Substrate treating apparatus and liquid supplying method

The inventive concept provides a substrate treating apparatus. In an embodiment, the substrate treating apparatus includes a housing having a treatment space for treating a substrate in an interior thereof, a support unit that supports the substrate in the treatment space, a nozzle that supplies a liquid to the substrate positioned on the support unit, a liquid supply unit that supplies the liquid to the nozzle, and a controller that controls the liquid unit, the liquid supply unit includes a tank having an interior space for storing the liquid, and a first circulation line that circulates the liquid stored in the interior space and in which a first heater is installed, and the controller controls the first heater such that the first heater heats the liquid to a first temperature, at which particles in the interior of the liquid are not eluted.