Substrate processing apparatus and substrate processing method

A substrate processing apparatus, comprising:

• a substrate holder which holds a substrate in a horizontal posture;
• a liquid film former which forms a liquid film by supplying a liquid on an upper surface of the substrate held by the substrate holder;
• a cooling gas discharge nozzle which discharges cooling gas of a temperature lower than a freezing point of the liquid forming the liquid film to the liquid film and thereby freezes the liquid film;
• a remover which removes a frozen film formed by freezing the liquid film from the substrate;
• a collector which includes a side wall for laterally surrounding the substrate held by the substrate holder and is configured such that the substrate is housed in an internal space enclosed by the side wall, an opening for exposing an upper part of the substrate is formed by an upper end part of the side wall and the liquid falling down from the substrate is collected;
• and
• a drainer which drains a fluid in the internal space of the collector to outside,
• wherein the drainer reduces a drain amount of the fluid from the internal space when the cooling gas is discharged to the liquid film from the cooling gas discharge nozzle than when the liquid is supplied to the substrate from the liquid film former.

A substrate processing method, comprising:

• a substrate holding step of holding a substrate in a horizontal posture;
• an air flow generating step of generating a down flow by gas flowing from top to bottom around the substrate;
• a liquid film forming step of forming a liquid film by supplying a liquid on an upper surface of the substrate;
• a freezing step of freezing the liquid film by supplying cooling gas of a temperature lower than a freezing point of the liquid forming the liquid film to the liquid film;
• and
• a removing step of removing a frozen film formed by freezing the liquid film from the substrate,
• wherein a flow velocity of the down flow in the freezing step is set lower than a flow velocity of the down flow in the liquid film forming step.