Electron excitation atomic layer etch

Abstract

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 - 28 . (canceled) 
     
     
         29 . An apparatus for semiconductor processing, the apparatus comprising:
 a processing chamber that includes chamber walls that at least partially bound a chamber interior;   a wafer support for holding a substrate housed in the chamber interior;   a process gas unit configured to flow a first process gas into the chamber interior and onto the substrate in the chamber interior;   an electron source configured to deliver electrons from the electron source to the chamber interior; and   a controller, wherein the controller includes instructions that are configured to:
 cause the process gas unit to flow the first process gas to the processing chamber and cause the substrate in the chamber interior to be exposed to the first process gas, wherein the first process gas is configured to modify one or more layers of material on the substrate to form one or more modified layers, and 
 cause the electron source to generate the electrons and thereby cause the one or more modified surface layers on the substrate to be exposed to the electrons, wherein the one or more modified surface layers are removed, without using a plasma. 
   
     
     
         30 . The apparatus of  claim 29 , wherein the first process gas comprises diatomic chlorine or carbon monoxide. 
     
     
         31 . The apparatus of  claim 29 , wherein the electron source comprises a thermionic source or a field electron emission source. 
     
     
         32 . The apparatus of  claim 31 , wherein the thermionic source comprises lanthanum hexaboride. 
     
     
         33 . The apparatus of  claim 31 , wherein the field electron emission source comprises tungsten zirconium dioxide. 
     
     
         34 . The apparatus of  claim 29 , further comprising a vacuum unit configured to evacuate gases from the chamber interior, wherein the controller further comprises instructions configured to:
 cause the vacuum unit to generate a vacuum in the chamber interior and purge gases from the chamber interior.   
     
     
         35 . The apparatus of  claim 29 , further comprising a charge neutralization unit configured to neutralize a charge of the substrate, wherein the controller further comprises instructions configured to:
 cause the charge neutralization unit to neutralize the charge of the substrate.   
     
     
         36 . The apparatus of  claim 35 , wherein the charge neutralization unit is at least one of: a plasma source, an ultraviolet light source, and the electron source. 
     
     
         37 . The apparatus of  claim 36 , wherein the controller further comprises instructions configured to:
 cause generation of a plasma in the chamber interior,   cause exposure of the substrate to electrons and ions from the electron source, or   cause production of ultraviolet light from the ultraviolet light source, wherein a wavelength of the ultraviolet light is between 50 nm and about 250 nm.   
     
     
         38 . The apparatus of  claim 29 , further comprising a plasma generator configured to generate a plasma in the chamber interior, wherein:
 the plasma generator is one of: a capacitively coupled plasma, an inductively coupled plasma, an upper remote plasma, and a lower remote plasma, and   the controller further comprises instructions configured to cause the plasma generator to generate the plasma in the chamber interior.   
     
     
         39 . The apparatus of  claim 38 , wherein the inductively coupled plasma is set at a plasma between about 50 W and about 2000 W. 
     
     
         40 . The apparatus of  claim 38 , wherein the inductively coupled plasma is set at a bias between 0V and about 500V. 
     
     
       41. The apparatus of  claim 38 , wherein a pulsing frequency is between about 10 Hz and about 200 Hz. 
     
     
         42 . The apparatus of  claim 29 , further comprising an isolation valve or shutter interposed between the chamber interior and the electron source, wherein the isolation valve or shutter are configured to allow the electrons to reach the chamber interior. 
     
     
         43 . An apparatus for semiconductor processing, the apparatus comprising:
 a processing chamber that includes chamber walls that at least partially bound a chamber interior;   a wafer support for holding a substrate housed in the chamber interior;   a process gas unit configured to flow a first process gas and a second process gas into the chamber interior and onto the substrate in the chamber interior;   an electron source configured to deliver electrons from the electron source to the chamber interior; and   a controller, wherein the controller includes instructions that are configured to:
 cause the process gas unit to flow the first process gas and the second process gas to the processing chamber and cause the substrate in the chamber interior to be exposed to the first and the second process gas, wherein the first process gas is configured to modify one or more layers of material on the substrate to form one or more modified layers, and the second process gas is configured to convert the modified layer to one or more converted layers, and 
 cause the electron source to generate the electrons and thereby cause the one or more converted layers on the substrate to be exposed to the electrons, wherein the one or more converted layers are removed, without using a plasma. 
   
     
     
         44 . The apparatus of  claim 43 , wherein the substrate comprises aluminum oxide. 
     
     
         45 . The apparatus of  claim 43 , wherein the first process gas comprises diatomic chloride or carbon monoxide. 
     
     
         46 . The apparatus of  claim 43 , wherein the second process gas comprises dimethylaluminum chloride.