Thin film transistor substrate and manufacturing method thereof

A thin film transistor (TFT) substrate, comprising:

• a gate interconnection line comprising a gate line and a gate electrode arranged on an insulating substrate;
• a gate insulating layer formed on the gate interconnection line;
• a semiconductor layer formed on the gate insulating layer;
• a data interconnection line comprising a data line, a source electrode, and a drain electrode formed on the semiconductor layer;
• a first passivation layer formed on the data interconnection line and exposing a portion of the drain electrode;
• a second passivation layer formed on the first passivation layer, wherein the outer sidewalls of the second passivation layer are positioned inside the outer sidewalls of the first passivation layer;
• and
• a pixel electrode connected to the drain electrode,
• wherein the first passivation layer is formed of a same material as the second passivation layer and the lattice structure of the first passivation layer is denser than the lattice structure of the second passivation layer.