Liquid supply unit, and apparatus and method for processing substrate

An apparatus for processing a substrate, the apparatus comprising:

• a housing having a processing space inside;
• a support unit configured to support the substrate in the housing;
• a nozzle configured to dispense a processing liquid onto the substrate supported on the support unit;
• and
• a liquid supply unit configured to supply the processing liquid to the nozzle,
• wherein the liquid supply unit includes:
• a container having a storage space in which the processing liquid is stored;
• a liquid supply tube through which the processing liquid flows from the container to the nozzle;
• and
• an ultrasonic-wave application member configured to apply ultrasonic waves to the processing liquid before the processing liquid is supplied to the nozzle,
• wherein the ultrasonic-wave application member includes:
• a liquid reservoir having an interior space in which a liquid is received;
• and
• an ultrasonic generator configured to apply ultrasonic waves to the liquid received in the liquid reservoir, and
• wherein part of the liquid supply tube is immersed in the liquid received in the liquid reservoir.