Method and system for automatically controlling a current distribution of a multi-anode arrangement during the plating of a metal on a substrate surface

Abstract

An electroplating tool is operated in combination with a controller which automatically determines the individual currents for a multi-anode configuration of the plating tool. The calculation of the anode currents may be based on sensitivity data and measurement data as well as on a desired target profile, so that a fast response with respect to process variations may be achieved even for a plating tool including a plurality of process chambers.

1 . A method, comprising: 
 determining sensitivity data quantitatively relating a set of currents for a multi-anode configuration of an electroplating tool to a thickness of a metal layer formed on a substrate by electroplating; and    determining an updated set of currents for said multi-anode configuration on the basis of said sensitivity data for a second substrate to be processed in said electroplating tool.    
     
     
         2 . The method of  claim 1 , further comprising obtaining thickness profile data from at least one substrate processed in said electroplating tool and determining said updated set of currents on the basis of said thickness profile data.  
     
     
         3 . The method of  claim 1 , further comprising determining a second updated set of currents for a second multi-anode configuration on the basis of said sensitivity data, wherein a sum of said updated set of currents is substantially equal to a sum of said second updated set of currents.  
     
     
         4 . The method of  claim 1 , further comprising selecting a desired thickness profile and determining said updated set of currents on the basis of said desired thickness profile.  
     
     
         5 . The method of  claim 4 , further comprising obtaining a set of reference current data from said at least one substrate and determining said updated set of currents on the basis of said reference current data.  
     
     
         6 . The method of  claim 1 , further comprising determining an allowable range for each current of said updated set of currents.  
     
     
         7 . The method of  claim 6 , wherein said updated set of currents is determined under the secondary condition that each current of said updated set is within its respective allowable range.  
     
     
         8 . The method of  claim 7 , further comprising selecting a desired amount of metal to be deposited and determining a total current value and a process time required to actually deposit said desired amount of metal on a substrate.  
     
     
         9 . The method of  claim 8 , wherein said updated set of currents is determined under the secondary condition that a sum of individual currents of said updated set is equal to said total current value.  
     
     
         10 . The method of  claim 9 , wherein said updated set of currents is determined by calculating a minimum of a difference between said thickness profile data and said desired profile.  
     
     
         11 . The method of  claim 10 , further comprising determining a position independent portion of metal thickness when calculating said minimum and using said position independent portion to determine an updated process time for said second substrate.  
     
     
         12 . The method of  claim 1 , further comprising controlling the thickness profile for a plurality of second substrates on the basis of said updated set of currents.  
     
     
         13 . The method of  claim 1 , further comprising obtaining thickness profile data from said second substrate after processing said second substrate with said updated set of currents and determining a new updated set of currents on the basis of the thickness profile data of said second substrate.  
     
     
         14 . The method of  claim 1 , wherein said electroplating tool comprises at least one further multi-anode configuration and wherein an updated set of currents is determined for said at least one further multi-anode configuration.  
     
     
         15 . The method of  claim 4 , wherein said desired thickness profile is selected on the basis of at least one process specific characteristic of a process to which said second substrate is subjected after completion of the electroplating process.  
     
     
         16 . The method of  claim 15 , wherein said at least one process specific characteristic is a removal rate distribution across a substrate of a chemical mechanical polishing process.  
     
     
         17 . The method of  claim 16 , further comprising obtaining removal rate distribution data from said second substrate after polishing said second substrate and selecting said desired thickness profile on the basis of said removal rate distribution data.  
     
     
         18 . The method of  claim 4 , wherein said desired thickness profile is selected on the basis of at least one process specific characteristic of a process to which said second substrate is subjected before said electroplating process.  
     
     
         19 . The method of  claim 18 , wherein said at least one process specific characteristic relates to sputter deposition of at least one of a barrier layer and a seed layer.  
     
     
         20 . A method of depositing metal in an electroplating tool having at least one process chamber including a multi-anode configuration, the method comprising: 
 determining a set of currents for said multi-anode configuration on the basis of a desired thickness profile, thickness profile data obtained from at least one substrate processed in said electroplating tool and a model quantitatively describing a relation between current supplied to said multi-anode configuration and a thickness profile; and    depositing metal on one or more substrates while using said determined set of currents.    
     
     
         21 . The method of  claim 20 , wherein said model is based on sensitivity data relating a thickness profile to a current variation during the deposition of metal in said electroplating tool.  
     
     
         22 . The method of  claim 20 , wherein said electroplating tool comprises at least one further process chamber including a multi-anode configuration and a further set of currents is determined, on the basis of a desired thickness profile, thickness profile data obtained from at least one substrate processed in said electroplating tool and a model quantitatively describing a relation between current supplied to said multi-anode configuration and a thickness profile, prior to processing at least one substrate in said at least one further process chamber.  
     
     
         23 . The method of  claim 20 , further comprising obtaining thickness profile data from said at least one substrate and using said obtained thickness profile data of said at least one substrate as the thickness profile data for determining said set of currents for a substrate to be processed in said electroplating tool.  
     
     
         24 . The method of  claim 20 , further comprising determining an updated plating process time for depositing metal on said one or more substrates.  
     
     
         25 . The method of  claim 24 , wherein said updated process time is determined on the basis of a previously used process time and a sensitivity factor expressing a change of a thickness of plated metal over plating time required to create said change.  
     
     
         26 . A method of controlling an electroplating tool including a plurality of process chambers having a multi-anode configuration, the method comprising: 
 calculating a set of currents for each multi-anode configuration; and    simultaneously processing a substrate in each of the plurality of process chambers with said determined sets of currents.    
     
     
         27 . The method of  claim 26 , wherein a sum of currents for each set is substantially equal to a predefined target value.  
     
     
         28 . The method of  claim 26 , further comprising: 
 determining sensitivity data quantitatively relating a set of reference currents for said multi-anode configuration to a thickness of a metal layer formed on a substrate processed in at least one of said process chambers; and    determining said sets of currents for said multi-anode configurations on the basis of said sensitivity data for a plurality of second substrates to be processed in said process chambers.    
     
     
         29 . The method of  claim 28 , further comprising obtaining thickness profile data from at least one substrate processed in said electroplating tool and determining said sets of currents on the basis of said thickness profile data.  
     
     
         30 . The method of  claim 26 , further comprising selecting a desired thickness profile and determining said sets of currents on the basis of said desired thickness profile.  
     
     
         31 . The method of  claim 28 , further comprising obtaining a set of reference current data from a plurality of substrates previously processed in said plurality of process chambers and determining said sets of currents on the basis of said reference current data.  
     
     
         32 . The method of  claim 31 , further comprising determining an allowable range for each individual current in each of said sets of currents.  
     
     
         33 . The method of  claim 32 , wherein said sets of currents are determined under the secondary condition that each current of said sets is within its respective allowable range.  
     
     
         34 . The method of  claim 33 , further comprising selecting a desired amount of metal to be deposited and determining a total current value and a process time required to actually deposit said desired amount of metal on a substrate.  
     
     
         35 . A controller for an electroplating tool, comprising: 
 a calculation unit configured to determine, for a substrate to be processed in said electroplating tool, a set of currents for at least one multi-anode configuration on the basis of a desired thickness profile.    
     
     
         36 . The controller of  claim 35 , wherein said calculation unit is configured to determine a plurality of sets of currents for a plurality of multi-anode configurations prior to processing a substrate in each of the plurality of multi-anode configurations.