Polishing material supply system and related methods

Abstract

A method is provided. The method includes: determining a forecasted slurry consumption value; determining a refill line associated with the forecasted slurry consumption value; determining a mix-in volume associated with the forecasted slurry consumption value; and operating a supply tank containing polishing slurry, the operating being according to the refill line and the mix-in volume. The operating includes: determining whether liquid level of the polishing slurry is below the refill line by a continuous liquid level sensor assembly mounted on the supply tank; in response to the liquid level of the polishing slurry being below the refill line, adding the mix-in volume of fresh polishing slurry to the supply tank; and supplying the polishing slurry to a polishing apparatus that is operable to polish a surface of a semiconductor wafer.

What is claimed is: 
     
         1 . A method, comprising:
 determining a forecasted slurry consumption value;   determining a refill line associated with the forecasted slurry consumption value;   determining a mix-in volume associated with the forecasted slurry consumption value; and   operating a supply tank containing polishing slurry, the operating being according to the refill line and the mix-in volume, the operating including:
 determining whether liquid level of the polishing slurry is below the refill line by a continuous liquid level sensor assembly mounted on the supply tank; 
 in response to the liquid level of the polishing slurry being below the refill line, adding the mix-in volume of fresh polishing slurry to the supply tank; and 
 supplying the polishing slurry to a polishing apparatus that is operable to polish a surface of a semiconductor wafer. 
   
     
     
         2 . The method of  claim 1 , comprising:
 prior to determining the forecasted slurry consumption value, operating the supply tank according to a first refill line and a first mix-in volume; and   prior to operating the supply tank according to the refill line and the mix-in volume:
 replacing the first refill line with the refill line; and 
 replacing the first mix-in volume with the mix-in volume. 
   
     
     
         3 . The method of  claim 2 , wherein replacing the first refill line includes replacing the first refill line with the refill line that exceeds the first refill line in response to an increase in volume of wafers forecasted to be polished by the polishing apparatus. 
     
     
         4 . The method of  claim 2 , wherein replacing the first mix-in volume includes replacing the first mix-in volume with the mix-in volume that is less than the first mix-in volume in response to a decrease in volume of wafers forecasted to be polished by the polishing apparatus. 
     
     
         5 . The method of  claim 1 , wherein determining the forecasted slurry consumption value includes determining the forecasted slurry consumption value based on a conductivity of the polishing slurry contained in the supply tank. 
     
     
         6 . The method of  claim 1 , wherein determining the forecasted slurry consumption value includes determining the forecasted slurry consumption value based on a rate of increase of conductivity of the polishing slurry contained in the supply tank. 
     
     
         7 . The method of  claim 1 , wherein determining the forecasted slurry consumption value includes determining the forecasted slurry consumption value based on a supply lifetime of the polishing slurry contained in the supply tank. 
     
     
         8 . A method comprising:
 determining a liquid level of polishing slurry contained in a supply tank via a liquid level sensor assembly mounted to the supply tank, the liquid level sensor assembly extending continuously from a first end of the supply tank to a second end of the supply tank;   determining whether the liquid level is below a refill line;   in response to the liquid level being below the refill line, forming mixed polishing slurry by adding a mix-in volume of fresh polishing slurry to the supply tank;   forming second polishing slurry by aging the mixed polishing slurry; and   polishing a surface of a semiconductor wafer using the second polishing slurry by a polishing apparatus.   
     
     
         9 . The method of  claim 8 , comprising:
 determining the refill line and the mix-in volume via a trained machine learning model.   
     
     
         10 . The method of  claim 9 , comprising:
 generating the trained machine learning model by training a machine learning model using polishing liquid historical data and labeled data associated with the polishing liquid historical data.   
     
     
         11 . The method of  claim 10 , comprising:
 generating the trained machine learning model by training a machine learning model using tool historical data, wafer production historical data and labeled data associated with the tool historical data and the wafer production historical data.   
     
     
         12 . The method of  claim 10 , wherein training the machine learning model includes:
 training the machine learning model using polishing slurry conductivity historical data.   
     
     
         13 . The method of  claim 9 , wherein determining the refill line and the mix-in volume includes determining the refill line and the mix-in volume via the trained machine learning model based on at least one of polishing slurry conductivity data, polishing slurry rate of increase data or supply lifetime data. 
     
     
         14 . The method of  claim 9 , wherein determining the refill line and the mix-in volume includes determining the refill line and the mix-in volume via the trained machine learning model based on at least one of number of polishing apparatuses supplied by the supply tank or production volume of each of a plurality of polishing apparatuses supplied by the supply tank. 
     
     
         15 . A system, comprising:
 a first tank operable to store base slurry;   a second tank operable to generate polishing slurry including filtered base slurry generated from the base slurry;   a third tank operable to supply the polishing slurry to a polishing apparatus;   a liquid level sensor assembly mounted to the third tank, the liquid level sensor assembly extending continuously from a first end of the third tank to a second end of the third tank; and   a controller in data communication with the liquid level sensor assembly, the controller operable to:
 replace a first refill line associated with the liquid level sensor assembly with a second refill line that is at a different liquid level than the first refill line; 
 determine whether a liquid level of the polishing slurry in the third tank is below the second refill line; and 
 in response to the liquid level being below the second refill line, add fresh polishing slurry to the third tank. 
   
     
     
         16 . The system of  claim 15 , wherein the controller is operable to:
 generate second polishing slurry by aging a mixture of the polishing slurry and the fresh polishing slurry in the third tank; and   supply the second polishing slurry to the polishing apparatus via the third tank.   
     
     
         17 . The system of  claim 15 , wherein the liquid level sensor assembly includes a plurality of capacitive liquid level sensors arranged between the first end and the second end. 
     
     
         18 . The system of  claim 17 , wherein resolution of the liquid level sensor assembly is in a range of about 1% to about 20%. 
     
     
         19 . The system of  claim 17 , wherein resolution of the liquid level sensor assembly is finer than about 5%. 
     
     
         20 . The system of  claim 15 , wherein the controller is operable to:
 receive the second refill line generated by a trained machine learning model.