Dual damascene integration structures and method of forming improved dual damascene integration structures

Abstract

Methods of densifying a porous ultra-low-k (ULK) dielectric material by using gas-cluster ion-beam processing are disclosed. Methods for gas-cluster ion-beam etching, densification, pore sealing and ashing are described that allow simultaneous removal of material and densification of the ULK interfaces. A novel ULK dual damascene structure is disclosed with densified interfaces and no hard-masks.

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 densifying only a surface region of said porous layer while the remainder of said porous layer below said surface region remains undensified. 
   
   
       9 . The method of  claim 8 , including controlling the thickness of a densified region from less than about 50 Angstroms to more than about 350 Angstroms. 
   
   
       10 . The method of  claim 8 , including controlling the thickness of a densified region to approximately 50 Angstroms or less.