Thin film transistor substrate of horizontal electric field type liquid crystal display device and fabricating method thereof

A method of fabricating a thin film transistor substrate of a horizontal electric field type liquid crystal display device, comprising:

• a first mask process of forming a gate line, a gate electrode connected to the gate line, a common line parallel to the gate line and a common electrode extended from the common line from a first conductive layer on a substrate;
• a second mask process of depositing a gate insulating film, forming semiconductor pattern and forming a data line crossing the gate line and the first common line, a source electrode and a lower data pad electrode connected to the data line, a drain electrode opposed to the source electrode, a dummy pattern connected to the drain electrode in parallel to the common electrode from the second layer on the semiconductor pattern;
• and
• a third mask process of coating a protective film, patterning the protective film and etching the dummy pattern to expose the side surface of the drain electrode to provide a pixel hole having an elongated shape in parallel with the common electrode, and forming a pixel electrode connected to a side surface of the drain electrode from a third conductive layer within the pixel hole.