Method for fabricating liquid crystal display device

A method for fabricating a liquid crystal display device, comprising:

• forming a gate electrode, a storage electrode and a gate pad pattern on a substrate;
• forming a first insulating layer covering the gate electrode, the storage electrode and the gate pad pattern on the substrate;
• forming a semiconductor layer on the first insulating layer;
• forming a conductive layer on the semiconductor layer;
• forming an active region and a data pad pattern by patterning the conductive layer and the semiconductor layer;
• forming a second insulating layer covering the active region and the data pad pattern;
• forming a plurality of openings on the second insulating layer using a first photoresist pattern as a mask, wherein the openings include a first opening exposing the conductive layer on a channel region, a second opening exposing the conductive layer on a drain region, a third opening exposing the gate pad pattern region and a fourth opening exposing the conductive layer on the data pad pattern;
• forming a transparent electrode material on the second insulating layer having the plurality of openings;
• forming a pixel electrode, gate pad and data pad by patterning the transparent electrode materials using a second photoresist pattern as a mask;
• removing the second photoresist pattern on the second insulating layer;
• and
• removing the conductive layer and the second insulating layer at the channel region using the pixel electrode as a mask, thereby forming a source and drain electrodes.

A method for fabricating a thin film transistor for a liquid crystal display device, comprising:

• forming a gate electrode;
• forming a first insulating layer on the gate electrode;
• forming a semiconductor layer on the first insulating layer having a first etching rate;
• forming a conductive layer on the semiconductor layer, the conductive layer having a second etching rate;
• forming a second insulating layer having a third etching rate;
• forming plurality of openings on the second insulating layer using a first photoresist pattern;
• forming a pixel electrode on the second insulating layer using a second photoresist pattern;
• and
• forming a source electrode and a drain electrode by removing the conductive layer and the semiconductor layer on a channel region using the second photoresist pattern as a mask, wherein the removing includes using at least one etchant selected based on the first, second, and third etching rates, and wherein the first etching rate is higher than an etching rate of the first insulating layer, the second etching rate is lower than the etching rate of the first insulating layer, and the third etching rate is higher than the second etching rate.