Sacrificial-film removal method and substrate processing device

A substrate processing apparatus, including:

• a substrate holding unit holding a substrate provided with a plurality of struts and a sacrificial film embedded between the plurality of struts;
• an etchant supply unit for supplying an etchant to the substrate held by the substrate holding unit;
• an etching gas supply unit for supplying an etching gas to the substrate held by the substrate holding unit;
• a rinsing liquid supply unit for supplying a rinsing liquid to the substrate held by the substrate holding unit;
• a substrate rotating unit for rotating the substrate held by the substrate holding unit;
• and
• a control unit controlling the etchant supply unit, the etching gas supply unit, the rinsing liquid supply unit and the substrate rotating unit, wherein
• the control unit performs a wet etching step where the sacrificial film is removed to its halfway depth by supplying an etchant to the surface of the substrate, a rinse step where a residue adhering to the surface of the substrate is washed out by supplying a rinsing liquid to the surface of the substrate after the wet etching step, a drying step where a liquid component on the surface of the substrate is removed after the rinse step, and a dry etching step where the sacrificial film remaining on the surface of the substrate is removed by supplying an etching gas to the surface of the substrate after the drying step.