Patent ID: 8848125

Claim:
An array substrate for a liquid crystal display device, comprising: a substrate; a thin film transistor having a signal line of a dual layered structure of a first copper compound layer and a first copper layer; and a pixel electrode connected to the thin film transistor, wherein the first copper compound layer includes nitrogen and is disposed between the substrate and the first copper layer, and wherein a top surface of the first copper layer directly contacts an insulating layer, wherein a capacitor including an island-shaped metal layer of a dual layered structure of only a second copper compound layer directly contacting the insulating layer and a second copper layer directly contacting the second copper compound layer is formed over the substrate, and the pixel electrode is in direct contact with the second copper layer of the island-shaped metal layer, wherein the island-shaped metal layer overlaps a gate line connected to the thin film transistor, and wherein the thin film transistor further comprises a gate electrode with a dual layered structure of the first copper compound layer and the first copper layer, and the first copper layer of the gate electrode is disposed between an active layer of the thin film transistor and the first copper compound layer of the gate electrode, wherein a top surface of the first and the second copper layers has a narrower width than a top surface of the first and the second copper compound layers, respectively.