Substrate processing apparatus and substrate processing method

A substrate processing method performed by a substrate processing apparatus comprising:

• a processing vessel having an opening through which a substrate is carried into or out of the processing vessel;
• a cover body configured to be moved and configured to close the opening of the processing vessel;
• a substrate holder configured to hold the substrate horizontally with a front surface of the substrate facing upwards;
• a fluid supply device configured to supply a processing fluid in a supercritical state and a fluid in a gas state composed of a same material as the processing fluid in the supercritical state to the processing vessel, the fluid supply device comprising at least one supply line and at least one flow control device, wherein a first fluid supply configured to send the processing fluid in the supercritical state and a second fluid supply configured to send the processing fluid in the gas state which is the same material as the processing fluid sent from the first fluid supply are connected to the fluid supply device, the first fluid supply and the second fluid supply being connected to different fluid sources, the substrate processing method comprising:
• controlling the fluid supply device such that the processing fluid is supplied to the processing vessel from the first fluid supply in the first state, thereby flowing the processing fluid in the supercritical state in the processing vessel in a state that the substrate on the front surface of which a liquid is accumulated is carried in the processing vessel by the substrate holder, and replacing the liquid with the processing fluid in the supercritical state;
• and
• controlling the fluid supply device such that the processing fluid in the gas state is supplied to the processing vessel from the second fluid supply in the second state, thereby supplying, before the flowing of the processing fluid in the supercritical state and the replacing of the liquid with the processing fluid in the supercritical state, a purge gas into the processing vessel to turn an inside of the processing vessel into a purge gas atmosphere, when the cover body keeps the opening opened to carry the substrate into the processing vessel,
• wherein the purge gas and the processing fluid are composed of a same material and have different phases,
• wherein the processing vessel comprises a first discharge unit configured to discharge the processing fluid toward the opening from a position far from the opening,
• the first discharge unit is connected to the at least one supply line, and
• the substrate processing method further comprises:
• controlling the fluid supply device such that the processing fluid in the gas state is supplied to the processing vessel via the first discharge unit in the second state.