Substrate drying method and substrate processing apparatus

A substrate drying method for drying a front surface of a substrate having a pattern, the substrate drying method comprising:

• a sublimation-agent-liquid-film placing step of placing a liquid film of a sublimation agent in a liquid state thereof on the front surface of the substrate, the sublimation agent contained in the liquid film of the sublimation agent having a temperature higher than a freezing point of the sublimation agent;
• a high vapor-pressure liquid placing step of placing a liquid film of a high vapor-pressure liquid that has vapor pressure higher than that of the sublimation agent in the liquid state and that does not include water on the liquid film of the sublimation agent placed on the front surface of the substrate, the high vapor-pressure liquid contained in the liquid film of the high vapor-pressure liquid having a temperature higher than the freezing point of the sublimation agent;
• a vaporizing/cooling step of losing vaporization heat in response to vaporization of the high vapor-pressure liquid, and, cooling the sublimation agent in the liquid state thereof from the temperature higher than the freezing point thereof to the freezing point or a temperature lower than the freezing point so as to change the sublimation agent in the liquid state to the sublimation agent in a solid state thereof, thereby solidifying the liquid film of the sublimation agent, and, forming a sublimation-agent film of the sublimation agent in the solid state on the front surface of the substrate;
• and
• a sublimating step of sublimating the sublimation-agent film.