THIN FILM TRANSISTOR SUBSTRATE AND METHOD FOR FABRICATING THE SAME TO PREVENT DRAIN ELECTRODE FROM BEING UNDERCUT

摘要

PURPOSE: A TFT(Thin Film Transistor) substrate and a method for fabricating the TFT substrate are provided to cover an upper layer of a drain electrode having a double-layer structure with a passivation layer to prevent one side of the upper layer of the drain electrode from being undercut when the passivation layer is etched to form a contact hole. CONSTITUTION: A TFT substrate includes an insulating substrate(110), a plurality of gate lines formed on the insulating substrate, a gate insulating layer(140) formed on the gate lines, and a semiconductor layer formed on the gate insulating layer. The TFT substrate further includes a plurality of data lines(171) each of which is composed of an upper layer(171q) and a lower layer(171p) and drain electrodes(175) each of which is composed of an upper layer(175q) and a lower layer(175p) formed on the semiconductor layer, a passivation layer(180) formed on the data lines, and a plurality of pixel electrodes(190) formed on the passivation layer and respectively connected to the drain electrodes. The upper layer of each drain electrode is covered by the passivation layer and a part of the lower layer is exposed and connected to the corresponding pixel electrode.