Systems and methods for back end of line processing of semiconductor circuits

Abstract

A BEOL manufacturing process for forming a via on a semiconductor wafer comprises depositing a portion of a first metal adhesion layer within a patterned via hole, followed by a cooling step. The cooling step is then followed by formation of the remainder of the first metal adhesion layer and formation of a second metal adhesion layer within the patterned via hole. This process of forming the remaining portion of the first metal adhesion layer can be referred to as a load, unload, load (LUL) process. By using a LUL process, thermal processing is minimized, which reduces Al extrusion at the via interfaces.

1 . A method for forming via on a semiconductor wafer in a back end of the line (BEOL) process, comprising:
 patterning a via hole for formation of the via;   forming a portion of a first metal adhesion layer in the patterned via hole;   cooling the wafer;   forming the remaining portion of the first metal adhesion layer in the patterned via hole; and   forming a second metal adhesion layer inside the first metal adhesion layer within the patterned via hole.   
   
   
       2 . The method of  claim 1 , further comprising cleaning the wafer before forming the portion of the first metal adhesion layer. 
   
   
       3 . The method of  claim 2 , further comprising cooling the wafer after cleaning the wafer and before forming the portion of the first metal adhesion layer. 
   
   
       4 . The method of  claim 1 , further comprising cooling the wafer after forming the second metal adhesion layer. 
   
   
       5 . The method of  claim 1 , wherein forming the portion of the first metal adhesion layer comprises depositing the portion of the first metal adhesion layer within the patterned via hole. 
   
   
       6 . The method of  claim 5 , wherein the portion of the first metal adhesion layer is deposited using physical vapor deposition. 
   
   
       7 . The method of  claim 1 , wherein forming the remainder of the first metal adhesion layer comprises depositing the remainder of the first metal adhesion layer within the patterned via hole. 
   
   
       8 . The method of  claim 7 , wherein the remainder of the first metal adhesion layer is deposited using physical vapor deposition. 
   
   
       9 . The method of  claim 1 , wherein forming the second metal adhesion layer comprises depositing the second metal adhesion layer within the patterned via hole. 
   
   
       10 . The method of  claim 9 , wherein the portion of the first metal adhesion layer is deposited using metal organic chemical vapor deposition. 
   
   
       11 . The method of  claim 1 , further comprising forming a metal plug inside the first and second metal adhesion layers within the patterned via hole. 
   
   
       12 . A method for forming via on a semiconductor wafer in a back end of the line (BEOL) process, comprising:
 forming a first metal layer;   patterning a via hole for formation of the via;   forming a portion of a first metal adhesion layer in the patterned via hole;   cooling the wafer;   forming the remaining portion of the first metal adhesion layer in the patterned via hole;   forming a second metal adhesion layer within the first metal adhesion layer within the patterned via hole;   forming a metal plug inside the first and second metal adhesion layers within the patterned via hole.   
   
   
       13 . The method of  claim 12 , further comprising cleaning the wafer before forming the portion of the first metal adhesion layer. 
   
   
       14 . The method of  claim 13 , further comprising cooling the wafer after cleaning the wafer and before forming the portion of the first metal adhesion layer. 
   
   
       15 . The method of  claim 12 , further comprising cooling the wafer after forming the second metal adhesion layer. 
   
   
       16 . The method of  claim 12 , wherein forming the portion of the first metal adhesion layer comprises depositing the portion of the first metal adhesion layer within the patterned via hole. 
   
   
       17 . The method of  claim 16 , wherein the portion of the first metal adhesion layer is deposited using physical vapor deposition. 
   
   
       18 . The method of  claim 12 , wherein forming the remainder of the first metal adhesion layer comprises depositing the remainder of the first metal adhesion layer within the patterned via hole. 
   
   
       19 . The method of  claim 18 , wherein the remainder of the first metal adhesion layer is deposited using physical vapor deposition. 
   
   
       20 . The method of  claim 12 , wherein forming the second metal adhesion layer comprises depositing the second metal adhesion layer within the patterned via hole. 
   
   
       21 . The method of  claim 20 , wherein the portion of the first metal adhesion layer is deposited using metal organic chemical vapor deposition. 
   
   
       22 . The method of  claim 12 , wherein forming the portion of the first metal adhesion layer comprises heating the wafer to approximately 200° C. 
   
   
       23 . The method of  claim 22 , wherein forming the portion of the first metal adhesion layer comprises heating the wafer for approximately 49 seconds. 
   
   
       24 . The method of  claim 12 , wherein forming the remainder of the first metal adhesion layer comprises heating the wafer to approximately 200° C. 
   
   
       25 . The method of  claim 24 , wherein forming the remainder of the first metal adhesion layer comprises heating the wafer for approximately 49 seconds. 
   
   
       26 . The method of  claim 12 , wherein forming the second metal adhesion layer comprises heating the wafer to approximately 450° C. 
   
   
       27 . The method of  claim 26 , wherein forming the second metal adhesion layer comprises heating the wafer for approximately 177 seconds.