Abstract: A substrate processing apparatus includes a tower, a plurality of individual exhaust pipes, a collecting exhaust pipe, a switcher, an outside gas introducer, and a controller. The tower includes a plurality of processing parts aligned in a vertical direction. The switcher switches between connection and disconnection between each of the individual exhaust pipes and the collecting exhaust pipe. The outside gas introducer includes a flow passage introducing outside gas from outside to the collecting exhaust pipe. The controller controls the guide area of the outside gas introducer, based on individual guide areas corresponding to the plurality of processing parts and switching states of the switcher. The individual guide areas corresponding to the plurality of processing parts are set according to positions at which the plurality of processing parts are disposed.

Abstract: This invention relates to a substrate processing technique for performing a pressure increasing step, a pressure keeping step and a pressure reducing step in this order in a processing container. A flow rate of a processing fluid in a processing space is suppressed to a second flow rate lower than a first flow rate while maintaining the processing space at a first pressure between the pressure increasing step and the pressure keeping step or in an initial stage of the pressure keeping step. In this way, the mutual diffusion between the processing fluid and a liquid in the processing space is promoted. After this diffusion proceeds, the substrate is dried by the discharge of the processing fluid from the processing space.