Patent ID: 8746259

Claim:
A substrate processing apparatus comprising: a processing unit that processes a substrate; a processing solution supply unit that supplies a processing solution to the processing unit; a first chemical solution supply unit that supplies a first chemical solution to the processing unit; a second chemical solution supply unit that supplies a second chemical solution to the processing unit; a discharge unit including an ohmmeter and configured to discharge a solution from the processing unit; a first discharge solution line and a second discharge solution line each connected to a downstream side of the discharge unit; a converting unit disposed at a junction between the discharge unit and the two discharge solution lines, and a control unit that controls an overall operation of the substrate processing apparatus including the processing unit, the processing solution supply unit, the first chemical solution supply unit, the second chemical solution supply unit, the discharge unit, the first discharge solution line, and the converting unit, wherein the control unit is programmed to control the substrate processing apparatus such that the converting unit selectively flows only a portion of discharged solution to the first discharge solution line as a first recovered solution when it is detected by the ohmmeter that the discharged solution has a resistivity higher than approximately 13% of a maximum resistivity while the substrate is being rinsed in the processing unit after being processed with the first chemical solution, or flows only a portion of discharged solution to the second discharge solution line as a second recovered solution when it is detected by the ohmmeter that the discharged solution has a resistivity higher than approximately 13% of a maximum resistivity while the substrate is being rinsed in the processing unit after being processed with the second chemical solution, wherein the processing solution supply unit is equipped with a deionized water supply unit that supplies deionized water to the processing unit as a processing liquid, a first recovered solution supply unit that supplies the first recovered solution to the processing unit, and a second recovered solution supply unit that supplies the second recovered solution to the processing unit, and wherein the control unit is programmed to control the processing solution supply unit such that at least one of the deionized water and the first recovered solution is supplied to the processing unit when the substrate is either being processed in the processing unit with the first chemical solution or being rinsed in the processing unit after the processing with the first chemical solution, and at least one of the deionized water and the second recovered solution is supplied to the processing unit when the substrate is either being processed in the processing unit with the second chemical solution or being rinsed in the processing unit after the processing with the second chemical solution.