Patent ID: 7907226

Claim:
A method of fabricating an array substrate for a liquid crystal display device, comprising: providing a substrate having a pixel portion and a driving portion; forming a first gate electrode on the substrate in the pixel portion, and a second gate electrode and a third gate electrode on the substrate in the driving portion; forming a gate insulating layer on the first, second and third gate electrodes; forming a polycrystalline silicon layer on the gate insulating layer; doping a first portion of the polycrystalline silicon layer in the driving portion with p-type impurities; doping a second portion of the polycrystalline silicon layer in the driving portion and a third portion of the polycrystalline silicon layer in the pixel portion with n-type impurities; forming an interlayer insulating layer having contact holes exposing the first, second and third portions of the polycrystalline silicon layer; forming a metal layer on the interlayer insulating layer, the metal layer contacting the first, second and third portions of the polycrystalline silicon layer through the semiconductor contact holes; forming a first photoresist pattern having a first thickness and second photoresist pattern having a second thickness on the metal layer, the first thickness being greater than the second thickness; sequentially etching the metal layer and the polycrystalline silicon layer using the first and second photoresist patterns as an etch mask to form a first semiconductor layer in the pixel portion, and second and third semiconductor layers in the driving portion; partially removing the first and second photoresist patterns such that the first photoresist pattern has a third thickness smaller than the first thickness; etching the metal layer using the first photoresist pattern having the third thickness to form first source and drain electrodes in the pixel portion, and second and third source and drain electrodes in the driving portion; and forming a pixel electrode contacting the first drain electrode.