Refractory metal nitride barrier layer with gradient nitrogen concentration

Abstract

Within a microelectronic fabrication and a method for fabricating the microelectronic fabrication a barrier layer is formed over a substrate. Within the method and the microelectronic fabrication the barrier layer is formed of a refractory metal nitride barrier material having within its thickness a gradient in nitrogen concentration. The barrier layer has low resistivity and improved electromigration performance.

1 - 9 . (canceled)  
   
   
       10 . A method for fabricating a microelectronic fabrication comprising: 
 providing a substrate; and    forming over the substrate a barrier layer, the barrier layer comprising a refractory metal nitride barrier material having within its thickness a gradient in nitrogen concentration.    
   
   
       11 . The method of  claim 10  wherein the substrate is employed within a microelectronic fabrication selected from the group consisting of integrated circuit microelectronic fabrications, ceramic substrate microelectronic fabrications, solar cell optoelectronic microelectronic fabrications, sensor image array optoelectronic microelectronic fabrications and display image array optoelectronic microelectronic fabrications.  
   
   
       12 . The method of  claim 10  wherein the gradient encompasses a substantially stoichiometric refractory metal nitride barrier material composition at a first side of the barrier layer and a nitrogen deficient refractory metal nitride barrier material composition at an opposite second side of the barrier layer.  
   
   
       13 . The method of  claim 12  wherein the nitrogen deficient refractory metal nitride barrier material composition has a metal:nitrogen atomic ratio of from about 1:0.8 to about 1:0.2.  
   
   
       14 . The method of  claim 12  wherein: 
 the substantially stoichiometric refractory metal nitride barrier material composition is formed to a thickness of from about 50 to about 400 angstroms; and    the nitrogen deficient refractory metal nitride barrier material composition is formed to a thickness of from about 300 to about 30 angstroms.    
   
   
       15 . The method of  claim 10  wherein a refractory metal employed within the refractory metal nitride material is selected from the group consisting of titanium, tungsten and tantalum, zirconium and silicides thereof.  
   
   
       16 . The method of  claim 10  wherein a refractory metal employed within the refractory metal nitride material is tantalum.  
   
   
       17 . The method of  claim 12  further comprising forming a dielectric layer adjacent the first side of the barrier layer and forming a copper containing conductor layer adjacent the second side of the barrier layer.  
   
   
       18 . The method of  claim 17  further comprising forming a refractory metal layer upon the second side of the barrier layer and interposed between the barrier layer and the copper containing conductor layer.  
   
   
       19 . The method of  claim 10  wherein the barrier layer is formed employing a method selected from the group consisting of physical vapor deposition (PVD) methods and chemical vapor deposition (CVD) methods.  
   
   
       20 . The method of  claim 10  wherein the barrier layer is formed employing a reactive sputtering physical vapor deposition (PVD) method employing a varied nitrogen concentration within a sputtering atmosphere.