Method for depositing extremely low resistivity tungsten

Abstract

Methods for depositing extremely low resistivity tungsten in semiconductor processing are disclosed herein. Methods involve annealing the substrate at various times during the tungsten deposition process to achieve uniform tungsten layers with substantially lower resistivity.

What is claimed is: 
     
         1 . A method of forming a tungsten film on a substrate in a reaction chamber, the method comprising:
 depositing tungsten on the substrate by introducing a vapor phase tungsten-containing precursor and a boron-containing reactant into a chamber housing the substrate to form the tungsten film; and   annealing the tungsten film to thereby lower the resistivity,   wherein the tungsten film is annealed at a chamber pressure of at least about 1 Torr, and   wherein annealing the tungsten film reduces the boron content of the tungsten film by a factor of 10.   
     
     
         2 . The method of  claim 1 , wherein the tungsten film is annealed at a temperature between about 385° C. and about 445° C. 
     
     
         3 . The method of  claim 1 , wherein the tungsten film has a boron content of less than about 1%. 
     
     
         4 . The method of  claim 1 , wherein the tungsten film is annealed for a duration between about 1 second and about 10 minutes. 
     
     
         5 . The method of  claim 1 , wherein the tungsten film is annealed in a non-nitrogen atmosphere. 
     
     
         6 . The method of  claim 1 , wherein annealing the tungsten film does not change the chemical composition of the tungsten layer. 
     
     
         7 . The method of  claim 1 , wherein the tungsten film is annealed in a non-silicon atmosphere. 
     
     
         8 . The method of  claim 1 , wherein annealing the tungsten film lowers the resistivity by between about 5% and about 35%. 
     
     
         9 . A method of forming a tungsten film on a substrate in a reaction chamber, the method comprising:
 depositing tungsten on the substrate by introducing a vapor phase tungsten-containing precursor and a boron-containing reactant into a chamber housing the substrate to form the tungsten film at a deposition pressure; and   annealing the tungsten film to thereby lower the resistivity,   wherein the tungsten film is annealed at the deposition pressure, and   wherein annealing the tungsten film reduces the boron content of the tungsten film by a factor of 10.   
     
     
         10 . The method of  claim 9 , wherein the tungsten film has a boron content of less than about 1%. 
     
     
         11 . The method of  claim 9 , wherein the tungsten film is annealed in a non-nitrogen atmosphere. 
     
     
         12 . The method of  claim 9 , wherein annealing the tungsten film does not change the chemical composition of the tungsten layer. 
     
     
         13 . The method of  claim 9 , wherein the tungsten film is annealed in a non-silicon atmosphere. 
     
     
         14 . The method of  claim 9 , wherein annealing the tungsten film lowers the resistivity by between about 5% and about 35%. 
     
     
         15 . The method of  claim 9 , wherein the reaction chamber is a multi-station reactor and the depositing the tungsten and the annealing the tungsten film are performed in different stations of the multi-station reactor. 
     
     
         16 . The method of  claim 9 , wherein flow of a tungsten precursor is shut off after depositing the tungsten and prior to annealing the tungsten film. 
     
     
         17 . The method of  claim 16 , wherein the tungsten film is annealed at a temperature between about 385° C. and about 445° C. 
     
     
         18 . The method of  claim 9 , wherein the deposition pressure is between about 1 mTorr and about 760 Torr. 
     
     
         19 . The method of  claim 18 , wherein the deposition pressure is between about 1 Torr and about 100 Torr. 
     
     
         20 . The method of  claim 9 , wherein the tungsten film is annealed for a duration between about 1 second and about 10 minutes.