Process for producing barrier film and barrier film thus produced

Abstract

A thin nitride film having a low resistance is formed at a low film-forming temperature. In the step of forming a thin nitride film 24 of a high temperature-melting point metal by introducing a feedstock gas having the high temperature-melting point metal and a reductive nitrogen-containing gas having a nitrogen atom into a vacuum atmosphere, an auxiliary reductive gas free from nitrogen is also introduced. The high temperature-melting point metal deposited due to the auxiliary reductive gas compensates for the deficiency of the high temperature-melting point metal of the deposited nitride and thus enable the growth of the thin nitride film 24 having a low resistance.

What is claimed is:  
     
         1 . A process for producing a barrier film which comprises the steps of: 
 providing a substrate in a vacuum atmosphere;    introducing a feedstock gas having a high temperature-melting point metal in its structure and a reductive nitrogen-containing gas comprising a nitrogen atom into said vacuum atmosphere; and    forming a thin film of the nitride of said high temperature-melting point metal on said substrate;    wherein a nitrogen-free auxiliary reductive gas is introduced into said vacuum atmosphere.    
     
     
         2 . The process for producing a barrier film according to  claim 1 , which comprises a step of introducing said auxiliary reductive gas together with said feedstock gas and said reductive nitrogen-containing gas into said vacuum atmosphere.  
     
     
         3 . The process for producing a barrier film according to  claim 2 , which comprises a step of introducing said feedstock gas and said reductive nitrogen-containing gas into said vacuum atmosphere without introducing said auxiliary reductive gas.  
     
     
         4 . The process for producing a barrier film according to  claim 2 , wherein, in the step of introducing said auxiliary reductive gas together with said reductive nitrogen-containing gas and said feedstock gas; 
 said reductive nitrogen-containing gas is introduced at a flow rate once or more higher than the flow rate of said feedstock gas, and said auxiliary reductive gas is introduced at a flow rate once or more but not more than 10 times higher than the flow rate of said reductive nitrogen-containing gas.    
     
     
         5 . The process for producing a barrier film according to  claim 1 , wherein, in the step of introducing said auxiliary reductive gas together with said reductive nitrogen-containing gas and said feedstock gas; 
 said reductive nitrogen-containing gas is introduced at a flow rate once or more but not more than 5 times higher than the flow rate of said feedstock gas, and said auxiliary reductive gas is introduced at a flow rate 2 times or more but not more than 10 times higher than the flow rate of said reductive nitrogen-containing gas.    
     
     
         6 . The process for producing a barrier film according to  claim 2 , wherein, in the step of introducing said auxiliary reductive gas together with said reductive nitrogen-containing gas and said feedstock gas; 
 said auxiliary reductive gas is introduced at a flow rate once or more but not more than 15 times higher than the flow rate of the feedstock gas having said high temperature-melting point metal.    
     
     
         7 . The process for producing a barrier film according to  claim 1 , wherein, in the step of growing the thin film of the nitride of said high temperature-melting point metal; 
 a diluent gas not reacting with said high temperature-melting point metal and a gas having an oxygen atom in its chemical structure are introduced so that the pressure of said vacuum atmosphere is regulated to 1 Pa or more but not more than 100 Pa.    
     
     
         8 . A process for producing a barrier film for forming a barrier film made of a thin film of the nitride of a high temperature-melting point metal on a substrate, wherein; 
 the surface of said substrate is exposed to a plasma of hydrogen gas and a plasma containing at least one gas selected from among argon, nitrogen and helium gases, and then the thin film of the nitride of said high temperature-melting point metal is formed on the surface of the substrate.    
     
     
         9 . A barrier film comprising a thin nitride film of a high temperature-melting point metal, wherein; 
 said thin nitride film has a content of said high temperature-melting point metal exceeding the stoichiometric composition ratio thereof.    
     
     
         10 . A barrier film comprising a thin nitride film of a high temperature-melting point metal formed on a substrate and aiming at preventing the diffusion of metals in an interconnecting thin film formed on said thin nitride film, wherein; 
 said thin nitride film is free from silicon.