TWI719448B

The present invention addresses the problem of reducing the amount of processing liquid used for concentration control in a substrate processing device. This substrate processing device performs predetermined processing on a substrate by discharging a processing liquid, containing a chemical and pure water, onto the substrate. This substrate processing device is provided with: a chemical supply unit that supplies a chemical containing a predetermined component; a pure water supply unit that supplies pure water; a storage tank for storing the processing liquid which contains the chemical supplied from the chemical supply unit and the pure water supplied from the pure water supply unit, and thus has a lower concentration of the predetermined component than the chemical; a substrate processing unit that performs the predetermined processing on the substrate by discharging the processing liquid onto the substrate; a supply pipe that serves as a flow passage of the processing liquid from the storage tank to the su