Substrate drying apparatus and substrate drying method

An apparatus for drying a target substrate, comprising:

• a process bath having a first region for containing said substrate, and a second region for containing a volatile treatment liquid;
• heating means for evaporating said treatment liquid to form evaporated treatment liquid;
• cooling means arranged above said first region, for condensing evaporated treatment liquid to form condensed treatment liquid;
• a receiver arranged between said first and second regions, for receiving a mixture of water and condensed treatment liquid when said substrate is being dried in said first region, said water having been removed from said substrate by evaporated treatment liquid while said condensed treatment liquid having been generated by condensation of evaporated treatment liquid;
• an exhaust pipe connected to said receiver, for exhausting said mixture from said receiver to an outside of said process bath;
• a valve arranged on said exhaust pipe, for opening and closing said exhaust pipe;
• a branch pipe connected to said exhaust pipe at a location between said receiver and said valve, and having a discharge port located in said process bath and above said treatment liquid, for returning condensed treatment liquid from said receiver to said second region, in a state where said valve is closed when no target substrate is being dried in said first region.