Atomic layer etching of tungsten for enhanced tungsten deposition fill

Abstract

Methods of depositing tungsten into high aspect ratio features using a dep-etch-dep process integrating various deposition techniques with alternating pulses of surface modification and removal during etch are provided herein.

What is claimed is: 
     
         1 . A method of manufacturing a semiconductor device, the method comprising:
 (a) forming a second metal film on a substrate with a first metal film formed on a surface thereof by alternately supplying a metal-containing gas and a reactive gas onto the substrate;   (b) supplying a modifying gas onto the substrate to modify the second metal film formed on the substrate before supplying an etching gas; and   (c) supplying an etching gas onto the substrate to remove some portions of the second metal film while allowing other portions of the second metal film to remain on the first metal film, wherein some portions of the second metal film is removed by alternately repeating (b) and (c), wherein the second metal film is grown on the first metal film by alternately repeating (a) and (c).   
     
     
         2 . The method of  claim 1 , wherein the modifying gas comprises an oxidizing gas or nitriding gas. 
     
     
         3 . The method of  claim 2 , wherein the etching gas comprises a halide. 
     
     
         4 . The method of  claim 1 , wherein the second metal film comprises a tungsten film or a tungsten nitride film. 
     
     
         5 . The method of  claim 1 , wherein the metal-containing gas comprises tungsten fluoride, the reactive gas comprises one selected from a group consisting of diborane, monosilane and disilane, and the second metal film comprises a tungsten film. 
     
     
         6 . The method of  claim 1 , wherein the substrate includes one or more under-layers, the under-layers including dielectric layers and metal layers. 
     
     
         7 . The method of  claim 1 , wherein the reactive gas includes a reducing gas, wherein the reducing gas includes hydrogen, diborane, monosilane, disilane, or combinations thereof. 
     
     
         8 . The method of  claim 1 , wherein the second metal film is deposited on a feature of the substrate, wherein the feature has an aspect ratio of at least about 10:1. 
     
     
         9 . The method of  claim 8 , wherein supplying the modifying gas comprises directionally modifying the second metal film at or near the opening of the feature relative to the interior of the feature, and wherein supplying the etching gas comprises directionally etching the second metal film at or near the opening of the feature relative to the interior of the feature. 
     
     
         10 . The method of  claim 1 , wherein operations (a), (b), and (c) are performed without breaking vacuum. 
     
     
         11 . A substrate processing apparatus comprising:
 a process chamber in which a substrate is accommodated;   a gas supply system configured to supply a metal-containing gas, a reactive gas, a modifying gas, and an etching gas into the process chamber; and   a controller configured to control the gas supply system to perform:
 (a) forming a second metal film on the substrate with a first metal film formed on a surface thereof by alternately supplying the metal-containing gas and the reactive gas onto the substrate; 
 (b) supplying a modifying gas onto the substrate to modify the second metal film formed on the substrate before supplying an etching gas; and 
 (c) supplying the etching gas onto the substrate to remove some portions of the second metal film while allowing other portions of the second metal film to remain on the first metal film, wherein some portions of the second metal film is removed by alternately repeating (b) and (c), wherein the second metal film is grown on the first metal film by repeating (a) and (c). 
   
     
     
         12 . The substrate processing apparatus of  claim 11 , wherein the gas supply system is configured to supply an oxidizing gas or a nitriding gas as the modifying gas. 
     
     
         13 . The substrate processing apparatus of  claim 12 , wherein the gas supply system is configured to supply a halide as the etching gas. 
     
     
         14 . The substrate processing apparatus of  claim 11 , wherein the second metal film comprises a tungsten film or a tungsten nitride film. 
     
     
         15 . The substrate processing apparatus of  claim 11 , wherein the metal-containing gas comprises tungsten fluoride, the reactive gas comprises one selected from a group consisting of diborane, monosilane and disilane, and the second metal film comprises a tungsten film. 
     
     
         16 . The substrate processing apparatus of  claim 11 , wherein the substrate includes one or more under-layers, the under-layers including dielectric layers and metal layers. 
     
     
         17 . The substrate processing apparatus of  claim 11 , wherein the reactive gas includes a reducing gas, wherein the reducing gas includes hydrogen, diborane, monosilane, disilane, or combinations thereof. 
     
     
         18 . The substrate processing apparatus of  claim 11 , wherein the second metal film is deposited on a feature of the substrate, wherein the feature has an aspect ratio of at least about 10:1. 
     
     
         19 . The substrate processing apparatus of  claim 18 , wherein the controller configured to perform supplying the modifying gas is configured to perform directionally modifying the second metal film at or near the opening of the feature relative to the interior of the feature, and wherein the controller configured to perform supplying the etching gas is configured to perform directionally etching the second metal film at or near the opening of the feature relative to the interior of the feature. 
     
     
         20 . The substrate processing apparatus of  claim 11 , wherein the controller is configured to perform operations (a), (b), and (c) without breaking vacuum.