Array substrate for liquid crystal display device and the fabrication method of the same

Abstract

The present invention discloses a four-mask method of manufacturing an array substrate of a liquid crystal display device and the liquid crystal display device having the same array substrate. The method includes forming a plurality of gate lines, gate electrodes and gate extension lines by depositing a first metallic material on a substrate and patterning the first metallic material with a first mask, the gate extension lines extending toward the opposite direction of the gate electrodes; forming a first insulating layer on the whole surface having gate lines, gate electrodes, and gate extension lines; forming a plurality of data lines, source electrodes, drain electrodes, and capacitor electrodes over the gate lines by depositing a semiconductor layer, an ohmic contact layer and a second metallic material sequentially on the first insulating layer, and patterning the second metallic material and the ohmic contact layer with a second mask; forming a passivation layer and a plurality of first and second contact holes by depositing a second insulating layer on the data lines, the source electrodes, the drain electrodes and the capacitor electrodes, and patterning the second insulating layer with a third mask, the first contact holes exposing a portion of the drain electrode, the second contact holes exposing a portion of the capacitor electrodes; and forming a plurality of pixel electrodes by depositing a transparent conductive layer on the passivation layer, and patterning the transparent conductive layer by a fourth mask, the pixel electrodes contacting the drain electrodes through the first contact holes and contacting the capacitor electrodes through the second contact holes.