Slit coater having pre-applying unit and coating method using the same

1. A method for fabricating an LCD substrate using a slit coater, the method comprising:

providing a table on which an LCD substrate is mounted;

providing a slit nozzle configured to apply a coating solution onto a surface of the LCD substrate;

providing a pre-applying unit including a washing container filled with washing solution, a rotating roller disposed in the washing container and configured to receive pre-applied coating solution from the slit nozzle, first, second, and third washing solution spray nozzles installed at one side, the opposite side, and a lower portion of the washing container, respectively, pre-applying coating solution removing units installed under and above the second washing solution spray nozzle, respectively, a pre-applied coating solution drain (1 st drain) installed outside the washing container, a drain (2 nd drain) for discharging extra washing solution within the washing container and a coating solution separating unit, wherein one end portion of the coating solution separating unit is adjacent to a surface of the rotating roller;

pre-applying a coating solution onto the surface of the rotating roller before or after the coating solution is applied onto the surface of the LCD substrate;

1 st diluting the pre-applied coating solution by spraying washing solution from the first washing solution spray nozzle;

discharging at least some of the 1 st diluted pre-applied coating solution to the 1 st drain through the coating solution separating unit;

washing some remaining 1 st diluted pre-applied coating solution through the washing solution in the washing container;

2 nd diluting and removing some remaining washed 1 st diluted pre-applied coating solution by the second and third washing solution spray nozzles and the pre-applying coating solution removing units;

providing a first storage tank for storing new washing solution and a second storage tank for storing used washing solution;

supplying the new washing solution to the second washing solution spray nozzle;

discharging the extra washing solution within the washing container to the 2 nd drain and collecting the extra washing solution in the second storage tank through a drain pump;

supplying the collected extra washing solution to the first and third washing solution spray nozzles through a transfer pump;

providing a third valve and a second filter installed between the transfer pump and the third washing solution spray nozzle for filtering washing solution being supplied to the drain pump;

providing a fourth valve installed between the washing container and the drain pump and a fifth valve installed between the 2 nd drain and the drain pump;

providing a second valve and a sixth valve installed between the second filter and the first washing solution spray nozzle;

providing a washing solution drain (3 rd drain) configured to discharge the used washing solution through the sixth valve instead of being reused depending upon user's choice; and

applying the coating solution to the LCD substrate.

2. The method of claim 1 further comprising:

providing a supply pump configured to supply the new washing solution to the second washing solution spray nozzle.

3. The method of claim 2 further comprising:

providing a line coupling the supply pump to the second washing solution spray nozzle; and

providing a filter in the line and configured to substantially remove impurities of the washing solution.

4. The method of claim 1 , wherein the washing solution comprises a highly volatile organic solvent.

5. The method of claim 1 further comprising providing a driving unit and driving the slit nozzle in a predetermined direction over the LCD substrate.