Substrate treating apparatus

Abstract

A substrate treating apparatus includes a circulating line having a treating tank for storing a phosphoric acid aqueous solution, a circulating pump for feeding the phosphoric acid aqueous solution, a heater for circulation for heating the phosphoric acid aqueous solution, a filter for filtering the phosphoric acid aqueous solution, the circulating line causing the phosphoric acid aqueous solution discharged from the treating tank to flow in order of the circulating pump, the heater for circulation and the filter, and returning the phosphoric acid aqueous solution from the filter to the treating tank. The apparatus also includes a branch pipe branching from the circulating line between the heater for circulation and the filter for extracting the phosphoric acid aqueous solution from the circulating line, and a concentration measuring station connected to the branch pipe for measuring silicon concentration in the phosphoric acid aqueous solution by potentiometry.

What is claimed is: 
     
         1 . A substrate treating apparatus comprising:
 a circulating line including a treating tank for storing a phosphoric acid aqueous solution, a circulating pump for feeding the phosphoric acid aqueous solution, a heater for circulation for heating the phosphoric acid aqueous solution, a filter for filtering the phosphoric acid aqueous solution, the circulating line causing the phosphoric acid aqueous solution discharged from the treating tank to flow in order of the circulating pump, the heater for circulation and the filter, and returning the phosphoric acid aqueous solution from the filter to the treating tank;   a branch pipe branching from the circulating line between the heater for circulation and the filter for extracting the phosphoric acid aqueous solution from the circulating line; and   a concentration measuring station connected to the branch pipe for measuring silicon concentration in the phosphoric acid aqueous solution by potentiometry.   
     
     
         2 . The substrate treating apparatus according to  claim 1  further comprising a heater for sampling for heating the phosphoric acid aqueous solution extracted from the circulating line. 
     
     
         3 . The substrate treating apparatus according to  claim 2  wherein the heater for sampling is mounted on the branch pipe for heating the phosphoric acid aqueous solution in the branch pipe. 
     
     
         4 . The substrate treating apparatus according to  claim 2  wherein the heater for sampling is attached to the concentration measuring station for heating the phosphoric acid aqueous solution or a solution including the phosphoric acid aqueous solution in the concentration measuring station. 
     
     
         5 . The substrate treating apparatus according to  claim 2  further comprising a quantity measuring station connected to the branch pipe for measuring a predetermined quantity of the phosphoric acid aqueous solution;
 wherein the concentration measuring station is arranged to measure silicon concentration in the phosphoric acid aqueous solution measured by the quantity measuring station, and 
 the heater for sampling is attached to the quantity measuring station for heating the phosphoric acid aqueous solution in the quantity measuring station. 
 
     
     
         6 . The substrate treating apparatus according to  claim 5  wherein the quantity measuring station includes a measuring tank for storing the predetermined quantity of the phosphoric acid aqueous solution. 
     
     
         7 . The substrate treating apparatus according to  claim 5  wherein the quantity measuring station includes:
 a syringe having a cylindrical shape: 
 a plunger slidable inside the syringe in an airtight condition; and 
 a driver for driving the plunger to draw into and discharge from the syringe the predetermined quantity of the phosphoric acid aqueous solution. 
 
     
     
         8 . The substrate treating apparatus according to  claim 1  further comprising a quantity measuring station connected to the branch pipe for measuring a predetermined quantity of the phosphoric acid aqueous solution;
 wherein the concentration measuring station is arranged to measure silicon concentration in the phosphoric acid aqueous solution measured by the quantity measuring station. 
 
     
     
         9 . The substrate treating apparatus according to  claim 8  wherein the quantity measuring station includes a measuring tank for storing the predetermined quantity of the phosphoric acid aqueous solution. 
     
     
         10 . The substrate treating apparatus according to  claim 8  wherein the quantity measuring station includes:
 a syringe having a cylindrical shape; 
 a plunger slidable inside the syringe in an airtight condition; and 
 a driver for driving the plunger to draw into and discharge from the syringe the predetermined quantity of the phosphoric acid aqueous solution. 
 
     
     
         11 . The substrate treating apparatus according to  claim 1  wherein:
 the treating tank includes:
 an inner tank for immersing substrates in the phosphoric acid aqueous solution stored therein; and 
 an outer tank for collecting the phosphoric acid aqueous solution overflowing from the inner tank; 
 
 the filter includes a filter element formed between an entrance portion and an exit portion thereof; and 
 the circulating line includes:
 a first piping connecting the exit portion of the filter and the inner tank; and 
 a second piping connecting the entrance portion of the filter and the outer tank; 
 
 the branch pipe branching from the second piping. 
 
     
     
         12 . A substrate treating apparatus comprising:
 a circulating line including a treating tank for storing a phosphoric acid aqueous solution, a circulating pump for feeding the phosphoric acid aqueous solution, a heater for circulation for heating the phosphoric acid aqueous solution, a filter for filtering the phosphoric acid aqueous solution, the circulating line causing the phosphoric acid aqueous solution discharged from the treating tank to flow in order of the circulating pump, the heater for circulation and the filter, and returning the phosphoric acid aqueous solution from the filter to the treating tank;   a branch pipe branching from the circulating line for extracting the phosphoric acid aqueous solution from the circulating line;   a concentration measuring station connected to the branch pipe for measuring, by potentiometry, silicon concentration in the phosphoric acid aqueous solution extracted; and   a heater for sampling for heating the phosphoric acid aqueous solution drawn from the circulating line.   
     
     
         13 . The substrate treating apparatus according to  claim 12  wherein the heater for sampling is mounted on the branch pipe for heating the phosphoric acid aqueous solution in the branch pipe. 
     
     
         14 . The substrate treating apparatus according to  claim 12  wherein the heater for sampling is attached to the concentration measuring station for heating the phosphoric acid aqueous solution or a solution including the phosphoric acid aqueous solution in the concentration measuring station. 
     
     
         15 . The substrate treating apparatus according to  claim 12  further comprising a quantity measuring station connected to the branch pipe for measuring a predetermined quantity of the phosphoric acid aqueous solution;
 wherein the concentration measuring station is arranged to measure silicon concentration in the phosphoric acid aqueous solution measured by the quantity measuring station, and 
 the heater for sampling is attached to the quantity measuring station for heating the phosphoric acid aqueous solution in the quantity measuring station. 
 
     
     
         16 . The substrate treating apparatus according to  claim 15  wherein the quantity measuring station includes a measuring tank for storing the predetermined quantity of the phosphoric acid aqueous solution. 
     
     
         17 . The substrate treating apparatus according to  claim 15  wherein the quantity measuring station includes:
 a syringe having a cylindrical shape; 
 a plunger slidable inside the syringe in an airtight condition; and 
 a driver for driving the plunger to draw into and discharge from the syringe the predetermined quantity of the phosphoric acid aqueous solution. 
 
     
     
         18 . The substrate treating apparatus according to  claim 12  further comprising a quantity measuring station connected to the branch pipe for measuring a predetermined quantity of the phosphoric acid aqueous solution;
 wherein the concentration measuring station is arranged to measure silicon concentration in the phosphoric acid aqueous solution measured by the quantity measuring station. 
 
     
     
         19 . The substrate treating apparatus according to  claim 18  wherein the quantity measuring station includes a measuring tank for storing the predetermined quantity of the phosphoric acid aqueous solution. 
     
     
         20 . The substrate treating apparatus according to  claim 18  wherein the quantity measuring station includes:
 a syringe having a cylindrical shape: 
 a plunger slidable inside the syringe in an airtight condition; and 
 a driver for driving the plunger to draw into and discharge from the syringe the predetermined quantity of the phosphoric acid aqueous solution. 
 
     
     
         21 . The substrate treating apparatus according to  claim 12  wherein:
 the treating tank includes:
 an inner tank for immersing substrates in the phosphoric acid aqueous solution stored therein; and 
 an outer tank for collecting the phosphoric acid aqueous solution overflowing from the inner tank; 
 
 the filter includes a filter element formed between an entrance portion and an exit portion thereof; and 
 the circulating line includes:
 a first piping connecting the exit portion of the filter and the inner tank; and 
 a second piping connecting the entrance portion of the filter and the outer tank; 
 
 the branch pipe branching from the second piping.