US Patent 9607844 Substrate processing method and substrate processing apparatus

The method includes holding a substrate horizontally with a holding and rotating mechanism; introducing processing liquid from a fluid introduction portion of, in a processing liquid pipe in which a processing liquid nozzle having a discharge port at a tip end is provided at one end, the other end of the processing liquid pipe into the processing liquid pipe so as to discharge the processing liquid from the discharge port toward the substrate; introducing, after stopping the processing liquid discharge step, a gas from the fluid introduction portion into the processing liquid pipe so as to extrude the processing liquid within the processing liquid pipe and within the processing liquid nozzle outwardly; and stopping, after starting the introduction of the gas, the introduction of the gas into the processing liquid pipe with the processing liquid being left within the processing liquid pipe and/or the processing liquid nozzle.