Method for changing concentration of treatment solution and treatment solution supply apparatus

Abstract

According to the present invention, in changing the concentration of a treatment solution supplied to a substrate, a volume of an existing treatment solution in a tank connected to a treatment solution supply section for supplying the treatment solution to the substrate is first measured. Based on this measured value, a minimum drain volume of the existing treatment solution to be drained out from the tank and a supply volume of either a treatment solution with a predetermined concentration or a diluting fluid to be supplied into the tank is calculated respectively in order to change the treatment solution in the tank to be in an intended volume and to have an intended concentration. Then, the calculated drain volume of the existing treatment solution is drained out from the tank. Meanwhile, the calculated supply volume of either the treatment solution with the predetermined concentration or the diluting fluid is supplied into the tank. According to the present invention, since the drain volume in changing the concentration of the treatment solution can be reduced, a wasteful consumption volume of the treatment solution is reduced accordingly so that cost reduction can be realized. Moreover, the time required for the concentration change can be shortened.

1 . A method for changing a concentration of a treatment solution supplied to a substrate, comprising the steps of: 
 measuring a volume of an existing treatment solution in a tank connected to a treatment solution supply section for supplying the treatment solution to the substrate;    calculating, based on a value measured in said measuring step, a minimum drain volume of the existing treatment solution to be drained out from the tank and a supply volume of either a treatment solution with a predetermined concentration or a diluting fluid to be supplied into the tank respectively in order to change the treatment solution in the tank to be in an intended volume and to have an intended concentration;    draining out the calculated drain volume of the existing treatment solution from the tank; and    supplying the calculated supply volume of either the treatment solution with the predetermined concentration or the diluting fluid into the tank.    
     
     
         2 . A method for changing a concentration of a treatment solution according to  claim 1 , further comprising the step of: 
 measuring the concentration of the treatment solution in the tank after the calculated supply volume of either the treatment solution with the predetermined concentration or the diluting fluid is supplied into the tank, and supplying the treatment solution with the predetermined concentration or the diluting fluid into the tank again based on the measured concentration.    
     
     
         3 . A method for changing a concentration of a treatment solution according to  claim 1 , further comprising the step of: 
 returning to the tank the existing treatment solution remaining in a pipe connecting the tank and the treatment solution supply section before the volume of the existing treatment solution in the tank is measured.    
     
     
         4 . A method for changing a concentration of a treatment solution according to  claim 1 , further comprising the step of: 
 performing a test discharge of the treatment solution from the treatment solution supply section until a concentration of the treatment solution supplied from the treatment solution supply section reaches the predetermined concentration.    
     
     
         5 . A method for changing a concentration of a treatment solution according to  claim 4 , 
 wherein, in a case when the treatment solution with the predetermined concentration is supplied into the tank, the treatment solution with the predetermined concentration is supplied into the pipe connecting the tank and the treatment solution supply section and the test discharge of the treatment solution is performed from the treatment solution supply section, and    wherein, in a case when the diluting fluid is supplied into the tank, the diluting fluid is supplied into the pipe and the test discharge of the treatment solution is performed from the treatment solution supply section.    
     
     
         6 . A method for changing a concentration of a treatment solution according to  claim 4 , 
 wherein a concentration of the treatment solution of which the test discharge is performed is measured.    
     
     
         7 . A method for changing a concentration of a treatment solution according to  claim 1 , further comprising the step of: 
 draining out the existing treatment solution remaining in the pipe which connects the tank and the treatment solution supply section.