Densifying a relatively porous material

Abstract

An interlayer dielectric may be exposed to a gas cluster ion beam to densify an upper layer of the interlayer dielectric. As a result, the upper layer of the interlayer dielectric may be densified without separate deposition steps and without the need for etch stops that may adversely affect the capacitance of the overall structure.

What is claimed is:  
     
         1 . A method comprising: 
 forming a porous layer; and    exposing said porous layer to a gas clustered ion beam to densify said porous layer.    
     
     
         2 . The method of  claim 1  wherein forming a porous layer includes forming an interlayer dielectric.  
     
     
         3 . The method of  claim 2  including forming a carbon doped oxide interlayer dielectric.  
     
     
         4 . The method of  claim 1  including forming metallic features on said porous layer and exposing said metallic features and said porous layer to a clustered ion beam.  
     
     
         5 . The method of  claim 1  including densifying said porous layer to form a hard mask.  
     
     
         6 . The method of  claim 5  including using said hard mask to enable an unlanded via integration scheme.  
     
     
         7 . The method of  claim 5  including using said hard mask in a damascene or dual damascene process.  
     
     
         8 . The method of  claim 1  including forming said porous layer over a sacrificial layer.  
     
     
         9 . The method of  claim 8  including removing said sacrificial layer through said porous layer and after removing said sacrificial layer through said porous layer exposing said porous layer to said clustered ion beam to form said hard mask.  
     
     
         10 . The method of  claim 1  including densifying only a surface region of said porous layer while the remainder of said porous layer below said surface region remains undensified.  
     
     
         11 . The method of  claim 10  including controlling the thickness of a densified region to approximately 20 Angstroms or less.  
     
     
         12 - 19 . (Canceled).  
     
     
         20 . A method comprising: 
 forming a porous layer over a sacrificial layer;    exhausting at least a portion of said sacrificial layer through said overlying porous layer; and    densifying the porous layer.    
     
     
         21 . The method of  claim 20  including densifying the porous layer using a clustered ion beam.  
     
     
         22 . The method of  claim 21  including forming a non-porous region in said porous layer by densifying.