Patent ID: 8234013

Claim:
A semiconductor manufacturing system comprising: a processing tank containing a processing liquid for processing a semiconductor substrate; a preprocessing tank preprocessing the processing liquid; first piping transferring the processing liquid contained in the processing tank to the preprocessing tank; second piping returning the processing liquid preprocessed in the preprocessing tank to the processing tank; a first valve provided on the first piping; a waste liquid tank collecting the processing liquid that has become a waste liquid; a second valve provided downstream of the first valve on the first piping; third piping coupling a portion of the first piping in a position between the first and second valves and the waste liquid tank; a third valve provided on the third piping; a first control unit opening the first valve in preprocessing tank introduction mode in which the processing liquid contained in the processing tank is introduced into the preprocessing tank; and a second control unit controlling the second and third valves, wherein if the processing liquid contained in the processing tank is collected into the waste liquid tank, the second control unit closes the second valve and opens the third valve, and outputs, to the first control unit, a preprocessing tank introduction shift signal for instructing a shift to the preprocessing tank introduction mode; and upon receipt of the preprocessing tank introduction shift signal from the second control unit, the first control unit opens the first valve.