comprising:
 a rotating mechanism that moves the substrate between the first, second, third, and fourth stations of the multi-station process tool.   
     
     
         6 : The multi-station process tool of  claim 4 , wherein the first, second, third, and fourth stations enable simultaneous processing of four substrates by the multi-station process tool. 
     
     
         7 : A multi-station process tool for performing atomic layer etching of a surface of a substrate that is exposed for processing, comprising:
 a first station having a first pedestal that supports the substrate when in the first station, the first pedestal being heated to a first predefined temperature;   wherein the first station is configured to perform a surface conversion operation on the substrate, by exposing an entirety of the surface of the substrate to a surface conversion reactant;   a second station having a second pedestal that supports the substrate when in the second station, the second pedestal being heated to a second predefined temperature;   wherein the second station is configured to perform a ligand exchange operation on the substrate, by exposing the entirety of the surface of the substrate to a ligand containing reactant;   a third station having a third pedestal that supports the substrate when in the third station, the third pedestal being heated to a third predefined temperature, wherein the third pedestal being heated to the third predefined temperature causes desorption of surface species, generated from the ligand exchange operation, from the surface of the substrate.   
     
     
         8 : The multi-station process tool of  claim 7 , wherein the surface conversion reactant adsorbs or chemisorbs on the surface of the substrate and modifies surface species on the surface of the substrate, wherein the surface conversion operation is substantially self-limiting;
 wherein the ligand containing reactant reacts with the modified surface species to form ligand-substituted species that are desorbed from the surface of the substrate.   
     
     
         9 : The multi-station process tool of  claim 7 , wherein the first, second, and third predefined temperatures are different from each other. 
     
     
         10 : The multi-station process tool of  claim 9 , wherein the third predefined temperature is higher than the second predefined temperature, and the second predefined temperature is higher than the first predefined temperature. 
     
     
         11 : The multi-station process tool of  claim 7 , further comprising:
 a rotating mechanism that moves the substrate between the first, second, and third stations of the multi-station process tool.   
     
     
         12 : The multi-station process tool of  claim 7 , wherein the first, second, and third stations enable simultaneous processing of a plurality of substrates by the multi-station process tool. 
     
     
         13 : A multi-station process tool for performing atomic layer etching of a surface of a substrate that is exposed for processing, comprising:
 a first station having a first pedestal that supports the substrate when in the first station, the first pedestal being heated to a first predefined temperature;   wherein the first station is configured to perform a first reaction on the substrate, by exposing an entirety of the surface of the substrate to a first reactant;   a second station having a second pedestal that supports the substrate when in the second station, the second pedestal being heated to a second predefined temperature;   wherein the second station is configured to perform a second reaction on the substrate, by exposing the entirety of the surface of the substrate to a second reactant, wherein the second pedestal being heated to the second predefined temperature causes desorption of surface species, generated from the second reaction, from the surface of the substrate.   
     
     
         14 : The multi-station process tool of  claim 13 , wherein the first reactant adsorbs or chemisorbs on the surface of the substrate and modifies surface species on the surface of the substrate, wherein the first reaction is substantially self-limiting. 
     
     
         15 : The multi-station process tool of  claim 14 , wherein the second reactant reacts with the modified surface species to produce a substitution, condensation or chelation reaction, that transforms the modified surface species to enable the desorption from the surface of the substrate. 
     
     
         16 : The multi-station process tool of  claim 13 , wherein the second predefined temperature is higher than the first predefined temperature. 
     
     
         17 : The multi-station process tool of  claim 13 , further comprising:
 a third station having a third pedestal that supports the substrate when in the third station, the third pedestal being heated to the first predefined temperature;   wherein the third station is configured to perform the first reaction on the substrate, by exposing an entirety of the surface of the substrate to the first reactant;   a fourth station having a fourth pedestal that supports the substrate when in the fourth station, the fourth pedestal being heated to the second predefined temperature;   wherein the fourth station is configured to perform the second reaction on the substrate, by exposing the entirety of the surface of the substrate to the second reactant, wherein the fourth pedestal being heated to the second predefined temperature causes desorption of surface species, generated from the second reaction, from the surface of the substrate.   
     
     
         18 : The multi-station process tool of  claim 17 , further comprising:
 a rotating mechanism that moves the substrate between the first, second, third, and fourth stations of the multi-station process tool.   
     
     
         19 : The multi-station process tool of  claim 17 , wherein the first, second, third, and fourth stations enable simultaneous processing of four substrates by the multi-station process tool.