Forming cobalt interconnections on a substrate

Abstract

A wafer electroplating system has at least one first electroplating chamber having a first electrolyte containing cobalt ions, and is adapted to electroplate a cobalt film onto a wafer at a first deposition rate. A second electroplating chamber has a second electrolyte containing cobalt ions, and is adapted to electroplate a cobalt film onto the wafer at a second deposition rate faster than the first deposition rate. The first and second electroplating chambers are within an enclosure of a processing system. A robot moves a wafer among the first and second electroplating chambers.

1 . A processing method comprising:
 A] placing a wafer into a first electroplating chamber having a first electrolyte containing cobalt ions;   B] electroplating a first cobalt film onto the wafer at a first deposition rate;   C] rinsing and drying the wafer; and   after performing step C;   D] placing the wafer into a second electroplating chamber having a second electrolyte containing cobalt ions; and   E] electroplating a second cobalt film onto the wafer at a second deposition rate faster than the first deposition rate.   
     
     
         2 . The method of  claim 1  wherein the first and second electroplating chambers are within a single enclosure, and further including annealing the wafer within the enclosure after step B and before step C. 
     
     
         3 . The method of  claim 1  further including plasma or thermally pretreating the wafer within the enclosure. 
     
     
         4 . The method of  claim 1  further including annealing the wafer before step D. 
     
     
         5 . The method of  claim 4  further including annealing the wafer after step B and then repeating step B at least once. 
     
     
         6 . The method of  claim 1  wherein in step B the first electrolyte touches an entire down-facing surface of the wafer. 
     
     
         7 . The method of  claim 6  wherein in step D, the second electrolyte is sealed off from electrical contacts at a perimeter of the wafer. 
     
     
         8 . The method of  claim 1  further including annealing the wafer after step D. 
     
     
         9 . The method of  claim 1  wherein the first electrolyte is different from the second electrolyte. 
     
     
         10 . A processing method comprising:
 A] placing a wafer into a first electroplating chamber having a first electrolyte containing cobalt ions;   B] electroplating a first cobalt film onto the wafer at a first deposition rate;   C] placing the wafer into a second electroplating chamber having a second electrolyte containing cobalt ions; and   D] electroplating a second cobalt film onto the wafer at a second deposition rate faster than the first deposition rate; and   E] with steps A, B, C and D performed in the sequence as listed.   
     
     
         11 . The method of  claim 10  further including rinsing and drying the wafer after step B. 
     
     
         12 . The method of  claim 10  with step D creating an overburden cobalt layer on the wafer, and further including chemically mechanically polishing the wafer. 
     
     
         13 . The method of  claim 10  wherein the first and second electroplating chambers are within a single enclosure, and further including annealing the wafer within the enclosure after step B and before step C. 
     
     
         14 . The method of  claim 10  further including plasma or thermally pretreating the wafer within the enclosure. 
     
     
         15 . The method of  claim 10  further including annealing the wafer before step D. 
     
     
         16 . The method of  claim 15  further including annealing the wafer after step B and then repeating step B at least once. 
     
     
         17 . The method of  claim 10  wherein in step B the first electrolyte touches an entire down-facing surface of the wafer. 
     
     
         18 . The method of  claim 17  wherein in step D, the second electrolyte is sealed off from electrical contacts at a perimeter of the wafer. 
     
     
         19 . The method of  claim 10  further including annealing the wafer after step D. 
     
     
         20 . A processing method comprising:
 A] placing a wafer into a first electroplating chamber having a first electrolyte containing cobalt ions;   B] electroplating a first cobalt film onto the wafer at a first deposition rate, with the first electrolyte touching an entire down-facing surface of the wafer;   C] placing the wafer into a second electroplating chamber having a second electrolyte containing cobalt ions; and   D] electroplating a second cobalt film onto the wafer at a second deposition rate two to twenty times faster than the first deposition rate, and with the second electrolyte sealed off from electrical contacts at a perimeter of the wafer;   E] wherein steps A, B, C and D performed in the sequence as listed; and   F] the first and second electroplating chambers are within a single enclosure, and further including annealing the wafer within the enclosure after step B and before step C.