Fluorine-Free Tungsten ALD And Tungsten Selective CVD For Dielectrics

Abstract

Methods of forming metallic tungsten films selectively on a conductive surface relative to a dielectric surface are described. A substrate is exposed to a first process condition to deposit a fluorine-free metallic tungsten film. The fluorine-free metallic tungsten film is exposed to a second process condition to deposit a tungsten film on the fluorine-free metallic tungsten film.

What is claimed is: 
     
         1 . A method comprising:
 exposing a substrate surface to a first process condition comprising a flow of a fluorine-free tungsten precursor and a flow of a first reducing agent to form a fluorine-free metallic tungsten film on the substrate surface to a first thickness; and   exposing the fluorine-free metallic tungsten film to a second process condition comprising a flow of a second tungsten precursor to deposit a tungsten film.   
     
     
         2 . The method of  claim 1 , wherein the fluorine-free tungsten precursor comprises tungsten halides, tungsten hydrohalides, tungsten oxyhalides or combinations thereof. 
     
     
         3 . The method of  claim 1 , wherein the first reducing agent and the second reducing agent independently comprises one or more of hydrogen (H 2 ), silane (SiH 4 ), disilane (Si 2 H 6 ), trisilane (Si 3 H 8 ), tetrasilane (Si 4 H 10 ) or ammonia (NH 3 ). 
     
     
         4 . The method of  claim 1 , wherein the fluorine-free tungsten precursor has a flow rate in a range of from 100 sccm to 700 sccm. 
     
     
         5 . The method of  claim 1 , wherein the fluorine-free tungsten precursor further comprises a co-flown reducing agent, the co-flown reducing agent has a flow rate in the range of 500 to 7000 sccm. 
     
     
         6 . The method of  claim 1 , wherein the first process condition comprises flowing the fluorine-free tungsten precursor and flowing the first reducing agent at a pressure in a range of from 15 psi to 30 psi. 
     
     
         7 . The method of  claim 1 , wherein the first thickness is in the range of 20 Å to 60 Å 
     
     
         8 . The method of  claim 1  further comprising treating the fluorine-free metallic tungsten film with a plasma. 
     
     
         9 . The method of  claim 8 , wherein the plasma treatment causes thermal reduction of the fluorine-free metallic tungsten film. 
     
     
         10 . The method of  claim 8 , wherein the plasma is generated in a range of from 100 W to 1500 W. 
     
     
         11 . The method of  claim 8 , wherein the plasma treatment comprises Hydrogen (H 2 ) plasma treatment, Oxygen (O 2 ) plasma treatment, Argon (Ar) plasma treatment or combinations thereof. 
     
     
         12 . The method of  claim 1 , wherein the second tungsten precursor comprises a tungsten fluoride or derivative thereof. 
     
     
         13 . The method of  claim 1 , wherein the second process condition further comprises co-flowing a second reducing with the second tungsten precursor, the second reducing agent comprises one or more of hydrogen (H 2 ), silane (SiH 4 ), disilane (Si 2 H 6 ), trisilane (Si 3 H 8 ), tetrasilane (Si 4 H 10 ) or ammonia (NH 3 ). 
     
     
         14 . The method of  claim 1  further comprising pre-cleaning the substrate surface before exposing to the first process condition, the pre-cleaning comprises treating the substrate surface with a plasma. 
     
     
         15 . The method of  claim 1 , wherein one or more of the first process condition, plasma treatment or the second process condition are performed at a temperature in a range of from 15° C. to 450° C. 
     
     
         16 . The method of  claim 1 , wherein the substrate surface has a structure formed thereon having a bottom and sidewall, the bottom of the structure comprising a conductive surface and the sidewall of the structure comprising a dielectric surface. 
     
     
         17 . The method of  claim 16 , wherein the fluorine-free metallic tungsten film is deposited selectively on the bottom of the structure relative to the sidewall of the structure, the structure has an aspect ratio in a range of from 2:1 to 4:1. 
     
     
         18 . The method of  claim 16 , wherein the dielectric surface comprises one or more of a SiN x , SiO x , SiO x N y , or combination thereof. 
     
     
         19 . The method of  claim 16 , wherein the conductive surface comprises TiN, TiAl, WC x N y , W or combination thereof. 
     
     
         20 . A method comprising:
 exposing a substrate surface to a first process condition comprising a flow of a fluorine-free tungsten precursor and a flow of a first reducing agent to form a fluorine-free metallic tungsten film on the substrate surface to a first thickness;   treating the fluorine free metallic tungsten film with a plasma; and   exposing the plasma treated fluorine-free metallic tungsten film to a second process condition comprising a flow of a second tungsten precursor to deposit a tungsten film.