Method and apparatus for monitoring, dosing and distribution of chemical solutions

Abstract

It is an object of the present invention to provide a system and method for monitoring, dosing and distribution of a chemical composition in a material treatment process, the chemical composition containing at least one additive for maintaining quality of the chemical treatment process. The system and method include: at least one chemical containing unit configured to contain the chemical composition for the chemical treatment process; a dosing unit fluidly communicating with the at least one chemical containing unit configured to receive the chemical composition therefrom and to add a selected dose of the at least one additive to the chemical composition therein; an online monitor configured to monitor a property of the chemical composition at the dosing unit and to transmit a signal corresponding to the monitored property; and a controller programmed and configured to receive the signal from the online monitor and send a signal to the dosing system to add the selected dose to the chemical composition therein in response to the monitored property.

1 . A system for monitoring, dosing and distribution of a chemical composition in a material treatment process, the chemical composition containing at least one additive for maintaining quality of the chemical treatment process, said system comprising: 
 at least one chemical containing unit configured to contain the chemical composition for the chemical treatment process;    a dosing unit fluidly communicating with said at least one chemical containing unit configured to receive the chemical composition therefrom and to add a selected dose of the at least one additive to the chemical composition therein;    a online monitor configured to monitor a property of the chemical composition at said dosing unit and to transmit a signal corresponding to the monitored property; and    a controller programmed and configured to receive the signal from said online monitor and send a signal to said dosing unit to add the selected dose to the chemical composition therein in response to the monitored property.    
     
     
         2 . The system of  claim 1 , wherein the controller comprises a processor programmed with an algorithm such that the processor: 
 determines a rate of depletion over a depletion time period of at least one of the at least one additive in the chemical composition based upon a concentration of the at least one of the at least one additive measured by said monitor in comparison to a concentration of the at least one of the at least one additive which was last measured by said monitor;    predicts an amount of the at least one of the at least one additive that when added to the chemical composition will maintain a concentration of the additive within a predetermined concentration range around a predetermined setpoint concentration; and    corrects the predicted amount by adding to, or subtracting from, the predicted amount, an amount of the at least one additive based upon a previous measurement by said monitor of the concentration of the at least one additive, wherein the corrected amount is the selected dose.    
     
     
         3 . The system of  claim 1 , wherein said at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         4 . The system of  claim 2 , wherein said at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         5 . The system of  claim 1 , further comprising: 
 a chemical delivery unit in fluid communication with said at least one chemical containing unit and said dosing unit and configured to deliver the chemical composition to said at least one chemical containing unit    
     
     
         6 . The system of  claim 5 , further comprising: 
 a first valve arrangement in fluid communication with said chemical containing unit and said dosing unit, said first valve arrangement configured to allow or prevent a flow of the chemical composition from said chemical containing unit to said dosing unit; and    a second valve arrangement in fluid communication with said chemical containing unit and said chemical delivery unit, said second valve arrangement configured to allow or prevent a flow of the chemical composition from said chemical containing unit to said chemical delivery unit.    
     
     
         7 . The system of  claim 6 , wherein said controller comprises a processor programmed with an algorithm such that it: 
 determines whether said system should operate in a main recirculation mode in which said first valve arrangement allows a flow of the chemical composition from said at least one chemical containing unit to said dosing unit and said second valve arrangement prevents a flow of the chemical composition from said at least one chemical containing unit to said dosing unit, or in a dosing mode in which said first valve arrangement prevents a flow of the chemical composition from said chemical containing unit to said dosing unit and allows a flow of the chemical composition from said at least one chemical containing unit to said chemical delivery unit.    
     
     
         8 . The system of  claim 7 , wherein in response to said algorithm determining that the system should operate in the main recirculation mode, said controller i) sends a signal to either open said first valve arrangement or to allow said first valve arrangement to remain open so that a flow of the chemical composition is allowed from said at least one chemical containing unit to said dosing unit, and ii) sends a signal either to close said second valve arrangement or to allow said second valve arrangement to remain open so that a flow of the chemical composition is prevented from said at least one chemical containing unit to said dosing unit.  
     
     
         9 . The system of  claim 8 , wherein said dosing unit comprises: 
 a dosing unit reservoir configured to receive a flow of the chemical composition from said at least one chemical containing unit and direct a flow of the chemical composition from said dosing unit to said chemical delivery unit; and    a dosage element configured to receive a flow of the chemical composition from said dosing unit reservoir and direct a flow of the chemical composition to said dosing unit reservoir, said dosage element also configured to add the selected dose to the chemical composition, wherein in response to said algorithm determining that the system should operate in the dosing mode, said controller i) sends a signal to and actuates said first valve arrangement to prevent a flow of the chemical composition from said at least one chemical containing unit to said dosing unit, and sends a signal to and actuates said second valve arrangement to allow a flow of the chemical composition from said at least one chemical containing unit to said chemical delivery unit.    
     
     
         10 . The system of  claim 9 , wherein: 
 said first valve arrangement comprises a first valve, a first conduit in fluid communication with and extending from said chemical containing unit to said first valve, and a second conduit in fluid communication with and extending from said first valve to said dosing unit, said first valve disposed intermediate said first and second conduits, wherein an open position of said first valve allows a flow of the chemical composition from said first conduit to said second conduit and a closed position of said first valve prevents a flow of the chemical composition from said first conduit to said second conduit;    said second valve arrangement comprises a second valve, a third conduit in fluid communication with and extending from said first conduit to said second valve, and a fourth conduit in fluid communication with and extending from said second valve to said chemical delivery unit, said second valve disposed intermediate said third and fourth conduits, wherein an open position of said second valve allows a flow of the chemical composition from said first conduit to said fourth conduit via said third conduit and a closed position of said second valve prevents a flow of the chemical composition from said third conduit to said fourth conduit.    
     
     
         11 . The system of  claim 10 , wherein said at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         12 . The system of  claim 5 , wherein wherein said at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         13 . The system of  claim 1 , wherein said at least one chemical containing unit comprises at least two chemical containing units.  
     
     
         14 . The system of  claim 13 , further comprising: 
 a plurality of chemical containing unit outlets, said plurality equal to the number of said at least two chemical containing units, wherein each of said chemical containing unit outlets is associated with a respective one of said at least two chemical containing units;    a chemical containing unit outlet manifold in fluid communication with said plurality of chemical containing unit outlets;    a chemical containing element outlet reservoir in fluid communication with said chemical containing unit outlet manifold and said dosing unit.    
     
     
         15 . The system of  claim 14 , wherein wherein said at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         16 . A method for monitoring, dosing and distribution of a chemical composition in a chemical treatment process, the chemical composition containing at least one additive for maintaining quality of the chemical treatment process, comprising the steps of: 
 a) allowing the chemical composition to flow from at least one chemical containing unit to a dosing unit;    b) monitoring a property of the chemical composition with an online monitor at a location intermediate the chemical containing unit and the dosing unit or at the dosing unit;    c) sending from the online monitor to a controller a signal associated with the monitored property;    d) determining at the controller whether the at least one additive should be added to the chemical composition at the reservoir based upon the monitored property, thereby resulting in a decision to add or not a selected amount of the at least one additive to the chemical composition at the reservoir based upon the signal from the online monitor;    e) sending from the controller to the dosing unit a signal associated with the decision;    f) allowing the selected amount of the at least one additive to be added or not be added to the chemical composition at the dosing unit in response to the signal associated with the decision;    g) allowing the chemical composition to flow from the dosing unit to the chemical containing unit.    
     
     
         17 . The method of  claim 1 , further comprising the steps of: 
 determining by the controller a rate of depletion over a depletion time period of at least one of the at least one additive in the chemical composition based upon a concentration of the at least one of the at least one additive measured by said monitor in comparison to a concentration of the at least one of the at least one additive previously measured by said monitor;    predicting by the controller an amount of at least one of the at least one additive that when added to the chemical composition will maintain a concentration of the additive within a predetermined concentration range around a predetermined setpoint concentration; and    correcting by the controller the predicted amount by adding to, or subtracting from, the predicted amount, an amount of the at least one additive based upon a previous concentration of the at least one additive measured by said monitor, wherein the corrected amount is the selected dose.    
     
     
         18 . The system of  claim 17 , wherein the at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         19 . The system of  claim 16 , wherein the at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         20 . The system of  claim 16 , wherein said step of allowing the chemical composition to flow from the dosing unit to the at least one chemical containing unit comprises: 
 allowing the chemical composition to flow from the dosing unit to a chemical delivery unit; and    delivering the chemical composition from the at least one chemical delivery unit to the chemical containing unit.    
     
     
         21 . The system of  claim 20 , further comprising the steps of: 
 providing a first valve arrangement in fluid communication with the chemical containing unit and the dosing unit, the first valve arrangement configured to allow or prevent a flow of the chemical composition from the chemical containing unit to the dosing unit; and    providing a second valve arrangement in fluid communication with the chemical containing unit and the chemical delivery unit, the second valve arrangement configured to allow or prevent a flow of the chemical composition from the chemical containing unit to the chemical delivery unit.    
     
     
         22 . The system of  claim 21 , further comprising the step of: 
 determining by the controller whether to perform said method in a main recirculation mode in which the first valve arrangement allows a flow of the chemical composition from the at least one chemical containing unit to the dosing unit and the second valve arrangement prevents a flow of the chemical composition from the at least one chemical containing unit to the dosing unit, or in a dosing mode in which the first valve arrangement prevents a flow of the chemical composition from the chemical containing unit to the dosing unit and allows a flow of the chemical composition from the at least one chemical containing unit to the chemical delivery unit, thereby resulting in a mode decision.    
     
     
         23 . The system of  claim 22 , further comprising the step of: 
 in response to the processor determining that said method should be performed in the main recirculation mode, sending a signal to either open said first valve arrangement or to allow said first valve arrangement to remain open so that a flow of the chemical composition is allowed from said at least one chemical containing unit to said dosing unit.    
     
     
         24 . The system of  claim 22 , further comprising the step of: 
 in response to the processor determining that said method should be performed in the dosing mode, i) sending a signal either to close the first valve arrangement or to allow the first valve arrangement to remain closed so that a flow of the chemical composition is prevented from the at least one chemical containing unit to the dosing unit, and ii) sending a signal either to open the second valve arrangement or to allow the second valve arrangement to remain open so that a flow of the chemical composition is allowed from the at least one chemical containing unit to the chemical delivery unit.    
     
     
         25 . The method of  claim 24 , further comprising the steps of: 
 providing the dosing unit with a reservoir and a dosage element;    sending by the controller a signal to the dosage element to add the selected amount to a flow of the chemical composition from the dosing unit reservoir;    adding by the dosage element the selected amount to the flow of chemical composition from the dosing unit reservoir; and    allowing the combined flow of the selected amount of the at least one additive and the chemical composition to flow from the dosage element to the dosing unit reservoir.    
     
     
         26 . The method of  claim 17 , wherein said at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         27 . The method of  claim 23 , wherein said at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         28 . The method of  claim 24 , wherein said at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         29 . The method of  claim 16 , wherein said at least one chemical containing unit comprises at least two chemical containing units.  
     
     
         30 . The method of  claim 29 , comprising the further steps of: 
 providing a plurality of chemical containing unit outlets, the plurality being equal to the number of the at least two chemical containing units, wherein each of the chemical containing unit outlets is associated with a respective one of the at least two chemical containing units;    providing a chemical containing unit outlet manifold in fluid communication with the plurality of chemical containing unit outlets;    providing a chemical containing unit outlet reservoir in fluid communication with the chemical containing unit outlet manifold and the dosing unit;    allowing a flow of the chemical composition from the plurality of chemical containing unit outlets to the chemical containing unit outlet reservoir; and    allowing a flow of the chemical composition from the chemical containing unit outlet reservoir to the dosing unit.    
     
     
         31 . The method of  claim 30 , wherein said at least one chemical containing unit is an electroplating bath of a wafer electroplating tool.  
     
     
         32 . The system of  claim 2 , wherein the processor is programmed with the algorithm such that the amount added to or subtracted from the predicted amount is based upon at least two previous measurements by said monitor of the concentration of the at least one additive.  
     
     
         33 . The system of  claim 2 , wherein the processor is programmed with the algorithm such that a time in between additions of the at least one additive is less than the time in between measurements by said monitor.  
     
     
         34 . The system of  claim 34 , wherein the processor is programmed with the algorithm such that a frequency of additions of the at least one additive by said dosing unit may be varied.  
     
     
         35 . The system of  claim 2 , wherein the processor is programmed with the algorithm such that the predicted amount is also based upon a derivative of the depletion rate.  
     
     
         36 . The system of  claim 2 , wherein the processor is programmed with the algorithm such that the predicted amount does not depend upon a variable condition at said chemical containing unit.  
     
     
         37 . The system of  claim 2 , wherein the processor is programmed with the algorithm such that the predicted amount does not depend upon a time interval between successive measurements by said monitor.  
     
     
         38 . The method of  claim 17 , wherein the amount added to or substracted from the predicted amount is based upon at least two previous measurements by the monitor of the concentration of the at least one additive.  
     
     
         39 . The method of  claim 17 , further comprising the step of: 
 varying a time interval between additions of the at least one additive such that the time in between additions is less than a time interval between measurements by said monitor.    
     
     
         40 . The method of  claim 39 , further comprising the step of: 
 varying a frequency of additions of the at least one additive by said dosing unit.    
     
     
         41 . The method of  claim 17 , wherein the predicted amount is also based upon a derivative of the depletion rate.  
     
     
         42 . The method of  claim 17 , wherein the predicted amount does not depend upon a variable condition at said chemical containing unit.