Plating system and method for management of plating solution using plating system

Abstract

In a plating system, a plating consumption coefficient per unit number of substrates subjected to a treatment is calibrated once every predetermined time interval, and a replenishing amount in response to consumption of an additive associated with a plating treatment is computed by use of a formula defined as “the plating consumption coefficient×the number of substrates subjected to the plating treatment” and the replenishing amount of the additive is replenished. Accordingly, an amount of consumption of the additive coincides with the replenishing amount thereof. As a result, a concentration of the additive contained in a plating solution can be maintained at a constant concentration.

What is claimed is:  
     
         1 . A plating system comprising: 
 a plating cell for providing a substrate with a plating treatment;    a plating solution tank having a function to supply and collect a plating solution while continuously circulating said plating solution between said plating cell and said plating solution tank;    a plating solution analyzation machine for measuring a concentration of an additive contained in said plating solution inside said plating solution tank and thereby computing a replenishing amount of said additive into said plating solution tank; and    an additive replenishing apparatus for replenishing said additive into said plating solution tank depending on said replenishing amount of said additive into said plating solution tank,    wherein said plating solution analyzation machine measures said concentration of said additive contained in said plating solution inside said plating solution tank once every predetermined time period and then computes a value by dividing an amount of said additive consumed in said plating treatment performed in the predetermined time period by the number of substrates subjected to said plating treatment so as to define a plating treatment additive consumption coefficient,    said plating solution analyzation machine computes a plating-dependent consumption amount predictive value of said additive by multiplying said plating treatment additive consumption coefficient at every monitoring time period which is shorter than the predetermined time period by the number of substrates subjected to said plating treatment in said monitoring time period, and then defines an additive consumption predictive value by adding said plating-dependent consumption predictive value to an elapsed time-dependent consumption amount of said additive,    said plating solution analyzation machine finds said additive concentration on a recent monitoring occasion based on said additive concentration on an immediately preceding monitoring occasion and said additive consumption predictive value, and    said additive replenishing apparatus replenishes said replenishing amount of said additive into said plating solution tank if said replenishing amount, which is obtained by multiplying a value defined as subtraction of said additive concentration on said recent monitoring occasion from a target concentration of said additive by an amount of said plating solution, reaches a predetermined critical value or more.    
     
     
         2 . The plating system according to  claim 1 , wherein said elapsed time-dependent consumption amount of said additive is computed by multiplying said monitoring time period by an additive concentration variation coefficient per unit time having a constant value.  
     
     
         3 . The plating system according to  claim 1 , 
 wherein said plating solution is a copper-plating solution, and    said additive is a thiol-based organic additive.    
     
     
         4 . A method, using a plating system, for management of a plating solution, said plating system including: 
 a plating cell for providing a substrate with a plating treatment;    a plating solution tank having a function to supply and collect said plating solution while continuously circulating said plating solution between said plating cell and said plating solution tank;    a plating solution analyzation machine for measuring a concentration of an additive contained in said plating solution inside said plating solution tank and thereby computing a replenishing amount of said additive into said plating solution tank; and    an additive replenishing apparatus for replenishing said additive into said plating solution tank depending on said replenishing amount of said additive into said plating solution tank,    said method comprising the steps of: 
 allowing said plating solution analyzation machine to measure said concentration of said additive contained in said plating solution inside said plating solution tank once every predetermined time period and then computing a value by dividing an amount of said additive consumed in said plating treatment performed in the predetermined time period by the number of substrates subjected to said plating treatment so as to define a plating treatment additive consumption coefficient;  
 allowing said plating solution analyzation machine to compute a plating-dependent consumption amount predictive value of said additive by multiplying said plating treatment additive consumption coefficient at every monitoring time period which is shorter than the predetermined time period by the number of substrates subjected to said plating treatment in said monitoring time period, and then defining an additive consumption predictive value by adding said plating-dependent consumption predictive value to an elapsed time-dependent consumption amount of said additive;  
 allowing said plating solution analyzation machine to define an additive concentration based on said additive concentration on an immediately preceding monitoring occasion and said additive consumption predictive value; and  
 allowing said additive replenishing apparatus to replenish a predetermined amount of said additive into said plating solution tank if said replenishing amount, which is obtained by multiplying a value defined as subtraction of said additive concentration on said recent monitoring occasion from a target concentration of said additive by an amount of said plating solution, reaches a predetermined critical value or more.  
   
     
     
         5 . The method for management of a plating solution according to  claim 4 , wherein said elapsed time-dependent consumption amount of said additive is computed by multiplying said monitoring time period by an additive concentration variation coefficient per unit time having a constant value.  
     
     
         6 . The method for management of a plating solution according to  claim 4 , 
 wherein said plating treatment additive consumption coefficient is an amount of said additive consumed for one substrate to be subjected to said plating treatment, in the step of measuring said concentration of said additive contained in said plating solution inside said plating solution tank once every predetermined time period and then computing a value by dividing said amount of said additive consumed in said plating treatment performed in the predetermined time period by the number of substrates subjected to said plating treatment so as to define a plating treatment additive consumption coefficient, and    said one substrate corresponds to a value obtained by converting an actual substrate area into a standardized unit based on a substrate having a certain area.    
     
     
         7 . The method for management of a plating solution according to  claim 4 , 
 wherein said plating solution is a copper-plating solution, and    said additive is a thiol-based organic additive.    
     
     
         8 . The method for management of a plating solution according to  claim 4 , wherein said plating treatment performed by immersing said substrate in said plating cell of said plating system is a plating treatment to form a plurality of types of plating films with different film thicknesses on said substrate.