Substrate processing apparatus and method for determining deterioration degree of conductive pipe

A substrate processing apparatus comprising:

• a substrate holder configured to hold and process a substrate;
• a nozzle configured to eject a processing liquid to the substrate held by the substrate holder;
• a conductive pipe connected to the nozzle and configured to supply the processing liquid to the nozzle;
• a ground line that connects the conductive pipe and a reference potential;
• a liquid receiver provided around the substrate holder and configured to receive the processing liquid ejected from the nozzle;
• and
• a deterioration degree measuring unit configured to measure a deterioration degree of conductivity of the conductive pipe,
• wherein the deterioration degree measuring unit includes:
• a measurement liquid supply configured to supply a measurement liquid to the conductive pipe and eject the measurement liquid from the nozzle;
• a potential difference generator configured to impart a potential difference between a liquid contact surface of the liquid receiver and the reference potential;
• and
• an ammeter configured to, when the measurement liquid is ejected from the nozzle to the liquid receiver, measure a current value of a current flowing through a charge moving path established via the measurement liquid between the liquid contact surface of the liquid receiver and the ground line.