Substrate processing apparatus and substrate processing method

A substrate processing apparatus comprising:

• a substrate holder configured to hold a substrate;
• a treatment liquid supplier configured to supply treatment liquid onto a surface of the substrate to be cleaned;
• a cooler configured to that supplies a cooling medium for cooling the substrate;
• an impactor configured to apply an impact to a treatment liquid layer formed on the surface of the substrate to be cleaned;
• and
• a controller configured to control the treatment liquid supplier, the cooler, and the impactor, the controller being configured to
• control the cooler to cool the treatment liquid layer to a temperature lower than a freezing point to bring the treatment liquid layer to a supercooled state, and
• control the impactor to apply an impact to a starting point of forced freezing located away from a starting point of spontaneous freezing in the treatment liquid layer, when a temperature of the treatment liquid layer reaches a set temperature that is lower than the freezing point and higher than a temperature at which spontaneous freezing occurs.