Etching process for organic anti-reflective coating

Abstract

A process for selectively removing an anti-reflective coating (ARC) in the manufacturing of semiconductor integrated circuits using an oxygen-free plasma of one or more fluorine containing compounds, chlorine and an optional inert carrier gas. The process renders effective etching of the anti-reflective coating while maintaining dimensional control of a previously etched photoresist.

What is claimed is:  
     
         1 . A process for removing an organic ARC on a metallic layer comprising exposing the ARC to an oxygen-free system of etching agents in an ionized state in a reaction chamber of a plasma generating device, the system of etching agents including one or more fluorine-containing compounds, chlorine and an optional inert carrier gas.  
     
     
         2 . The process of  claim 1 , wherein the one or more fluorine-containing compounds is selected from the group consisting of CF 4 , CHF 3 , C 2 F 6 , CH 2 F 2 , SF 6 , and C n F n+4.    
     
     
         3 . The process of  claim 1 , wherein the ARC is exposed by channels forming an interconnecting network previously etched in a photoresist covering the ARC.  
     
     
         4 . The process of  claim 1 , wherein the system of etching agents consists essential of CHF 3 , Ar, and Cl 2.    
     
     
         5 . The process of  claim 4 , carried out within the following window:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Pressure 
                   about 1 to about 100 millitorr 
                 
                     
                   Temperature 
                   about 30° to about 80° C. 
                 
                     
                   Cl 2  flow 
                   about 5 to about 60 sccm 
                 
                     
                   Ar flow 
                   about 5 to about 80 sccm 
                 
                     
                   CHF 3  flow 
                   about 5 to about 80 sccm. 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         6 . The process of  claim 3 , wherein the ARC on the metallic layer has been used to prevent actinic light passing completely through the photoresist from being reflected from the metallic layer back through the photoresist during the photo etching process.  
     
     
         7 . The process of  claim 1 , wherein the plasma generating device is evacuated to a pressure below 100 mTorr while etching the ARC with the etching agents.  
     
     
         8 . The process of  claim 1 , wherein the plasma generating device comprises an ECR reactor and the ARC is on a semiconductor substrate.  
     
     
         9 . The process of  claim 1 , wherein the ARC is on a semiconductor wafer.  
     
     
         10 . The process of  claim 1 , wherein the plasma generating device includes an antenna which forms the plasma by inductively coupling radio frequency energy into the reaction chamber.  
     
     
         11 . A method for substantially preserving a photoresist while removing exposed areas of an organic ARC during the manufacturing of an integrated circuit comprising exposing the ARC to a system of etching agents in an ionized state in a reaction chamber of a plasma generating device, the system of etching agents including one or more fluorine-containing compounds, an inert carrier gas and chlorine.  
     
     
         12 . The method of  claim 11 , wherein the one or more fluorine-containing compounds is trifluoromethane and the inert carrier gas is argon.  
     
     
         13 . The method of  claim 12 , carried out within the following window  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Pressure 
                   about 1 to about 100 millitorr 
                 
                     
                   Temperature 
                   about 30° to about 80° C. 
                 
                     
                   Cl 2  flow 
                   about 5 to about 60 sccm 
                 
                     
                   Ar flow 
                   about 5 to about 80 sccm 
                 
                     
                   CHF 3  flow 
                   about 5 to about 80 sccm. 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         14 . An oxygen-free plasma etching gas formulation for removing an organic ARC on a metallic layer comprising one or more fluorine-containing compounds, an optional inert carrier gas and chlorine.  
     
     
         15 . The formulation of  claim 14 , wherein the one or more fluorine-containing compounds is CHF 3  and the inert carrier gas is argon.