Method for forming barrier layer and structure

Abstract

A method for forming barrier layers comprises: first, forming a dual damascene structure on a metal layer of a wafer. The dual damascene structure includes a first dielectric layer and a second dielectric layer. There is a via in the first dielectric layer and there is a trench in the second dielectric layer; second, forming a first tantalum metal layer on the dual damascene structure; third, forming a tantalum nitride layer on the first tantalum metal layer, removing the tantalum nitride layer in the via bottom of the first dielectric layer with a ion-sputtering way and the sputtered tantalum atoms will deposit on the sidewall of the bottom via of the first dielectric layer; finally, forming a second tantalum metal layer, wherein in the bottom via of the first dielectric layer only exist the first tantalum metal layer and the second tantalum metal layer. The accomplished barrier layers will have lower resistivity in the bottom via of the first dielectric layer and they are capable of preventing copper atoms from diffusing into the dielectric layer.

What is claimed is:  
     
         1 . A method for forming a barrier layer, comprising: 
 providing a conductive layer, wherein a first dielectric layer is on said conductive layer and a via is in said first dielectric layer;    forming a first metal layer on said dielectric layer and said conductive layer;    forming a layer of metallized materials on said first metal layer;    bombarding on said layer of metallized materials of said via bottom in said first dielectric layer by ions to make metal atoms bombarded out from said layer of metallized materials deposit on a sidewall of said via in said first dielectric layer; and    forming a second metal layer on said layer of metallized materials.    
     
     
         2 . The method for forming a barrier layer according to  claim 1 , wherein said conductive layer is a copper layer.  
     
     
         3 . The method for forming a barrier layer according to  claim 1 , wherein materials of said first dielectric layer comprises materials of dielectric constant lower than 4.  
     
     
         4 . The method for forming a barrier layer according to  claim 1 , before forming said first metal layer, further comprising forming a second dielectric layer on said first dielectric layer, wherein a trench is in said second dielectric layer and said trench in said second dielectric layer is connected to said via in said first dielectric layer.  
     
     
         5 . The method for forming a barrier layer according to  claim 4 , wherein materials of said second dielectric layer comprises materials of dielectric constant lower than 4.  
     
     
         6 . The method for forming a barrier layer according to  claim 1 , wherein said first metal layer is formed by physical vapor deposition processes.  
     
     
         7 . The method for forming a barrier layer according to  claim 1 , wherein said first metal layer is formed by chemical vapor deposition processes.  
     
     
         8 . The method for forming a barrier layer according to  claim 1 , wherein said first metal layer is a tantalum layer.  
     
     
         9 . The method for forming a barrier layer according to  claim 1 , wherein said layer of metallized materials is formed by physical vapor deposition processes.  
     
     
         10 . The method for forming a barrier layer according to  claim 1 , wherein said layer of metallized materials is formed by chemical vapor deposition processes.  
     
     
         11 . The method for forming a barrier layer according to  claim 1 , wherein said layer of metallized materials is a tantalum nitride layer.  
     
     
         12 . The method for forming a barrier layer according to  claim 1 , wherein said ions are argon ions.  
     
     
         13 . The method for forming a barrier layer according to  claim 1 , wherein said second metal layer is formed by physical vapor deposition processes.  
     
     
         14 . The method for forming a barrier layer according to  claim 1 , wherein said second metal layer is formed by chemical vapor deposition processes.  
     
     
         15 . The method for forming a barrier layer according to  claim 1 , wherein said second metal layer is a tantalum layer.  
     
     
         16 . A barrier layer structure, comprising: 
 a first dielectric layer, said first dielectric layer being formed on a conductive layer and a via being in said first dielectric layer, wherein said via in said first dielectric layer is connected to said conductive layer;    a first metal layer, said first metal layer steppedly covering on said first dielectric layer;    a layer of metallized materials, said layer of metallized materials steppedly covering on said first metal layer, but said layer of metallized materials does not cover said first metal layer above said via bottom connected to said conductive layer in said dielectric layer; and    a second metal layer, said second metal layer steppedly covering on said layer of metallized materials, and said second metal layer covering said first metal layer above said via bottom connected to said conductive layer in said dielectric layer.    
     
     
         17 . The barrier layer structure according to  claim 16 , wherein said conductive layer is a copper layer.  
     
     
         18 . The barrier layer structure according to  claim 16 , wherein materials of said first dielectric layer comprises materials of dielectric constant lower than 4.  
     
     
         19 . The barrier layer structure according to  claim 16 , further comprising a second dielectric layer on said first dielectric layer, wherein a trench is in said second dielectric layer and said trench in said second dielectric layer is connected to said via in said first dielectric layer.  
     
     
         20 . The barrier layer structure according to  claim 16 , wherein materials of said second dielectric layer comprises materials of dielectric constant lower than 4.  
     
     
         21 . The barrier layer structure according to  claim 16 , wherein said first metal layer is a tantalum layer.  
     
     
         22 . The barrier layer structure according to  claim 16 , wherein said layer of metallized materials is a tantalum nitride layer.  
     
     
         23 . The barrier layer structure according to  claim 16 , wherein said second metal layer is a tantalum layer.