Method of manufacturing a barrier metal layer using atomic layer deposition

Abstract

A method of manufacturing a barrier metal layer uses atomic layer deposition (ALD) as the mechanism for depositing the barrier metal. The method includes supplying a first source gas onto the entire surface of a semiconductor substrate in the form of a pulse, and supplying a second source gas, which reacts with the first source gas, onto the entire surface of the semiconductor substrate in the form of a pulse. In a first embodiment, the pulses overlap in time so that the second source gas reacts with part of the first source gas physically adsorbed at the surface of the semiconductor substrate to thereby form part of the barrier metal layer by chemical vapor deposition whereas another part of the second source gas reacts with the first source gas chemically adsorbed at the surface of the semiconductor substrate to thereby form part of the barrier metal layer by atomic layer deposition. Thus, the deposition rate is greater than if the barrier metal layer were only formed by ALD. In the second embodiment, an impurity-removing gas is used to remove impurities in the barrier metal layer. Thus, even if the gas supply scheme is set up to only use ALD in creating the barrier metal layer, the deposition rate can be increased without the usual accompanying increase in the impurity content of the barrier metal layer.

What is claimed is:  
     
         1 . A method of manufacturing a barrier metal layer, comprising the steps of: 
 loading a semiconductor substrate into a processing chamber;    supplying a first source gas, containing a metal, onto the entire surface of the semiconductor substrate in the form of a pulse having a duration lasting from a point in time A 1  to a point in time A 2 , whereby the first source gas is chemically and physically adsorbed at the surface; and    supplying a second source gas, that is reactive with the first source gas to form the barrier metal, onto the entire surface of the semiconductor substrate in the form of a pulse having a duration lasting from a point in time A 3  to a point in time A 4 , wherein said point in time A 3  is no earlier than said point in time A 1  and no later than said point in time A 2 , whereby one portion of the second source gas reacts with that part of the first source gas physically adsorbed at the surface of the semiconductor substrate to thereby form the barrier metal layer by chemical vapor deposition whereas another part of the second source gas reacts with that part of the first source gas chemically adsorbed at the surface of the semiconductor substrate to thereby form the barrier metal layer by atomic layer deposition.    
     
     
         2 . The method of  claim 1 , wherein said point in time A 4  is no later in time than said point in time A 2 .  
     
     
         3 . The method of  claim 1 , and further comprising supplying a purge gas onto the entire surface of the semiconductor substrate beginning at a point in time that is no later than said point in time A 1 .  
     
     
         4 . The method of  claim 1 , and further comprising supplying a purge gas onto the entire surface of the semiconductor substrate beginning at a point in time that is later than said point in time A 1  and no later than said point in time A 3 .  
     
     
         5 . The method of  claim 1 , wherein the first source gas includes an element of the halogen family and a refractory metal, and the second source gas includes nitrogen.  
     
     
         6 . The method of  claim 1 , and further comprising supplying a purge gas onto the entire surface of the semiconductor substrate for a predetermined period of time after said point in time A 4  to discharge by-products of the reaction between the first and second source gases.  
     
     
         7 . The method of  claim 6 , wherein said steps of supplying the first source gas in the form of a pulse, supplying the second source gas in the form of a pulse, and supplying the purge gas for a predetermined period of time are repeated at least once to increase the thickness of the barrier metal layer.  
     
     
         8 . The method of  claim 1 , wherein the reaction of the first and second source gases produces an impurity trapped in the barrier metal layer, and further comprising supplying a purge gas onto the entire surface of the semiconductor substrate, and supplying an impurity-removing gas, capable of reacting with the impurity, onto the entire surface of the semiconductor substrate for a predetermined period of time beginning after point in time A 4  and while the purge gas is being supplied, in order to remove impurities from the barrier metal layer.  
     
     
         9 . The method of  claim 8 , wherein the impurity removing-gas is NH 3 .  
     
     
         10 . The method of  claim 8 , wherein said steps of supplying the first source gas in the form of a pulse, supplying the second source gas in the form of a pulse, and supplying the impurity-removing gas are repeated at least once to increase the thickness of the barrier metal layer.  
     
     
         11 . The method of  claim 11 , wherein said point in time A 1  coincides with said point in time A 3 , and said point in time A 2  coincides with said point in time A 4 .  
     
     
         12 . A method of manufacturing a barrier metal layer, comprising the steps of: 
 loading a semiconductor substrate into a processing chamber;    supplying a first source gas, containing a metal, onto the entire surface of the semiconductor substrate in the form of a pulse having a duration lasting from a point in time B 1  to a point in time B 2 , whereby the first source gas is chemically and physically adsorbed at the surface;    supplying a second source gas, that is reactive with the first source gas to form the barrier metal, onto the entire surface of the semiconductor substrate in the form of a pulse having a duration lasting from a point in time B 3  to a point in time B 4 , whereby part of the second source gas reacts with that part of the first source gas chemically adsorbed at the surface of the semiconductor substrate to thereby form the barrier metal layer by atomic layer deposition; and    supplying an impurity-removing gas onto the entire surface of the semiconductor substrate in the form of a pulse having a duration lasting from a point in time B 5  that is later than said point in time B 4 , to a point in time B 6  to thereby remove impurities from the barrier metal layer.    
     
     
         13 . The method of  claim 12 , wherein said point in time B 3  is later in time than said point in time B 2 , and further comprising supplying a purge gas onto the entire surface of the semiconductor substrate beginning at a point in time that is no later than said point in time B 1  to purge the substrate of the first source gas physically adsorbed at the surface thereof before the second source gas is supplied.  
     
     
         14 . The method of  claim 12 , wherein said point in time B 3  is later in time than said point in time B 2 , and further comprising supplying a purge gas onto the entire surface of the semiconductor substrate beginning at a point in time that is later than said point in time B 1  and is no later than aid point in time B 2  to purge the substrate of the first source gas physically adsorbed at the surface thereof before the second source gas is supplied.  
     
     
         15 . The method of  claim 12 , wherein the first source gas includes an element of the halogen family and a refractory metal, and the second source gas includes nitrogen.  
     
     
         16 . The method of  claim 12 , wherein said steps of supplying the first source gas in the form of a pulse, supplying the second source gas in the form of a pulse, and supplying the impurity-removing gas in the form of a pulse are repeated at least once to increase the thickness of the barrier metal layer.  
     
     
         17 . The method of  claim 12 , wherein the impurity-removing gas is NH 3 .