Wafer processing apparatus & methods for depositing cobalt silicide

Abstract

A cluster tool and a number of different processes for making a cobalt-silicide material are disclosed. Combinations of alloyed layers of Co—Ti—along with layers of Co—are arranged and heat treated so as to effectuate a silicide reaction. The resulting structures have extremely low resistance, and show little line width dependence, thus making them particularly attractive for use in semiconductor processing. A cluster tool is configured with appropriate sputter targets/heat assemblies to implement many of the needed operations for the silicide reactions, thus resulting in higher savings, productivity, etc.

1 - 23 . (canceled)  
   
   
       24 . A cluster tool for performing semiconductor processing operations on a wafer, the cluster tool comprising: 
 (a) a load lock chamber for receiving the wafer; and    (b) a sputter chamber coupled to the load lock chamber so that the wafer can be transported without breaking vacuum, said sputter chamber being equipped with a cobalt alloy target for sputtering a target material on the wafer; 
 said sputter chamber being further configured such that it can be purged of oxygen and nitrogen prior to a sputtering operation;  
   (c) a heat annealing apparatus for heating the wafer at a rate and temperature sufficient to cause a silicide reaction between the sputtered target material and the wafer; 
 wherein the heat annealing apparatus is coupled to the sputter chamber so that the wafer is not exposed to a contaminant containing ambient between steps (b) and (c).  
   
   
   
       25 . The cluster tool of  claim 24 , wherein said load lock chamber is used for outgassing of the wafer.  
   
   
       26 . The cluster tool of claim  20 , wherein said sputter chamber and said heat annealing apparatus are integrated in a single processing station.  
   
   
       27 . The cluster tool of claim  20 , further including a second sputter chamber equipped with a second target including cobalt for sputtering a second target material on the wafer.  
   
   
       28 . The cluster tool of claim  20 , further including a cleaning station for performing a cleaning operation on the wafer prior to any sputter operation.  
   
   
       29 . The cluster tool of claim  20 , wherein a target for said sputter chamber is adjustable in situ so that two different target materials can be deposited on the wafer without changing locations.  
   
   
       30 - 32 . (canceled)  
   
   
       33 . A cluster tool for performing semiconductor processing operations on a wafer, the cluster tool comprising: 
 (a) a cleaning chamber adapted to remove oxide from the wafer;    (b) a first sputter chamber equipped with a cobalt target for sputtering a first target material on the wafer;    (c) a second sputter chamber equipped with a cobalt and refractory metal alloy target for sputtering a second target material on the wafer;    (d) a wafer handler for transporting the wafer so that it is not exposed to air at least between the first sputter chamber and second sputter chamber;    (e) a heat annealing apparatus integrated within the cluster tool for heating the wafer at a rate and temperature sufficient to cause a silicide reaction on the wafer; 
 wherein the heat annealing apparatus is adapted within the cluster tool so that the wafer is not exposed to a contaminant containing ambient between steps (d) and (e).  
   
   
   
       34 . The cluster tool of  claim 33 , wherein the cleaning chamber uses a sputtering operation.  
   
   
       35 . The cluster tool of  claim 33 , wherein the first target material includes between about 80-100 Angstroms of Cobalt.  
   
   
       36 . The cluster tool of  claim 33 , wherein the refractory metal includes one or more of: Ti, Ta, W, Mo, Zr, Hf and/or Nb.  
   
   
       37 . The cluster tool of  claim 33  wherein the heat annealing apparatus is integrated as part of said second sputter chamber.  
   
   
       38 . The cluster tool of  claim 33  wherein the heat annealing apparatus is located within a separate anneal chamber.  
   
   
       39 . The cluster tool of  claim 33 , wherein a ternary target is used in said second sputter chamber to form an additional layer on said second target material.  
   
   
       40 . The cluster tool of  claim 33 , wherein a ternary target is used in said second sputter chamber to form an additional layer on said second target material.  
   
   
       41 . A cluster tool for performing semiconductor processing operations on a wafer, the cluster tool comprising: 
 (a) a cleaning chamber adapted to remove oxide from the wafer;    (b) a first sputter chamber equipped with a first metal target including cobalt and a refractory metal and configured to sputter a first target material on the wafer;    (c) a second sputter chamber equipped with a second metal target and configured to sputter a second target material on said first target material, which second target material has a higher concentration of cobalt than a layer formed on the wafer by said first target material; 
 wherein the second sputter chamber includes an integrated heater to facilitate formation of Co2Si and/or CoSi during sputtering;  
   (d) a wafer handler for transporting the wafer so that it is not exposed to air at least between the first sputter chamber and second sputter chamber.    
   
   
       42 . The cluster tool of  claim 41 , wherein said first target material is used to form a layer of about 5 to 15 nm on the wafer.  
   
   
       43 . The cluster tool of  claim 41 , wherein said second metal target includes only Cobalt.  
   
   
       44 . The cluster tool of  claim 41 , wherein said first metal target includes a concentration of said refractory metal in excess of 50 atomic percent.  
   
   
       45 . The cluster tool of  claim 41 , further including a heat annealing apparatus integrated within the cluster tool for heating the wafer at a rate and temperature sufficient to cause a silicide reaction on the wafer.  
   
   
       46 . The cluster tool of  claim 45  wherein the heat annealing apparatus is adapted within the cluster tool so that the wafer is not exposed to a contaminant containing ambient.