Liquid supply unit, substrate treating apparatus, and method for removing bubbles

A substrate treating apparatus comprising:

• a substrate support unit configured to support a substrate;
• and
• a liquid supply unit configured to supply a treatment liquid in which a first liquid and a second liquid are mixed, onto the substrate supported by the substrate support unit,
• wherein the liquid supply unit includes:
• a nozzle configured to discharge the treatment liquid;
• a first liquid supply line configured to supply the first liquid to the nozzle;
• and
• a second liquid supply line configured to supply the second liquid to the nozzle, and
• wherein the nozzle includes:
• a body having a mixing space in which the first liquid and the second liquid are mixed and a buffer space extending from the mixing space, in the interior of the body;
• and
• a collision member located in the buffer space and configured to decrease a flow velocity of the treatment liquid supplied to the buffer space;
• and
• wherein the collision member includes:
• a collision body configured to divide the buffer space into an upper space and a lower space and having an open-topped vessel shape, wherein the upper space is between the mixing space and the lower space;
• and
• a ring plate surrounding the collision body and having an annular ring shape extending radially between a free edge of the collision body and the body, wherein a plurality of ring holes are formed in the ring plate and arranged along a circumferential direction of the ring plate.