A conductive layer, including a lower layer made of refractory metal such as chromium, molybdenum, and molybdenum alloy and an upper layer made of aluminum or aluminum alloy, is deposited and patterned to form a gate wire including a gate line, a gate pad, and a gate electrode on a substrate. At this time, the upper layer of the gate pad is removed using a photoresist pattern having different thicknesses depending on position as etch mask. A gate insulating layer, a semiconductor layer, and an ohmic contact layer are sequentially formed. A conductive material is deposited and patterned to form a data wire including a data line, a source electrode, a drain electrode, and a data pad.