| 摘要 |
PROBLEM TO BE SOLVED: To provide a substrate processing apparatus capable of precisely measuring a silicon concentration in a phosphoric acid solution.SOLUTION: A substrate processing apparatus includes: a circulation line 3 which includes a processing tank 11 reserving a phosphoric acid solution, a circulation pump 13 sending the phosphoric acid solution, a heater 15 for circulation heating the phosphoric acid solution, and a filter 17 filtering the phosphoric acid solution, supplies the phosphoric acid solution discharged from the processing tank 11 in the order of the circulation pump 13, heater 15 for circulation, and filter 17, and returns the phosphoric acid solution from the filter 17 to the processing tank 11; a branch pipe 31 which branches off from the circulation line 3 between the heater 15 for circulation and filter 17, and extracts the phosphoric acid solution from the circulation line 3; and a concentration measuring section 51 which is connected to communicate with the branch pipe 31, and measures the silicon concentration in the phosphoric acid solution by a potential difference measuring method. |
